2006 PROGRESS REPORT - ENEA - Fusione · European Lead-Cooled Fast System 104 Very high temperature reactor 106 B1.3 Nuclear Safety 107 Code validation and accident analysis 107 Severe

2006

2006

PROGRESS REPORT Nuclear Fusion and Fission, and Related Technologies Department

ITALIAN NATIONAL AGENCY FOR NEW TECHNOLOGIES ENERGY AND THE ENVIRONMENT

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Cover picture: The six BNC cables andPiccolo–Micromegas assemby inside the TRIGAreactor

See http://www.fusione.enea.it for copy of this report

This report was prepared by the Scientific Publications Office from contributions provided by the scientific andtechnical staff of ENEA’s Nuclear Fusion and Fission, and Related Technologies Department.

Scientific editors: Paola Batistoni, Adriana Romagnoli, Gregorio VladDesign and composition: Marisa Cecchini, Lucilla Crescentini, Lucilla GhezziArtwork: Flavio MigliettaEnglish revision: Carolyn Kent

Tel: +39(06)9400 5016 Fax: +39(06)9400 5015e-mail: [email protected]

Published by:

ENEA - Nucleo di AgenziaEdizioni Scientifiche,Centro Ricerche Frascati,C.P. 6500044 Frascati, Rome (Italy)

Contents

A FUSION PROGRAMME 6

A1 MAGNETIC CONFINEMENT 6

Introduction 6A1.2 FTU Facility 7A1.3 Experimental Results 8

Lower hybrid current drive studies in ITER-density-relevant plasmas 8Liquid lithium limiter experiment 10MHD real-time control experiment 12Electron cyclotron current drive experiment 12Disruption studies 13Dusty plasmas 14

A1.4 Plasma Theory 16Theory of beta-induced Alfvén-eigenmodes 17Electron fishbones: theory and experimental evidence 17Analysis and modelling of LHW propagation in toroidal plasmasby asymptotic methods 18Modelling of the ICRH experiment on JET 19Simulation of burning plasma dynamics by ICRH accelerated minority ions 20Particle simulation of bursting Alfvén modes in JT–60U 21Theory of Alfvén waves and energetic particle physics in burning plasmas 23Nonlinear equilibria, stability and generation of zonal structures in toroidal plasmas 23

A1.5 JET Collaboration 24Participation in the JET EP/EP2 24Participation in experimental campaigns C15-C17 26

A1.6 Proto–Sphera 29

A2 PRELIMINARY DESIGN OF FT3 32

Introduction 32A2.2 Scientific Motivation of the Proposal 33

A2.3 Preliminary Design Description 36

A3 TECHNOLOGY PROGRAMME 40

Introduction 40

A3.2 Divertor, First Wall, Vacuum Vessel and Shield 40Manufacturing of small-scale W monoblock mockups 40Engineering Design Activities: V and VI test campaigns 42Hydraulic characterisation of full-scale divertor components 42H permeation through EUROFER and heat exchanger material (Incoloy, Inconel) 43Formal trials for the new ITER divertor cassette refurbishment 43

A3.3 Breeder Blanket and Fuel Cycle 44DEMO breeding blanket 44European Breeding Blanket Test Facility 44Thermo-mechanical characterisation of HCPB mockup 44TRIEX loop for studying technologies for extracting tritium from Pb-17Li 46Conceptual design of auxiliary systems for HCPB-TBM 46Structural analyses during em loading 46VDS catalyst tests 47Permeator tubes 48

A3.4 Magnet and Power Supply 48ITER magnet casing welds 48ITER pre-compression ring fibreglass composite material 48High-frequency/high-voltage solid-state modulator for ITER gyrotrons 48

A3.5 Remote Handling and Metrology 48

A3.6 Neutronics 50Quality assurance for neutronics analysis for ITER 50ITER systems: nuclear design 51TBM HCPB and HCLL neutronics experiments 51Experimental validation of neutron cross sections for fusion-relevant materials 52

A3.7 Materials 53Flat-top indenter for mechanical characterisation 53

A3.8 IFMIF 54Remote handling of the back-plate bayonet concept – bolted solution 54Lithium corrosion and chemistry: LIFUS III facility 54Preliminary remote handling handbook for IFMIF facilities 55Inventories and dose rates induced by deuterons and neutrons inthe accelerator system 56Inventories and dose rates induced by deuterons and neutrons inthe cooling system 56

A3.9 Safety and Environment, Power Plant Studies and Socioeconomics 56Failure mode and effect analysis for the European test blanket modules 56Failure mode and effect analysis for remote handling transfer systems of ITER 57Validation of computer codes and models 57Dust removal experiments in STARDUST 58Feasibility study of a torus-shaped facility for dust mobilisation studies 58Post-accident occupational exposure and radioprotection 58Integration of design modifications (in Rapport Préliminaire de Sûreté)to tritium building and detritiation system 59Collection and assessment of data related to JET occupationalradiation exposure 60JET data collection on malfunctions and failures of ICRH system components 60JET dust in-vitro experiment: result assessment and in-vivo experimentliterature review 60Study on recycling of fusion activated material 61

A4 SUPERCONDUCTIVITY 62

Introduction 62

A4.2 ITER and ITER-Related Activities 62ITER toroidal field cable conductor 62Current redistribution study on ITER conductors 64EFDA dipole 64Barrel bending experiments 65Optimisation of NbTi strand for PF1/PF6 performance 65

A4.3 JT-60SA 66

A4.4 High–Temperature Superconducting Materials 66Evolution and control of cube texture in Ni-W substrates for YBCO-coatedconductors 66Nickel-copper alloys as textured substrates for YBCO–coated conductors 68MOD-TFA YBCO films 69

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Introduction of artificial pinning sites in YBCO films 70Magnetic characterisation of superconducting wires for fast rampedsuperconducting dipoles 71MARIMBO experiment: application of MgB2 72Transport and thermal stability characterisation of HTS wires and tapes:analysis of quench propagation on YBCO-coated conductors 73

A5 INERTIAL FUSION 74

A6 PUBLICATIONS, PATENTS AND EVENTS 78

A6.1 Publications 78Articles 78Articles in course of publication 81Contributions to conferences 82Reports 86

A6.2 Patents 86

A6.3 Conferences and Events 87

A6.4 Seminars 87

B FISSION TECHNOLOGY 88

B1 R&D ON NUCLEAR FISSION 88

B1.1 Innovative Fuel Cycles Including Partitioning andTransmutation 88Partitioning technology 88Transmutation systems and related technology 90VELLA - Virtual European Lead Laboratory 102

B1.2 Evolutionary and Innovative Reactors 102International Reactor Innovative and Secure 103European Lead-Cooled Fast System 104Very high temperature reactor 106

B1.3 Nuclear Safety 107Code validation and accident analysis 107Severe accident analysis 109Reliability and risk analysis 111

B1.4 Nuclear Data 112General quantum mechanics 112Nuclear reaction theory and experiments 113Nuclear data processing and validation 113Computer code development 115Radioactive ion-beam production for nuclear-structure studies 116

B1.5 TRIGA RC-1 and RSV TAPIRO Plant-Operation for ApplicationDevelopment 117

B2 MEDICAL, ENERGETIC AND ENVIRONMENTAL APPLICATIONS 118

B2.1 Boron Neutron Capture Therapy 118The epithermal column EPIMED at TAPIRO 118Employment of the thermal column HYTHOR at TAPIRO 121

Study of BNCT applied to lung tumours 121Design of a facility at TRIGA to treat explanted livers 122

B2.2 Solar Thermal Energy 123

B2.3 Development Activities for Antarctic Drilling 124

B3 PARTICIPATION IN INTERNATIONAL WORKING GROUPSAND ASSOCIATIONS 128

B4 PUBLICATIONS 130

B4.1 Publications 130Articles 130Reports 133Contributions to conferences 134

C NUCLEAR PROTECTION 140

C1 RADIOACTIVE WASTE MANAGEMENT AND ADVANCEDNUCLEAR FUEL CYCLE TECHNOLOGIES 140

Introduction 140C1.2 Entrustment of ENEA’s Fuel Cycle Facilities and

Personnel to Sogin 140

C1.3 Characterisation, Treatment and Conditioning of NuclearMaterials and Radioactive Waste 140

C1.4 Radioprotection and Human Health 142Methodological proposal for the evaluation of a physiological comfortindex in indoor environments 142LCA of strippable coating and the principal competing technologyused for nuclear decontamination 143

C1.5 Integrated Service for Non-Energy Radwaste 143

C1.6 Transport of Nuclear Material 144Packaging for transport of radioactive material 144

C1.7 Disposal of Radioactive Waste 145Artificial barriers for disposal units 145

D MISCELLANEOUS 146

D1 Advances in the IGNITOR Programme 146

D2 Ultra-Pure Hydrogen Production 147

D3 Non-ITER Activities 148

D4 Condensed Matter Nuclear Science 149

ORGANISATION CHART 152

ABBREVIATIONS AND ACRONYMS 154

Preface This report describes the research activity carried out

during 2006 by the laboratories belonging to the ENEANuclear Fusion and Fission, and Related TechnologiesDepartment (Dipartimento Fusione, Teconologie ePresidio Nucleari (FPN)).

An important point to note is that during 2006 ENEAimplemented a new organisation that combines fusionand fission activities in the same department FPN. Thischoice is clearly advantageous for both fields.

In the fusion field, a historical event took place in 2006 -the signature of the agreement for the construction ofITER in Europe (Cadarache). ITER concentrates the efforts

of the most advanced countries in the world in utilizing fusion as a safe, environmentally sustainableand inexhaustible energy source. The participants in this challenging enterprise are Europe, China,Korea, India, Japan, the Russian Federation and the United States.

ENEA, in the framework of the Euratom-ENEA Association for fusion, continues to contribute tobroadening plasma physics knowledge as well as to developing the relevant technologies. Thisreport describes the 2006 research activities carried out by the ENEA Fusion Research Group of theFPN with the contributions of other ENEA research groups. The following fields were addressed:magnetically confined nuclear fusion (physics and technology), superconductivity and inertialfusion.

During 2006 the scientific activity at the Frascati Tokamak Upgrade (FTU) was focussed on ITER-relevant aspects of plasma scenarios. In the meantime the conceptual design activity and a reportdiscussing the scientific motivation of the FT3 device in the context of the European AccompanyingProgramme were completed. This new proposal also involves the other participants in the ENEA-Euratom Association, namely, the Reversed Field Pinch Experiment (RFX) Consortium and theNational Research Council (CNR) Milan. The technological R&D programme was performed in theITER framework and under the Broader Approach Agreement with Japan. Collaboration withindustry in view of the participation in construction of ITER was further strengthened.

In the fission field one of the most important events at international level was the Global NuclearEnergy Partnership (GNEP), launched by the USA Government. The GNEP is a comprehensivestrategy aimed at making it possible to use economical, environmentally responsible nuclear energyto meet growing electricity demand worldwide, while virtually eliminating the risk of nuclear materialmisuse. This initiative, together with the Generation-IV projects and the 6th European UnionFramework Plan, is the reference frame in which the ENEA FPN Department operated during 2006in the nuclear fission field.

ENEA benefits from a wide range of collaborations with other international research centres andwith industry. Several patents were granted in 2006 and spin-off activities are in progress. High-techservices are supplied to Italian industry.

The work summarised in this report is amply documented in published articles and conferencecommunications (most of which invited).

Frascati, December 2006 Alberto Renieri

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A1 Magnetic Confinement

Progress Report 2006 6

Scientific activity at the Frascati Tokamak Upgrade (FTU) continued to be focussed on ITER-relevant

aspects of plasma scenarios. Reliable plasma operations with lithizated walls were achieved thanks to the

newly installed liquid lithium limiter (LLL). A new experimental activity on dust creation/mobilisation was also

started. Good results have been obtained although the 2006 experimental activity was somewhat limited.

The spring campaign was first delayed by lightening hitting the electrical substation and then shortened

because of an optical window cracking due to focus deterioration of the laser beam of the Thomson

scattering diagnostic. Including a short autumn campaign, the whole 2006 experimental activity fully

dedicated only 27 days to scientific programmes, out of a total of 50 operational days.

The objective to push the performance of the wide (r/a ≥ 0.6, with r the radial coordinate and a the minor

radius of the torus) internal transport barriers (ITBs) obtained in 2005 was not pursued in 2006 because of

limited availability of lower hybrid (LH) power, necessary for controlling the current profile at higher plasma

current and density. Experiments and studies were concentrated on ion transport in the presence of electron

ITBs with ion heating determined by electron-ion collisional energy transfer.

The LLL installed in 2005 allowed operations with extremely clean plasmas where the content of heavy Z

impurities, typical of FTU metallic operations, was close to zero. In these conditions, discharges exhibit

better confinement (~20% above ITER-97L), comparable with results obtained with freshly boronized walls.

With the LLL acting as the main limiter new regimes exhibiting peaked density profile, up to density limit

values, were found.

Experiments dedicated to magnetohydrodynamic (MHD) control were aimed at improving m=2 mode

stabilisation by modulating the electron cyclotron (EC) power in phase with the island rotation and at

enhancing the signal-to-noise ratio to better identify the electron cyclotron heating (ECH) absorption

position. Disruptions (induced by impurity injection and the density limit) were mitigated by electron

cyclotron resonance heating (ECRH) power and were completely avoided when the power deposition

coincided with the location of the modes responsible for the disruptions.

Theoretical and experimental activities concerning dust in the plasma scrape-off layer (SOL) were

successfully started in collaboration with the universities of Naples and Molise and with the Max Planck

Institute for Extraterrestrial Physics. In the experimental work, in particular, evidence of dust particles

collected in the SOL of FTU discharges was found on Langmuir probes.

Mutual and positive feedbacks between theory and experiments led to i) clear identification of high-

frequency MHD activity in FTU; ii) modelling of ion cyclotron resonance heating (ICRH) experiments on the

Joint European Torus (JET); iii) numerical simulation of energetic ion transport and nonlinear Alfvénic

fluctuations in situations of experimental relevance in present-day experiments, in the framework of a

collaboration with the Japan Atomic Energy Research Institute (JAERI) JT-60U team.

More basic activities were focused on electron-fishbone mode excitations by LH additional power, the

propagation and absorption of radiofrequency (rf) waves in toroidal plasmas, the investigation of energetic

ion dynamics in burning plasmas, and activities on plasma turbulence and turbulent transport.

In 2006 the JET experimental campaigns were put off to July, and the participation of Frascati scientists was

then limited to restart and high-level commissioning of the JET Enhancement Programme (EP) and the

organisation of new enhancements for JET-EP2. The main experimental activity was resumed in autumn

Progress Report 2006

A1.2 FTU Facility

During 2006 the FTU machine achieved 91% of successful pulses, continuing the high level of reliability ofthe previous years.

Experimental work started at the end of March and continued up to the first week of July withoutsuspensions. The second experimental session ran from mid-September to mid-October. In 2006, 1144shots were successfully completed out of a total of 1257 performed over 50 experimental days. Theaverage number of successful daily pulses was 23.11. Table A1.I reports the main parameters forevaluating the efficiency of the experimental sessions. Figure A1.1 reporting the indicator trend from 1999up to 2006 shows that experimental time and successful pulses are stable, while experimental days arelower due to power supply problems and to a vacuum loss caused by a hole in the scattering window.

For the control and data acquisition system:

a) Work was started on developing a software framework to obtain a user-friendly environment for carryingout all the phases (i.e., control law design, simulation, automatic source code generation, debug andsoftware release) related to the FTU real-time control system. A software simulation tool was alsoimplemented and released. The whole work should be finished by 2007. A 10 PC Cluster has beeninstalled to allow FTU data analysis in a Linux environment. In the initial phase the cluster is employedas a test-bed to characterise real-time network protocols suitable for ITER.

b) A set of computing resources was released on the EGEE-GRID (i.e., Enabling Grids for E-sciencE) siteof ENEA for the FUSION Virtual Organisation: in particular a 1-TB storage area is available for use by theIntegrated Tokamak Modelling Task Force.

c) A web tool was developed to handle the configuration of a data acquisition system (DAS) similar to theFTU control and data acquisition system (CODAS) and with the same data and parameter configuration.

d) Work was started for a European Fusion Development Agreement (EFDA) task aimed at achieving afully revised version of the ITER control data access and communication (CODAC) specifications readyfor fusion internal review. In particular, ENEA has to revise the CODAC documentation, bringing it up todate for April 2007; prepare and organise internal and external reviews (including experts outside fusion)and a peer review of the CODAC design in agreement with the ITER International Team and ITERParticipant Teams; incorporate into the CODAC design common proposals that will have to bediscussed in the review process.

To model the CODAC structure, the capabilities of UML language were studied. Preliminary resultsindicated that Matlab/Simulink could be suitable for the final design work, but a hybrid solution (UML codeinto Matlab/Simulink diagram) is being investigated.

7

2006, with ENEA having direct responsibility for experiments both in Task Force S1, regarding hybrid scenarios with

dominant electron heating, and in Task Force S2, on high-performance ITBs.

The FT3 conceptual design activity and a report discussing the scientific motivation of the device in the context of

the European programme were completed. Various plasma scenarios can be investigated and it is shown that the

various heating systems are capable of producing the plasma conditions needed for the ITER physics investigation.

The report includes a preliminary design of the machine, auxiliary heating systems and diagnostics, and a

preliminary assessment of different sites and construction and operation costs.

Finally, the construction of the poloidal field shaping coils of MULTI-PINCH (initial set-up of PROTO-SPHERA)

continued during 2006 and will be completed by the beginning of 2007. The collaboration with the United Kingdom

Atomic Energy Authority (UKAEA) continued, mainly on modelling and on experiments aimed at plasma start-up and

plasma current ramp-up in the absence of the central solenoid in MAST.

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A1.3 Experimental Results

Lower hybrid current drive studies in ITER-density-relevant plasmas

The LH radiofrequency (fLH=8 GHz) heating system in FTU is used mainly to create and maintainradial profiles of the toroidal current j(r) that are suitable for sustaining plasma regimes with an ITBthat improves core plasma confinement. The ECH radiofrequency system (fEC=140 GHz) facilitatesthis task, and the rf waves of both interact only with electrons. Ions are, instead, heated only viacollisional damping of the hotter electrons. These regimes are currently the most valuable option forsteady-state operation in ITER and future tokamak reactors. Indeed, the better confinement



Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. Total

Total pulses 0 0 103 130 268 385 0 0 120 251 0 0 1257

Successful pulses (sp) 0 0 97 117 251 343 0 0 113 223 0 0 1144

I(sp) 0.94 0.90 0.94 0.89 0.94 0.89 0.91

Potential experimental days 0.0 0.0 8.0 11.0 10.5 17.0 4.0 0.0 12.0 8.5 0.0 0.0 71.0

Real experimental days 0.0 0.0 4.0 6.5 10.5 15.5 0.0 0.0 4.5 8.5 0.0 0.0 49.5

I(ed) 0.50 0.59 1.00 0.91 0.00 0.38 1.00 0.70

Experimental minutes 0 0 1680 2136 4555 6294 0 0 2137 3913 0 0 20715

Delay minutes 0 0 743 1888 1943 3098 0 0 815 1388 0 0 9875

I(et) 0.69 0.53 0.70 0.67 0.72 0.74 0.68

A(sp/d) 24.25 18.00 23.90 22.13 25.11 26.24 23.11

A(p/d) 25.75 20.00 25.52 24.84 26.67 29.53 25.39

Delay per system (minutes)

Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. Total %

Machine 0 0 24 89 104 266 0 0 98 148 0 0 729 7.4

Power supplies 0 0 366 471 669 867 0 0 322 282 0 0 2977 30.1

Radiofrequency 0 0 0 20 87 286 0 0 0 100 0 0 493 5.0

Control system 0 0 16 17 158 352 0 0 89 120 0 0 752 7.6

DAS 0 0 77 30 156 116 0 0 6 42 0 0 427 4.3

Feedback 0 0 0 8 52 46 0 0 0 81 0 0 187 1.9

Network 0 0 0 0 0 0 0 0 0 0 0 0 0 0.0

Diagnostic systems 0 0 27 174 121 200 0 0 15 104 0 0 641 6.5

Analysis 0 0 149 179 173 492 0 0 108 393 0 0 1494 15.1

Others 0 0 84 900 423 473 0 0 177 118 0 0 2175 22.0

TOTAL 0 0 743 1888 1943 3098 0 0 815 1388 0 0 9875 100

Table A1.I – Summary of FTU operations in 2006

I(sp)

I(et)

I(ed)

0.5

0.7

0.9

1999 2001 2003 2005Years

Fig. A1.1 – Indicator trend from 1999 up to

2006. I(sp): successful/total pulses. I(et):

real/total experimental time. I(ed): real/total

experimental days

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obtained in ITB regimes would allow operation at a lowerplasma current Ip in order to obtain the same τE with respectto the standard scenario. In addition, demands on theexternal current drive (CD) sources would be greatly reduced because the self-generated bootstrap currentIbs would increase due both to the lower Ip, and to the steeper pressure radial gradients arising in reducedtransport conditions, Ibs/Ip∝Ip

2·∇p.

The peculiarity of FTU is that ITBs can be formed by using electron heating and current drive with no direction heating or external momentum injection, which is a similar condition to that foreseen for ITER. Theadditional capability to establish an ITB starting from a fully relaxed current profile at high density makesFTU unique. Unfortunately, in 2006 the LH and ECH performances were not at the level required forsignificant experimental progress, so activity in the ITB field was focussed mainly on exploiting at best thedata previously obtained and on preparing the 2007 experiments.

Crucial questions to be answered for ITER concern the effect collisional energy transfer between electronand ions has on ITBs and how electron ITBs, with little or no induced rotation, affect ion transport. Herethe FTU contribution may be important and indeed the 2005 report illustrates the encouraging results onthe first point, while ion transport has been treated recently in an overview of FTU results [A1.1] and in amore dedicated paper [A1.2]. Figures A1.2a) and A1.2b) plot the ion thermal conductivity χi during an ITBas a function of radius for the two most representative steady discharges, one obtained at the highestdensity (fig. A1.2a)), and the other at the widest radius (fig. A1.2b)). The vertical bars limit the variabilityrange of χi during the ITB evolution phase. Irrespective of the ITB radius (rITB) χi appears to drop belowneoclassical at r≤rITB. Although the magnitude of χi,neo might be overestimated due to the uncertainty onthe safety factor q(r), χi,neo∝q2, for two very different ITB discharges χi drops just at the barrier footprintand falls even below the value it has in the Ohmic phase. This is of particular relevance since energytransport is usually faster if the temperature increases, while Ohmic temperatures are lower. Therefore aq(r) profile with low shear (which is typical of ITB regimes) appears suitable for reducing not only theelectron but also the ion transport, without the support of induced plasma rotation. Although limited so farto low ion central temperature values Ti0 this result is promising for ITER. Consistently, the drop in theturbulence level close to the barrier foot derives from decorrelation of the modes that could affect bothelectron and ion transport [A1.3, A1.4].

The possible application of lower hybrid current drive (LHCD) to ITER, however, still has to satisfy therequirement of high efficiency ηCD. Previous FTU results [A1.5] show that ηCD does not degrade up to and

[A1.1] V. Pericoli–Ridolfini et al., Proc. 21st IAEA Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/OV_3-4.pdf, and submitted to Nuclear Fusion

[A1.2] V. Pericoli–Ridolfini et al., Proc. 21st IAEA Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/EX_P1-15.pdf

[A1.3] V. Pericoli–Ridolfini et al., Plasma Phys. Control. Fusion 47, B285–B301 (2005)

[A1.4] M. De Benedetti et al., Proc. 32th EPS Conference on Plasma Physics (Tarragona 2005), on line at:http://epsppd.epfl.ch/Tarragona/pdf/P4_035.pdf

[A1.5] V. Pericoli–Ridolfini et al., Nucl. Fusion 45, 1386-1395 (2005)

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# 26671 highest ne

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χi,neo

χi,exp

χi,exp

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Fig. A1.2 – Ion thermal conductivity vs normalised minor radius, for the

highest density a) and the widest b) steady ITB discharges. Experimental

(χi,exp) and neoclassical (χi,neo) ion thermal conductivities are shown in

full lines, while dotted segments limit the variability range during the

whole ITB phase. Also shown are the ITB radial location and the ion

thermal conductivity range during the Ohmic phase

a)

b)

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beyond the ITER density (line averagen_

e=1×1020 m-3), while the favourable scaling ofηCD with electron temperature Te leaves hope forthe desired value >0.35×1020Am-2/W. However,the lower ITER LH frequency (fLH,ITER=5 GHz)may induce some concern on the basis of thepast results on ASDEX [A1.6] and JET [A1.7].The ratio of plasma to wave frequency (fpe/fLH),which could be an important parameter, had tobe fpe/fLH≤15, while in ITER it will be ~18.Although fpe/fLH≤15 in FTU, some precursors ofefficiency loss started to appear: the frequencyspectral broadening of the LH pump was nolonger negligible, the main cause being theinteraction of the LH waves with the edgeplasma. Here, the low temperatures, even morethan 100 times below the core, and the relativelyhigh densities, larger than 0.1 times the core,can either exalt the linear scattering on densityfluctuations or trigger nonlinear phenomena,such as parametric decay instability (PDI). Botheffects, which however may also coexist, cancause noticeable degradation of the N||spectrum and of the trajectories of the launchedLH waves (N|| is the parallel index of refractionand governs the LHCD efficiency).

In this context both effects were modelled by considering the available data. For turbulent scatteringin the SOL, the model follows the one proposed in [A1.8]. More details can be found in [A1.9]. Forthe scattering case, figure A1.3 reports a comparison of the LH power radial deposition derived fromthe fast electron bremsstrahlung (FEB) camera and the deposition according to the newlydeveloped fast ray tracing code (FRTC) and to the conventional calculation [A1.10]: only whenscattering is taken into account is there good agreement with the experiment. The case consideredis the ITB discharge in figure A1.2b). For the PDI case figure A1.4 shows the fairly good agreementfor JET between the q(r) profiles derived from the motional Stark effect (MSE) diagnostic and thosecalculated with the newly developed code LHstar [A1.11], which takes into account the nonlinearinteraction LH waves-edge plasma. Conversely the agreement is a good deal poorer for the profilecalculated conventionally.

Liquid lithium limiter experiment

During 2006, experiments to test a liquid lithium limiter with a capillary porous system (CPS)configuration on FTU [A1.12, A1.13] were continued and a full analysis of the first results obtainedat the end of 2005 was performed. The programme in collaboration with TRINITI & Red Star(Russian Federation) was also begun: the aim is to investigate the behaviour of liquid lithium in viewof its possible application as plasma-facing material and in the framework of a more general studyon liquid metals. Lithium was chosen because of its low atomic number, good thermal properties



J LH

(r)

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r(m)0 0.05 0.15 0.250.1 0.2 0.3

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#27928, t=0.7s

FRTC - NOscattering

Hard-X ray(FEB)

FR

TC

+ s

catte

ring

q(r)

r/a0 0.2 0.4 0.6 0.8 1

10

8

6

4

2

0

LHstar

MSE

Conventional

Fig. A1.4 – Safety factor profile q(r) vs normalised

minor radius for a current-hole discharge of JET:

comparison between LHCD radial profiles from

experiment (MSE diagnostic, dashed line), from the

recently developed LHstar code (full line) and from

conventional calculation (dotted-dashed line)

Fig. A1.3 – Comparison between LHCD radial profiles in

FTU computed by FRTC: LH wave edge scattering by

density fluctuations (full line, FRTC+scattering), no

scattering (dash-dotted line, FRTC-NO scattering), and the

experiment (dashed line, same discharge as in fig. A1.2,

hard x ray [FEB])

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and strong capability to pump deuterium and impurityparticles. The LLL, composed of three similar units withdimensions respectively of 100 mm and 34 mm in poloidal andtoroidal directions has been inserted 1.0-2.0 cm within theSOL, from the bottom vertical port 1. It has been used fordepositing a thin Li film on the FTU metallic walls duringplasma discharge (lithization) and as a liquid material facing theplasma.

Infrared and visible detectors viewing the LLL surface, plus Langmuir probes placed 5 mm from the LLLleading edge, have been used to determine surface temperature [A1.14], Li release, electron density andtemperature in the SOL plasma at the LLL position. In 2006, experiments in Ohmic conditions confirmedthe previous results [A1.15, A1.16]. Plasma discharges with heating power up to 0.85 MW arecharacterised by the lowest Zeff, Prad and Dα signals (as monitor of particle recycling) ever observed onFTU, and whether the LLL is inserted or not inside the vacuum chamber makes no substantial difference.Strong modifications occur in the SOL [A1.15, A1.17] with respect to the standard metallic wall conditions.Electron temperature increases by more than ΔTe,SOL~10 eV, due to the strong reduction in deuteriumand impurity recycling together with the low radiation from Li atoms/ions eroded by the walls. When theLLL is inserted inside the vessel, instead, the liquid surface represents a strong localised source of Liatoms/ions, which increases radiation losses in a region that is close to the LLL poloidal location andtoroidally uniform. Figure A1.5 shows a plasma image recorded by a visible CCD camera. The radiation infront of the LLL surface reduces the power flux onto the limiter surface which, in turn, is able to sustainthermal loads exceeding 5 MW/m2 with no damage and no lithium bloom occurring. Thermal analysis withthe ANSYS code together with the interpretation given in the framework of the 2D edge physics codeTECXY [A1.18] support this view. Associated with the low particle recycling, enhanced performanceoperations, near or beyond the Greenwald limit, are easily obtained after lithization in the explored plasmacurrent ranges (Ip=0.5-0.9 MA), with no MHD activity. For Ip=0.5 MA, BT=6T, the density limit(n_

e=2.7×1020 m-3) is 1.7 times higher than after a fresh boronization and a factor of 1.4 higher than the

[A1.6] V. Pericoli–Ridolfini et al., Nucl. Fusion 34, 469-481 (1994)

[A1.7] V. Pericoli–Ridolfini et al., Plasma Phys. Control. Fusion 39, 1115-1128 (1997)

[A1.8] P.L. Andrews and F. Perkins, Phys. Fluids 26, 2537-2545 (1983)

[A1.9] V. Pericoli–Ridolfini et al., Nucl. Fusion 38, 12, 1745-1755 (1998)

[A1.10] G. Calabrò et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at: http://epsppd.epfl.ch/Roma/pdf/P5_077.pdf

[A1.11] R. Cesario et al., Nucl. Fusion 46, 462-476 (2006)

[A1.12] V.A. Evtikhin et al., Fusion Eng. Des. 56-57, 363-367 (2001)

[A1.13] A. Vertkov et al., Technological aspects of liquid lithium limiter experiment on FTU tokamak, presented at the 24th Symp. on FusionTechnology - SOFT, (Warsaw 2006)

[A1.14] A.G. Alekseyev et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at:http://epsppd.epfl.ch/Roma/pdf/P1_162.pdf

[A1.15] M.L. Apicella et al., First experiments with lithium limiter on FTU, presented at the 17th Inter. Conference on Plasma Surface Interactions- PSI, (Hefei 2006), to appear in J. Nucl. Mater.

[A1.16] G. Mazzitelli et al., Proc. 21st Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/ex_p4-16.pdf

[A1.17] V. Pericoli–Ridolfini et al., Modification of the SOL properties with the liquid lithium limiter in FTU - experiment and transport modeling,presented at the IEA Large Tokamak IA Workshop on Edge Transport in Fusion Plasmas - ETFP (Kraków 2006), to be published inPlasma Phys. Control. Fusion

[A1.18] R. Zagórski and H. Gerhauser, Physica Scripta 70, 2/3, 173 (2004)

11

Fig. A1.5 – Plasma viewed by a visible CCD camera. At the bottom a bright ring

separated from the main toroidal limiter by a darker zone is clearly visible. LLL is

located on the far bottom right, where the glow is most intense

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corresponding Greenwald limit. In this case the electron density profile reaches a very high peakingfactor ne0/<ne>=2.2 [A1.19] (<...> indicates the volume average).

With the LLL well inserted in the SOL, peculiar new regimes are observed at high density(n_

e≥1×1020 m-3) where, without particle fuelling, a spontaneous transition at higher n_

e occurs closeto the Greenwald limit, characterised by peaked density profiles ne0/<ne>2. This phenomenology,well described in [A1.17], is related to the high Li pumping rate that strongly depresses deuteriumand impurity recycling, thus reducing to a great extent the instabilities due to multifacetedasymmetric radiation from the edge (Marfe).

Transport and energy balance analysis was performed with the JETTO code for plasma dischargesat Ip=0.5 MA, ne=0.7×1020 m-3, Bt=6 T after lithization, fresh boronization and with very cleanmetallic walls (e.g., oxygen-free) [A1.20]. An improvement in energy confinement time τE by a factorof 1.3 was found for lithizated and boronized discharges compared to the metallic case, mainly dueto the strong reduction in Ohmic power produced by the lower Zeff. For boronized and lithizateddischarges τE/τITER97L=1.25 was found, which is sensibly larger than the values observed forstandard metallic FTU Ohmic discharges, which range between an average value ofτE/τITER97L=0.92 [A1.21] up to τE/τITER97L=1.1 in the case of very good clean plasma.

During 2006, preliminary operations with the LLL in plasma-heated discharges with LH and ECRHat power levels in the MW range were obtained without any particular problem, but careful analysisis required to gain a full physical and technological understanding of the experimental results.

MHD real-time control experiment

An active automatic system for MHD mode location and feedback control via ECRH power isinstalled on FTU. The system [A1.22, A1.23] is able to identify, in real time, mode presence/locationand the position of ECRH absorption, and to proceed to suppress the mode.

The aims of the 2006 campaign were i) to look for a more efficient m=2 mode stabilisation obtainedby modulating the ECRH source in phase with the island rotation and ii) to optimise the techniquefor identifying the ECRH absorption position, by enhancing the signal-to-noise ratio.

An overall experimental time of three days was allocated to the experiment: two during the springcampaign and one during the autumn campaign. Only a preliminary result [A1.24, A1.25] wasobtained for target i) because of the difficulties found in plasma target production (an m=2 modewith rotation frequency less than 3 kHz): an MHD mode together with availability of the active ECRHsystem occurred only in a few shots, which were used to optimise the experimental setup. Variousinduced MHD production schemes and a Mo laser blow-off technique were tested. Theachievement of a reliable target is still an open question in the experimental programme, anddedicated experiments should be planned. Further investigation is needed in order to close thecontrol loop and complete the experiment.

Regarding target ii), new modulation schemes were developed, using non-periodic ECRHmodulation, to get a more enhanced signal-to-noise ratio and a better picking factor than with theusual fixed frequency modulation scheme. A partial power scan was performed, but a lowerdetectable power limit has still to be found [A1.26].

Electron cyclotron current drive experiment

The aim of the experiment was to explore at full EC power (1.5 MW) the capability of electroncyclotron current drive (ECCD) to modify the plasma current profile. Modifications would allowcontrol of plasma core confinement and MHD instabilities (e.g., sawteeth) at ITER-relevant plasmadensity n (n=0.6–0.7×1020 m-3) and magnetic field (BT=4.6–5.1 T).



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The immediate goal was to fix the minor radius range where local re-shaping of the plasma current densityand safety factor q profiles can be modified by driving, with oblique injection of EC waves, well localisedECCD in co-/counter- directions (co, to reduce q, counter, to increase it). In the previous 2005 campaignsthe range of minor radius was explored up to r/a=0.3, using 75% of the available EC power (1.1 MW).Significant non-inductive current for plasma current density re-shaping was obtained (6-7% Ip), andsawtooth stabilisation effects by local tailoring were observed by driving counter-current on-axis (±10°) intarget plasmas with Ip=360 kA, <ne>=0.75×1020 m-3 and Te=5 keV [A1.27].

In June 2006 one day of ECCD experiments (eight successful shots), with the same plasma conditions asin 2005, allowed better investigation of the radial range, stabilisation of sawteeth also at ±20° oblique ECinjection, still using 75% of EC power. The goal to control the plasma current density in the plasma core,using two oblique injection angles (±10°–±20°), was achieved even though the ECCD was low (<10% Ip),and linear extrapolations to full EC power with ITER magnetic field and plasma electron density values werecarried out. Moreover, no significant loop voltage changes were observed.

Disruption studies

Plasma disruptions represent a serious issue in tokamak operationand avoidance methods are actively studied, especially in view oftheir application to future experimental reactors (ITER). Experimentson disruption avoidance with ECRH were carried out in FTU duringthe 2006 experimental campaign. The ECRH power PECRH wastriggered at the onset of a disruption, as indicated by the loopvoltage Vloop exceeding a preset value. Disruptions were inducedby impurity injection (Mo) or by raising the electron density abovethe Greenwald limit by using gas puffing. An example of a Mo-injection disruption is shown in figure A1.6. A detailed scan ofPECRH deposition showed that when the power is deposited on therational surfaces relevant for MHD activity, the current quench timeis delayed or the disruption is completely avoided. Figure A1.7shows the delay between the disruption tdis and the beginning ofthe MHD activity tMHD as a function of the PECRH deposition radiusrdep [A1.28].

[A1.19] O. Tudisco et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at: http://epsppd.epfl.ch/Roma/pdf/P5_072.pdf

[A1.20] M.L. Apicella et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at:http: //epsppd.epfl.ch/Roma/pdf/ D5_023.pdf

[A1.21] B. Esposito et al., Fusion Sci. Technol. 45, 297-520 (2004)

[A1.22] J. Berrino et al., IEEE Trans. Nucl. Sci. 53, 1009-1014 (2006)

[A1.23] J. Berrino et al., Fusion Eng. Des. 81, 1917-1921 (2006)

[A1.24] S. Cirant et al., Dynamic control of the current density profile and MHD instabilities by ECH/ECCD in tokamaks, presented at the 14th

Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (Santorini island 2006), paper 75

[A1.25] E. Lazzaro et al., Proc. Inter. Workshop on Strong Microwaves in Plasmas (Nyzhny Novgorod 2006), Russian Academy of Sciences,Institute Applied Physics, Vol. 2, 524 (2006)

[A1.26] F. Gandini et al., Proc. 21st IAEA Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/EX_P8-6.pdf

[A1.27] S. Nowak et al., Proc. 32nd EPS Conference on Plasma Physics (Tarragona 2005), on line at:http://epsppd.epfl.ch/Tarragona/pdf/P1_095.pdf

[A1.28] B. Esposito et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at: http://epsppd.epfl.ch/Roma/pdf/P5_071.pdf

13

Time (s)0.7 0.9 1.1P

EC

RH

(MW

)T

e0(k

eV)

I p(M

A)

Neu

tron

s (n

/s)

MH

D (

arb.

units

)0

0.8

0.4

0

0.2

0.4

4×105

2×105

1011

109

0

0

1

2

29484 (ECRH)

29473 (no ECRH)

Fig. A1.6 – Comparison of time traces of plasma current Ip, central electron

temperature Te0, MHD activity, neutron rate and PECRH in two discharges

(#29484: PECRH=1.1 MW and #29473: no ECRH) in which Mo is injected at t=0.8 s

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Another important issue is the effect of LHpower on disruptions. The formation of largerunaway electron currents (fig. A1.8) has beenfound to occur more often in FTU in dischargesthat disrupt during LH injection. Contrary to thetheoretical expectations for electron thermalrunaway generation (based on the usualDreicer and avalanche mechanisms), thelargest runaway currents correspond to theslowest plasma current decay rates (fig. A1.9).This trend is opposite to what is observed inmost tokamaks. Such anomalous behaviour is

attributed to pre-existent wave-resonant suprathermal electrons being accelerated during thedisruption decay phase [A1.29]. These results could be relevant for the operation of ITER whenevera sizeable amount of LH power is used.

Dusty plasmas

Research on the problem of dust in tokamak plasmas is carried out in the framework of acollaboration with the universities of Naples and Molise and the Max Planck Institute forExtraterrestrial Studies. Interest in this subject is increasing due its relevance for fusion reactors interms of safety and operation [A1.30].

Preliminary theoretical studies were dedicated to analysing, in un-magnetised dusty plasmas,fundamental dust interactions and fluctuations. In the framework of linear, fluid theory, it was shownthat over-screening and attraction between negatively charged dust particles can occur if cationsare released by the dust surface [A1.31]. Problems associated with a full kinetic model of such dustinteraction were discussed and solved in principle, although analytical calculations still have to becompleted [A1.32]. The kinetic theory of fluctuations was used to describe changes in the spectraldensities of plasma fluctuations in un-magnetised plasmas in the presence of dust [A1.33].



# 29979 & # 29963

q=3/2 q=2q=3

disruptionavoidance

0

40

80

0 10 20

t dis

-tM

HD

(ms)

rdep (cm)

# 29984

q=1

n/s

I p(M

A)

VI(V

)0.4

0.2

0

1013

1011

80

40

0

1.00 1.02 1.04 1.06 1.08Time (s)

19989

a)

b)

NE213BF3

Ip

VI

Fig. A1.8 – Plasma disruption showing the formation of a

0.3–MA runaway current: a) plasma current Ip (solid) and

loop voltage Vloop (dashed); b) neutron rate: BF3 (solid)

and NE213 (dashed) signals. The NE213 line is absent

during the plateau phase because of saturation

Fig. A1.7 – PECRH deposition scan: safety factor (q) values obtained from island viewed

through soft-x-ray tomography (except for q=1 determined from sawtooth inversion radius)l/l

p(%

)

(dlp/dt)max(MA/s)

80

40

0

0 40 80 120 160

LH -500 kAOH-500 kA

LH - 350 kAOH- 300 - 400 kA

500 kA;Te =42 eV

350 kA;Te =44 eV

350 kA;T

e =80 eV

Fig. A1.9 – Runaway current fraction vs maximum

plasma current derivative during current quench for LH

runaway plateau disruptions. Ohmic runaway plateau

disruptions included for comparison

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Experimental analysis of scattered laser light signals in FTUdischarges during disruption events confirmed the presence ofdust particles [A1.34], formerly observed by this kind ofdiagnostic in JIPPT-IIU [A1.35]. Laser scattering signals wereobserved by the Thomson scattering (TS) system installed inFTU. The spectral transmission of the filter of the spectral channelused for alignment has been centred at the laser wavelength sothat it can reveal elastic light scattering, which might be due tothe presence of dust particles [A1.35]. Elastic scatteringobserved in several discharges after a disruption can last morethan 1 s after the end of the discharges. Preliminary analysis ofthe laser light scattering data suggests the presence, after adisruption, of sub-micron size (<0.1 μm) dust particles.

Experiments to see if dust could be detected during the plasma discharge were carried out with the useof electrostatic probes. Low plasma density discharges (ne=4×1019 m-3, Ip=0.35 MA, at BT=7.0 T) werechosen to maximise the effect of dust on the probe signal. Statistical analysis of fluctuations of the ionsaturation current collected by the probes in the equatorial plane revealed that the occurrence of a numberof large spikes, similar to those reported in the majority of works on SOL transport studies as a signatureof plasma structures ("coherent structures", "avalanches", "blobs”, see e.g. [A1.36]), cannot be due topropagating phenomena, but can be ascribed to a local interaction. The e-folding time of theautocorrelation function decreases towards the wall, from 100 μs at the position r1=32.5 cm to 35 μs atr2=33.1 cm. Such behaviour is opposite to what one would expect from the deceleration of radiallyadvected filamentary structures, which yields a radially increasing autocorrelation time. The maximum ofthe cross-correlation function of the signals from two poloidally separated equatorial probes does notexceed 0.33 at position r1, falling to 0.25 towards the wall. Such a weak correlation suggests that thesignal observed is not due only to propagating structures, because the separation between the probes is0.6 cm and the typical structures of edge turbulence are reported to be in excess of 1 cm [A1.37]. In fact,a closer look at the signals shows that there is no correlation between big events “seen” by probes;whenever one of the probes measures a large signal, namely with deviation from the average value equalto a few times the standard deviation (rms), the other probe does not show any particular “response”. Thisis true for all three radial positions investigated. To support such an observation statistically, theconditionally averaged waveforms measured by two probes for different thresholds were calculated. Theresults show that with increasing the threshold (up to 8 rms), the difference between signals on two probesincreases up to about one order of magnitude and no clear time shift can be identified (fig. A1.10).Filamentary structures of larger amplitude, on the other hand, are characterised by larger poloidalcorrelation length [A1.37]. The observed interaction is shown to be in quantitative agreement only with theionization, and the consequent extra charge (of the order of 1011 elementary charges) collected by the

[A1.29] J.R. Martın-Solıs et al., Phys. Rev. Lett. 97, 165002 (2006)

[A1.30] G. Federici et al., Nucl. Fusion 41, 1967 (2001)

[A1.31] C. Castaldo, U. De Angelis, V.N. Tsytovich, Phys. Rev. Lett. 96, 075004 (2006)

[A1.32] C. Castaldo, U. De Angelis, V.N. Tsytovich, Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at:http://epsppd.epfl.ch/Roma/pdf/O2_020.pdf

[A1.33] U. De Angelis et al., Plasma Phys. Control. Fusion 48, B91 (2006)

[A1.34] E. Giovannozzi, C. Castaldo, G. Maddaluno, Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at:http://epsppd.epfl.ch/Roma/pdf/P2_093.pdf

[A1.35] K. Narihara et al., Nucl. Fusion 37, 1177 (1997)

[A1.36] G.Y. Antar et al., Phys. Plasmas 8, 1612 (2001)

[A1.37] S.J. Zweben et al, Phys. Plasmas 9, 1981 (2002)

15

CA

sig

nals

(m

s) 4

3

2

1

80 160 240

a)Fig. A1.10 – Conditionally averaged signals with

threshold of 4 a) and 8 rms b). Number of elementary

charges collected during typical large event (inset in b)

CA

sig

nals

(m

s)

Time (μs)

Time (μs)4

6

2

10

84

3

1

0

2

20 40 60 80

80 160 240

b)Ni/1011

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probes, due to the impact of μm-sizeddust at a velocity of the order of ten km/s.This interpretation is supported directlyby electron microscope analysis of theprobe surface, which revealed thepresence of 10 to 100–μm–sized craters,a typical footprint of the impact ionizationprocesses (fig. A1.11). A number ofspherically shaped, iron-rich μm-sizedparticles was also observed to beembedded in the probe surface. Neithercraters nor embedded particles weredetected on the surface of the “virgin”probe. The size, number and distributionof the observed craters are consistentwith impact ionization processesoccurring at an average rate of a fewhundred Hz, which corresponds to104 m-3 density of fast μm–sized dust

particles accelerated at velocities of the order of 10 km/s by ion drag forces associated with plasmaflows in the SOL of FTU.

A1.4 Plasma Theory

Mutual and positive feedbacks between theory and experiments have led to a clear identification ofhigh-frequency MHD activity (high frequency with respect to that typical of MHD fluctuations) in FTUas evidence of nonlinear Alfvén mode excitations by a large magnetic island.

Electron-fishbone mode excitations by LH additional power only are explained within a generaltheoretical framework, which fully accounts for the various experimental evidence of such modesand also provides a simple yet relevant model for interpreting the rich nonlinear dynamic behaviour,observed experimentally.

The theory of propagation and absorption of rf waves in toroidal plasmas has been explored in bothits more basic aspects as well as with detailed applications of practical relevance, such as themodelling of ICRH experiments in JET and the investigation of burning plasma dynamics issues byICRH accelerated minority ion supra-thermal tails.

The investigation of energetic ion dynamics in burning plasmas has been articulated along threemain lines: i) identification of the relevant plasma parameters that make it possible to experimentallystudy burning plasma physics issues in sub-ignited regimes; ii) numerical simulation of energetic iontransport and nonlinear Alfvénic fluctuations in situations of experimental relevance in present-dayexperiments; iii) first-principle-based analysis of fundamental processes involved in the collectiveexcitation of Alfvénic modes and in the fluctuation enhanced energetic ion transport. Item ii) hasbeen explored with the interpretation of nonlinear Alfvén wave dynamics and energetic ion transportobserved in JT-60U by means of hybrid MHD-gyrokinetic numerical simulations, carried out withinan ongoing collaboration with the Japan Atomic Energy Agency. For item iii) an overview of thetheory of Alfvén waves and energetic particle physics in burning plasmas has been given as a resultof work done within the continuing collaboration with University of California at Irvine (UCI) USA.

Within the same framework of UCI collaboration, recent theoretical work on plasma turbulence andturbulent transport, or more specifically, on nonlinear equilibria, stability and generation of zonalstructures in toroidal plasmas has been summarised.



Fig. A1.11 – Electron microscope analysis of the probe

surface

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Theory of beta-induced Alfvén-eigenmodes

Beta-induced Alfvén eigenmodes (BAEs) have frequency located in the low-frequency beta-induced gap inthe shear-Alfvén continuous spectrum, which is caused by finite plasma compressibility [A1.38-A1.40].Their excitation can be due to the presence of fast ions and/or sharp thermal ion temperature gradients.However recent observations in FTU [A1.41, A1.42], TEXTOR [A1.43] and JET have revealed the presenceof modes whose frequency is consistent with that of BAEs, coexisting with a large magnetic island, in theabsence of fast ions and without direct thermal ion heating. In this framework, the magnetic island appearsto play a causal role in the excitation of modes at BAE frequencies.

A kinetic stability analysis [A1.40, A1.44] of BAEs, including the effects of finite Larmor radius, finite orbitwidth and toroidicity, led to a dispersion relation for BAE modes, obtained by asymptotically matching thekinetic layer solution with that of the ideal MHD region. The resulting frequencies compare very well withthose seen experimentally in FTU [A1.45], so it can concluded that the modes observed are BAEs.Moreover, their calculated growth rates (the experimental ones cannot be measured) are negative but smallin absolute value compared to their frequencies, so it can be inferred that such modes are marginally stableand become nonlinearly excited above a critical amplitude threshold of the magnetic island. Analysis ofBAE destabilisation by a finite amplitude magnetic island is in progress.

Electron fishbones: theory and experimental evidence

The work described here was done in collaboration with UCI and the South-western Institute of Physics,Chengdu P.R.C. Fishbone-like internal kink instabilities driven by electrons in conjunction with ECRH on thehigh-field side were observed for the first time on DIII-D [A1.46]. The excitation was attributed to barelytrapped supra-thermal electrons, which are characterised by drift-reversal and can destabilise a modepropagating in the ion diamagnetic direction in the presence of an inverted spatial gradient of the supra-thermal tail. Similar but higher frequency modes were observed in Compass-D [A1.47] during ECRH andLH power injection, with chirping frequency comparable to that of the toroidal Alfvén eigenmode (TAE),[A1.48] ω≤ωTAE. Observations of electron fishbones with ECRH only [A1.49, A1.50] and LH only [A1.51,A1.52] have also been reported in HL-1M and FTU, respectively.

[A1.38] W.W. Heidbrink et al., Phys. Rev. Lett. 71, 855 (1993)

[A1.39] A.D. Turnbull et al., Phys. Fluids B5, 2546 (1993)

[A1.40] F. Zonca, L. Chen and R.A. Santoro, Plasma Phys. Control. Fusion 38, 2011 (1996)

[A1.41] P. Buratti et al., Nucl. Fusion 45, 1446 (2005)

[A1.42] P. Buratti et al., Proc. 32nd EPS Conference on Plasma Physics (Tarragona 2005), on line at:http: //epsppd.epfl.ch/Tarragona/pdf/P5_055.pdf

[A1.43] O. Zimmermann et al., Proc. 32nd EPS Conference on Plasma Physics (Tarragona 2005), on line at:http: //epsppd.epfl.ch/Tarragona/pdf/P4_059.pdf

[A1.44] F. Zonca et al., Plasma Phys. Control. Fusion 40, 2009 (1998)

[A1.45] S.V. Annibaldi, F. Zonca and P. Buratti, Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at:http://epsppd.epfl.ch/Roma/pdf/ O2_016.pdf, and to appear on Plasma Phys. Control. Fusion

[A1.46] K.L. Wong et al., Phys. Rev. Lett. 85, 996 (2000)

[A1.47] M. Valovic et al., Nucl. Fusion 40, 1569 (2000)

[A1.48] C.Z. Cheng, L. Chen and M.S. Chance, Ann. Phys. 161, 21 (1985)

[A1.49] X.T. Ding et al., Nucl. Fusion 42, 491 (2002)

[A1.50] J. Li et al., Proc. 19th IAEA Fusion Energy Conference (Lyon 2002), on line at: http://www-pub.iaea.org/MTCD/publications/PDF/csp_019c/pdf/OV_5-1.pdf

[A1.51] P. Smeulders et al., Proc. of the 29th EPS Conference on Plasma Physics and Controlled Fusion (Montreaux 2002), on line at:http://epsppd.epfl.ch/Montreux/pdf/D5_016.pdf

[A1.52] F. Romanelli et al., Proc. 19th IAEA Fusion Energy Conf. (Lyon 2002), on line at: http://www-pub.iaea.org/MTCD/publications/PDF/csp_019c/pdf/OV_4-5.pdf

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The peculiar features of electron fishbones wereanalysed vs those of the well-known ion fishbone[A1.53-A1.55]. Due to the frequency gap in the low-frequency shear Alfvén continuum for modespropagating in the ion diamagnetic direction[A1.55], effective electron fishbone excitation

favours conditions characterised by supra-thermal electron drift reversal, which is consistent withexperimental observations. For the same reason, the spatial gradient inversion of the supra-thermalelectron tail is necessary, explaining why ECRH excitation is observed with high-field side depositiononly [A1.46, A1.49, A1.50, A1.56]. Circulating supra-thermal electrons play a peculiar role in electronfishbone excitations with LH only: the barely circulating population directly provides the mode driveand the well circulating particles controls the drift-reversal condition. As in the case of ion fishbones,two branches of the electron fishbone have been shown to exist: a discrete gap mode [A1.55] anda continuum resonant mode [A1.54]. Contrary to the gap mode, the continuum resonant mode canpropagate in the electron diamagnetic direction as well. Thus, it does not require either drift-reversalor inverted spatial gradient of the supra-thermal electron tail. However, its threshold condition ishigher and it requires high power densities to be excited. So, even the case of the continuumresonant fishbone mode tends to favour the branch propagating in the ion diamagnetic direction,which minimises continuum damping. If the effective temperature of the supra-thermal electron tailis sufficiently high, the present theory predicts that fishbone oscillations can be excited atfrequencies comparable with those typical of the geodesic acoustic mode (GAM) [A1.57] or the BAE[A1.38, A1.39]. Unlike the case of fishbone gap modes in the ion diamagnetic gap [A1.55] of thelow-frequency shear Alfvén continuum, fishbone gap modes in the BAE gap [A1.58] do not favourpropagation in the ion diamagnetic direction, since the gap structure is nearly symmetric infrequency [A1.40]. One single general fishbone-like dispersion relation [A1.59] has been discussed,describing mode excitation by trapped as well as circulating supra-thermal electrons in bothmonotonic and reversed magnetic shear equilibria [A1.60].

The most interesting feature of electron fishbones is their relevance to burning plasmas. In fact,unlike fast ions in present-day experiments, fast electrons are characterised by small orbits that donot introduce additional complications in the physics due to nonlocal behaviour, similarly to alphaparticles in reactor-relevant conditions. Meanwhile, the bounce averaged dynamics of both trappedas well as barely circulating electrons depends on energy (not mass); hence their effect on low-frequency MHD modes can be used to simulate/analyse the analogous effect of charged fusionproducts. Furthermore, the combined use of ECRH and LH provides extremely flexible tools toinvestigate diverse nonlinear behaviour, for which FTU experimental results provide a nice and clearexample (fig. A1.12). During high-power LH injection, an evident transition in the electron fishbonesignature takes place from almost steady-state nonlinear oscillations (fixed point) to regular burstybehaviour (limit cycle). A simple yet relevant nonlinear dynamic model has been derived forpredicting and interpreting these observations [A1.61].

Analysis and modelling of LHW propagation in toroidal plasmas by asymptoticmethods

The LH full wave equation in the electrostatic approximation and in general magnetic field equilibriahas beenen critically analysed by applying asymptotic techniques when looking for the solution(Wenzel, Kramer, Brillouin [WKB] approximation). The phase and the amplitude were obtainednumerically and analytically, and then compared [A1.62].



8642

0.60.5

0.41.51.00.5

0

0-0.5

-10.25 0.30 0.350.20 0.40

keV

MW

1020

m-3

keV

Time (s)

1st branch 2nd branch ECE Ch 9

Te0ne,line

PLH

1)

2)

3)

4)

Fig. A1.12 – Time evolution of thermal electron temperature 1),

electron density 2), LH power input 3) and (fast) electron

temperature fluctuation 4) in FTU shot #20865. It is clear that

the nonlinear behaviour of electron temperature fluctuations

(electron fishbone) reflects the level of LH power input

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Lower hybrid wave (LHW) propagation in a tokamak plasma 2D geometry can be correctly described onlywith a full wave approach based on full numerical techniques or on a semi-analytical approach, by reducingthe wave equation into two nested equations of the first order, as shown in [A1.63]. To test and comparethe full numerical solution with that obtained by applying the WKB asymptotic expansion, a rigorous WKBsolution of the wave equation for the first two orders of the expansion parameter was presented, obtaining,at the first order, the equation for phase and, at the next order, the equation for the field amplitude. Thenonlinear partial differential equation (PDE) for the phase was solved in a pseudo-toroidal geometry (circularand concentric magnetic surfaces) by the method of characteristics. The associated system of ordinarydifferential equations (ODEs) for the position and the wave-number was obtained and analytically solvedby choosing an appropriate expansion parameter. The quasi-linear PDE for the WKB amplitude was alsoanalytically solved, allowing reconstruction of the wave electric field inside the plasma. The solution wasalso obtained numerically and compared with the analytical solution. Further developments, consisting ingeneralising the solution to a Solov’ev analytical equilibrium geometry, are in progress. The validity of theWKB approximation was analysed on the basis of the results obtained.

Modelling of the ICRH experiment on JET

The aims of this modelling study are first to evaluate the main features of the proposed ICRH heatingexperiment and second to perform a detailed analysis of the experimental discharges. The proposedexperiment concerns essentially the possibility of obtaining internal transport barriers (ITBs) on both the ionand the electrons species with only the use of the ICRH system in an ion-heating scheme, without neutralbeam injection (NBI) as an external momentum input. In this context an ITB regime on JET was obtainedby using 6 MW of ICRH in the minority heating scheme [A1.64].

The minority species involved is 3He. The scheme should act at the fundamental cyclotron harmonic of theminority species (ω=Ωcm) located near the plasma centre, while the fundamental or the first harmonic ofthe majority (ω=ΩcM or ω=2ΩcM) is out of the plasma. This is the so-called isolated case. Cyclotronresonance heating of the minority is very efficient because fast wave polarization is essentially determinedby the majority species alone, while damping is due essentially to the resonant minority ions (minorityheating regime). If the minority concentration increases too much, the screening due to the rotating electricfield is no longer negligible, and cyclotron damping decreases drastically, entering the “mode conversionregime”.

When programming an ICRH heating experiment, it is important to establish the plasma and antennaparameters that fit the goals well. In the ICRH minority heating experiment on JET, antenna and plasmaparameters are chosen by maximising the power coupled to the plasma, without dealing with edge

[A1.53] K. McGuire et al., Phys. Rev. Lett. 50, 891 (1983)

[A1.54] L. Chen, R.B. White and M.N. Rosenbluth, Phys. Rev. Lett. 52, 1122 (1984)

[A1.55] B. Coppi and F. Porcelli, Phys. Rev. Lett. 57, 2272 (1986)

[A1.56] Z.-T. Wang et al., Chin. Phys. Lett. 23, 158 (2006)

[A1.57] N. Winsor, J.L. Johnson and J.M. Dawson, Phys. Fluids 11, 2448 (1968)

[A1.58] M.S. Chu et al., Phys. Fluids B4, 3713 (1992)

[A1.59] F. Zonca and L. Chen, Plasma Phys. Control. Fusion 48, 537 (2006)

[A1.60] R.J. Hastie et al., Phys. Fluids 30, 1756 (1987)

[A1.61] F. Zonca et al., Electron fishbones: theory and experimental evidence, submitted to Nucl. Fusion

[A1.62] A. Cardinali, L. Morini and F. Zonca, Proc. of the Joint Varenna-Lausanne International Workshop on Theory of Fusion Plasmas, ed. byJ. Connor, O. Sauter, E. Sindoni (American Institute of Physics, Varenna), Vol. 871, 292 (2006)

[A1.63] A. Cardinali and F. Zonca, Phys. Plasmas 10, 4199 (2003)

[A1.64] F. Crisanti et al., Experimental evidence of ion internal transport barrier without injection of external momentum input, presented at theTransport Task Force Meeting (Varenna 2004)

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cut–offs in the low field side, and by choosing the right minority concentration in order to avoid themode conversion regime [A1.65].

The following codes have been used to plan and to model the ICRH experiment:

1) A code that solves the cold plasma electromagnetic (em) dispersion relation in slab geometry inorder to clarify the dispersion characteristics of the experiment. Thus, the range of variation inthe main parameters can be established, e.g., power spectrum vs plasma density profiles toassess the accessibility conditions; minority concentration to assess, in a plasma with two ionspecies (or more), the localisation of the ion-ion resonance (and the associated cut-off), whichturns out to be very close to the ion cyclotron resonance of the minority species, etc.

2) A code that solves the warm plasma em dispersion relation in the complex space of the wave-number in order to clarify the effect of wave damping on the minority species, the effects of theplasma parameters (minority concentration, ion and electron temperature, parallel wave-number)on the transition to the mode conversion regime. The use of this code should also provide thepower deposition profiles and the power damping rate for the entire launched spectrum.

3) A 1D ray-tracing code in cylindrical geometry to take into account, at the lowest order, thegeometry of the tokamak plasma. The code uses the warm plasma em dispersion relation ofpoint 2).

4) When needed, a complex 2D ray-tracing code in tokamak geometry to take into account therealistic geometry of the tokamak. This code is based on a complex full em dispersion relationand complex integration of the trajectories.

5) A 1D full wave code (FELICE), which gives the linear distribution of the wave power on ion andelectron species. It accounts correctly for the electron Landau damping (ELD) in the fast wavebranch and in the ion Bernstein wave (IBW) branch; it also accounts for the realistic antenna-plasma coupling and calculates the whole effect of the power spectrum on the various species.

6) A 2D full wave code (TORIC) [A1.66], which has the same characteristics as the 1D FELICEcode, but includes the real geometry of the plasma (in the flux surface coordinate system).

7) A 2D full wave code (steady-state quasi-linear Fokker-Planck [SSQLFP] code), which does thesame as before but includes the evolution of the 2D distribution function for the ions andelectrons.

Simulation of burning plasma dynamics by ICRH accelerated minority ions

The main difference between present experiments and ITER will be the presence, as the mainheating source, of alpha-particles produced in DT reactions. Alpha particles will mainly heatelectrons, contrary to present experiments dominated by low-energy neutral beam injection thatmainly heats the ions. Moreover, alpha-particles can drive stronger collective modes.

As proposed in [A1.67], alpha-particle dynamics can be simulated in pure deuterium plasmas byions accelerated by rf waves. The use of ICRH in the minority scheme (H or 3He) can indeedproduce fast particles (although with a different distribution function to that of fusion-generatedalpha-particles) which, with an appropriate choice of the minority concentration, rf power andplasma density and temperature, can reproduce the dimensionless parameters ρ

*fast and βfastcharacterising the alpha-particles in ITER. Here, ρ

*fast is the normalised fast-particle radius and βfastthe fast-particle beta. Thus, a device operating with deuterium plasmas in a dimensionlessparameter range as close as possible to that of ITER and equipped with ICRH as the main heatingscheme would allow investigation of some of the most important features of alpha-particle heatedplasmas and, therefore, it would be possible to assess these issues in relevant scenarios before theirimplementation on ITER itself.

As an example, the following reference antenna and plasma parameters were considered: 24 MWof ICRH power coupled to the plasma at a frequency f=81 MHz; toroidal magnetic field BT=8T;volume average density <ne>=4×1020 m-3 with generalised parabolic profile (1-(r2/a2))α and 3He



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minority-heating scheme. Two scenarios were taken into account:one characterised by the enhancement factor H=1.3, consistent withan ITB and peaked profiles (αn=1 αT=1), which corresponds tohaving βN=1.8% and on-axis values of density, temperature and betagiven by, respectively, ne0=6×1020 m-3, Te0=Ti0=12 keV; the othercharacterised by an enhancement factor H=1, in H-mode, and flatprofiles αn=0 αT=1, with βN=1.4%, and ne0=4×1020 m-3,Te0=Ti0=10 keV. A parametric study of ICRH absorption wasperformed, varying the resonant layer, coupled wave spectrum,minority concentration, density and temperature, with the aim ofincreasing the power coupled to the minority ions and obtaining themaximum effective temperature of the tail. As an example, the resultsobtained in the “enhanced H-mode scenario” are reported here. Infigure A1.13, the power density coupled to the various species in(W/cm3) is plotted vs the plasma radius, when an optimum 3Heminority concentration of 2% (which maximises the power absorbedby the minority) is considered. From the figure it is possible to get thelocalisation of the deposition, r/a=0.1 the width of the depositionlayer, Δr/a=0.2 for the minority and broader for the electrons, and thepeak of the power density (45 Watt/cm3).

The quasi-linear analysis, based on the linear results shown above,allows calculation of the effective temperature of the minority ions aswell as the fraction of the minority at those energies. The effectivetemperature was calculated to be ≈150 keV (on the peak of theabsorption layer), with a fast ion fraction of about 30% leading to afast ion βfast of about 0.8%. Figure A1.14 shows the effectivetemperature of the ion minority in parallel and perpendiculardirections as a function of the plasma radius.

Particle simulation of bursting Alfvénmodes in JT–60U

A numerical investigation, based on particle-in-cellsimulations, of the bursting-mode phenomenologyobserved in negative neutral beam (NNB)-heatedJT–60U discharges was performed [A1.68– A1.70]. Itwas shown that the experimental observations can beinterpreted as the effect of nonlinear interactionbetween Alfvén modes and the energetic ionsproduced by NNB injection. In particular, the

[A1.65] A. Cardinali et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at:http://epsppd.epfl.ch/Roma/pdf/P1_065.pdf

[A1.66] M. Brambilla, Plasma Phys. Control. Fusion 41, 1 (1999)

[A1.67] F. Romanelli et al., Fusion Sci. Technol. 45, 483 (2004)

[A1.68] G. Vlad et al., Proc. of the Joint Varenna-Lausanne International Workshop on Theory of Fusion Plasmas, ed. by J. Connor, O. Sauter,E. Sindoni (American Institute of Physics, Varenna), Vol. 871, 250-263 (2006)

[A1.69] G. Vlad et al., Proc. 21st IAEA Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/TH_P6-4.pdf

[A1.70] S. Briguglio et al., Particle simulation of bursting Alfvén modes in JT-60U, accepted for publication in Phys. Plasmas

21

b3

60

40

20

00 0.2 0.4 0.6 0.8 1

r/a

Total ICRH power densityPower to ionPower to electrons

Fig. A1.13 – Power deposition profiles vs plasma radius for

the various species

keV

150

100

50

00 0.2 0.4 0.6 0.8 1

r/a

Teff, perp

Teff, par

Fig. A1.14 – Effective temperature of the

minority vs plasma radius

0.0

0.2

0.4

0.6

0.8

1.0

0.0 0.2 0.4 0.6 0.8 1.0r/a

Initial

After ALE

Relaxed

n H/n

H0

Fig. A1.15 – Nonlinear modifications of the energetic ion density

profile produced by EPM saturation. Blue curve: initial (simulation

and experimental) profile. Red curve: relaxed profile obtained in the

simulation. Black curve: experimentally inferred profile just after the

ALE occurrence, plotted here for comparison

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investigation, related to modes with toroidalnumber n=1, showed that an energetic particlemode (EPM) localised around the maximum ofthe energetic-ion pressure gradient is drivenunstable by resonant interaction with such ions.Its saturation produces radial displacement ofenergetic ions, in fair agreement with theexperimental findings related to the so-calledabrupt-large-amplitude events (ALEs)(fig. A1.15).

Simulation results demonstrate that displacedions resonate with Alfvén modes in the outerregion (fig. A1.16), causing a TAE-like mode tobecome dominant as the saturation of the EPMproceeds. It has also been observed that thescattering due to the EPM is more effective onresonant ions than non-resonant. Besides therelaxation of the density profile, a distortion inthe velocity-space distribution function is thenproduced (fig. A1.17). This fact can explain why

a quieter phase, characterised by weaker bursting modes (the fast frequency sweeping), isobserved after an ALE, allowing the system to restore the free energy needed for a new ALE. In theabsence of velocity-space distortion, any reconstruction of the density profile would indeed generaterelatively large amplitude modes: energetic ions would be further scattered by these modes andtheir density profile would be essentially clamped to the relaxed profile produced by the ALE.

Once the phase-space distortion is fully taken into account, the free-energy reconstruction rate isinstead set by the need to rebuild both the density profile and the resonant part of the distributionfunction. The slow time scale evolution of energetic ion equilibria in intermediate configurationsbetween two successive ALEs is then characterised by a lower drive than that corresponding to theunperturbed velocity-space distribution function, and the weak modes excited are less effective incontrasting the density profile reconstruction. Only when the combined restoration of theconfiguration and velocity space distributions provides enough drive for a fast growing Alfvén mode,does a new ALE occur.



a)

0 0.25 0.5 0.75 10

1

2

3

Ê

α

0 0.25 0.5 0.75 10

1

2

3

Ê

α

b)

0 0.25 0.5 0.75 10

1

2

3

Ê

α

c)

Fig. A1.16 – a) Variation in the energetic-ion distribution function in the (Ê,α) plane (Ê being the energy, α the pitch-

angle of the energetic ions), after saturation of the EPM, averaged on the outer plasma region, where the TAE-like

mode grows. b) Volume average of the power transfer from particles to the wave (i.e., the resonance pattern), in the

same region, during the linear simulation stage. c) Power transfer after EPM saturation. Red corresponds to positive

values; violet to negative. The EPM saturation causes an increase in the energetic-ion distribution function at low

energy and large pitch-angle. It can be shown that the increase is due to an outward radial displacement from the

central (EPM) region. The displaced ions resonate with the outer mode, modifying the outer resonance

E^

α

F-FSD^ ^

0.0040.0030.0020.001

0

-0.004-0.003-0.002-0.001

32

1

2.51.5

0.50

0.20.4

0.60.8

1

Fig. A1.17 – Distortion with respect to the slowing

down distribution function (F^-F^

SD) of the energetic-ion

distribution function in the (Ê,α) plane produced by

EPM saturation

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Theory of Alfvén waves and energetic particle physics in burning plasmas

An overview of the work presented here has been given in [A1.71]. A unique characteristic of burningplasmas is that the energy density of fast ions (MeV energies) and charged fusion products is a significantfraction of the total plasma energy density. Consequently, one can address two major issues of practicalconcern in such plasmas: i) whether fast ions and charged fusion products are sufficiently well confined totransfer their energy and/or momentum to the thermal plasma without appreciable degradation due tocollective modes; and ii) whether, on longer time scales, mutual interactions between collective modes andenergetic ion dynamics on the one hand and drift wave turbulence and turbulent transport on the othermay decrease the overall thermonuclear efficiency of the considered system.

The first issue was addressed by analysing theoretically the dynamics of shear Alfvén waves collectivelyexcited by energetic particles in tokamak plasmas. Both linear physics, such as spectral and stabilityproperties, as well as key nonlinear wave and particle dynamics have been identified and considered. Theinvestigations of such processes via computer simulations have also been discussed along with theimportance of benchmarking with existing or future experimental observations.

In terms of consequences, the two issues have different practical implications: the first has a direct impacton the operation scenarios and boundaries, since energy and momentum fluxes due to collective lossesmay lead to significant wall loading and damage to plasma-facing materials; the second poses soft limitsin the operation space.

In the framework of plasma theory, the first issue is connected with identification of burning plasma stabilityboundaries with respect to collective mode excitations by fast ions and charged fusion products as wellas with nonlinear dynamics above the stability thresholds; the second is associated with long time-scalenonlinear behaviour typical of self-organised complex systems.

Nonlinear equilibria, stability and generation of zonal structures in toroidal plasmas

The crucial role played by zonal flows [A1.72] in regulating the saturation level of drift wave turbulence andultimately of turbulent transport [A1.73] has led to significant attention being paid to determining thequantity of zonal flows (ZFs) that can be spontaneously generated by the turbulence itself before the flowsbecome unstable, also due to Kelvin Helmholtz (KH)–like mode excitations [A1.74-A1.76]. In thisframework, drift waves (DWs) are the “primary” instability and spontaneously generate ZFs, the“secondary” instability, which can be limited in amplitude by the onset of “tertiary” KH–like modes [A1.74-A1.76]. The “tertiary” instability has been proposed to explain the nonlinear up-shift of the critical iontemperature gradient (ITG) driven turbulence threshold [A1.77].

It has been proposed that long-lived saturated ZF structures, spontaneously generated by DW turbulence,can be considered as generators of neighbouring nonlinear equilibria [A1.78]. In the present theoreticalframework, the general form of these neighbouring nonlinear equilibria has been computed in terms of

[A1.71] L. Chen and F. Zonca, Proc. 21st IAEA Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/OV_5-3.pdf, and submitted to Nuclear Fusion

[A1.72] A. Hasegawa et al., Phys. Fluids 22, 2122 (1979)

[A1.73] Z. Lin et al., Science 281, 1835 (1998)

[A1.74] B.N. Rogers et al., Phys. Rev. Lett. 85, 5336 (2000)

[A1.75] F.L. Hinton and M.N. Rosenbluth, Bull. Am. Phys. Soc. 45,7, 195 (2000)

[A1.76] E.-J. Kim and P.H. Diamond, Phys. Plasmas 9, 4530 (2002)

[A1.77] A.M. Dimits et al., Phys. Plasmas 7, 969 (2000)

[A1.78] L. Chen and F. Zonca, Proc. 21st IAEA Fusion Energy Conference (Chengdu 2006), on line at: http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/papers/TH_P2-1.pdf, and submitted to Nucl. Fusion

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zonal structures as well as of the characteristics of the primary DW turbulence. The derived nonlinearevolution equation for the zonal response consistently describes the temporal evolution of the zonalstructures, whose time-asymptotic behaviour corresponds to nonlinear equilibria. The stability of thenonlinear equilibria determines the nature of the “tertiary” instability regime, the nonlinear up-shift ofcritical thresholds, and the collisionless dissipation of the zonal structures. On a shorter time-scale,the temporal evolution of the zonal response describes the DW-ZF generation and the regulation ofthe DW intensity by the ZFs.

While the stability properties of the nonlinear zonal equilibria have been given in terms of integraleigenmode equations [A1.75], simple estimates for the threshold condition for tertiary instability canbe derived in the local limit. It has also been discussed how this instability condition can betranslated into an estimate of the nonlinear up-shift of the critical threshold for the ITG turbulencedriven transport, known as the “Dimits-shift” [A1.77]. In fact, employing the time asymptoticresponse of the zonal structures as the nonlinear equilibria allows one to directly connect the startingreference equilibrium quantities to the nonlinear equilibrium features due to finite ZF amplitude as,e.g., radial modulations in the temperature profile [A1.79]. It has been shown that tertiary instabilityconsists of trapped ion ITG modes (TITG), generated by these radial modulations of the iontemperature profile. Employing the quasi-linear description, it is has been further demonstrated thattertiary TITG turbulence [A1.78] can lead to collisionless dissipations of the zonal structures, i.e.,their quasi-linear relaxations. In this respect, the existence of TITG turbulence can then lead to theresurgence of the primary DW turbulence and of turbulent transport, which is strongly suppressedby ZFs for reference plasma equilibrium gradients below the Dimits-shift.

A1.5 JET Collaboration

The JET machine operated during 2006 after the long shut-down for the new diagnostic systems,new divertor, and NBI upgrading. The new ICRH antenna was not ready for integration in themachine. Three campaigns (C15-C16-C17) were carried out. The organisation of the experimentalprogramme was led by two main task forces (S1 and S2). The experiments proposed by the othertask forces (Diagnostics, Heating, Magnetics, Exhaust, DT) were incorporated in the S1 and S2experimental programme.

With regard to the European Fusion Development Agreement (EFDA) JET 2006 work programme,ENEA participated in the commissioning of systems included in the JET Enhancement Programme(EP), the organisation of new enhancements for JET-EP2 (2006-2008) and the realisation ofexperiments in campaigns C15-C17. ENEA has provided EFDA JET with the EFDA associatedleader for JET, two task force leaders (Transport and Diagnostics), one deputy task force leader(Advanced Tokamak Scenario, S2), one responsible officer (RO) in the EFDA JET close support unit(CSU) (RO for H-mode Scenario (S1) and Transport task forces) and one RO for enhancements inthe EFDA JET CSU.

Participation in the JET EP/EP2

JET neutron profile monitor: fast data acquisition system for neutron/gammadiscrimination. Digital techniques for neutron detection/spectrometry are important in view of ITERapplication as they allow the realisation of systems that provide high count rates (MHz),simultaneous counting and spectroscopic measurements of both neutrons and gamma-rayemission (at present not technically feasible with conventional analog pulse shape discrimination)and the possibility of post-experiment (re)processing of data with different analysis techniques andanalysis of pile-up events.

Under an EFDA task the 14-bit 200 MS/s digitizer system for fast sampling of pulses and



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neutron/gamma digital pulse shape discrimination (DPSD)[A1.80] to be used with scintillators was installed on thecentral channel of the KN3 neutron camera at JET andcommissioning took place in November 2006. Data froma large number of plasma discharges were acquired. Theresults demonstrate the capability of the DPSD system toprovide simultaneously 2.5- and 14-MeV neutron countrates as well as pulse height spectra: note the detection ofion tails in a discharge with NBI and ICRH (fig. A1.18).Comparison of analog and digital count rates indicatesgood agreement between the two systems (fig. A1.19).

Optimisation of the system hardware and software is alsoin progress under an EFDA Underlying Technology task. Inparticular, pile-up is currently being investigated with theuse of a set of data acquired with the DPSD system onJET. The plan is to prepare a software module to deal withpile-ups, and also to perform neutron/gamma separationand pulse height analysis on such events, which willeventually be included in the existing software package.Along the same line of research, two further tasks havebeen started in collaboration with TRINITI on neutrondetector digital electronics and radiation hardness testing.

CVD diamond detectors for neutron measurement.Under the Small Enhancement agreement, two diamonddetectors produced by the chemical vapour deposition(CVD) technique were installed at JET and workedcontinuously during the C15-C17 experimentalcampaigns. One detector is polycrystalline diamond(p–CVD) covered with a thin layer (2 μm) of lithium fluoride(LiF) 95% enriched in Li-6. The latter converts low-energyneutrons into alphas and tritons of about 2 MeV and2.7 MeV respectively, which are easily detected by thediamond film and hence the total neutron emission can bemeasured. To further enhance its response the detector is embedded in polyethylene. The other detectoris a single crystal diamond (SCD) film with a special heavily doped boron contact covered with a layer ofenriched 6LiF (2 μm thick) for simultaneous detection of total neutron emission and 14-MeV neutronemission from triton burn-up. This detector was also used in a first attempt to perform neutronspectrometry. Both detectors also measured the time-dependent neutron emission during each pulse.

The goal was a) to demonstrate the capability and reliability of diamond detectors as neutron monitorsduring long–lasting experiments under ITER-like working conditions; b) to demonstrate the capability of asingle SCD detector covered with LiF to simultaneously detect and discriminate between total and 14-MeVneutrons produced by triton burn-up. The job output will be a comparison between CVD data and thoseobtained from the official JET neutron detectors (fission chambers and silicon diodes).

Figure A1.20 shows the correlation between the total neutron emission measured by the p-CVD (as wellas the SCD) and that (average value) recorded by the fission chambers (FCs) available at JET. The degree

[A1.79] S.E. Parker et al., Phys. Plasmas 6, 1709 (1999)

[A1.80] M. Riva, B. Esposito and D. Marocco, Proc. 10th Inter. Conference on Accelerator & Large Expt. Physics Control Systems - ICALEPCS(Geneva 2005), paper P-O2.041-4, http://epaper.kek.jp/ica05/proceedings/pdf/P3_041.pdf

25

10-2

10-4

10-6

0 4 8 12 16

Shot #68445 t = 46.0 s

t = 51.6 st = 50.2 s

t = 47.4 st = 48.8 s

Proton energy (MeV)

Cou

nts

(arb

. uni

ts)

Fig. A1.18 – Pulse height spectra in JET discharge

#68445: NBI and ICRH are injected at t>46 s

7×104

5×104

3×104

1×104

50 54 58 62

Shot #68569

neutron analog (10 ms)gamma analog (10 ms)neutron digital (10 ms)gamma digital (10 ms)

Time (s)

Cou

nts/

s

Fig. A1.19 – Comparison between analog and digital count

rates in the 2.5-MeV neutron energy range (JET discharge

#68569)

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of agreement between the two detectors is excellent in the whole range of interest for JET, that isfrom 5.0×1014 n/shot up to the highest neutron yields (>4×1016 n/shot) produced during C17.Figure A1.21 reports the behaviour of the p-SCD detector vs JET pulses and thus as a function oftime. Also in this case the stability is proven.

ENEA’s participation in the JET-EP2 concerns further implementation of the enhancements: fastdata acquisition for the neutron camera; new calibration, with new fast electronics for the NE213compact neutron spectrometer; a new monochrystal CVD to be tested for the neutronspectrometry; new CVD detectors to be tested for ultraviolet radiation detection.

Participation in experimental campaigns C15-C17

ENEA has presented JET with about 20% of the proposals considered for campaigns C15-C17. Theproposals are mainly dedicated to the work carried out by TFS2 (Advanced Tokamak Scenario), TFM(Magnetics), TFD (Diagnostics). The following is a short presentation of some preliminary results ofthe 2006 experiments.

Advanced Tokamak Scenario

• Optimisation of hybrid advanced regime with electron heating. The activity consisted in planningand co-leading the sessions and coordinating the diagnostics in the control room. The hybridregime with Te>Ti was established, and subsequently i) density scan, ii) current profile scan, iii)power scan were carried out. This experiment was done to complete the database with morerefined diagnostic coverage, in particular, the charge exchange and motional Stark effect (MSE).Ion temperature, rotation profiles and impurity density were carefully measured for transportanalysis. The plasma parameters of the reference pulse (#62779, in C13) were magnetic fieldBT=3.2 T, plasma current Ip=2.3 MA, neutral beam heating power PNBI=9 MW, ion cyclotron rfpower PICRH=9 MW, lower hybrid current drive power PLHCD=1 MW. The hybrid current profilewas obtained with LHCD in preheating. The main heating was performed with equal neutral beamand ICRH power, resulting in peak temperatures Te=9-11 keV, and Ti=7-8 keV at a density of3×1019 m-3. The confinement regime was H-mode with H89 ~2, and small edge localised modes(ELMs). The scenario is characterised by a sawtooth-free period and by frequent and very smallELMs, after LH preheating (fig. A1.22), where the H89 ~2, and small n=2 NTMs (neoclassicaltearing modes) are detected. The spatial q profile is typical of hybrid regimes (fig. A1.23) where alarge region of flat shear (with qmin≥1) is created at the plasma centre, when the maximum βN isreached.

• ITER-relevant ITB scenario at high βN and bootstrap fraction. The ITER non-inductive scenariohas to reach a high H-factor (H98(y,2)~1.5) and normalised beta (βN≥3), in the presence of afraction of bootstrap current Jbs, close to 50% of the total current. The scenario is characterisedby a non-monotonic q profile and the formation of an ITB located close to the point of minimumvalue of safety factor qmin. Experiments were done on JET at plasma parameters: magnetic field



y=2.042×10-12 x +9.463×102

R2=9.978×10-1

SCD

y=9.953×10-13 x +1.043×102

R2=9.978×10-1Dia

mon

ds (

coun

ts)

3.5×10162.5×10161.5×10165×1015

8×104

6×104

4×104

2×104

0

FC (counts)

CVD02SCD03

Rat

io

1.5

1.1

0.9

0.7

0.5

1.3

69100689006870068500

Pulses

y= -2.869×10-6 × +1.252R2=2.780×10-4

Fig. A1.20 – Correlation between p-CVD and SCD

detectors and FC

Fig. A1.21 – Ratio between p-CVD and FC counts vs

JET pulses


BT=2.3 T, plasma current Ip=1.5 MA, neutral beamheating power PNBI=22 MW, ion cyclotron heatingpower PICRH=6.2 MW, LHCD powerPLHCD=2.2 MW, density close to the Greenwaldlimit nG=Ip/(π a2)=0.5×10 20 m-3, Te=3-5 keV. Thesafety factor at the edge was q95~5, and thetriangularity δ~0.4. A q profile with negativemagnetic shear is formed using LHCD early in thedischarge, and high NBI and ICRH power areadded when the minimum q is just above 2, totrigger an ITB as qmin crosses 2. Two configurationswere used for this experiment: ITER_AT (AdvancedTokamak) and high beta poloidal, in two separatesessions. To maintain low ELMs, neon or D2 gaspuffing is used, and this tool helps also to make thescenario suitable for operation with a Be wall.Figure A1.24 shows the main results in terms ofnormalised beta: the normalised beta is plotted vsthe no-wall beta limit (defined as βN no-wall=4li). Thebest results βN,max~3 are obtained when bothelectron and ion ITBs occur at the same radius andstrength. The value of the fusion gain vs the densitynormalised to the Greenwald density is consistentwith that useful for ITER (fig. A1.25). This scenarioso far is limited by strong ELMs appearing at peakβN (fig. A1.26). Despite the large ELMs, the ITBpersists for several confinement times, but then it islost due to detrimental MHD activity linked to thepresence of low magnetic shear, as the q profileevolves from negative to positive magnetic shear.

27

107

103

WV

V e

V

0.8

0.20

0.10

086

4

20.4

0.2

0

0.4

0

1.5

0.5

Time (s)46 48 50 52 54 56

Fig. A1.22 – From the top. Shot #68383 First plot: heating

waveforms LHCD total power (red), ICRH (magenta), neutral

beams (blue). Second plot: βN (red) and H89 factor (blue); Third

plot: n=1 (red), n=2 (blue) MHD modes. Fourth plot:

measurements of Te in two positions. Fifth plot: Dα outer divertor

5

4

3

2

1

2.0 3.02.5 3.5

Time = 49.94 sTime = 51.95 sTime = 53.96 s

R(m)

q

#68383

Fig. A1.23 – Evolution of the q(r) profile as measured by MSE

β N

4Ii

4.0

3.0

3.5

2.5

1.5

0.5

2.0

1.0

00 0.5 1.5 2.5 3.51.0 2.0 3.0 4.0

Fig. A1.24 – Normalised beta βN vs the no-wall

beta limit defined as βN no-wall=4li

H89

β N/q

952

ne/nG

0.35

0.30

0.20

0.10

0

0.25

0.15

0.05

0 0.2 0.4 0.6 0.8 1

Fig. A1.25 – Figure of merit of fusion gain

H89βN/q295 vs normalised electron density

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• High-resolution Thomsonscattering (KE11). ENEAFrascati has been involved inthe commissioning of the high-resolution Thomson scattering(HRTS) system required for theexploitation of manyexperiments. The analysiscode of the HRTS data wasdeveloped and used duringcommissioning on the plasma. A preliminary projectof a system for laser alignment control usingcameras has been outlined. The aim is to monitorthe laser beam incident on the input window and onthe beam dump internal to the vacuum vessel.

• Motional Stark effect. The tools presently availableto determine the spatial q profile were studied: i)EFIT + MSE ; ii) EFIT+polarimetry; iii) point-to-pointanalysis. The aim of the study was to determine thesensitivity of the q profile to the data sources and tothe method, and the accuracy of the subsequentdetermination, in particular for hybrid discharges(exp S2-4.3 - Optimisation of a hybrid scenario withelectron heating) where the q(r) spatial profile in theplasma central region is critical. For thesedischarges substantial agreement has beendetected between the results of the various methods. The MSE data analysis was criticallyreviewed by comparing different constraints on the EFIT data, e.g., choice of MSE channelweights, data from polarimetry, variation in pressure constraints and polynomial degree. Wherepossible, the results were checked against proof of the existence of rational surfaces for q givenby mode analysis of fast diagnostics or the occurrence of sawteeth. As an example, figure A1.27shows the q profiles in the proximity of a 3/2 mode reconnection, with the final value of q in theregion interested by the mode close to 1.5. An alternative method for processing MSE data,previously developed at JET [A1.81], has been retrieved and tested on several discharges againstthe EFIT equilibrium. According to some hypotheses on the shape of internal flux surfaces, oncethe last closed surface is known, it is possible to process individual MSE data points, obtainingindependent determinations of the radial q points. This minimises the effect on the overall profileof the errors on individual channels (some of which are occasionally affected by spurious radiationwhich makes them completely unreliable). More work is being done to extend the comparison toseveral different experimental scenarios. The activity in support of S2 experiments wasconcentrated on hybrid heating studies and on high βN. Inter-shot analysis of the q profiles hasbeen a useful tool to achieve the desired configuration, mainly monitoring the central q value.Broadening of the q profile observed by MSE data in particular conditions of high beta dischargesis under detailed investigation.

• Polarimetry. Polarimeter data were analysed to find the consistency of measurements with varioustheoretical models developed recently. A dataset including 300 discharges (2003-2006) wascreated, where the validation of data of the interferometer and the light detection and ranging -Thomson scattering (LIDAR-TS) system was accurately checked. The dataset containedmeasurements of channel 3 of the JET polarimeter [A1.82]. A parasitic experiment (Polarimetry at



β NZ

max

(m)

κH

αM

HD

n=1

Time (s)

3.02.82.62.4

1.85

1.75

1.68

0.5

1.51.0

2.0

210

1.721.76

44.5 45.0 46.0 46.545.5

#68927Fig. A1.26 – Time evolution of βN, Zmax

plasma position, elongation κ, Hα and

MHD (n=1) monitors

Time = 47 s

#70068

Time = 46 s

R(m)

q

10

8

6

4

2

2.0 2.5 3.53.0

Fig. A1.27 – Spatial profiles of the q safety factor

Ref

eren

ces


high ne and Te) was partially executed (during theTOFOR commissioning sessions, 19-21 April 2006) todetect the effect of the (high, >6 keV) electrontemperature on model predictions (shots #66016,#66068). The main conclusions of the analysis are thatthe Cotton-Mouton phase shift can be used forevaluation of the line integral of electron density.Figure A1.28 shows the line integral of electron densityn_e obtained from the polarimeter Cotton-Mouton measurement vs the n

_e measured by the

interferometer. Substantial agreement emerges from the two independent measurements of plasmadensity. The model of Stokes equations (where the inputs are taken from LIDAR TS and EFIT equilibrium)is in good agreement with measurements even when corrections for the electron temperature areincluded in the analysis (fig. A1.29).

• Neutron emission profiles and fuel ratio measurements. ELMy-H mode plasma scenarios with tritiumpuff of the Trace Tritium Experiment have been analysed by using simultaneous DD 2.5–MeV and DT14-MeV neutron emission profile measurements. Two-dimension spatial profiles of the tritiumconcentration were obtained, which provided useful information for transport analysis and tritiumdiffusion [A1.80].

• NE213 liquid scintillator. A new neutron detection system has been built and installed at JET. It is basedon a liquid scintillator cell (NE213-BC501 A), a light emitting diode (LED) connected to stabilisationhardware for PMT high voltage gain control, and a light guide as interface/coupler with thephotomultiplier XP2020. The LED system provides calibrated and stable light pulses (at 1 kHz) used asreference for gain control purposes. The new system makes use of DPSD electronic hardware thatprovides separate neutron and gamma signals for spectra acquisition. Pulse height spectra of variousplasma scenarios were acquired during the JET restart and 2006 experimental campaigns. The presentactivity together with the project Prototype Digital Pulse Shape Discrimination Module, a newneutron/gamma DPSD, is aimed at improving neutron spectroscopy at high count-rate operation forfuture JET applications, and at assessing its potential for ITER.

A1.6 PROTO–SPHERA

The PROTO-SPHERA [A1.83] system proposed at the ENEA Frascati research centre is a simplyconnected magnetoplasma configuration composed of a spherical torus (ST, with external diameter

[A1.81] R. Giannella et al., Rev. Sci. Instrum. 75, 4247 (2004)

[A1.82] F. Orsitto et al., Proc. 33rd EPS Conference on Plasma Physics (Rome 2006), on line at: http://epsppd.epfl.ch/Roma/pdf/P1_073.pdf

[A1.83] F. Alladio et al, Nucl. Fusion 46, S613 (2006)

29

0.08

0.06

0.04

0.02

0-0.01

0 10 20 30ne,interf.

n e,C

otto

n-M

outo

n Fig. A1.28 – Line integrated plasma density (n

_e) deduced from Cotton-Mouton is

plotted vs neL measured by the interferometer

40 45 50 55 60 65 700.02

0.06

0.10

0.14

0.18

0.22

Time (s)

s3/s

2

KG4 data PHASshot#66002 ch#3numerical solutionnumerical solutionincluding Te cor-rections

Fig. A1.29 – Cotton-Mouton phase shift measured by

channel 3 of the polarimeter (blue trace) shot #66002,

together with the calculation of the signal made using the

Stokes equations (black stars) and including the effect of

the electron temperature (red crosses)

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Fusio

n P

rogra

mm

e

2Rsph=0.7 m, with closed flux surfaces and toroidalplasma current IST≤240 kA) and a hydrogen plasmaarc, taking the form of an electrode-fed screw pinch(SP, with length LPinch~2 m and midplane diameter2×ρPinch~0.08 m, with open flux surfaces and plasmaelectrode current Ie=60 kA), see figure A1.30a). Such acombined plasma configuration has been devisedtheoretically under the name "flux-core-spheromak"(FCS). The central metallic conductor of a sphericaltokamak will be replaced in PROTO-SPHERA by thescrew pinch acting as a plasma central column. The SPand the ST will have a common embedded magneticseparatrix: resistive instabilities will drive magneticreconnections, injecting magnetic helicity, poloidal fluxand plasma current from the electrode-driven SP intothe ST and converting into plasma kinetic energy afraction of the injected magnetic energy. The SP will bemagnetically given a disk-shape near each electrode(fig. A1.30b)), with singular magnetic X-points on thesymmetry axis.

The MULTI-PINCH experiment (fig. A1.31) is being builtas an initial partial setup of PROTO-SPHERA, devoted

to assessing and clarifying the most critical points of the PROTO-SPHERA experiment from the SPpoint of view: to explore the breakdown conditions and the pinch stability in the starting phase ofthe PROTO-SPHERA discharge, in the presence of the poloidal field (PF) shaping coils alone andtherefore in the absence of the spherical torus.

As a sign of international support for this project, a collaboration in the field of spherical tokamakshas been established with the UKAEA-Culham Association. ENEA Frascati has been contributingwith personnel to the MAST experiment in Culham since 2004. In 2004 UKAEA Culham donated toFrascati the available START equipment (in particular the vacuum vessel), and further contributionsfrom UKAEA-Culham can be expected during the final construction phases, commissioning andoperation of MULTI-PINCH, with respect to diagnostics and manpower.



a)

Anode

Cathode

Spherical torus

Divertor PF coils

Screw pinch

R=REL REL=0.4 m

SP

ST

I e

IST

b)Water-cooled anode ring

Directly heated cathode ring

Gas flux

Gas exhaust

ST

SP

SP

Fig. A1.30 – a) Sketch of the PROTO-SPHERA system; b) Cut-out sketch of plasma and electrodes

2.5

m

2 m

Fig. A1.31 – MULTI-PINCH


MULTI-PINCH will produce a stable screw pinch with current Ie≤8.5 kA, namely, the current expected inPROTO-SPHERA before the ST formation. The four pairs of PF shaping coils will be fully recovered forPROTO-SPHERA. In 2005 the constructive design of the PF shaping coils was completed with ASGSuperconductors (Genoa, Italy) and their construction will be completed by the beginning of 2007(fig. A1.32).

A European call for tender for the construction of the remaining parts of the MULTI-PINCH load assemblywill be sent out in spring 2007. Examples of the detailed drawings for the MULTI-PINCH load assembly aregiven in figures A1.33-A1.34.

The power supplies have been defined and their procurement should be such as to have the machineready for operation in 2009.

If the MULTI-PINCH experiment gives positive results, the PROTO-SPHERA setup can be completed byadding the ST compression coils, along with an improved power supply, capable of raising the pinchelectrode current from Ie≤8.5 kA to Ie=60 kA in ∼1 ms.

31

Fig. A1.33 – Isometric view of the MULTI-PINCH anode Fig. A1.34 – Isometric view of the MULTI-PINCH cathode

Fig. A1.32 – The four pairs of MULTI-

PINCH PF coils and an enlargement

of a few details

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A2 Preliminary Design of FT3


Fusion is the most promising energy source as it can satisfy the energy needs in a safe and environmentally

responsible way. For fusion to play a major role by the second half of the 21st century, rapid exploitation of

ITER and an adequate parallel programme of material development (IFMIF) are mandatory, as proposed in

the so–called “fast track” approach to fusion energy. Within this approach, the construction of a

demonstration/ prototype reactor (DEMO) could start after ten years of ITER operation. Such an ambitious

time schedule specifically requires rapid progress in the exploitation of ITER during the first ten years of

operation, so that the DEMO regimes of operation can be demonstrated by the start of DEMO construction.

This requires parallel R&D activities on devices that are able to simulate burning plasma conditions but are

more flexible than a nuclear device such as ITER.

The European Power Plant Conceptual Study shows that the DEMO regimes must go beyond the regimes

developed for ITER. Although the extrapolation in plasma parameters (with respect to ITER) is limited, their

demonstration will require a significant exploratory effort. Indeed, DEMO will operate with a fraction of self-

generated (bootstrap) current close to 70%, use sophisticated methods for plasma control and require

techniques to reduce the heat flux on the plasma–facing components. All these requirements push the

plasma close to the operational limits where the risk of plasma disruptions is high. Furthermore, different

technological solutions for plasma–facing components and control methods have to undergo testing, which

would clearly be difficult and expensive to perform directly on a nuclear device such as ITER. Thus, the

successful development of the DEMO scenarios, prior to testing them on ITER, requires a preparatory

activity on smaller (than ITER) devices with sufficient flexibility and capable of simulating burning plasma

conditions.

Although many of the existing devices can provide important contributions to the preparation of ITER

operation, the requirement that the plasma behaviour be sufficiently close to that of ITER sets stringent

constraints on the plasma conditions that must be achieved in order to investigate ITER-relevant scenarios

in a meaningful way. The aim of the present proposal is to show how the preparation of ITER scenarios can

be effectively implemented on a new facility that will: i) work with deuterium plasmas, hence avoiding the

problems associated with the use of tritium, and will simulate alpha–particle dynamics by using fast ions

accelerated by heating and current drive systems; ii) work in a dimensionless parameter range close to that

of ITER; iii) be capable of long pulse operation at high plasma performance; iv) test technical solutions (e.g.,

the use of full tungsten) for the first wall/divertor that are directly relevant to ITER and DEMO.

Such a facility (FT3) could be ready in advance of the ITER operation phase and would require, taking into

account the infrastructures available in Italy, limited investment and operation costs. FT3 would be

designed, constructed and operated in the framework of a collaboration with other associations. In

particular, FT3 would make use of the competence available at ENEA, the National Research Council (CNR)

Milan and at the Reversed Field Pinch Experiment (RFX) consortium and would be the focus of Italian

activities in fusion after completion of the FTU and RFX scientific programmes.

32


A2.2 Scientific Motivation of the Proposal

Rationale for the choice of FT3 parameters. The conditions to be satisfied in order to reproduceITER–relevant plasmas can be summarised as follows:

• ITER–relevant geometry (same shape of magnetic surfaces and divertor configuration);

• a ratio between energy confinement time and electron-ion equipartition time similar to that of ITER;

• production and confinement of energetic ions in the half-MeV range;

• a large ratio between heating power and device dimensions to simulate the large heat loads on thedivertor plasmas;

• pulse duration (normalised to the plasma current diffusion time) similar to that of ITER to study plasmascenarios in steady–state conditions.

It is possible to show that these conditions imply the following set of parameters:

• plasma current I above 4.6 MA;

• auxiliary heating systems able to accelerate the plasma ions to energies in the range of 400 keV;

• device dimension of 1.8 m;

• pulse duration up to 100 s.

To accelerate plasma ions up to 400 keV, it is impossible to use neutral beams produced by acceleratingpositive ions, which is the most diffuse heating scheme, as neutralisation efficiency rapidly drops above140 keV. Other methods such as ion acceleration by ICRH or neutral beams produced by acceleratingnegative ions have to be employed.

The FT3 parameters are shown in table A2.I and compared with those of JET, JT60 SA (the proposed upgradeof the JT60-U device, under the Broader Approach Agreement) and ITER. Comparison of FT3 with JET andJT60-SA shows that the dominant heating scheme in FT3 is ICRH, whereas in JET and JT60-SA, positiveneutral beam injector is mostly employed; thus only in FT3 can fast ions in the correct energy range beproduced; also the pulse duration is much longer in FT3 than in JET.

The initial configuration will be equipped with ICRH (20 MW), ECRH (4 MW) and LHCD (6 MW) power.Although such a configuration is adequate to investigate the physics issues relevant to the FT3 mission,the machine is designed so that, if necessary, further upgrades in auxiliary power (in particular a neutralbeam injector) could be accomodated.

Plasma parameters and equilibrium configurations. The ITER design currently foresees theinvestigation of three main equilibrium configurations: a) a standard H-mode at I=15 MA with a broadpressure profile (po/<p>=2); b) a hybrid mode at I=11 MA with a narrower pressure profile (po/<p>=3); c) asteady-state scenario at I=9 MA with a peaked pressure profile (po/<p>=4). The FT3 equilibriumconfigurations have been designed so as to reproduce the ITER equilibrium configurations with the plasmacurrent being scaled by a factor of 3. The correspondingplasma parameters are shown in table A2.II which reportsthe parameters achievable with an auxiliary power of20–30 MW for each scenario.

All the plasma equilibria satisfy the following constraints:a) a minimum distance of 3 λE between plasma and firstwall to avoid interaction between plasma and mainchamber (here, λE is the energy e-folding length,assumed to be 1 cm on the equatorial plane); b) currentdensity in the poloidal field coils not exceeding 30 MA/m2.Within these constraints enough flexibility is maintained toallow different plasma shapes, efficient pumping andstrike point sweeping. The location of the poloidal field

FT3 JET JT60-SA ITER

R(m)/a(m) 1.8/0.6 3.0/1.0 3.0/1.0 6.2/2.1

B(T) 6.7 3.9 2.7 5.3

I(MA) 5.0 3.9 5.0 15

PICRH(MW) 20 12 0 20

PNNBI(MW) 0 0 10 40

PPNBI(MW) 0 25 24 0

PECRH(MW) 4 0 7 20

PLH(MW) 6 3 0 20(*)

tflat-top(s) ∞ 10 ∞ ∞

Table A2.I – FT3, JET, JT60-SA and ITER parameters

(*) to be decided

33

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coils has been optimised to minimise the magnetic energy, produce enough magnetic flux (up to25 Wb) for the formation and sustainment of each scenario and produce a fairly good field null atplasma breakdown (Bp/BT<3×10-4). The H-mode magnetic equilibrium is shown in figure A2.1.

For each equilibrium configuration, a self-consistent set of plasma parameters was determined(table A2.II). A coupled core-edge model that employs a 0-D description of the plasma core and atwo-point model for the scrape-off and divertor plasma were used. The ITER98y2 scaling for energyconfinement time was assumed with an enhancement factor of H98 for the three scenarios. Theedge plasma density was chosen as equal to one third of the average density. Access toH–mode conditions was checked in all the cases on the basis of the most recent ITER scaling laws.The range of variation in the threshold power for H–mode access is also shown in table A2.II. Theamount of radiated power was evaluated on the basis of the intrinsic (tungsten) and externallyinjected (neon) impurities. The fraction of radiated power in the plasma core is in the range 30%.The resulting power load on the divertor plates remains below 20 MW/m2.

Plasma position and shape control have also been studied for the reference scenario. Optimisationof the copper shell position slows the vertical stability growth time down to 100 ms with acomfortable stability margin (ms(EFDA)=1.1, ms(CREATE)=0.54). No 3D effects associated with theshell and vessel structure have been considered so far. The response of the system to a 1–cmvertical displacement event, a minor disruption and a step of 100 kA in the plasma current weresimulated by monitoring the plasma-wall distance (gap) at six different poloidal locations. Theresulting maximum change in the gap is less than 3 cm with a settling time less than 2 s.

Physics of FT3 plasmas. The plasma parameters obtained above were fully validated in order todetermine the amount of absorbed power from the auxiliary heating systems, the fast particlepopulation generated by the auxiliary heating systems and the amount of plasma current drivennon-inductively. In FT3, three auxiliary heating methods are foreseen:

• The fast ion population is mainly produced by acceleration of a minority species by ICRH. Sincethe magnetic field of FT3 is assumed to be constant in all the scenarios (B=6.7 T), He3 can beused as minority species in the frequency range 60–80 MHz. The amount of power foreseen is20 MW at the plasma.

• The MHD activity is controlled by ECRH and ECCD at 170 GHz. At 6.7 T resonance occurs inthe region beyond the magnetic axis. The amount of power foreseen is 4 MW.

• The plasma current for the steady-state scenario is generated by LHCD at 3.7 GHz. The amountof power foreseen is 6 MW.

In a second phase a fourth auxiliary system, namely a negative ion system, could be added to inject



H-mode H-mode Hybrid Steady state

I(MA)/q95 5/3 5/3 3.6/4 2.8/4.9

H98 1.0 1.0 1.3 1.5

n20 3.7 2.6 1.95 1.35

n/nGW 85% 60% 60% 60%

P(MW)/Pth(MW) 30/13-23 20/11-17 20/9-13 30/8-10

βN 1.85 1.42 1.8 2.1

tflat-top(s) 6 6 30 100

τE(s) 0.42 0.48 0.47 0.25

To(keV) 7.9 8.6 8 13

Tplate(eV) 22 26 67 76

frad 32% 27% 30% 53%

Table A2.II – FT3 plasma parameters. The magnetic field is6.7 T in all the cases

z(m

)

r(m)

1.5

0.5

-0.5

-1.5

-1

0

1

1 2 31.5 2.5

Fig. A2.1 – H-mode equilibrium configuration

35 Progress Report 2006

an energetic ion population in the direction parallel to the equilibrium magnetic field, complementing in thisway the physics that can be studied with ICRH–produced fast ions with velocity mostly perpendicular tothe equilibrium magnetic field.

Ion cyclotron absorption was estimated using the FELICE and TORIC codes. Both codes solve the integro-differential equation for wave propagation and absorption: FELICE solves the equation in slab geometrywirh the use of the self-consistent electric field radiated by the antenna; TORIC solves the equation intoroidal geometry by employing a spectral method. Three absorption regimes can possibly play a role:minority absorption (which is the absorption channel to be maximised), electron Landau damping andmode conversion to the ion Bernstein wave. The analysis by the FELICE code tends to give a lowerminority absorption than those from TORIC. A minority concentration of 2% yields a minority absorption of50% (FELICE) or 70% (TORIC) with a two–strap antenna with relative phase 180°, the remaining powerbeing directly absorbed by the electrons. The power deposition profiles are shown in figure A2.2a) for thevarious absorption mechanisms. The parameters of the ion tails produced at a power level of 24 MW arein agreement with the Stix theory, with the local absorbed power density obtained by the deposition code.For the case shown in the figure, the effective temperature of the ion tail predicted by the Stix theory is 188keV for a power density of 45 MW/m3. The minority ion distributionfunction is shown in figure A2.2b). The fast–particle concentration is0.3%. Note that a slowing down distribution function with a maximumenergy of 400 keV has an average energy between 189 keV and149 keV for a critical energy between Ec=150 keV and Ec=50 keV.Therefore, the fast–particle population is in the correct range ofparameters to simulate the ITER fast–particle dynamics.

The MARS code was used to perform a preliminary analysis of theglobal MHD stability for the steady–state scenarios in order toinvestigate the possibility of stabilising resistive wall modes. The no-wall beta limit corresponds to βNc=2.8, whereas an ideal wall atr/a=1.3 has a beta limit corresponding to βNc=3.24. Feedbackcontrol analysis shows that the use of internal poloidal field sensorscan allow full stabilisation of the mode, using both internal andexternal feedback coils, whereas radial field sensors do not allowstabilisation.

The ECRH system on FT3 is mainly dedicated to stabilisation ofneoclassical tearing modes in hybrid and steady–state scenarios, at densities below 3.6×1020 m-3, whichis the cut-off for the ordinary mode for the chosen frequency of 170 GHz (the same as ITER).

As an example, figure A2.3 shows the m/n=2/1 island with (W) evolution for a 2.8 MA scenario andβN=2.1. The wave is launched from an upper port at an angle of 10°. Wave propagation is evaluated withthe electron cyclotron wave Gaussian beam (EC GB) ray-tracing code. The m/n=2/1 island evolution asdetermined by the modified Rutherford equation is also shown in figure A2.3. The island width (6 cm) ismaintained below the ECRH deposition width for an injected power of 3 MW and corresponds to about50% of the value at saturation without ECRH applied.

Lower hybrid current drive can be used on FT3 to control the current density profile in advanced scenarios.

W/c

m3

60

40

20

00 0.2 0.4 0.6 0.8 1

r/a

Hf power absorption by species

Total ICRH power densityPower to ionPower to electrons

a) b)

log(

F)

0 100 200 300 400E(keV)

Minority ion distribution function 0

-1

-2

-3

-4

-5

Maxwellian

Fig. A2.2 – ICRH power deposition

profile for various absorption

mechanisms a) and minority-ion

distribution function b). The dominant

mechanism is minority absorption (red

curve) which produces localised

heating in the plasma centre, similar to

alpha-particle heating in ITER. The fast

ion energy is in the range of 400 keV

W(m

)

t(s)

0.12

0.10

0.08

0.06

0.04

0.02

00 1 20.5 0.5

EC on

Bt =6.7 Tβp=0.6(βcr=0.05)

βN=2.1 T0=13 keV n0=21×1019m-3

PEC = 3 MWWsat

rs/a=0.68ω=1.3 kHzj_peakEC/jbs ~ 1.08Δp' =-2

w/δj = 1

q = 2

Steady state

Fig. A2.3 – Evolution of the 2/1 island without

(green) and with (red) EC power applied

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A study of LH penetration and absorption wasperformed in a parameter range typical of FT3 scenarios.Figure A2.4 shows the ray trajectories for a plasmaequilibrium representative of FT3 scenarios with anaverage density 1020 m-3 and a central temperature of13 keV. The wave frequency is 3.7 GHz and threevalues of the parallel refractive index are considered. Inall the cases the wave is absorbed around mid–radius asrequested for this kind of scenario. Current driveefficiencies in the range 0.3×1020 Am2/W are predicted.

A2.3 Preliminary Design Description

Load assembly. The FT3 load assembly (fig. A2.5) consists of the vacuum vessel and its internalcomponents (first wall, divertor, passive stabiliser structure), the magnet system and the poloidalfield coils. Since the maximum flat-top duration is 100 s, an actively cooled oxygen–free copper coilsystem has been chosen for the magnet. The cooling is guaranteed by pressurised sub-cooled(ΔTsat=26 nitrogen [LN2]) flowing through suitable channels carved in the coil turns. Each turn is fed

by LN2 independently (the LN2 flows in parallel in each turn) to limitthe pressure drop to an allowable value and therefore avoid

LN2 vaporisation. The Ohmic power dissipated in themagnet is about 50 MW, which implies a LN2 mass

flow of about 1600 kg/s. The magnet consists of 18coils, each made up of 14 copper plates suitablyworked in order to have 6 turns in the radialdirection. Ripple correction is made by ferriticinserts. The 14 plates are welded corresponding tothe most external region in order to obtain a

continuous helix. The maximum turn thickness is30 mm. The plates are tapered at the innermost region

to get the needed wedged shape; the minimum turnthickness is about 15 mm. The magnet insulation is made of

glass-fabric epoxy, both for ground and inter-turn.

The coils are fixed together by the surrounding steel structure. Two pre-compressed rings situatedin the upper-lower zone keep the whole toroidal magnet structure in a wedged configuration. Thestructure is also used to position the poloidal coils, which surround the toroidal magnet, and to fixthe vacuum vessel supports. Cooling of the toroidal–magnet structure is obtained by the contactwith the actively cooled components. To enable operation at 80 K, the whole machine is kept undervacuum by a metallic cryostat.

The magnet dimensions were determined by the cooling requirements. It was necessary to limit thecurrent density to 30 MA/m2. It turns out that from the structural standpoint the magnet section isadequate to sustain the forces. The first rough evaluation of the stresses indicates the maximum VonMises to be below 200 MPa. The fabrication process is based on well–assessed technology utilisedfor FTU and other prototypical components, so no further R&D is required for the construction ofthe toroidal magnet.

The FT3 free-standing central solenoid (CS) is segmented in six coils to allow plasma–shapingflexibility, to facilitate manufacture and to allow cooling. The poloidal field coils and busbars are madeof hollow copper conductors. They have to withstand both vertical and radial electromagnetic loads,



Fig. A2.5 – FT3 Load assembly

Z(m

)

R(m)

1.2

0.8

0.4

-0.4

-0.8

-1.20

0

1.200.80.4-0.4-0.8-1.20 0

Fig. A2.4 – Lower hybrid wave trajectories for three values of the

parallel refractive index


and are free to expand radially. The power to be removed from the poloidal field coils, keeping the coils atcryogenic temperature, is about 12 MW. The CS coils are layer wound and have an even number of layersfor the electrical leads to be located on the same side of the coil. The conductors are wrapped with glassfabric and kapton tapes and vacuum impregnated with epoxy resin. Radial grooved plates at the interfacesbetween coil segments maintain concentricity. To limit the pressure drop, thus avoiding LN2 evaporation,cooling is achieved by feeding each layer independently. Due to the large dimensions of the most externalpoloidal coils, a pancake configuration is adopted in order to allow cooling of the single turn. As for thetoroidal magnet, the poloidal–coil section and conductor size were determined by the coolingrequirements.

The total FT3 LN2 daily consumption, determined on the basis of four 100–s pulses a day or 16×10 spulses, for the toroidal magnet and the poloidal coils is 150 t. A further consumption of 15 t for the lossesthrough the ports and other feedthroughs as well as to keep the vacuum vessel at room temperature mustbe considered.

The vacuum vessel is segmented by 20–degree modules. To minimise the vacuum vessel time constant,the shell is made of Inconel and the port in stainless steel. The maximum thickness of the shell is 30 mm,while the ports are 20 mm thick. The shell is manufactured by hot forming and welding. Following theprevious experience with FTU, the vacuum vessel will be supported by the toroidal field magnet system bymeans of vertical brackets attached to the TF coil case through the vessel equatorial port. According tothis constraint scheme, thermal expansion/contraction of the vessel is allowed, while nonsymmetricdisplacements that might appear during disruptions or plasma vertical displacement events are restrained.Twelve vacuum vessel sectors are equipped with five access ports. The maximum force during plasmadisruption is about 300 t for a 5–MA operating scenario. The thickness of the wall is adequate to sustainsuch a load. The vessel time constant is about 30 ms. The operating temperature of the vessel rangesfrom room temperature to 100°C. A suitable water loop is dedicated to maintaining the vesseltemperatures.

The first wall and the divertor are actively cooled by pressurised water with velocity respectively 5 and10 m/s. These components have been designed to exhaust up to a maximum heat power of 50 MWduring long pulse operation. The first wall surrounds most of the vessel wall. It consists of a bundle of tubesarmoured with 3–mm plasma–spray tungsten. The heat load impinging on the first wall is, on average,1 MW/m2 with a peak of about 3 MW/m2. The solution adopted is well suited to resisting these loads,having been tested up to 7 MW/m2. The first wall is also able to work as a limiter during plasma startup.Its temperature will be maintained around 100°C to avoid impurity adsorption. The design has to beremote-handling compatible. Maintenance will be carried out from equatorial and upper ports. The divertorhas to withstand a heat flux in excess of 20 MW/m2. The only suitable technology in this case ismonoblock, which has been tested extensively in the relevant heat flux range. The armour consists ofhollow tungsten tiles inserted in a copper tube heat sink. The heat flux component will be supported by asteel frame which acts also as a cooling circuit. To enhance the critical heat flux, swirl tapes are providedin the most loaded zone. The configuration has to allow easy maintenance operation as the possibility ofhaving to substitute some components is likely. The scheme is similar to that of ITER, with the frame actingas a carousel all around the machine. Maintenance will be carried out from the lower port.

A remote handling system, similar to the JET FARM, has been conceived for unplanned (emergency)operations. Standard maintenance tasks will instead be accomplished by a plug-in design of thediagnostics and the antennae and casked solutions. The ITER divertor maintenance procedure will be usedwherever possible. The procedure is based on the development of an ad hoc cassette–mover tractorcapable of grasping and moving the divertor cassette. Some of the maintenance tasks of the first wall aresimilar to those foreseen for the divertor, so pipe sizes could be standardised to be able to share cut andweld devices. For the first wall assembly and disassembly a classical articulated boom plus a front endmanipulator have been considered.

Power supply. The FT3 power supply system includes three main subsystems: the 400–kV mainswitchyards, the poloidal field coil (PFC) power supplies and the toroidal field coil power (TFC) supplies.Figure A2.6 shows the total power for a 5–MA scenario with a total heating power of 30 MW

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(corresponding to about 80 MW requested at thegrid) and a stationary load of 25 MW. Due to theamount of requested power, connecting to apowerful node of the 400–kV Grid would bedesirable. Nevertheless, an accurate check by theNational Grid Regulator (GRTN), including bothactive and reactive power effects on the specificgrid, might show that a 220–kV line could beadequate. Lacking such an evaluation, the400–kV line is taken as the reference solution.Within the assumed 400–kV reference solution,FT3 needs a dedicated switchyard to supply thePFC, TFC, additional heating systems and

auxiliaries. All the loads are fed by one main step–down transformer (400/36 kV) with threesecondary windings: two (225 MVA each) star connected and grounded through a resistor, to supplyFT3, and one (80 MVA) delta connected to allow free circulation of third harmonic currents. On therequest of the GRTN, active power shedding resistors could be connected to the tertiary winding.Sharing the total power between two secondary windings has the aim of making it possible to usethe 36–kV level on the secondary sides (instead of the more expensive 75–kV level), limiting the ratedcurrent within the present breaker capability at this voltage. Each circuit for the supply of the TFC andthe various PFCs is generally made up of a converter transformer, a thyristor converter unit, a protectivecrow-bar and high-speed, solid–state switches for the additional resistance units. No specific study forthe breakdown phase has been made so far.

Heating systems. The FT3 auxiliary heatingsystems are consistent with the present stateof the art and do not require additional R&Dactivity. FT3 is equipped with three systems:ICRH, ECRH and LHCD. A description of theICRH system is given in table A2.III. At amagnetic field of 6.7 T, the use of 3He minorityrequires a frequency of 68 MHz. In its initialconfiguration the system will couple 20 MW tothe plasma. A possible design of the ICRHantennae could be based on an array of six(two toroidal by three poloidal) current strapsprotected by a Faraday shield made of a set of16 non–tilted elements, with a smoothedrectangular cross section. The Faraday shield

has to suppress the components of the emitted radiation parallel to the local B-field, and shield theelectrically active components from direct contact with the plasma. All the antenna components(straps and Faraday shield rods) are water-cooled. Each antenna is fed by three high–powertetrodes “TH 526”, with a maximum rf power output of 2 MW in the frequency range 35-80 MHz.Three of the generators are supplied by a 33–kV/380 A solid–state unit. The antenna, together withthe respective vacuum transmission lines and vacuum windows, is integrated in a plug inserted inan equatorial port and removable as a single unit.

The performance of the antenna was studied with the TOPICA code on the reference FT3 H–modeplasma scenario at 68 MHz with 2% 3He minority. Electric current and magnetic current/electric fielddistribution were obtained in vacuum and with the plasma. The analysis in vacuum of the optimisedantenna showed very good (low) inter-strap coupling. The analysis with plasma demonstrated thegood performance of the antenna array in terms of power coupled to the plasma: for the standardconfiguration and for a maximum voltage of 30 kV, a power of 5 MW can be coupled to the plasmaby each array. The launched power spectrum has a maximum for n||=±6. Figure A2.7 shows thecurrent distribution on the straps, demonstrating the good efficiency obtained with this geometry:



P(M

W)

Q(M

WA

r) S

(MV

A)

Time (s)

P: active powerQ: reactive powerS: total power

-100

100

200

300

400

500

0-21 -15 -9 -3 0 6 12 18 24 30 36 42

Fig. A2.6 – Active, reactive and total power for the reference FT3 pulse

Operating frequency range ( MHz) 60±90Peak power (MW) 20Bandwidth (MHz) ±2MHz (-1db)Pulse width (s) ≥ 100Time interval between two

100–s pulses (s) 1800Type of antenna 3 rows of 2 strapsPower per strap (MW) 1 (at generator)Power coupled per antenna (MW) 5Max radiated power density (MW/ m2) 10N. of antennae 4Power per generator (MW) 2N. of rf generators 12

Table A2.III – ICRH system parameters


the current on the straps has a very high absolute value and is almostconstant along the entire length of the straps.

Four identical units compose the ECRH system, each with a gyrotron, atransmission line and a launcher. The four launchers are located in the sameport. Each gyrotron is fed by an independent power supply, capable ofhigh–frequency modulation (up to 10 kHz) and designed to be used as the actuatorin the feedback loop for mode suppression. The power is delivered from the source tothe launcher by means of an evacuated corrugated waveguide. The reference design for the launcher isbased on front steerable mirrors, with real–time control of toroidal and poloidal injection angles. No barrierwindow is considered in the transmission line. The whole system is designed to operate in feedback modewith real-time control of the main parameters (polarization, beam current, mirror steering, power, faultmanagement), addressing in this way technological issues relevant for a system working in athermonuclear plant. The considered gyrotron is a 170–GHz/1–MW source, with depressed collector anda pulse length larger than 100 s, based on the results of the R&D activity for ITER. Each gyrotron is fed bya 55–kV/50–A high–voltage power supply. The transmission line is an evacuated aluminium corrugatedwaveguide (i.d. 63.5 mm) matched to the gyrotron output beam with an elliptical mirror. Since the powerdissipated on the waveguide is small and the pulse length does not exceed 100 s, no direct cooling of thewaveguide is considered, while all the other components (mitre-bends, polarizer, dc-break) must becooled. The launcher under study, based on the front steering concept for major flexibility in terms of beamshaping and injection angles, is located in the upper vertical port. In this way, the intersection of the ECresonance with the q=2 surface, for the relative neoclassical teaning model (NTM) stabilisation, is reachedwith limited diffraction effects. The front mirror is real–time controlled at a speed compatible with all theissues assigned to the ECRH system (NTM stabilisation, sawtooth control, disruption mitigation). The beamspot radius (waist) in the plasma resonant region can be less than 3 cm, below the expected width of theNTM m/n=2/1 island at saturation. The overall losses of the design of ECRH system (waveguide, mitre-bends, microwave components and launcher) are below 8%, which can be reduced further with a HE11 toGaussian beam converter at the beginning and at the end of the waveguide.

The LHCD system is designed to routinely couple a rf power of 6 MW toFT3 plasmas. The preliminary design is based on a frequency of 3.7 GHz inpulsed regime, with pulse length up to 100 s. At this working frequencyhigh–power CW sources are available, i.e., the TH 2103 klystron, rated at500 kW/CW and 650 kW/10 s; these klystrons (table A2.IV) are thesources of the Tore–Supra and JET LHCD systems. The FT3 LHCD systemwill be equipped with two passive–active multijunction (PAM) launchers,which will simultaneously allow coupling LH waves in the plasma with severeedge conditions and effectively water cool the antenna in long operationsand with heavy thermal loads. The dimensioning of the launcher, given thefrequency, is based on the requirement of launching a peak n|| N||peak=1.9and by the cross section of the FT3 ports at the narrower point. Theresulting power density in the active waveguides is limited to PS=33 MW/m2, which is comparable withthe values normally achieved in JET and Tore Supra.

Taking into account ~20% rf losses in the transmission lines and in the launcher, a minimum rf power atthe generator of PInst=7.5 MW has to be installed, i.e., 15 klystrons to be used.

Diagnostics. A specific activity has been dedicated to studying the capability of performing detailedmeasurements of the FT3 plasma parameters. The basic diagnostics include the magnetic diagnostic(diamagnetic loops, saddle coils, Hall sensors and pick–up coils), the CO2 interferometer for measuring theelectron density profile, the ECE (Michelson, polychromator and radiometer) and Thomson scatteringsystems for measuring the electron temperature, the bolometric measurements for plasma radiation,various spectroscopic measurements (visible, UV and x rays) of the impurity content, the neutron cameraand neutron spectrometer for 2.45 neutron emission, the activation measurement and the gamma-rayscintillator. These diagnostics will be taken from FTU with minor adaptations. Further diagnostics could beprovided as a contribution in kind from other associations. Discussions are under way to assess thispossibility.

-11.540-14.704-17.869-21.033-24.198-27.362-30.527-33.691-36.856-40.020

ıJı (dB,interp)Fig. A2.7 – Distribution of current on the straps

Frequency 3.7 GHzBandwidth @ - 1 dB 10 MHzOutput power (CW) 500 kWGain 47 dBCathode voltage 60 kVBeam current 20 AEfficiency 42%Modulating anode voltage 45 kVModulating anode current 50 mA

Table A2.IV – TH 2103 mainparameters

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A3.2 Divertor, First Wall, Vacuum Vessel and Shield

Manufacturing of small-scale W monoblock mockups

Manufacturing of the prototypical component by means of the two ENEA patented technologies(pre-brazed casting [PBC] and hot radial pressing [HRP]) was successfully concluded (UnderlyingTechnology and European Fusion Development Agreement contract [EFDA] 03/1054) [A3.1-A3.5].Thermograph non-destructive (ultrasonic, lock-in thermography) testing performed with the SATIR(Commissariat à l’Energie Atomique ([CEA]) equipment showed there was no evidence of defectivezones. After the testing the mockup was sent to the FE200 e-beam facility at Le Creusot France forthermal fatigue tests (fig. A3.1).

The testing plan started with a screening at 5 MW/m2 of absorbed power. The mockup wassuccessfully tested at ITER-relevant heat fluxes: 10 MW/m2 for 3000 cycles (all), 20 MW/m2 for2000 cycles on the carbon fibre composite (CFC) part, 15 MW/m2 for 2000 cycles on the tungsten.

A3 Technology Programme


The technology activities carried out by the Euratom-ENEA Association in the framework of the European

Fusion Development Agreement (EFDA) concern the continuation of the ITER, DEMO and IFMIF R&D

programmes. ENEA has also started design and preliminary R&D activities under the Broader Approach

agreement between the EU and Japan.

In 2006 the most important results of the technology programme were achieved in the fields of plasma-

facing-component development and testing, neutron data, remote handling. However, it should be noted

that all the activities contributed substantially to the progress of the fusion programme as a whole (safety,

the Power Plant Conceptual Study, engineering activities).

The divertor CFC/W monoblock mockup fabricated using ENEA’s patented processes was tested under

fatigue heat loads and achieved results that surpassed those of the other technologies. The next step is to

industrialise the technology for application in the construction of the ITER divertor heat flux components.

Significant work was done to define quality assurance for neutronics analyses. Mockups of the ITER pre-

compression ring made in glass fibre epoxy were fabricated.

ENEA is also equipped to contribute to the ITER construction, not only through the continuing R&D

activities, but also through participation in the development of the ITER neutron radial camera and laser in-

vessel viewing system and, as an associate of the Consortium of Associations, in the construction of the

first nuclear fusion components - the Test Blanket Modules.

The activities and results documented in the following illustrate ENEA’s readiness to enter the new era

opened with the decision to build ITER.

40


Figure A3.2 shows the infrared images taken duringthe high heat flux testing and during the 3176th

cycle performed at 20 MW/m2 of absorbed poweron the CFC tiles and 15 MW/m2 on the tungsten.The images highlight the absence of surfaceoverheating. The mockup was also subjected tocritical heat flux (CHF) (fig. A3.3) to verify itsbehaviour under ITER-relevant thermal-hydraulicconditions. A CHF of 35 MW/m2 was obtained andit can be said that this value is well above thatestimated and gives a margin of 1.75 with regardsto ITER nominal loading. For the first time it waspossible to measure the CHF of a monoblockcomponent with armour tiles still joined on the tube.Figure A3.4 shows the mockup after the CHFtesting, while still connected to the FE200 facility.

The complete manufacturing and successful testingof this vertical target medium-scale mockup(fig. A3.5) can be considered a success for both thePBC and the HRP processes. A survey of themanufacturing technologies for the ITER divertorhas shown that they are valid alternatives to thecurrent techniques.

[A3.1] M. Merola et al., Fusion Eng. Des. 56-57, 173 (2001)

[A3.2] M. Rödig et al., Fusion Eng. Des. 56-57, 417 (2001)

[A3.3] M. Rödig et al., Investigation of tungsten alloys as plasma facing materials for the ITER divertor, presented at the 6th Int. Symposium onFusion Technology - ISFNT-6 (San Diego 2002)

[A3.4] E. Visca et al., Fusion Eng. Des. 56-57, 343 (2001)

[A3.5] M. Rödig et al., Post irradiation testing of samples from the irradiation experiments PARIDE 3 and PARIDE 4, presented at the 11th Inter.Conference on Fusion Reactor Materials - ICFRM-11 (Kyoto 2003) R

efer

ence

s

41

Fig. A3.1 – Monoblock mockup installed in the FE200

facility before high heat flux testing

10/19/06 INFRAMETRICS 17:59:19

2353

1997

2195 2098 1981

Fig. A3.2 – a) CFC part, b) W part

Fig. A3.4 – CFC surface after CHF testing

Fig. A3.3 – Infrared image during CHF testing at 34.2 MW/m2

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Engineering Design Activities: Vand VI test campaigns

The objective of the test campaigns in theframework of Engineering Design Activities(EDA) is to characterise the primary first-wall(PFW) panels in terms of their behaviourunder thermal fatigue in ITER-relevantconditions (temperature and thermal flux).Thermal fatigue tests on the PFW mockupsunder ITER-relevant operative conditionswere carried out to qualify the Be-metallicheat sink (Cu alloys)-austenitic 316L steelpanel joints made by hot isostatic pressing.In 2006 the EDA V campaign wassuccessfully concluded, with neither meltingnor erosion/failure of the Be tiles. Under thenew EDA VI campaign, started in lateautumn, the plan is to accomplish 30000thermal cycles. As in the previouscampaigns, the two mockups (one shown infig. A3.6) delivered to ENEA by EFDA, arebeing tested under thermal fatigue cyclingwith an emitted thermal flux up to amaximum of 0.65 MW/m2 and a cycleperiod of 300 s. The EDA-BETAexperimental setup (fig. A3.7), consisting ofa glove box operated under vacuum andsuitably instrumented (with a high specificpower CFC resistor), is connected to theCEF 2 water loop at ENEA Brasimone for themockup cooling. The main features of thewhole experimental apparatus (EDA-BETA +CEF 2) are summarised in table A3.I. Theexperimental activity should be concluded inlate summer 2007.

Hydraulic characterisation offull–scale divertor components

The main aim of the activity, started in 2006,is to perform an exhaustive thermalhydraulic experimental campaign on theITER divertor plasma-facing components(PFCs), i.e., outer vertical target (OVT),dome liner (DL) and inner vertical target (IVT)in stationary state and transient conditions.Both types of tests are carried out in theCEF 1 water loop at ENEA Brasimone.

Hydraulic tests in stationary state are aimed at determining the pressure drop of each component,verifying the balance of the parallel water flows and assessing possible conditions for the insurgenceof cavitation. The tests on the OVT and DL were successfully carried out in the last part of 2006.Figure A3.8 shows the OVT connected to the CEF 1 loop. Figure A3.9 reports the pressure dropsacross the OVT, experimentally determined at three different temperatures (20-50-100°C). Tests intransient conditions are aimed at evaluating the efficiency of discharging the activated water, not



Fig. A3.5 – Mockup after thermal fatigue testing (high heat

flux testing [HHFT] and CHF)

Fig. A3.6 – Mockup PH-S-39 B being tested in EDA-

BETA apparatus

Fig. A3.7 – The two mockups assembled in EDA-

BETA apparatus

EDA-BETA dimensions (Φ×l) 700×1200 mm

Max. power delivered by the resistor 41 kW

Max. thermal flux emitted by the resistor 0.65 MW/m2

Loop design temperature 140 °C

Max. CEF1 pump flow-rate 2×70 kg/s

Max. pump head 2×1.2 MPa

Table A3.I – EDA-BETA + CEF 2


drainable by gravity, into the divertor modules. The procedureto efficiently accomplish this task has been identified asconsisting of a first phase of draining by high-pressure gas,followed by drying of the residual water by low-pressure drygas. This part of the experimental activity requires up-gradingof the CEF 1 loop: most of work on the technicalspecifications and on the design and construction activitieshas been done and will be concluded in early spring 2007.ENEA Brasimone and the University of Palermo arecollaborating on validating a thermal-hydraulic code throughcorrelation with the experimental results for both types oftest. Once validated on the basis of the experimental results achieved, thecode will be used to predict the behaviour of the single components of theITER divertor as well as the integrated divertor cassette, in fully relevantoperative conditions and component geometry.

H permeation through EUROFER and heat exchangermaterial (Incoloy, Inconel)

In 2006 the PERI 2 device was modified. A more precise quadrupole wasadopted and the mixing-gas system, with a mass flow meter on the Ar line,a mass flow controller on the H/D line and a gas humidifier and humiditymeasuring system, was moved from the low- to the high-pressure side. Afterstart-up of the modified device, tests with deuterium were begun, using aratio of three between deuterium and water. The experiment gave noappreciable results: after a few seconds, there was a reduction in thepermeated hydrogen flux but, continuing the experiment, this effect wasannulled and the flux reached the steady-state value. Tests were performedwith EUROFER in accordance with the test matrix, using hydrogen instead of deuterium. This solution wasadopted as the new quadrupole demonstrated high precision in measuring hydrogen concentration, unlikethe old instrument. A precise range of water/hydrogen mixtures in which the permeation reduction factor(PRF) is appreciable was identified, and the campaign on EUROFER was concluded. Experimental resultsobtained in terms of PRF are reported in figure A3.10.

Formal trials for the new ITER divertor cassette refurbishment

Since the divertor cassettes need to be replaced and updated several times during the ITER lifetime,refurbishment of these components must be performed rapidly and with a high standard of safety. Toassess the feasibility of such refurbishment operations a test campaign consisting of two completeassemblies and disassemblies (fig. A3.11) of the three PFCs, also called targets, was performed during

43

20°C

80°C

50°C

100°C

y=0.0228x1.8223R2=1y=0.0188x1.8809R2=0.9998y=0.0171x1.9083R2=0.9997y=0.0174x1.881R2=0.9996

5.0

4.0

3.0

2.0

1.0

0.05 8 11 14 17 20

Water flow (kg/s)

Pre

ssur

e dr

op (

bar)

Fig. A3.9 – Pressure drops across OVT

PR

FRatio H2/H2O

0

10

20

30

6/3 20/3 35/3 45/3 55/3 60/3 75/3 85/3 110/3

Fig. A3.10 – EUROFER experimental results in terms

of PRF as a function of the ratio H2/H2O

Fig. A3.8 – OVT connected to CEF 1 loop

Fig. A3.11 – Removal of the inner

vertical target

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2006. The trials were aimed at validating the procedures already developed as well as evaluating thesuitability of the present cassette design (i.e., new ITER 2001 divertor cassette) for remote handling.According to the results of the tests, the assembly process appears to be better than thedisassembly process. In fact the tool used for pin extraction was not correctly dimensioned andhence target disassembling operations were carried out hands on. At present the tool design isunder revision. The other tools developed, such as the plasma-facing-component transporter(PFCT), the pin expansion tool (PET) and the drilling machine, fulfil the specification requirements.The activities were completed in July 2006.

A3.3 Breeder Blanket and Fuel Cycle

DEMO breeding blanket

Work continued on the development of the dual coolant lithium lead (DCLL) concept and thepossibility of having a vertical module segmentation (VMS) for the blanket [A3.6, 3.7]. The resultshave pointed out the potential of the DCLL blanket to operate in the required DEMO environmentwith allowable temperatures and stresses. The VMS studies showed a gain in reducing the electro-magnetic loads during disruption, therefore reducing the requirements for the support structure. Theresults of dimensioning of the supports and studies on the kinematics in the vessel showed that itmight be possible to replace the whole blanket using a reasonable number of ports. The ports arebeing studied in relation to the hypotheses on the DEMO magnets.

European Breeding Blanket Test Facility

Throughout 2006 ENEA was strongly involved in R&D activities for both the helium-cooled pebblebed (HCPB) and the helium-cooled lithium-lead (HCLL) test blanket modules (TBMs) to be tested inITER. The work was focussed on i) experimental activities related to the development of relevanttechnologies and ii) the design, construction and upgrading of the experimental facilities, which willallow ENEA to retain the EU leadership in the field of experimentation on TBMs.

The construction of the liquid metal loop was started in April 2006. The reference parameters, fixedin the design phase, are volumetric flow rate 0.03-0.9 m3/h; maximum temperature 550°C;minimum temperature 300°C; thermal cycling 400 s Tmax, 1400 s Tmin; liquid metal inventory in themodule 0.4 m3; liquid metal inventory in the loop, including the TBM, 0.6 m3; cover gas argon. Themain modifications foreseen to upgrade HEFUS3 are a new water heat exchanger of 900 kW and anew electric power supply unit of 1 MW, in order to provide 250 kW of electrical power to the firstwall and 750 kW to the breeding region of the TBM mockups. HEFUS3 will be equipped with a newHe compressor capable of reaching a maximum He flow-rate of 1.4 kg/s with a head of 0.9 MPa.Its installation is foreseen for late 2007. In 2006 the technical specifications for the HEFUS3upgrading were prepared. The conclusion of the activity, with the installation of the above-mentionedmodifications, is scheduled for the end of 2007.

Thermo-mechanical characterisation of HCPB mockup

The thermo-mechanical behaviour of the breeder and neutron multiplier pebble bed in reactor-relevant conditions is one of the main concerns in the design of the HCPB blanket for DEMO andthe TBM to be tested in ITER. Hence, experimental results and predictive models are of basicimportance in developing this blanket concept. During 2006 the HELICA mockup was dismountedand the OSi pebbles recovered. The pebbles were “filtered” and the production of powder, after 34thermal ramps, quantized in 4%. Scanning electron microscopy (SEM) examinations (fig. A3.12) ofthe pebbles showed that they kept their physical integrity. A new experimental setup was designedfor thermo-mechanical characterisation of the HEFUS3 experimental cassette of the lithium-




beryllium pebble bed (HEXCALIBER) mockup, designed andmanufactured to reproduce a portion of the former TBM-HCPBwith two OSi and two beryllium pebble bed cells, both heatedby couples of flat electrical heaters (figs A3.13). The mockup willbe tested in 2007 in the HEFUS3 facility, under appropriateadjustment of bed temperatures, temperature gradients,coolant temperatures, flow distributions and mechanicalconstraints, to assess the thermo-mechanical performance ofthe pebble beds under steady-state and cyclic-heat powerconditions. To perform the test campaign in safety, avoiding anypossible Be contamination, the whole experimental setup wasdesigned at a pressure of 2.0 MPa and a temperature of 500°Cand equipped with three independent helium circuits: one circuitfor the cooling plates of mockup, and two purge flow circuits forOSi and Be beds, a vacuum system, and a double oil guard.Each circuit will have units for filtering and monitoring the Bepowders. A preliminary study of the HEXCALIBER mockupthermo-mechanical behaviour under steady-state conditionswas performed in the framework of the benchmark exercise toselect the best constitutive model for thermo-mechanicalprediction of pebble bed behaviour under blanket-relevantconditions, among those developed by ENEABrasimone/University of Palermo, the Nuclear ResearchConsultancy Group (NRG) Petten and Forschungszeuntrum Karlsruhe (FZK). In particular, a realistic 3D finiteelement model (FEM) of HEXCALIBER (fig. A3.14), simulating a 1-cm-thick slice of the whole mockup, wasdeveloped. A realistic set of loads and boundary conditions was applied, taking into account naturalconvection with air, forced convection with helium coolant (T=300–400°C, p= 8 MPa) and distributedelectric heat generation within the heating plate electric resistors. A thermal contact model was implementedat the interface bed-wall and bed-heater, where no mechanical sliding was assumed. Poloidal plain strainwas assumed to simulate the continuity of the mockup in that direction. The thermal field obtained matchesthe prefixed goals, showing in each pebble bed the expected trapezoidal poloidal profile with the flat portionlocated in the pebble bed layerbetween the heating plates. Adecreasing radial profile from thecentre to the extremity of the bedcan be seen in each pebble bed.Maximum temperatures of 819and 563°C have been calculatedfor the OSi and the Be pebblebed, respectively. Analysis of themechanical volumetric strain fieldwithin the beds shows that theyexperience only compressivestrain states. The highestmechanical strains are reachedwithin the OSi pebble beds andare (≈0.17) one order ofmagnitude higher than in Bebeds.

[A3.6] C. Nardi, S. Papastergiou and A. Pizzuto, Development of DCLL blanket, ENEA Internal Report FUS-TEC BB MC R 0016 (2006)

[A3.7] C. Nardi, S. Papastergiou and A. Pizzuto, DEMO blanket segmentation, ENEA Internal Report FUS–TEC BB MC R 0017 (2006) Ref

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Acc.V Spot Magn Det WD Exp 500 μm20.0 kV 5.0 50x SE 15.9 823 PM13206 Li4SiO4 Helica 2>138 μm

Fig. A3.12 – SEM of HELICA OSi pebbles

Fig. A3.13 – HEXCALIBER mockup

+8.300e+02+7.934e+02+7.569e+02+7.203e+02+6.837e+02+6.471e+02+6.106e+02+5.740e+02+5.374e+02+5.009e+02+4.643e+02+4.277e+02+3.911e+02+3.546e+02+3.180e+02

NT11

Max +8.292e+02at node PART-1-1.15106Min +3.197e+02at node PART-1-1.958

A

A

z [m

]

T (°C)400 600 800

0.225

0.125

0.025

Fig. A3.14 – HEXCALIBER FEM model: thermal field and its poloidal profile along

the path A–A

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TRIEX loop for studyingtechnologies for extractingtritium from Pb-17Li

The first year of activity with theTRIEX loop, delivered toBrasimone at the end of 2005,was dedicated to loopacceptance tests andqualification of the main installedcomponents (pump, gas

saturator, gas extractor by packed column). The first test campaign with a test matrix agreed on byEFDA and other EU Associations will be performed in 2007. To verify the Pb-Li pump performance,the loop was operated without the stripping gas flowing in the expected operative Pb-Li flow raterange between 0.1 to 1 kg/s. Varying the Pb-Li mass flow rate, the attainment of 500°C asmaximum operative temperature was also evaluated to check the loop electrical heating system.Then, the Ar gas system injection was operated to check the Pb-Li levels in the saturator andextractor by using the gas mass flow control systems of the facility. After loop qualification the realexperimental activities will start with a first experimental test campaign and an optimised test matrix,obtained by adopting a factorial method developed by CEA to better exploit each test, optimise thetest para meters and consequently to reduce the total number of tests. Table A3.II reports the testmatrix approved by EFDA. The experimental activities will be concluded at the end of 2007.

Conceptual design of auxiliary systems for HCPB-TBM

The possibility to recover with high efficiency the tritium generated in the HCPB blanket as well asthe fraction permeated into the He main cooling system is one of the main objectives of the blankettest campaign planned in ITER. In summer 2006 ENEA was charged by EFDA with studying theselection and conceptual design of the tritium extraction system (TES) and coolant purificationsystem (CPS) for the HCPB TBM. For both systems the activity consists in determining the inlet gascomposition during the different ITER operational phases, examining all the technological optionsand selecting the most suitable and, finally, proposing a first conceptual design.

Both the TES and the CPS are based on the technology of physical adsorption on microporousmaterials in different system configurations (pressure temperature swing adsorption (PTSA), TSA,PSA), integrated with other systems which, depending on the process requirement, makes it possibleto reduce HTO in HT (Zn or Zn-Fe-Mn reactors) or, on the contrary, to oxidise HT to HTO (Cu2O-CuO).

Structural analyses during em loading

For the TBM with the HCPB concept, numerical models have been developed to take into accountthe presence of pebble beds during electromagnetic (em) transient structural analyses. The em forcedistribution increases to an asymptotic maximum and then drops exponentially to null. These loadscan produce oscillations in the TBM structures when the force disappears, or no oscillations if thedamping is large enough. Hence it is necessary to analyse the behaviour (stiffening and inertial) ofthe beds during such a quick transient load (30-100 ms), differently from the “low-velocity” modelsused up to now for thermal cycling modelling.

The presence of pebble beds inside the TBM is analysed though the definition of two representativesimplified models of the complete structure: 1) a submodel of the grid structure; 2) a submodel of abreeder unit. The steel components are assumed to behave linearly elastic, while the modifiedDrucker-Prager model is implemented for the mechanical characterisation of the pebble layers. Theresults of oedometric tests for the beryllium pebble beds are used to calibrate the parameters ofsuch a constitutive relationship. On the basis of the numerical simulation it is possible make the



Test Temperature Pb Li flow rate Stripping Ar flow rateno (°C) (kg/s) (Nl/h)

1 450 0.2 10

2 450 0.5 100 (150)

3 450 0.35 55 (80)

4 450 0.2 100 (150)

5 450 0.5 10

6 450 0.35 55 (80)

Table A3.II – EFDA-approved text matrix


following considerations: a) The pebble layers have a moderate effect on the structural behaviour of theTBM components if shear deformation is dominant. In this case, the volume reduction of the TBM cavitiesand, thus, the compaction of the pebble beds are negligible. As a consequence, the stress state in thesteel frame undergoes minor variations when the granular filler is considered in the numerical model. b)When the deformation of the steel frame during em loading acts in such a way as to produce compactionof the pebble beds, their effects become much more significant: the presence of a filler material producesa sensible increase in the structure stiffness and, at the same time, the stress field is redistributed withinthe steel frame. Usually, when the pebble beds are included in the model the stress intensity is less criticalcompared with the case of the empty frame (without pebble material). Nevertheless, em loading can inducehigh stresses in regions not designed to bear them.

VDS catalyst tests

Samples of Plexiglas, Polyvinyl chloride, vacuum pump oil and Teflon were burnt at 200°C in a 1 m3 oven(fig. A3.15) and the combustion fumes were sent onto catalytic beds consisting of platinum on Al2O3 (Escat26 furnished by Engelhard). The aim was to reproduce the case of a fire in the tritium laboratory of ITER

47

Fig. A3.15 – Materials used in the combustion tests: a-b) Plexiglas, c-d) PVC, e-f) vacuum pump oil with Teflon

A

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e and to study the poisoning of the catalyst of thevent detritiation system (VDS). The test results

show that the combustion fumes of PVC, pump oil and Teflon could affect the Pt-based catalystefficiency even if, under the operating conditions of the VDS, all the tritiated gases (HT) areconverted into tritiated water [A3.10].

Permeator tubes

The PERMCAT reactor module designed by ENEA has been completed (fig. A3.16). This device hasa special mechanical design in which two pre-tensioned metal bellows avoid any compressive andbending stresses of the thin-walled (50 μm), long (500 mm) Pd-Ag permeator tube produced viacold rolling and diffusion welding of metal foils [A3.8, A3.9].

A3.4 Magnet and Power Supply

ITER magnet casing welds

The tests performed at ASG Superconductors Genoa to verify the use of electron beam weldingprocedures to perform the root weld for the ITER magnet casings (in AISI 316 LN modified with highnitrogen content) showed that, using the welding apparatus in ASG and the proposed weldingprocedures, it is not possible to weld a 40-mm thickness of this material [A3.11].

ITER pre-compression ring fibreglass composite material

A new batch (VR 5) of unidirectional fibreglass composite has been produced in the new kettle. Theincrease in the active length of the kettle allowed the production of 650-mm-long samples, whichwere tested with the use of the grip system (45’ fibreglass grips kept in place by 15 Inconelcompression rings in) at room temperature (RT) and 77 K (5 samples per temperature). The resultsshowed that the mean value of the ultimate tensile strength was 2200 MPa at RT and 2766 MPa at77 K. In both test sets the dispersion in the values of the mechanical characteristics (ultimatestrength, elasticity modulus and fracture elongation) was very low, the maximum being lower than3% of the mean value [A3.12]. Relaxation tests are envisaged for 2007.

High-frequency/high-voltage solid-state modulator for ITER gyrotrons

Activities regarding construction and testing of the solid-state modulator (EFDA contract 02-686)were successfully completed during the first months of 2006. At the same time, a new task wasstarted on design support and digital simulation of the entire power supply system for the Europeancollector depressed potential (CDP) gyrotron test.

A3.5 Remote Handling and Metrology

In the sharing of the in-kind contributions to ITER, the EU is to procure the in-vessel viewing andranging system (IVVS), which has to be able to provide sub-millimetric 3D images inside theactivated machine. Results of the relative R&D performed during the last six years have shown that



Fig. A3.16 – View of the PERMCAT module (above) and the

Pd-Ag thin–wall permeator tube (below)


the IVVS probe (fig. A3.17) developed by ENEA is the only device suitable for this purpose and able toproperly operate in the actual ITER environment (table A3.III). The IVVS is a coaxial system that soundsthe target by means of an amplitude modulated laser beam. Amplitude and phase shifting of the receivedpart of the backscattered beam are analysed by dedicated radar electronics in order to simultaneouslyperform both target viewing and ranging actions. To fully demonstrate the IVVS performance (EFDAcontract 05-1256) parametric testing of the IVVS probe on full-scale prototypes of an ITER first-wall panel(FWP) and divertor vertical target (DVT) was performed in 2006. The aim was to characterise the probe onrealistic targets at different distances (in the range 1-8 m) and at different viewing angles (0°-70°). The DVTsample had been previously subjected to thermal stresses simulating thermal loads on the divertor duringITER operation.

Figures A3.18 and A3.19 show some details of the test results for the ITER FWP and DVT samples. It can

Ref

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Temperature 250°C

Vacuum 10-9 mbar

Magnetic field 5 T

γ Radiation (rate/total) 1.5 kGy/h; 5 MGy

Viewing&ranging accuracy << 1 mm

Table A3.III – IVVS operating conditions

Fig. A3.17 – IVVS Probe

[A3.8] S. Tosti et al., Fusion Eng. Des. 82, 153 (2007)

[A3.9] S. Tosti et al., Improvements to the mechanical design of the PERMCAT component - construction of membrane tubes - Final Report,ENEA Internal Report FUS TN BB-R 021 (2006)

[A3.10] F. Borgognoni et al., Experimental investigation of vulnerability of VDS catalyst to poisoning by species released during fire - IntermediateReport, ENEA Internal Report FUS TN BB-R019, 30 (2006)

[A3.11] C. Nardi, Final report on EB welding activities, ENEA Internal Report FUS-TEC MA R 023 (2006)

[A3.12] L. Bettinali, C. Nardi, Final report on short term tests on monodirectional fiber composite for ITER rings, ENEA Internal Report FUS-TECMA R 021 (2006)

Δ= -1 mm Δ= -10 mm

3759

3756

3753

3750

3747

492313692324616123080

-200 -100 100 200 3000

x-axis parallel to the plate (mm)

1.0

1.2

1 2 4

a)

b)

Fig. A3.18 – 3D inspection testing on ITER

FWP sample (d=3,75 m; θ= 0°; pixel stay

time=3 ms): a) submillimetre viewing of

FWP detail compared with a standard

resolution chart; b) ranging measurement

(σ, standard deviation 140 μm); c) 3D

image: merging, viewing and ranging data,

simultaneously acquired

b)

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be noted that therequested viewingand ranging per -formances are fullymet for both. Theviewing performancewas compared with astandard resolutionchart, while rangingaccuracy wasidentified as thestandard deviation ofall the rangingmeasure ments. TheIVVS probe wascharacterised bydefining rangingaccuracy vs thebackscattered powerreceived by the

probe. The experimental results fully comply with the theoretical expectations. The ITER operator willhave a friendly tool to easily evaluate the expected accuracy according to the target position andcharacteristics. Possible probe modifications (increasing laser power and modulating frequency)were identified in order to upgrade the present performance by about a factor of 10.

A3.6 Neutronics

Quality assurance for neutronics analysis for ITER

Quality assurance (QA) procedures for neutronics analyses (task TW5-TDS-NAS1–D1) were drawnup in collaboration with the ITER Responsible Officers for Neutronics and for the Management andQuality Programme. The final version of the procedures, applicable to the ITER Central Team and toexternal suppliers, was issued on the basis of feedback received, and loaded on the ITERDocumentation Management (IDM) system [A3.13]. As a test case the procedures were applied ina neutronics task order implemented by EFDA on the ITER diagnostic plug analysis, and theapplication was monitored. A series of actions was also undertaken to assess and provideadequate instruments for the QA procedures. First, the status of the MCNP brand model forneutronics analyses of ITER was reviewed. It was found that there were many outdated models thatcontained significant differences as they had been developed for various specific purposes, so anup-to-date reference model was produced and made available, and the reference materialsspecified in the model were reviewed. According to QA procedures, computer software forneutronics calculations has to be verified and validated prior to use. Codes were identified that hadalready been verified and validated during the ITER EDA R&D activities and can be used in the ITERneutronics analyses and calculations. The related documentation was collected. However, othercodes, or new versions of codes, may be developed for specific purposes: a verification/validationprocedure was worked out for these cases and applied to code packages under development, suchas CAD-MCNP interfaces, Attila code and D1S, R2S package (MCNP-FISPACT coupled) for doserate calculations. Three separate validation efforts were launched for the Fusion Evaluated NuclearData Library (FENDL)-2.1, selected as the reference library for ITER. ENEA and the Japan AtomicEnergy Agency (JAEA) conducted the analysis of experimental benchmarks performed at theFrascati Neutron Generator (FNG) and the Fusion Neutron Source (FNS), respectively, during ITEREngineering Design Activities (EDA), and FZK conducted a computational benchmark on a simplifiedITER geometry.



Thermally stressed zones

795.8

605.1

mm

749.0

604.1

mm

306.0 pixels

342.0 pixels294.0 pixels

348.0 pixels

Fig. A3.19 – Viewing and ranging test on ITER DVT metal side (d=2 m; ranging

accuracy standard deviation σ < 1 mm)


Finally, the ITER Nuclear Analysis Report (NAR) was reviewed and the parts that need to be updated wereidentified. As a general result, it was found that new calculations are needed for many components, takinginto account the present design. A table of contents has been written for the next issue of the NAR.Compared to the previous NAR structure, more emphasis will be given in the new issue to the componentsrather than to the models used.

ITER systems: nuclear design

The activity was focussed on interfaces for divertor sensors and optical elements in the divertor cassetteand lower ports, the design and integration of the sensors and optical access and on a review of divertorintegration issues for the various diagnostic systems. In particular, work was carried out on the interfaceand integration issues of the new “Divertor 2006 Design” of the neutron diagnostics (lower vertical neutroncamera and divertor neutron flux monitors) of the optical systems (divertor impurity monitor and divertorThomson scattering) and the residual gas analyser systems, taking into account possible locations in ITERdivertor, detectors/techniques, vacuum and magnetic field interferences, radiation, cooling andcabling/power supplies. Calibration issues/schemes of the neutron systems and related integrationengineering aspects were studied to identify the ITER in-situ neutron calibration procedures. The rationale,requirements, specifications concerning the neutron test area (NTA) and the NTA-hot cell systemintegration issues were reviewed. The NTA is a laboratory for inspection trials, calibration, commissioning,cross checking and support of neutron diagnostic sensitive devices and equipment during all thefunctioning periods (assembly, operation, shutdowns, maintenance) of ITER [A3.14, A3.15].

TBM HCPB and HCLL neutronics experiments

In 2006 the neutronics experiment on a mockup of the European Union TBM, HCPB concept wascompleted [A3.16, A3.17]. The aim was to validate the capability of nuclear data to predict nuclearresponses, such as the tritium production rate (TPR), with qualified uncertainties. The experiment wascarried out at the FNG 14-MeV neutron source in a collaboration between ENEA, the Technical Universityof Dresden (TUD), FZK and the Joseph Stefan Institute of Ljubljana, with the participation of JAEA underthe International Energy Agency (IEA) Implementing Agreement on a Co-operative Programme on theNuclear Technology of Fusion Reactors. A slight underestimation was found in the calculation of tritiumproduction in the range (1–C/E)~5...10% on average. The resulting total uncertainties on C/E for the TPRprediction were about 9 – 10% at 2σ level [A3.18]. The observed underestimation of the measured tritiumproduction by less than 10% on average is therefore at the lower bound of the assessed uncertaintymargin. Behind the mockup, the fast neutron flux (E>1 MeV) was found to be overestimated bycalculations by about 10–20%, while the gamma-ray flux is underestimated by about 10-20% [A3.19,A3.20]. The slow neutron flux investigated by time-of-arrival spectroscopy is also underestimated by

[A3.13] P. Batistoni, Quality assurance in neutronic analyses (May 2006), https://users.iter.org/users/idm?document_id=ITER_D_23H9A4

[A3.14] G. Bonheure et al., Nucl. Fusion 46, 725 (2006)

[A3.15] A. Costley et al., The design and implementation of diagnostic systems on ITER, presented at the 21st Inter. Atomic Energy Agency (IAEA)Fusion Energy Conference (Chengdu 2006)

[A3.16] P. Batistoni et al., Fusion Eng. Des. 81, 1169 (2006)

[A3.17] U. Fischer et al., Neutronics and nuclear data for fusion technology - recent achievements in the EU programme, presented at the 21st

IAEA Fusion Energy Conference (Chengdu 2006)

[A3.18] P. Batistoni et al., Neutronics experiment on a HCPB breeder blanket mock-up, presented at the 24th Symposium on Fusion Technology- SOFT-24 (Warsaw 2006), accepted for publication in Fusion Eng. Des.

[A3.19] K. Seidel et al., Measurement and analysis of neutron flux spectra relevant to the tritium breeding capability in a neutronics mock-up ofa test blanket module for ITER, presented at the Int. Workshop on Fast Neutron Detectors and Applications (Cape Town 2006)

[A3.20] K. Seidel et al., Measurement and analysis of the neutron flux spectra in a neutronics mock up of the HCPB test blanket module,presented at the 24th Symposium on Fusion Technology - SOFT-24 (Warsaw 2006), accepted for publication in Fusion Eng. Des. R

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about 20%. The last results are consistent with the weak underestimation of the tritium breedingalso found for the main block. According to these results, the shielding performance of the mockupis predicted within ±20% accuracy. The tritium production (most of which coming from 6Li) is mainlysensitive to the 9Be cross sections for elastic scattering and, to a lower extent, for the 9Be (n,2n)reaction. The sensitivity/uncertainty analysis showed that the TPR from 6Li changes by about 2%per % change of the 9Be elastic scattering integral cross sections, but the sensitivity with respect tothe angular differential cross section dσ/d Ω could be higher [A3.21, A3.22]. These results indicatethat the angular differential cross section for 9Be elastic scattering may require further improvement.Results from the HCPB mockup experiment implied that for the HCPB TBM in ITER the tritiumproduction is underestimated by the calculations based on the European Fusion File (EFF) andFENDL nuclear data (used in this analysis) by less than 10% on average, at the lower bound of theassessed uncertainty margin, and that the neutron and gamma ray shielding performance ispredicted within ±20% accuracy [A3.23]. The pre-analysis of the next experiment on a mockup ofthe TBM HCLL has also been completed.

Experimental validation of neutron cross sections for fusion-relevant materials

The neutron-induced decay heat on samples of molybdenum (99.99 %) irradiated at FNG in a first-wall-like neutron spectrum was measured (European Activation File [EAF] Project). Threemolybdenum samples were irradiated for about 3.5 h at FNG. One sample was monitored with theENEA decay heat measuring system where gamma and beta decay heats are simultaneously



106105104103102 106105104103102

106104102 106104102

C/E

C/E

1.3

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

Decay time (s)

Decay time (s) Decay time (s)

Beta heat

Error bars include onlyexp. uncertanties

1.05

1.15

0.85

0.95

0.75

C/E

C/E

1.1

1.0

0.9

0.8

0.7

0.6

0.5

Decay time (s)

Gamma heat

1.05

1.15

0.85

0.95

0.75

0.65Error bars include only exp. uncertanties

Per

cent

nuc

lide

heat

con

trib

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100

10

1

0.1

Decay time (s)

Beta heat

Mo91Mo99

Nb98mNb97

Nb96Zr97

Tc99m

106105104103102 106105104103102

Per

cent

nuc

lide

heat

con

trib

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n

Gamma heat

100

10

1

0.1

Decay time (s)

Mo91Nb97Nb96

Mo99Mo101Mo93m

Y89mTc99mNb92m

Nb98mZr89Nb95

Fig. A3.20 – Results from decay heat measurements for beta and gamma. Inserts: experimental

uncertainties

Fig. A3.21 – Beta and gamma heat nuclide contributions - 65 nm range


measured. The other two samples were monitored with HPGe detectors. The decay times studied wentfrom a few minutes up to some days after irradiation. Comparison between experimental data and EASYpredictions is satisfactory for both beta and gamma heat (fig. A3.20). A discrepancy (C/E=0.85±0.1 experr.) found in the gamma heat for short decay times could be due to the reactions 92Mo(n,2n)91Mo,92Mo(n,2n)91mMom(IT)→91Mo, and/or to decay data of 91Mo. This nuclide is responsible for about 90% ofthe heat produced for a short decay time (<1000 s; fig. A3.21). With gamma spectroscopy it was possibleto identify radionuclides and thus the nuclear reactions that mainly contribute to the induced activation. Intotal seven reactions were identified as being responsible for more than 99% of the heat produced in themeasured decay time. For these reactions EASY-2005 data are adequate to reproduce the experimentalresults obtained at FNG.

A3.7 Materials

Flat-top indenter for mechanical characterisation

Indentation is a mechanical test used to investigate the elasto-plastic behaviour of materials. The portableapparatus developed at ENEA (fig. A3.22) makes it possible to measure in a continuous way the variationin the load as a function of the indentation depth. From the curve of load and unloading information about

the elasto-plastic behaviour of the material, namely Young’smodulus, the yield stress and the strain hardening exponent can beextracted. In 2006 tests were carried out at high temperature (about440°C) on ferritic-martensitic steel F82H (fig. A3.23). The cylindricalindentation was simulated with the use of a data bank obtained withfinite element computations. By applying dimensional analysis tothe data bank it was possible to solve the direct problem and alsothe reverse problem, which consists in estimating the elasto-plasticparameters from a load-penetration curve. Mechanical modificationof the apparatus will allow creep and relaxation tests.

[A3.21] D. Leichtle et al., Sensitivity and uncertainty analysis of the tritium production in the HCPB breeder blanket mock-up experiment,presented at the 24th Symposium on Fusion Technology - SOFT-24 (Warsaw 2006), accepted for publication in Fusion Eng. Des.

[A3.22] H. Henriksson et al., The EFF project status and the NEA nuclear data services, presented at the 24th Symposium on Fusion Technology- SOFT-24 (Warsaw 2006), accepted for publication in Fusion Eng. Des.

[A3.23] A. Klix, Measurements of neutron spectra and tritium production rates in an Iter TBM mock-up irradiated with 14-MeV neutrons,submitted to Fusion Sci. Technol. R

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Fig. A3.22 – Portable indenter

1200

800

400

0

T=25°CT=100°CT=185°CT=333°CT=440°C

0 100 200 300 400

Load

(N

)

Indentation depth (mm)

Fig. A3.23 – Indentation

curves for the steel F82H

with cylindrical indenter

of φ=0.7 mm

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A3.8 IFMIF

Remote handling of the back-plate bayonet concept – bolted solution

The reference International Fusion Materials Irradiation Facility (IFMIF) target design is based on theconcept of a replaceable back-plate. At present two different design options for the back-plate

replacement are under investigation: thereference design system, i.e., the so-called cutand re-weld concept proposed by the JapaneseIFMIF team, and the alternative solutiondeveloped in Europe and known as the back-plate bayonet concept. The latter concept isbased on the possibility of replacing the back-plate while working laterally to the target, thussimplifying the sequence needed to perform theoperations and, as already demonstrated,reducing back-plate-replacement operationaltime. In addition the bayonet concept has amajor advantage in that the material for finaldisposal is reduced. Two prototypes of the back-plate bayonet concept were manufactured in2002. The first prototype is provided with aclosing system based on a skate system andhas already been successfully tested, whilst thesecond (fig. A3.24) is characterised by a closingsystem consisting of bolted closure. Theexperimental activities carried out on the secondprototype were aimed at evaluating its suitabilityfor remote handling (RH). Comparison of the twoprototypes was performed from the RHviewpoint.

In particular, the activities were articulated asfollows: development of the installation andremoval procedures; modification of theprototype; adaptation of the bolting tool, RHtrials themselves; post-analysis of results. TheRH activities for the target prototype wereexecuted in the ENEA Brasimone divertorrefurbishment platform (DRP) and weresuccessfully completed in July 2006.

Lithium corrosion and chemistry:LIFUS III facility

In the framework of the key action phase ofIFMIF development, the activities carried outduring 2006 included corrosion/erosion testingof AISI 316 and EUROFER 97 in IFMIFrepresentative conditions; experimentalvalidation of the lithium purification strategy,based on a single cold trap and two hot trapshaving specific getters for nitrogen andhydrogen; functional validation of the



Fig. A3.24 – IFMIF back-plate bayonet concept

based on bolted closing system

Fig. A3.25 – New em pump for LIFUS III: a) initial

phase of mounting; b) final phase


performance of the resistivity-meter for lithiumimpurities, developed in collaboration with NottinghamUniversity. These activities have to be performed in theLIFUS III loop, which will be the first liquid metal loop atBrasimone to have liquid lithium as process fluid. Thewhole loop was refurbished because the previouslychosen canned pump failed continuously and had tobe substituted with an em pump (fig. A3.25). Due to thestrong reactivity of Li with damp air and water, stringentsafety measures were carried out. In addition, newpipes were installed, the test section was modified toenhance the safe manipulation of the corrosionspecimens, the gas purification was enhanced byinterposition of a specific on-line getter, a glove boxwas installed, the data acquisition software wasadapted, the experimental hall was refurbished to meetthe safety requirements, and the personnel were trained to deal with lithium safety issues. Moreover thedesign calculations were revised to match new pump conditions. The complete thermo-mechanicalverification of the piping was successfully performed by the ANSYS code. Similarity calculations werecarried out to adapt the pump performance to the loop conditions in order to find a new referencehydraulic working point (fig. A3.26).

Preliminary remote handling handbook for IFMIF facilities

A preliminary remote handling handbook (PRHH) is to be produced for the target and test facilities. It isbased on the work already done and on the documentation available. So far, apart from the introductiongiving a description of IFMIF together with the methodologies adopted, the work has been focussed on 1)defining a set of rules to distinguish components requiring RH maintenance from those that can bemaintained hands on; 2) identifying components requiring RH maintenance (not completed); 3) developingRH procedures for each component; 4) evaluating the area accessibility and interference with othercomponents and 5) defining the technical requirements for the devices and equipment to be used for theRH operations. The following components and devices have already been studied in the target and in thetest facilities:

1. Target assembly and replaceable back wall: both concepts (cut & reweld option and bayonet option)were studied and compared. The procedures for back-wall replacement were already known as well asthe equipment and devices to perform these operations. A preliminary study for the feasibility of back-wall replacement through a lateral window was also performed and will be included in the PRHH.

2. Replacement of the quench tank and other components from the target area.

3. Main Li loop components have been and, still are, under investigation.

4. Requirements for the main devices and tools have been defined: robotic arm and bolting tool for thebayonet concept; common manipulator system (CMS); transporter for the target assembly system. (Nodata are available for the YAG machine).

5. The general layout of the access cell of the test facility has been defined. (The path for the coolingsystems is still missing).

6. The general procedures for the vertical test assembly (VTA) replacement from the test cell, includingseparation and transportation of the test modules in the test module handling cell, have beencompleted.

7. Requirements for the main devices to be installed in the access cell have been defined: the UniversalRobot System (gantry crane), the support for the removal of the test modules and the transporter of thetest modules from the access cell to test module handling cell.

The work is expected to be completed by the end of June 2007.

55

Calculatedoperational point

Pump interdiction area

Line of minimumvelocity (10 m/s)

open valvevalve 67% open

valve 33% openV=300 V

V=340 VV=380 V

Bar

Liter/min

4

3

2

1

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-10 10 20 30 40

Fig. A3.26 – Re-calculated operational point

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Inventories and dose rates induced by deuterons and neutrons in theaccelerator system

ANITA-DEUT is the newly developed deuteron activation code package dealing with deuteron-induced transmutation and activation. The code can work with two deuteron cross-section libraries:the first based on the ACSELAM library; the second, on the file EAF_D_GXS-2005.1 of the EASY-2005-1 system. A methodology approach was set up to calculate deuteron/neutron-induced decaygamma sources and evaluate dose rates along the accelerator line because of deuteron beamlosses. The first step in the sequence consists of deuteron and secondary-neutron transportcalculations via the MCNPX code (version 2.5b). The deuteron and neutron spectra obtained areused in ANITA-DEUT and ANITA-IEAF activation codes to calculate the radioactive inventories ofmaterials and the corresponding decay gamma sources, which are then used for gamma transportcalculations via the VITENEA-IEF/SCALENEA-1 and MCNP-4C2 code systems to obtain the beam-off dose rates around the various parts of the IFMIF accelerator (i.e., radiofrequency quadrupole(RFQ) and drift tube linac (DTL). The decay gamma dose rates do not represent a hazard source forworkers (maximum value 5.6×10-2 μSv/h on the surface of the RFQ section 10) [A3.24]. Preliminarycalculations were performed for the last tank of the DTL with source deuterons of 40 MeV,considering a deuteron current loss of 130nA (8.11×1011 d/s). On the basis of this value, the beam-off total dose rate around the DTL is less than 10 μSv/h at 1 day’s cooling time.

Inventories and dose rates induced by deuterons and neutrons in the coolingsystem

The structural materials of the high-energy beam transport (HEBT) section can be activated bydeuterons due to beam losses, by secondary neutrons produced by deuteron-induced nuclearreactions and by back-stream neutrons coming from the lithium target. The deuteron source energyis 40 MeV. HEBT activation due to neutrons was evaluated through the MCNP-4C2 code with theMcEnea neutron source, which is based on the measurements of neutron emission spectraproduced in Li(d,n) reactions for Ed=40 MeV performed at the Cyclotron and Radioisotope Center(CYRIC), Tohoku University, Japan. Preliminary calculations were performed, considering a deuteronbeam-loss current of 865nA (5.4×10-2 d/s). With this value the most relevant contribution to decaygamma dose rates in the area around the HEBT is due to the activation induced by lost deuterons(about 70%). The dose rate contribution of back neutrons is higher than that caused by secondaryneutrons due to beam losses.

A3.9 Safety and Environment, Power Plant Studies andSocioeconomics

Failure mode and effect analysis for the European test blanket modules

A failure mode and effect analysis (FMEA) was done to study possible safety-relevant implicationsarising from failures in the HCPB [A3.25] and HCLL [A3.26] TBMs for ITER. For both modules, sixpostulated initiating events (PIEs) were selected for deterministic assessments:

• FB1 (loss of flow in a TBM cooling circuit because of circulator/pump seizure).

• LBB1 (loss of TBM cooling circuit inside breeder blanket box: rupture of a sealing weld).

• LBO3 (loss of coolant outside vacuum vessel because of rupture of tubes in a primary TBM-HCS HX).

• LBP1 (loss of coolant outside vacuum vessel because of rupture of a TBM cooling circuit pipeinside port cell).

• LBV1 (loss of TBM cooling circuit inside vacuum vessel: rupture of TBM-FSW),

• TBP2 (small rupture from "TBM - tritium extraction system" process line inside port cell).




Failure mode and effect analysis for remote handling transfer systems of ITER

A FMEA at component level was done to study possible failures while performing remote handling (RH)operations [A3.27]. Two safety-relevant PIEs were selected: 1) break in “vacuum vessel + cask” isolatingboundary during RH operations, inducing release of radioactive products (fraction of dust and T implantedin vessel) into the port cell; 2) cask stop and leakage during RH transportation of divertor cassette to hotcell, inducing release of radioactive products (fraction of dust and T implanted in transported components)into the gallery. Deterministic analysis could be required to evaluate the response of the safety systems(e.g., efficiency of ventilation systems, isolation of heating, ventilation and air conditioning [HVAC] system)and effectiveness of rescue operations in mitigating the consequences and risks for workers. Complianceof the design features with the safety limits in the case of a fire triggered on board the transporter shouldbe required. Some concerns on recovery scenarios should dust or tritium be released inside the port cellor gallery could arise from the use of the air cushion transportation system. Accident rescue scenarios werealso identified by the FMEA and grouped in seven families.

Validation of computer codes and models

New contributions were obtained for validation of the activation code package ANITA-2000 against theKarlsruhe Isochronous Cyclotron (KIZ) and ENEA FNG experiments [A3.28, A3.29]. In the KIZ experimentsa saturation thick beryllium target was irradiated by 19-MeV deuterons. Samples of vanadium alloys, nickel,copper, lithium orthosilicate, EUROFER 97 and tungsten were irradiated. Specific activities in Bq/kg foreach sample material for several gamma ray emitting activation products were obtained and comparedwith the calculation. ANITA-2000 handled satisfactorily the activation channels induced by neutrons with asmooth continuum spectrum. The discrepancies between calculated and experimental (C/E) activity valuesare in the range 10-20%. The results of irradiation of samples of molybdenum and tantalum at the 14-MeVFNG neutron source were also compared with ANITA predictions. For molybdenum the agreementbetween C/E beta decay heats is good (within 10%) for all cooling times, while it is within 15% for thegamma decay heats; for tantalum the agreement is very good (within 2%) for all cooling times for the betadecay heat and lower than 10% for the gamma decay heat.

Time factors to be used for the JET shutdown dose-rate evaluation [A3.30, A3.31] in the direct one-step(D1S) method were obtained with the ANITA-2000 code (FENDL/A-2.0 activation data library). The ANITA-2000 calculations were performed using the data related to a) the JET materials composition for thedetector positions D1 (irradiation end) and D2 (Geiger Müller tube); b) the irradiation scenarios (DD and DT);

[A3.24] D.G. Cepraga, M. Frisoni and G. Cambi, Evaluation of activation inventories and dose rates induced by deuterons in the IFMIFaccelerator system, ENEA Internal Report FUS-TN-SA-SE-R-146 (2006)

[A3.25] T. Pinna, Failure mode and effect analysis for the European Helium Cooled Pebble Bed (HCPB) test blanket module, ENEA InternalReport FUS-TN SA-SE-R-152 (2006)

[A3.26] T. Pinna, Failure mode and effect analysis for the European Helium Cooled Lithium Lead (HCLL) test blanket module, ENEA InternalReport FUS-TN SA-SE-R-155 (2006)

[A3.27] R. Caporali and T. Pinna, Failure mode and effect analysis for remote handling transfer systems of ITER FEAT, ENEA Internal Report FUS-TN SA-SE-R-156 (2006)

[A3.28] V. Massaut et al., Validation of European computer codes used for fusion safety analysis, presented at the 8th IAEA Technical Meetingon Fusion Power Plant Safety (Wien 2006)

[A3.29] D.G. Cepraga, G. Cambi and M. Frisoni, ANITA-2000 activation code packages: 2005 validation effort against Karlsruhe Isocyclotron andFNG-ENEA experiments, ENEA Internal Report FUS-TN-SA-SE-R-136 Rev.1 (2006)

[A3.30] L. Petrizzi et al., Benchmarking of Monte Carlo based shutdown dose rate calculations applied in fusion technology: from the pastexperience a future proposal for JET 2005 operation, Fusion Eng. Des. 81, 1417-1423 (2006)

[A3.31] M. Angelone et al., Neutronics experiment for the validation of activation properties of DEMO materials using real DT neutron spectrumat JET, Fusion Eng. Des. 81, 1485-1490 (2006) R

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c) the relevant isotopes considered for the shutdown dose rates at the selected JET D1 and D2positions [A3.32]. A first analysis was performed by considering the JET irradiation scenario (DD andDT) up to March 2004. The gamma material decay sources were obtained (1.5 y cooling time) andused in SCALENEA-1 to get the shutdown dose rate (September 2005, measurement time) in theD1 position. The C/E ratio obtained is 1.015.

Finally, updated analyses were carried out on the possibility of clearance of the ITER vacuum vesselmaterials, considering the new (August 2004) unconditional clearance levels given in the IAEA SafetyGuide RS-G-1.7. The relevant results from the updated analysis [A3.33] are:

• The 430 ferritic steel and the SS 304B4 steel of the outboard vacuum vessel zone (VVSHDO) areclearable after a longer time compared with the previous analysis results when the TECDOC-855clearance level data were employed. This is particularly true for the SS 304B4 steel, whichbecomes clearable only after about 6000 years (with respect to the 90 years of the previousanalysis).

• The remarkable change for the VVSHDO(2) – SS 304B4 steel is due to the highest contribution(at 100 years’ cooling time) from the Ni-63, which is now (i.e., with the RS-G-1.7) about 40%compared to the older (i.e., with the TECDOC-855) value of about 10%.

Dust removal experiments in STARDUST

Dust removal inside the plasma chamber is a concern with regard to machine performance and tosafety. Experiments were carried out in the ENEA STARDUST facility in 2005 [A3.34] by using astream of air in the volume representing the vacuum vessel in which characterised carbon, tungstenand stainless-steel dusts were placed. The capacity of dust mobilisation by means of the air inflowwas between a few percent and 100%, depending mainly on the type of dust and on the kind of

deposition (heap or flatlayer). Mobilisation is moreeffective in cold conditions.The efficiency of the systemto capture dust on the filterreached a maximum ofabout 7.5% for carbon in thegeometrical configuration ofthe STARDUST facility.Heavy dusts such as SS316and W did not reach the filter.Figure A3.27 shows thecarbon dust results. Thetested technique of removingthe vacuum vessel dust haslow efficiency in thecollection of powderremoved from the vessel anddeposited on appropriatesurfaces (i.e., filters). The use

of an air stream directly on the dust deposit can improve the effectiveness of the removal but, tocollect a significant amount of dust in the filter, the pressure in the volume must be increased, sothat conditions which are dangerous for the internal equipment can be avoided.

Feasibility study of a torus-shaped facility for dust mobilisation studies

A feasibility study was carried out for a toroidally shaped facility for dust mobilisation and removalexperiments [A3.35]. The facility, named STARDUST-U (fig. A3.28), should facilitate the extrapolation



1 2 3 4 5 6 7 8 9101112

%

150

150125

755025

0

T=20°C T=20°C

%

1 2 3 4 5 6 7 8 9 1011120

2

4

6

8

T=50°C

%

1 2 3 4 5 6 7 8 9101112N. test

30

2025

35

1510

50

N. test

T=50°C

1 2 3 4 5 6 7 8 9 1011120

2

4

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8

%

Fig. A3.27 – Mobilisation factor and capture factor for carbon dust in hot and

cold conditions (red 10 m, blue 30 m, yellow 1 h


to ITER of the experimental results obtained duringtests in which dusts are mobilised. It allows themonitoring, by laser diagnostics, of the dustconcentration evolution in the different zones of themachine. The windows will make it possible to viewthe dust mobilisation in the zone with laser systems ifthe concentration is below 1000 particles/cm3.Although this concentration can be far fromaccidental conditions in the ITER device, thedynamics of the phenomena during mobilisation can be helpful in extrapolating the results at higherconcentrations, mainly to test the performance of the dust simulation codes.

The estimated cost of the whole facility is about 16,600 Euros (2006 evaluation).

Post-accident occupational exposure and radioprotection

The objective of this study [A3.36] was to provide an indication of occupational radiation exposure (ORE)consequences associated with post-accident recovery operations. The accident analysis resultsdocumented in Volume VII of the ITER Generic-Site Specific Safety Report (GSSR) were used. The focuswas on the actions that are needed to restore the machine to the operational state, and on the potentialimpact of the actions on the collective worker dose. Even the release of one gram of tritium (in the form ofHTO), one gram of activated corrosion products, or one gram of tokamak dust can cause significantcontamination concerns. Airborne contamination is not a significant problem, as this can be easily removedby the building/room ventilation system working in conjunction with the re-circulating detritiation systemand exhaust detritiation system. Surface tritium contamination is a bigger concern, as this takesconsiderably more time to reduce, to acceptable levels, using the same systems. Surface aerosols fromactivated corrosion products (ACPs) and dust contamination could be an even bigger concern if watersprays are either not available, or not effective, for washing the deposited aerosols and dust in the activedrain system.

Integration of design modifications (in Rapport Préliminaire de Sûreté) to tritiumbuilding and detritiation system

The tritium confinement strategy of the ITER design was compared with the safety requirements and thesafety standards and guidelines (ISO 17873) related to nonreactor nuclear facilities to find possible criticalissues in the design of tritium confinement [A3.37]. According to ISO 17873 the tritium plant has only twoconfinement barriers, whilst the actual safety reports on the ITER tritium buildings claim that three lines ofdefence are available. According to ISO standards the process equipment and related containment

[A3.32] M. Frisoni et al., ANITA 2000 activation code package calculation in support of the ENEA Direct 1-Step D1S method, ENEA InternalReport FUS-TN-SA-SE-R-150 (2006)

[A3.33] G. Cambi, D.G. Cepraga and M. Frisoni, Summary results of 2005 activation calculation in support of ITER, ENEA Internal Report FUS-TN-SA-SE-R-135 (2006)

[A3.34] M.T. Porfiri, S. Paci and N. Forgione, Experimental campaign 2005 for the dust removal in the STARDUST facility, ENEA Internal ReportFUS-TN-SA-SE-R-145 (2006)

[A3.35] M.T. Porfiri et al., Feasibility study for a torus shape facility aimed at dust mobilization and removal experiments, ENEA Internal reportFUS-TN-SA-SE-R-158 (2006)

[A3.36] A. Natalizio, L. Di Pace and T. Pinna, Post-accident recovery: a worker dose perspective, ENEA Internal Report FUS-TN SA-SE-R-149(2006)

[A3.37] C. Rizzello and L. Di Pace, Tritium building and detritiation systems. Considerations on tritium confinement, ENEA Internal Report FUS-TN-SA-SE-R-148 (2006) R

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Fig. A3.28 – View of the upper part of STARDUST-U

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enclosure form the first containment barrier, while according to ITER the process equipmentconstitutes the first barrier and, in the specific case, glove boxes are part of the second barrier. Theventilation flow rates chosen appear too low compared to ISO Standards and also to other relatedguidelines (e.g., US Department of Energy standards).

An alternate concept of the ITER atmosphere detritiation has been proposed to mitigate accidentaltritium releases [A3.38]: a scrubber capable of contacting with a spray of water all the air effluentfrom the areas where the tritium systems are located. If a tritium spill occurs in the room atmosphere,the stream of scrubbing water will dilute the concentration of HTO in the effluent, thus reducing therelated environmental impact. A critical analysis of this unit is however required to demonstrate thecapability of such a concept to cope with the ITER safety requirements.

Collection and assessment of data related to JET occupational radiationexposure

The scope of the work [A3.39] was to update the database of JET ORE experience up to the endof 2005. The collective worker doses are the highest during the machine shutdown state, but aredue primarily to in-vessel work. The monthly collective worker doses accrued from ex-vessel workduring the shutdown state are comparable to those accrued during the non-shutdown state. Themaintenance group collective doses are the highest during the machine shutdown state, but are dueprimarily to in-vessel work. The maintenance group monthly collective doses accrued from ex-vesselwork during the shutdown state are comparable to those accrued during the non-shutdown state.The majority of the collective doses from ex-vessel work, with the machine in the shutdown or non-shutdown state, is accrued by non-maintenance workers. Finally, there is no significant differencefor ex-vessel exposure time between the shutdown and non-shutdown state. The same is true forwork effort. It is possible to conclude that most of these results could be generally applicable toITER. In fact the ITER doses accrued during the non-shutdown state could be expected to be asignificant fraction of the total dose, as they are at the JET facility.

JET data collection on malfunctions and failures of ICRH system components

The data from operating experience of JET for the ion cyclotron resonance heating (ICRH) systemwere gathered for the data collection on failures of components used in fusion facilities [A3.40].Alarms/failures and malfunctions occurred during operations from March 1996 to November 2005.Data related to crowbar events were also collected. About 3400 events classified as alarms orfailures related to specific components or sub-systems were identified. The ICRH was operatedduring about 12000 plasma pulses from March 1996 to November 2005. Failure probabilities ondemand were evaluated with regard to the number of pulses operated. The highest number ofalarms/failures (1243) are related to erratic/no-output of the instrumentation and control (I&C)apparatus. Tetrode circuits failed 829 times, the high-voltage power supply system 466 times andthe tuning elements 428 times. The maximum number of events related to I&C (595) led toanomalous operations of CODAS, followed by 125 anomalous operations of stubs. The number offailures/alarms of the ICRH system increases quite linearly with the number of pulses in which thesystem is operated. A crowbar event happened on average every nine ICRH pulses. The rate offailure on demand of an ICRH module is about 0.29/pulse.

JET dust in-vitro experiment: result assessment and in-vivo experimentliterature review

The work dealt with the analysis of in-vivo experiments and dosimetry models on the inhalation oftritiated dust [A3.41]. The most consistent in-vivo experimental activity on the inhalation of metaltritides was performed at the Lovelace Respiratory Research Institute (Albuquerque, NM, USA),using Ti, Hf and Zr tritides with different size distributions. The aim of these experiments was to setup a biokinetic and dosimetry model to better describe inhalation of T particles in a living being, and




to derive suitable dose conversion factors. Analysis of the experimental results confirmed the concernsabout the inadequacy of the protection guidelines for workers exposed to tritium in particulate form (dusts,flakes), if based on the radiotoxicity of tritium. The behaviour of tritiated dust in the human body is still notwell understood, considering the different size distributions and the variety of base materials (throughdensity and morphology). The in-vivo and in-vitro studies on tritiated dust have shown the dependence ofthe tritium clearance and retention in the human body on their physico-chemical parameters. Tritiumabsorption in the lungs from tritiated dust ranges from absorption type S (slow) to type M (moderate)according to the International Commission on Radiological Protection (ICRP) classification, whereas HTOand HT are classified as F (fast).

Study on recycling of fusion activated material

The study was devoted to the Power Plant Conceptual Study (PPCS) Model AB, based on the HCLLbreeder blanket concept using EUROFER as structural material and Pb-17Li as breeder material, neutronmultiplier and tritium carrier [A3.42]. For each main component the categorisation for two decay times (50and 100 years) has been provided according to the following classification:

• Clearable, with clearance index CI < 1 (CI from IAEA-TECDOC-855).

• Specific activity <1000 Bq/g (suggested as operative value for recycling in foundries).

• Dose rate < 2 mSv/h (shielded handling material, termed as “SH”).

• Dose rate ≥ 2 mSv/h, (recycling, if feasible, would require remote handling, termed as “> SH”).

Comparing the categorisation results, given in terms of mass or volumes, there is a large increase in thefraction that could be cleared and recycled without major complications, allowing 100 years of decay.Passing from 50 to 100 years, there is a large transfer of material (~60% of the total mass) from class“>SH” to class “SH”. This suggests that it would be convenient to extend the decay period up to 100years. Furthermore, the extra decay period up to 100 years could be limited to SH and >SH categories,as the overall inventory of clearable plus material with specific activity <1000Bq/g does not change.

For the lifetime components (toroidal field coils, vacuum vessel and low-temperature shield), the related mass share after 50 or 100 years ofdecay is reported in table A3.IV.

At 100 years’ decay time, the SH recycling should be feasible for about76% of the mass of replaceable components. LiPb reuse may reducethe total amount of activated material by about 23% in mass, with acorresponding reduction in the >SH inventory of 65% in mass at 100years of decay. Considering all the activated materials generated fromdecommissioning and from operation, a conservative approach for theirmanagement, based on clearance/recycling of lifetime components only,would lead to 29% mass cleared/recycled and the rest (71%) disposed of. If one takes into account thescenario with LiPb reuse, and an effective recycling capability of ~50% of >SH and SH categories, thecleared/recycled mass fraction would be ~69%, while the remainder should be disposed of.

[A3.38] C. Rizzello and L. Di Pace, Proposal of an atmosphere detritiation system for the ITER plant, ENEA Internal Report FUS-TN-SA-SE-R-151 (2006)

[A3.39] A. Natalizio and M.T. Porfiri, JET radiation exposure analysis. Data relating to the years 1988-2005, ENEA Internal Report FUS-TN-SA-SE-R-157 (2006)

[A3.40] G. Cambi and T. Pinna, JET data collection on component malfunctions and failures of ion cyclotron resonant heating ICRH system,ENEA Internal Report FUS-TN SA-SE-R-143 (2006)

[A3.41] L. Di Pace, Literature study on in vivo experiments with tritiated dust, ENEA Internal Report FUS-TN-SA-SE-R-144 (2006)

[A3.42] L. Di Pace, Definition of components and materials involved in clearance and recycling for PPCS plant model AB, ENEA Internal ReportFUS-TN-SA-SE-R-153, TW5-TSW-001/ENEA/D1 (Rev. 1) (2006) R

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Material Decay time Decay timecategory (=50 years) (=100 years)

Clearable 43.0% 66.4%

< 1000 Bq/g 32.8% 9.4%

SH 5.0% 24.2%

>SH 19.2% 0.0%

Table A3.IV – Percentage of materialsto be dispersed after 50 and 100 years

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A4.2 ITER and ITER-Related Activities

ITER toroidal field cable conductor

ENEA is a member of the international testing group for the ITER magnet R&D. At the end of 2005the measurement campaigns started on the samples (toroidal field advanced strands [TFAS] 1and 2), the first ITER-type full-size TF conductors, made with the recently developed “advanced”Nb3Sn strands [A4.1, A4.2].

ENEA actively contributed to the definition of the testing programme for the conductors, attended

A4 Superconductivity


In 2006 activities were focussed basically on the ITER project and related tasks, as well as on some

important non-ITER tasks. In particular, work began on an important goal of the ITER parallel programme,

the so-called Broader Approach (BA), consisting of the design and construction of the NbTi toroidal field

coils of the new Japanese tokamak JT-60SA. Due to the complexity of the subject, the work is carried out

in close collaboration with other ENEA groups, and within an international framework including the French

and, of course, Japanese teams.

In the framework of an EFDA assignment, ENEA has been charged with following the construction of the

new European dipole conductor, a new test facility for ITER full-size samples. In this framework, the group

developed and patented a new type of joint between superconductive cables. ENEA is also in charge of

surveying the manufacturing of the new conductor samples for the toroidal field coils of ITER.

The activity related to high-temperature superconductors (HTSs) can be summarised as follows: 1) Metallic

textured substrate for YBe2Cu3O7-x-coated conductors: texture and micro-structural evolution and control

of in Ni-5at.% W alloy and development of copper-based substrates, carried out in collaboration with the

Technical University of Cluj-Napoca (TUCN) Romania. 2) Chemical approach for YBCO film deposition by

the MOD-TFA technique and introduction of artificial pinning centres in YBCO films for critical current

improvement (in collaboration with TUCN and Roma Tre University). 3) Activities carried out in the framework

of the Frascati Laboratory of the National Institute of Physics (LNF-INFN) superconducting magnet

programs: i) magnetic characterisation of NbTi and Nb3Sn wires for the development of fast ramped

superconducting dipoles for the FAIR accelerators at Gesellschaft fu..r Schwerionenforschung (GSI)

Darmstadt Germany, NTA_DISCORAP programme; ii) application of MgB2 wires and tapes, MARIMBO

experiment. 4) Transport and thermal stability characterisation of commercially available HTS wires and

tapes, funded by the EFDA Technology Work Programme HTSPER task, carried out with the support of the

SuperMat National Research Council (CNR)-INFM Regional Laboratory facilities at Salerno Italy.

All these activities are leading ENEA toward deeper knowledge of superconducting-based magnet

technology.

62


the tests, which continued through the first half of 2006, and participated in the data analysis andprocessing, in collaboration with the international testing group members.

In spite of the high-performance strands used in the cabling, the TFAS samples showed very unusualbehaviour, with very wide transitions and well before the expected current sharing temperature values.Based on these results, EFDA promoted the fabrication of different toroidal field conductor prototypes(TFPRO project) for testing the effect of mechanical stress on the Nb3Sn superconducting characteristics.A total of four different cables was produced in 2006.

ENEA was assigned the task to supervise the Luvata (formerly OuktoKumpu) activities for conductormanufacturing, under two different contracts (tasks TMSC-TFPRO-1298 and TMSC-LPTCON-1525).signed with EFDA.

For the TFPRO task, two conductors were made with a bronze route Nb3Sn strand produced by EASGermany, while for the LPTCON task a second couple used a strand produced by Oxford InstrumentsSuperconducting Technologies (OST, England) with internal-tin technology (fig. A4.1).

Differently from the previous TF geometry, the four samples have mainly the same cable layout, based ona starting triplet formed of two superconducting strands and one copper strand, but differing slightly intwist pitch length and final cable diameter (i.e., different void fraction). This choice was made in order totest the conductors under different mechanical stress conditions, to which the single strand is subjectedto at operating conditions. The four conductor samples were shipped to the Association Euratom-SwissConfederation Villigen [CRPP]) in November 2006 and are under test.

ENEA is also working on developing the functional dependence of cable stiffness as a function ofmanufacturing parameters for the TF, through the use of computer codes based on finite elements models(FEMs) and artificial neural networks (task TMSC-CABLST).

[A4.1] P. Bruzzone et al., Test results of two ITER TF conductor short samples using high current density Nb3Sn strands, presented at theApplied Superconductivity Conference - ASC (Seattle 2006)

[A4.2] R. Zanino et al., IEEE Trans. Appl. Supercond. 16-2, 886 (2006) Ref

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Fig. A4.1 – Cross section of the four cables ready for characterisation

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Current redistribution study on ITER conductors

Cable-in-conduit conductor (CICC) performance is affected by the current distribution among thestrands. To better understand this phenomenon and its implications, the results from theexperimental data taken on the NbTi BB-III sample, tested in the TOSKA facility at FZK, and on thepoloidal field insert sample tested in SULTAN (CRPP) in 2004 are being studied in collaboration withthe University of Udine [A4.3].

It has been shown that, during Tcs measurements, a current re-distribution among the cable sub-stage bundles appears just before the conductor transition, i.e., well before any detectable voltagedevelopment. Such a phenomenon, repeatable and depending on the overall transport current, hasbeen observed by Hall probe sets designed with ad-hoc sensitivity and geometry, to allow also thereconstruction of the current distribution inside the CICC by means of the THELMA code.

EFDA dipole

As is well known, to reach the high field values requested for ITER operation, Nb3Snsuperconducting cables have to be used to wind the main magnets, the central solenoid and thetoroidal field coils. A fundamental step in the design and construction of these ITER magnets is totest a lot of conductor samples in relevant operating conditions. The only facility available at themoment in Europe for this purpose is SULTAN, which will not be able to withstand the huge dutyforeseen for ITER construction in the very near future. Thus the European Community decided tobuild a new facility to share the test tasks with SULTAN.

The facility will be based on a wind and react (W&R) dipole magnet wound from the last generationof Nb3Sn strands, the so-called “advanced strands”, and it will be the very first magnet based onsuch strands, and also the first dipole ever made by using CICC. ENEA has been charged withsupplying the cable and following the manufacture of the entire amount of CICC for the dipole (taskTMSC-DIPCON-1316). A few meters of a prototype conductor were manufactured and testedsuccessfully in SULTAN in 2005. Unlike what was obtained in the first ITER TF full-size samplesmade using the same kind of strands (TFAS samples), the performance of the conductors agreesvery well with expectations.

The activity in 2006 was carried out in close collaboration with EFDA and Luvata. During this periodthe cable parameters were drawn, and a short dummy cable, made only of copper strands, wasproduced in order to define the cabling process and allow Luvata to prepare the environment andbuild the tools. The dummy consists of a short (50 m) copper cable, processed according to theactual cable parameters, jacketed and compacted to the final dimensions. It was decided togetherwith EFDA to use a square cross section for this dummy cable, instead of the rectangular one usedin 2005.

A whole set of jacketed superconducting cables has been produced so far: two high-field units andfour low-field units, for a total length of about 600 m. Of the six cable lengths, the low-field units arestill uncompacted, while the two high-field units were compacted to the final dimensions anddelivered to BNG Industries Germany for further assembling tests.

Short lengths of each sample were prepared and sent to CRPP for characterisation. The resultsobtained so far for square conductors are not encouraging, probably due to the different voidfraction and pressure on single strands during operation, so new rectangular cable samples are inpreparation (fig. A4.2), and additional tests are foreseen (task PITCON).

In the framework of the dipole design and construction, EFDA asked ENEA to develop a new typeof joint between CICCs. ENEA developed a new joint concept and designed and fabricated someprototypes, whose test results showed a very low electrical resistance (< 1nΩ). The mainadvantages of this new joint (ENEA patent) are the low room occupancy (only slightly higher thanthe conductor size itself), the easy manufacturing procedure, and the low cost of realisation. The




ENEA joint was accepted by EFDA and used as the only type ofjoint between all the different lengths of the dipole magnet.

Accompanying activities included providing mechanical analysesthat will support the engineering design and manufacturing phase ofthe dipole procurement (contract TMS-EDDES4–1303, completedin 2006). The cable jacket main deformation occurring during the compaction and winding phase, the peakstress in the insulation, due to the large pressure excursion occurring during the magnet quench inside theconduit, and the thermo-mechanical analysis of dipole assembly during the cool-down phase were allevaluated. An experimental benchmark at the bending FEM analysis was also carried out. In the last part of2006 ENEA undertook (contract TMSC-DICOMO-1480) to develop a code model that could help to investigatethe sensitivity of Nb3Sn superconducting properties to mechanical strain, which causes significant problems inthe accurate performance prediction of large multi-strand CICC. Empirical relationships between strain andcritical current have already been established, based on experimental measurements with known applied strainfields. The problems arise in the prediction of the strands stress/strain state within a cable. A large CICCincludes hundreds of strands twisted with different pitches and in contact with each other and with the externaljacket. Moreover, individual strands exhibit non-linear average mechanical behaviour due to the plasticity of theconstituting components. At this point, the definition of a suitable numerical model for the mechanical analysisof strands in cables is still an open problem. Simplified methodologies should be developed with the aim ofpredicting the mechanical behaviour of cables and strands. The present activity deals with evaluating the strainstate of the strands in the dipole CICC during energization within a magnetic field.

In addition, EFDA charged ENEA with performing code simulations of the mechanical stress arising in thedipole structure during cool down and in operating conditions. This work was successfully carried out, withthe help of L.T. Calcoli personnel, during the first half of 2006.

Barrel bending experiments

The EFDA task named “barrel bending experiments” (BARBEN) was completed during the first months of2006. Its aim was to study the effect of a bending strain applied on relatively long lengths of Nb3Sn“advanced strands”, initially inserted and compacted in stainless tubes before heat treatment.

The effect of a 0.5% peak bending strain on the performance of an internal tin strand developed by OSTfor ITER was investigated. Comparison between the measured critical current data of the unbent samplesand the results computed by Durham’s scaling law showed that, for the analysed system, the differentialthermal contraction of stainless steel and superconducting strand corresponds to a –0.57%pre–compression of Nb3Sn at 4.2 K. At 12 T the strand shows a performance decrease of about 10-20%with the application of a 0.5% peak bending strain [A4.4].

A further activity outside the EFDA task itself concerned clarifying the influence of the twist pitch length onthe strand performance degradation, when submitted to bending strain. Hence similar experiments wereperformed on Nb3Sn strands in which the superconducting filaments were not twisted.

Optimisation of NbTi strand for PF1/PF6 performance

The original strand specification for the high-field ITER PF coils (P1/P6) was based on the LHC strand andwas 2900A/mm2 at 5 T and 4.2 K. Using the recommended scaling formula, this gave an acceptablepredicted critical current density at the P1/P6 critical conditions.

[A4.3] F. Bellina et al., IEEE Trans. Appl. Supercond. 16-2, 1798 (2006)

[A4.4] L. Muzzi et al., Pure bending strain experiments on jacketed Nb3Sn strands for ITER, presented at the Applied SuperconductivityConference - ASC (Seattle 2006) R

efer

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Fig. A4.2 – A short piece of the rectangular Nb3Sn

CICC for dipole application

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However, it seems that NbTi strands have been optimised for low-temperature performance at theexpense of the Jc at higher temperatures. The scaling formula is essentially an envelope of themaximum achieved current density at each field/temperature and appears to be un-representativeof these LHC strands at 6 T and 6.5 K. The difference in Jc (measured vs predicted) is substantialand only some of the variation may be due to measurement errors, as small errors at temperaturesabove 6 K produce a large change in critical current.

At the end of 2006, ENEA was charged with developing and producing at least 50 kg of Ni-platedNbTi strand according to the ITER P1/P6 strand specification, with optimised current carryingcapabilities at higher temperatures and fields (TW6-TMSC-NbTi). The minimum required non-Cu Jcat 6.5 K and 6 T is 200A/mm2. The optimisation processes for NbTi are quite well understood andthe performance at 6.5 K and 6 T can be improved by changing the process parameters duringproduction, e.g., adjustments to the intermediate annealing steps. The activity will be carried outduring 2007.

A4.3 JT-60SA

The Broader Approach is a project related to the ITER Accompanying Programme and involvescooperation between Japan and the EU for the construction of a new tokamak machine in Japan,JT-60SA. In Europe, CEA and ENEA have been assigned the specific tasks to design, construct and

test the 18 toroidal plasma confinementmagnets (fig. A4.3) made of NbTi strands. ENEAis in charge of coordinating all the related EUactivities and consequently has been involved inthe conductor and coil design

In 2006, a preliminary assessment of the toroidalmagnet characteristics in regard to theexpected operative conditions was carried out.ENEA is working on a consistent conceptualdesign concerning the strand choice as well asthe conductor and coil layout definition. At themoment, the definition of toroidal-coil design isstill being discussed among the members of thejoint project. Related to this activity, the ENEAFrascati facility for testing and characterisingsuperconducting strands at variabletemperatures (4.2 K – 20 K) and magnetic fields(up to 12 T) has been considerably upgraded in

terms of accuracy, repeatability and signal-to-noise ratio, becoming one of the most reliable andversatile among the few available in Europe for this kind of characterisation. It has allowed anextended campaign of NbTi strand characterisation, focussed on the foreseen operative conditionsof JT-60SA.

A4.4 High–Temperature Superconducting Materials

Evolution and control of cube texture in Ni-W substrates for YBCO-coatedconductors

The realisation of high critical current density YBe2Cu3O7-x-based coated conductors with therolling-assisted biaxially textured substrate (RABiTS) approach is primarily related to the sharpness



200400

600600

400

400

400

Fig. A4.3 – Magnetic system of the Japanese tokamak

JT60SA: in red the 18 toroidal coils to be designed,

built and tested in the EU


of cube texture developed in the substrate.Among the various Ni–based tapes proposed,Ni-W alloys have attracted particular interestbecause of the enhanced mechanicalproperties and reduced magnetism withrespect to pure Ni, and the sharp and almostpure cube texture that can be obtained afterrecrystallization of cold rolled tapes.

The texture of highly (>90%) deformed fccmetals with a medium-high stacking fault energy (SFE) is concentrated in the so-called β-fibre, known asthe stable end position of lattice rotations occurring during cold rolling. The development of cube texturethrough recrystallization is directly related to the deformation texture, as the stronger the β-fibre the sharperthe cube texture in the (111) pole figure. During annealing, the deformation texture evolves into the cubetexture. Annealing up to 600°C does not affect the deformation texture in Ni 5 at% W (Ni–W) tapes, as noorientation difference with respect to the as-rolled samples can be detected (fig. A4.4).

Conversely, at 700°C a structural modification appears, with the coexistence of cube and deformationtextures, since four symmetric poles, at tilt angle χ=54.7° and azimuthal angles ϕ=45°, 135°, 225° and315°, are superimposed on the pre-existent texture in the (111) pole figures. Finally, for temperatures higherthan 800°C the sample is cube oriented and no residual deformation texture is detectable; the onlyidentifiable poles other than cube are due to {221}<122>, namely cube twins, which are intrinsically relatedto the recrystallization of cube grains. However, indications of microstructural modifications already at600°C are revealed by a Monte Carlo procedure onθ–2θ x-ray diffraction peaks, since an evaluation of themicrostrain contribution to peak broadening is provided.No remarkable modification is produced up to 500°C,while above this temperature a decrease in microstrainis evident, indicating a relaxing of the lattice defects bythe decrease in the dislocation density, i.e., the materialunderwent the recovery phase (fig. A4.5). In fact, duringthis stage, part of the energy stored during deformationis released through dislocation rearrangement/annihilation and subgrain formation, leading tomodification of several physical properties, such ashardness and electrical conductivity, without affectinglattice orientation. Further microstrain reduction above700°C is due to the growth of strain-free orientedgrains, namely recrystallization, which is completeabove 800°C.

After complete recrystallization the tapes may exhibit, to the naked eye, a more or less opalescent surface.This feature is the result of the diffusion of light coming from pronounced grain boundaries, which arenormally high-angle boundaries, i.e., with a relative misorientation greater than about 15°. This is the caseof cube twins, often arranged in longitudinal bands. It was shown that the formation of components otherthan cubes is related to the grain size of the bulk material before cold rolling (initial GS) (fig. A4.6). Inparticular, the area of cube orientation decreases because of the increase both in cube twins and in non-cube orientation as the initial GS becomes larger. These data indicate that twin formation is related to boththe SFE and the deformed state (fig. A4.7, A4.8). The resulting direct relation between cube twins andnon-cube area densities suggests that their formation is controlled by a common parameter. Thiscorrelation is supported by data from several samples of Ni-V, Ni-Cr and Ni-W. In particular, large non-cubegrain fractions correspond to samples subjected to a deformation degree below 95%, in which the fewcube grains were almost invariably twinned.

Both in- and out-of-plane distributions of the cube orientation measured by x ray are in agreement withelectron backscattering diffraction (EBSD) analysis in terms of cube texture coarsening, as an increase in

67

a) 600°C b) 700°C c) 800°C

Mic

rost

rain

Annealing temperature (°C)

Vic

kers

har

dnes

s H

V20

04×10-3

3×10-3

2×10-3

1×10-3

200

100

300

400

0 200 400 600 800 1000

Fig. A4.4 – (111) pole figures for three Ni-W samples annealed at

a) 600, b) 700 and c) 800°C and quenched to room temperature

Fig. A4.5 – Evolution of microstrain and Vickers

hardness for Ni-W samples annealed at different

temperatures and quenched to room temperature

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the spread around the {001}<100> ideal orientation forlarger initial GS is observed. As a consequence of thisbehaviour, a broader distribution of the cube texture isobserved in substrates with reduced cube area fraction.This kind of relationship seems to be a general featuresince it has been observed in several Ni-based substrates.This result is of great conceptual and practical importancebecause hindering cube twin formation not only provideslarger cube areas, but leads to sharper cube textures aswell [A4.5].

Nickel-copper alloys as textured substratesfor YBCO–coated conductors

Ni-Cu-Co alloy tapes with different relative concentrationswere studied as textured substrates for YBCO-coatedconductor application. A small amount of cobalt was

added in order to enhance the oxidation resistance of Ni-Cu alloy. 100-μm-thick tapes wereobtained through conventional cold rolling to a deformation degree of 97% followed by recrystalliza -tion at high temperature. The use of different thermal treatments made it possible to obtain areadensities of cube orientation as high as 95% (figs. A4.9, A4.10). The substrate was thoroughlycharacterised by means of x-ray diffraction, EBSD and scanning electron microscopy (SEM)analyses. Electrical resistivity, mechanical properties and oxidation resistance of this substrate willbe compared with those exhibited by Ni, Ni-W and Ni-Cu tapes.

A Pd transient layer was epitaxially grown prior to depositingconventional CeO2/YSZ/CeO2 buffer layer architecture inorder to passivate the Ni-Cu-Co substrate. The depositionconditions for the Pd layer were optimised in order to obtaina particularly sharp out-of-plane orientation, so that the fullwidth at half maximum (FWHM) of the rocking curves in thetransverse direction (TD) through the (002) reflection drops



Are

a fr

actio

n (%

)

Initial grain size (μm)

6

4

2

010 30 50 70

cube twinnon–cube

FW

HM

(de

gree

)

Initial grain size (μm)

9

7

510 30 50 70

Δω(RD)Δω(TD)Δφ

Fig. A4.7 – Non-cube and cube twin area density

drawn from EBSD measurements for Ni-W

samples with different initial GS

Fig. A4.8 – FWHM of (200) rocking curves, along

both rolling (empty triangles) and transverse

directions (full triangles), and of (111) φ-scans

(empty circles) for Ni-W samples with different

initial GS

RD

TDFig. A4.9 – EBSD map for a recrystallized Ni-Cu-Co alloy substrate.

Red, green and blue colours refer to {100}, {110} and {111} planes

100 μm

0 10 20 30 40 50 60Deviation from {001} <100> (°)

100 μm

0 10 20 30 40 50 60Deviation from {001}<100> (°)

a) b)

Fig. A4.6 – EBSD misorientation maps for Ni-W samples with initial GS of

19 µm a) and 63 µm b)


from about 9° of Ni-Cu-Co to 2.1° of Pdlayer; whereas in the rolling direction (RD)these values attain about 6 and 1.7°,respectively. This sharp texture is preservedand both CeO2 and YSZ films exhibit thesame out-of plane orientation (fig. A4.11).

The encouraging structural properties of thebuffer layer architecture obtained indicatethat this alloy is a promising alternativesubstrate for the realisation ofYBCO–coated conductors.

MOD-TFA YBCO films

It has been demonstrated that metal-organic deposition (MOD) using trifluoroacetate (TFA) precursors isthe most suitable for epitaxial YBCO deposition. In the MOD-TFA method, a fluorine containing coatingsolution decomposes to fluorides which, in turn, undergo different chemical reactions during the high-temperature firing process (700 – 800°C) in controlled atmosphere to convert to oxides.

The precursor solutions for YBCO were prepared by sonicating the mixture of Y, Ba and Cu acetates in a1:2:3 cation ratio with a stoichiometric quantity of trifluoroacetic acid in de-ionized water. The resultingsolution was slowly dried at low temperature to form a glassy blue resin. The precursor solution wasdeposited both on (00l)-oriented SrTiO3 single crystals and on Ni-W/Pd/CeO2/YSZ/CeO2 templates byspin coating. The resulting gel films were treated in two heating stages to obtain the YBCOsuperconducting films. The YBCO films obtained under these conditions are about 250 nm thick.

The x-ray diffraction (XRD) pattern of θ–2θ scans for YBCO/CeO2/YSZ/CeO2/Pd/Ni-W exhibits only the(00l) YBCO peaks. No (h00) reflections due to a-axis oriented grains were observed. The presence of the(111) reflection of YSZ and CeO2 indicates a small fraction of (111) oriented grains in these films. The (002)to (111) peak intensity ratio is of about 102. The rocking curve through the (002)Ni-W, (002)YSZ, (002)CeO2and (005)YBCO peaks have an out-of-plane FWHM of 8.8°, 4.2°, 3.8° and 3.4°, respectively. The smallvalues of FWHM for the YSZ and CeO2 with respect to the Ni-W substrate is correlated to the Pd film. Thein-plane crystallographic relationship of the structure is [100]YBCO||[110]CeO2 ||[110]YSZ||[100]Ni-W.

The surface of YBCO/CeO2/YSZ/CeO2/Pd/Ni-W films is free of cracks but has some holes. In spite of thevoids, the c-axis oriented grains are well connected. Furthermore, YBCO grains are connected over pores.

[A4.5] A. Vannozzi et al., Supercond. Sci. Technol. 19, 1240-1245 (2006) Ref

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TD NiCuCo-Pd 1TD NiCuCo-Pd 2RD NiCuCo-Pd 1RD NiCuCo-Pd 2

θ (degree)10 20 30 352515

7×104

5×104

3×104

1×104

10

Inte

nsity

(arb

. uni

ts)

Fig. A4.11 – Rocking curves around (002) reflection of Pd films grown at

different temperatures on Ni-Cu-Co substrate. A consistent sharpening

of the out-of-plane orientation is attained for higher deposition

temperatures

RD

TD

{1,1,1}32

16

8

4

210.50.13

Fig. A4.10 – (111) pole figure obtained from EBSD

data for a recrystallized Ni-Cu-Co sample

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The spherical particulates arenanocrystallites of CuO(fig. A4.12). The high qualityof the YBCO films isconfirmed by the Tc values(90.9 K) and the reducedtransition widths (ΔT∼1.5 K)(fig. A4.13).

Jc values as high as1 MA/cm2 are reported at84 K, reaching 2.7 MA/cm2

at 77 K for YBCO TFA filmsdeposited on SrTiO3 singlecrystals. The development ofMOD-TFA YBCO films onlong length CeO2/YSZ/CeO2/Pd/Ni-W template is inprogress [A4.6].

Introduction of artificial pinning sites in YBCO films

One of the most effective ways to improve the pinning efficiency of magnetic flux vortices in YBCOfilms is the introduction of epitaxial second–phase nanoinclusions in the YBCO matrix. Thistechnique has gained relevant interest due to the possibility of increasing the irreversibility field (Hirr),which limits high magnetic field performance.

This goal has been pursued by growing YBCO thin films with the pulsed laser deposi tion (PLD)method from com posite targets obtain ed by adding BaZrO3 (BZO) powder in molar percentsranging from 2.5 to 7%. The presence of BZO epitaxial inclusions inside the films has been checkedby XRD analysis (fig. A4.14).

As already reported in the literature, the introduction of second-phase nanoinclusions progressivelylowers the critical temperature Tc of YBCO thin films (fig. A4.15).

Analysis of the transport properties shows the improvement of pinning efficiency in YBCO films withBZO inclusions. Self-field critical current densities are increased by BZO addition, ranging from 1.23MA/cm2 for pure YBCO film to 2.22 MA/cm2 recorded for 2.5 mol.% BZO-YBCO film. All the BZOadded films exhibit increased critical current densities in the whole magnetic field range inspectedand higher irreversibility field values, with the 5 mol.% BZO-YBCO film the best in field performances(fig. A4.16a)). The improvement in the transport properties in BZO samples can be ascribed to theintroduction of extended defects elongated along the YBCO c-axis, as shown by a prominent peak



Res

ista

nce

(Ω)

Temperature (K)

20

10

00 100 200 300

8

6

4

2

080 90 100

TC=90.9 K

100 nm

Fig. A4.12 – Film surface of YBCO TFA grown on

CeO2/YSZ/CeO2/Pd/Ni-W

Fig. A4.13 – R(T) plot for YBCO TFA grown on

CeO2/YSZ/CeO2/Pd/Ni-W

Inte

nsity

(co

unts

/s)

2θ (degree)

2.0×105

1.5×105

1.0×105

0.5×105

00 20 40 60 80 100 120

(100

)

(200

)

(400

)

(500

)

(700

)

ST

O (

100)

ST

O (

200)

ST

O (

300)

ST

O (

400)

BZO(100)BZO(200)

BZO(400)

19 20 21 22 23 2440 42 44 46 48

94 95 96 97 98

Fig. A4.14 – X-ray θ-2θ diffraction spectrum showing the presence of

BaZrO3 epitaxial second phase inside the YBCO matrix


at 0° (magnetic field parallel to the c-axis) in the critical currentdensity dependence on the angle between the magnetic fielddirection and the direction normal to the film (fig. A4.16b)).Measurements of the microwave complex resistivity in the mixedstate were carried out for films deposited on SrTiO3 and sapphiresingle crystal substrates. The pinning frequency νp , whichrepresents a measure of the steepness of the potential well for theflux lines, can be estimated from complex resistivity. Very highvalues of about 50 GHz are attained between 60 and 80 K,indicating extremely high vortex pinning and steep potential wells.As expected, the νp rapidly drops to zero as T approaches Tc. It canbe concluded that the intragrain vortex pinning at high microwavefrequencies in YBCO films with BZO inclusion of nanometric sizehas been greatly improved with respect to films free of BZOinclusions.

Magnetic characterisation of superconducting wiresfor fast ramped superconducting dipoles

The INFN Dipoli Super Conduttori Rapidamente Pulsati(DISCORAP) programme originates from the new requirement ofdeveloping fast-ramped superconducting dipoles for the FAIRaccelerators at GSI, Darmstadt, Germany. It is a four-year programto develop a fully working bent dipole 3.8 m long in its horizontalcryostat. The dipole has to generate a field of 4.5 T with a rampingrate of 1 T/s.

Magnetic measurements in high magnetic field were carried out toextract information about the intrinsic magnetization losses, criticalcurrent, and filament size. Dissipation, when the magnetic field israpidly changing, comes from the filament couplings, which areconnected through the metallic matrix. The magnetization M ofNbTi and Nb3Sn wires was analysed with a vibrating samplemagnetometer (VSM) operat ing in the range [300 - 4] K under amaximum field up to 12 T. All the tests were carried out in the zero field cooling (ZFC) situation to be ableto record the purely diamagnetic response at low magnetic field, useful for studying the shielding regimes.Figure A4.17 shows magnetic measurements for a 2-μm filament prototype NbTi wire.

[A4.6] A. Rufoloni et al., J. Phys.: Conf. Ser. 43, 199 (2006) Ref

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Nor

mal

ised

res

ista

nce

Temperature (K)

1.2

0.8

0.4

080 90 10085 95

a)YBCO-STOYBCO-BZO (2.5%)-STOYBCO-BZO (5%)-STOYBCO-BZO (7%)-STO

Crit

ical

tem

pera

ture

(K

)

BaZrO3 nominal concentration (vol.%)

90

88

86

840 2 4 6 8

YBCO-STOYBCO-BZO (2.5%)-STOYBCO-BZO (5%)-STOYBCO-BZO (7%)-STO

b)

Crit

ical

cur

rent

den

sity

(A

/cm

2 )

Magnetic induction (T)

105

103

1010 4 8

YBCO-STOBZO (F2.5%)-STOBZO (F5%)-STOBZO (F7%)-STO

T=77K a)

Fig. A4.15 – Normalised

resistance as a function of the

temperature for YBCO films

with BZO molar concentration

ranging from 2.5 to 7% a).

Dependence of the critical

temperature Tc on the BZO

molar concentration b)

Crit

ical

cur

rent

den

sity

(A

/cm

2 )

Angle (degree)

6×105

4×105

2×105

0-100 -50 0 50 100

YBCO-BZO(F7%)-3 77K

μ0H=100 mT

μ0H=1 T

μ0H=3 T

μ0H=5 T

b)

Fig. A4.16 – a) Critical current density as a

function of the applied magnetic field at T=77K

for YBCO films with BZO content ranging from

2.5 to 7 mol.%. b) Dependence of the critical

current density on the angle between the

magnetic field direction and the direction normal

to the film at T=77K recorded for the 7 mol.%

BZO-YBCO sample

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MARIMBO experiment:application of MgB2

Activities regarding MgB2superconductors have beendevoted to fundamentalaspects, such as the influence ofthe disorder introduced byneutron irradiation onpolycrystalline MgB2 materialand the MgB2 phase nucleationby means of MgB2/Mg multi-

layers, and to more applicative features such asthe stability properties of a MgB2 multi-filamentary tape.

The magnetic properties of polycrystalline MgB2exposed to different neutron fluencies wereanalysed to perform in-depth analysis of thecritical field and current density behaviour and toidentify what scattering and pinning mechanismscome into play (fig. A4.18).

In the second study the chemical compositionand electronic structure of the multi-layer filmswere analysed and compared with thecorresponding MgB2 bulk case to investigate thereasons for the low transition temperature typicalof low-temperature processed MgB2 films. Short

straight samples of the Cu-stabilised, 14-filament MgB2 tape, taken from a 1.6–km-lengthproduction manufactured by Columbus Superconductors, Genoa, were used to produce a cryogen-free, double pancake style, magnet. The conductor is a 3.6-mm-wide and 0.65-mm-thick tape,fabricated with the powder-in-tube (PIT) method. The tape is composed of a copper inner regiondelimited by an iron sheath and a nitrogen Niouter matrix where MgB2 filaments are embedded. Thesuperconducting fraction is less than 10% of the whole section. The tape edges were welded over3 cm on the bulk copper sample holder used for the tests, which were performed in a He gas flowcryostat. Two brass counter flow cooled current leads, designed for 200 A, were used to bias thetape. The wire was shielded by thick polystyrene from direct exposure to the cold gas. A 3-mm-wideheater, made of NiCr wire, was wound and glued in the middle of the tape. Voltage contacts atknown positions were used to determine the presence of dissipative regimes. A calibrated cernoxthermometer was located on the tape, a few mm from the heater side. Figure A4.19a) reports theheat propagation velocity νp as a function of the delivered energy E at two temperatures and biascurrents, while figure A4.19b) reports νp as a function of the temperature at two values of biascurrent, each one triggered by a constant energy pulse.

The νp -vs.-energy curve indicates a fast increase in νp at low heater energy followed by a weakdependence for higher energy values. This νp (E) behaviour at low E values may be ascribed to the



Mag

netic

mom

ent (

emu) 0

-0.0005

-0.001

-0.0015

-0.002

T(K) B(T)-6 -4 -2 0 2 4 64 8 12 16

transverse fieldparallel field

transversefield 4.5 K

SL8979Ssample A-I=5.57 mm

50

0

-50

Fig. A4.17 – Magnetic moment for low filament size NbTi wire (2006)

J c(A

/cm

2 )

J c(A/c

m2 )

μoH(Tesla)

105

104

105

104

3 6 9

0 1017 1018 1019

Fluence (cm2)

J0@T=5 K, B=4 T

T= 5 K

P5

P6P0

P2

P4

P1P3

P3.7P3.5

Fig. A4.18 – Critical currents measured in samples

after different neutron doses (P)

Vp(

mm

/s)

100

60

20

Heater energy (J) Temperature (K)

150

90

300 1 20.5 1.5 2.5 15 2520 30

a) b)

μ0H=0 Tμ0H=0 T

20K 200A30K 100A

200A 2.25J150A 0.56J

Fig. A4.19 – Normal zone

propagation velocity as a

function of a) heater energy and

b) temperature


short distance between voltage taps and heater, where the equilibrium balance between the heat loss byconduction and the generated heat is not yet achieved. The νp increases with the temperature becausedissipation increases, narrowing the temperature margin Tg-T0, where T0 and Tg are the operating thegeneration temperature, respectively.

Transport and thermal stability characterisation of HTS wires and tapes: analysis ofquench propagation on YBCO-coated conductors

A 45-cm–long AMSC 344 conductor samplewas used, with a Ni-Cr resistive wire wound inthe middle of the tape as heat source. Thequench propagation was monitored by 12voltage taps distributed along the samplelength. Figure A4.20 reports details of theelectrical connections on the tape. Thedistance between voltage taps is 1 cm and thetotal active length (distance between V+ and V)is 32 cm. The Ni–Cr heater is in the regiondelimited by ch0 voltage taps. Figure A4.21shows a typical result for a set ofmeasurements with increasing energy atT=80 K and Ibias=35 A. Only ch0 and ch1values are plotted for clarity. The energy wasvaried by increasing the current, but keepingthe pulse duration at 0.1 s. Up to 0.36 J a sharpincrease in the ch0 voltage was revealed incorrespondence to the current pulse (t=0 s) andthen recovered after a few seconds. No othersignificant variations in the voltage readingswere observed. For higher energy, propagationsets up as revealed by the increase of the ch1voltage. As expected, the process becomes faster as the energy increases. Heat propagation is stoppedwhen the Ibias is switched off (sharp drops of both ch0 and ch1 marked by arrows in fig. A4.21).

Heat-generation experiments were carried out at 75 and 80 K for different values of Ibias. The heatpropagation velocity evaluated from ch1 as a function of the energy for both 75 and 80 K is reported infigure A4.22a) and b). As can be seen, V1 increases with Ibias. It should be noted that the propagationprocess in this tape is about two orders of magnitude slower than in typical NbTi multifilamentary wire andone slower than in MgB2 tape.

73

5 cm 6 cm 2.6 cm 2.5 cm 6 cm 5 cm | | | | | | | | | | | |

-|--------|---|-------|---|----|---|----|---|-------|---|--------|-

V+ V-ch2 ch1 ch0 ch3 ch4

Fig. A4.20 – Distribution and distance of voltage taps along the

active region of the tapeV

olta

ge (

mV

)

Time (s)

T=80 K; lbias=35A (66% lc)

7×10-3

5×10-3

3×10-3

1×10-3

00 5 10 20 2515

run 21 ch0run 21 ch1run 22 ch0run 22 ch1run 23 ch0run 23 ch1run 24 ch0run 24 ch1run 25 ch0run 25 ch1run 26 ch0run 26 ch1

0.25J0.36J0.42J0.49J0.64J0.81J

lbias off

Sig

nal v

eloc

ity V

1 (m

/s)

Heater energy (J)

2.0×10-2

1.5×10-2

1.0×10-2

0.5×10-2

0

0 0.2 0.4 0.6 0.8 1.21

T=75K

53% lc58% lc64% lc70% lc76% lc82% lc85% lc

a)

Sig

nal v

eloc

ity V

1 (m

/s)

Heater energy (J)

2.0×10-2

1.5×10-2

1.0×10-2

0.5×10-2

0

0 0.2 0.4 0.6 0.8 1.21

T=80K

57%lc66%lc86%lc

b)

Fig. A4.22 – Normal zone propagation velocity in the HTS tape at two different temperatures :a) 75 K and b) 80 K

Fig. A4.21 – Time evolution of voltage along the tape

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The Fast Ion Generation Experiment (FIGEX) proposed and designed by the ENEA Inertial Physicsand Technology Group [A5.1, A5.2] was performed at the Petawatt Facility of the RutherfordAppleton Laboratory (UK) during the first two months of 2006. The aim was to study a possible wayto create by short laser pulses an ion source for inertial fusion energy (IFE) application. The FrascatiABC facility was used to determine the required pre-pulse contrast in the experiment [A5.3]. Analysisof the experimental results was mostly carried out at Frascati ENEA. A large fraction of the activityhad to be devoted to preparing within a few months a software package for the ion spectrometerdata processing. Preliminary results were available for an invited presentation at the EuropeanConference on Laser Interaction with Matter held in Madrid in June 2006.

Since FIGEX was designed for fast–ion generation (MeV/nucleon), a set of Thomson ionspectrometers was used as the key diagnostic. The detectors were plastic CR39 plates where eachion was registered as a pit. Ions on CR39 were registered along parabolas (one for each Z/A, whereZ and A are the ion charge and mass numbers):

(A5.1)

(A5.2)

where (x, z) are the intrinsic coordinates taken with the origin in the point where ions with infiniteenergy would impinge and with the x-axis parallel to the magnetic field H; V and Enucl are the voltageapplied to the plates and the energy per nucleon of the ion registered at the site (x, z). Equation A5.1represents in the plane (x, z) a parabola with the vertex at x=z=0 and the axis parallel to x, whereasA5.2 associates the specific energy to the coordinates (x,z) where the ion impinges.

In analysing the experimental data, to find the intrinsic position of the origin and the direction of theaxes it was sometimes useful to represent the pit positions in the plane Enucl,Z/A) where parabolasbecome straight lines parallel to the Enucl- axis (see an example in fig. A5.1).

A microscope driven by step motors was used to detect the position of the pits imprinted on theCR39. The software associated with the equipment generated information about several features ofeach pit, including their position with respect to a Cartesian coordinate system (u, v). These datawere released as a text file for each CR39 plate.

Rather complex software based on the Mathematica package was worked out and installed on alaptop computer that makes the utility transportable when needed. The software was designed inorder to 1) find the intrinsic coordinate system where eqs. A5.1 and A5.2 hold; 2) recognise the Z/Acorresponding to each parabola; 3) count the number of pits registered on each parabola; and 4)

V

H2

z2

x

�V2

H2(z

x)2

A5 Inertial Fusion



associate to each pit the proper value of intrinsiccoordinates (x,z), the specific energy Enucl and thedistribution function in f(Enucl) pertinent to eachparabola and the associated average energy values,spread in energy, etc.

The code was designed to accomplish tasks 1, 2, 3,4 and to perform ionic distribution functions, globalcalculations relative to the complete set ofspectrometers (6) aligned along different directionsaround the target and to study the angulardistributions for number and energy (fig. A5.2).

This programme was worked out as follows: First ofall the Z/A expected in the experiment (expectedcontaminants included) were evaluated and the corresponding parabolas evaluated by eq. A5.1. Then theintrinsic coordinates were found by superposing (by electronic handling) the experimental parabolas on thetheoretical ones given by eq. A5.1 as in figure A5.3. Figure A5.4 reports an example of species recognitionbased on this method.

[A5.1] A. Caruso and C. Strangio, Laser Part. Beams 19, 295 (2001)

[A5.2] C. Strangio and A. Caruso, Laser Part. Beams 23, 33 (2005)

[A5.3] C. Strangio et al., A study for target modification induced by the prepulse in petawatt-class light-matter interaction experiments,presented at the 28th ECLIM Proceedings (2004) R

efer

ence

s

75

(x, z) plane

(Enucl, Z/A) plane

Fig. A5.1 – Example of ion registration in the intrinsic plane and

in the (Enucl, Z/A) plane

2

1

1.5

0.5

01-0.5-1 0.50

cosθ - view

θ - view

0

θ

cosθ

LARGE

Target surface

Lase

r bea

m

Fig. A5.2 – Example of angular distribution calculations

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To count the pits for each Z/A it was necessaryto isolate the corresponding parabola from theothers and from the background. The codeperformed this task by taking a strip aroundeach parabola having width assigned ad hocas input. The coordinates of the pits in eachparabola were recorded in a file and used toevaluate the associated specific energy Enuclthrough eq. A5.2. From the files the distributionfunction of specific energy for each specieswas evaluated (see an example in fig. A5.5).Once the files pertinent to the number andenergy distribution for each Z/A are known allthe calculations relative to the ion chargedistribution functions are possible, with thelimits determined by the ion species mixing ineach Z/A (fig. A5.6).

A5 Inertial Fusion


Fig. A5.4 – Intrinsic coordinates and ion recognition by

the method of superposing the theoretical curves on the

experimental pattern. Green labels represent missing

elements

Fig. A5.3 – The intrinsic coordinates are found by superposing the theoretical parabolas on the experimental. a) Initial

relative positions of the theoretical and experimental patterns. b) The two patterns have been superposed by electronic

handling and the species are identified

H

O8C6Si14N7 Si13 Si11 Si9

Si12N6

Si10N5

Si8N4Si7C3O4Si6N3

Si4N2

Si2N1

O3

O2

O1

O7 O6 O5C5 C4

Si5

C2

C1

Si3

Si1

a) b)


Analysis of the experiment is expected to be completedwithin the first months of 2007 and part of the resultswill be available for presentation as an invited talk at the7th Symposium on Current Trends in InternationalFusion Research: A Review (5-9 March 2007,Washington, DC, U.S.A.).

77

800600400200

0

175150

100

50

0

140120

80

40

0

150

50100

200

0

MeV/Nucl MeV/Nucl MeV/Nucl

MeV/Nucl

MeV/Nucl

MeV/Nucl

MeV/Nucl

MeV/Nucl

MeV/Nucl

MeV/Nucl

Si8-N4 Si9 C4

Si11

Si13

O6Si10-N5

Si12-N6

Si14-N7-C6-O8

C5

0.5 1.5 2.51 2

0.5 1.5 2.51 2

0.5 1.5 2.51 2 3

0.50.4 0.6 0.7 0.8 0.9

0.5 0.6 0.7 0.8 0.9 1.11

60

40

20

00.4 0.6 0.8 1.2 1.41

20

10

0

15

5

0.2 0.4 0.6 0.8 1.2 1.4 1.61

0.2 0.4 0.6 0.8 1.2 1.41

0.4 0.6 0.8 1.2 1.410.6 0.8 1.2 1.41

30

20

10

0

30

20

10

0

3040

2010

0

800600400200

0

Fig. A5.5 – Example of ion distribution function

calculations for a Thomson ion spectrometer

0.325

0.195

0.065

2 6 10 14

SiN

Z

Fig. A5.6 – Example of ionization distribution functions

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A6.1 Publications

Articles

G. VLAD, S. BRIGUGLIO, G. FOGACCIA, F. ZONCA, M. SCHNEIDER: Alfvénic instabilities driven by fusiongenerated alpha particles in ITER scenariosNucl. Fusion 46, 1-16 (2006)

G. CARUSO, H.W. BARTELS, M. ISELI, R. MEYDER, S. NORDLINDER, V. PASLER, M.T. PORFIRI:Simulation of cryogenic He spills as basis for planning of experimental campaign in the EVITA facilityNucl. Fusion 46, 51-56 (2006)

A.A. TUCCILLO, F. CRISANTI, X. LITAUDON, YU.F. BARANOV, A. ECOULET, M. BECOULET, L. BERTALOT,C.D. CHALLIS, R. CESARIO, M.R. DE BAAR, P.C. DE VRIES, B. ESPOSITO, D. FRIGIONE, L. GARZOTTI, E.GIOVANNOZZI, C. GIROUD, G. GORINI, C. GORMEZANO, N.C. HAWKES, J. HOBIRK, F. IMBEAUX, E.JOFFRIN, P.J. LOAS, J. MAILLOUX, P. MANTICA, M.J. MANTSINEN, D. MAZON, D. MOREAU, A. MURARI, V.PERICOLI-RIDOLFINI, F. RIMINI, A.C.C. SIPS, O. TUDISCO, D. VAN EESTER, K.-D. ZASTROW AND JET-

EFDA WORK-PROGRAMME CONTRIBUTORS: Development on JET of advanced tokamak operation for ITER

Nucl. Fusion 46, 214-224 (2006)

F. SANTINI: Non-thermal fusion in a beam plasma systemNucl. Fusion 46, 225-231 (2006)

P. BATISTONI, U. FISCHER, M. ANGELONI, P. BEM, I. KODELI, P. PERESLAVTSEV, L. PETRIZZI, M.PILLON, K. SEIDEL, S. P. SIMAKOV, R. VILLARI: Neutronics design and supporting experimental activitiesin the EU Fusion Eng. Des. 81, 1169-1181 (2006)

M. ANGELONE, P. BATISTONI, M. LAUBENSTEIN, L. PETRIZZI, M. PILLON: Neutronics experiment for thevalidation of activation properties of DEMO materials using real DT neutron spectrum at JETFusion Eng. Des. 81, 1485-1490 (2006)

M.T. PORFIRI, N. FORGIONE, S. PACI, A. RUFOLONI: Dust mobilization experiments in the context of thefusion plants - STARDUST facilityFusion Eng. Des. 81, 1353-1358 (2006)

T. PINNA, J. IZQUIERDO, M.T. PORFIRI, J. DIES: Fusion component failure rate database (ECFR-DB)Fusion Eng. Des. 81, 1391-1395 (2006)

L. PETRIZZI, M. ANGELONE, P. BATISTONI, U. FISCHER, M. LOUGHLIN, R. VILLARI: Benchmarking ofMonte Carlo based shutdown dose rate calculations applied in fusion technology: from the past experiencea future proposal for JET 2005 operationFusion Eng. Des. 81, 1417-1423 (2006)


A6 Publications, Patents and Events


M. ANGELONE, M. PILLON, A. BALDUCCI, M. MARINELLI, E. MILANI, M.E. MORGADA, G. PUCELLA,A. TUCCIARONE, G. VERONA-RINATI, K. OCHIAI, T. NISHITANI: Radiation hardness of a polycrystalline chemical-

vapor-deposited diamond detector irradiated with 14 MeV neutrons

Rev. Sci. Instrum. 77, 023505/1-7 (2006)

C. CASTALDO, U. DE ANGELIS, V.N. TSYTOVICH: Screening and attraction of dust particles in plasmas Phys. Rev. Letts 96, 075004/1-4 (2006)

S. TOSTI, L. BETTINALI, F. GIORDANO, E. SOLDANO, G. SCIOCCHETTI: A novel permeation method to measurevolumes Measurement 39, 186-194 (2006)

S.E. SEGRE, V. ZANZA: Derivation of the pure Faraday and Cotton-Mouton effects when polarimetric effects in aTokamak are large Plasma Phys. Control. Fusion 48, 339-351 (2006)

G. MICCICHÉ, G. COLLINA, L. MURO, B. RICCARDI: IFMIF repraceable backplate: remote handling activities,rescue procedures and evaluation of a prototype reliabilityFusion Eng. Des. 81, 879-885 (2006)

M. SAMUELLI, L. RAPEZZI, M. ANGELONE, M. PILLON, M. RAPISARDA, S. VITULLI: Unconventional plasmafocus devices IEEE Trans. Plasma Sci. 34, 1, 36-54 (2006)

A. BALDUCCI, M. MARINELLI, E. MILANI, M.E. MORGADA, G. PUCELLA, M. SCOCCIA, A. TUCCIARONE, G.VERONA-RINATI, M. ANGELONE, M. PILLON, R.POTENZA, C. TUVÉ: Growth and characterization of singlecrystal CVD diamond film based nuclear detectorsDiamond Rel. Mater. 15, 292-295 (2006)

F. ZONCA, L. CHEN: Resonant and non-resonant particle dynamics in Alfvén mode excitations Plasma Phys. Control. Fusion 48, 537-556 (2006)

L. BERTALOT, B. ESPOSITO, Y. KASCHUCK, D. MAROCCO, M. RIVA, A. RIZZO, D. SKIPINTSEV: Fast digitizingtechniques applied to scintillation detectorsNucl. Phys. B (Proc. Suppl.) 150, 78-81 (2006)

D. MAISONNIER, I. COOK, P. SARDAIN, L. BOCCACCINI, L. DI PACE, L. GIANCARLI, NORJAITRA PRACHAI, A.

PIZZUTO AND PPCS TEAM: DEMO and fusion power plant conceptual studies in Europe

Fusion Eng. Des. 81, 1123-1130 (2006)

M. ROMANELLI, F. BOMBARDA, C. BOURDELLE, M. DE BENEDETTI, B. ESPOSITO, D. FRIGIONE, C.GORMEZANO, E. GIOVANNOZZI, G.T. HOANG, M. LEIGHEB, M. MARINUCCI, D. MAROCCO, C. MAZZOTTA, G.REGNOLI, C. SOZZI, F. ZONCA: Confinement and turbulence study in the Frascati tokamak upgrade high field and

high density plasmas

Nucl. Fusion 46, 412-418 (2006)

P. BATISTONI: Il contributo italiano a ITER e al programma fusione La Termotecnica, Anno LX, 5, 32-34 (2006)

S. TOSTI, A. BASILE, F. BORGOGNONI, L. BETTINALI, C. RIZZELLO: Pd membrane reactor design

Desalination 200, 676-678 (2006)

S. TOSTI, L. BETTINALI: Volumes measurement by means of membranes Desalination 200, 140-141 (2006)

P. BURATTI, B. ALPER, S.V. ANNIBALDI, A. BECOULET, P. BELO, J. BUCALOSSI, M. DE BAAR, P. DE VRIES,

A

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D. FRIGIONE, C. GOMERZANO, E. JOFFRIN, P. SMEULDERS AND JET EFDA CONTRIBUTORS: Study of

slow n=1, m=1 reconnection in JET discharges with low central magnetic shear

Plasma Phys. Control. Fusion 48, 1005-1018 (2006)

R. CESARIO, A. CARDINALI, C. CASTALDO, F. PAOLETTI, V. FUNDAMENSKI, S. HACQUIN: Spectralbroadening induced by parametric instability in lower hybrid current drive experiments of tokamak plasmas Nucl. Fusion 46, 462-476 (2006)

F. ALLADIO, P. COSTA, A. MANCUSO, P. MICOZZI, S. PAPASTERGIOU, F. ROGIER: Design of the Proto-Sphera experiment and of its first step (MULTI-PINCH)Nucl. Fusion 46, S613-S624 (2006)

S. TOSTI, A. BASILE, L. BETTINALI, F. BORGOGNONI, F. CHIARAVALLOTI, F. GALLUCCI: Long-term testsof Pd-Ag thin wall permeator tube J. Membrane Sci. 284, 393-397 (2006)

M. MATTIOLI, G. MAZZITELLI, K.B. FOURNIER, M. FINKENTHAL, L. CARRARO: Updating of atomic dataneeded for ionization balance evaluations of krypton and molybdenum J. Phys. B: At. Mol. Opt. Phys. 39, 4457-4489 (2006)

A. BASILE, S. TOSTI, G. CAPANNELLI, G. VITULLI, A. IULIANELLI, F. GALLUCCI, E. DRIOLI: Co-current

and counter-current modes for methanol steam reforming membrane reactor: experimental study

Catalysis Today 118, 237-245 (2006)

A. BASILE, F. GALLUCCI, A. IULIANELLI, S. TOSTI, E. DRIOLI: The pressure effect on ethanol steam

reformig in membrane reactor: experimental study Desalination 200, 671-672 (2006)

F. ZONCA, S. BRIGUGLIO, L. CHEN, G. FOGACCIA, T.S. HAHM, A.V. MILOVANOV, G. VLAD: Physics ofburning plasmas in toroidal magnetic confinement devicesPlasma Phys. Control. Fusion 48, B15-B28 (2006)

M. CIOTTI, A. NIJHUIS, P.L. RIBANI, L. SAVOLDI RICHARD, R. ZANINO: THELMA code electromagnetic

model of ITER superconducting cables and application to the ENEA stability experiment

Supercond. Sci. Technol 19, 987-997 (2006)

U. DE ANGELIS, G. CAPOBIANCO, C. MARMOLINO, C. CASTALDO: Fluctuations in dusty plasmas

Plasma Phys. Control. Fusion 48, B91-B97 (2006)

A. FRATTOLILLO: New simple method for fast and accurate measurement of volumes

Rev. Sci. Instrum 77, 045107 (2006)

F. ALLADIO, P. MICOZZI: Behaviour of perturbed plasma displacement near regular and singular X-points

for compressible ideal MHD stability analysis

Phys. Plasmas 13, 082505 (2006)

A. FRATTOLILLO: A simple automatic device for real time sampling of gas production by a reactor

Rev. Sci. Instrum. 77, 065108 (2006)

M.I.K. SANTALA, M.J. MANTSINEN, L. BERTALOT, S. CONROY, V. KIPTILY, S. POPOVICHEV, A. SALMI, D.TESTA, YU BARANOV, P. BEAUMONT, P. BELO, J. BRZOZOWSKI, M. CECCONELLO, M. DE BAAR, P. DEVRIES, C. GOWERS, J-M. NOTERDAEME, C. SCHLATTER, S. SHARAPOV AND JET-EFDA

CONTRIBUTORS: Proton-triton nuclear reaction in ICRF heated plasmas in JET

Plasma Phys. Control. Fusion 48, 1233-1253, (2006)




S.E. SEGRE, V. ZANZA: Incident electromagnetic wave polarization and the resulting mode purity insidemagnetized plasma Plasma Phys. Control. Fusion 48, 599-607 (2006)

C. STRANGIO, A. CARUSO, S. YU. GUS’KOV, V.B. ROZANOV, A.A. RUPASOV: Interaction of a smoothed laserbeam with supercritical-density porous targets on the ABC facilityQuantum Electr. 36, 3, 424-428 (2006)

R. BEDOGNI, A. ESPOSITO, M. ANGELONE, M. CHITI: Determination of the response to photons and thermalneutrons of new LiF based TL materials for radiation protection purposesIEEE Trans. Nucl. Sci. 53, 3, 1367-1370 (2006)

M. ANGELONE, M. MARINELLI, E. MILANI, A. TUCCIARONE, M. PILLON, G. PUCELLA, G. VERONA-RINATI:Neutron detection and dosimetry using polycrystalline CVD diamond detectors with high collection efficiencyRadiat. Prot. Dosim. 120, 1-4, 345-348 (2006)

R. BEDOGNI, M. ANGELONE, A. ESPOSITO, M. CHITI: Inter-comparison among different TLD-based techniquesin a standard multisphere assembly for the characterisation of neutron fieldsRadiat. Prot. Dosim. 120, 1-4, 369-372 (2006)

Articles in course of publication

P. BATISTONI: L’eredità di Chernobyl: i recenti rapporti del Chernobyl forum sulle conseguenze sulla salutesull’ambiente e sul sistema socio-economico a vent’anni dell’incidenteEnergia, Ambiente e Innovazione

J.R. MARTIN-SOLIS, B. ESPOSITO, R. SANCHEZ, F.M. POLI, L. PANACCIONE: Enhanced production of runaway

electrons during disruptive termination of discharges heated with lower hybrid power in the Frascati TokamakUpgradePhys. Rev. Letts

A. VANNOZZI, A. RUFOLONI, G. CELENTANO, A. AUGIERI, L. CIONTEA, F. FABBRI, V. GALLUZZI, U.GAMBARDELLA, A. MANCINI, T. PETRISOR: Cube textured substrates for YBCO coated conductors:microstructure evolution and stabilitySupercond. Sci. Technol.

A. AUGIERI, G. CELENTANO, U. GAMBARDELLA, L. CIONTEA, V. GALLUZZI, T. PETRISOR, J. HALBITTER:Analysis of angular dependence of pinning mechanisms on casubstituted YBa2Cu3O7-δ epitaxial thin filmsSuperconductors Sci. Technol.

M. DE BENEDETTI AND JET EFDA CONTRIBUTORS: Observation of an intermediate rotation regime on JETNucl. Fusion

C. CASTALDO, S. RATYNSKAIA, V. PERICOLI, U. DE ANGELIS, L. PIERONI, E. GIOVANNOZZI, C. MARMOLINO,

A. TUCCILLO, G.E. MORFILL: Effects of dust on electrostatic probe signal in tokamak plasmasNucl. Fusion

S. TOSTI, A. BASILE, F. BORGOGNONI, L. BETTINALI, F. GALLUCCI, C. RIZZELLO: Design and process study ofPd membrane reactorsJ. Membrane Sci.

M. ROMANELLI, G.T. HOANG, C. BOURDELLE, C. GORMEZANO, E. GIOVANNOZZI, M. LEIGHEB, M. MARINUCCI,

D. MAROCCO, C. MAZZOTTA, L. PANACCIONE, V. PERICOLI, G. REGNOLI, O. TUDISCO AND THE FTU TEAM:

Parametric dependence of turbulent particle-transport in high-density electron heated tokamak plasmasPlasma Phys. Control. Fusion

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M. ROMANELLI, M. LEIGHEB, L. GABELLIERI, L. CARRARO, M.E. PUIATTI, M. MATTIOLI, L. LAURO-TARONI, M. DE BENEDETTI, M. MARINUCCI, C. MAZZOTTA, L. PANACCIONE, G. REGNOLI, P.SMEULDERS, O. TUDISCO, S. NOVAK, C. SOZZI, M. VALISA, AND THE FTU TEAM: Turbulenttransport of heavy impurities in tokamak electron heated high density plasmas: a study of FTUdischargesPlasma Phys. Control. Fusion

D. FRIGIONE, L. GARZOTTI, C.D. CHALLIS, M. DE BAAR, P. DE VRIES, M. BRIX, X. GARBET, N. HAWKES,

A. THYAGARAJA, L. ZABEO, AND JET EFDA CONTRIBUTORS: Pellet injection and high density ITBformation in JET advanced tokamak plasmas

Nucl. Fusion

Contributions to conferences

F. MIRIZZI, PH. BIBET, G. CALABRÒ, V. PERICOLI RIDOLFINI, A.A. TUCCILLO: PAM, MJ and conventionalgrills: operative experience on FTU

24th Symposium on Fusion Technology (SOFT), Warsaw (Poland), September 11-15, 2006

G.L. RAVERA, C. CASTALDO, R. CESARIO, S. LUPINI, S. PODDA, G.B. RIGHETTI AND FTU TEAM: Highpower RF components for IBW experiment on FTU


O. TUDISCO, C. MAZZOTTA, M.L. APICELLA, G.G. MAZZITELLI, G. MONARI, G. ROCCHI: Density profilestudies of plasmas with lithium limiter

33rd EPS Conference on Plasma Physics, Rome (Italy), June 19-23, 2006

C. CASTALDO, R. CESARIO, A. CARDINALI, M. MARINUCCI, P. MICOZZI, L. PANACCIONE, M. ANANIA, S. DIFLAURO, B. EUSEPI, L. PAJEWSKI, G. SCHETTINI, G. GIRUZZI AND THE JET EFDA CONTRIBUTORS:Modelling of experiments with ITER-relevant q-profile control at high βN by means of the lower hybrid current drive


F. ZONCA, S. BRIGUGLIO, L. CHEN, G. FOGACCIA, T.S. HAHM, A.V. MILOVANOV, G. VLAD: Physics of

burning plasmas in toroidal magnetic confinement devices

33rd EPS Conference on Plasma Physics, Rome (Italy), June 19-23, 2006 (Invited Paper)

B. ESPOSITO, M. RICCI, D. MAROCCO, Y. KASCHUCK: A digital acquisition and elaboration system fornuclear fast pulse detectionX Pisa 2006 Meeting on Advanced Detectors, La Biodola, Isola d’Elba (Italy), May 21-27, 2006

O. TUDISCO, G. GROSSETTI, C. SOZZI: Oblique ECE diagnostic on FTU

14th Joint Workshop on “Electron Cyclotron Emission and Electron Cyclotron Resonance Heating,Santorini Island (Greece), May 9-12, 2006

A. CARDINALI, B. ESPOSITO, F. RIMINI, M. BRAMBILLA, F. CRISANTI, M. DE BAAR, E. DE LA LUNA, P.DE VRIES, X. GARBERT, G. GIROUD, E. JOFFRIN, P. JOFFRIN, P. MANTICA, M. MANTSINEN, A. SALMI,C. SOZZI, D. VAN EESTER AND JET EFDA CONTRIBUTORS: Modeling and analysis of the ICRH heatingexperiments in JET ITB regimes


M.L. APICELLA, G. MAZZITELLI, V. PERICOLI-RIDOLFINI, V. LAZAREV, A. ALEKSEYEV, A. VERTKOV, R.

ZAGÒRSKI AND FTU TEAM: First experiments with lithium limiter on FTU

17th Conference on Plasma Surface Interactions (PSI), Hefei Anhui (China), May 22-26, 2006




G. MADDALUNO, G. GIACOMI, A. RUFOLONI, L. VERDINI: Tungsten macrobrush sample exposure in FTU tokamak

17th Conference on Plasma Surface Interactions (PSI), Hefei Anhui (China), May 22-26, 2006

V. MASSAUT, L. DI PACE, L. OOMS, K. BRODÉN, R.A. FORREST, M. ZUCCHETTI: The role of clearance in themanagement of future fusion reactor radioactive materials

4th Symposium Release of Radioactive Material from Regulatory Control, “Harmonisation of Clearance Levels andRelease procedures”, Hamburg (Germany), March 20-22, 2006

S. TOSTI, A. BASILE, F. BORGOGNONI, L. BETTINALI, C. RIZZELLO: Pd membrane reactor design

Euromembrane 2006, Taormina (Italy), September 24-28, 2006

U. DE ANGELIS, G. CAPOBIANCO, C. MARMOLINO, C. CASTALDO: Fluctuations in dusty plasmas

33rd EPS Conference on Plasma Physic, Rome (Italy), June 19-23, 2006 (Invited Paper)

V. PERICOLI-RIDOLFINI, A. ALEKSEYEV, B. ANGELINI, S.V. ANNIBALDI, M.L. APICELLA, G. APRUZZESE, E.BARBATO, J. BERRINO, A. BERTOCCHI, W. BIN, F. BOMBARDA, G. BRACCO, A. BRUSCHI, P. BURATTI, G.CALABRÒ, A. CARDINALI, L. CARRARO, C. CASTALDO, C. CENTIOLI, R. CESARIO, S. CIRANT, V. COCILOVO,F. CRISANTI, G. D’ANTONA, R. DE ANGELIS, M. DE BENEDETTI, F. DE MARCO, B. ESPOSITO, D. FRIGIONE, L.GABELLIERI, F. GANDINI, E. GIOVANNOZZI, G. GRANUCCI, F. GRAVANTI, G. GROSSETTI, G. GROSSO, F.IANNONE, H. KROEGLER, V. LAZAREV, E. LAZZARO, M. LEIGHEB, L. LUBYAKO , G. MADDALUNO, M.MARINUCCI, D. MAROCCO, J.R. MARTIN-SOLIS , G. MAZZITELLI, C. MAZZOTTA, V. MELLERA, F. MIRIZZI, G.MONARI, A. MORO, V. MUZZINI, S. NOWAK, F. ORSITTO, L. PANACCIONE, M. PANELLA, L. PIERONI, S.PODDA, M. E. PUIATTI, G. RAVERA, G. REGNOLI, F. ROMANELLI, M. ROMANELLI, A. SHALASHOV, A.SIMONETTO, P. SMEULDERS, C. SOZZI, E. STERNINI, U. TARTARI, B. TILIA, A.A. TUCCILLO, O. TUDISCO, M.

VALISA, A. VERTKOV , V. VITALE, G. VLAD, R. ZAGÓRSKI , F. ZONCA: Overview of the FTU results

21st IAEA Conference on Fusion Energy, Chengdu (China), October 16-22, 2006

G. MAZZITELLI, M.L. APICELLA, C. MAZZOTTA, V. PERICOLI RIDOLFINI. O. TUDISCO, V. LAZAREV, A.ALEKSEYEV, A. VERTKOV, R. ZAGORSKI, AND FTU TEAM: Lithium as a liquid limiter in FTU


L. CHEN, F. ZONCA: Nonlinear equilibria, stability and generation of zonal structures in toroidal plasmas


L. CHEN, F. ZONCA: Theory of Alfvén waves and energetic particle physics in burning plasmas


F.P. ORSITTO, J–M. NOTERDAEME, A.E. COSTLEY, A.J. DONNÉ AND ITPA TG ON DIAGNOSTICS: Requirementsfor fast particle measurements on ITER and candidate measurement techniques


F. CRISANTI, A. BECOULET, P. BURATTI, E. GIOVANNOZZI, C. GORMEZANO, E. JOFFRIN, A. SIPS, C.BOURDELLE, A. CARDINALI, C. CHALLIS, N. HAWKES, J. HOBIRK, X. LITAUDON, G. REGNOLI, M. ROMANELLI,A. THYAGARAJA, A. TUCCILLO, AND JET EFDA CONTRIBUTORS: JET hybrid scenarios with improved coreconfinement


G. VLAD, S. BRIGUGLIO, G. FOGACCIA, K. SHINOHARA, M. ISHIKAWA, M. TAKECHI, F. ZONCA: Particlesimulation analysis of energetic-particle and Alfvén-mode dynamics in JT-60U discharges


F. ZONCA, P. BURATTI, A. CARDINALI, L. CHEN, J.–Q. DONG, Y.–X. LONG, A. MILOVANOV, F. ROMANELLI, P.

SMEULDERS, L. WANG, Z.–T. WANG: Electron fishbones: theory and experimental evidence


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V. PERICOLI-RIDOLFINI, M. L. APICELLA, G. MAZZITELLI, O. TUDISCO, R. ZAGÓRSKI AND FTU TEAM:

Edge properties with the liquid lithium limiter in FTU – experiment and transport modellingWorkshop on Edge Transport in Fusion Plasmas (ETFP), Cracovia (Poland), September 11-13, 2006

V. PERICOLI–RIDOLFINI, P. BURATTI, G. CALABRÒ, M. DE BENEDETTI, B. ESPOSITO, L. GABELLIERI, G.GRANUCCI, M. LEIGHEB, M. MARINUCCI, D. MAROCCO, C. MAZZOTTA, F. MIRIZZI, S. NOWAK, L.PANACCIONE, G. REGNOLI, M. ROMANELLI, P. SMEULDERS, C. SOZZI, O. TUDISCO, A.A. TUCCILLO:Internal transport barriers in FTU at ITER relevant plasma density with pure electron heating and current drive


A. CARDINALI, F. ROMANELLI: Simulation of burning plasma dynamics by ICRH accelerated minority ions


A. BERTOCCHI, C. CENTIOLI, M. DI DONNA, F. IANNONE, M. PANELLA, L. PANGIONE, V. VITALE, L.

ZACCARIAN: The new FTU continuous monitoring system with Mac OS X technologiesApple WWDC06 Conference, San Francisco (USA), August 7-11, 2006

G. VLAD, S. BRIGUGLIO, G. FOGACCIA, F. ZONCA: Interaction of fast particles and Alfvén modes inburning plasmasJoint Varenna-Lausanne International Workshop on Theory of Fusion Plasmas, Villa Monastero, Varenna(Italy), August 28 - September 1, 2006

V. GALLUZZI, A. AUGIERI, L. CIONTEA, G. CELENTANO, F. FABBRI, U. GAMBARDELLA, A. MANCINI, T.

PETRISOR, N. POMPEO, A. RUFOLONI, E. SILVA, A. VANNOZZI: YBCO films with BZO inclusions forstrong-pinning in superconducting films on single crystal substrateApplied Superconductivity Conference (ASC 2006), Seattle WA (USA), August 28 - Setpember 1, 2006

S. TOSTI, L. BETTINALI: Volumes measurement by means of membranesEuromembrane 2006, Taormina (Italy), September 24-28, 2006

A. VANNOZZI, A. AUGIERI, G. CELENTANO, F. FABBRI, V. GALLUZZI, U. GAMBARDELLA, A. MANCINI, T.

PETRISOR, A. RUFOLONI: Cube textured substrates for YBCO coated conductors: influence of initial grain

size and strain conditions during tape rollingApplied Superconductivity Conference (ASC 2006), Seattle WA (USA), August 28 - Setpember 1, 2006

A. CARDINALI, L. MORINI, F. ZONCA: Analysis of the validity of the asymptotic techniques in the lower

hybrid wave equation solution for reactor aplicationsJoint Varenna-Lausanne International Workshop on Theory of Fusion Plasmas, Villa Monastero, Varenna(Italy), August 28 - September 1, 2006

A. BERTOCCHI, M. DI DONNA, M. PANELLA, V. VITALE: The liquid lithium limiter control system on FTU


V. VITALE, C. CENTIOLI, F. IANNONE, M. PANELLA, L. PANGIONE, M. SABATINI, L. ZACCARIAN, R.ZUCCALÀ: SA matlab based framework for the real-time environment at FTU


V. MASSAUT, R. BESTWICK, K. BRODEN, L. DI PACE, L. OOMS, R. PAMPIN: State of the art of fusionmaterial recycling and remaining issues


M. ANGELONE, L. PETRIZZI, M. PILLON, S. POPOVICHEV, R. VILLARI: Dose rate experiment at JET forbenchmarking the calculation direct one step method24th Symposium on Fusion Technology (SOFT), Warsaw (Poland), September 11-15, 2006




C. NERI, L. BARTOLINI, M. FERRI DE COLLIBUS, G. FORNETTI, F. POLLASTRONE, M. RIVA, L. SEMERARO: Thelaser in vessel viewing system (IVVS) for ITER: test results on first wall and divertor samples and new developments


L. DI PACE, T. PINNA: Assessment of occupational radiation exposure (ORE) for hands-on assistance to theremote handling at ITER ports and waste treatment


M. SANTINELLI, R. CLAESEN, A. COLETTI. T. BONICELLI, P.L. MONDINO, M. PRETELLI, L. RINALDI, L. SITA, G.

TADDIA: Solid state gyrotron body power supply, test results24th Symposium on Fusion Technology (SOFT), Warsaw (Poland), September 11-15, 2006

P. BATISTONI, M. ANGELONE, L. BETTINALI, P. CARCONI, U. FISCHER, I. KODELI, D. LEICHTLE, K. OCHIAI, R.

PEREL, M. PILLON, I. SCHÄFER, K. SEIDEL, Y. VERZILOV, R. VILLARI, G. ZAPPA: Neutronics experiment on a

HCPB breeder blanket mock-up


T. PINNA, G. CAMBI, F. GRAVANTI: Collection and analysis of component failure data from JET systems

8th IAEA Technical Meeting on “Fusion Power Plant Safety”, Wien (Austria), July 10-13, 2006

F. ALLADIO, P. COSTA, A. MANCUSO, P. MICOZZI, R. AKERS, G. CUNNINGHAM, M. GRYAZNEVICH, M. HOOD,G. MC ARDLE, V. SHEVCHENKO, A. SYKES, F. VOLPE, A. DNESTROVSKIJ: Status and perspectives of MASTstart-up in the absence of solenoid flux


G. REGNOLI, M. ROMANELLI, C. BOURDELLE, M. DE BENEDETTI, M. MARINUCCI, V. PERICOLI, G. GRANUCCI, C.

SOZZI, O. TUDISCO, E. GIOVANNOZZI, ECRH, LH AND FTU TEAM: Microstability analysis of collisional plasmas


E. GIOVANNOZZI, C. CASTALDO, G. MADDALUNO: Evidence of dust in FTU from Thomson scattering diagnosticmeasurements


G. FOGACCIA, S. BRIGUGLIO, M. ISHIKAWA, K. SHINOHARA, M. TAKECHI, G. VLAD, F. ZONCA: Particlesimulations of energetic particle driven Alfvèn modes in JT-60U


J.R. MARTIN-SOLIS, B. ESPOSITO, R. SANCHEZ, F.M. POLI, L. PANACCIONE: Runaway current plateau

formation during disruptions in the FTU Tokamak


B. ESPOSITO, G. GRANUCCI, S. NOWAK, P. SMEULDERS, J. BERRINO, J.R. MARTIN-SOLIS, R. SANCHEZ, L.GABELLIERI, M. LEIGHEB, F. GANDINI, D. MAROCCO, C. MAZZOTTA, O. TUDISCO: Disruption mitigation

experiments in FTU using ECRH


M. ROMANELLI, G.T. HOANG, C. BOURDELLE, C. GORMEZANO, E. GIOVANNOZZI, M. LEIGHEB, M.MARINUCCI, D. MAROCCO, C. MAZZOTTA, L. PANACCIONE, V. PERICOLI, G. REGNOLI, O. TUDISCO, AND

THE FTU TEAM: Parametric dependence of turbulent particle transport in high collisionality plasmas on the

Frascati Tokamak Upgrade FTU


M. ROMANELLI, M. LEIGHEB, L. GABELLIERI, L. CARRARO, M.E. PUIATTI, M. VALISA, M. MATTIOLI, L. LAURO-TARONI, M. DE BENEDETTI, M. MARINUCCI, C. MAZZOTTA, G. REGNOLI, P. SMEULDERS, S. NOVAK, C.

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SOZZI: Investigation of turbulent transport of heavy impurities in FTU electron heated plasmas


G. CALABRÒ, V. PERICOLI-RIDOLFINI, L. PANACCIONE AND FTU TEAM: Effect of the scattering from

edge density fluctuations on the lower hybrid waves in FTU


M. RIVA, B. ESPOSITO, D. MAROCCO: A new pulse-oriented digitial aquisition system for nucleardetectors


M. PILLON. M. ANGELONE, D. LATTANZI, M. MARINELLI, E. MILANI, A. TUCCIARONE, G. VERONA-RINATI, S. POPOVICHEV, R.M. MONTEREALI, M.A. VINCENTI, A. MURATI AND JET -EFDACONTRIBUTORS: Neutron detection at JET using artificial diamond detectors


C. CASTALDO, U. DE ANGELIS, V.N. TSYTOVICH: Screening and attraction of dust particles in plasmas


M.L. APICELLA, M. LEGHEB, M. MARINUCCI, G. MAZZITELLI, FTU TEAM, V. LAZAREV, A. ALEKSEYEV,A. VERTKOV: Energy balance of FTU discharges with lithizated walls

33rd EPS Conference on Plasma Physics, Rome (Italy) June 19-23, 2006

S.V. ANNIBALDI, F. ZONCA, P. BURATTI: Excitation of beta-induced Alfvèn eigenmodes in the presence of

a magnetic island


E. VISCA, S. LIBERA, A. MANCINI, G. MAZZONE, A. PIZZUTO, C. TESTANI: Pre-brazed casting and hotradial pressing: a reliable process for the manufacturing of CFC and W monoblock mockups


Reports

RT/ 2006/35/FUS R. CHIRICOStudio sui rischi per la sicurezza e per la salute associati all’utilizzo di un limiter dilitio durante le sperimentazioni con FTU (Frascati Tokamak Upgrade)

RT/2006/69/FPN R. CHIRICO

Teorie e parametrizzazioni per la ripartizione degli IPA su particolato atmosferico:stato dell’arte

A6.2 Patents

RM2006A000429 A. DELLA CORTE, A. DI ZENOBIO

Procedimento per la realizzazione di un giunto tra cavi superconduttori di tipoCICC a basso livello di ingombro, bassa resistenza elettrica e basso costo direalizzazione




RM2006A000314 L. BETTINALI, V. VIOLANTE, F. SARTO, C. SIBILIA, M. BERTOLOTT, E. CASTAGNA, I.DARDIK, S.LESIN, T. ZILOV, M. TSIRLIN

Materiali laminati metallici con inclusioni di materiale dielettrico per l’amplificazione ed ilcontrollo del campo elettrico di interfase, e relativo processo di produzione

RM2006A000102 S. TOSTI, D. LECCI, C. RIZZELLO, A. BASILE

Procedimento a membrana per la produzione di idrogeno da reforming di compostiorganici, in particolare idrocarburi o alcoli

A6.3 Conferences and Events

June 19-23, 2006 33rd European Physics Society - Conference on Plasma PhysicsRome (Italy)

A6.4 Seminars

21/03/2006 S. ORTOLANI - Consorzio RFX - ENEA - Padova, ItalyActive MHD control experiments in RFX - mod

24/03/2006 J. KASAGI – LNS, Tohoku University - Tohoku, JapanLow energy nuclear reactions in condensed matter

28/04/2006 S. MIRNOV - TRINITI - Troitsk, Russia Test of the lithium capillary - pore system (CPS) as tokamak limiter and DEMO perspective of Li CPS

10/07/2006 M. TESSAROTTO - Università di Trieste - Trieste, Italy Il problema di Debye per plasmi debolmente e fortemente accoppiati

25/09/2006 M. SHOUCRI - IREQ - Varennes, Quebec, CanadaStudy of a turbulent spectrum at the edge of a 2D plasma slab in the gyrokinetic approximation

13/12/2006 P. SCARIN - Consorzio RFX - Padova, ItalyEdge turbulence evidence in RFX - mod with GPI diagnostic

13/12/2006 A. SANTUCCI - Università “Tor Vergata” - Roma, ItalyReforming di etanolo in reattori a membrana

19/12/2006 S. GERASSIMOV - Technical Univ. of Münich and CERN - Münich, GermanyUse of ROOT to store large quantities of scientific data

13/12/2006 V. CAPALDO - Università “La Sapienza” - Roma, Italy Reforming di etanolo in reattori a membrana

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B1.1 Innovative Fuel Cycles Including Partitioning andTransmutation

Activities on partition and transmutation started under the 5th European Framework Programme(FP5) and have continued under FP6. The work on chemical partitioning was carried out under theEuropean Research Programme for the Partitioning of Minor Actinides (EUROPART) concerning thepartitioning of long-lived radionuclides (LLRNs) contained in the nuclear waste resulting from thereprocessing of spent nuclear fuel. After separation, the LLRNs will be destroyed by nuclear meansso as to become short-lived or stable nuclides or conditioned into stable dedicated solid matrices.Transmutation activities were carried out under the European Transmutation (EUROTRANS) projectsubmitted by ENEA, Commissariat à l’Energie Atomique (CEA), Forschungszentrum Karlsruhe (FZK)and the Belgian Nuclear Research Centre (SCK-CEN). The objectives are to demonstrateexperimentally the accelerator driven system (ADS) operations and dynamic characteristics and thento deliver a conceptual design for a European Transmutator Demonstrator (ETD), including its overalltechnical feasibility, and to perform an economic assessment.

ENEA coordinates the European Virtual European Lead Initiative (VELLA) project, which has theambitious intent to homogenize the European research area in the field of leading technologies fornuclear applications in order to produce a common platform of work that will continue also after theend of the initiative. The issues of this activity are also of interest to evolutionary and innovativereactor activities (see B1.2).

Studies on innovative uranium-free inert matrix and thorium fuels, aimed at in-reactor plutoniumincineration either in the current light-water reactors (LWRs) or in next-generation reactors, werecontinued in 2006. ENEA researchers participated in a first evaluation of the experimental data fromthe IFA-652 irradiation test performed up to the end of 2005 in the Halden Material Test Reactor(Norway). A good response of the proposed fuel concept was found, with an under-irradiationstability similar to that of UOX and MOX fuels, except for a somewhat higher fission gas release(FGR) rate. In parallel, implementation of the inert matrix fuel (IMF) basic thermo-physical propertiesand models on the fuel-rod performance code Transuranus was completed and a simulation of thefirst-phase of IFA-652 irradiation in Halden was performed. Preliminary modelling with Transuranuson CER-CER and CER-MET fuels for transmutation, started in 2005, was also continued.Dispersion of the fissile phase based on Pu and MAs oxides in Mg oxide matrix (CER-CER) or inmolybdenum metal matrix (CER-MET) was considered in the study.

Partitioning technology

The principal operation of chemical partitioning (fig. B1.1, [B1.1]) is electrorefining, which takes placein an electrochemical cell where dissolution of most of the fuel elements occurs. This is followed byselective electrodeposition of the actinides onto a solid and/or a liquid cathode through application

B1 R&D on Nuclear Fission



Ref

eren

ces

of an electrochemicaldifference among elementsin molten LiCl-KCl salt andliquid cadmium (orbismuth) under a high-purity argon atmosphere at773 K (pyro processing).The ex perimentalcampaigns concernedelectrorefining experimentswith the Pyrel II plant and

conditioning of chloride salt wastes arising from pyroprocessing of spent nuclear fuel.

Experimental campaigns. The Pyrel II facility [B1.2] was used to study the behaviour of lanthanum andcerium loaded on different anodes and electrotransported to different cathodes. The current was variedwhenever possible and both salt and metal phases were sampled. Seven experiments were performed:direct transportation from fuel dissolution basket (FDB) to solid steel cathode (SSC); anodic dissolution(from FDB to Bi pool); transportation from FDB to liquid bismuth cathode (LBC); direct (chemical)dissolution; transportation from Bi pool to SSC; transportation from Bi pool to LBC; salt clean-up betweenBi-Li anode and SSC.

Full evaluation of the results obtained is not easy at this stage, but a few considerations can be made:

• A cathode deposit is practically absent in any case.

• The electric current can be imposed only to a maximum specific value, depending on the type ofexperiment.

• The fuel dissolution basket extracted from the salt bath after the experiments with La ingots shows thatLa is still present in the FDB.

• Salt clean-up allows a significant amount of residual elements to be removed from the salt bath, withthe metals deposited at the Bi-Li anode, mainly around the magnesia vessel.

A real puzzle is the concentration of La and Ce in the chloride salt. It can be supposed that somethingother than the electric current is involved in the process. Clarification of the above and other importantquestions is mandatory for complete com prehension ofthe phenomena which take place during theelectrorefining experiments with Pyrel II, and for theproject of a new plant (Pyrel III) designed forelectrorefining with uranium ingots.

Chloride waste treatment. The pyrochemicalprocess produces a salt waste containing Li, K, and FPchlorides, which after several batches accumulate inthe molten salt media and represent an environmentalconcern because of their high water solubility. Sodalite,a naturally occurring mineral, is a major candidate forconditioning salt waste as it can incorporate chloridemetals in its cage-like structure. Hence pure sodalitewas prepared for use as reference material.

[B1.1] T. Nishimura et al., Progr. Nucl. Energy 32, 3/4, 381-387 (1998)

[B1.2] G. De Angelis and E. Baicchi, A new electrolyzer for pyrochemical process studies, Presented at the GLOBAL 2005 (Tsukuba 2005)

Spentfuel

Gas waste (T,Xe,Kr)

Salt, CdZr

Newfuel

Pincasting

Moldcrucible

Crucible

ElectrorefiningDisassembly

andchopping

Duct

Melting

Consolidation

Metal waste Salt waste (Cs,Sr,RE)

Immobilisation

TRUextraction

Clad, N MSpentsalt TRU

U-TRU-CD-salt

U, salt

Cathodeprocessing

TRU: Pu, Np, Am, CmRE: Rare earthNM: Noble metal

Fig. B1.1 – General schematic of spent

fuel reprocessing by pyrochemical

electrorefining (redrawn from ref. B1.1)

2000

1000

0

Cou

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s

10 30 50 70 902θ

Fig. B1.2 – X-ray diffraction spectrum related to the

formation of sodalite from chloride salt, silica and sodium

aluminate after 50 h of reaction

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Tests performed to prepare the sodalitestarting from silica and sodium aluminate(fig. B1.2) or from zeolite A (fig. B1.3) showthe formation of an intermediate phase,nepheline, which is known to be moreleachable with respect to other phases, likesodalite or pollucite. The role of microwavesand their effect on the reaction yield were alsostudied. Two different heating methods (insidea microwave oven or in a tubular oven) provedsuccessful, even if the reaction conditions aswell as the starting materials need a cleardefinition. The demonstration that the sameintermediate compound (nepheline) is presentin the synthesis of sodalite irrespective of themethod used was a success in itself.

The next step should be the synthesis of pure sodalite and localisation of the position of the variouscations inside the crystal lattice. While Li, Na, and K are presumably included in the structure ofsodalite, it is more difficult to identify the relative positions of ions such as Cs, Sr and Ba.

Transmutation systems and related technology

Research on transmutation was mainly focussed on:

• Neutronic design of a Pb-cooled European facility on an industrial-scale transmuter (EFIT – theEuropean Facility for Industrial Transmutation) (Domain Design).

• Study of the energetic gain expected in the Reactor-Accelerator Coupling Experiment (RACE)and on a new neutron detector for characterisation of the neutron spectrum in subcritical devices(Domain ECATS).

• Experimental activities to study the interaction between lead bismuth eutectic (LBE) and waterconsequent to heavy leaks due to a cooling tube rupture inside the steam generator and on alarge-scale integral test (Domain DEMETRA).

EFIT core design criteria: the “42-0” approach. Work concerned the neutronic analysis of theEFIT sub-critical reactor, in particular the preliminary definition of the core and fuel subassembly(S/A). Experience gained through the ANSALDO-ENEA collaboration in the Preliminary Design Study– Experimental Accelerator Driven System (PDS-XADS) project, a 80-MWth core cooled by LBE[B1.3], was exploited as far as possible. However, since the fuel (uranium-free, fig. B1.4a)) as wellas the goal of maximum rate minor-actinide (MA: Np, Cm, Am) burning are quite different from thePDS-XADS, an innovative approach was developed to deal with the core design and fuel cycle,mainly aimed at minimising the cost per kg of MAs burnt. Hence, a twofold strategy was assumed[B1.4]:

1. The so called “42-0” approach, i.e., the invariant 42 kg of fissioned material per TWhth have tobe MAs, whilst Pu is neither burnt (since it would be of low value in sub-critical reactors) nor bred(since this would be inconsistent with the uranium-free choice) and acts as a “catalyser”. Thisunivocally leads to fuel enrichment at about 45.7% in Pu, which represents the main startingparameter of the EFIT core design. In fact the Keff swing over the fuel cycle (which also mainlydepends on the fuel enrichment) has to be compatible with the proton accelerator performance.

2. The core size has to be optimised to obtain the minimum cost per fissioned kg of MAs. Since theburning rate per TWhth does not depend on the core size, the optimisation criterion (in the 42-0approach) becomes the minimum cost of the deployed power unit. Actually, the reactor unitarycost decreases with core size (in a certain range), whilst the accelerator cost is likely to increase,


90Progress Report 2006

2θ10 20 30 40 50 60 70

Tim

e

zeolite A

zos01

zos02

zos03

zos04

Fig. B1.3 – X-ray diffraction spectra related to the

formation of sodalite starting from zeolite A, at increasing

reaction times


mainly due to the loss of sourceefficiency. As the informationneeded for a possible trade-offwas missing, it was decided toassume the largest corecompatible with the presentdesign of the spallation module,as a simplified criterion.

The ANSALDO-develop ed [B1.4]800-MeV/20 mA spallation modulewhich can evacuate 11.2 MW ofpower (70% of the total beampower) was assumed as reference.The target is a windowless type (asin PDS-XADS [B1.3]) with ahorizontal coolant flow in thespallation region, mechanicalpumps and a heat sink below thePb free surface level. At roomtemperature the circular target hasan outer diameter of 782 mm: hosting it by replacing 19 S/As,the fuel assembly (FA) wrapper flat to flat external distance is186 mm (191 mm by considering the clearance between FAs).In addition, the spallation module size together with themaximum proton current (20 mA), the selected sub-criticalitylevel (Keff=0.97) and the maximum allowable linear power(PL≅200 [W cm-1]) give as output the core size and the overallpower (Pth).

Figure B1.4a) shows the adopted fuel isotopic composition (Puand MA vectors), which comes from a reprocessed MOX spentfuel, irradiated at 60 GWd t-1 (i.e., 30 years [B1.5]) and after a30–year ageing. The PuO2 and MAO2 were inserted in amagnesium-oxide (MgO) matrix with different volumepercentages in order to flatten the radial performances by using the same fuel enrichment in the wholecore.

Since a high MA content was assumed, particular attention was also devoted to the safety aspects. Byadopting a stochastic approach, it was demonstrated that similar uranium-free fuels, with cross-section vsenergy behaviour similar to that in figure B1.4b), are characterised by:

• “deterioration” of the delayed neutron effective fraction and kinetic parameters;

• lack of Doppler prompt reactivity feedback;

• deterioration of the void effect such that it does not guarantee in any case the desired sub-criticalitylevel.

[B1.3] XADS 41 SNPX 042, Core configuration technical specification of the LBE-cooled XADS, Contractual Deliverable n° D10 FIKW-CT-2001-00179, Technical Report Ansaldo Energia (2001)

[B1.4] Specialist Meetings on the Pb-EFIT core design, INPN Orsay – Paris, 24-25 October 2005; ENEA - Bologna, 22-23 February 2006; CEACadarache, 9-10 March 2006; CEA Cadarache, 13-14 June 2006

[B1.5] G. Rimpault, Definition of the detailed missions of both the Pb-Bi cooled XT-ADS and Pb cooled EFIT and its gas back-up option,Technical Report CEA SPRC/LEDC 05-420 (2005); and IP EUROTRANS – DM1 Design – WP 1.1 – Deliverable 1.1, Contract n° FI6W-CT-2004-516520 (2006) R

efer

ence

s

PuPu238Pu239Pu240Pu241Pu242Pu244

Pu238

Pu239

Pu240

Pu241

Pu242

Pu244

(w%)3.737

46.44634.121

3.84511.8500.001

MA

Np237

Am241

Am242

Am242m

Am243

Cm242

Cm243

Cm244

Cm245

Cm246

Cm247

Cm248

Np237

Am241

Am242

Am242m

Am243

Cm242

Cm243

Cm244

Cm245

Cm246

Cm247

Cm248

(w%)3.884

75.5103.27E-06

0.25416.054

2.37E-200.0663.0011.1390.0890.002

1.01E-04

Pu & MA isotopic compositions

MOX spent fuel after 30 years’ cooling (CEA)

Pu vector Ma vector

91.8% Am

4.3% Cm

a)

Cro

ss s

ectio

n (b

arns

)

105

104

10-4

1000

100

10

1

0.10.01

0.001

Energy (MeV)10-10 10-8 10-6 10-4 10-2 1 100

b)

capture

elastic scattering

fission

Fig. B1.4 – a) Pu and MA vectors; b) capture, elastic

scattering and fission cross sections (from MCNPX code

and JEFF 3.1 neutron cross sections)

B

Fis

sio

n T

echnolo

gy

EFIT two-zone model. A 395-MWthreference core with two radial zones,surrounded by dummy reflector elements inPb (fig. B1.5a)) was designed, and itstransmutation capability and overall coreperformance were checked. To achieve thisconfiguration, while the active height (90 cm,to limit the pressure drop) and the ΔTcore (400-480°C) were maintained fixed, the reactorradial dimension (i.e., the number of FAs) andthe MgO volumetric fraction (VF) were variedto flatten the core radial performance, at thesame time keeping the condition Keff≤0.97over the cycle.

This two-zone solution was analysed by acylindrical geometry model (fig. B1.5b)) inwhich the different radii were assumedequivalent to a certain number of FAs.Neutronic analysis was carried out with theERANOS version 2.0 deterministic code [B1.6]and the ERALIB1 nuclear data library [B1.7].The spatial and energy distributions of theexternal neutron source, generated by thespallation process of the 800-MeV protonsimpinging on the Pb windowless target, wereobtained by Monte Carlo methods (MonteCarlo N-particle transport code [B1.8]). The

angular distribution of the source neutrons was assumed isotropic in the laboratory frame.

The EFIT two-zone model (fig. B1.5) exhibits a suitable radial power distribution by using MgO VFsof 62.5% and 50% (lowest MgO technological content) in the inner (48 FAs) and outer (174 FAs) fuelzones, respectively. Figure B1.6a) shows the geometrical characteristics of the FAs with 168 fuelpins and the 21.65% fuel VF. The 395 MWth power was reached by imposing the max PL (whichreally depends on the MgO VF and the related pellet conductivity) at 213 and 180 [W cm-1] in theinner and outer zones, respectively. Figure B1.6b) shows the power density (PD) radial distributions



330

265

215185170

140

45

15

50

50

90

125

200 252

75

ΔR

ΔR1 ΔR2

Rt = 43.7

Z (cm)

R (cm)

Top assembly

Foot assembly

Boxdummy

Plenum

Plenum

Target

Bea

m li

neIn

tern

al le

ad

Pb

Ext

Fue

l inn

er

Fue

l out

er

b)

0.6

7.2 mm7.52 mm8.72 mm

4.91 mm

0.16

13.63 mm

191 mm

186 mm

178 mm

FuelVoidSSPb

(750°C)

(480°C)(440°C)

VF(Fuel pellet)=21.65%Filling ρ = 0.9167

168+1 Fuel pins(7+1 pin rows)

Fuel inner62.5% MgO

Fuel outer50% MgO

a)

PD

Hom

(W

cm

-3)

R (cm)

115

95

75

55

3540 80 120 160

ffrad=1.29ffax =1.14

ffrad=1.45ffax =1.15

Max INN (BOC)Max OUT (BOC)Max INN (EOC)Max OUT (EOC)

b)

Fig. B1.6 – 395 MWth EFIT two-zone model: a) inner and

outer FA design; b) PD radial profiles at about half active

height (BOC and EOC)

Fig. B1.5 – 395 MWth EFIT two-zone model: a) hexagonal layout; b) cylindrical model

a)


on the homogenised core (at about half of the activeheight where PD reaches maximum values). The orangeand red horizontal lines, which correspond to thetechnological limits on the max PL, indicate that both atthe first and at the second year of irradiation(corresponding to the beginning of cycle [BOC] and endof cycle [EOC]) the safety limits are not exceeded. FigureB1.6b) also shows the radial and axial form factor values(ffrad and ffax), corresponding to the worst condition(BOC, lowest Keff value).

The resulting sub-critical core exhibits very satisfactoryperformance, since it has a very small Keff swing over thecycle limited to about 200 pcm (fig. B1.7a)), requiring aroughly constant proton current that never exceeds16.3 mA.

As for the in-pile fuel cycle, a three-year maximumresidence time was assumed, due to Pb corrosionconstraint. Considering a refuelling pattern of 1/3 of thecore each year, some “ad hoc” hypotheses permitburn–up calculations to be performed without any actualrefuelling, as follows:

• For the core performance it is sufficient to consider the reactor conditions at the first year (BOC) and atthe second year (EOC) of irradiation.

• For the transmutation performance, the third year of irradiation was considered as FA end of life (EOL).

Figure B1.7b) shows the burn-up capability (with the 45.7% fuel enrichment). By considering the massbalances at the third year of irradiation (FA EOL), a relative MA and Pu burn-up of about 13% and 0.25%,respectively, was obtained. The transmutation obtained for the MA and Pu isotopes is 40.6 and0.7 [kg TWhth

-1], respectively, which is almost in agreement with the 42-0 approach.

The main drawback of this two-zone core is the too high ffrad value in the outer part (1.45; fig. B1.6b)): aRELAP thermohydraulic analysis [B1.9] showed that the limit on the maximum cladding temperature(550°C) is reached in this zone. This is a consequence of the small difference between the Pb outlet(480°C) and the maximum cladding temperatures allowed, which imposes working with very limited ffrad.To avoid having a lot of different SA orifices, a core with three radial zones was considered. However themain result is that the 42-0 approach for MA transmutation in a sub-critical system (without Pu burning andproduction) is a viable strategy because the resulting Keff(t) swing (which depends on the fuel enrichment)is compatible with a reasonable proton accelerator current range.

Reactivity worth, decay heat and fuel equilibrium analyses. The uranium-free choice (with high MAcontent) is characterised by a lack of the Doppler effect, a low delayed neutron fraction and deteriorationof the coolant void effect (fig. B1.8a)). These results, obtained by MCNP [B1.8], suggest that some

Ref

eren

ces

[B1.6] G. Rimpault et al., Schema de calcul de reference du formulaire eranos et orientations pour le schema de calcul de projet, CEAXT–SBD–0001 (1997)

[B1.7] E. Fort et al., Application a la realisation de ERALIB1, bibliotheque de donnes neutroniques pour le calcul des systems a spectre rapide,Technical Report CEA SPRC/LEPh 97-002 (1997)

[B1.8] J.S. Hendricks et al., MCNPX Version 2.5.B, LA-UR-02-7086 (2002)

[B1.9] C.D. Fletcher and R.R. Schultz, Relap5/Mod3 Code Manual – User’s Guidelines, Vol. 5, Idaho National Engineering Laboratory;NURG/CR-55 EGG-2596 (1992)

kgK

eff

BOL BOC EOC EOL

0.975

0.973

0.971

0.969

Time (years)

ΔKeff swing

≅ 200 pcm

0 1 2 3

0 1 2 3

3100

2900

2700

2500

Tot PuTot MA

ΔMA/MA (BOL) = -12.95%

ΔPu/Pu (BOL) = -0.25%

a)

b)

Fig. B1.7 – a) Keff(t) behaviour; b) absolute and relative

MAs and Pu burn-up performance

B

Fis

sio

n T

echnolo

gy

neutronic design assumptions as well as the expected core performance should be reconsidered,mainly from the safety viewpoint.

The decay heat problem deriving from the massive use of MAs [B1.10, B1.11] was also studied indetail [B1.4, B1.12]. Compared to the standard MOX fuels, AnOx fuel has a higher decay heat rate,the decay heat decreases less in time and is higher (by up to ∼45 times). Figure B1.8b) showsperformance and behaviour vs decay time for uranium-free fuel. From the reactor design viewpoint,an important aspect is the long-term reliability of the decay-heat-removal components.

Finally the question of core (re)fuelling only by MA fuels, independently of the start-up fuelcomposition, was approached [B1.4]. Preliminary results indicate that whatever the start-up (Pu,MA)O2-x fuel composition, an equilibrium (Pu, MA)O2-x fuel composition, with different Pu/MA ratioand Pu & MA vectors, is reached so that the equilibrium core can be (re)fuelled only by MAs. The"potential reactivity" (or k∞) seems to be sufficient both for the core reactivity and for sustaining BUcycles.

EFIT thermohydraulic and safety analyses. Parallel to the activity for the core design, athermohydraulic numerical model of the EFIT reactor was developed with the system code RELAP5[B1.9]. Besides representing the first step in the dynamic simulation of the sub-critical reactor(coupled thermohydraulic and neutronic) for the safety analyses, the model allowed a preliminaryinvestigation of safety issues in order to confirm the neutronic design. A preliminary layout of theprimary system (fig. B1.9) that implemented all the basic design options for an industrial



Ring

1 2 3 4 5 6Voi

d ef

fect

tota

l rea

ctiv

ityw

orth

per

rin

g (p

cm)

3000

2000

-500

1000

0

Cadarache meetingcore solutionBologna meetingcore solution

a) b)

MOX-origen2

MOX-fispact

30%PU 70% MA-fispact

50%PU 50%MA-fispact

50%PU 50% MA-origen2

30%PU 70% MA-origen2

Abs

olut

e D

H (

W/k

g)

2000

1000

01×10-1 1×103 1×107 1×1091×1051×101

Time (s)

OuterAverage

Core

211

OuterHot

Core

110

InnerAverage

Core

111

InnerHot

Core

SGsTMDP JUN 5

JUN 106

JUN 105 JUN 103

1 (2/3/4)

22

175 171

170

160

112

113

DHR

Pth

161

102

100

120

210

151152153154

281

282283284

181

182183184

Pumps

176 (177/8/9)

82 62

Fig. B1.9 – Schematic of EFIT primary system and RELAP5 nodalization

Fig. B1.8 – a) Coolant void effect; b) absolute decay heat (W/kg) vs time behaviour


transmutator (the use of pure melted lead as coolant,elimination of intermediate loops, installation of heatexchangers and mechanical pumps inside the primary vessel,uranium-free fuel) was simulated starting from the neutronicresults of the EFIT two-zone cylindrical model.

The RELAP5 analyses were used to verify the capability of thethermohydraulic design to support high temperature andpower density and to pass from MOX fuel to uranium-freefuel, both in operational and in accidental conditions. BothDesign Basis and Design Extension Conditions (DBCs andDECs) were considered so as to have a first evaluation of theinherent safety behaviour of the plant. Figure B1.10 shows themain parameter trends for an unprotected loss-of-flowaccident (100% power, natural circulation, full capability ofsteam generators, low capability of decay heat removalsystem, BOC conditions). The results show that a stablenatural circulation capable of limiting cladding, fuel andcoolant temperatures to acceptable values is quickly attained.

A preliminary analysis with the SIMMER-III code of the steam generator tube rupture accident (single andmultiple rupture) was performed for the preliminary design solution [B1.13]. A portion of the EFIT vesselaround the steam generator was modelled, using a simplified cylindrical 2D geometry centred on the tuberupture location. The core structure was schematically represented in the model, and stagnant lead wasconsidered inside the vessel. The results of these calculations show that neither steam explosion effectsnor the risk of void formation inside the core are of concern in the SIMMER-III evaluation.

Electron vs proton accelerator–driven subcritical system performance using TRIGA reactor atpower. In the framework of the RACE project [B1.14] ENEA was concerned with studies on the energeticgain expected in the RACE core. It is assumed that the thermal power dissipated by the W-Cu or uraniumRACE target during the high-power phase will be ~25 kW, which corresponds, according to preliminaryMCNPX calculations on a depleted uranium multi-disk target undergoing a 1.0 mA - 25 MeV electronbeam, to a source strength of ∼6×1013 n/s.

Different MCNPX [B1.15, B1.16] and TRIPOLI4 [B1.17] calculations were performed to analyse thecoupling between a TRIGA (ENEA Casaccia) subcritical core and a photoneutron source and get a firstassessment of the RACE target-core power coupling coefficients (energetic gain) and compare them withthose obtained for the TRIGA Accelerator-Driven Experiment (TRADE) core configurations [B1.18]. Hence,for some calculations it was assumed that an electron beam impinges on a W-Cu target surrounded by

[B1.10] NEA – OECD, Fuels and materials for transmutation. A status report. Nuclear Sci. ISBN 92-64-01066-1, NEA n. 5419, OECD (2005)

[B1.11] IP EUROTRANS, Actions list: decay heat benchmark (2006)

[B1.12] G. Glinatsis, Decay heat investigation on the U-free transmuter cores dedicated fuels, ENEA Internal Report in preparation

[B1.13] H. Yamano et al., Simmer III: a computer program for LMFR core disruptive accident analysis - Version 3.A: Model summary and programdescription, O-arai Engeneering Center - Japan Nuclear Cycle Development Institute (2003)

[B1.14] D. Beller, Overview of the AFCI reactor-accelerator coupling experiments (RACE) project, Presented at the 8th Information ExchangeMeeting on Actinide and Fission Product Partitioning and Transmutation (OECD/NEA) (Las Vegas 2004)

[B1.15] MCNP4C A general Monte Carlo nparticle transport code, J.F. Briesmeister Ed., Los Alamos National Laboratory report, LA-13709- M(2000)

[B1.16] J. S. Hendricks et al., MCNPX, VERSION 2.5.d, LA-UR-03-5916 (2003)

[B1.17] J.P. Both et al., TRIPOLI4, a Monte-Carlo particles transport code. Main features and large scale application in reactor physics, Presentedat the Inter. Conference on Supercomputing in Nuclear Application - SNA’2003 (Paris 2003)

[B1.18] C. Rubbia et al., Nucl. Sci. Eng. 148, 103-123 (2004) Ref

eren

ces

Core power

SG powerCore flow

M/M

0, P

/P0 1×100

6×10-1

2×10-1

0

Core mass flow and power

400 600 800 1000

a)

Tem

pera

ture

(°C

)

1.4×103

1×103

8×102

4×102

Time (s)

400 600 800 1000

Inner core (hot) max temperature

Tlead(hot)

Tclad(hot)

Tfuel(hot)

1429 1400

728

684 619

665

b)

Fig. B1.10 – Unprotected loss-of-flow transient –

RELAP5 main parameters

B

Fis

sio

n T

echnolo

gy

the subcritical Rc-1 TRIGA core. These caseswill be indicated in the following as TRADE-electrons (TRADE-e).

Two core configurations, representative of theSC0 (-500 pcm) and SC2 (-3000 PCM) TRADEconfigurations, were coupled with three types oftarget. The simulations took into accountelectron, photon and neutron transport, usingthe MCNPX code. The material considered wasa W-Cu alloy (75% wt and 25% wt respectively,bulk density 14.7 g/cm3) in two geometrical

shapes: raw cylindrical (h=8.89 cm, r=3.49 cm) andconical (aperture angle 16.5°, h=34.8 cm,rmax=1.5 cm, radial thickness 0.19 cm), as shown infigure B1.11 [B1.19]. A third target type wasrepresented by a set of coaxial disks of depleteduranium with aluminium cladding and water coolant(fig. B1.12). Uranium has the highest photoneutronproduction [B1.20].

Given a fixed electron beam, the neutron source mainlydepends on the target material, but the feasibility of thetarget configuration has to be considered. Some targetconcepts were analysed and the cooling capability ofthe system, choice of materials, thermomechanicalbehaviour and safety issues were discussed.Calculations by MCNPX were performed, mainly toestimate the different neutron sources (besides thepower deposition distribution).

The first target configuration considered was a bare uranium cylinder with r=3.25 cm and h=8 cm.This is not a feasible target solution as, for example, it does not allow proper cooling, but it is usefulfor estimating the maximum achievable neutron yield (some geometrical constraints have to betaken into account since the target is to be placed in the central channel of the core). The secondand third target configurations were based on the conical geometry shown in figure B1.11. Thematerials considered were depleted uranium and tantalum, as for the TRADE target. The thirdconfiguration was a hollow uranium cylinder irradiated by the electron beam in its inner surface,where the power deposition was spread out to allow cooling. The photonuclear reaction data usedfor the MCNPX simulations were the LA150u and the BOFOD libraries, both collected and reportedin the International Atomic Energy Agency (IAEA) photonuclear data library [B1.21].



18

771

348 10720

60

504.7

209.772.7 105.3 83.5

Ø50.8

Ø46

16.493

Ø28.5

Ø15

4.311Ø1.3

7.351

7.351

Ø63

8.578

Ø43

1924

17

Fig. B1.11 – TRADE-like conical shaped target. (dimensions in mm)

6.5 cm

1mm

1.7

mm

20 m

m12 m

m

Tantalum window(thickness=1 mm)

Water(thickness=2 mm)

Aluminium(thickness=1 mm)

Depleted uranium

Fig. B1.12 – Multi-plate target

Fig. B1.13 – UT-NETL core with central

cylindrical uranium target


Some analyses for the 1-MW TRIGA reactor wereperformed at the Nuclear Engineering Teaching Laboratory(NETL) of the University of Texas (UT). The UT-NETL corewas explicitly modelled using MCNP-5 in a coupledelectron/photon/neutron problem. Photonuclear data weretaken from T-16 at the Los Alamos National Laboratory(LANL) and the electron source was a 25-MeV beam with a1-cm–diameter beam spot. A 25-kW beam power and acylindrical uranium target in the central position wereassumed (fig. B1.13).

For the calculations performed by the TRIPOLI4 MonteCarlo code [B1.16], the geometry was a simplified “clean”Texas A&M University (TAMU) TRIGA core (fig. B1.14) havingthe same fuel composition as TRADE. Two coreconfigurations, representative of SC2 (-3000 pcm) and SC3(–5000 pcm) TRADE configurations, were considered, withthe external source located in central core position. Theexternal neutron source was considered to have a spectrumsimilar to that of photoneutrons obtained through electroninteraction with a Pb target of a 20-MeV linear accelerator(linac).

Figures B1.15 and B1.16 show the core power vs thesubcritical level for the different targets taken into account.The results are normalised at 25-kW beam power. Theanalysis shows the requirements for an electron-drivencoupling experiment aimed at providing significant validationelements about the dynamic behaviour of an acceleratordriven system (ADS), in terms both of target performanceand of beam power characteristics. The results show that itis necessary to have a U target in the central position of theTRIGA reactor to obtain a core power greater than 50 kWfor Keff>0.98. Such a minimum power is required to havefeedback effects in the system responses in the presence of source/reactivity transients, as indicated bypreliminary analysis of the influence of thermal reactivity feedback in RACE.

Some results for TAMU TRIGA configurations indicate tighter target/core coupling than in the CasacciaTRIGA RC-1 (TRADE-e), as can be seen by comparing the results in figure B1.16 relative to the same multi-plate target in a central position in TAMU TRIGA and TRADE-e. Further investigations are needed. In anycase, a final check should be performed for the actual core loading that could be envisaged for RACE-HP(high power).

In-core test for the Piccolo-Micromegas neutron detector. One important step needed for approvalof a demonstration device is experimental validation of simulations. Of particular interest is determination

[B1.19] P. Agostini et al., Neutronic and thermo-mechanic calculations for the design of the TRADE spallation target, Presented at the Inter.Conference on Accelerator Applications (Venice 2005)

[B1.20] W.P. Swanson, Radiological safety aspects of the operation of electron linear accelerators, IAEA Technical Report, Series No.188,STI/DOC/010/188 (1979)

[B1.21] Handbook on photonuclear data for applications: cross sections and spectra, IAEA-TECDOC-1178 (2000) Ref

eren

ces

SC2-Keff = 0.96816 SC3-Keff = 0.95037

Cor

e po

wer

(kW

)

100

80

60

40

20

0

Keff

W-Cu cylinder in TRADE

Ta conical in TRADE

W-Cu conical in TRADE

0.95 0.97 0.99

Cor

e po

wer

(kW

)

100

80

60

40

20

0

Keff

0.95 0.97 0.99

U in UT-NETLU multiplate in TAMU

U multiplate in TRADE

U hollow cylinder in TRADE

U conical in TRADE

Fig. B1.14 – Geometrical models

Fig. B1.15 – Core power vs subcritical level for

non–fissile targets (beam power 25 kW)

Fig. B1.16 – Core power vs subcritical level for

uranium targets (beam power 25 kW)

B

Fis

sio

n T

echnolo

gy

of the neutron spectrum (i.e., neutron flux as afunction of neutron energy) for differentconfigurations of the subcritical device. As iswell known, the neutron flux in an ADS consistsof neutrons produced via spallation reactions inthe target and fissions from the multiplyingblanket. Unfortunately neutron spectra cannotbe measured using only one type of detector. Tocover the complete energy range of neutronsproduced, a new neutron detector, namedPiccolo-Micromegas, based on Micromegastechnology has been developed in acooperation with CEA/DAPNIA/SEDI (SaclayFrance) and CNRS/IN2P3 LPC (Caen France).

The principle of Micromegas is based ondetecting the electrons created by ionization ofthe filling gas by charged particles. Operation ofPiccolo-Micromegas as a neutron detectorrequires an appropriate neutron/charged particleconverter, which can be either the filling gas orthe target, with a suitable deposit on theentrance window.

Fissile elements such as 235U, 232Th are usedsimultaneously as neutron/charged particleconverters in addition to 10B and recoil ions ofthe gas (Ar + iC4H10 quencher) filling thedetector. Using four converters with a uniquedetector will permit practically on line extractionof a large range of the neutron flux spectrum ina specific position in the reactor. The largedynamic range of Piccolo-Micromegas willpermit precise measurements and a detailedscanning of the flux into the whole reactorvolume.

At very high counting rate (>100 MHz)measurement will be performed on a currentmode basis. At low counting rate, the fastresponse of the detector will allow the incidentparticles to be counted one by one by means ofa low-noise fast preamplifier. This will open up a

way to measuring the neutron flux at the peripheral part of the reactor and, in some cases, alsowhen full reactor power is not used.

After a first test with the CELINA 14-MeV neutron source at Cadarache, a second test wasperformed with a sealed prototype placed inside the core of the TRIGA reactor at ENEA Casacciain the configuration shown in figure B1.17. The detector was placed inside a long sealed stainlesstube having the same dimensions as the empty reactor rod. The usual BNC (fig. B1.18a)) cables



Neutron/charged particle converter

35 m

m

Th-232

B-10

HV1

HV1

HV2

HV2

P1P1

P2P2 P3

P3

P4

P4

U-235

Pads

Micromesh

Ceramic insulator

Ar+ (2%) Iso-butane (1 bar)

3 mm

20 mm

160μ

m1m

m

b)

Fig. B1.17 – a) Piccolo-Micromegas assembly used in

1–MW TRIGA Casaccia reactor test; b) schematic of the

principle of Piccolo-Micromegas detector (in horizontal

position) for neutron flux measurement

Fig. B1.18 – a) The six BNC cables; b) Piccolo-

Micromegas assembly inside the TRIGA reactor

a)

Detector


were used and placed inside a10-m watertight stainless tube(fig. B1.18b)).

Piccolo-Micromegas hasworked at different reactorpowers from 10 W to 400 kWat two different positions insidethe reactor: on the periphery(fig. B1.19) and in the middle(fig. B1.20). At low power,measurements were per -formed by simple counting onthe pads; at higher power, onlythe high-voltage current canbe registered as the countingrate is too high. Thisexperiment is aimed atstudying the behaviour of thedetector inside a nuclearreactor. Several topics havebeen tackled, such asresponse linearity vs thereactor power or ageing. Theoutput energy spectra corresponding to the different converters have been also studied to get a thoroughunderstanding of the detector response.

An example of the results is shown in figure B1.21, which shows clearly that the new Piccolo-Micromegascan work in a nuclear reactor, which is a very aggressive experimental condition.

Interaction of lead alloys with water. The aim of the experimental campaign is to assess the physicaleffects and possible consequences of interaction between LBE and the water from large leaks caused bya cooling-tube rupture inside the steam generator of a reactor such as XT-ADS or EFIT and to provide datafor validation of the mathematical modelling.

The relevant parameters for the tests were selected according to the XT-ADS reference design. TheSIMMER code was adopted to simulate the experiments for the modelling activity. The ex LIFUS5 plant(fig. B1.22), designed and constructed to simulate this kind of interaction in a wide range of conditions(e.g., pressure up to 200 bar, temperature up to 500°C) was refurbished and re-arranged for theexperiments.

For Test n.1 (fig. B1.23), successfully carried out in March 2006, pressurized water was injected at 70 barinto the reaction vessel containing LBE at 350°C. The most important of the experimental results(fig. B1.23) in terms of pressure evolution in the reaction system is that a maximum value (78 bar) higher

Configuration 250

FuelGraphitePiccolo MicromegasSourceRegulating rodsShim 1 and 2 andsafety rodIrradiation facilityRabbit

Configuration 250

FuelGraphitePiccolo MicromegasSourceRegulating rodsShim 1 and 2 andsafety rodIrradiation facilityRabbit

Fig. B1.19 – Position of Piccolo-Micromegas in the

periphery of the TRIGA reactor core

Fig. B1.20 – Position of Piccolo-Micromegas in the middle

of the TRIGA reactor core

Cur

rent

s (n

A)

Cou

nts/

100

s

Reactor power (kW)

Reactor power (kW)

6000

4000

2000

00 100 200 300 400

0 100 200 300 400

1×106

9×105

7×105

5×105

3×105

1×105

0

H recoil

B-10

U-235

C4 (Th)

Th-FF counts per 100 s vs reactor power

Fig. B1.21 – Currents vs reactor power and fission fragment counts from 232Th vs

reactor power

B

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than the water injection pressure (70 bar) wasreached in the reaction-expansion vessel of LIFUS5during the test. This means that it is fundamental toadopt suitable and reliable countermeasures in orderto avoid such pressure peaks in the reactor pool.

Integral Circulation Experiment activities. In theframework of the Domain DEMETRA, ENEA isstrongly involved in the “Large-Scale Integral Test”work package and is committed to performing anintegral experiment with the aim of reproducing theprimary flow path of the European TransmutationDemonstrator (ETD) pool nuclear reactor, cooled byLBE.

In 2006, ENEA worked on the design of a new testsection (fig B1.24) to install in the CIRCE facility atENEA Brasimone for the Integral CirculationExperiment (ICE). To achieve the goals of the integraltest, a high thermal performance heat source (HS)was required. The ICE heat source, consisting of apin bundle made up of electrical heaters with a total thermal power of 800 kW, was designed toachieve a ΔTHS/Lact value of 100°C/m, a pin power density of 500 W/cm3 and an average liquid



V10

V16

V12

V2 LT2

GS1

V1

V3

V4

V5

V9D2

V7TC

TC

TC

TCS2H2O

H23”

H2

H23”

TC

SP

S5

PT7

PT5

PT3

PT1

PT9

PT10

PT11

DPT1TC3

TC2

PT2-4

TC1-30

PT6-8

V14

V11

GS2 DrainageTo vacuum

pump

V8

V6 V15

V13

D1 FA

1/2”1/2”

Al 1” Al 3”Al 10

Al 1/2”

Wa 1/2”

S3

S4

S1

Pb-17Li

Pb-17Li

S1

S5

Time (ms)

Pre

ssur

e (b

ar)

0

20

40

60

80

1000 2000 30000

Fig. B1.22 – P&I of LIFUS5 plant

Fig. B1.23 – Results of Test n.1

Deadvolume

Fuel pinsimulator

Flow meter

Riser

Fittingvolume

Heatexchanger

CIRCE vessel

Fig. B1.24 – ICE test section


metal velocity of 1 m/s, in accordance with thereference value adopted for the ETD concepts (XT-ADS, EFIT). A pin bundle was chosen to simulatethe HS in order to improve cooling of the heatersand avoid overheating of the cladding material. TheHS was coupled to the test section by a suitablemechanical structure, designed by ENEA. Theheaters and the mechanical structure whichsurrounds them make up the so-called fuel pinsimulator (FPS). The main experimental para meterscharacterising the heat source (fig. B1.25) and ICEactivity are reported in table B1.I.

A gas lift pumping system successfully tested andqualified during previous ex perimental campaignsin CIRCE is used to perform the ICE activity. A pressure head of 40 kPa is available to promote the LBEcirculation along the flow path.

The ICE test matrix has been defined, with the following tests foreseen:

• Steady-state circulation: isothermal condition, LBE average temperature of 350°C, no power supply.The aim is to get fluid-dynamics characterisation of the test section.

• Steady-state circulation: LBE average temperature of 350°C, full thermal power. The aim is to evaluatethe coupling of the HS and heat exchanger (HX) and analyse the thermal hydraulic behaviour of a heavyliquid metal (HLM) pool system primary loop.

• Transient condition: loss of cold sink, starting from the nominal condition. The aim is evaluate the trendof the average temperature through the HS and HX.

• Transient condition: loss of pumping system, starting from the nominal condition. The aim is analyse thetransition from forced to natural circulation and characterise the natural circulation flow regime in a HLMpool system.

An appropriate cold sink was designed. Consisting of a prototypical LBE-pressurized water shell heat

XT-ADS EFIT ICE

Coolant LBE Pure lead LBE

Primary loop circulation Mechanical pump Mechanical pump Gas lift technique

Fuel assembly lattice Hexagonal Hexagonal Hexagonal

Fuel assembly type Wrapper Wrapper Wrapper

Fuel assembly spacer Grid Grid Grid

Fuel pin diameter (D) [mm] 6.55 8.72 8.2

Pitch to diameter ratio (p/D) 1.41 1.56 1.8

Fuel heat flux q’’ [W/cm2] 85-115 100-140 100

Fuel power density q’’’ [W/cm3] 500-700 450-650 488

Average velocity fuel pin region [m/s] 1 1 1

Fuel pin active length [mm] 600 900 1000

Tin/tout core [°C] 300/400 400/480 300/400

ΔTHS/Lact [°C/m] 167 88 100

Fuel pin cladding material T91 T91 AISI 316L

Secondary coolant Low pressure Water with Pressurizedboiling water superheated water

steam

Table B1.I – Overview of the experimental parameters adopted for the ICE activity,compared with the ETD concepts foreseen

Fuel pins simulated by electrical heaters

Assembly HexagonalDiameter 8.2 mmPitch/diam. 1.8Active length 1000 mmActive pins 31Total pins 37

h

pFuel heat flux: 100 W/cm2

Thermal power pin: 26 kW

Fig. B1.25 – ICE heating section

B

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gy

exchanger made up of a seamlessU–tube, it will be placed in the upperplenum of the main vessel (fig. B1.26).The possibility of installing and testingdifferent prototypical HXs (i.e., helicaltubes) is under evaluation. In any casethe opportunity of adopting pressurizedwater as a secondary fluid has to beconfirmed by the currently ongoingsafety analysis.

VELLA - Virtual European Lead Laboratory

ENEA is responsible for coordinating the Virtual European Lead Laboratory (VELLA), which is an FP6integrated infrastructure initiative started in October 2006. The ambitious intent to homogeniseEuropean research in the field of lead technologies for nuclear applications thereby producing acommon platform of work suggested dividing VELLA into Networking Activities (NAs), TransnationalAccess Activities (TAs) and Joint Research Activities (JRAs). The objectives of the NAs is to createa wide “virtual" community of researchers, define common standards and protocols for the use ofthe facilities and interact with other programmes and institutes operating in this field. The TAobjectives are to promote access by researchers, universities and companies to currentinfrastructures and knowledge in order to increase the competitiveness of European industry. TheTAs would also provide a framework for training young researchers to use the EU infrastructuresduring the three years of the project and for promoting mobility between the partners and thelaboratories of the consortium. Finally, the JRA goals are to improve current knowledge on leadtechnologies, develop and operate heavy liquid metal (HLM) components and instrumentation,especially in a neutron irradiation environment and, finally, study HLM thermal hydraulics.

ENEA, as coordinator, is involved in all the NAs, provides access to the infrastructures andparticipates in three of the four JRAs.

In 2006 efforts were mainly devoted to management activities in order to rationally organise the workto be carried out. The management structure of VELLA was approved and the technical andscientific committees responsible for managing the JRAs and the access to infrastructures were setup. The activities to be performed in the framework of the JRAs were planned in detail and anappropriate quality control system established. ENEA’s activities also included financialmanagement. A lot of work was also devoted to creating the “virtual” community, by constructingan official web-site [B1.22], intended to become a central point of information on HLM technologies.

B1.2 Evolutionary and Innovative Reactors

The main issue in this field in 2006 was the definition and launching of a three-year R&D nationalprogramme based on “strategic funding devoted to the National Electric System R&D” andfocussed on participation in international initiatives such as the International Near-Term Deployment(INTD) and Generation-IV Nuclear Systems. The programme is being managed through a specificagreement between the Italian Ministry of Economic Development and ENEA, with the jointinvolvement of major national organisations still active in the nuclear sector, i.e., Ansaldo Nucleare,Ansaldo Camozzi, Del Fungo Giera Energia, Italian Universities Consortium for Research in NuclearTechnologies (CIRTEN) and SIET (an ENEA subsidiary SME). The total funds for the first year amountto 5.5 MEuro and comparable annual funds are expected for the rest of the programme. The maingoals of the programme are to



Assembly: TriangularTubes: “U” - shapeNum. tubes: 13(3/4”)Material: T91Pressure: 6 barΔT: 30°CFlow rate: 6.5 kg/sVelocity: 1.5 m/sMax ΔT wall: 285°C

Tube side

Fig. B1.26 – ICE heat exchanger


Ref

eren

ces

• keep open the future nuclear energy option in the country;

• contribute to the development of innovative nuclear systems which promise to be “sustainable”,acceptable by the public and economically interesting;

• sustain the growth of the necessary competences through participation in promising projects with solidfoundations;

• support the effort required by national industry to keep up with the pace at world and domestic level.

In particular, the national R&D programme supports experimental and analytical activities for the furtherdevelopment of the GENIII+ International Reactor Innovative and Secure (IRIS) and GENIV Lead-CooledFast Reactor (LFR) as well as some technological activities as support to the GENIV Very High TemperatureReactor (VHTR) and to the GENIII AP1000 reactor.

This national programme is also intended to be synergic and coherent with the Generation-IV initiative aswell as with a number of the Sixth European Framework Programme (FP6) projects: the European Lead-Cooled System (ELSY), coordinated by Ansaldo Nucleare; the Reactor for Process Heat, Hydrogen andElectricity Generation (RAPHAEL); Roadmap for a European Innovative Sodium Cooled Fast Reactor(EISOFAR); Assessment of Liquid Salts for Innovative Applications (ALISIA).

ENEA also participates in the “Coordination Action” Sustainable Nuclear Fission Technology Platform (CASNF-TP), which is in charge of developing a coherent European strategy onnuclear fission and consolidating the European and Euratom positionwithin the GIF initiative and in the linked Coordination ActionPartitioning and Transmutation European Roadmap forSustainable Nuclear Energy (PATEROS), aimed at “deliveringa European vision for the deployment of the partitioning andtransmutation technology up to the scale level of pilotplants for all its components”.

The following is a short summary of the main resultsachieved over 2006 with reference to the innovativenuclear systems developed within the above-mentioned programmes and projects.

International Reactor Innovative and Secure

IRIS (fig. B1.27) is designed as an advanced, modularsmall-medium reactor. It is an integral-type pressurized-water reactor with a power level of 335 MWe, featuring anintegral primary system configuration with all the maincomponents (reactor coolant pumps, steam generators, pressurizer,control rod drive mechanisms) located within the reactor vessel. Thisconfiguration enables a simplified design with enhanced reliability and economics and supports its safety-by-design™ approach, which results in exceptional safety characteristics. In addition to electricity-onlyproduction, IRIS is also well suited for cogeneration, including water desalination, district heating, andprocess steam generation.

Furthermore, IRIS well fits the recently announced US Department of Energy initiative - Global NuclearEnergy Partnership (GNEP) - aimed at supporting worldwide expansion of the use of nuclear energy in aresponsible and proliferation-resistant way. Within the GNEP framework, IRIS can - in the near term - offeran advanced reactor design to satisfy the need for smaller, grid-appropriate reactors.

[B1.22] www.3i-vella.eu.

Dry wellcontainment

Suppressionpools

Fig. B1.27 – The IRIS reactor

B

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sio

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gy IRIS is being developed by an international team, led

by Westinghouse, incorporating organisations fromten countries, including Italy (ENEA, CIRTEN,Ansaldo Nucleare, Ansaldo Camozzi and SIET). Thepreliminary design has been completed and thetesting needed for design certification just started in2006. The centrepiece of the testing programme isthe integral system testing to be performed at theSIET facility in Italy. Since mid-2006, a multinationalgroup of experts coordinated by Westinghouse andENEA has been designing the SPES-3 experimentalfacility, devoted to an integral testing campaign forthe IRIS reactor licensing process. The advancedsafety features of the IRIS reactor require a uniquetest facility, where both the containment system andthe primary system are simulated (fig. B1.28).Moreover, the scaling approach suggested theadoption of an integral layout for the facility as well.The SPES-3 integral test facility to be built at theSIET labs is a full height, full pressure andtemperature, scaled volume facility (1:100 powerand volume ratio). The main components, i.e., thehelical coil steam generators, the core bundlesimulator, the pressurizer, are integrated in the tallreactor pressure vessel as in the IRIS design. Thefacility is designed both for integral testing and forseparate effect tests. A “simulation group” has beenset up to support both the design of the facility andthe pre-test and post-test analyses. Both best-estimate system codes (RELAP, GOTHIC) and CFDcodes (Fluent) are adopted.

European Lead-CooledFast System

The ELSY reference design(fig. B1.29) is a 600–MWepool-type fast reactor cooledby pure lead. This concept hasbeen under development sinceSeptember 2006 and issponsored by the EuratomFP6. The ELSY project,coordinated by AnsaldoNucleare, is being performedby a consortium consisting oftwenty organisations includingENEA, CIRTEN and CESIRicerca from Italy. ELSY aimsto demonstrate the possibility



Containment

Long termgravity makeupsystem

Emergencyborationtanks

Integral reactorpressure vessel

Pressuresuppressionpools

Reactor cavity

Primary pump

Fig. B1.28 – Sketch of the SPES-3 integral testing facility

Fig. B1.29 – Sketch of ELSY reactor block

Pb

B4C rods(36 As)

Fuel outer(54 FAs;Epu=23.8%)

Fuel intermediate(90 FAs;Epu=18.9%)

Fuel inner(109 FAs;Epu=15.6%)

Fig. B1.30 – The open square

lattice ELSY core


of designing a competitiveand safe fast critical reactorusing simple engineeredtechnical features, whilstfully comply ing with theGeneration-IV goal of MAburning capability.

The activities carried out in2006 were mainly devotedto defining requirements,selecting options and verifying critical issues. The requirements reflect the GEN IV goals of sustain ability,economics, safety, proliferation-resistant and physical protection. Sustainability is the leading criterion forcore design, which focusses on demonstrating the potential of the reactor to be self-sustaining inplutonium and to burn its own generated MAs. Two different core configurations are being studied:wrapperless assemblies in a square lattice where pins are arranged in square bundles as well (fig. B1.30),or more conventional wrapped assemblies in a hexagonal lattice. Both the concepts assume the samethermal power (1500 MWth), fuel (MOX), fuel residence time (5 years), BU (100 MWd/kgHM for the hottestassembly), cladding (T 91 with a maximum allowable temperature of 550°C), cladding radiation damage(100 DpA), inlet (400°C) and outlet (480°C) core temperature. The comparison focusses on conversionfactor and MA burning capability (sustainability); core dimensions, loading factor, fuel inventory, peak andaverage power density (economics); coolant velocity (on which corrosion and natural circulation depend),control-rod system, coolant void/density effect and reactivity coefficients (safety); use or not of axialblankets (proliferation).

In order to provide the core design with some boundary conditions, a preliminary T/H analysis of the fuelrod was also performed with the RELAP5 code. The parameter-set for open square SA in table B1.II wasfixed on the basis of engineering considerations, previous LFR designs and current knowledge on leadtechnology. As the cladding temperature is consideredthe most critical parameter to meet safety requirementsin heavy liquid metal (HLM) reactors, aluminized T91steel was selected as cladding material to increase thesafety limit in operating conditions (Tclad < 550 °C).Preliminary parametric calculations alloweddetermination of the maximum admissible linear powerto meet such a limit; the result was a maximum formfactor of the radial power distribution of 1.2 (fig. B1.31).However, this preliminary evaluation could be tooconservative. Indeed, applying different empiricalcorrelations from the literature for single-phase heattransfer in lead and LBE, the corresponding claddingtemperature distributions are pretty different(fig. B1.32). In short, the correlations recently derivedfor rod bundle geometry abate the heat transferresistance and may be beneficial for the design of anLFR. For instance, using the Zhukov’ correlation(developed in the framework of the BREST reactor), thecladding peak temperature (red or brown line) is about40°C lower than the value calculated with thecorrelation implemented in the RELAP code(yellow line).

Concerning lead technology, ENEA coordinates all theactivities to be performed in the work package anddedicates a strong effort to investigating the physical

Thermal power 1500 MW # FA 240

Av. linear power 200 W/cm FA Square 17x17

Inlet temperature 400 °C Power/FA 6.25 MW

Outlet temperature 480 °C Axial shape factor 1.16

Total mass flow 126157 kg/s D fuel pellet 7.14 mm

D pin 8.5 mm Gap thickness 0.115 mm

Pitch 13.6 mm Clad thickness 0.565 mm

H active fuel 1100 mm

Table B1.II – Design parameters for LFR square open SA

Radial shape factor

Acceptable clad max temp=550°C

0.9 1.1 1.3 1.5

Tem

pera

ture

(°C

) 580

560

540

520

Ele

vatio

n (m

)

1.0

0.8

0.6

0.4

0.2

0

Temperature (°C)380 420 460 500 540 580

Lead temperatureBorishanskiGraberCalamaiZhukov (no spacers)Zhukov (spacers)SubbotinKirillov-StromquistLubarsky“clean”“dirty”

Fig. B1.31 – Peak cladding temperature at different

radial shape factors

Fig. B1.32 – Effect of the different correlations on the

peak cladding temperature

B

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and chemical properties of lead and its interaction with the structural materials and the secondarycoolant, as well as evaluating corrosion protection-coatings and corrosion-resistant steels forcladding, pump impellers, etc.

Following a critical review of the collection of existing data on lead thermophysical properties carriedout by ENEA, Bologna University and the Belgian Nuclear Research Centre (SCK-CEN), a consistentdatabase on the design-relevant properties is being compiled.

ENEA’s experience in LBE technology has been invaluable in extrapolating the technologicalsolutions (technologies, components, instrumentation) developed for lead bismuth to pure lead. Inaddition, ENEA has contribut ed, with its knowledge on purification, to a critical review of LBEproperties and has participated in the collection of information on the oxygen control system (OCS),instrumenta tion and procedures (filling, draining, component removal).

Very high temperature reactor

In consideration of the helium loop (HE-FUS3) available at ENEA Brasimone plus past experience inthe relative modelling, ENEA became a partner in the Reactor for Process Heat, Hydrogen andElectricity Generation (RAPHAEL) Consortium in May 2006. RAPHAEL, coordinated by AREVA NPSAS France, is an FP6 Integrated Project aimed at developing technologies for gas systems withtemperatures ranging between 850 and 1000°C.

ENEA’s contribution concerns three sub-projects: coupled reactor physics and core thermo-fluiddynamics, component development and safety. In particular, ENEA will test a prototypical heatexchanger (HEATRIC mockup) with helium at the primary and secondary sides in the HE-FUS3facility (fig. B1.33). The main experimental conditions will reproduce the operating conditionsexpected for the component: pressure 2.4 MPa and He flow rate 0.0475 kg/s in both sides, I/Otemperatures 508-127°C in the primary side and 108-488°C in the secondary side. Theexperimental data from the tests at HE-FUS3 (several steady states and two loss of flow [LOFA]transients (fig. B1.34) in a wide range of working conditions) will be used in a benchmark exercisefor validation of the thermal-hydraulics system transient codes.



HEATRICVACUUM

FV261

FV231

HV289 HV2

FV213

FV235FV5

FV6

FV4

E214ECONOMIZER

FV234

FV1

FV7

BY-PASS

FV23ø

HV25ø

E24øCOOLER

S26øFILTER

PSV2ø8

V2ø5TANK

PSE2ø9

FV1øK2øK2ø

COMPRESSOR

HV3øHV3ø

HV251

HV252E219/1HEATER

E219/2HEATER

E219/3HEATER

FT228

PSE257

PSV268PSV269

L264MIXER

PSE265

L263MIXER

FV262INOUT

GASANALYSIS

COLD

TEST SECTION

PURIFICATIONIN

VACUUM

HELIUMDISCHARGE

SYSPCV248

FT212

FV249

FV9

FV8

PURIFICATION OUT

PCV246

PCV246 FV247PRV244

HV243HELIUMFILLING

SYSHE BOTTLES

Fig. B1.33 – HE-FUS3 facility with HEATRIC

mockup


Finally, in order to provide experimental datafor the validation of neutronics deterministiccodes, ENEA will perform benchmarkexperiments in the fast source reactorTAPIRO of ENEA Casaccia. Theseexperiments will make it possible toreproduce the strong changes in the neutron spectrum at the interface core/reflector, peculiar to high-temperature gas reactor (HTGR) systems.

B1.3 Nuclear Safety

Nuclear safety studies are performed in the framework of international programmes. During 2006 theactivities addressed code validation and accident analysis, severe accidents, and reliability and riskanalysis.

Code validation and accident analysis

Mainly performed within a bilateral agreement funded bythe French Institute for Radioprotection and Nuclear Safety(IRSN), the activities are summarised in the following.

Analysis of the BETHSY experiment 4.3b. The CESARthermal-hydraulic module of the Accident Source TermEvaluation Code (ASTEC) V1 was validated againstexperiment 4.3b at the CEA Grenoble BETHSY facility,which simulates a multiple steam generator tube rupture ina French PWR-900 reactor.

Comparison of the CESAR results with experimental dataconfirms the capability of the code to well simulateaccident situations in such reactors and, in general, thetest parameters and phenomena are well reproduced. Inparticular, a) the depressurization rate of the primary andsecondary sides is well calculated by the code(fig. B1.35); b) in both test and calculation the restart ofthe primary pump is effective in recovering the circulationin the secondary side, leading to a rapid depressurizationtowards stable and safe conditions; and c) the appearanceand disappearance of stratification phenomena in thesecondary side of the broken steam generator are wellreproduced by the code (fig. B1.36).

PWR-1300 H3 sequence analysis. A severe accidentsequence resulting from a station blackout with totalunavailability of auxiliary and safety systems after reactorscram in a French PWR-1300 plant was calculated withthe integral ASTEC V1.2 up to core relocation and vesselrupture. The ASTEC results before core degradation takesplace were compared with the results of the samesequence calculated with CATHARE2 V2.5 code in order

Mas

s flo

w r

ate

(kg/

h)

Tem

pera

ture

(°C

)

600

500

400

300

800

600

400

2000 40 80 120 160 200

Time (s)

Fig. B1.34 – LOFA transient – test section temperature

at different positions and mass flow rate

Pre

ssur

e (P

a)

Time (s)0 8000 16000

1.6×107

1.2×107

8.0×106

4.0×106

0

Break opening

Spray on

Slow cooldownPump 2restartRapid

cooldown

Tem

pera

ture

(K

)

Time (s)

Break flow reverses

0 4000 8000 12000 16000

560

540

520

500

Fig. B1.36 – Steam generator riser wall temperature (solid

line) at different heights compared with experimental data

(dots)

Fig. B1.35 – Primary and secondary pressure (solid lines)

compared with experimental data (dots)

B

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sio

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echnolo

gy to highlight the differences between the two

codes.

In spite of some discrepancies in the initialphase, the time evolution of the main thermal-hydraulic parameters of the primary andsecondary systems calculated by ASTEC is, ingeneral, similar to that calculated byCATHARE2. The largest discrepancy was foundin the pressurizer safety valve operationmodelling (fig. B1.37), which is much moresimplified in ASTEC than in CATHARE2.

In-vessel core melt progression and hydrogengeneration were evaluated with the DIVAdegradation module of ASTEC until coriumrelocation in the lower plenum and lower headvessel failure (fig. B1.38). A sensitivity study onmore uncertain core degradation parametershighlighted their importance for in-vessel coremelt progression and hydrogen release. Inparticular, in the fuel rod candling process,relocation parameters, such as velocity andminimal liquid fraction for the beginning of flowdown, may notably affect the timing andamount of corium relocated in the lower headand the in-vessel hydrogen mass produced.

QUENCH-11 post-test analysis. The boil-off QUENCH-11 experiment conducted atForschungszentrum Karlsruhe (FZK) was analysed with the ICARE/CATHARE code. At first, thecalculation was performed with the ICARE2 code in stand-alone mode for the participation in thesemi-blind QUENCH-11 benchmark promoted by the European Commission within the SevereAccident Research Network (SARNET) project. Afterwards, the post-test analysis was carried outusing the more recent coupled version V2 of ICARE/CATHARE.



Flo

w r

ate

(kg/

s)

120

80

40

0

Time (s)6000 10000 14000

Qvap CATHARE

Qliq CATHARE

Qvap ASTEC

Qliq ASTECFig. B1.37 – Pressurizer safety valve mass flow rate

(ASTEC – CATHARE result comparison)

3000

2000

1000

2500

1500

600

4.74

2.94

1.14

-0.657

-2.45-3.6 3.6-1.8 1.80

H(m

)

T(K

)

R(m)

Fig. B1.38 – Core melt relocation at transient end

(ASTEC code result)

Tem

pera

ture

(K

)

2000

1400

800

200

Time (s)0 2000 4000 6000

Boil-off phase

RefloodTFS 2/11TFS 5/11Tc3_75cm (icare2)Tc3_75cm (IC_v2)

Flo

w r

ate

(kg/

s)

0.0015

0.0009

0.0003

0

Time (s)5400 5600 5800 6000

Fig. B1.39 – Clad temperature at 0.75 m elevation Fig. B1.40 – Hydrogen generation during reflood

ICARE 2 (green line), IC V2 (blue line), est. (red line)


The ICARE2 and ICARE/CATHARE V2 codes were successfully applied in the post-test analysis ofQUENCH-11. Code-to-code result differences, depending on the thermal-hydraulic model used, werepointed out and explained against experimental data. In spite of some deviations in the prediction of theinitial boiling rate and collapsed water level, in general, both codes simulate quite well the boil-off phase(fig. B1.39). Both codes are also able to predict the large amount of hydrogen measured during reflood(fig. B1.40): ICARE2 well predicts the total mass of hydrogen produced, but the timing of hydrogengeneration is notably delayed; whereas ICARE/CATHARE V2 predicts the timing of hydrogen release betterthan ICARE2, but it underestimates the total hydrogen production. Finally, the sensitivity analysis withICARE/CATHARE V2 on some significant and uncertain code model parameters has highlighted theimportance of some code model parameters relative to hydrogen generation during reflood.

Spent fuel pool uncovery accident analysis. The consequences of an uncovery accident in anirradiated fuel assembly during unload operations in the pool of the spent fuel building was simulated withthe ICARE/CATHARE code considering progressive pool draining, which is a more realistic scenario thanthe instantaneous draining studied in 2005.

Two models were developed to simulate a water level decrease equal to 12.5 cm/min. One ("true draining")considers that the system is initially filled with water and the progressive level decrease is obtained byimposing as boundary condition a decrease in the pressure difference between the top and bottom of thefuel assembly. The other ("water level simulated") takes into account the effects of the level decrease onthe fuel assembly and imposes a boundary condition on the surface of the fuel rods, which reproduces thethermal transfer between the fuel rods and the water of the system (axial profile of the exchange coefficientas a function of time).

The two models give very similar results. Figure B1.41 shows the axial temperature profiles in the fuelassembly calculated with the two models during pool draining, 1000 s after the beginning of the accident.The water level (true or simulated) is indicated by the arrow. The fuel assembly is completely uncoveredafter 1850 s and the first temperatureescalation, driven by Zircaloy oxidationunder air atmosphere, occurs in the lowerpart of the fuel assembly at around 1 m oflevel, after about 4000 s of transient.

It is worth noting that minor code“adjustments” to the calculations werenecessary with the true draining model inorder to obtain physical results during thewater level decrease. In particular, the lackof a stratification model led to an erroneouscalculation of the heat transfer between thestructures and the fluid and, within the fluid,between the liquid and the gas phase.Modification of the dry-out criterion wasnecessary to avoid non-physical behaviour.

Severe accident analysis

The severe-accident studies in progress within the SARNET project dealt with the following topics during2006:

LOFT LP-FP-2 experiment analysis. The LP-FP-2 test, performed in the Loss-of Fluid Test (LOFT)facility at the Idaho National Engineering Laboratory (INEL) USA to provide information on fuel rodbehaviour, hydrogen generation, and fission-product release during a loss-of-coolant accident scenario ina pressurized water reactor (PWR) up to core reflood, was analysed with ASTEC V1 to assess the abilityof the code to simulate thermal-hydraulic conditions and core degradation phenomena. The ASTEC resultswere then compared with the results of the ICARE/CATHARE code.

Tem

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(°C

)

Row 1 (true draining)Row 1 (water level simulated)Row 2 (true draining)Row 2 (water level simulated)Row 3 (true draining)Row 3 (water level simulated)Row 4 (true draining)Row 4 (water level simulated)Row 5 (true draining)Row 5 (water level simulated)

400

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Elevation (m)0 1 2 3 4

Fig. B1.41 – Temperature axial profiles 1000 s after the accident

beginning

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ASTEC simulates reasonably well the transient phase of the experiment before the reflood phase,that is, reactor system thermal-hydraulics, core uncovery and heatup, hydrogen generation andfission-product release. The total hydrogen release is in good agreement with test measurements.Instead the code needs some improvement in order to investigate the reflood phase becausetemperature excursions and consequent heavy degradation of the fuel rods, hydrogen release andprimary pressure increase are not reproduced by ASTEC because of the inadequate modelling.

In general, the ICARE/CATHARE results confirm the validity of the ASTEC results.

MOZART experiment analysis. A preliminary comparison between the air oxidation modelactually implemented in the ICARE2 code that simulates the reaction kinetics between zircaloy andoxygen with a parabolic law and the first isothermal experiments carried out in the MOZART facilityby IRSN and related to zircaloy-4 non-oxidized samples in the temperature range 800 to 1000°Cwas performed for Work-Package WP9-3 (zircaloy oxidation by air and steam-air mixture).

Figure B1.42 shows calculated and measured (thermo-balance) mass gain vs time, at four differenttemperatures (800, 900, 950 and 1000°C). The experimental data exhibit parabolic behaviour for avery short time (roughly 30 min at 800°C). During this period, the calculated mass gain is

overestimated, except at1000°C. At thistemperature, theexperimental protocol(iso thermal con ditions)cannot be completelymet because theoxidation powerproduces a not negligibletemperature peak at thebeginning of the test.After the loss of parabolicbehaviour (post break-away period), experi -mental data indicate acontinuous increase inthe oxidation kinetics andthe code model becomes

totally inadequate to predict the mass gain (underestimation of the reaction kinetics).

The model limitations in the simulation of post break-away oxidation may be more or less important,depending on the expected temperature evolution during accidental transients. However animprovement in the code model to take into account the post break-away behaviour is necessaryto simulate uncovery accidents in the spent fuel pool, as the temperature increases gradually andmost oxidation occurs in the post break-away kinetics regime.

ASTEC reactor application and benchmarking. The work carried out in 2006 concerned a)benchmarking of ASTEC V1.2 R1 and MELCOR 1.8.6. based on the accident reactor sequence H2and b) identification of the most critical parameters and variables influencing the code response,mainly for in-vessel processes. This activity was shared with AREVA-NP SAS and IRSN. AREVAused the MAAP code for benchmark and successive comparisons.

Details explaining the differences that emerged during model comparison are briefly reported. Themain difference was found in some corium processes, mainly in candling. The candling model in theMELCOR “COR” package is semi-mechanistic and refers to the downward flow of molten corematerials and subsequent refreezing of these materials as they transfer latent heat to coolerstructures below. ASTEC uses a different model and so some differences are now clearlyunderstood.



Mas

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Time (min)

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101 10 100 1000

MOZART test 44 (800°C)MOZART test 45 (800°C)ICA/CATH (800°C)

MOZART test 34 (950°C)ICA/CATH (950°C)MOZART test 39 (900°C)MOZART test 40 (900°C)ICA/CATH (900°C)

MOZART test 29 (1000°C)MOZART test 30 (1000°C)MOZART test 31 (1000°C)ICA/CATH (1000°C)MOZART test 33 (950°C)

Fig. B1.42 – Measured and calculated O2 mass gain


Ref

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Concerning hydrogen production, at the moment there are still some unexplained questions. There are notnegligible gaps between the results provided by the codes involved in the benchmark. Very recently ENEAmade a simple comparison referring to the table with the timing of the main events of accident sequenceH2 and found very strong differences between new and old MAAP calculations, between ENEA-ASTECand AREVA-ASTEC calculations and between the latest MELCOR and MAAP calculations. Probably MAAPand MELCOR users followed completely different approaches in modelling the main processes occurringduring corium production and mass relocation; perhaps they used different values in the mostrepresentative coefficients governing some relevant equations.

Concerning the water inventory strong differences were found for water in the primary and secondarycircuits given by ASTEC and MELCOR calculations, due to a totally different approach of calculation insidethe codes. So far, code benchmarks have been performed without well-defined boundary and initialconditions, as generally made (imposed) during the OECD ISPs. For this reason a new benchmark clearlydefining a list of still open issues has been recommended, with also a uniform protocol for calculations.

Reactor safety source-term activities. An assessment of UO2 vapourisation in different atmosphereswas performed against some experiments conducted at Berkeley University [B1.23] with the aim of testingthe fuel oxidation/vapourisation model implemented in ELSA [B1.24], which is the fission product releasemodule of the European reactor ASTEC [B1.25].

The experiments were modelled as a simple bare UO2 fuel mass inside a gas flow channel. As the modeldeparts from a fixed value of the equilibrium stoichiometrical deviation, the initial phase of experimentsleading to fuel oxidation was neglected and only the volatilisation phase due to steam ingress wasreproduced. Two steam-flow values of of 200 and 50 ccm were considered. The results show negligibledifferences in vapourisation rates. This is in goodagreement with the fact that the ELSA vapourisationmodel slightly depends on the inlet gas rate and onthe composition of the career gas. The calculatedpercentage of volatilised mass notably increases withtemperature, which is further confirmation of thecode capability to correctly calculate vapourisationrates.

Comparison of code results with the experimentaldata normalised to mass fraction release, as given bythe code, shows reasonably good agreementbetween calculation and data (fig. B1.43), thusproviding further confidence in the adequacy of thefuel volatilisation modelling in ASTEC.

Reliability and risk analysis

The following reliability and risk activities are performed within programmes promoted by internationalorganisations.

Ageing probability safety assessment. An official agreement has been signed between ENEA and theInstitute for Energy (IE) of the Joint Research Centre (JRC) of the European Commission, in Petten,

[B1.23] K. Hashizume et al., J. Nucl. Mater. 275, 277-286 (1999); and N. Davidovich, Validation of the ASTEC code fuel volatilization model onthe Hashizume et al. experiments - SARNET-ST-P20 (2006)

[B1.24] W. Plumecocq and G. Guillard, ELSA 2.1, ASTEC-V1/DOC/04-02 (2002); and N. Davidovich, Progress on synthesis modelling of UO2oxidation - SARNET-ST-P5, ENEA Internal Report FIS–P9G1–001 (2005)

[B1.25] W. Plumecocq and G. Guillard, ASTEC V1.2 code ELSA module, ASTEC-V1/DOC/05-06 (2006)

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5 5.5 6.56 7

1×10-7

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104/ T (1/K)

Exp.(mol/s/cm2)

ASTEC-DIVA(fractional volat. rate)

Exp. (normalised tofractional volat. rate)

Volatilisation rate of uranium in pure steamat flow rate 200 ccm

Fig. B1.43 – DIVA calculations compared with Hashizume

experimental data

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Netherlands, for participation in an international collaboration denoted as Network on IncorporatingAgeing Effects into Probabilistic Safety Assessment. The network is devoted to developing reliabilityand availability models of systems and components, incorporating the effects of aging, and isexpected to last till 2009.

During 2006 a study on the impact of ageing on passive systems and their performance wasundertaken, in addition to the definitions of basic ageing probabilistic safety assessment (APSA)reliability models.

Passive system reliability. The activities performed mainly addressed issues related to passivesystems relying on natural circulation to accomplish their functions:

• development of an approach for integrating the passive systems within an accident sequence incombination with active systems and human actions in a probabilistic risk assessment (PRA)framework, based on fault tree and event tree techniques;

• development of a preliminary reliability physics model based on the fracture mechanics approachto get the performance bounds to meet the reliability targets;

• evaluation of uncertainties associated with passive system reliability;

• risk study of a decay heat removal system based on failure mode, effects and critical analysis(FMECA);

• participation in the IAEA Co-ordinated Research Project (CRP), denoted as “Natural circulationphenomena, modelling and reliability of passive systems that utilise the natural circulation”,launched in 2004. In this framework an activity aimed at the reliability assessment of theArgentinean integral-type CAREM-like reactor passive features has been undertaken and resultsare expected at the beginning of the 2007.

B1.4 Nuclear Data

General quantum mechanics

Scattering by PT-symmetric non-local potentials. Non-local potentials play an important role inmany applications of quantum scattering theory. In nuclear physics, they naturally arise from theconvolution of an effective nucleon-nucleon interaction with the density of a target nucleus. Inparticular, a solvable non-local potential was proposed by Yamaguchi in 1954 in order to describebound and scattering states of the proton-neutron system. The present study was focussed on thescattering properties of a PT-symmetric 1D version of the Yamaguchi potential, i.e., a non-Hermitianpotential invariant under the product of the parity operator P and the time reversal operator T, butnot under the separate actions of P and T: the transmission and reflection coefficients are workedout by the Green’s function method and show aspects of unitarity breaking quite different from thoseof PT-symmetric local potentials. The method of solution can be applied to large families of non-localpotentials with separable kernel and different behaviour under P and T transformations.

Group theory approach to transparent potentials. One-dimensional potentials withtransmission coefficients equal to one over the whole real axis occur in several domains of generalquantum mechanics: for instance, non-trivial reflectionless potentials can be derived bysupersymmetric techniques from the null potential, which is trivially reflectionless, or they can beextracted by Lie-algebraic methods from the Casimir invariants of some non-compact groups. In thepresent study the latter technique was applied to derivation of the general form of real potentialsappearing in Hamiltonians with underlying so(2,2) symmetry, which permits the solution of thecorresponding Schrödinger equation in terms of hypergeometric functions. The six-generatorso(2,2) algebra admits several decomposition chains and the corresponding potentials are, ingeneral, not transparent: reflectionless potentials are obtained in the so(2,2) → so(2,1) → so(2)reduction chain when the solutions belong to discrete series representations of the so(2,1) sub-




algebra appearing in the reduction. Hyperbolic potentials of the Pöschl-Teller type belong to this class. TheInönü-Wigner contraction of so(2,2) to the pseudo-euclidean algebra e(2,1) yields solutions that are alwaysconnected with reflectionless potentials. For the sake of simplicity, but without loss of generality, thegeneral form has been worked out for reflectionless potentials appearing in Hamiltonians with underlyinge(1,1) symmetry, where e(1,1) is a three-generator sub-algebra of e(2,1). The well-known reflectionlesspotential V(x) ~ 1/x2 belongs to this class.

Nuclear reaction theory and experiments

Neutron-induced fission of light actinides. Withinthe work programme of theoretical activities of interestto the n_TOF collaboration, a model has beenproposed to describe the coarse-grained resonantstructure in neutron-induced fission of light actinides atsub-barrier excitation energies. The fission barriers areeither two-, or three-humped, depending on thefissioning nucleus, and have an imaginary componentin the second (isomeric) well, simulating a partialdamping of class II vibrational states, while class IIIstates, corresponding to excitations in the third well,are not damped. The sets of discrete transition statesinclude rotational bands built either on vibrational statesor on non-collective states. In the presentphenomenological version of the model, energies andquantum numbers of transition states are not evaluated by means of a nuclear structure model, but areadjusted on the experimental (n,f) cross sections, which can thus be reproduced with great accuracy, asshown in figure B1.44, relative to the first-chance fission of 232Th.

The present fission model has been incorporated in Version 19 (Lodi) of the EMPIRE-II code of nuclearreactions, freely distributed by the National Nuclear Data Center, Brookhaven National Laboratory.

Measurements of neutron-capture cross sections at the n_TOF facility at CERN. After the end ofthe experimental campaign in 2004, the two subsequent years were dedicated to analysis of capturecross-section measurements and to publication of related papers, such as those on 232Th(n,γ) in theunresolved resonance region up to 1 MeV, 151Sm(n,γ) in the energy range from 0.6 eV to 1 MeV, and209Bi(n,γ) in the resolved resonance region, already summarised in the ENEA UTS FIS 2005 ProgressReport. The new analysis completed and published in 2006 concerns the 207Pb(n,γ) reaction in theresolved resonance region. The measurement was performed with an optimised set up of two C6D6scintillator detectors, which permits reduction of scattered neutron background down to a negligible level,by using the pulse height weighting technique. Resonance parameters and radiative kernels weredetermined for 16 resonances in the neutron energy range from 3 to 320 keV. Good agreement withprevious measurements is found at low energies, while substantial discrepancies appear beyond 45 keV.Maxwellian averaged cross sections were determined with an accuracy of ± 5%.

Nuclear data processing and validation

The cooperation between the ENEA Nuclear Data Group and the Organisation for Economic Co-operationand Development/Nuclear Energy Agency (OECD/NEA) Data Bank (Issy-les-Moulineaux, France)continued, in particular, within the Joint Evaluated Fission and Fusion (JEFF) Working Group on BenchmarkTesting, Data Processing and Evaluations. Several technical feedbacks were notified, dedicated to theJEFF-3.1 European evaluated data files and their related processing through the NJOY nuclear dataprocessing system. A valuable collaboration with a specialist formerly working at the Institute of Physicsand Power Engineering (IPPE) Obninsk (Russian Federation) has been continued and extended.

Cro

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arns

)

Incident energy (MeV)

0.15

0.10

0.05

0

1.0 2.01.5 2.5

Current work2002 Shcherbakov1991 Fursov1986 Kanda1983 Meadows1982 Behrens1978 Blons1975 Blons

Fig. B1.44 – 232Th(n,f) near the fission threshold.

Solid line: present work. Experimental data are

taken from EXFOR

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VITJEFF31.BOLIB and MATJEFF31.BOLIB generation. The VITJEFF31.BOLIB andMATJEFF31.BOLIB coupled n-γ multi-group cross-section libraries for nuclear fission applications inthe VITAMIN-B6 American library energy group structure (199 neutron groups + 42 photon groups)were completely reprocessed by means of a version of the NJOY-99.112 nuclear data processingsystem, modified at ENEA. The present libraries, based on the JEFF-3.1 European evaluatednuclear data files, were previously produced through the NJOY-99.90 system, but it was decided toreprocess them completely after a detailed analysis of the list of modifications introduced by theauthor in the recent NJOY–99.112 version. The THERMR and GROUPR modules of this latterversion were further modified at ENEA. In particular, a correction patch was prepared andintroduced in the THERMR module of NJOY-99.112 in order to solve a problem that emerged in theprocessing of the JEFF-3.1 bound nuclides C (graphite) and Be (beryllium metal), where infinite loopcalculations were generated. A second relevant correction patch was prepared for the GROUPRmodule of NJOY–99.112. The OECD/NEA Data Bank checked this patch and got positive resultsand then diffused it freely. This initiative was taken in order to extend the group-wise data processingcapability to the evaluated data files including non-Cartesian interpolation schemes for secondaryneutron energy distributions (MF=5). The ENEA Nuclear Data Group proved that 69 JEFF-3.1evaluated files could not be processed correctly through the GROUPR module of NJOY-99.112 orthrough all previous NJOY versions officially released, as communicated to the NJOY User Group.This set of data files contains, in particular, secondary neutron energy distributions (MF=5),presented as arbitrary tabulated functions (LF=1) with the non-Cartesian unit base interpolation lawINT=22. The GROUPR module cannot process correctly the mentioned evaluated files because theGETSED subroutine cannot deal with secondary neutron energy distributions with non-Cartesianinterpolation schemes (INT=11-15 and INT=21-25). Thus, the group-to-group scattering matricesfor the MT=16, 17, 22, 28, 32, 33, 91 reactions could not be produced in the GENDF output crosssection files of the 69 evaluated data files under consideration. The GROUPR problems describedabove were autonomously identified, starting from analysis of unacceptably underestimated Keffresults obtained with criticality neutron transport calculations, performed through the XSDRNPM 1Ddiscrete ordinates module of the SCAMPI data processing system. Two ICSBEP (2004 Edition) fastcriticality benchmark experiments with 233U (included in the previously cited 69–file set) weresimulated. The results obtained with the XSDRNPM code in the P5-S16 approximation wereobtained from JEFF-3.1 data, processed differently with the original GROUPR module ofNJOY–99.112 and with the GROUPR version modified at ENEA into the 199 neutron energy groupstructure of the VITAMIN-B6 library. The results obtained with these deterministic transportcalculations were compared with the results obtained through the MCNP-4C Monte Carlo codeusing JEFF-3.1 continuous-energy cross-section sets.

181 materials were processed: 175 for standard isotopes or natural elements and 6 for boundnuclides. In the last group of materials, in particular, the H-Zr material was added to the set of 5bound nuclide materials contained in the VITAMIN-B6 library. Only one material (46Ca fromJEFF–3.1) could not be processed correctly. ENEA notified the OECD/NEA Data Bank of the factthat the total and elastic cross-section values of the first officially released version of this 46Ca filebelow 1 keV, i.e., in the energy range 1.0×10-05 - 1.0×1003 eV, are set to zero, while capture cross-section values differ from zero.

SCAMPI revision and updating. Many corrections and modifications were required for severalmodules of the SCAMPI data processing system in order to process the JEFF-3.1 data for theVITJEFF31.BOLIB library. In particular, the AJAX, MALOCS and SMILER modules were corrected.The most interesting modification was made to SMILER and MALOCS in order to take into accountalso the delayed component part (MF=5 and MT=455) of the fission spectrum, needed to obtain,e.g., more correct results in fixed-source transport calculations. On the contrary, the original versionof SMILER can read only the prompt component (MF=6 and MT=18).

The following versions of the MALOCS module were compared, as taken from the SCAMPI nucleardata processing and SCALE nuclear safety calculation systems:

• original version of MALOCS in the SCAMPI distributed by OECD/NEA Data Bank;




• version of MALOCS/SCAMPI as modified by ENEA, called MALOCS/SCAMPI Bologna version;

• original version of MALOCS included in SCALE-4;

• original most recent updated version of MALOCS included in SCALE-5.

From the performance and feature comparison of the versions of MALOCS included in the SCAMPI,SCALE-4 and SCALE-5 systems, the following conclusions were drawn:

• MALOCS/SCAMPI, MALOCS/SCALE-4 and MALOCS/SCALE-5 exclude the possibility of fission matrixcollapsing.

• MALOCS/SCALE-4 and MALOCS/SCALE-5 include the possibility to truncate the up-scatter cross-section terms with options IOPT7=0, 1, 2, 3.

• MALOCS/SCAMPI includes only IOPT7=0.

• MALOCS/SCALE-5 is similar to MALOCS/SCALE-4, but it is rewritten in FORTRAN-90.

MALOCS/SCAMPI Bologna version includes the possibility of fission matrix collapsing and permitstruncation of the up-scatter terms with options IOPT7=0, 1, 2, 3. Taking into account both theseconclusions and the fact that the SCAMPI system includes functional modules all programmed inFORTRAN-77, as for the MALOCS/SCAMPI Bologna version, it was preferred to avoid any potentialinconsistency in programming languages; therefore, this version was selected for the production of thenew BUGJEFF31.BOLIB collapsed working library from the multi-group general-purposeVITJEFF31.BOLIB library in AMPX format. The GENDF cross-section files, obtained through a modifiedversion of GROUPR in NJOY-99.112, were used to generate VITJEFF31.BOLIB and MATJEFF31.BOLIB.Extensive validation of the VITJEFF31.BOLIB library was performed through simulation of the same thermaland fast-neutron criticality benchmarks, already prepared for VITJEF22.BOLIB. The results obtained withthe XSDRNPM 1D transport module of SCAMPI were compared with the results of Monte Carlocalculations using the MCNP-4C code.

BUGJEFF31.BOLIB. Two preliminary versions (with and without up-scatter) of the cross-section workinglibrary BUGJEFF31.BOLIB were collapsed from the VITJEFF31.BOLIB library in AMPX format, generatedwith the ENEA modified version of NJOY-99.112. This collapsing work was done by means of the ENEArevised SCAMPI system and, in particular, the modified version of the MALOCS module. TheBUGJEFF31.BOLIB working library for shielding and light water reactor (LWR) pressure vessel dosimetryapplications has the same group structure (47 n + 20 γ) and general features as the BUGLE-96 Americanlibrary. To complete the response function cross section collapsing in the BUGLE-96 neutron groupstructure (47 n) from the most recent IAEA Reactor Dosimetry File IRDF-2002, a new tabulated weightingfunction was obtained from XSDRNPM calculations in the 1/4T (T=PWR pressure vessel thickness) spatialposition, using the VITJEFF31.BOLIB multi-group library. The calculation chain was completely preparedbut, before starting the collapsing procedure to generate the final working library, further investigation willbe necessary to identify the inconsistencies and inaccuracies of the BUGLE-96 input data, which emergedin 2005 in the ENEA feasibility analysis for a BUGLE-type library generation.

Computer code development

BOT3P is a set of standard FORTRAN-77 language codes developed by the ENEA Nuclear Data Group in1997. The BOT3P Version 1.0 was originally conceived as a set of standard FORTRAN-77 languageprogrammes in order to give the users of the DORT and TORT deterministic transport codes (both includedin the Oak Ridge National Laboratory [ORNL USA] DOORS package) some useful diagnostic tools toprepare and check their input data files for both Cartesian and cylindrical geometries, including mesh gridgeneration modules, graphical display and utility programs for post-processing applications. Later versionsextended the possibility to produce the geometrical, material distribution and fixed neutron source data toother deterministic transport codes such as TWODANT/THREEDANT (both included in the Los AlamosNational Laboratory [LANL] USA DANTSYS package), PARTISN (the updated parallel version of DANTSYS)and the sensitivity code SUSD3D (distributed by the OECD/NEA Data Bank, Issy-les-Moulineaux, France)and, potentially, to any transport code through BOT3P binary output files that can be easily interfaced (see,

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neutron, photon and charged particle transportcodes KASKAD-S-2.5 and KATRIN-2.0, developedat the Keldysh Institute of Applied MathematicsMoscow, Russian Federation). Since BOT3P binaryoutput files can be easily interfaced, users can

potentially produce the geometrical and materialdistribution data for any transport code starting from

the same BOT3P input. This makes it possible tocompare directly for the same geometry the effects on

transport analysis results, which stem from the use ofdifferent data libraries and solution approaches.

BOT3P Version 5.1 was completed in 2006 and has been freely available from the OECD/NEA DataBank (F) since August 2006. This new version contains important additions specifically addressingradiation transport analysis for medical applications. The new module CATSM allows users toreduce the geometrical size of problems related to processed (already interpreted by physicians orby proper software) computerised (axial) tomography (CT/CAT) scans with or without small detailloss with respect to the original voxelized geometry. This permits problem sizes that can be moreeasily managed by transport codes. CATSM can automatically generate tetrahedron mesh grids,too, starting from the input voxelized geometry, even though the implemented algorithm is still ratherrough and to be improved in the future. BOT3P-5.1 contains new graphics capabilities that enableusers to visualise tetrahedron mesh grids in 3D and 2D cuts. As from Version 5.0, a general methodto conserve mass of geometrically complex material zones simulated on both Cartesian andcylindrical mesh grids was implemented. BOT3P allows users to specify as refined a computationas desired of the possible area/volume error of material zones due to the stair-cased geometryrepresentation, and automatically corrects material densities in order to conserve masses globally.BOT3P can store on binary outputs the detailed material zone distribution map inside each cell ofthe mesh grid, according to a sub-mesh grid refinement defined in input by the user and thearea/volume fraction distribution of the different material zones contained in meshes at zoneinterfaces. This procedure allows a local (per cell) density correction as an alternative to theapproach of a uniform density correction on the whole zone domain and potentially makes itpossible to perform material zone homogenisation locally and transport analyses with moreaccuracy. BOT3P allows users to model X-Y, X-Z, Y-Z, R-Θ and R-Z geometries in two dimensionsand X-Y-Z and R-Θ-Z geometries in three dimensions. BOT3P was successfully used not only insome complex neutron shielding and criticality benchmarks, but also in power reactor applications(Westinghouse AP1000 internals heating rate distribution calculations by Ansaldo Nucleare). BOT3Pis designed to run on most Linux/UNIX platforms. The plot of figure B1.45 gives an idea of thecomplex modelling capabilities of BOT3P.

Radioactive ion-beam production for nuclear-structure studies

Intense neutron-rich isotope beams open many new fields of investigation, such as nuclear-structurestudies, in a yet unexplored region. Several laboratories are trying to produce high enough intensitiesto warrant a new generation of experiments. The Study for the Production of Exotic Species (SPES)project is an accelerator-based facility for the production of intense neutron-rich radioactive ionbeams, in the range of masses between 80 and 160. SPES is a new-generation ISOL facilityproposed in Italy at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN-LNL), able to represent a competitive intermediate step between the existing facilities and the longerrange high-performance EURISOL.



Fig. B1.45 – Simulation in Cartesian coordinates of a

complex geometry (120X, 88Y, 200Z)


The target system is one of the key issues forsuch facilities. A target configuration hasbeen developed, in an ENEA/INFN-LNLcollaboration, consisting of a 40-MeV protonbeam (0.2 mA) directly impinging on thefission materials, composed of uranium carbide (UCx). The 238U fission fragments constitute the source forthe exotic beams and, in order to extract them, the target is placed inside a graphite box at 2000°C. Thetarget is split into several thin disks to allow cooling of the system by thermal radiation (fig. B1.46). In thisway ∼1013 fissions s-1 are obtained with a relatively simple system and at relatively low cost. All the mainparameters of the system have been analysed by means of calculation codes: the fission rates and fissionfragment distribution; power deposition and the thermo-mechanical behaviour of the disks.

B1.5 TRIGA RC-1 and RSV TAPIRO Plant-Operation forApplication Development

The availability of the TRIGA RC-1 and RSV TAPIRO plants has permitted ENEA to acquire solid experiencein the development and management of research nuclear reactors and their application in programmesthat use ionizing radiation sources, in particular for the qualification of radiation damage to materials. Withthe qualified TRIGA RC-1 neutron beams it is possible to develop highly technological neutron radiographyand tomography techniques by means of thin scintillator films in lithium fluoride. The neutron tomographysystem located on the thermal column of the TRIGA reactor has been maintained in operation as apropaedeutic to the installation of a new collimator in the TRIGA tangential channel to improve the L/D ratioin a neutron flux of 108 n cm-2 s-1.

The TRIGA RC-1 and TAPIRO reactors have been proposed as experimental support to the new-generation nuclear reactors that are nearing commercialisation (e.g., AP 1000) in order to check criticalcomponents under thermal and fast neutron flux. In fact, the TRIGA core flexibility permits installation of anexperimental loop to continuously verify component performance under irradiation.

During 2006 the TRIGA and TAPIRO reactors operated for about 2000 h. The TAPIRO irradiation columnwas also modified to permit boron neutron capture therapy (BNCT) for human brain tumour and melanomaapplications (see sect. B2.1).

Window

Protonbeam

UCx disks Carbon dump

Fig. B1.46 – Target configuration for the SPES project

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B2.1 Boron Neutron Capture Therapy

In 2006 construction of the epithermal column EPIMED at the TAPIRO experimental nuclear reactorwas completed. The irradiation bunker to be used for beam characterisation was constructed andthe doses outside the bunker, both in and outside the reactor hall, were measured and comparedwith calculations. A network of national groups involved in measuring the beam has beenestablished to coordinate the beam characterisation. Support equipment for BNCT clinical trials hasbeen acquired from the Swedish BNCT project (Hammercap S.p.A.).

The collaborative activity with the Study and Production of Exotic Species (SPES)-BNCT project ofthe Legnano National Laboratory (LNL) of INFN and the University of Padua on using the thermalcolumn HYTHOR at TAPIRO in radiobiological and micro-dosimetric studies continued. HYTHORwas also used for film irradiation in a collaboration with the University of Bremen (Germany) and forthe development of gel dosimeters (University of Milan). A collaboration with INFN Pavia and co-financed by the Ministry of Higher Education and Research (MIUR) was launched to study theapplication of BNCT to lung tumours.

Design of a graphite configuration in the thermal column of the TRIGA reactor is under way. Theobjective is to repeat the clinical experimentation carried out on an explanted liver at Pavia. Extensivesupport in this activity has been provided by INFN Pavia.

The epithermal column EPIMED at TAPIRO

Human tissue has a relatively high tolerance to epithermal neutrons (in the BNCT context betweenabout 1 eV and 10 keV) which, unlike thermal neutrons, are able to penetrate some centimetres intothe tissue. However as the energy increases into the tens and hundreds of keV region the tolerance

strongly decreases. Figure B2.1compares the epithermal neutronspectrum at TAPIRO with theICRP74 flux-to-sievert conversioncoefficient. Although this coefficientis for stochastic doses, whilst intherapy much higher systematicdoses are involved, this comparisonillustrates the critical importance ofdesigning and measuring theneutron spectrum.

The different phases of assemblingthe moderator and reflector areshown in figure B2.2. The mounted

118

B2 Medical, Energetic and EnvironmentalApplications


"Epithermal" spectrum

Flux-to-Sievert rf (ICRP74)

Nor

mal

ised

neu

tron

flux

/uni

t le

thar

gy (

cm-2

s-1

)

1×100

1×10-2

1×10-41×100 1×1021×10-21×10-41×10-8 1×10-6

Energy (MeV)Fig. B2.1 – Comparison of epithermal neutron spectrum at TAPIRO

with a flux-to-sievert conversion factor


column outside and inside thereactor (in the latter casewithout the lithiatedpolyethylene end neutronshield) is shown in figure B2.3.

EPIMED provides a neutronbeam that directly enters thereactor hall. The necessarybeam shielding consists offirstly a bunker of limitedvolume appropriate for beamcharacterisation with thereactor operating at a maximum 10% of nominal power and secondly anirradiation room for patient therapy with the reactor at nominal power(5 kW). The bunker has been designed and constructed and the dosesaround the bunker in the reactor hall as well as outside the reactor hallhave been measured and compared with the predicted values.

Figure B2.4 shows a plan diagram of the bunker together with access maze and the shielding placedoutside the reactor hall. As the present shielding configuration is temporary, to save money and time, it hasbeen necessary to establish an exclusion zone outside the reactor hall in the direction of the neutron beam(fig. B2.4).

The bunker shielding is composed ofstandard (assumed density2.3 g cm–3) 50-cm-thick concreteblocks (so referring to figure B2.4 thereare two lines of concrete of totalthickness 1 m in the direction of thecontrol room). In addition the innerwalls of both the bunker and the firstpart of the access maze are lined with

Fig. B2.2 - Mounting the moderator and reflector

of EPIMED in TAPIRO

Sliding door Reactor hall

Entrance maze

bunker

Controlroom Air-lockCooling

systemroom

Fence

Externalconcreteshielding

Lawn

4341

42

Fig. B2.3 – The mounted column outside and

inside the reactor

Fig. B2.4 – Plan of bunker, access maze and

shielding outside the reactor hall and

exclusion zone (showing some of the points

used for dose comparison)

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borated polyethylene to reduce the production ofhigh-energy prompt gamma rays as well asactivation. The ceiling is borated polyethylene justover 10 cm thick covered by a thin layer of iron. Asa result, gamma rays from neutron capture in 10Bprovide quite high doses above the ceiling.However at ground level the doses resulting fromreflection of these gammas from the walls and roofof the reactor hall are relatively low. Figure B2.5shows various stages in the construction of thebunker, whilst figure B2.6 shows the completedbunker.

The measured and calculated doses outside thebunker are in reasonable agreement. As anexample, from [B2.1], figures B2.4 and B2.7 report

B2 Medical, Energetic and


Reactor hall

Control room

12

34

5

67

8(SR2)

9-1011

12

1314

15

(SR1)

Fig. B2.7 – Points for dose comparison, measurement/

calculation (see also fig. B2.4)

Fig. B2.6 – The completed characterisation bunker and access maze

Fig. B2.5 – Construction of the

characterisation bunker and access

maze


comparisons for selected dose points withinthe reactor hall and outside the hall at themargins of the limited access. Thecomparison between calculated andmeasured doses is shown in table B2.I.

Where the comparison is poor (e.g., point 7) the reason is known (in this case an unavoidable averagingof the calculated dose over a volume that includes the concrete shielding as well as air). Having establisheda degree of confidence on the calculated doses, it is possible consider the dose maps (e.g., in figure B2.8)of the total (neutron and gamma) doses in the reactor hall at about 1 m above the floor.

Employment of the thermal column HYTHOR at TAPIRO

The thermal neutron experimental facility HYTHOR, designed by the LNL-INFN Padua, has been used byLNL to carry out micro-dosimetric studies by means of specially designed tissue-equivalent proportionalcounters (TEPCs). HYTHOR has also been utilised by the University of Padua for mouse irradiation in thecontext of research into boron compounds for skin melanoma. Again in the BNCT framework, films forneutron capture radiography have been irradiated in collaboration with the University of Bremen.

In collaboration with the Department of Physics of Milan University, Monte Carlo calculations werecompared with experimental results by means of gel dosimeters in order to investigate a) the spatialdistribution of the gamma dose and thermal neutron fluence and b) the accuracy at which the boronconcentration should be estimated in an explanted organ of a BNCT patient.

Study of BNCT applied to lung tumours

A collaboration has started with the multi-disciplinary group at INFN Pavia, previously involved in thetreatment of the explanted liver, to study the application of BNCT to lung tumours. Calculations concerning

[B2.1] K.W. Burn, L. Casalini, E. Nava, Confronto tra calcoli e misure relativo al monitoraggio d’area del reattore TAPIRO per la caratterizzazionedella nuova colonna epitermica (EPIMED), ENEA Internal Report in preparation R

efer

ence

s

Environmental Applications

µSv/h

<2.000E-13.019E-14.557E-16.879E-11.038E+01.568E+02.366E+03.572E+05.392E+08.139E+01.229E+11.855E+12.800E+14.226E+16.379E+19.630E+11.454E+22.194E+23.312E+2

>5.000E+2

Fig. B2.8 – Calculated total dose map in the reactor hall

at about 1 m above the floor

Point Gamma Dose (µSv/h) Neutron Dose(µSv/h)Meas. Calc. Meas. Calc.

1 1.3 1.2 1.3 1.22 1.2 0.68 1.1 0.593 3.3 1.2 3.3 1.04 2.3 1.7 1.5 1.15 1.6 1.2 1.6 0.956 5.3 1.8 1.6 0.557 35.3 7.3 1.6 1.08 0.9 0.79 1.3 1.09 1.7 3.1 3 1.810 39 2.6 2.211 32 15 26 4412 21 6.9 5 2.013 55 17 9 2214 48 25 10 2815 2.6 1.4 1.4 1.841 1.2 0.44 0.3 0.1442 0.6 0.47 0.2 0.1143 0.9 0.34 0.1 0.10

Table B2.I – Comparison of selected measured andcalculated doses (see also figs. B2.7 and B2.4)

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employing the neutron beam from EPIMED.Measurements will be made on a lung modelphantom placed in the EPIMED beam.

Design of a facility at TRIGA to treatexplanted livers

This activity was initiated in 2006 with the support ofINFN Pavia. A different thermal column [B2.2] to theoriginal one used for liver irradiation [B2.3] wassuggested by Pavia. The modified configuration hasthe advantage of not requiring the liver to be rotatedby 180° during treatment. The MCNP model of TRIGAat ENEA Casaccia [B2.4] was improved in the vicinityof the thermal column and all the radial and tangentialexperimental ducts were included. The new thermalcolumn design [B2.2] was incorporated with a liverphantom [B2.3] and container (including a partialscreening layer of lithium fluoride to harden theneutron spectrum) supplied by Pavia. The resultingconfiguration is shown in figures B2.9 and B2.10.

The distribution of the therapeutic 10B dose in thephantom was calculated to verify that the graphiteconfiguration (fig. B2.9) together with the lithiumfluoride spectrum modifier gave a therapeutic dosecovering the whole phantom. An example of such adistribution is shown in figure B2.11 (from the PaviaTRIGA model, courtesy of the Department of Nuclearand Theoretical Physics, University of Pavia and INFN,Pavia). Figure B2.12 shows an axial profile of thetherapeutic dose along the central axis.



Fig. B2.9 – Plan view a) and vertical cross section b) of the

TRIGA reactor core and thermal column with phantom

12

8

4

010

105

5-5-5-10 -10

00

Boron dose distribution 2nd z mesh

Dos

e (a

rb.u

nits

)

Axial mesh No Radial mesh NoFig. B2.11 – Typical qualitative distribution of

therapeutic dose within liver phantom (courtesy

of Department of Nuclear and Theoretical

Physics, University of Pavia and INFN, Pavia)

Fig. B2.10 – Plan view of the TRIGA reactor


Whilst results for the distribution of the dose within the phantomagree quite closely with those obtained at the Pavia TRIGA, theabsolute values of the doses differ considerably. The differencesarise because lead is used as a gamma shield at Casaccia, whilebismuth is used at Pavia, and masonite is present in the thermalcolumn at Casaccia (some modelling differences are also evident).A first conclusion is that the therapeutic doses at Casaccia will notbe very much larger than those at Pavia, notwithstanding the factthat the nominal reactor power is four times higher at Casaccia thanat Pavia.

B2.2 Solar Thermal Energy

Experimental activities under the Solar ThermalEnergy Project are aimed at evaluating thebehaviour of several kinds of structural materialin stagnant molten nitrate environments. Inparticular, the corrosion mechanism/rate andweld resistance have been evaluated.

The experimental facility (fig. B2.13) is made upof eight crucibles (fig. B2.14), coated inside withTi, in which the specimens are inserted (orextracted) by means of a special device(fig. B2.15). Each crucible is equipped with itsown heater and electronic control system formonitoring and acquiring pressure andtemperature.

Tests were carried out on austenitic steel (AISI321H). In selecting the specimen geometry thetype of test was taken into account: simplerectangular slabs for the corrosion mechanismtests and corrosion rate evaluation; rectangularwelding slabs for evaluation of the tungsten inertgas (TIG) weld resistance in molten salt. Thetests were performed in a nitrate mixture ofsodium and potassium (40 wt.% NaNO3 –60 wt.% KNO3).

[B2.2] S. Bortolussi, Neutron flux distribution in liver at the Pavia reactor, presented at the Workshop on Innovative Treatment Concepts forLiver Metastases (University Hospital Essen 2006)

[B2.3] S. Bortolussi, TAOrMINA: una originale configurazione del campo neutronico per una migliore uniformità della dose nell’organoespiantato, degree thesis, Department of Physics, University of Trieste (2002-2003)

[B2.4] N. Burgio et al., MCNP model of the 1 MW TRIGA MARK II at ENEA Casaccia, ENEA Internal Report FIS-P815-017 (2005) Ref

eren

ces


Dos

e (a

rb. u

nits

)

28

26

24

22

20

18

16

14

410 420 430415 425 435Axial mesh No

Fig. B2.12 – Typical profile of the 10B dose in the phantom along the axis

of the thermal column

Fig. B2.13 – View of the experimental facility, special device

for introducing/extracting specimens and the monitoring

acquisition system

Fig. B2.14 – External and internal view of the crucibles

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compare the pre- and post-testanalyses: visual inspection, surfacearea and roughness measurement,weight, x-ray analysis (only for thewelded specimens). In the post-testanalysis the optical microscopy

(scanning electron microscopy and energy dispersive x-ray spectroscopy) analysis was taken intoaccount. The static tests ended after 8000 h at 590°C.

B2.3 Development Activities for Antarctic Drilling

Talos Dome is an ice dome (72°48’S; 159°06’E, 2316 m) on the edge of the East Antarctic plateauand adjacent to the Victoria Land Mountains in the western Ross Sea area. The firn coretemperature is -41°C, and average snow accumulation over the last eight centuries is 80 kg/m2/yr.Airborne radar measurements indicate that the dome summit is situated above sloping bedrock (icethickness 1880 ± 25 m ), but there is relatively flat bedrock 5-6 km distant along the SE ice divide(ID1 159°11’00”E, 72°49’40”S, 2315 m), about 770 ± 25 m in elevation and covered by1545 ± 25 m of ice (fig. B2.16).



Ice thickness (m):ID1=1545 ± 25mTD summit=1880 ± 25m

Bedrock elevation (WGS84 m):ID1= 770 ± 25mTD summit=440±25m

TD Summit

TDSummit

ID1

ID1

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Southern Ocean

Southern Ocean290 km

LawDome

Dome CEPICA

Vostok

TaylorDome

TalosDome

RossSea

Ross Sea SipleDome500

550 km

1100 km

1500 km

0km

ReevesGlacier Terra Nova

Bay Station

Wilkes S

ubglacial Basin

LegendCore siteWind directionMain ice divide10m contour lineRock outcrop

Weddel SeaKohnen

Dome Fuji

Vostok

Dome CRoss Sea

Byrd

Berken IslandBerken Island

Talos DomeTalos Dome0 1000 2000km

Fig. B2.16 – Talos Dome

geographic position

Fig. B2.15 – Special device for

introducing/extracting specimens


Drilling at Talos Dome should greatly increaseknowledge about the response of near-coastal sites to climate changes and theHolocene history of accumulation rates in theRoss Sea region. In addition, this ice recordwill strongly contribute to understanding thelast glacial-interglacial transition whendifferent climatic features and trends areobserved between West-East Antarctica(Byrd, Vostok, EPICA-Dome C, Dome Fuji,Law Dome) and two near-coastal sites in theRoss Sea sector (Taylor and Siple Dome).Lastly it would give an idea of the futurevariability of accumulation and dynamicchanges in this sensitive area.

The Talos Dome Ice (TALDICE) project iscurrently drilling to bedrock at the ID1 site,and one glacial/interglacial period of usablerecord is expected. The project is also aimedat developing integrated instrumentation inorder to improve the Italian capability to drilland measure the ice core and to plan andmanage both the mechanical parts and theelectronic control system of the newperforation system.

The project started in the field in November2004. In this first season one French and fourItalian technicians and a scientist wereinvolved for about 50 days in drilling activitiesand in setting up a temporary field camp(summer camp), using the vehicles, modulesand tents of the International Trans AntarcticScientific Expedition (ITASE) programme(fig. B2.17).

During the second season, from November2005 to January 2006, for about 80 dayseleven technicians and scientists (3 Frenchand 8 Italian) were involved in TALDICEactivity. The camp was opened on 7November. The first 40 days of the seasonwere dedicated to re-building the roof of theperforation trench and setting up both the drill facilities inside the trench and the camp infrastructures.

During the first drilling season from 17 December 2005 to 15 January 2006 the final depth of -607.74 mwas reached, equal to ~7500 years ago. The ice cores to 480 m depth were analysed by a dielectricprofiling instrument, then cut, put in plastic bags, packed in boxes and sent to Europe for further analyses.

The camp for the second campaign of perforation (fig. B2.18) was opened on 7 November 2006 during


Sleeping and storages

Science trench anddrill generator

Runway andTO fuel

Snow for water

Camp fuel

Main generator and living

Cargo line

Trenchentrance

Fig. B2.17 – Talos Dome remote camp

-600

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29/11/06 START OF THE SEASON: -600.84M

3 Dec. 1° week: 32.49 m, -633.29 m

10 Dec. 2° week: 52.04 m, -685.44 m

17 Dec. 3° week: 146.10 m, -831.64 m

24 Dec. 4° week: 149.17 m, -980.71 m

31 Dec. 5° week: 117.83 m, -1098.54 m

7 Jan. 6° Week: 122.30m, -1220.84m

11 Jan. end drill season: -1293.86 mLogged Depth: -1300.58 m

25 Dec. Christmas day off

26 Dec. M1 motor problempower generator problem

01 Jan. new year day off

Problem with PLC-Inverter Stop 6-7 Dec.

Dep

th (

m)

Fig. B2.18 – Perforation progress graph season 2006-2007

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Fig. B2.20 – Tephra Layers

Start perforation 29 November 2006

End perforation 11 January 2007

Duration of perforation 36 useful days

Logged depth 1300.58 m

Drilling depth 1293.86 m

Drilling length this season 693 m

Packed, cut and sent depth 486 m (from 478.00 to 666.00 m from 1001.00 to 1300.00 m)

Liquid level end of season(density=0.958 g cm-3) 109 m

Daily average 19.25 m

Average liquid/m 17.41 m

Run number 386

Core length average/run 1.79 m

Total recovered chips ice 4950 kg (7 kg chips/m)

Perforation hours 501 h

Core length average/ perforation hours 1.37 m/h

Table B2.II – Perforation season 2006-2007 final data

Fig. B2.19 – 27 December 2006: 1000 m of perforation


the ongoing Antarctic Campaign (2006-2007). The drilling season was started on 29 November and willterminate 11 January 2007, with the final depth of –1300.58 m, corresponding to approxi mately 60,000to 80,000 years ago. The original objective, 1200 m, has been surpassed, meaning that all the ice coveringthe last deglaciation and the end of the last glaciation is up at the surface. The material will be studied inthe laboratories of the European countries (Italy, France, German, Switzerland and UK) involved in theproject (fig. B2.19).

The visible tephra layers observed during this season total 35, of which 10 are particularly dense(fig. B2.20). These layers will be very useful for getting one exact dating of the ice extracted duringperforation. Table B2.II reports the final data of the 2006-2007 perforation season. The Antarctic bed rock,situated at a depth of approximately-1550 m should be reached during the next perforation campaign2007-2008.


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In relation to ENEA’s institutional role as the national focal point and advisor for nuclear-energy-related scientific and technological issues, the department ensures that ENEA (and Italy as a whole)is represented in the principal committees and bodies concerned with the pacific use of nuclearenergy, at national (Ministry of Economic Development [MSE]) and international (Nuclear EnergyAgency [NEA], International Atomic Energy Agency [IAEA], Euratom, etc.) levels. Representativesand experts from the department are present in nearly all the NEA standing committees (NSC, NDC,CSNI, RWMC, CRPPH) as well as in the steering committees, and in a number of IAEA permanent

Scientific & Technological Country Agency/Institution

Commissariat à l’Energie Atomique (CEA) FRANCE

Forschungszeuntrum Karlsruhe (FZK) GERMANY

Oak Ridge National Laboratory (ORNL) USA

Belgian Nuclear Research Centre (SCK-CEN) BELGIUM

Joint Research Centre - Institute for Transuranium EUROPEAN COMMISSIONElements (JRC-ITU)

Paul Scherrer Institute (PSI) SWITZERLAND

Seoul National University (SNU) SOUTH KOREA

Institut Laue-Langevin (ILL) FRANCE

Institute of Mathematics and Mechanics, RUSSIAUral branch of the Russian Academic of Science(IMM-RAS)

Table B3.I - Bilateral agreements

B3 Participation in International Working Groupsand Associations


technical working groups (TWGs), for example, on fast reactors, advanced technologies for light waterreactors, on fuel performance and technology, etc. Finally, a senior researcher of the department acts asnational delegate in the Consultative Committee Euratom-Fission (CCE-Fission).

The department also administers several bilateral agreements with major international organisations (seetable B3.I) in the nuclear fission field to ensure that R&D activities of common interest are performedsynergically.

Field of Co-operation Thematic area

Nuclear fission Physics, safety, technologies andcode developments for nuclearreactors

Accelerator–driven systems & Fuel cycle strategies, transmutationtransmutation systems and HLM Technologies

Advanced fission reactors Experimental testing, computersimulations, design and performance of advanced reactors

Accelerator–driven systems Physics and technologies for ADS

Accelerator–driven systems ADS technologies and advancedand partitioning and transmutation fuels

Spallation neutron sources Physics and HLM technologies

Nuclear fission HLM technologies

Irradiation in high flux reactors Nuclear Instrumentation, diagnosticsand materials

Nuclear and conventional Exp. measurements, computeraccident analysis simulations and code developments

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B4.1 Publications

Articles

R&D on Nuclear FissionC. HELLWIG, M. STREIT, P. BLAIR, F.C. KLAASSEN, R.P.C. SCHRAM, F. VETTRAINO, T. YAMASHITA: Inertmatrix fuel behaviour in test irradiationsJ. Nucl. Mater. 352, 291-299 (2006)

M. STREIT, T. TVERBERG, W. WIESENACK, F. VETTRAINO: Inert matrix and thoria fuel irradiation at aninternational research reactorJ. Nucl. Mater. 352, 263-267 (2006)

F. BIANCHI, C. ARTIOLI, K.W. BURN, G. GHEPARDI, S. MONTI, L. MANSANI, L. CINOTTI, D. STRUWE, M.SCHIKORR, W. MASACHEK, H.A. ABDERRAHIM, D. DE BRUYN, G. RIMPAULT: Status and trend of coredesign activities for heavy metal cooled accelerator driven system

Energy Convers. Manage. 47, 2698-2709 (2006)

S. ANDRIAMONJE, S. AUNE, G. BAN, S. BREAUD, C. BLANDIN, E. FERRER, B. GESLOT, A. GIGANON,I. GIOMATARIS, C. JAMMES, Y. KADI, P. LABORIE, J.F. LECOLLEY, J. PANCIN, M. RAILLOR, R. ROSA, L.SARCHIAPONE, J.C. STECKMEYER, J. TILLER: New neutron detector based on micromegas technologyfor ADS projectNucl. Intrum. Method A562, 755-759 (2006)

G. BENAMATI, A. GESSI, P.-Z. ZHANG: Corrosion experiments in flowing LBE at 450°CJ. Nucl. Mater. 356, 1-3, 198-202 (2006)

C. FOLETTI, G. SCADDOZZO, M. TARANTINO, A. GESSI, G. BERTACCI, P. AGOSTINI, G. BENAMATI:ENEA experience in LBE technologyJ. Nucl. Mater. 356, 1-3, 264-272 (2006)

P. AGOSTINI, L. SANSONE, G. BENAMATI, C. PETROVICH, S. MONTI: Neutronic and thermo-mechaniccalculations for the design of the TRADE spallation targetNucl. Instrum. Method Phys. Res. 562, 849-854 (2006)

A. MATHIS, S. MONTI: Energia nucleare: l’opzione del futuro; prima e seconda parteTermotecnica, Marzo N. 36-Aprile N.58 (2006)

L. BURGAZZI, R. FERRI, B. GIANNONE: Safety assessment of a liquid targetNucl. Eng. Des. 236, 4, 359-367 (2006)

130

B4 Publications



L. BURGAZZI: Probabilistic safety analysis of an accelerator-lithium target based experimental facility

Nucl. Eng. Des. 236, 12, 1264-1274 (2006)

F. CANNATA, A. VENTURA: Scattering by PT-symmetric non-local potentialsCzech. J. Phys. 56, 943-951 (2006)

G. A. KERIMOV, A. VENTURA: Group-theoretical approach to reflectionless potentialsJ. Math. Phys. 47, 082108, 1-16 (2006)

M. SIN, R. CAPOTE, A. VENTURA, M. HERMAN, P. OBLOŽINSKY: Fission of light actinides: 232Th(n,f) and231Pa(n,f) reactionsPhys. Rev. C 74, 014608, 1-13 (2006)

G. AERTS, U. ABBONDANNO, H. ALVAREZ, F. ALVAREZ-VELARDE, S. ANDRIAMONJE, J. ANDRZEJEWSKI, P.ASSIMAKOPULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN, F. BEČVÁR, E. BERTHOUMIEUX, F. CALVIÑO, D.CANO-OTT, R. CAPOTE, A. CARRILLO DE ALBORNOZ, P. CENNINI, V. CHEPEL, E. CHIAVERI, N. COLONNA, G.CORTES, A. COUTURE, J. COX, M. DAHLFORS, S. DAVID, I. DILLMAN, R. DOLFINI, C. DOMINGO-PARDO, W.DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L. FERRANT, A. FERRARI, R. FERREIRA-MARQUES,L. FITZPATRICK, H. FRAIS-KOELBL, K. FUJII, W. FURMAN, I. GONCALVES, E. GONZALEZ-ROMERO, A.GOVERDOSKI, F. GRAMEGNA, E. GRIESMAYER, C. GUERRERO, F. GUNSING, B. HAAS, R. HAIGHT, M. HEIL,A. HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA, Y. KADI, F. KÄPPELER, D. KARADIMOS, D.KARAMANIS, M. KERVENO, V. KETLEROV, P. KOEHLER, V. KONOVALOV, E. KOSSIONIDES, M. KRTIČKA, C.LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S. LUKIC, J. MARGANIEC, L. MARQUES, S.MARRONE, P. MASTINU, A. MENGONI, P.M. MILAZZO, C. MOREAU, M. MOSCONI, F. NEVES, H.OBERHUMMER, S. O’BRIEN, M. OSHIMA, J. PANCIN, C. PAPACHRISTODOULOU, C. PAPADOPOULOS, C.PARADELA, N. PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, M. T. PIGNI, R. PLAG, A. PLOMPEN, A.PLUKIS, A. POCH, C. PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G.RUDOLF, P. RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G. TAGLIENTE, J.L. TAIN,L. TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN, M. C. VINCENTE,V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M. WIESCHER AND K. WISSHAK (The

n_TOF Collaboration): Neutron capture cross section of 232Th measured at the n_TOF facility at CERN in theunresolved resonance region up to 1 MeVPhys. Rev. C 73, 054610, 1-10 (2006)

S. MARRONE, U. ABBONDANNO, G. AERTS, F. ALVAREZ-VELARDE, H. ALVAREZ-POL, S. ANDRIAMONJE, J.ANDRZEJEWSKI, G. BADUREK, P. BAUMANN, F. BEČVÁR, J. BENLLIURE, E. BERTHOMIEUX, F. CALVIÑO, D.CANO-OTT, R. CAPOTE, P. CENNINI, V. CHEPEL, E. CHIAVERI, N. COLONNA, G. CORTES, D. CORTINA, A.COUTURE, J. COX, S. DABABNEH, M. DAHLFORS, S. DAVID, R. DOLFINI, C. DOMINGO-PARDO, I. DURAN-ESCRIBANO, M. EMBID-SEGURA, L. FERRANT, A. FERRARI, R. FERREIRA-MARQUES, H. FRAIS-KOELBL, K.FUJII, W. I. FURMAN, R. GALLINO, I. F. GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F.GRAMEGNA, E. GRIESMAYER, F. GUNSING, B. HAAS, R. HAIGHT, M. HEIL, A. HERRERA-MARTINEZ, S. ISAEV,E. JERICHA, F. KÄPPELER, Y. KADI, D. KARADIMOS, M. KERVENO, V. KETLEROV, P. E. KOEHLER, V.KONOVALOV, M. KRTIČKA, C. LAMBOUDIS, H. LEEB, A. LINDOTE, M. I. LOPES, M. LOZANO, S. LUKIC, J.MARGANIEC, J. MARTINEZ-VAL, P. F. MASTINU, A. MENGONI, P. M. MILAZZO, A. MOLINA-COBALLES, C.MOREAU, M. MOSCONI, F. NEVES, H. OBERHUMMER, S. O’BRIEN, J. PANCIN, T. PAPAEVANGELOU, C.PARADELA, A. PAVLIK, P. PAVLOPOULOS, J. M. PERLADO, L. PERROT, M. PIGNATARI, M. T. PIGNI, R. PLAG,A. PLOMPEN, A. PLUKIS, A. POCH, A. POLICARPO, C. PRETEL, J. M. QUESADA, S. RAMAN, W. RAPP, T.RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G. RUDOLF, P. RULLHUSEN, J. SALGADO, J. C. SOARES,C. STEPHAN, G. TAGLIENTE, J. L. TAIN, L. TASSAN-GOT, L. M. N. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A.VENTURA, D. VILLAMARIN-FERNANDEZ, M. VINCENTE-VINCENTE, V. VLACHOUDIS, F. VOSS, H. WENDLER,

M. WIESCHER AND K. WISSHAK (The n_TOF Collaboration): Measurement of the 151Sm(n,γ) cross section from0.6 eV to 1 MeV via the neutron time-of-flight technique at the CERN n_TOF facilityPhys. Rev. C 73, 034604, 1-18 (2006)

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C. DOMINGO-PARDO, U. ABBONDANNO, G. AERTS, H. ÁLVAREZ-POL, F. ALVAREZ-VELARDE, S.ANDRIAMONJE, J. ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN,F. BEČVÁR, E. BERTHOUMIEUX, F. CALVIÑO, D. CANO-OTT, R. CAPOTE, A. CARRILLO DE ALBORNOZ,P. CENNINI, V. CHEPEL, E. CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M. DAHLFORS,S. DAVID, I. DILLMAN, R. DOLFINI, W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L.FERRANT, A. FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, K. FUJII, W.FURMAN, R. GALLINO, I. GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F. GRAMEGNA, E.GRIESMAYER, C. GUERRERO, F. GUNSING, B. HAAS, R. HAIGHT, M. HEIL, A. HERRERA-MARTINEZ, M.IGASHIRA, S. ISAEV, E. JERICHA, Y. KADI, F. KÄPPELER, D. KARAMANIS, D. KARADIMOS, M. KERVENO,V. KETLEROV, P. KOEHLER, V. KONOVALOV, E. KOSSIONIDES, M. KRTIČKA, C. LAMBOUDIS, H. LEEB,A. LINDOTE, I. LOPES, M. LOZANO, S. LUKIC, J. MARGANIEC, L. MARQUES, S. MARRONE, P.MASTINU, A. MENGONI, P. M. MILAZZO, C. MOREAU, M. MOSCONI, F. NEVES, H. OBERHUMMER, M.OSHIMA, S. O’BRIEN, J. PANCIN, C. PAPACHRISTODOULOU, C. PAPADOPOULOS, C. PARADELA, N.PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, R. PLAG, A. PLOMPEN, A. PLUKIS, A. POCH, C.PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G. RUDOLF, P.RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G. TAGLIENTE, J. L. TAIN, L.TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN, M. C.VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M. WIESCHER, AND K.

WISSHAK (The n_TOF Collaboration): New measurement of neutron capture resonances in 209Bi

Phys. Rev. C 74, 025807, 1-10 (2006)

C. DOMINGO-PARDO, U. ABBONDANNO, G. AERTS, H. ÁLVAREZ-POL, F. ALVAREZ-VELARDE, S.ANDRIAMONJE, J. ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN,F. BEČVÁR, E. BERTHOUMIEUX, S. BISTERZO, F. CALVIÑO, D. CANO-OTT, R. CAPOTE, C. CARRAPIC¸O,P. CENNINI, V. CHEPEL, E. CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M.DAHLFORS, S. DAVID, I. DILLMAN, R. DOLFINI, W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L. FERRANT, A. FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, K.FUJII, W. FURMAN, R. GALLINO, I. GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F.GRAMEGNA, E. GRIESMAYER, C. GUERRERO, F. GUNSING, B. HAAS, R. HAIGHT, M. HEIL, A.HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA, Y. KADI, F. KAPPELER, D. KARAMANIS, D.KARADIMOS, M. KERVENO, V. KETLEROV, P. KOEHLER, V. KONOVALOV, E. KOSSIONIDES, M. KRTICKA,C. LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S. LUKIC, J. MARGANIEC, S. MARRONE,P. MASTINU, A. MENGONI, P. M. MILAZZO, C. MOREAU, M. MOSCONI, F. NEVES, H. OBERHUMMER,M. OSHIMA, S. O’BRIEN, J. PANCIN, C. PAPACHRISTODOULOU, C. PAPADOPOULOS, C. PARADELA, N.PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, R. PLAG, A. PLOMPEN, A. PLUKIS, A. POCH, C.PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G. RUDOLF, P.RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G. TAGLIENTE, J.L. TAIN, L.TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN, M. C.VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M. WIESCHER, AND K.

WISSHAK (The n_TOF Collaboration): Resonance capture cross section of 207PbPhys. Rev. C 74, 055802, 1-6 (2006)

R. ORSI: A general method of conserving mass in complex geometry simulations on mesh grids and itsimplementation in BOT3P5.0Nucl. Sci. Eng. 154, 247-259 (2006)

J.J. KLINGENSMITH, Y.Y. AZMY, J.C. GEHIN, R. ORSI: Tort solutions to the three-dimensional MOXBenchmark, 3-D extension C5G7MOX

Prog. Nucl. Energy 48, 445 455 (2006)

E. BOTTA, R. ORSI: Westinghouse AP1000 internals heating rate distribution calculation using a 3-Ddeterministic transport methodNucl. Eng. Des. 236, 1558-1564 (2006)

B4 Publications



A. ANDRIGHETTO, C.M. ANTONUCCI, S. CEVOLANI, C.PETROVICH, M. SANTANA LEITNER: Multifoil UCx targetfor the SPES project - an updateEurop. Phys. J. A 30, 591-601 (2006)

L. BURGAZZI: Failure mode and effect analysis application for the safety and reliability analysis of a thermal-hydraulic passive systemNucl. Technol. 156, 2, 150-158 (2006)

Medical, Energetic and Environmental Applications

K.W. BURN, C. DAFFARA, G. GUALDRINI, M. PIERANTONI, P. FERRARI: Treating voxel geometries in

radiation protection dosimetry with a patched version of the Monte Carlo Codes MCNP and MCNPXRadiat. Prot. Dosim. doi:10.1093/rpd/ncl150, OUP (2006)

Reports

R&D on Nuclear Fission

G. GLINATSIS: Safety aspects of the EFIT/MgO - Pb core, ENEA Internal Report FPN-P815-005 (2006)

M. SAROTTO, C. ARTIOLI: Possible solutions for the neutronic design of the two zones EFIT-MgO/Pb core, ENEA

Internal Report FPN-P815-001(2006)

M. SAROTTO, C. ARTIOLI, V. PELUSO: Preliminary neutronic analysis of the three zones EFIT-MgO/Pb core, ENEA

Internal Report FPN-P815-004 (2006)

M. SAROTTO, C. ARTIOLI, V. PELUSO: MgO/Pb core neutronic preliminary analysis, ENEA Internal Report FIS-P815-021, EFIT (2006)

P. MELONI: A Neutronics-thermal-hydraulics model for preliminary studies on TRADE dynamics, ENEA InternalReport FIS-P99R-006 (2006)

G. BANDINI: Interpretation of TRIGA experimental data with SIMMER-III code for RELAP5 model evaluation and

transient analysis, ENEA Internal Report FIS-P99R-007 (2006)

G. BANDINI, P. MELONI: Analysis of BETHSY experiment 4.3b with ASTEC V1.2 code for CESAR thermal-

hydraulic module validation, ENEA Internal Report FPN-P9D0-001 (2006)

G. BANDINI: ICARE/CATHARE calculation of the QUENCH-11 experiment in the frame of the IRSN participation

in the SARNET benchmark, ENEA Internal Report FPN-P9D0-002 (2006)

G. BANDINI: Analysis of the OECD LOFT fission product experiment LP-FP-2 with ASTEC V1.2.1 code, ENEA

Internal Report FPN-P9G1-001 (2006)

G. BANDINI: Validation of CESAR thermal-hydraulic module of ASTEC V1.2 code on BETHSY experiments, ENEAInternal Report FIS-P9D0-002 (2006)

R. CAPONETTI: Determination by thermochemical calculation of speciation and deposition of fission product and

structural material during the vercors HT 1 experiment, ENEA Internal Report FIS-P127-042 (2006)

R. ORSI: BOT3P Version 5.1: two/three-dimensional mesh generator and graphical display of geometry and results

for deterministic transport codes, ENEA Report RT/2006/34/FIS (2006)

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R. ORSI: BOT3P Version 5.1: a pre-post-processor system for transport analysis, ENEA Internal ReportFIS-P9H6-014 Rev.0 (2006)

R. ORSI: CATSM: a pre-processor tool for medical applications, ENEA Internal Report FIS-P9H6-015 Rev.0(2006)

S. CEVOLANI: Valutazione approssimata dell’effetto della frequenza di pulsazione del fascio sulla termica

del target sottile per SPES, ENEA Internal Report FIS-P815-022 (2006)

A. ANDRIGHETTO, C. ANTONUCCI, S. CEVOLANI, C. PETROVICH: ENEA contribution to the design of the

thin target for the SPES project, ENEA Internal Report FIS-P815-020 (2006)

S. CEVOLANI: Termica della camera del target lamellare per SPES, ENEA Internal Report FPN-P815-(2006)

Medical, Energetic and Environmental Applications

M. BASTA, E. NAVA, G. ROSI: Monitoraggio d’area del reattore TAPIRO. Proposta di modifica, ENEAInternal Report FPN-TLE TAPIRO 06/02 (2006)

Contributions to Conferences

R&D on Nuclear FissionR. CALABRESE, F. VETTRAINO, T. TVERBERG: Inert matrix fuel modelling: transuranus analysis of theHalden IFA-652 first irradiation cycleInter. Workshop on Materials Models and Simulation for Nuclear Fuels (MMSNF-5), Nice (France), June 1-

2, 2006

R. CALABRESE, F. VETTRAINO, T. TVERBERG: Low burn-up inert matrix fuels performance: transuranusanalysis of the Halden IFA-652 first irradiation cycle

14th Inter. Conference on Nuclear Engineering (ICONE-14), Miami (USA), July 17-20, 2006

S. BOURG, C. CARAVACA, E. WALLE, G. DE ANGELIS, R. MALMBECK, G.B. LEWIN, J. UHLIR, T. INOUE,V. LUCA: Pyrochemistry within EUROPART from the acquisition of basic data to the processes for thetreatment of spent fuels

9th IEM on Actinide and Fission Product Partitioning and Transmutation, OECD Nuclear Energy Agency (9-IEMPT), Nimes (France), September 25-29, 2006

C. MADIC, M. J. HUDSON, P. BARON, N. OUVRIER, C. HILL, F. ARNAUD, A. G. ESPARTERO, J.F.DESREUX, G. MODOLO, R. MALMBECK, S. BOURG, G. DE ANGELIS AND J. UHLIR: EUROPART.European research programme for partitioning of minor actinides within high active wastes issuing from thereprocessing of spent nuclear fuels. Some of the principal results obtained

9th IEM on Actinide and Fission Product Partitioning and Transmutation, OECD Nuclear Energy Agency (9-

IEMPT), Nimes (France) September 25-29, 2006

F. BIANCHI, R. FERRI: Accident analysis of the windowless target systemTopical Meeting on Advances In Nuclear Analysis and Simulation (PHYSOR-2006), Vancouver (Canada),September 10-14, 2006

F. BIANCHI, R. FERRI, V. MOREAU: Transient thermo-hydraulic analysis of the windowless target systemfor the lead bismuth eutectic cooled accelerator driven system


B4 Publications



P. AGOSTINI, M. CIOTTI, C. PETROVICH, M. CARTA, N. ELMI, L. SANSONE, D. BELLER, C. KRAKOWIAK, A.BERGERON: Target study for the RACE HP experiment


P. AGOSTINI, M. CIOTTI, C. KRAKOWIAK, C. PETROVICH, G. BENAMATI, A. BERGERON, N. ELMI, G. GRANGET,L. SANSONE, M. SCHIKORR: Target study for the RACE HP experiment

8th Inter. Workshop on Spallation Materials Technology (IWSMT-8), Taos (USA), October 16-20, 2006

M. CARTA, N. BURGIO, A. D’ANGELO, A. SANTAGATA, C. PETROVICH, M. SCHIKORR, D. BELLER, L. SANFELICE, G. IMEL, M. SALVATORES: Electron versus proton accelerator driven sub-critical system performanceusing TRIGA reactors at powerTopical Meeting on Advances In Nuclear Analysis and Simulation (PHYSOR-2006), Vancouver (Canada),

September 10-14, 2006

W. AMBROSINI, G. BENAMATI, S. CARNEVALI, C. FOLETTI, N. FORGIONE, F. ORIOLO, G. SCADDOZZO, M.TARANTINO: Experiments on gas injection enhanced circulation in a pool-type liquid metal apparatus

XXIV Congresso Nazionale UIT, Napoli (Italy), June 21-23, 2006

A. RENIERI: L’integrazione delle competenze nello sviluppo di sistemi nucleari innovativi Convegno L’uso pacifico dell’energia nucleare da Ginevra 1955 ad oggi: Il caso italiano, Rome (Italy), March 8–9, 2006

A. RENIERI, S. MONTI: Le attività di R&S dell’ENEA nel contesto europeo ed internazionale del nuovo nucleare dafissione: sinergie e collaborazioni in Italia e all’esteroConvegno Nazionale AEIT, Capri (Italy), September 16-20, 2006

S. MONTI: IRIS integral test: experimental investigation of small break LOCAs in coupled vessel/containmentintegral reactors

15th IRIS Team Meeting, Pittsburgh (USA), April 25-27, 2006

S. MONTI: IRIS activities in the framework of the Italian national program on nuclear fission

16th IRIS Team Meeting, Santander (Spain), November 7-9, 2006

L. CINOTTI, C. FAZIO, J. KNEBEL, S. MONTI, H. AIT ABDERRAHIM, C. SMITH, K. SUH: LFR lead-cooled fastreactorConference on EU Research and Training in Reactor Systems (FISA 2006), Kirchberg, Luxembourg, March 13-16,2006

S. MONTI: Status and perspectives of Italian activities in the field of fast spectrum nuclear systemsIAEA Technical Meeting on Review of National Programmes on Fast Reactors and Accelerator Driven Systems,

39th TWG-FR Annual Meeting (CIAE), Beijing (China), May 15-19, 2006

S. MONTI: Planned R&D and technology activities in Italy for the development of the GENIV lead-cooled fastreactorIAEA Technical Meeting, Vienna (Austria), December 6-8, 2006

P. MELONI: Overview of helium cooled system applications with RELAP at ENEA2006 Inter. Congress on Advances in Nuclear Power Plant (ICAPP ’06), Reno (USA), June 4-8, 2006

G. BANDINI, P. MELONI, N. TRÉGOURÈS, J. FLEUROT: Post-test analysis of the BETHSY experiment 9.1b withASTEC V1.2 Code for CESAR thermal-hydraulic module validation NENE International Conference, Portoroz (Slovenia), September 18-21, 2006

G. BANDINI, G. GUILLARD, J. FLEUROT: Participation in the SARNET benchmark: analysis of the QUENCH-11experiment with ICARE/CATHARE code

12th Inter. QUENCH Workshop, Forschungszentrum Karlsruhe (Germany), October 24-26, 2006

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S. EDERLI: ENEA activity in the WP9.3,

SARNET CORIUM Topic 2nd Annual Review Meeting, Villigen (Switzerland), January 30-31, 2006

G. REPETTO, S. EDERLI: Assessment of the heat transfer and late phase model of the ICARE/CATHAREcode against debris bed in pile experiments

18th National & 7th ISHMT-ASME Heat and Mass Transfer Conference, Guwahati (India), January 4-6, 2006

L. BURGAZZI, M. MARQUES: Integration of passive system reliability in PSA studies


L. BURGAZZI: Probabilistic design of a passive system2006 ANS Winter Meeting, Albuquerque (New Mexico), November 12-16, 2006

L. BURGAZZI: Development of probability distributions of passive system failure

3rd Inter. Symposium on Systems & Human Science: Complex Systems Approaches for Safety, Securityand Reliability (SSR 2006), Vienna (Austria), March 6-8, 2006

L. BURGAZZI: Reliability aspects of passive systemsEC Enlargement and Integration Workshop on Use of Probabilistic Safety Assessment (PSA) for Evaluationof Impact of Ageing Effects on the Safety of Nuclear Power Plants, Bucharest (Romania), October 2-4,

2006.Invited talk

L. BURGAZZI: Incorporation of ageing effects into component reliability and availability modelsEurop. Safety and Reliability Conference (ESREL ’06), Estoril (Portugal), September 18-22, 2006

M. HEIL, U. ABBONDANNO, G. AERTS, H. ÁLVAREZ-POL, F. ALVAREZ-VELARDE, S. ANDRIAMONJE, J.ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN, F. BEČVÁŘ, E.BERTHOUMIEUX, S. BISTERZO, F. CALVIÑO, D. CANO-OTT, R. CAPOTE, C. CARRAPICO, P. CENNINI, V.CHEPEL,E. CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M. DAHLFORS, S. DAVID, I.DILLMAN, R. DOLFINI, CÉSAR DOMINGO PARDO, W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L. FERRANT, A. FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, K.FUJII, W. FURMAN, R. GALLINO, I. GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F.GRAMEGNA, E. GRIESMAYER, C. GUERRERO, F. GUNSING, B. HAAS, R. HAIGHT, A. HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA, Y. KADI, F. KÄPPELER, D. KARAMANIS, D.KARADIMOS, M. KERVENO, V. KETLEROV, P. KOEHLER, V. KONOVALOV, E. KOSSIONIDES, M. KRTI CKA,C. LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S. LUKIC, J. MARGANIEC, S. MARRONE,P. MASTINU, A. MENGONI, P.M. MILAZZO, C. MOREAU, M. MOSCONI, F. NEVES, H. OBERHUMMER, M.OSHIMA, S. O’BRIEN, J. PANCIN, C. PAPACHRISTODOULOU, C. PAPADOPOULOS, C. PARADELA, N.PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, R. PLAG, A. PLOMPEN, A. PLUKIS, A. POCH, C.PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G. RUDOLF, P.RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G. TAGLIENTE, J.L. TAIN, L.TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN, M. C.VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M. WIESCHER, K.WISSHAK (The n_TOF Collaboration): Neutron capture cross section measurements for nuclearastrophysics at n_TOF

9th Inter. Symposium on Nuclei in the Cosmos (NIC-IX), CERN (Geneva), June 25-30, 2006, SISSAProceedings of Science (http://pos.sissa.it/), PoS (NIC-IX) 053

M. MOSCONI, M. HEIL, F. KÄPPELER, R. PLAG, A. MENGONI, K. FUJII, R. GALLINO, G. AERTS,R.TERLIZZI, U. ABBONDANNO, H. ÁLVAREZ-POL, F. ALVAREZ-VELARDE, S. ANDRIAMONJE, J.ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN, F. BEČVÁŘ, E.BERTHOUMIEUX, S. BISTERZO, F. CALVIÑO, D. CANO-OTT, C. CARRAPIÇO, R. CAPOTE, P. CENNINI, V.CHEPEL, E. CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M. DAHLFORS, S. DAVID, I.DILLMAN, R. DOL NI, C. DOMINGO PARDO W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-

B4 Publications



SEGURA, L. FERRANT, A. FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, W.FURMAN, I. GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F. GRAMEGNA, E. GRIESMAYER, C.GUERRERO, F. GUNSING, B. HAAS, R. HAIGHT, A. HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA,Y. KADI, D. KARAMANIS, D. KARADIMOS, M. KERVENO, V. KETLEROV, P. KOEHLER, V. KONOVALOV, E.KOSSIONIDES, M. KRTI CKA, C. LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S. LUKIC, J.MARGANIEC, S. MARRONE, P. MASTINU, P.M. MILAZZO, C. MOREAU, F. NEVES, H. OBERHUMMER, M.OSHIMA, S. O'BRIEN, J. PANCIN, C. PAPACHRISTODOULOU, C. PAPADOPOULOS, C. PARADELA, N.PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, A. PLOMPEN, A. PLUKIS, A. POCH, C. PRETEL, J.QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G. RUDOLF, P. RULLHUSEN, J. SALGADO,L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G. TAGLIENTE, J.L. TAIN, L. TASSAN-GOT, L. TAVORA, G.VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN, M. C. VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S.WALTER, H. WENDLER, M. WIESCHER, K. WISSHAK (The n_TOF Collaboration): Experimental challenges for theRe/Os Clock

9th Inter. Symposium on Nuclei in the Cosmos (NIC-IX), CERN (Geneva), June 25-30, 2006, SISSA Proceedingsof Science (http://pos.sissa.it/), PoS (NIC-IX) 055

C. DOMINGO PARDO, U. ABBONDANNO, G. AERTS, H. ÁLVAREZ-POL, F. ALVAREZ-VELARDE6, S.ANDRIAMONJE, J. ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN, F.BEČVÁŘ, E. BERTHOUMIEUX, S. BISTERZO, F. CALVIÑO, D. CANO-OTT, R. CAPOTE, C. CARRAPIÇO, P.CENNINI, V. CHEPEL, E. CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M. DAHLFORS, S. DAVID,I. DILLMAN, R. DOLFINI, W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L. FERRANT, A.FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, K. FUJII, W. FURMAN, R. GALLINO, I.GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F. GRAMEGNA, E. GRIESMAYER, C. GUERRERO, F.GUNSING, B. HAAS, R. HAIGHT, M. HEIL, A. HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA, Y.KADI, F. KÄPPELER, D. KARAMANIS, D. KARADIMOS, M. KERVENO, V. KETLEROV, P. KOEHLER0, V.KONOVALOV, E. KOSSIONIDES, M. KRTICKA, C. LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S.LUKIC, J. MARGANIEC, S. MARRONE, P. MASTINU, A. MENGONI, P.M. MILAZZO, C. MOREAU, M. MOSCONI,F. NEVES, H. OBERHUMMER, M. OSHIMA, S. O’BRIEN, J. PANCIN, C. PAPACHRISTODOULOU, C.PAPADOPOULOS, C. PARADELA, N. PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, R. PLAG, A.PLOMPEN, A. PLUKIS, A. POCH, C. PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C.RUBBIA, G. RUDOLF, P. RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G.TAGLIENTE, J.L. TAIN, L. TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D.VILLAMARIN, M. C. VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M.WIESCHER, K. WISSHAK (The n_TOF Collaboration): Neutron capture measurements on the s-processtermination isotopes, lead and bismuth

9th Inter. Symposium on Nuclei in the Cosmos (NIC-IX), CERN (Geneva), June 25-30, 2006, SISSA Proceedingsof Science (http://pos.sissa.it/), PoS (NIC-IX) 058

S. MARRONE, U. ABBONDANNO, G. AERTS, H. ÁLVAREZ, F. ALVAREZ-VELARDE, S. ANDRIAMONJE, J.ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN, F. BEČVÁŘ , E.BERTHOUMIEUX, F. CALVIÑO, D. CANO-OTT, R. CAPOTE, C. CARRAPIÇO, P. CENNINI, V. CHEPEL, E.CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M. DAHLFORS, S. DAVID, I. DILLMANN,R.DOLFINI, C. DOMINGO-PARDO, W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L. FERRANT,A. FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, K. FUJII, W. FURMAN, R. GALLINO,I. GONCALVES, E. GONZALEZ-ROMERO, A. GOVERDOVSKI, F. GRAMEGNA, E. GRIESMAYER, C. GUERRERO,F. GUNSING, B. HAAS, R. HAIGHT, M. HEIL, A. HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA, Y.KADI, F. KÄPPELER, D. KARAMANIS, D. KARADIMOS, M. KERVENO, V. KETLEROV, P. KOEHLER, V.KONOVALOV, E. KOSSIONIDES, M. KRTIČKA, C. LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S.LUKIC, J. MARGANIEC, P. MASTINU, A. MENGONI, P.M. MILAZZO, C. MOREAU, M. MOSCONI, F. NEVES, H.OBERHUMMER, S. O'BRIEN, M. OSHIMA, J. PANCIN, C. PAPACHRISTODOULOU, C. PAPADOPOULOS , C.PARADELA, N. PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, M. PIGNATARI, R. PLAG, A. PLOMPEN, A.PLUKIS, A. POCH, C. PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C. RUBBIA, G.

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RUDOLF, P. RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, G. TAGLIENTE,J.L. TAIN, L. TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN,M.C. VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M. WIESCHER,

K.WISSHAK (The n_TOF Collaboration): Astrophysical implications of the 139La(n,γ) and 151Sm(n,γ) crosssections measured at n_TOF


G. TAGLIENTE, U. ABBONDANNO, G. AERTS, H. ÁLVAREZ, F. ALVAREZ-VELARDE, S. ANDRIAMONJE, J.ANDRZEJEWSKI, P. ASSIMAKOPOULOS, L. AUDOUIN, G. BADUREK, P. BAUMANN, F. BEČVÁŘ, E.BERTHOUMIEUX, F. CALVIÑO, D. CANO-OTT, R. CAPOTE, A. CARRILLO DE ALBORNOZ, P. CENNINI, V.CHEPEL, E. CHIAVERI, N. COLONNA, G. CORTES, A. COUTURE, J. COX, M. DAHLFORS, S. DAVID, I.DILLMANN, R. DOLFINI, C. DOMINGO-PARDO, W. DRIDI, I. DURAN, C. ELEFTHERIADIS, M. EMBID-SEGURA, L. FERRANT, A. FERRARI, R. FERREIRA-MARQUES, L. FITZPATRICK, H. FRAIS-KOELBL, K.FUJII, W. FURMAN, C. GUERRERO, I. GONCALVES, R. GALLINO, E. GONZALEZ-ROMERO, A.GOVERDOVSKI, F. GRAMEGNA, E. GRIESMAYER, F. GUNSING, B. HAAS, R. HAIGHT, M. HEIL, A.HERRERA-MARTINEZ, M. IGASHIRA, S. ISAEV, E. JERICHA, Y. KADI, F. KÄPPELER, D. KARAMANIS, D.KARADIMOS, M. KERVENO, V. KETLEROV, P. KOEHLER, V. KONOVALOV, E. KOSSIONIDES, M. KRTIČKA,C. LAMBOUDIS, H. LEEB, A. LINDOTE, I. LOPES, M. LOZANO, S. LUKIC, J. MARGANIEC, L. MARQUES,S. MARRONE, C. MASSIMI, P. MASTINU, A.MENGONI, P.M. MILAZZO, C. MOREAU, M. MOSCONI, F.NEVES, H. OBERHUMMER, S. O'BRIEN, M. OSHIMA, J. PANCIN, C. PAPACHRISTODOULOU, C.PAPADOPOULOS, C. PARADELA, N. PATRONIS, A. PAVLIK, P. PAVLOPOULOS, L. PERROT, R. PLAG, A.PLOMPEN, A. PLUKIS,A. POCH, C. PRETEL, J. QUESADA, T. RAUSCHER, R. REIFARTH, M. ROSETTI, C.RUBBIA, G. RUDOLF, P. RULLHUSEN, J. SALGADO, L. SARCHIAPONE, I. SAVVIDIS, C. STEPHAN, J.L.TAIN, L. TASSAN-GOT, L. TAVORA, R. TERLIZZI, G. VANNINI, P. VAZ, A. VENTURA, D. VILLAMARIN, M.C.VINCENTE, V. VLACHOUDIS, R. VLASTOU, F. VOSS, S. WALTER, H. WENDLER, M. WIESCHER,

K.WISSHAK (The n_TOF Collaboration): Measurement of the 90,91,92,94,96Zr neutron capture cross sectionsat n_TOF


C. GUERRERO R. CAPOTE, A. MENGONI et al. (The n_TOF Collaboration): Measurement at n_TOF of the237Np(n, γ) and 240Pu(n,γ) cross sections for the transmutation of nuclear wasteANS Topical Meeting on Reactor Physics (PHYSOR-2006), Vancouver (Canada), September 10-14, 2006

W. DRIDI ET AL. (The n_TOF Collaboration): Measurement of the neutron capture cross section of 234U inn_TOF at CERNANS Topical Meeting on Reactor Physics (PHYSOR-2006), Vancouver (Canada), September 10-14, 2006

F. GUNSING et al. (The n_TOF Collaboration): Measurement of the neutron capture cross section of 236UANS Topical Meeting on Reactor Physics (PHYSOR-2006), Vancouver (Canada), September 10-14, 2006

A. ANDRIGHETTO, C. ANTONUCCI, M. BARBUI, S. CARTURAN, F. CERVELLERA, S. CEVOLANI, M.CINAUSERO, P. COLOMBO, A. DAINELLI, P. DI BERNARDO, F. GRAMEGNA, G. MAGGIONI, G.MENEGHETTI, C. PETROVICH, L. PIGA, G. PRETE, V. RIZZI, M. TONEZZER, D. ZAFIROPOULOS, P.ZANONATO: The SPES direct UCx target

7th Inter. Conference on Radioactive Nuclear Beams (RNB-7), Cortina d’Ampezzo (Italy), July 3-7, 2006

A. ANDRIGHETTO, C. ANTONUCCI, M. BARBUI, S. CARTURAN, F. CERVELLERA, S. CEVOLANI, M.CINAUSERO, P. COLOMBO, A. DAINELLI, P. DI BERNARDO, F. GRAMEGNA, G. MAGGIONI, G.MENEGHETTI, C. PETROVICH, L. PIGA, G. PRETE, V. RIZZI, M. TONEZZER, D. ZAFIROPOULOS, P.ZANONATO: The SPES direct UCx targetIX Inter. Conference on Nucleus-Nucleus Collisions, Rio de Janeiro (Brazil), August 28-September 1, 2006

B4 Publications



F. GRAMEGNA, A. ANDRIGHETTO, C. ANTONUCCI, M. BARBUI, L. BIASETTO, G. BISOFFI, S. CARTURAN, L.CELONA, F. CERVELLERA, S. CEVOLANI, F. CHINES, M. CINAUSERO, P. COLOMBO, M. COMUNIAN, G.CUTTONE, A. DAINELLI, P. DI BERNARDO, E. FAGOTTI, M. GIACCHINI, M. LOLLO, G. MAGGIONI, M.MANZOLATO, G. MENEGHETTI, G.E. MESSINA, A. PALMIERI, C. PETROVICH, A. PISENT, L. PIGA, G. PRETE,M. TONEZZER, M. RE, V. RIZZI, D. RIZZO, D. ZAFIROPOULOS, P. ZANONATO: The SPES direct target project atLNLZakopane Conference on Nuclear Physics, Zakopane (Poland), September 4-10, 2006

Medical, Energetic and Environmental ApplicationsK. W. BURN, L. CASALINI, S. MARTINI, D. MONDINI, E. NAVA, G. ROSI, R. TINTI: Final design and constructionissues of the TAPIRO epithermal column

12th Inter. Congress on Neutron Capture Therapy (ISNCT-12), Takamatsu (Japan), October 9-13, 2006, ISNCTProceedings, p. 564 (2006)

G. GAMBARINI, S. AGOSTEO, S. ALTIERI, S. BORTOLUSSI, M. CARRARA, S. GAY, M. MARIANI, C. PETROVICH,G. ROSI, E. VANOSSI: Dose imaging with gel dosimeters in phantoms exposed in reactor thermal columnsdesigned for BNCT

12th Inter. Congress on Neutron Capture Therapy (ISNCT-12), Takamatsu (Japan), October 9-13, 2006, ISNCTProceedings, p. 417 (2006)

P. FERRARI, G. GUALDRINI, E. NAVA, K. W. BURN: Preliminary evaluations of the undesirable patient dose froma BNCT treatment at the ENEA-TAPIRO reactor

10th Symposium on Neutron Dosimetry, Uppsala (Sweden), June 12-16, 2006

G. GAMBARINI, S. AGOSTEO, S. ALTIERI, S. BORTOLUSSI, M. CARRARA, S. GAY, E. NAVA, C. PETROVICH, G.ROSI, M. VALENTE: Dose distributions in phantoms irradiated in thermal columns of two different nuclear reactors


J. ESPOSITO, G. ROSI, S. AGOSTEO: The new hybrid thermal neutron facility at TAPIRO reactor for BNCTradiobiological experiments


K.W. BURN, L. CASALINI, E. NAVA, G. ROSI, R. TINTI: The epithermal column for BNCT at the TAPIRO reactorWorkshop on Innovative Treatment Concepts for Liver Metastases, University Hospital Essen (Germany),December 7-9, 2006

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C1.2 Entrustment of ENEA’s Fuel Cycle Facilities andPersonnel to Sogin

The management of ENEA’s fuel cycle facilities (EUREX Saluggia - spent fuel reprocessing; ITRECTrisaia - spent fuel reprocessing; IPU Casaccia - fuel element fabrication; OPEC Casaccia - post-irradiation analysis) has been assigned to the Società Gestione Impianti Nucleari SpA (Sogin)through the “Entrustment of Management Act” and integrating annexes, signed by the ENEADirector General and the Sogin Executive Manager on 23 December 2005. ENEA has seconded itsexpert personnel to Sogin to enable full operability of the facilities and to ensure that all the technicalprescriptions be achieved and that the activities concerning site decommissioning be fully exploited.

C1.3 Characterisation, Treatment and Conditioning ofNuclear Materials and Radioactive Waste

The Laboratory for the Characterisation of Nuclear Materials at ENEA Casaccia, in collaboration withthe universities, carries out nuclear and radioactive material analyses, R&D on reprocessing fuelused in new-generation reactors (e.g., PYREL project, see sect. B1.1) and is the reference lab forcharacterisation of conditioned/non-conditioned radioactive waste. Above all the laboratory has toguarantee Italy the functions of radioactive-material characterisation and process qualification. Thelaboratory manages four operative areas: two classified areas (C-43 Radiochemical Laboratory andC-25 Technological Hall - Zone A) and two cold areas (CETRA Laboratory and C-25 TechnologicalHall - Zone B).

The C-43 Radiochemical Laboratory is authorised through a Category A decree to carry out non-destructive measurements of radioactive waste and materials by means of gamma spectrometrysystems. Table C1.I briefly describes the available techniques.

The first two techniques, implemented on the SEA radioactive-waste gamma analyser

C1 Radioactive Waste Management andAdvanced Nuclear Fuel Cycle Technologies


In 2006 ENEA’s Department of Nuclear Fusion and Fission, and Related Technologies (Dipartimento Fusione,

Tecnologie e Presidio Nucleare [FPN]) acted according to national policy and to the role assigned to ENEA

FPN by Law 257/2003 with regard to radioactive waste management and advanced nuclear fuel cycle

technologies.

140


(SRWGA, fig. C1.1), have the same field of application but are characterised by different levels ofaccuracy according to activity and density distribution of the matrix, while for the electrical capacitancetomography/transmission computer tomography (ECT/TCT) techniques these characteristics have noinfluence on the reliability of results. The weakness of ECT/TCT is only the measuring time (typically18 h/drum). It is also worth noting that when the segmented gamma scanner (SGS) is used, variations inmatrix density and in the activity distribution inside the matrix could lead to overestimation orunderestimation of the real activity up to a factor of 10.

The ISOCS (fig. C1.2) is used in a wide variety of measurement applications. The most importantcharacteristic of the ISOCS is its capability to obtain radionuclide activity by applying pre-defined geometrytemplates in the analysis software: defining thetemplate, the user obtains an evaluation of theoverall efficiency curve without needingexperimental calibration. However, themeasurement configuration has to be defined andreproduced by the user with good accuracy, eventhough this is not always allowed because ofpractical problems.

In 2006 experimental measurement campaignswere carried out to validate the ISOCS and assess

Measurement technique Field of application Input Output

Emission & transmission Characterisation of 220–and - Volume of the drum Total Activity and relativeaxial scan segmented 400–litre drums containing - Collimation axial distribution for eachgamma scanner (SGS) gamma emitter radionuclides - Radionuclide library radionuclide identified

- Quantitative analysis reportsSoftware: Segment 2.1 given by the spectroscopy

software Genie 2k

Angular scanning (AS) Characterisation of 220–and - Detection efficiency curve Number, position and400–litre drums containing for point source activity of each identified

Software: Ascanio 1.1 gamma emitter radionuclides - Linear attenuation factor radionuclide- Radionuclide library - Quantitative analysis reports

given by the spectroscopysoftware Genie 2k

Low–resolution Characterisation of 220 and - Detection efficiency curve - Spatial attenuation emisssion & transmission 400 litre drums containing for point source factor distributiontomography ((ECT/TCT) gamma emitter radionuclides - Linear attenuation factor - Spatial activity distribu-

- Radionuclide library tion for each Software Plinius 1.1 - Quantitative analysis reports radionuclide identified

given by the spectroscopy - Total activity for each software Genie 2k radionuclide identified

In-situ object counting Characterisation of various - Accurate description of - Total activity for eachsystem (ISOCS) objects containing gamma measurement configura- radionuclide identified

emitter radionuclides tionSoftware: Genie2k - Radionuclide library

ISOXSW

Table C1.I - Techniques used for nondestructive measurements of radioactive wastes & materials

Fig. C1.1 - SRWGA gamma system

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its performance. Measurements were performed on several220-litre drums (with differing matrix density and distribution)equipped with various configurations of certified gamma-emitting sources placed at different positions. The aim was toillustrate the problems that can compromise the applicationof this measurement technique and to simulate the followingreal situations:

• characterisation of 220-litre raw waste drums andconditioned waste drums;

• localisation and quantification of buried and coveredactivity;

• quantification of activity in sealed containers.

The results obtained have clearly defined the field of application of ISOCS (for small samples or, withappropriate measurements and analysis procedures, for large samples and buried activity) and willbe the basis for future research activities and for setting up the technical procedure to be accreditedaccording to ISO-17025 in autumn 2007. The same activity was foreseen for 400-litre drums, but itwas put forward to 2007 because of mechanical problems with the SRWGA.

The CETRA Laboratory is specialised in the formulation and characterisation of matrices forconditioning toxic and/or radioactive wastes. In accordance with the Technical Guide 26 of theItalian Agency for Environmental Protection and Technical Services (APAT) for the management ofradioactive waste, the laboratory studies, qualifies and sets up processes for treating andconditioning radioactive wastes and performs the chemical and physical-mechanicalcharacterisation of the conditioned products, obtained via the employment of chemical elementssimulating real waste.

The qualification of the conditioningprocesses consists of a series of activitiesaimed at demonstrating that the matrixresulting from the conditioning processcomplies with the minimum requirements forinterim storage, transport and clearance ofwaste. The major tests performed are tensilestrength (fig. C1.3); cyclic temperaturegradient resistance; radiation damageresistance; fire resistance; leaching test; freeliquid absence; bio-degradation resistanceand immersion resistance. Some tests (bio-degradation resistance, leaching test andradiation damage resistance) are performedin cooperation with other ENEA laboratories.

C1.4 Radioprotection and Human Health

Methodological proposal for the evaluation of a physiological comfort index inindoor environments

Carried out in the framework of a research activity supported by the National Institute ofOccupational Safety, Health and Prevention (ISPESL), the aim is to propose a physiological comfort

C1 Radioactive Waste Management


Fig. C1.2 - ISOCS detector

Fig. C1.3 - Tensile strength tester


index for workers wearing personal protective equipment. Many attempts have been made to combineenvironmental with physiological parameters in order to develop a single index. Currently there are manyindices, but none of them is widely accepted. The main reason lies in the great complexity and plurality ofinteractions among the main factors to take into account when defining the index. A survey onphysiological comfort indices showed that the Physiological Strain Index (PSI) is the most appreciated asindividual reactions to it are only based on core temperature and heart rate. Moreover, the PSI can assessin real time physiological responses both to heat and heat strain between any combination of climate,clothing and work rate. The PSI does not consider sweat rate because of the intrinsic difficulty inperforming an on-line measurement: nevertheless this term should be taken into account, especially in thecase of short and repeated operations.

The work, carried out with La Sapienza University of Rome, proposes the use of two physiological comfortindices: the first concerns long-lasting operations; the second, short and repeated operations. In the firstcase the suggested index is like the PSI index; it is possible to take into account the effects of coolingdevices operating with personal protective equipment by reducing the index value. In the second caseanother term linked to sweat rate can be introduced. To calculate the value of coefficients in the newphysiological comfort index, it is necessary to carry out a measurement campaign on a sufficiently widepopulation. These measurements should lead to a quantitative evaluation of the importance of the termconsidering the presence of cooling systems in personal protective equipment.

LCA of strippable coating and the principal competing technology used for nucleardecontamination

Life cycle assessment (LCA) is a systematic way to evaluate the environmental impact of products oractivities throughout their entire life cycle by following a “cradle to grave” approach. This approach impliesthe identification and quantification of emissions, materials and energy consumption, which affect theenvironment at all stages of the entire life cycle of the product. The application of strippable coatings is aninnovative technology for decontamination of nuclear plants and for any decontamination project where thepurpose is to remove surface contamination (such as polychlorobiphenyls (PCBs), asbestos particles, etc).It effectively reduces hazardous residuals, at low cost. An adhesive plastic coating is applied on thecontaminated surface. The strippable coating is allowed to cure for up to 24 h, after which it can be easilypeeled. The coating traps the contaminants in the polymer matrix. Strippable coatings are non-toxic anddo not contain volatile compounds or heavy metals. Since the coating constitutes solid waste, disposal iseasier than treating contaminated liquid wastes produced by the baseline technology.

The competing baseline technology is the steam vacuum cleaning technology based on superheatedpressurised water, used to remove contaminants from floors and walls. The LCA was carried out tocompare the strippable coating with the steam vacuum technology. The functional unit of the study isrepresented by a surface of 1 m2 to be decontaminated. The results of LCA achieved using SimaPro 5.0 ® software confirmed the good environmental performance of strippable coatings. The storagephase is the phase showing the most important differences between the two technologies. For this reasonthis phase was studied in detail, even from the economic point of view. A simplified economic analysis ofonly the storage phase showed higher costs for the steam vacuum technology. In a further developmentof the work, the cost of all the phases could be examined in order to confirm or not the best behaviour ofthe strippable coating, also from the economic point of view.

C1.5 Integrated Service for Non-Energy Radwaste

Radioactive waste is generated in a broad range of activities involving the use of radioactive material indifferent conventional fields, such as medicine, industry, agriculture, research and education. In general thewaste generated in these fields is often limited in volume and activity; however it has to be managed likethe other radwaste from nuclear power plants.

and Advanced Nuclear Fuel Cycle Technologies

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Italy has no radwaste national repository, so Government has entrusted ENEA with the managementof radioactive waste coming from small producers (collection, transport, characterisation, treatment,conditioning, interim storage, or release for waste with short life radio-nuclides, after theirradioactivity decay). ENEA has organised a special technical-operative service, called “IntegratedService”, and is responsible for the guidance, supervision and control of the whole cycle of wastemanagement. ENEA has entrusted NUCLECO SpA with the operative and commercial tasks, andoffered the company access to specific facilities and infrastructures, located at the CasacciaResearch Centre. The two parties drew up a special agreement laying out mutual duties andresponsibilities.

Integrated Service has also collected thirty disused sealed radioactive sources with Cs-137 andCo–60 and about seventy grams of Ra-226 no longer used in medical therapy. Except for this lasttype of waste, ENEA becomes the owner of all the radwaste collected and deals with the finalrelease, leaving the waste producers free of any juridical responsibility. Integrated Service is availableto private companies operating in this sector. The companies supply collecting services andtemporary storage. ENEA provides qualification for the companies and gives them specifictechnical-operational procedures.

C1.6 Transport of Nuclear Material

Packaging for transport of radioactive material

The Laboratory for Characterisation of Nuclear Materials is a permanent member of the EuropeanNetwork of Testing Facilities for the Quality Checking of Radioactive Waste Packages. (EN-TRAP:created in 1992 on the initiative of the European Commission.) The objectives are to promotecollaboration on the development, application and standardisation of quality checking for wastepackages. The network involves the reference laboratories of the European Union member statesthat verify the regulatory issues on waste packages. In this framework the laboratory participates insteering committee meetings and in technical-scientific activities regarding the characterisation ofthe radioactive wastes, promoted by the working groups. In 2006 one meeting of the steeringcommittee took place in April at Winfrith (UK) and one meeting of working group D (QualityChecking of ILW/HLW), in September in Brussels.

As ENEA-NUCLECO (see sect. C1.5) has to store, transport and dispose of radio needles and somelarge radioactive sources, the following activities have been carried out:

• Preparation of a management system for quality assurance. This is fundamental for the approvalprocess of a package model by the competent authority (APAT) and the emission of thecorresponding certificate.

• Design of a new dual-purpose (storage and transport) package using the scale factors alreadydeveloped in the past for the CF66. The first instance will contain only the radium needles. Theobjective is to improve warehouse safety. Once the certificate of approval type B(U) is releasedby APAT, the transport modality will be studied, with the inclusion of cobalt and caesium sources.

• Obtaining authorisation to dismount the irradiation heads and their packing according to the IAEAradioactive sources catalogue.

• Once the management system for quality assurance is set up, application will be made to renewthe certificate of approval for CF6 and CF66 packaging.

• Qualification of industrial packaging (IP) of type A for transport of radioactive material.

• Contributions to the updating and revision of national and international transport regulations.

• Participation in the IAEA group for “Regulations for the Safe Transport of Radioactive Material”(Transport Safety Standards Committee).

C1 Radioactive Waste Management



C1.7 Disposal of Radioactive Waste

Artificial barriers for disposal units

The research regarded mainly cementitious materials and was carried out in collaboration with theDepartments of Structural Engineering and of Chemistry-Physics of Milan Polytechnic, EN.CO. Srl a well-known laboratory working with concrete and the Experimental Testing Laboratory of CESI-ISMES SpA.

The work was divided into three steps: identifying the optimal characteristics for structural concrete andgrout; investigating their properties through artificial aging tests; testing their efficiency in moduleprototypes.

A systematic study was performed to establish a reference mix-design, taking into account all possibleenvironmental attacks in Italy for a period of 300 years. A series of tests simulating the chemical andphysical attacks forecasted was then carried out on several specimens compounded with aggregates fromfour different Italian regions. In addition a suitable concrete mix-design was obtained through theANSI/ANS 16.1.1986 leakage tests, carried out on a 300x300-mm-wide concrete slab. Four full-scalemodule prototypes were then built, within the framework of the project on designing a final repository forlow-activity radioactive waste, from the same concrete mix and submitted to a waterproofing test at theIsmes Laboratory. The main object of the study was leaching, i.e., the selective transport of particlesoccurring in a material once water seepage is established, which can be activated by weathering of thematerial in the longer term. One prototype was also submitted to a seismic test of 1 g.

All the trials and tests confirmed the adequacy of the design and the materials chosen, and analysis of theachievements indicated ways to improve the module performance, e.g., by using fibre-reinforced concretewith new-generation additives and considering minor strength requirements under dynamics stresses.

The theoretical studies were completed by using a Monte Carlo simulation method based on the theory ofbranching stochastic processes. Also addressed was the issue of radionuclide transport through theartificial porous matrices constituting the engineered barriers: the complexity of the phenomena involved,augmented by the heterogeneity and stochasticity of the media in which transport occurs, renders classicalanalytical-numerical approaches scarcely adequate for a realistic representation of the system of interest.This approach, applied in the artificial porous matrices hosting the waste (near field), can certainly beusefully extended to study the phenomena of advection and dispersion of radionuclides in the natural rockmatrix of the host geosphere (far field).

and Advanced Nuclear Fuel Cycle Technologies

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D1 Advances in the IGNITOR Programme

The IGNITOR project has continued to progress both in the machine engineering design and relatedauxiliary systems and in the definition of the physics programme. The validity of the objectives of theIGNITOR programme and of its design solutions were reaffirmed by PH. Rebut at the latest EPSmeeting in Rome: i) in order to prove the scientific feasibility of relevant fusion reactors, burningplasmas with Q > 50 should be produced and studied; ii) copper magnets are the most convenientsolution for machines capable of reaching this objective; iii) experiments that do not include adivertor are the most efficient at producing the highest plasma currents with the best confinementparameters.

While ignition scenarios in IGNITOR have been extensively analysed in the past, plasma regimes andthe physics objectives that can be achieved when operating the machine at lower parameters havebeen further explored. In particular, at BT≅9 T, and Ip≅7 MA in the “extended limiter” configuration orIp≅6 MA in the double null configuration, in D-T plasmas, simulations performed with the JETTOcode show that the ideal ignition temperature can be attained. This is the point where the energyloss by Bremsstrahlung emission is compensated for by α-particle heating, and the density can beraised further without encountering a radiation barrier. These regimes require a certain amount of ioncyclotron resonance heating (ICRH) (5-8 MW at ~90 MHz). A parametric study of the powerdeposition profiles as a function of minority concentration, minority species, and frequency rangewas carried out by solving the 2D full wave equation, which describes the plasma-wave interaction,in toroidal geometry.

IGNITOR can operate with a double-null configuration at BT≅13 T, and Ip≅9 MA. On the basis ofrecent scalings, the power threshold to access the H-mode regime is considerably lower thanpreviously estimated. The expected plasma parameters were evaluated by using a 0-D model,which showed the existence of a relatively broad region of operation corresponding to Q ≅ 10, evenin the pessimistic case of rather flat density profiles. With more peaked profiles (e.g., n0/<n> ≅ 1.5),of the type being observed in some JET experimental data, the attainable plasma parameters arefound to improve considerably and values of Q much larger than 10 can be attained. The

construction of the four-barrel two-stage IGNITORpellet injector, in collaboration with the Oak RidgeNational Laboratory (ORNL), is nearly completed(fig. D1). The development of new, fast pulseshaping valves will make it possible to reach pelletvelocities of 4 km/s. The propulsion system, built inItaly, will be shipped to ORNL for final integrationwith the ORNL cryogenic and control systems, andpellet performance characterisation. The possibleapplication of the injector to JET has beenexplored, but other large existing devices are alsobeing considered.

The design of the full set of electromagneticdiagnostics for the IGNITOR experiment and theirintegration with the plasma chamber has beencompleted. Because the estimated neutron flux atthe first wall during high-performance dischargesis expected to cause a sensible, although


Fig. D1 – a) The ENEA Frascati sub-system of the Ignitor pellet

injector during testing at Criotec Impianti in Chivasso (Turin, Italy). b)

In-flight picture of a 3-mm D2 pellet, travelling at about 1.2 km/s


reversible, degradation of the inorganic insulator surrounding theconductors, an R&D program aimed at selecting insulatormaterials and fabrication procedures has been established. Twoprototype coils made of pre-insulated nickel wire immersed in amagnesium oxide weakly bonded powder were manufactured incollaboration with the University of Lecce (Italy) and SALENTEC.Vacuum tightness is provided by sintered alumina cases or byoxide ceramic composite wrapping layers.

An alternative diagnostic method for plasma position control hasbeen proposed: using a multilayer mirror as the dispersingelement for the soft x-ray radiation emitted from the plasma outerregion and a gas electron multiplier detector would allow theradiation from the lower or upper part regions to be diffracted tothe 2D detector placed outside one of the machine horizontalports, not in direct view of the plasma, to minimise thebackground radiation noise. This system should measure theplasma position and detect any movements with sufficient spatialand time resolution to be used for real-time control of the verticalposition.

The detailed design of the machine was completed during 2006,taking as reference the maximum performance scenario(11 MA/13 T/extended limiter). This design will be checked,referring to the double-null configuration at BT≅13 T, andIp≅9 MA.

The machine integration was also completed during the reportingyear, starting from the CATIA CAD of each component of themachine. As far as known, this is the first time that a detailed CAD-based integration has been performedfor such a complex apparatus. Figure D2 shows an example of the integration results.

D2 Ultra-Pure Hydrogen Production

Project (FIRB RBAU01K4HJ) funded by the Italian Ministry of Education, University andResearch. Long-term tests (more than one year) of thin-wall Pd-Ag permeator tubes produced at ENEAFrascati laboratories were carried out and the capability to produce ultra-pure hydrogen as well as thedurability of the permeators were demonstrated [D1].

A membrane process for producing hydrogen from hydrocarbon and alcohol reforming was developed[D2–D4] and a Pd-Ag multi-tube membrane reactor capable of producing 6 L/min of pure hydrogen was

147

Fig. D2 – a) Lateral and b) top views of the IGNITOR machine obtained from

integration of the CATIA CAD drawing of the detailed design of all the

components of the machine itself

a)

b)

[D1] S. Tosti et al., Long-term tests of Pd–Ag thin wall permeator tube, J. Membrane Sci. 284, 393–397 (2006)

[D2] S. Tosti et al., Procedimento a membrana per la produzione di idrogeno da reforming di composti organici, in particolare idrocarburi oalcoli, Domanda di brevetto per invenzione industriale n. RM2006A000102 del 01.03.2006

[D3] S. Tosti et al., Design and characterization of membrane reactors for producing hydrogen via ethanol reforming, ENEA Internal ReportFUS TN BB-R015 (2006)

[D4] S. Tosti et al., Pd membrane reactor design, Desalination 200, 676-678 (2006) Ref

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built (figs. D3 and D4). A lot ofexperimental work concerning themethanol and ethanol steam reformingreactions in Pd-Ag membrane reactorswas performed [D5–D7] and it wasdemonstrated that the membrane is ableto promote the reaction conversionbeyond the thermodynamic limit. Inparticular, at 450°C a high hydrogen yieldwas attained via the ethanol steamreforming on a Ru–based catalyst.Figure D5 reports the hydrogen yieldmeasured in the shell side of the Pd–Agmembrane reactor.

D3 Non-ITER Activities

Cryogenic testing of superconductive current leads for CERN. Since September 2004 ENEAhas been responsible for the cryogenic tests of the complete series of 6000 A and 13000 A LargeHadron Collider (LHC) HTS current leads, consisting of 333 units.The whole job also included, as afirst step, testing of the pre-series lead production, manufactured and assembled at CERN.

The main campaign of tests involving the current leads produced by the BINP laboratory, RussianFederation (6 kA) and by CECOM, Italy (13 kA), started in the second half of 2005, and proceededthroughout 2006, thereby meeting the tight time schedule requested by CERN.

Thanks to ENEA’s dedicated measurement facility, characterised by a high-precision signalacquisition system, the results showed very good reproducibility of both the electrical and thethermo-hydraulic performances of the leads in LHC-relevant operating conditions and all the testedsamples fully met the requirements of the CERN technical specifications.

The measurement campaign is foreseen to be completed within the first months of 2007.


Miscellaneous

Fig. D3 – The multi-tube membrane reactor

Fig. D4 – Particulars of

the flange supporting

the Pd–Ag permeator

tubes

She

ll si

dehy

drog

en y

ield

(%

) 100

80

60

40

20

00 5 10 15 2520

Feed flow rate (g h-1)

200k Pa

150k Pa

Fig. D5 – Shell-side hydrogen percent yield at 450°C and

feed molar ratio H2O/EtOH=13


D4 Condensed Matter Nuclear Science

Material science and calorimetry. Cold fusion matter, now more properly renamed “condensed matternuclear science”, has been debated over for the last two decades [D8]. Prestigious institutions have beenworking in this field and some have cooperated successfully. It was discovered [D9, D10] that thephenomenon of excess power production was a threshold effect occurring only if the average deuteriumconcentration in the palladium lattice was not less than 0.9 (atomic fraction). Studies performed at ENEAFrascati highlighted the fact that the high loading of deuterium in the lattice was not reproducible whenusing commercial palladium. Hence, a wide material-science study was carried out to produce a metal witha proper metallurgical structure, capable of giving a very high deuterium concentration duringelectrochemical loading.

Under contract agreements ENEA delivered cathodes prepared with such a particular palladium to SRIInternational (California USA) and Energetics Ltd. (US company with a research centre in Israel). Areasonable level of transferred reproducibility was achieved by the three groups and this was one of thereasons for promoting a two-phase research project with government funding in the USA to revisit the“cold fusion effect”. ENEA was involved in the programme as ENEA cathodes were selected for theresearch. During the first phase SRI International was charged with replicating the results obtained withENEA’s cathodes and with the calorimeters used by Energetics Ltd. Phase 1 was concluded at thebeginning of 2007 with results well above the objectives defined by the US Government referees, andcontinuation of the project towards Phase 2 was approved. In the second phase, the US Naval ResearchLaboratory is also involved in replicating the experiments.

The Italian Ministry of Economic Development (MSE) supported a two-year project (Produzione di Eccessodi Potenza in Metalli Deuterati) to improve the material science study and to gain an enhanced signal/noiseratio. Material science studies have been extended tosurface physics aspects and to interphase physics, with theinvolvement of the University of Rome La Sapienza. TheItalian project began in January 2006 and overlapped Phase1, so the two projects have been developed in parallel.During this period both ENEA and SRI International gained areproducibility not less than 60% with a signal/noise ratio wellabove the measurement uncertainty. Figure D6 shows theENEA flow calorimeters; figure D7 the excess powerobserved during the experimental campaign performed atENEA (experiment L17) and figure D8 the increase in theelectrolyte temperature associated with the excess.

The power gain was 500% with an input and an outputpower of 0.1 W and 0.6 W, respectively (measurement

149

[D5] F. Gallucci et al., Methanol and ethanol steam reforming in membrane reactors: An experimental study, Int. J. Hydrogen Energy (2006),doi: 10.1016/j.ijhydene.2006.11.019

[D6] A. Basile et al., Co-current and counter-current modes for methanol steam reforming membrane reactor: Experimental study, CatalysisToday 118, 237–245 (2006)

[D7] A. Basile et al., The pressure effect on ethanol steam reforming in membrane reactor: experimental study, Desalination 200, 671–672(2006)

[D8] M. Fleishmann and S. Pons, J. Electroanal. Chem. 261, 301 (1989).

[D9] M. McKubre et al., Excess power observation in electrochemical studies of the D/Pd system; the influence of loading, Proc. 3rd Inter.Conference on Cold Fusion (Nagoya 1992) p. 5

[D10] K. Kunimatsu et al., Deuterium loading ratio and excess heat generation during electrolysis of heavy water by a palladium cathode in aclosed cell using a partially immersed fuel cell anode, Proc. 3rd Inter. Conference on Cold Fusion (Nagoya 1992), p. 31 R

efer

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sFig. D6 – Calorimeter room at ENEA Frascati

uncertainty ±20 mW). Of the many experimentsperformed with hydrogen, not one has producedexcess power.

Figure D7 shows that during the excess the inputpower decreases due to the power supplyoperating mode (galvanostat) because the strongexcess of power (up to 620 mW) caused thetemperature of the electrolyte to increase(fig. D8), which was responsible for reducedelectrolyte resistivity and also of the cathodeinterfacial impedence, so a lower voltage wasrequired to maintain the set point current. Theconsequence was a reduction in input powerduring the burst. The conclusion was 620 mW ofoutput with an input of 125 mW, hence an outputgain of 500%.

Similar results were observed with ENEA’scathodes at SRI International. The statisticsrevealed that the cathode lots producing excesspower at ENEA had, in general, the samebehaviour at SRI. On the contrary, any lot that didnot produce excess power at ENEA did notproduce it at SRI International either.

Despite the very high excess of power observed, the most relevant point is the energy gainassociated with power gain. Energy gains up to some MJ have been observed in ENEA’s cathodes(6.25 keV per atom into the electrode). Energy gain is a crucial point because a large amount of theenergy produced cannot be simply justified as a chemical effect if sharing the energy between allthe atoms embedded in the electrode produces, as already reported, an energy per atom well abovea few eV. A possible explanation is that there is a mechanism accumulating energy in the system ata very slow rate so that no negative power gain is detected by the calorimeter because outside thedetection limits. In the case of a fast energy release, as in the Wigner effect, an apparent excess ofpower would be revealed by the calorimeter; however, such an energy gain would have to be of theorder of a few eV/atom in order to be ascribed to a chemical effect, which is in contrast with theexperimental observations.

The amount of energy gain and the occurrence of the effect with deuterium and not with hydrogenpoint in the direction of a nuclear fusion reaction between two deuterons producing, in the lattice,4He and heat. This is in agreement with preliminary measurements of 4He [D11-D14], which revealan increase in the concentration above the ambient level, consistent with the energy gain.

In 2005 a very positive co-operation was started in the field of materials science with the MaterialsBranch of the Naval Research Institute of Washington DC. This ongoing research activity is fundedby the Office of Naval Research Global (ONRG), London UK, and an important experiment hasalready been carried out at the Brookhaven National Laboratory, USA. X-ray diffraction wasperformed during electrochemical loading of cathodes prepared at ENEA in order to study thepalladium hydride (deuteride) in the so far unexplored region of loading above H(D)/Pd>1. Theexperiment was concluded successfully by collecting more that 240 spectra.


Miscellaneous

0.6

0.4

0.2

0200000 240000 280000

Wout

Win

Time (s)

Pow

er (

W)

200000 240000 280000

Tbox

Tcell

30.0

29.0

28.0

27.0

26.0

25.0

Time (s)

Tem

pera

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(°C

)Fig. D7 – Input and output (upper curve) power evolution in

the experiment L17

Fig. D8 – Electrolyte temperature evolution:

temperature increase is well correlated with the

excess of power


The support received by MSE has made it possible to extendthe material science study by performing a systematiccharacterisation of the surface of cathodes on the basis ofthe atomic force microscopy (AFM) and scanning electronmicroscopy (SEM) analyses.

Microscopic characterisation of finished electrodesbefore electrolysis. Microscopic characterisation of theelectrodes was performed in order to correlate thecharacteristics of the cathodes before loading and theexcess power production during electrochemical deuteriumloading.

Three cathodes produced from three different lots of roughmaterials, but with similar rolling, thermal annealing andchemical etching processes were analysed and showeddifferent behaviour in heat production. The deuterium loadingwas fairly similar in all three samples and above the threshold(D/Pd>0.9). The nominal purity of the rough foils is 99.95 forL25b and L35 and 99.98 for L40.

SEM analysis. SEM analysis showed differentcharacteristics in grain size distribution, grain boundaryshape and surface morphology. Figure D9 reports acomparison of the SEM images of the three samples. SampleL40 shows an average grain size smaller than the other twosamples; sample L25, the larger dimensions of the grains.Furthermore, in L40 some of the grain boundaries have aparticular “crest-like” shape, while in L25b and L35 theboundaries have the more usual “valley-like“ shape. Thesecharacteristics were checked by AFM recording of thesurface profile as it is well known that SEM images can bemisleading in identifying peak or kink features.

The SEM and AFM analyses revealed some differences in thesamples. A specific work devoted to identifying thecorrelation between excess of heat and the characteristics of the samples, now in progress, should leadto identification of the characteristics of the rough material capable of producing Pd cathodes with afurther increasing of the reproducibility of excess power production.

151

a)

100 µm EHT=20.00 kV Signal A=CZ BSDWD=9.5 mm Mag=200x

L25b

b)

EHT=20.00 kV Signal A=SE1 WD=10.0 mm Mag=200x

100 µm

L35

c)L40

100 µm EHT = 20.00 kV Signal A=SE1WD = 10.0 mm Mag=200x

Fig. D9 – SEM images of samples L25b a), L35 b)

and L40 c)

[D11] V. Violante et al., Some recent results at ENEA, Proc. XII Inter. Conference on Cold Fusion (Yokohama 2005), p. 117

[D12] D. Gozzi et al., J. Electroanal. Chem. 452, 253 (1998)

[D13] M. McKubre et al., The emergence of a coherent explanation for anomalies observed in D/Pd and H/Pd systems: evidences for 4He and3H production, Proc. VIII Inter. Conference on Cold Fusion (Lerici 2000), p 3

[D14] M. Miles et al., J. Electroanal. Chem. 346, 99 (1993) Ref

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Coordinamento TrasferimentoTecnologico

Francesco De Marco

Nucleo di Agenzia

Paola Batistoni

Coordinamento Funzionale

Giovanni Coccoluto

Unità Supporto Tecnico Gestionale FUS

Nicola Manganiello

Unità Supporto Tecnico Gestionale RADPasquale Di Giamberardino

*

*

*

*EURATOM - ENEA Association

December 2006

DIREZIONEAlberto Renieri


Sezione Sorgenti Radiazioni e Applicazioni diRadiazioni Ionizzanti

Armando Festinesi

Sezione Sistemi Nucleari Innovativi e Chiusura CicloNucleare

Renato Tinti

Laboratorio Caratterizzazione Rifiuti Radioattivi

Natale Sparacino

Sezione Esercizio Impianti - Saluggia

Corrado Kropp a.i.

Sezione Esercizio Impianti - Trisaia

Corrado Kropp a.i.

Sezione Fisica della Fusione a ConfinamentoMagnetico

Alberto Renieri a.i.

Sezione Tecnologie della Fusione

Aldo Pizzuto

Sezione Ingegneria Elettrica ed Elettronica

Alberto Coletti

Sezione Gestione Grandi Impianti Sperimentali

Giuseppe Mazzitelli

Sezione Superconduttività

Antonio della Corte

Gruppo Fisica e Tecnologie del ConfinamentoInerziale

Carmela Strangio

Sezione Ingegneria Sperimentale

Gianluca Benamati

*

*

*

*

*

*

*Sezione Esercizio Impianti - Casaccia

Corrado Kropp a.i.

Abbre

via

tions a

nd A

cro

nym

s

ACP activated corrosion product

AFM atomic force microscopy

ALE abrupt large-amplitude event

ALISIA Assessment of Liquid Salts for Innovative Applications

APSA ageing probabilistic safety assessment

AS angular scanning

ASDEX Axisymmetric Divertor Experiment - Garching - Germany

ASDEX-U Axisymmetric Divertor Experiment Upgrade - Garching - Germany

ASTEX Advanced Stability Experiment

BA Broader Approach

BAE beta-induced Alfvén eigenmode

BNCT boron neutron capture therapy

BOC beginning of cycle

CD current drive

CDP collector depressed potential

CEA Commissariat à l’Energie Atomique - France

CERN Organisation Europeénne pour la Recherche Nucléaire- Geneva

CFC carbon fibre composite

CHF critical heat flux

CICC cable-in-conduit conductor

CIRTEN Consortium for Research in Nuclear Technologies

CMS common manipulator system

CNR Consiglio Nazionale delle Ricerche - Italy

COMPASS-D is a highly flexible, medium-sized tokamak - Culham

CODAS control and data acquisition system

CPS coolant purification system

CPS capillary porous system

CRPP Centre de Recherches en Physique des Plasmas - Villigen - Switzerland

CS central solenoid

CSU Close Support Unit

CT/CAT computerized (axial) tomography

Cyric Cyclotron and Radioisotope Centre - Tohoku University - Japan

CVD chemical vapour deposition

DAS data acquisition system

DEMO demonstration/prototype reactor

DCLL dual coolant lithium-lead

DIS data one-step

DISCORAP Dipoli Super Conduttori Rapidamente Pulsati (INFN) - Frascati

DL dome liner

DRP Divertor Refurbishment Platform - ENEA - Brasimone

DIII-D Doublet III - D-shape. Tokamak at General Atomics - San Diego - USA

DTL drift tube linac

DVT divertor vertical target

DW drift waves

EAF European Activation File

EBSD electron backscattering diffraction

EC electron cyclotron

ECCD electron cyclotron current drive



ECH electron cyclotron heating

ECR electron cyclotron resonance

ECRH electron cyclotron resonance heating

EC WGB electron cyclotron wave Gaussian beam

ECT/TCT emission & transmission tomography

ECT/TCT electrical capacitance tomography/transmission computer tomography

EDA Engineering Design Activities

EDS electron dispersion spectroscopy

EFDA European Fusion Development Agreement

EFIT European facility on an industrial-scale transmuter

EFF European fusion file

EISOFAR European Innovative Sodium-Cooled Fast Reactor

ELD electron Landau damping

ELM edge localised modes

ELSY European lead-cooled system

em electromagnetic

EN-TRAP European Network of Testing Facilities for the Quality Checking of Radioactive Waste Packages

EOC end of cycle

EOL end of life

EP Enhanced Programme (JET)

EPM energetic particle mode

ETD European Transmutation Demonstrator

EUROPART European Research Programme for the Partitioning of Minor Actinides

EUROTRANS European Transmutation

FC fission chamber

FCS flux-core spheromak

FDB fuel dissolution basket

FEB fast electron bremsstrahlung

FEM finite-element method/model

FIGEX Fast Ion Generation Experiment

FMEA failure mode and effect analaysis

FMECA Failure Mode, Effects, and Criticality Analysis

FNG Frascati neutron generator - ENEA

FNS Fusion Neutronics Source - JAERI - Japan

FPS fuel pin simulator

FRTC fast ray tracing code

FTU Frascati Tokamak Upgrade - ENEA

FWHM full width at half maximum

FWP first-wall panel

FZK Forschungszeuntrum - Karlsruhe - Germany

GAM geodesic acoustic mode

GNEP Global Nuclear Energy Partnership

GRTN National Grid Regulator

GSI Gesellschaft fuer Schwerionenforschung - Darmstadt, Germany

GSSR Generic-Site Specific Safety Report

HCLL helium-cooled lithium-lead

HCPB helium-cooled pebble bed

HEBT high-energy beam transport

HHFT high heat flux testing

HLM heavy liquid meta

155

HL-1Ml Circular cross section tokamak modified from HL-1 - Centre for Fusion Science - China

HRP hot radial pressing

HRTS high-resolution Thomson scattering

HS heat source

HTS high-temperature superconductor

HX heat exchanger

IAEA International Atomic Energy Agency - Vienna - Austria

I&D instrumentation and control

IBW ion Bernstein wave

ICE Integral Circulation Experiment

ICRH ion cyclotron resonance heating

IDM ITER Documentation Management

IE Institute for Energy - Petten - the Netherlands

IEA International Energy Agency

IFE inertial fusion energy

IFMIF International Fusion Materials Irradiation Facility

IMF inert matrix fuel

INFN-LNL Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro

INTD International Near-Term Deployment

IP industrial packaging

IRIS International Reactor Innovative and Secure

ISPESL Institute of Occupational Safety, Health and Prevention

ISOCS In-situ object counting system

ITASE International Trans Antarctic Scientific Expedition

ITB internal transport barrier

ITER International Thermonuclear Experimental Reactor

ITG ion temperature gradient

IVT inner vertical target

IVVS in-vessel viewing and ranging system

JAEA Japan Atomic Energy Agency - Japan

JET Joint European Torus - Abingdon - U.K.

JIPPT-IIU Japanese Institute of Plasma Physics Torus-II Upgrade

JRAs Joint Research Activities

JRC Joint Research Centre - Ispra - Italy

JT-60U JAERI Tokamak 60 Upgrade, Naka, Japan

KH Kelvin Helmholtz

KIZ Karlsruhe Isochronous Cyclotron

LANL Los Alamos National Laboratory

LBC liquid bismuth cathode

LBE lead bismith eutectic

LCA life cycle assessment

LED light emitting diode

LFR Lead-Cooled Fast Reactor

LH lower hybrid

LHC Large Hadran Collider (CERN)

LHCD lower hybrid current drive

LHW lower hybrid wave

LIDAR-TS laser imaging detection and ranging - Thomson scattering

LLL liquid lithium limiter


Abbreviations and


LLRN long-lived radionuclides

LNL Legnano National Laboratory

LOFT loss-of fluid test

LWR light-water reactor

MA minor actinides

MARFE multifaceted asymmetric radiation from the edge

MAST Mega Ampère Spherical Tokamak

MHD magnetohydrodynamic

MIUR Italian Ministry of Higher Education and Research

MOD metal-organic deposition

MSE motional Stark effect

MSE Italian Ministry of Economic Development

NAR Nuclear Analysis Report

NAs Networking Activities

NBI neutral beam injection

NEA Nuclear Energy Agency (Paris, France)

NEA standing committees (NSC - Nuclear Science; NDC - Nuclear Development; CSNI - Safety of Nuclear Installation; RWMC- - Radioactive Waste Management; CRPPH - Radiation Protection and Public Health)

NETL Nuclear Engineering Teaching Laboratory - Texas - U.S.A.

NNB negative neutral beam

NTA neutron test area

NTM neoclassial tearing mode

NRG Nuclear Research Counsultancy Group - Petten - The Netherlands

OCS oxygen control system

ODE ordinary differential equation

ONRG Office of Naval Research Global

ORE occupational radiation exposure

ORNL Oak Ridge National Laboratory - Tennessee - U.S.A.

OVT outer vertical target

PATEROS Partitioning and Transmutation European Roadmap for Sustainable Nuclear Energy

PCB polychlorobiphenyls

PBC pre-brazed casting

PD power density

PDE partial differential equation

PDI parametric decay instability

PET pin expansion tool

PF poloidal field

PFC plasma-facing component

PFCT plasma-facing component transporter

PFW primary first-wall

PIE postulated initiating event

PIT powder-in-tube

PLD pulsed-laser deposition

PMT photomultiplier tube

PPCS Power Plant Conceptual Studies

PRA probabilistic risk assessment

PRF permeation reduction factor

PRHH preliminary remote handling handbook

PSI Physiological Strain Index

PWR pressurised water reactor

157

Acronyms

QA quality assurance

RABiTS rolling-assisted biaxially texture of substrate

RACE Reactor-Accelerator Coupling Experiments

RAPHAEL Reactor for Process Heat, Hydrogen and Electricity Generation

RD rolling direction

rf radiofrequency

RFQ radiofrequency quadrupole

RFX Reversed Field Pinch Experiment - Padua - Italy (Association EURATOM-ENEA)

RH remote handling

RO responsible officer

RT room temperature

S/A subassembly

SCD single crystal diamond

SEM scanning electron microscopy

SFE stacking fault energy

SGS segmented gamma scanner

SOL scrape-off layer

SP screw pinch

SPES Study for the Production of Exotic Species

SRWGA SEA radioactive-waste gamma analyser

SSC solid steel cathode

SSQLFP steady-state quasi-linear Fokker-Planck

ST spherical torus

TAa Transnational Access Activities

TAE toroidicity-induced Alfvén eigenmode

TALDICE Talos Dome Ice

TBM test blanket module

TES tritium extraction system

TEPC tissue-equivalent proportional counters

TEXTOR Torus Experiment for Technology Oriented Research. Tokamak at Jülich Germany (Association EURATOM –FZJ)

TFA trifluoroacetate

TFAS toroidal field advaced strands

TFC toroidal field power

TIG tungsten inert gas

TITG trapped ion ITG

TOFOR time-of-flight neutron spectrometer optimized for high counting rate

TPR tritium permeation rate

TRADE TRIGA Accelerator-Driven Experiment - ENEA- Casaccia

TS Thomson scattering

TUCN Technical Universitry of Cluj-Naoica - Romania

TUD Technical University of Dresden - Germany

UCI University of California at Irvine - Usa

UKAEA United Kingdom Atomic Energy Agency

UT University of Texas - USA

VELLA Virtual European Lead Initiative

VDS vent detritiation system

VHTR Very High Temperature Reactor


Abbreviations and


VMS vertical module segmentation

VSM vibrating sample magnetometer

VTA vertical target assembly

WKB Wenzel, Kramer, Brillouin code

XRD x-ray diffraction

ZF zonal flow

ZFC zero field cooling

159

Acronyms

Cover picture: The six BNC cables andPiccolo–Micromegas assemby inside the TRIGAreactor

See http://www.fusione.enea.it for copy of this report

This report was prepared by the Scientific Publications Office from contributions provided by the scientific andtechnical staff of ENEA’s Nuclear Fusion and Fission, and Related Technologies Department.

Scientific editors: Paola Batistoni, Adriana Romagnoli, Gregorio VladDesign and composition: Marisa Cecchini, Lucilla Crescentini, Lucilla GhezziArtwork: Flavio MigliettaEnglish revision: Carolyn Kent

Tel: +39(06)9400 5016 Fax: +39(06)9400 5015e-mail: [email protected]

Published by:

ENEA - Nucleo di AgenziaEdizioni Scientifiche,Centro Ricerche Frascati,C.P. 6500044 Frascati, Rome (Italy)

2006

2006

PROGRESS REPORT Nuclear Fusion and Fission, and Related Technologies Department

ITALIAN NATIONAL AGENCY FOR NEW TECHNOLOGIES ENERGY AND THE ENVIRONMENT

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Documents

2006 PROGRESS REPORT - ENEA - Fusione · European Lead-Cooled Fast System 104 Very high temperature reactor 106 B1.3 Nuclear Safety 107 Code validation and accident analysis 107 Severe