Annual Report of the Association EURATOM/CEA 2003

Annual Report of the Association EURATOM/CEA

2003(full report)

Compiled by : Ph. MAGAUD and F. Le VAGUERES

ASSOCIATION EURATOM/CEADSM/DRFC

CEA/CADARACHE 13108 Saint-Paul-Lez-Durance (France)

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FUSION TECHNOLOGY

Annual Report of the Association CEA/EURATOM

2003 (full report)

Compiled by : Ph. MAGAUD and F. LE VAGUERES

ASSOCIATION CEA/EURATOM DSM/DRFC

CEA CADARACHE 13108 Saint-Paul-Lez-Durance (France)

Tél. : 33 - 4 42 25 46 59 Fax : 33 - 4 42 25 64 21 e-mail : [email protected] Web : http://www-fusion-magnetique.cea.fr

This report is also available on-line at : http://www-fusion-magnetique.cea.fr

Cover : Exploded view of the Helium Cooled Lithium Lead (HCLL) breeding blanket concept.

- I -

CONTENTS

INTRODUCTION ................................................................................................................................ 1

EFDA TECHNOLOGY PROGRAMME ........................................................................ 3

Physics Integration Heating and Current Drive CEFDA01-645 Support to neutral beam physics and testing 1 - Modelling, design and R&D on the SINGAP accelerator ..................................... 5 CEFDA01-646 Support to neutral beam physics design and testing 2 -

Development on negative ion sources ................................................................... 9 CEFDA02-676 ICRF antenna and system design - Internal matching ........................................... 13 CEFDA02-689 Lower hybrid system design (Mode filters and RF window) ................................ 17 CEFDA03-1047 First ITER NB injector and the ITER NB test facility: Design ............................. 19 TW1-TPH-ICRANT ICRF antenna and vacuum transmission line development - Design & Manufacturing of a CW ICRF high power test rig and testing of next step antenna prototype components .............................................................................. 23 Diagnostics CEFDA02-1003 TW2-TPDS-DIASUP4 : Support to ITER diagnostic design: Bolometry, thermography, motional stark effect and polarimetry ......................... 25 TW2-TPDS-DIADEV-D01 Development of diagnostic components: Long pulse integrator ............................ 29 TW2-TPDS-DIADEV-D02 Development of diagnostic components: First mirror study .................................. 31

Vessel-In Vessel Vessel-Blanket and Materials CEFDA03-1067 TW3-TVM-MDB : Rules for design, fabrication and inspection - Establishment and maintenance of a material database ......................................... 35 TW1-TVV-HIP Improvement of HIP fabrication techniques .......................................................... 37 TW1-TVV-ONE Optimisation of one step SS/SS and SS/CuCrZr HIP joints for retainment of CuCrZr properties ...................................................................... 41

- II -

TW2-TVB-HYDCON Development of an industrial cutting and welding tool for fabrication and maintenance of the hydraulic connector ......................................................... 45 TW2-TVV-DISMIT Evaluation of methods for the mitigation of welding distortions and residual stresses in thick section welding ........................................................ 49 TW2-TVV-ROBOT Dynamic test rig for Intersector Welding Robot (IWR) for VV sector field joining ..................................................................................... 51 TW3-TVM-JOINT Characterization of the CuCrZr/SS junction strength for different blanket manufacturing conditions ...................................................................................... 53 TW3-TVV-DISFREE Further development of laser conduction and cryogenically - produced distortion - free welding ......................................................................................... 57 TW3-TVV-ROBASS Long detection range seam tracker ........................................................................ 59 TW3-TVV-UTDYNAM Development of dynamic phased array techniques ................................................ 61 Plasma Facing Components CEFDA01-585 Monitoring and analysis of thermal fatigue testing of divertor prototypes - 200 kW electron beam gun test .............................................................................. 65 CEFDA02-583 Destructive examination of primary first wall panels and mock-ups ..................... 69 CEFDA03-1029 TW3-TVB-JOINOP: Optimization of Be/CuCrZr joints for primary first wall panels .................................................................................. 73 CEFDA03-1051 TW4-TVD-ACCEPT: Acceptance criteria for the ITER divertor ......................... 75 CEFDA03-1077 TW3-TVB-INMOCK: Fabrication of primary first wall mock-ups for in-pile experiments ........................................................................................... 79 DV4.3 Optimization and manufacture of HHF components - Study of flat tile cascade failure possibility for high heat flux components .......... 83 TW0-T438-01 Development and testing of time resolved erosion detecting technics - Development and implementation of an erosion redeposition diagnostic by means of speckle interferometry ....................................................................... 87 Remote Handling TW0-DTP/1.1 Carrier and bore tools for 4" bent pipes ................................................................. 91 TW1-TVA-BTS Bore Tools Systems (BTS) .................................................................................... 95 TW1-TVA-MANIP In vessel dexterous manipulator - Dynamic identification and monitoring capabilities .................................................................................... 99 TW1-TVA-RADTOL Radiation tolerance assessment of standard electronic components for remote handling ............................................................................................... 103 TW2-TVR-IVP Prototypical manipulator for access through IVVS penetrations (IVP) TW3-TVR-IVV and IVVS deployer ................................................................................................ 109 TW3-TVR-RADTOL Radiation tolerance assessment of standard electronic components for remote handling ............................................................................................... 113

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Magnet Structure CEFDA03-1015 TW2-TMSM-COOLIN: Mock-ups for the TF and CS terminal regions and cooling inlets ................................................................................................... 117 M50 Conductor R&D - Development of NbTi conductors for ITER PF coils ............... 119 TW1-TMC-CODES Design and interpretation codes - Determination of thermohydraulic properties of cable-in-conduit conductors with a central channel .......................... 123 TW1-TMC-SCABLE Cable and conductor characterization - Determination of critical properties and losses of superconducting strands and cables for fusion application .............. 127 TW1-TMS-PFCITE Poloidal Field Conductor Insert (PFCI) ................................................................. 129 TW2-TMST-TOSKA TFMC testing with the LCT coil ............................................................................ 131 TW3-TMSC-ELRES Experimental assessment of the effect of electrical resistances on the V-I characteristics of superconductive cables ............................................. 135

Tritium Breeding and Materials Breeding Blanket Water Cooled Lithium Lead (WCLL) blanket TW1-TTBA-001-D03 TBM adaptation to next step machine - Adaptation of mechanical performances to ITER specifications .................................................. 139 Helium Cooled Pebble Bed (HCPB) blanket TW2-TTBB-002b-D01 Blanket manufacturing techniques - First wall HIPing with open channels .......... 145 TW2-TTBB-002b-D03 Blanket manufacturing techniques - Procurement and quality control of Li2TiO3 pebbles ................................................................................................. 149 TW3-TTBB-002-D02 Blanket manufacturing techniques - Optimisation for cost reduction of fabrication process of Li2TiO3 pebbles by extrusion in the case of the production of 6Li enriched pebbles ............................................ 153 Helium Cooled Lithium Lead (HCLL) blanket TW2-TTBC-001-D01 Helium cooled lithium lead - TBM design, integration and analysis - Blanket system design and analysis - Integration and testing in ITER .................. 157 TW2-TTBC-002-D01 Blanket manufacturing techniques - Fabrication processes for HCLL and HCPB TBMs .................................................................................. 163 TW2-TTBC-002-D03 Blanket manufacturing techniques - Thermomechanical tests on HCLL blanket mock-ups .................................................................................. 167 TW2-TTBC-005-D02 Helium cooled lithium lead - TBM system detailed safety and licensing ............. 169

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Structural materials development Reduced Activation Ferritic Martensitic (RAFM) steels TW1-TTMS-002-D16 Mechanical properties of diffusion bonded welds (RAFM/RAFM HIP joint) ...... 173 TW1-TTMS-003-D12 Stress corrosion cracking behaviour of Eurofer'97 in water with additives ........... 175 TW2-TTMS-001b-D02 Irradiation performance - Neutron irradiation to 35-70 dpa at 325°C and PIE ............................................... 179 TW2-TTMS-004a-D01 Eurofer: Powder HIP processing and specification ............................................... 183 TW2-TTMS-004a-D04 Eurofer: Fusion welds development - Test blanket module's welding procedures: assembly of the horizontal cooling plates to the vertical cooling plates with the plasma arc welding process ..................................................................... 187 TW2-TTMS-004b-D01 Tubing process qualification - Advanced process development and testing for the production of TBM's cooling channels ...................................................... 191 TW2-TTMS-004b-D02 Tubing process qualification - Processing of high quality welds according to TBM design ...................................................................................... 195 TW2-TTMS-005b-D03 Rules for design, fabrication and inspection - Fracture mechanics assessments of TBM's ............................................................ 199 TW2-TTMS-005b-D05 Rules for design, fabrication and inspection - Collection, qualification and presentation of mechanical properties of Eurofer ........................................... 203 TW2-TTMS-005b-D09 Rules for design, fabrication and inspection - Material design limits for TBM’s application: Update and completion of Appendix A for Eurofer steel including new heats .................................................................... 205 TW3-TTMS-006-D05 High performance steels - Microstructural investigation to explain the effect of the mechanical alloying on the low impact properties of the ODS steels .......... 207 TW3-TTMS-007-D02 Modelisation of irradiation effects - Ab-initio calculations of the system Fe-He ............................................................................................... 211 Advanced materials TW2-TTMA-001a-D10 SiC/SiC ceramic composites - Study of a multi-scale model to simulate the mechanical behaviour of SiCf/SiC composite ............................... 215 TW3-TTMA-001-D04 Irradiation of SiC/SiC ceramic composites and tungsten alloys ............................ 217 TW3-TTMA-002-D04 Neutron source TW3-TTMI-001-D01 IFMIF, accelerator facility - Development of critical accelerator components: Electron Cyclotron Resonance (ECR) source/ Low Energy Beam Transport (LEBT) system ....................................................... 221 TW3-TTMI-001-D03 IFMIF, accelerator facility - Analysis of possible alternatives developed in the Key Element technology Phase (KEP), to the reference design of accelerator system ........................................................ 225 TW3-TTMI-001-D05 IFMIF, accelerator facility - Engineering design outline, High Energy Beam Transport (HEBT) .................................................................. 229

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Safety and Environment TW1-TSS-SEA3.5 In vessel hydrogen deflagration/detonation analysis ............................................. 233 TW1-TSS-SEA5 Validation of codes and models - EVITA PAX ITR 2 - TW3-TSS-SEA5.5-D03 Third set of calculation on the EVITA facility (cryogenic complementary tests) ........................................................................... 235 TW1-TSW-002 Waste and decommissioning strategy .................................................................... 237 TW3-TSS-SEA5.3 Ice formation on cryogenic surfaces ...................................................................... 239

System Studies Power Plant Conceptual Studies (PPCS) TW1-TRP-PPCS1-D02b Model A (WCLL): Irradiation effects assessment for the new design TW1-TRP-PPCS2-D02b of a water cooled divertor ...................................................................................... 241 TW2-TRP-PPCS15-D03 PPCS - Environmental assessment ........................................................................ 245 Socio-economics studies TW1-TRE/FPOA Fusion and the public opinion: Public acceptance of the siting of ITER at Cadarache ........................................................................ 247

ITER Site Preparation CEFDA02-663 ITER cryoplant and cryo-distribution design ........................................................ 251 CEFDA02-1011 TW2-MAG-COM: Magnetic - Field compatibility of components and devices for low voltage electrical distribution boards ..................................... 255

Design Support and Procurement CEFDA02-684 TW2-TDC-MAGSPEC2: Support to procurement specifications for magnet system .................................................................................................. 257

JET Technology Physics Integration Heating Systems CEFDA02-670 JET-EP: Contribution to ICRH components design and testing ............................ 259 CEFDA03-1031 JET-EP-ICRH: Contribution to ICRH components antenna limiter ...................... 263 Diagnostics CEFDA01-624 Diagnostics enhancement - CEFDA03-1044 IR viewing project management and implementation ........................................... 265

- VI -

Vessel-In Vessel Plasma Facing Components JET-EP-DHD-01 JET EP MKII-HD Divertor - Tiles chamfering and power handling ..................... 269 JW2-EP-DHD JW0-FT-3.1 Internal PFC components behaviour and modelling .............................................. 273 Safety and Environment JW3-FT-3.14 Laser tritium decontamination ............................................................................... 277 JW0-FT-2.5 Dedicated procedures for detritiation of steel and graphite ................................... 281

Heating Systems Technology Project TW3-THHE-CCGDS1 Coaxial cavity gyrotron and test facility - Design, support to the industrial development and preparation of the technical specifications ...................................................... 283 TW3-THHI-GTFDS1 Fusion diacrode, ICRF generator, IC power supply and IC test facility - Design, support to industrial development and preparation of the technical specifications ................................................................................ 285

UNDERLYING TECHNOLOGY PROGRAMME ................................................ 289

Vessel-In Vessel Plasma Facing Components UT-VIV/PFC-HIP Improvement of the reliability, performance and industrial relevancy of HIP fabrication processes for PFC components ................................................ 291 UT-VIV/PFC-NanoSic Nanocrystalline silicon carbide (SiC) - Optimization of the preparation of nano-SiC ......................................................... 295 UT-VIV/PFC-W/Coat Development of thick W CVD coatings for divertor high heat flux components .................................................................................................... 299 Remote Handling UT-VIV/AM-Actuators Remote handling techniques - Advanced technologies for high performances actuators ............................................................................ 303 UT-VIV/AM-Hydro Remote handling techniques - Technologies and control for hydraulic manipulator ...................................................................................... 305 UT-VIV/AM-ECIr Remote handling techniques - Radiation effects on electronic components .......... 309 UT-VIV/AM-vacuum Remote handling techniques - Technologies for vacuum and temperature and magnetic field conditions for remote handling systems .................................. 313

- VII -

Tritium Breeding and Materials Breeding Blanket UT-TBM/BB-He Helium components technology - Available technology and proposition of tests ....................................................... 317 Materials Development Structural Materials UT-TBM/MAT-LAM/DBTT Influence of the martensite morphology on the DBTT of Eurofer steel ................ 321 UT-TBM/MAT-LAM/DBTTpred Prediction of the DBTT of martensitic steels by neural networks ......................... 325 UT-TBM/MAT-LAM/Opti Development of new RAFM steels with regard to creep properties ...................... 329 UT-TBM/MAT-Modpulse Pulsed irradiation of the martensitic alloy Eurofer - Preparation of samples for irradiations by krypton ions ............................................................................. 333 UT-TBM/MAT-ODS Development of forming and joining technologies for ODS steels ....................... 337

Safety and Environment UT-S&E-LASER/DEC Laser decontamination: Tritium removal................................................................ 341 UT-S&E-LiPbwater Modelling of the interaction between lithium-lead and water using the SIMMER-III code ................................................................................... 345

APPENDIX 1 : Directions contribution to the fusion programme ........................ 347

APPENDIX 2 : Allocations of tasks .......................................................................................... 351

APPENDIX 3 : Reports and publications .............................................................................. 357

APPENDIX 4 : CEA tasks in alphabetical order .............................................................. 367

APPENDIX 5 : CEA sites ................................................................................................................. 371

- 91 - EFDA Technology / Vessel-In Vessel / Remote Handling

TW0-DTP/1.1 Task Title: CARRIER AND BORE TOOLS FOR 4" BENT PIPES INTRODUCTION This project is an R&D program in remote handling activities for Fusion reactor In Vessel maintenance. The removal/installation of Vacuum Vessel components often requires cutting, welding and inspection of cooling pipes. To allow the replacement of these components while minimising the space requirements, bore tools are preferred to orbital tools for these operations. Following the latest ITER developments, an effort to standardise the pipes inside the cryostat is underway. One of these standards could be 4" pipes (100 mm ID). These pipes will be bent with a bending radius greater than 400 mm and cutting / welding will be required up to 10 meters away from the tool insertion point. The objective of this task is to demonstrate the feasibility to operate with bore tools in 100 mm bend pipes and to study the associated mechanism required. This task includes design activities manufacture and testing of a demonstrator of the basic steps of 100 mm bend pipes maintenance. A modular carrier design was proposed to fit the requirements: - Set up tools from pipe entry point to working zone (10

meters). - Position tools at the correct location. - Generate stress in pipe:

. clamping on pipe,

. compensate internal pipe stress after cutting (100 daN),

. align two faces of pipe before welding (20 mm axial, 10 mm radial 100 daN).

- Provide necessary rescue functions. Process tools required for pipe repair are: - Milling, to cut 80 % of the pipe. - Final cutting with a swaging tool. - Tack welding.

- Butt welding with filler metal. - Non destructive testing to check the quality of the

operation. Feasibility of such a concept was studied during 1998. Manufacturing of a prototype carrier was made during 1999 focusing on the most critical functions needed by the carrier. Clamping modules, an alignment module, a tack welding tool and a swaging tool were designed, manufactured and tested separately. Integrated tests on a swaging operation were made during 2001. The swaging tool was set into the carrier and operated under real conditions in order to make a validation of the final cutting sequence. Another answer to the cutting and welding operations by conventional means was studied. 2003 ACTIVITIES A laser tool was designed and manufactured in order to achieve these two operations with a single tool. Integration of this tool in the BTS carrier started in 2003. In the following picture (see figure 1, starting from the left), we can see: - The winch module which pulls the rigidification cables

between the laser tool and the alignment module. - The alignment module which is needed to release the

stresses in the pipe after cutting and to bring the two pipes to contact before welding.

- The laser tool for cutting and welding the pipe. - The front clamping module for securing the carrier in

the pipe. - The laser connector module. - The annex modules dedicated to storage (camera, wires,

space required by the laser connector in our case…) X2. - The rear clamping module.

Figure 1 : Whole carrier in travelling configuration

Winch Alignment Laser

Front clamping module

Laser connector module

Annex modules

Rear clamping module


The total length of the carrier in the travelling configuration is about 1900 mm. The first test campaign was a validation of all functions on the table. The following operations were made: - Assembly of the tool and function modules.

- Connections and wiring test and verifications.

- Rigidification tests.

- Test of all the functions after rigidification : · clamping, · alignment, · tension with the winch, · laser tool rotation, · laser tool head displacement · CCD camera.

In the second test phase, a pipe mock-up, reproducing conditions close to the real ones was used in order to make a validation of the principle.

Figure 2 : Reference test line used for the validation trials

Recurrent troubleshooting made impossible to perform the complete operating sequence. The reasons are: - The poor reliability of the wiring :

. Lots of cuts or breaks of the wires were experienced

making impossible to have all motors running together at the same time when the carrier was in the pipe.

- For a less part, the rod-pusher used to drive the carrier

and umbilical hasn’t enough power to set in position the carrier with accuracy in :

. The weight of the carrier was too important. . The additional friction due to the presence of an

extra umbilical was too much for the power of the machine.

Solutions to upgrade the carrier were proposed.

CONCLUSIONS Process upgrade studies on the Bore Tools System for 4” bent pipes started the integration of a laser tool in the carrier prototype in 2003. The interfaces and functions were initially clearly defined, and assembly of the tool in the existing carrier were made without any problem. Functional verifications of all equipment were carried on successfully. However, validations tests in real situation were impossible and showed that the limits of the current prototype were reached. The mains technical reasons that were identified are: - the poor reliability of the solutions used for the wiring,

- the complexity of the tool is now too important for this kind of carrier,

- bring some power in front of the tool in a safe and reliable way is a difficult task,

- manage 2 distinct umbilicals affected the performances,

- the use of an industrial laser connector and fibre imposes requirements too strong to the geometry of the carrier without real technical necessity,

- weight of the carrier due to the modifications is now too important.

The initial requirements were probably too ambitious. An essential key of the success in Remote Handling technology is to reduce the difficulty of the task to perform too the minimum. Probably with an increased number of tasks and tools, but in fact, the result is always easier to perform and with a considerably reduced risk of failure. In our case the error was probably to build a tool that can both cut and weld the pipe and to use an existing prototype whose design upgrades were reduced to the minimum for economical reasons. Building three distinct tools to cut, tack-weld and weld the pipe would reduced the complexity of the requirements and could probably be an interesting alternative and ease the tooling maintenance job. REFERENCES [1] European Fusion Technology Programme - Task

Action Sheet T329-4 EXTENSION2 "Bore tools and carrier for 100 mm bend pipes" July 31th, 1999.

[2] European Fusion Technology Programme - Task

TW0-DTP/01 Divertor test platform "Carrier and Bore Tools for bent pipes" November 16th , 1999.


PUBLICATIONS CEA/DPSA/STR - ref. STR/LAM 98/22 rel.0 "Analyse de la faisabilité de l'intervention de maintenance d'ITER par l'intérieur dans des tubes coudés de 4" T329-4". Y. PERROT, August 1998. CEA/DPSA/STR - ref. STR/LAM 98/067 rel.0 "Bore tools and carrier for 100 mm bend pipes T329-4 Intermediate Task Report". Y. PERROT, August 1998. CEA/DPSA/STR - ref. STR/LAM 99/024 rel.0 "Carrier and Bore tools for 4" bend pipes, Etude, réalisation et essais d'une maquette de porteur". Y. PERROT, March 1999. CEA/DPSA/STR - ref. STR/LAM 99/025 rel.0 "Carrier and Bore tools for 4" bend pipes, T329-4, Report on tools manufacturing and commissioning". Y. PERROT, March 1999. CEA/DPSA/STR - ref. STR/LAM 99/095 "Carrier and Bore tools for 4" bend pipes, T329-4, test report on clamping modules. “ Oct. 99. CEA/DPSA/STR - ref. STR/LAM 99/114 rel.0 "Carrier and Bore tools for 4" bend pipes, T329-4, 1999 Intermediate task report". Y. PERROT, O.DAVID December 1999. CEA/DPSA/STR/LAM/00RT.028/Rev.0 Upgrade studies. CEA/DPSA/STR/LAM/00RT.030/Rev.0 Test on the swaging tool and the tack-welding tool. CEA/DPSA/STR/LAM/00RT.049/Issue 0 160mm Bore tooling system. Check up of the status of the system and training of ENEA's operators. CEA/DPSA/STR/LAM/00RT.035/Rev.1 Prospective analysis of bore tooling maintenance work in 2.5" bent pipes. CEA/DPSA/STR/LAM/00RT.089/Rev.0 Performances after upgrade of the Bore Tools for 4" Bent pipes carrier. Report CEA/DTSI/SRSI/LPR/01RT.025 Issue 0 "CWIE Laser module integration tests". Report CEA/DTSI/SRSI/LPR/01RT.027 Issue 0 "M1 of TWO-DTP1.1 Integration of a laser tool in the BTS carrier and management of the umbilical". Report CEA/DTSI/SRSI/LPR/02.RT.006 Swaging with the BTS carrier. Report CEA/DTSI/SRSI/LPR/03.RT.085 Integrated tests of the laser tool and qualification of the process.

SOFT 2000 and Fusion engineering and design 58-59 (2001) "Overview of bore tools systems for Divertor remote maintenance of ITER." J-P Friconneau & al. SOFT 22th Conference. Carrier and Bore tools for 4” bent pipes. O. David & al. TASK LEADER Jean-Pierre FRICONNEAU DRT/LIST/DTSI/SRSI CEA-Fontenay aux Roses Boîte Postale 6 F-92265 Fontenay aux Roses Cedex Tél. : 33 1 46 54 89 66 Fax : 33 1 46 54 75 80 E-mail : [email protected]



TW1-TVA-BTS Task Title: BORE TOOLS SYSTEMS (BTS) INTRODUCTION Fusion reactions like ITER produce high-energy neutron fluxes which cause the structure of the reactor to become radioactive. Man access in the torus will rapidly become impossible. Therefore, any maintenance work must be carried out with help of robotic and Remote Handling (RH) means. Some of the lower parts of the in-vessel structure of the torus form an essential component of the reactor called the divertor. This element is one of the components identified as “requiring scheduled remote maintenance or replacement”. A significant R&D program for the maintenance of the divertor with help of robotic means was launched and huge amount of data is already gathered. Evolutions of the design from ITER 98 to ITER 2001 made some significant changes in the geometry and accessibility of the divertor region, thus rendering some of the remote handling concepts developed during the last framework obsolete. The whole divertor is made of a set of standard elements called cassettes directly connected to a network of stainless steel cooling pipes. Removal of the cassette for refurbishment in hot cells becomes possible when the connection between the cooling pipes and the cassette is broken. Previous studies proposed tool concepts to cut, weld and inspect the weld quality of these cooling pipes from the inside of the pipe. The initial diameter of the pipe standard was 6”, a first evolution reduced the inner diameter to 4” and the last designs are today considering 2.5” ad the new diameter of the cooling pipes. With those new constraints, the first prototype is now useless and perform all the tasks needed for one maintenance operation with a single carrier (clamping, pipe alignment, pipe cutting or welding…) seems a too difficult challenge to keep on trying with that concept. Reflections are now converging on a simplification of the task and on a cooperative work between a carrier sent into the pipe to perform some basic operations (like alignment of the pipe ends before welding) and an orbital tool set in position by the hydraulic slave manipulator used to perform maintenance tasks in the divertor region. Starting from the ITER CATIA model of the divertor region, a first analysis of all the cooling pipes configurations was made in order to identify the critical areas and the zones where access to the pipe is reduced to the minimum.

A representative working area was extracted and simulations with a manipulator model based on a MAESTRO like (Cybernetix hydraulic slave manipulator) architecture were made. The accessibility towards the working area with a virtual cutting or welding orbital tool was then checked and discussed 2003 ACTIVITIES IDENTIFICATION OF THE WORKING AREA A close analysis of the CATIA model in the vicinity of the cooling pipes helped to sort all the pipe arrangements found in the vessel. In fact all pipes arrangements are composed of six pipes feeding three distinct cassettes and five configurations with significant differences were identified. From a maintenance point of view, lots of the tasks in these five configurations are similar. Because we are just starting preliminary studies, only two areas were selected (see figure 1) to test accessibility with the virtual slave manipulator. The simulations took place in the selected pipe configuration. The area was considered to be clear and the arm already inside the torus onboard the CTM. One of the main assumptions taken to build the simulation movies is that the cassette connector was removed by other means before starting the job with the cooling pipes. Access is very tight and some movements are made with a margin close to 10 mm between the manipulator and the wall. Trajectories of the arm can be easily corrected in this model because virtual cameras can be set up everywhere, providing the requested point of view. Real operations with cameras should be more complex. This kind of manipulations is difficult to perform and due to the uncertainties between the models and the real world it seems today unrealistic to run them in full automatic mode. Full téléopération mode also seems impossible because viewing conditions will be poor (good viewing conditions are necessary to run teleoperation tasks safely) and trajectories of the arm will be too complex for that kind of manipulation. Compensation of the poor viewing conditions could probably be made with help of a very accurate real time anti-collision model to minimize the need for the operator to check the position of the manipulator’s segments relative to the in-vessel structures. But this scenario still requires a huge amount of R&D work. Accommodation of complex trajectories will require the ability to run semi-automatic modes.


Figure 1 : View of the two reference areas

Figure 2 : Maestro slave arm accessing the first cooling pipes CONCLUSIONS Accessibility of an orbital tool model to the divertor cassette cooling pipes was checked in a reference case. Access to the pipes becomes possible if: - The remaining parts of the cooling pipes (on the vessel

side) are retracted after each cutting operation, thus clearing the field for the cutting operation of the next cassette. It seems today possible to retract all the pipes by 175 mm without too much problems.

- The cassette connector was removed by other means

before starting the operation. All simulations were made with a tool model that is considered to be very small. During the progress of the manipulator towards the pipe, the clearance between the tool and the walls (or components) is already often critical. Performing the task with a bigger tool will probably be more problematic.


The simulation took place in a model where the design of the real geometry (for both vessel and tooling) is still in evolution. For that reason it is not easy today to have a clear answer to the problem. This study shows that even for the reference case, the difficulty of the problem will be significant. Careful analysis of all the pipe configurations identified at the beginning of the document with an upgraded tool model seems now a real necessity before choosing this option for the reference maintenance scheme. REPORTS AND PUBLICATIONS Report CEA/DTSI/SRSI/LPR/03.RT.100 In-vessel divertor cooling pipes accessibility study for maintenance work. J.P. Martins - O. David.

TASK LEADER Jean-Pierre FRICONNEAU DRT/LIST/DTSI/SRSI CEA-Fontenay aux Roses Boîte Postale 6 F-92265 Fontenay aux Roses Cedex Tél. : 33 1 46 54 89 66 Fax : 33 1 46 54 75 80 E-mail : [email protected]



TW1-TVA-MANIP Task Title : IN VESSEL DEXTEROUS MANIPULATOR Dynamic identification and monitoring capabilities INTRODUCTION Hydraulic manipulators are candidate for fusion reactor maintenance. Such maintenance tasks can be set in constraint and most often blind environments. Performing higher levels of performances to better control the entire system proves to be valuable. In order to monitor the behaviour of the real manipulator, a dynamic simulator of the robot arms is required. We focused this year on the identification of that dynamic model, and analysed the accuracy of this model and its ability to detect failures. 2003 ACTIVITIES We have identified the dynamic model, as seen from the servo-valves pressure sensors. The mechanical model of the robot is :

offsetfrictionGC ττθθθθθθτ ++++Μ= )(),()( &&&&

where : - τ is the vector of the 6 axes torques, which are derived

from pressure measurement ; - the three first terms are due to the articulated bodies :

inertia, centrifuge and Coriolis effects, and gravity torques ;

- frictionτ is the vector of the 6 axes friction torques ;

- offsetτ is the vector of the 6 axes torque offsets, such

that offsetττ − is the real torque.

Torques are directly derived from the pressures difference, measured by the sensors : umD Pτ = The measurements were done on the Maestro with flow control servo-valves, including pressure sensors used for force reflective tele-operation. 35 prescribed trajectories where used for dynamic identification : - axes trajectories with different constant velocities, used

for friction identification ; - axes trajectories with low constant velocity, over the

whole reach and return, used for gravity terms identification ;

- combined sinusoidal trajectories with all axes moving,

with either low or high amplitude and frequency, used for inertial terms identification.

The friction tests of every axis, except axis 4, showed nonlinear viscous friction behaviour, which amount depends on the axis and on its range of velocity. This behaviour has been modelled by the following friction law :

94.1..)(. θθθ &&& cbsignCoulombfriction ++=ττ

where :

Coulombτ is the Coulomb friction torque ; b and c are respectively the linear and nonlinear viscous friction coefficients ;

94.1.θ&c nonlinear component derives from highly probable non laminar effects of flow inside the hydraulic joints.

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offset + constant gravity + friction torque - axis 4 (vertical axis)

experimental datamodel fitted data


The friction behaviour of axis 4 showed Stribeck effect. This axis includes more numerous seals, which may augment dry friction phenomena. The Stribeck effect has been modelled as :

)(..)(.)(.2

θθθθ

&&&&

signebsign StribeckvCoulombstictionCoulombfriction

−

−++= ττττ where stictionτ is the stiction or static friction torque, and

Stribeckv is the Stribeck velocity. All robot parameters have been estimated from the least-square solution of the regressor form of the dynamic equation : Xθθθτ ),,( &&&D= , where X is the vector of

unknown parameters. Stribeckv is the only parameter with nonlinear influence, so it was fixed to the value identified separately, using nonlinear optimization on friction curves of axis 4. The dynamic identification based on the combined trajectories gives inertial parameters, but also gravity and friction parameters, with good agreement with respect to the values obtained from simple axes trajectories.

The values of parameters obtained were also comparable to those estimated from the robot technical plans. The model prediction capability has been tested on an additional combined dynamic trajectory. The residual torques between measurement and prediction were from 2.9 to 8.1 Nm in the mean, and from 12.4 to 52.5 Nm at maximum, depending on the considered axis (different torque capacities). Then the model prediction was evaluated on robot movements obtained using a master arm. A good agreement was obtained, residual torques being from 1.3 to 8.7 Nm in the mean, and from 12.8 to 63.7 Nm at maximum. Situations with unpredicted perturbations were also investigated, where the robot contacted and pushed some objects of its environment. It is shown that external forces, whose influence is not included in the dynamic model, are well detected on the torque residuals. However, the detection of such forces is effective only on moving axes, because with the friction models used, friction torque is undetermined at zero and near-zero velocities. When an axis doesn't move sufficiently, the torque varies between the positive and negative static dry friction values. In such static or quasi-static conditions, only an external perturbation, whose effect on the axis torque is higher than the static dry friction, can be detected.

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CONCLUSIONS The dynamic model of the arm allows monitoring unpredicted behaviours, as collisions or friction with unknown environment. The technique to adopt for real-time monitoring may be direct comparison between predicted and measured torques. Then, the residuals simply have to be filtered with a low pass band filter, in order to eliminate the noise due to numerical derivative. A sophistication of the monitoring could be to identify inline external forces from the residual. The external forces identified could be visualized on a graphic simulator of the planned operation, and compared with the contact forces simulated from the planned contacts. But simulation of contact forces during real tasks cannot, in the state of the art, predict contact forces with a sufficient accuracy. Only important perturbations could be detected during tasks with contact. In case of direct pressure control of the servo-valves, the torque observed would be the input torque command instead of the torque derived from the pressure measurement. Then a filter describing the dynamics of the pressure control should be added to the model. Hence, the results obtained here may be transposed to this case. Moreover, possible failure in the servo-valve would also affect the observed dynamics, when the pressure control dynamics is damaged. Pressure sensors could also be added for monitoring purposes. Then the pressure input would be simply compared to the measured one. In case of flow control servo-valves, the behaviour of the servo-valve could also be monitored from the hydraulic dynamic model linking the valve flow with the actuator velocity. But the identification of the hydraulic parameters would need specific tests with locked actuator. Finally an improvement of the detection could be attained for the static phases (zero and near-zero velocities), using a dynamic model of friction, i.e. a model including state variable that enables to take into account hysteresis, rate dependant friction phenomena and damping effects. Such a model needs still to be identified. It could also be useful for deleting the effect of dry friction in force control.

REPORTS AND PUBLICATIONS DTSI/SRSI/LCI/01RT.088, TW1-TVA/MANIP: Objectives and first modelling analyses. L.Chodorge - C.Bidard. DTSI/SRSI/LPR/02RT.071: Upgrade of the torque model used in the control of hydraulic manipulators. Y. Measson - O. David. DTSI/SRSI/LPR/04RT.013, TW1-TVA/MANIP: Dynamic identification of the Maestro arm and relevance for monitoring, C. Bidard - C. Libersa (to be published). TASK LEADER Jean-Pierre FRICONNEAU DRT/LIST/DTSI/SRSI CEA-Fontenay aux Roses Boîte Postale 6 F-92265 Fontenay aux Roses Cedex Tél. : 33 1 46 54 89 66 Fax : 33 1 46 54 75 80 E-mail : [email protected]



TW1-TVA-RADTOL Task Title: RADIATION TOLERANCE ASSESSMENT OF STANDARD

ELECTRONIC COMPONENTS FOR REMOTE HANDLING INTRODUCTION Validation with the constraints of the expected environment for the future ITER machine on a great number of components and electronic technologies, whether analogical or numerical, lets us consider an incremental approach for the definition and the design of complex electronic functions. The work undertaken in 2002 made it possible to develop and carry out an optoelectronic link in collaboration with the SCK team. This work allows to transferto the control room an analogical signal transcribed in the phase modulation of a pulse. In 2003, it was a question, initially, of completing the study of the AD534 component (from Analog Devices) necessary to the treatment of the analogical signals resulting from the resolvers usually used in nuclear robotics. Then, the work concerned the definition and the design of the serialisation function of digitized data. The models, experiments and results are described in this article. 2003 ACTIVITIES A functional block (see figure 1) summarizes the developments conducted during this year.

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Figure 1 : Synoptic diagram of electronic functions implemented in 2003

LINE DRIVERS Line drivers fully connected to serialisers need differential protocols. The usual drivers are probably obsolescent today. Recent LVDS protocol, which could be assimilated to an adaptation of the well-known RS-485 protocol to low level signals, were evaluated at the end of 2002.

Last results given on [1] confirmed a significant interest for either dose or temperature. AD534 IC Resolvers need multiplicative functions to generate data related to the measured angle. The analog values given by a resolver, tA ωφ coscos and tA ωφ cossin , are multiplied by tB ωcos in order to produce a signal proportional to

φsin or φcos . The remainder of the operation, a signal at tω2 frequency is eliminated by an adapted filter.

Experiments under radiations done on AD534 (from Analog Devices)[1] on a mock-up realizing a multiplicative function give significant results for low dose levels, such as a few tenth of kGy. Studies of the behaviour at higher dose have shown a loss of functionality, with a very rapid recovery when warmed at about 150°C after radiation. This specific availability has been taken into account to evaluate the combined effects of dose and temperature. A new experiment has been scheduled with the same mock-up as previously.

Figure 2 : Mock-up used for temperature and radiation experiment

The results given on figure 3 mainly show a continuous degradation of both AD534 components, leading to a probable loss of functionality. However, no fatal destruction seemed to happen. Drifts were observed very shortly after the temperature reached the value of 82°C (chronogram number 2) with the loss of the multiplicative signals only a few hours later (compared to a few tens of hours at lower temperature). It is thought that high temperature accelerated that loss of functionality. However, the expected recvery was not effective. Predominance of radiation has, at least, masked the uncertain benefit of temperature.

AD534


Figure 3 : Chronograms taken during the experiment One will also notice on the right side chronogram that when irradiation and heating were stopped, a partial recovery could be seen. The resumption of the initial test conditions led to a new deterioration of the multipliers signals, maintained until the end of the campaign. After a few months of rest period, at laboratory conditions and without any bias, all the irradiated components (from non heated and heated experiments) were reused without any defaults. COUNTER FUNCTION The availability of this function is essential for the realization of many complex electronic functions (AD conversion, pulses count, …). Results with integrated counters in LS technology were not satisfactory, and led to a new design of the counting function starting with the simplest low voltage CMOS components. First experiments done with older CMOS technology [2] show that they remained functional up to 10 MGy although a significant increase of current and a need for a more important supply voltage were observed. The study suggested here uses a concept of counter based on D type flip-flops, the simplest components able to generate a counting function. Figure 4 details this counting function. Components AUC79 (upper line) provide the Q exit of the flip-flop. It is thus necessary to add a AUC04 invertor to recreate the Q~ output necessary to the counting. Component AUC80 (bottom line) directly delivers the Q~ output. The initial clock corresponds to the number of pulses to count. The data obtained on the upper part of the schema correspond to a direct counting whereas those obtained on the lower part correspond to a countdown. In any of these components, the reset function is implemented, which forces to realise a non-stop counter with a little computing in the control room. The mock-up (see figure 5) showed a correct operation during laboratory tests.

LATCH OR FLIP FLOP FUNCTION This well-known function (not shown on figure 1) allows to memorize a state before conveying it on the back-plane buses whether parallel or series (in this case, frames are constituted then data are serialized). This function can be completely fulfilled with AUC79 type components for which the various D entries receive the data to be memorized and where the clock is common to ensure the memorizing synchronization.

Figure 4 : Electronic schema of the counter function Nevertheless, a few of these integrated components allow to have multiple entries and memorizing synchronized on an edge or a state clock signal. The goal of this function is to ensure this validation.

Figure 5 : Mock-up of counting function We retained the 373 type components family for memorizing on state and the 374 type for memorizing on edge. These components are common to several CMOS technologies and have the “3-state design”, very useful when the card must be isolated from the buses. As the design shows it on figure 6, 8-latches components ACMOS AC373 and AC374 and 16-latches components of more recent CMOS technology AVC16373 and AVC16374 were used. The bits positioning configurations were chosen to cover the various memorizing states (permanent to 0, permanent to 1 and dynamic). The sensitivity to the high or low impedance states is also taken into account when defining the test sequences.


Figure 6 : Mock-up of the latches and serialiser functions

SERIALIZING FUNCTION The two preceding functions simulate the usual data resulting from sensors embedded on remote robotics. Thus the latches will memorize the states of proximity sensors. Counting will quantify the duration of phase outlets of resolvers or US sensors. The simultaneous provision of the binary states representing these data requires a high number of cables, not easily reconcilable with the requirements of remote engines in constrained environment. It is then necessary to carry out a serialisation of these states as quick as possible, and to transmit the information on a single cable, the management of the delay to the availability of the data being to define within the control loop of sensors/actuators. The obsolescence of the bipolar LS technology and the lack of the equivalent shift registers in CMOS technology led us to redefine this function using the existing components which functionalities enable us to ensure the serialisation and de-serialisation of frames. We chose the data multiplexer 74AVC16369. With its 12-bits double input register and its 12-bits output register, one can reconstruct with the same component the memorizing, serialisation and deserialisation functions for the transferred data . One can thus constitute a 12 bits frame. The possible chaining between these components enables to extend to the desired length the frame one wishes to emit. EXPERIMENTAL RESULTS This test-board thus comprises three different CMOS technologies requiring three different supply voltages. Unfortunately, only two supply sources were established during the manufacturing of the mock-up, a later modification being considered too risky taking into account the smoothness of the connections between components. Logics AVC and ACMOS were gathered on the same source with 3,6 V. ACMOS technology, while remaining functional, is thus underfed compared to its nominal voltage of 5 V. AVC technology is a little bit overfed while remaining in its nominal range of operation.

The test card was irradiated within SCK facilities as shown on figure 7 on April 2003 with a dose rate close to 20 kGy/h and an average temperature near 60°C. The consumption, which raised at the beginning of the irradiation experiment, is 130 mA for the 3,6 V and 30 mA for the 2,4 V. These values remain correct taking into account the context (cable lengths, multiple interconnections…), and the imposed overfeedings.

Figure 7 : Mock-ups of logic functions when bottled before radiation

Some weldings were destroyed at the time of the encapsulation because of the great rigidity of the polyimide cables. After modification the experiment could start. The currents measured just after the end of the irradiations (< 10 mA for the tension of 3,6 V and 130 mA for 2,4 V) very clearly show a degradation induced by the irradiations. The study of the mock-up does not show any visible break in the cables or welding. Nevertheless, the intermediate supports for the counting module and some connections suffered from this accelerated ageing. On the other hand, the card manufactured on a polyimide support perfectly behaved and did not show any trace of deterioration : this will have to be the rule for the future prototype of multiplexer. In any case, the cards necessary to the multiplexing prototype should not comprise any more additional supports, the components all being welded onto a single printed circuit.

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Figure 8 : Logic “1” state during irradiation of ACMOS components


The study of the measures of the latches and flip-flop components shows that the drift of the operation supply of the recent CMOS technology exceeded the supply voltage to which the components were subject during the irradiations. One will note that the lack of acquisition occurred between 1500 and 3000 kGy following an electric breakdown having caused during a few minutes the stop of the supply, the restarting of acquisitions occurring approximately sixty hours later. The rather usual behaviour on the evolution of the minimal operation tension, which was observed again with the CMOS components, affected all components of the mock-up. Until the unexpected interruption of the acquisition between 1500 kGy and 3000 kGy, the behaviour of ACMOS components (see figure 8) remained correct. An instability zone easily visible between 3000 kGy and 8000 kGy which should be seen as the rising of the minimum voltage supply, is followed of a permanent wrong state. The behaviour of more recent technologies is much more unstable (see figure 9). The permanent wrong state appears near 5 MGy. Here also, it should be seen as aconsequence of the rising of the minimal voltage supply which reaches earlier nominal voltage.

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Figure 9 : Logic “1 state during irradiation of AVCMOS components

The results of the frame signal are very difficult to be interpreted because the effect of radiations on the supplies used for the different technologies most probably led to the impossibility to establish correct logic levels. POST-IRRADIATION STUDY OF IRRADIATED COMPONENTS The post-irradiation study of the mock-up was made in our laboratory on May 2003 on the same test bench as the one used during the irradiations. With the supply, the behaviour of the card was identical to that observed at the end of the irradiation. The supply voltage was then increased to evaluate the degree of degradation of the card.

Normal operation, independent of the ACMOS and AVCMOS technologies, was found on the bits activated by the test software for a voltage close to 4 V, approximately 0,5 V above the supply used during irradiation. A manual checking of the other entries of each component was also made. No defect was found. After a few operating hours, a test was carried out to evaluate the post-irradiation effects. No recovery seems to have occurred since degradations were again found near 3,5 V. It also appears that the components became sensitive to the "latch-ups", i.e. presenting an over-consumption. This phenomenon disappears when one disconnects and then reconnects the components or the card supply. It is significant that the components remain functional. However, they present a degradation introduced by the dose effect that “fix” the minimum voltage supply significantly higher than nominal. The phenomenon has been confirmed all along the six months recovery period. The supply voltage of the counting card was also increased around 3,26 V in order to find a functional counting state checked with the oscilloscope (see figure 10). One thus observed the evolution of the counting (or the countdown) of a 2 bits step on the signals coming from the two serialisers of the card on request of an external clock. The two signals are perfectly identical, which proves the return of all the card’s functionalities. It also appears that the minimum voltage has been fixed near 3,3 V.

Figure 10 : Framing during post-irradiation tests CONCLUSION In order to complete the works done within the ITER T252 tasks, complex electronic components and functions have been evaluated to different irradiations conditions. Most of these components remained functional after the end of the irradiation. A heated recover period at 150°C has mainly allowed to retrieve nominal characteristics.


Concerning the multiplier function done by the AD534 components, it has been confirmed that the drifts due to radiation effects did not disappear under the combined radiation and temperature environments. The influence of high recovery temperature (up to 220°C) was also confirmed. A further study of this component, using input adjustments to control output drifts, should be done as soon as possible to validate a proper use. Concerning logic components, the utility of CMOS technologies was demonstrated even if the supply voltage increase led to some failures when this voltage appears too low to allow correct CMOS conduction. In order to take into account the failures arising when different CMOS technologies are integrated to design a complex function, the use of open-drains components is required to avoid any voltage discrepancy. In an other terms, the partial re-design of the function will be encouraged to limit technologies interference. REPORTS AND PUBLICATIONS [1] Annual Report of the Association EURATOM/CEA

2002, pp 329-334. [2] Annual Report of the Association EURATOM/CEA

2001, pp 119-123.

TASK LEADER Alain GIRAUD DRT/LIST/DTSI/SARC/LCSD CEA-Saclay F-91191 Gif-sur-Yvette Cedex Tél. : 33 1 69 08 64 30 Fax : 33 1 69 08 20 82 E-mail : [email protected]



TW2-TVR-IVP TW3-TVR-IVV

Task Title: PROTOTYPICAL MANIPULATOR FOR ACCESS THROUGH IVVS

PENETRATIONS (IVP) AND IVVS DEPLOYER INTRODUCTION This project takes place in the Remote Handling (RH) activities for the next step of the fusion reactor ITER. The aim of the R&D program is to demonstrate the feasibility of close inspection of the Divertor cassettes and the Vacuum Vessel first wall of ITER. We assumed that a long reach and limited payload carrier penetrates the first wall using the 6 penetrations evenly distributed around the machine and foreseen for the In-Vessel Viewing System (IVVS). The need to access closer than the IVVS to the Vacuum Vessel first wall and the Divertor cassettes had been identified. This is required when considering inspection with other processes as camera or leak detection. The objective of this task is to demonstrate the feasibility of such operations along the vacuum vessel wall with access from existing IVVS penetrations. This carrier will be called In Vessel Penetrator (IVP). This task began in 2000 includes design activities, manufacture and testing of a demonstrator of an articulated manipulator. In parallel of this design, technologies able to be used under vacuum and temperature were selected, tested and validated. The design of a completely integrated vacuum prototype to be tested under ITER relevant conditions was performed during 2002 and ended in 2003. There is also an urgent need to develop the design and necessary technology to provide a means of deploying the IVVS probe from its storage position into the plasma chamber under vacuum conditions, vessel operating temperature (approx. 120°C) and the presence of the toroidal magnetic field. The analysis of the requirements of this IVVS deployer was performed based on the geometric performances of the IVVS probe. An analysis of the feasibility of the design of an articulated inspection arm working under vacuum, temperature and magnetic field conditions was also performed to select usable technologies.

2003 ACTIVITIES DESIGN OF A VACUUM AND TEMPERATURE MODULE DEMONSTRATOR AND MANUFACTURE To satisfy ITER operational condition (T° & Vacuum), IVP original design had been upgraded with all selected suitable technologies. This Prototype is now called AIA (Articulated Inspection Arm). The main design options that were chosen are : - Use of metallic alloys for the structure materials such as

titanium.

- Some other non organic materials could also be used like Vespel.

- Use of welding processes for assembly of the structure parts.

- Use of temperature hardened DC motors for electric actuators.

- Gearbox will use standard reducers. Roller screw and gearbox should be lubricated and embedded in a tight sealed box with the motors.

- Use of jack like actuator when possible.

- Use of needle bearings with dry lubricant.

- Use of HCMOS military electronics components with a dedicated robot network. Electronics will be embedded in tight boxes with tight feed through or connectors.

First scope of the demonstrator is the validation of the technologies on a single module prototype. The prototype module is focused on the base module (the most heavily loaded of an robot) with 2 degrees of freedom and is now under manufacture. After proof of performances of the most loaded module, final design of the AIA could occur. To be tested under realistic operating conditions of vacuum and temperature, the AIA demonstrator will be manufactured with respect of CEA Tore Supra (TS) constraints. In particular, design will be compatible with TS dimensions, then the elevation axis will have + - 45° range and the complete robot total length will be 7.4 meter.


Figure 1 : AIA assembly design

FEASIBILITY STUDY OF AN ARTICULATED INSPECTION ARM WORKING IN VACUUM, TEMPERATURE AND MAGNETIC FIELD One of the tasks to perform by remote handling concerns the inspection of the inner walls of the vacuum chamber. Each constraint afford by the robot represents less time in the maintenance process because each task (the pumping to reach vacuum, and the conditioning by heating) take much time. So, the Articulated Inspection Arm (also called IVP) design proposes today to allow the work under vacuum and temperature conditions. In addition, there is a constrain which imposes to avoid the shutdown of the toroidal magnetic field as possible and particularly between two plasma pulses. This has some consequences on the design of the inspection systems. The analysis of the consequences of the magnetic field on the current design of the AIA was performed and proposed some solution to build an arm able to afford all the constraints in the same time. This analysis will also be needed for the design of the IVVS deployer. The main results of this analysis are the followings : - Contribution of magnetic field on load on structure will

increase around 20 % of additional forces. Design of AIA seems feasible with performance limitations.

- No electronics components are available. Design with optics components could be possible for the sensors and the data transfer system.

- Actuation is a key issue and we can expect promising

results by using remotely controlled water hydraulics. This topic need a new significant R&D work to show proof of principle technologies.

These results show that the main part of the components to make an AIA working under magnetic field are missing today. Pending issues to design the IVVS deployer will require significant R&D programs to demonstrate the feasibility of Remote Handling under magnetic field. IVVS DEPLOYER : ANALYSIS OF THE REQUIRE-MENTS Task TW0-DTP/01 resulted in the design and manufacture of a proof-of-principle model of a viewing probe and associated control system with the capabilities to meet the in-vessel viewing and metrology requirements of ITER. Continued development through task TW1-TVA-IVP will result in the thorough testing of this system. In parallel with these activities there is an urgent need to develop the design and necessary technology to provide a means of deploying this probe from its storage position (in a divertor port plug) into the plasma chamber under vacuum conditions, vessel operating temperature (approx. 120°C) and the presence of the toroidal magnetic field.


We analysed the requirements of the new configuration of storage of the IVV probe and study a system able to deploy the probe from a Divertor plug to the measurement point in the VV. The first step in this process was a kinematics CAD analysis to determine the deployer geometry. Computations will also provide rules for the design of the deployment system based on the required number of axis of the deployer and the payload of the IVV probe. The work performed during this study has defined the IVVS deployer requirements and has also shown the need of a multi axis device to be able to acquire full vessel area images with the IVVS, even if the probe is equipped with an auto focus. The next step of the study would be the definition of the deployer architecture. This work could be done in 3 steps : - Improvement of the program to obtain a shorter

computation time and a lighter 3D output model. - Computations on IVVS probe positions to determine

improved positions where the deployer should place the probe.

- Study of the deployer to define the number of degrees

of freedom. The software program improvement could also be useful for other future intervention tools in ITER vessel for correcting position of measurement tools. Whatever will be these tools, it will be necessary to know what is the incidence angle from the tool to the vessel surface to analyse the quality of the measured information or to compensate the measure. CONCLUSIONS The IVP feasibility study performed in 2001 - 2002 was continued with the design of a prototype module. The needed vacuum and temperature technologies are validated to design an AIA able to cop with ITER environment conditions and had been integrated in the design of the prototype module. Manufacture of this prototype module will be achieved in the beginning of 2004 and a test campaign will start under ITER relevant conditions. The work performed during the second part of the work has defined the IVVS deployer requirements and has also shown the need of a multi axis device to be able to acquire full vessel area images with the IVVS. The design of this system will need a significant effort to the technologies able to cop with the ITER requirement of operation under magnetic field.

REFERENCES European Fusion Technology Programme - Task TW0-DTP/01.2 Divertor test platform "Prototypical manipulator for access thought IVVS penetrations" November 16th , 1999.

European Fusion Technology Programme - Task TW0-DTP/01.4 Divertor test platform "Review feasibility of limited maintenance inspection operation under vacuum" June 10th , 2000.

European Fusion Technology Programme - Task TW1-TVA/IVP April 12th , 2001.

European Fusion Technology Programme - Task TW2-TVA/IVP October 10th , 2001.

European Fusion Technology Programme - Task TW3-TVR/IVV July 1st , 2002. PUBLICATIONS CEA/DTSI/SRSI/LPR/03RT.004/Issue.0 In Vessel Penetrator (IVP) Vacuum and temperature electronics report.

CEA/DTSI/SRSI/LPR/03RT.041/Issue.0 In Vessel Penetrator (IVP) Vacuum and temperature design report.

CEA/DTSI/SRSI/LPR/03RT.095/Issue.0 In Vessel Penetrator (IVP) Control and model of a flexible manipulator.

CEA/DTSI/SRSI/LPR/03RT.081/Issue.0 IVVS deployer, Analysis of the requirements.

CEA/DTSI/SRSI/LPR/03RT.104/Issue.0 IVVS Deployer, Feasibility analysis of an articulated inspection arm working in vacuum temperature and magnetic field conditions.

CEA/DTSI/SRSI/LPR/03RT.098/Issue.0 Articulated Inspection Arm (AIA), IVP project presentation and road map to AIA. TASK LEADER Jean-Pierre FRICONNEAU DRT/LIST/DTSI/SRSI CEA-Fontenay aux Roses Boîte Postale 6 F-92265 Fontenay aux Roses Cedex Tél. : 33 1 46 54 89 66 Fax : 33 1 46 54 75 80 E-mail : [email protected]



TW3-TVR-RADTOL Task Title: RADIATION TOLERANCE ASSESSMENT OF STANDARD

ELECTRONIC COMPONENTS FOR REMOTE HANDLING INTRODUCTION In order to prototype a full data acquisition module from sensor data to control room in a two years scheduled program, the aim of this year’s activity is to present the progress on the design of data acquisition for sensors such as resolvers and Linear Variable Differential Transformer (LVDT), mainly requested by remote handling engines designers. Depending on the resolver’s principle, two different digitalizations of the output resolver signals are described : one is based on multiplicative function, the other uses time measures. Following the same investigation, two principles of LVDT measurements are proposed. Design of electronic modules mock-ups, based on electronic components previously validated under Fusion constraints, are presented as well as results of partial irradiation tests. Finally, to show the different uses of a resolver, one of the electronic mock-ups was validated with the design of a compressed-air motor system. 2003 ACTIVITIES A functional block summarizes the developments conducted during this year. Three well-known sensors in the field of remote handling have been selected in order to design the electronic functions which could be included in a “black box” to digitalize and frame analog data. As shown on figure 1, two resolvers are used, coding the phase angle as sin(φ) and cos(φ) for the first one, and sin (ωt + φ) for the other one. A LVDT has been added for the measurement of a security distance.

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Figure 1 : Synoptic diagram of the electronic functions implemented in 2003

BRX RESOLVER The first resolver, currently named BRX resolver, uses one primary coil with an ( )tA ωsin as input and two secondary coils with ( )tA ωφ sinsin and ( )tA ωφ sincos outputs. The behaviour of the most common multiplier component, an AD534 from Analog Devices [1] had previously shown a significant drift of the outputs under the expected ITER environments (150°C and about 10 MGy of total dose) [2] [3] [4]. However, the full functionality recovery after irradiation, heated or not, has allowed to deeply investigate such a critical component. For this new experiment, two components have been implemented on the test-board (see figure 2), the first one to simulate the resolver, i.e. to provide a ( )tωφ sinsin signal as output, the other to provide a tωφ 2sinsin signal, which is equivalent to ( )( ) φω sin2)2cos1 ∗− t . An additional low-pass filter is necessary to extract the useful φsin signal. An extra input Z2, never used on the basic multiplier connection, is supplied in order to create a compensation to limit the drift.

Figure 2 : Functional block of AD534 experiment The mock-up (see figure 3) was first irradiated at a low dose rate. After a few irradiation weeks , the drift observed on the filtered signal (see figure 4) is not very important and remains easily compensated by the Z2 voltage.

Figure 3 : Mock-up of BRX resolver


The second irradiation test, at higher dose rate (near ITER constraints) appears very decisive for the component choice.

Figure 4 : Recorded signals of BRX mock-up during low dose rate tests

The regular controls done during the three test weeks did not seem to be effective enough to stop the drift (see figure 5), even if, each time, the compensation effectively reduced the fluctuation.

Figure 5 : Recorded signals of BRX mock-up during high dose rate tests

RESOLVER BRT The second resolver, called BRT resolver, uses an other method to provide the phase angle. Two primary coils are supplied by ( )tA ωsin and ( )tA ωcos at input and one secondary coil delivers a ( )φω −+ /sin tA at output. There is no need of a multiplier or A/D converter. The extraction of the ϕ angle only requires the design of some simple analog and digital functions: - An embedded cosine function. - A zero level detection on input and output sine

functions. - A pulse signal corresponding to the duration between

the detections of the two zero level transition. - A burst function able to convert the duration into a burst

of sub-pulses, their number depending of the precision requested for the phase angle.

- A counter able to convert these bursts of pulses into a

binary value and a digital serialiser function able to frame and send to line drivers the binary value of the angle, the angle value being computed at control room. These two last sub-functions were validated in 2002 and earlier [4].

All the components selected for the functions summarized on figure 6 were previously identified for their radiation and temperature tolerance.

Figure 6 : Functional blocks of BRT resolver experiment After a unity gain OPA stage necessary to avoid any losses on the BRT signal dynamic, the ( )tωsin and ( )φω −+ /sin t signals are compared to 0V by an second OPA used as a comparator. The delivered square signals offer more precision than a sinusoidal signal. Rectifying diodes limit the signals to positive values. These functions were designed with OAP27 BB and OPA277B operational amplifiers [7]. The signals are then adapted to logic AUC technology [5] input level and isolated from logic stages. These components are supplied at 1.8 V. A logic JK flip-flop made with elementary AUC components, impose a priority between its two entries and works as a phase comparator. This property is very useful to choose a signal as phase origin. A 2 MHz oscillator, using quartz and AUC1G14 inverter, samples the pulse delivered by the flip-flop.

Figure 7 : Recorded signals at different digitalization steps

The main signals of a BRT resolver mounted on a testbed (see figure 8) are shown on figure 7. When working, the pneumatic motor produces a rotation angle between 0 to 2π. Whatever the direction of the movement, the flip-flop pulse is modulated between a full “0” level and a full “1” level.

Output of 2nd AD534

Output of 1st AD534

Filter’s output

BRT input and output signals

Flip-Flop

Sampled signal


Figure 8 : Experimental test-bed used to validate the BRT mock-up

No significant drifts were observed on the main signals of the mock-up after a 5 MGy total dose. On figure 9, the pulse signal is measuring a very narrow angle while a few 10 samples digitalize it.

Figure 9 : Recorded signals after at least 5 MGy Counting the samples is made by a shift register designed with simple D-flip-flops [4]. Up to now, it has not been implemented on this mock-up. LVDT SENSOR A LVDT (Linear Variable Differential Transformer) is an incremental position sensor using the principle of the inductive coupling based on a transformer. This means that it has a primary winding and two secondary windings, as well as a mobile core. By cabling the secondaries in phase (as possible with the LVDT we bought), when the core is in central position there is an equal induced tension. The difference voltage Vs is then null. During normal operation, when the core moves toward one or the other coil, the difference between the secondaries reflects the image of the displacement. Then Vs is not null any more. The digitalization of the LVDT analog sine signals requires the design of some analog and digital functions.

- A differential amplifier to collect the displacement’s intensity.

- A rectifier stage to deliver a “RMS”-like output. An

RMS integrated circuit AD736 has been optionally added to evaluate its radiation tolerance.

- A direction detector based on a zero threshold detection. As for the resolver’s functions, these functions were designed with OAP27 BB and OPA277B operational amplifiers. After a total dose of 3,5 MGy , using a high dose rate configuration, the mock-up remained operational. The dynamic of LVDT displacements doesn’t seems to be strongly affected by radiations while an hysteresis appeared on the direction signal. ANALOG TO DIGITAL CONVERTER As shown on figure 1, the availability of an analog to digital converter is a critical point. Most of the developments realized for civilian nuclear applications refer to the common tracking loop method associated with a Digital to Analogue Converter (DAC) component like DAC512 and DAC08. The earlier investigations done on these components under ITER constraint [6][7] have driven us to select DAC08 for a first step of full data link. The lack of logic complex counter functions, but also the sensitivity to bias conditions of DAC08 and a final feedback loop estimated at a few hundred of ms by the final users, allow to design a simpler conversion module shown on figure 10. The conversion design requires some more functions. - A counter to deliver non-stop digital 8 bits values to the

DAC08. - A register to latch the digital value corresponding to the

analog converted value. - A comparator, which gives signals necessary to the

previous latches when the DAC converted value is equal to the analog value to convert.

The mock-up, as for the other functions, mainly uses previously validated components and logic components from TI AUC technology for counters, latches and drives functions.

Figure 10 : Functional block of the AD conversion


The chronograms on figure 11 show the different signals observed when the analog voltage reaches the corresponding converted voltage given by DAC08.

Figure 11 : Chronograms of non stop counting and latch edges

After a total dose of at least 2 MGy , all the signals kept the same aspect. No significant drift has been observed on conversion dynamic. Unfortunately, radiation affected the reliability of the mock-up, as some Teflon coated wires began to be reduced to dust and printed card to be broken (see figure 12). Short-cuts have disturbed the last hours of irradiation and limited quality of the recorded measures. However, the principle of such a simple conversion is now validated.

Figure 12 : Mock of the ADC function (before and after irradiation)

CONCLUSION The use of BRX resolvers needs a very sensitive IC, AD534 which presents drifts on output signals. A compensation signal has shown some efficiency at low dose rate and, for such environments, could allow to retain such sensors. Using instead BRT resolvers implies the design of simpler components. The digitalization could be easily obtained under high dose rate conditions. The digitalization of an LVDT sensor should not introduce difficulties to assume a good reliability under high dose rate environments. In any case, some works should be done on the mock-up to provide an accuracy closer to the requests of the final users. Epoxy printed cards and Teflon coated wires must be forbidden for any applications above one MGy. REFERENCES [1] Data sheet of AD534 on website of Analog Devices. REPORTS AND PUBLICATIONS [2] Fusion Technology : Annual Report of the

Association EURATOM/CEA 2002 pp 91-95. [3] A.Giraud, TW1-TVA-RADTOL, intermediate report

of June 2002. [4] A. Giraud, TW1-TVA-RADTOL, final report of

December 2002. [5] Fusion Technology : Annual Report of the

Association EURATOM/CEA 2002 pp 329-333. [6] Fusion Technology : Annual Report of the

Association EURATOM/CEA 2000 pp 85-90. [7] A. Giraud T252 final Report, DTSI/SLA/02-299. TASK LEADER Alain GIRAUD DRT/LIST/DTSI/SARC/LCSD CEA-Saclay F-91191 Gif-sur-Yvette Cedex Tél. : 33 1 69 08 64 30 Fax : 33 1 69 08 20 82 E-mail : [email protected]

- 289 -

UNDERLYING TECHNOLOGY PROGRAMME

EFDA Technology

1- Vessel-In Vessel - Plasma Facing - Assembly and Maintenance 2 - Tritium Breeding

and Materials - Breeding blankets - Materials development

3 - Safety & Environment

- 290 -

- 303 - Underlying Technology / Vessel-In Vessel / Remote Handling

UT-VIV/AM-Actuators Task Title: REMOTE HANDLING TECHNIQUES Advanced technologies for high performances actuators INTRODUCTION This task follows UT-RH3 Actuators. Maintenance of fusion reactors induces high requirement on robotic device. In addition of the hazardous environment condition; maintenance requires high performances for robotic devices. In fact, high load are required to be handled, and narrow space is available for the motion. Conventional design of robotic device reach its limit in such condition. In order to build adequate handling or inspection RH device, R&D activity is required on this field. State of the art actuator used to drive robotics devices need improvement in term of load capacity versus size of actuator. The task is now finished. PREVIOUS WORK Actuators based on the thermal expansion of wax have shown exceptionally high ratio load capacity versus size and weight. Their main drawback is a long response time but it is not lethal for maintenance tasks. So we decided to make use of them to build a bore tool device suited for 2.5" pipe (Ø 63.5 mm) where conventional actuator clearly do not fit the requirements. In a first design, the tiny insulating pieces made of ceramic have proved to be too brittle. But insulating-thermosetting trade-off has to be done to choose this material. After acceptable results from thermosetting and indentation hardness tests on phenolic material (celoron), we decided to use it to realize the insulation pieces of the future mock-up. 2003 ACTIVITIES The previous design [5] still show some drawbacks:

- insufficiency of the electric insulation, - friction in the synchronization device, - bending torque on the dogs causing jam torque. The new design was carried on in 2003 intends to overcome those drawbacks. The insulation is improved through:

- an extended use of insulation material, - the use of normalised connector pin.

The synchronisation device benefits of the improved shape (Exact Archimede’s Spiral) of the cam, that eliminates disturbing forces causing jam. No more bending torque on the clamping dogs occurs thanks to the use of two symmetrical disk located on each side of the dogs.

Figure 1 : Outside view of the new module

Figure 2 : Inside view of the new module

Figure 3 : Cut view of the new module Red : normalized connector pins. Brown : phenoplast (Celoron). Pink : Vespel or Delrin. Blue : Steel or Aluminium.


Figure 4 : Archimede's spiral trajectory

Figure 5 : New synchronisation disk

PUBLICATIONS [1] Report DPSA/STR/LAM/00RT.050/Issue 0 - Over-

view of the possible applicable technologies UT-RH3 - A. Riwan.

[2] Report DPSA/STR/LAM/00RT.097/Issue 0 - Pre

design of possible actuator, evaluation of candidate technology UT-RH3 - A. Riwan.

[3] Report DTSI/SRSI/LPR/01RT.029/Rev.0 - UT-

VIV/AM: Detailed design of the prototype actuator - A. Riwan - August 10, 2001.

[4] Report DTSI/SRSI/LPR/02RT.001/REV.0 - UT-

VIV/AM: Test on a clamping module made of thermal actuators - D. Arhur - A. Riwan. January 14, 2002.


VIV/AM: New design and test planning of a clamping module - D. Arhur - January 20, 2003.


VIV/AM: Latest design of the clamping module - A. Riwan, C. Petit - June 20, 2003.



UT-VIV/AM-Hydro Task Title: REMOTE HANDLING TECHNIQUES Technologies and control for hydraulic manipulator INTRODUCTION Hydraulic manipulators are candidate for fusion reactor maintenance. Their main advantages are their large payload with respect to volume and mass, their reliability and their robustness. However, due to their force control limitations, they are disqualified for precise manipulation and are dangerous for the environment and themselves in case of unexpected collision. CEA, in collaboration with CYBERNETIX and IFREMER has developed the advanced hydraulic robot MAESTRO. Using “pressure” control servo-valve instead of the standard “flow” control servo-valve makes a real simplification of the control loop. The French company IN-LHC, designed and manufactured a prototype of servo-valve that fits the performances and space constraints of the Maestro arm. Integration of this new product in the Maestro arm was made and qualification test are in progress. Upgrade studies on this activity are focusing on the use of water instead of oil as a fluid medium. Even if the new generation of Maestro slave arms (see figure 1) successfully ran through a 1000 hours endurance test with success (see the concerned section), ITER’s requirements can’t stand any oil drop in the vessel due to a leak in the master arm.

Figure 1 : New generation Maestro master arm

Servo-valves are on the critical path for the change of fluid medium. Flow control servo-valves using water are already available on the market but their reliability in long term tests still need to be proven. In cooperation with the manufacturer In-LHC, CEA tries to develop a prototype of pressure control servo-valve using water that fits the requirements of the Maestro slave arm. 2003 ACTIVITIES INTEGRATION OF THE PRESSURE CONTROL SERVO-VALVE PROTOTYPES Integration tests of a Maestro slave arm fully equipped with pressure control servo-valves are just starting. A maintenance program on the Maestro used for these test was made in order to perform these tests with a reliable device. The servo-valves are now in the arm (see figure 2) and the tests will start soon.

Figure 2 : Pressure control servo-valves in the forearm of the Maestro

RELIABILITY TESTS WITH THE NEW GENERA-TION MAESTRO A new generation of Maestro arm has been designed. The aim was to design a hydraulic arm taking into account the experimental feedback gained during tests in real conditions of dismantling operations: metal cutting, nibbling, bolting… Re-design of the arm was started according to specifications issued from theses tests with the objective to build an arm easy to maintain and reliable. All the components and equipment were chosen or tested to provide a rad-hardened tool (max 10 Gy/hr or 104 Gy cumulated dose). Characteristics (speed, payload, strokes) are similar to those of the original version. Reliability of this new generation Master arm was proven during a 1000 hours test.


The effective load applied on the arm during this campaign was approximately divided as follow: - 355 hours without payload, - 333 hours with a 25 daN payload, - 317 hours with a 50 daN payload. Two different paths were followed during the tests: - The first one where all axis were moved from one stop

to the other starting from an initial position. Run at 80 % of maximal speed without payload and with 25 daN at the end of the arm and at 25 % of the maximal speed with a 50 daN payload.

- The second one was defined like a standard remote

handling task (pipe cutting for example). This task was run at a speed close to the one used in standard remote handling tasks.

The accuracy of the control schemes provides good performances in position tracking tests even with a 50 daN payload when the speed of the arm stays in the range used in teleoperation tasks (see figure 3).

0 10 20 30 40 50 60 70 80 90 100-0.015

-0.01

-0.005

0

0.005

0.01Position error, axis 3

Pos

ition

[rad

]

Time[s]

0 10 20 30 40 50 60 70 80 90 100-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04Position error, axis 5

Pos

ition

[rad

]

Time[s]

Figure 3 : Position error of the axis 3 and 5 with a 50 daN payload and after the endurance test

No major breakdowns were noticed during this test. But default of some pressure sensors raised the question of reliability of the classical system “flow control” servo valve + pressure sensor used to control the joint. This is one more argument to use the already tested pressure control servo-valve set. DESIGN AND SPECIFICATIONS OF A WATER HYDRAULIC SERVO VALVE The cooperation work with In-LHC will start with a study of the influence on the design, geometry and material choice due to the use of tap water as fluid medium for the servo valve. Components of the servo-valve, will be sorted in 3 classe: - Components non-affected by the change from oil to

water and that will remain unchanged. - Slightly affected components with existing and reliable

technological answers. These are the components already identified has needing changes but in any case this changes will not compromise the success of the operations.

- Critical components that will need special attention.

Either because they are the main components of the servo-valve or because their behaviour with water could be seriously affected. These components are considered as “key-components” and the biggest part of the work will be focused on these components.

The impact of the changes in the physical properties (density, viscosity, effect of cavitation, coexistence of water and steam...) will also be checked. Engineering solution will have to be provided for areas that already seem requiring spaceial care: wear and corrosion resistance, static and dynamic sealing. Special procedures will have to be tested for storage of the components during period of inactivity. According to the results of that study a proposal for a new design of servo-valve will be made. REPORTS AND PUBLICATIONS - STR/00RT.024 "IN-LHC Servovalve 1900687

Spécification d'une servovalve pression 4 voies" F. LOUVEAU - 28 septembre 2000.

- DPSA/STR/LTO/00RT.096 Rev 0. "Design and launch

manufacture of the pressure valves" F. LOUVEAU - 5 jan 2001.

- DTSI/SRSI/LPR/01RT.043 Results on qualification of a

pressure servo-valve for force feedback applications. Y. Measson, O. David.


- DTSI/SRSI/LPR/02RT.008 Qualification of a Maestro arm equipped with pressure servo-valves. Y. Measson, O. David.

- DTSI/SRSI/LPR/02RT.071 Upgrade of the torque

model used in the control of hydraulic manipulators Y. Measson, O. David.

- DTSI/SRSI/LPR/03RT.071 Presentation of the new

generation of Maestro arm and specifications for a water-hydraulics servo-valve - Y. Measson, O. David.

- DTSI/SRSI/LPR/03RT.088 Review analysis of water

hydraulics needs in a fusion reactor like ITER- O. David (to be published).

- DTSI/SRSI/LPR/04RT.010 Integration of pressure

servo-valves on the Maestro manipulator - Y. Measson, O. David (to be published).

- Y. Measson, O. David, F. Louveau, J.P. Friconneau .

technology and control for hydraulic manipulators. 22th SOFT conference. September 2002. Helsinki. Finland.




UT-VIV/AM-ECIr Task Title: REMOTE HANDLING TECHNIQUES Radiation effects on electronic components INTRODUCTION The availability, at the end of year 2003, of commercial SiGe transistors manufactured by INFINEON, made it possible to complete the studies undertaken in 2002. Let us recall that this recent technology is more and more used in cellular phones. Moreover, it could replace GaAs and ECL technologies which are often used in the design of hardened transmission systems. A validation mock-up was produced and is being irradiated. During this year, we also studied the behaviour under radiation of the optoelectronic components used for shaft or absolute position encoders. Although more rarely used in robotics than for coding by resolvers, these encoders have the advantage, in this particular context of strongly irradiant medium, to offer a greater facility of embedded digitalization and to contribute to the reduction of the number of wires towards the control room. 2003 ACTIVITIES SIGE COMPONENTS The availability of elementary industrial SiGe transistors has allowed to follow investigation on such components. Within the framework of remote handling robotics for civilian nuclear industry, the HF communication can be divided into three fields: - hertzian data transmission towards the mobile systems, - carrier current transmission where data and supply use

the same channel, - data transmission by an optoelectronic channel (optical

fibres and end components) which requires the amplification of the sensor’s signal as a preliminary.

The electronic components usually met are based on bipolar ECL or GaAs technologies. The obsolescence or the difficulties to use them in the encountered specific environment naturally leads to the study of SiGe technology, which are widely used for cellular phones. We retained, in a first study, the components presented in table 1. They remain sufficiently elementary to apprehend the behaviour in hard environment and make it possible to build some simple functions for data transmission.

Table 1 : Selected components for the experiments

FP620 Low Signal Transistor

Old Technology

BFP640 Low Signal transistor

BFP650 Power Transistor

BGA622 Low Signal Amplifier

Recent technology

A preliminary parametric study, before irradiation, of BFP620 and BFP640 transistors led to the following results.

0,0E+00

1,0E-02

2,0E-02

3,0E-02

4,0E-02

0 0,5 1 1,5 2Vce (V)

Ic (A

)

Figure 1 : BFP620, Ic = f(Vce) for ∆Ib = 25 µA Curves of figure 1 and figure 2 show the collector Ic current fluctuation of the BFP620 according to the tension Vce and to the base-emitter current Ib. One checks that the gain ß = Ic/Ib remains higher than 100 which is in conformity with the data-sheet of the manufacturer.

0,0E+00

5,0E-04

1,0E-03

1,5E-03

0 0,5 1 1,5 2 2,5Vce (V)

Ic (A

)

Figure 2 : BFP620, Ic = f(Vce) for ∆Ib = 1 µA


The curve of figure 3 represents the characteristic of the junction base-transmitter Ib = f(Vbe). The threshold level of the transistors is close to 0,8 V.

0,0E+00

2,5E-03

5,0E-03

7,5E-03

1,0E-02

0 0,2 0,4 0,6 0,8 1Vbe (V)

Ib (A

)

Figure 3 : BFP620, Ib = f(Vbe) for Ic = 0 mA One will notice the similar behaviour of the junction of the BFP640 (figure 4).

0,0E+00

2,5E-03

5,0E-03

7,5E-03

1,0E-02

0 0,2 0,4 0,6 0,8 1Vbe (V)

Ib (A

)

Figure 4 : BFP640, Ib = f(Vbe) for Ic = 0 mA Curves of figure 5 and figure 6 show the collector current Ic fluctuations for the BFP640 according to the tension Vce and to the base-emitter current Ib. One checks that the gain ß = Ic/Ib remains higher than 100 which is in conformity with the data-sheet of the manufacturer.

0,0E+00

1,0E-02

2,0E-02

3,0E-02

4,0E-02

5,0E-02

0 0,5 1 1,5 2 2,5Vce (V)

Ic (A

)

Figure 5 : BFP640, Ic = f(Vce) for ∆Ib = 50 µA After these static tests, a mock-up was built in order to carry out a first experiment under radiation.

0,0E+00

1,0E-05

2,0E-05

3,0E-05

4,0E-05

5,0E-05

6,0E-05

0 0,5 1 1,5 2 2,5Vce (V)

Ic (A

)

Figure 6 : BFP640, Ic = f(Vce) for ∆Ib = 50 nA

Figure 7 : Mock-up of BFP620 for radiation experiment The selected design polarizes the component according to the recommendations of the manufacturer. It amplifies the input sinusoidal signal Ve and provides an output signal Vs as shown on the oscilloscope chronogram of figure 7. The experiment will examine the Vs/Ve ratio. As a direct function of the gain ß of the transistor, it will make it possible to appreciate the awaited drift of this parameter under the effects of the radiations. The experiment is currently under progress. END COMPONENTS FOR OPTICAL ENCODERS COTS photoelectronic components have already been invited for the design and industrial-scale production of a small series of angular position encoders able to withstand a dose of 300 kGy[Si]. As part of encoder development, MICROTEL has designed a dedicated photoreceiver with eight phototransistors forming a common collector circuit. In such systems, bit coding relies on a photoemitter and optical disk tracks associated with a reticle to provide four pairs of differential light signals to the photoreceiver. For the experiment, five photoemitter-receiver coupled pairs – infrared emitters and MIC1758 receivers – were used to test their radiation response (see figure 8).

SiGe BFP620


Some work has already been performed on the same type of photoreceiver [1][2]. The study described here focused on measuring two characteristics: dark current and emitter-receiver transmission coefficient, both as a function of the total dose. In the second case, it was assumed that parametric drifts were attributable to phototransistors only. The light-emitting diodes was previously tested under radiation and exhibited excellent dose tolerances (with variations smaller than 5 %).

Figure 8 : Mock-up of emitter-receiver pair In the present tests, one of the above mentioned emitter-receiver pairs served as a reference, three other were tested under radiation at different bias currents and one was set aside for temperature tests. The three pairs tested for bias current testing were placed in an irradiator with a 60Co source and subject to a dose rate of 50 krad[Si]/h. The test bench (see figure 9) comprises a PC with data acquisition and transmission cards, together with a rack that houses power supply and biasing electronics as well as a measured signal multiplexer. This rack is linked by cable to the facility in which the sample components are irradiated. The PC incorporates data acquisition cards for signals produced by the multiplexer. Card digital ports are allotted to multiplexer control. A second, PC-mounted, digital input/output card actuates the relay switches that supply power and route bias currents to the appropriate test cards.

TEST BENCH Multiplex er

Relay card

PC

Power supplies Bias voltages

PHOTOEMITTERS - RECEIVERS

IRRADIATOR

Figure 9 : Test bed for optoelectronic components

The online bench can simultaneously accommodate two emitter-receiver pairs, each comprising an LED and eight phototransistors included in the same receiver. Tests focused on the total dose responses of control currents (IE) needed to produce seven output current values (0.01 - 0.05 – 0.1 - 0.5 - 1 - 5 and 10 mA) in each phototransistor, at the constant VCE value of 2.5 V. The two emitters were biased under irradiation and between measurements at two different currents: 0 and 80 mA. This procedure facilitates the assessment of bias current impact on phototransistors behaviour during irradiation. The light-emitting diodes had been previously radiation tested and exhibited excellent dose tolerances (with variations smaller than 5 %). Some results are given below. Figure 10 shows changes in the variation of the emitter control current versus total dose for the seven phototransistor output current values, with the emitter-receiver pair biased at 80 mA between measurements. Up to a dose of 3 Mrad[Si], there is a fairly steady increase in the IE required to produce the desired IR values. At the end of this initial phase and up to the maximum total dose (30 Mrad), IE tends to level off. The IR values of 5 to 10 mA were such that these values could no longer be achieved at doses over 0.1 and 1 Mrad[Si]. As dose increases, an increase in IE is also necessary to counteract the degradation of the phototransistor gain and response. Previous studies had shown a significant degradation of the transmission coefficient [3].

0,1

1

10

100

0,001 0,01 0,1 1 10 100

Total Dose (Mrad[Si])

I E (m

A)

IR (mA)

1051

0.50.10.050.01

Figure 10 : Results for an infrared emitter - MIC1758 pair irradiated at a dose rate

of 50 krad[Si]/h for 7 IR. currents Bias current applied during irradiation: IE = 80 mA

Figure 11 shows the transfer functions of three emitter-receiver pairs irradiated at 30 Mrad[Si]. These values were obtained by averaging measurements taken for all 8 phototransistors in a receiver. The best phototransistor behaviour is achieved for a bias value of 80 mA. In this configuration, an average 5 mA can be obtained in the receiver, which is not possible with the other two bias values. Based on the resulting curves, IR currents of 2 to 3 mA are the maximum achievable values at the dose level tested, regardless of bias value, for an IE range from 0 to 100 mA.

Eight-photoreceivers dye

Photoemitter dye


0,01

0,1

1

10

0 20 40 60 80 100

IE (mA)

I R (m

A)

Ie = 80mAIe = 0Not supplied

Bias during irradiation

Figure 11 : Transfer functions of three emitter – MIC1758 pairs irradiated to 30 Mrad[Si]

under various bias currents Other results have been published on [4]. CONCLUSION Tests performed on MICROTEL phototransistors revealed a significant shift in emitter-to-receiver transmission coefficient, which tended to level off above 3 Mrad[Si]. Bias current had definite impact on the radiation response of phototransistors, the worst case scenario being that in which they were not lit during irradiation. However, remote controlled systems equipped with optical encoders should normally execute frequent movements in order to alternate lightening of photoreceivers through the coding disk. Long rest period without any movements should be limited. The next step of this experiment will be the validation under ITER environment with identical components. Scheduled period will be early 2004. SiGe experiments has to start now in order to evaluate the behaviour. Scheduled period will be also early 2004. REFERENCES [1] H.Lischka, “Gamma and Neutron Irradiation of

Optoelectronic Devices,” RADECS95 Proceedings, Arcachon, France, September 18-22, pp. 560-563.

[2] Andrew Holmes-Siedle and Len Adams, “Handbook

of Radiation Effects,” Oxford Science Publications. [3] H.Lischka, “Radiation effects in light-emitting diodes,

laser diodes, photodiodes and optocouplers,” IEEE Trans. on Nuclear Science, 1994, p. 226.

[4] Characterization of photoreceivers for a rad-hard

optical shaft encoder J-P. Le Gac, A. Giraud RADECS Conference 2003.

TASK LEADER Alain GIRAUD DRT/LIST/DTSI/SARC/LCSD CEA-Saclay F-91191 Gif-sur-Yvette Cedex Tél. : 33 1 69 08 64 30 Fax : 33 1 69 08 20 82 E-mail : [email protected]


UT-VIV/AM-vacuum Task Title: REMOTE HANDLING TECHNIQUES Technologies for vacuum and temperature and magnetic field

conditions for remote handling systems INTRODUCTION This project takes place in the Underlying Techniques (UT) for Remote Handling (RH) activities for the next step of the fusion reactor ITER. In-Vessel Inspection devices are being studied and developed within the L7 Project to perform inspections inside the ITER Vessel. They intend to perform an inspection operation under vacuum and temperature. Due to the requirements to operate the Magnet system, inspection under magnetic field is being required recently. The combination of severe conditions induces high limitations in the technology available. As an inspection device requires use of joints to operate properly in a reactor like ITER, a review of feasibility is required to assess this issue. The maintenance work of the system involves handling for inspection purpose under the condition just after Shutdown of the machine. In-Vessel conditions induce to sustain Vacuum, high temperature, dose rate and high-level magnetic field. First phase of the work concerned the analysis of the requirements to perform a realistic operation inside the Vacuum Vessel conditioning with ultra high vacuum, temperature and magnetic field. Second phase focused on the analysis of the influence of the magnetic field on the components involved in the design of a remote handling system and reviewed the technologies available for these components. 2003 ACTIVITIES REQUIREMENTS FOR VACUUM AND TEMPERA-TURE & MAGNETIC IN RH The maintenance work of the system involves handling for inspection purpose under the condition just after Shutdown of the machine. In-Vessel conditions induce to sustain Vacuum, high temperature, dose rate and high-level magnetic field.

The most critical components require to sustain the following conditions : - Vacuum : 10-7 Pa with pollution avoidance. - 120°C (including 240°C of baking temperature). - Magnetic field from 4 to 8 T. The first step was to define clearly the system and its environmental constraints with an environmental function analysis. Then functions were decomposed in under-functions to come to generic technologic solutions with a function analysis system technique. The mix of the 2 previous analyses allowed us to dispatch the environmental constraints on each generic technologic solution. Finally, we have classify the generic technologic solution by importance with regards to the environmental constraints. Main identified issues are structure, actuators, position sensors, and data / energy transfer which should be fully compatible with ITER most severe constrains of vacuum, temperature, magnetic field and radiations REVIEW ANALYSIS OF TECHNOLOGY The following step of the study was to inventory all the alternatives to each generic technologic solution. It also compared these alternatives together and to the environmental constraint requirements. First part of analysis concerned the usable materials to design the robot structure The designers need a list of the compatible materials and their behaviours in the Tokamak : the objectives are to define the maximal mass force designated by a typical material in these conditions. Therefore, it is possible to determine the mass of this material usable in the robot. The goal then is not to calculate the precise resulting force on a material with specific geometry but to give an approximation of the maximal practical mass force for a given material. Dia- or paramagnetic materials are not very sensitive to the magnetic fields. The magnetic force increases with the field B = [4-8 T], but remains inferior to the weight. It is directed in the radial direction to the central axis (paramagnetic) or to the outside (diamagnetic) of the torus.


The less the magnetic susceptibility χ will be, the less the material will be submitted to the magnetic force: for example, we can use any quantity of titanium, but 1 kg of stainless steel will be submitted to a 1 daN magnetic force. For a ferromagnetic material, the radial magnetic force towards the axis of the torus will increase with the field B = [4-8 T] and will be several time greater than the weight P: - F = [10*P – 45*P] for the iron. - F = [8*P – 32*P] for the cobalt. - F = [P – 10*P] for the nickel. The magnetic forces are very great on ferromagnetic materials, we must limit these materials to the minimum. Due to the saturation of ferromagnetic materials, it is impossible to use magnetic shields: these, completely saturated, would be without effect, and furthermore, will be subjected to great magnetic forces. Second part of the analysis focused on the influence of the magnetic field on the electrical conductors A 1 m long conductor in which a 1 A current circulates has to face a maximal force of 4 to 8 N according to its position in the torus due to electromagnetic force. To avoid important forces on the conductors, we must limit I. To avoid torques on conductors with a strong current, we can place together the input and output wires. So the forces will cancel themselves and will not result in having supplementary forces on the robot due to the conductors. Furthermore, to put together the input and output wires will minimizes current loop surfaces, and thus the induced tensions (Electro-Magnetic Compatibility). An electrical conductor moving in a static magnetic field or in a gradient of magnetic field is submitted to an induced tension. If the magnetic field is constant in the time and space, we can calculate easily an order of magnitude for the tensions induced in the conductors, by their displacement in the field. The first case of induction is due to the displacement of a rectilinear conductor in the field, the second to a surface variation of a loop seen by the field. A linear conductor moving in a 8 T field at a low speed (< 10 cm/s) is submitted to an induced tension of around 1 V. For a loops of conductors which rotates slowly (< 1 rpm), the induced tensions are weak (< 0.05 V). Low-voltage components or components needing a stable voltage (sensors, electronics…) of about 1 Volt (∆U ≈ 1 V/m) must be avoided or must pass a compatibility study.

To minimize the induced tension when the robot is moving, we must have B

rapproximately perpendicular to the loop

plane. So we must position the loop vertically and maintain it in this position, otherwise without maintain, the magnetic forces will make the loop rotate from its position. And if the loop slightly rotates, the variation of surface seen by B

r

will give an induced tension. A gradient of magnetic field has the same effect than a moving conductor in a static field. For example, the shut down of ITER magnets corresponds to a speed of a conductor of around 40 cm/s. Last part of the analysis concerned the actuators With such a magnetic field, magnets are unusable (and destroyed). Furthermore, electromagnets are too weak in comparison with the field : ferromagnetic materials are all saturated from 2 T. So the principle of asynchronous and synchronous motors is unusable because it is impossible to generate magnetic field which rotates with electromagnets. The use of an induction DC motor (coiled rotor with a collector, coiled stator) is perhaps possible (if such a small induction DC motor exists !). When there is the external magnetic field we can deactivate the electromagnets of the stator. Without field, we can active the electromagnets to run the motor. There is only one solution with the electromagnetic motor technology, but with 2 alternatives: a DC rotor with collector or a whole induction DC motor with a separate electromagnet excitation. The DC motor is a possible actuator solution in our environment conditions although the technical difficulty is of its positioning. But this solution is not very flexible because it depends on the magnetic field vector : norm, direction. As a consequence, this possible solution needs a further study in relation with a motor manufacturer, and the development of a specific motor (not standard). Thus, a financial investment would be needed. A usable hydrau-pneumatic technology is water hydraulics. It presents the great advantage to be a classical robotic technology insensitive to the magnetic field. But this technology (in development) does not yet support the temperature requirement. This problem shall be raised in coordination with the constructors. None of the non-conventional actuators can be used properly for a macroscopic standard robotic need : precision, speed, force and robustness Only piezoelectric technologies could be used for limited actions : not to move a robot arm, but on an extremity tool, where we need precision, limited movements and small forces


CONCLUSIONS The technologies used to design a robotic device were analysed to determine their suitability in magnetic field environment. Some non robotics technologies usable under magnetic field were also analysed to determine their suitability in the robotics design. The next steps of this study are the manufacture and testing of a completely integrated vacuum prototype to be tested under ITER relevant conditions. REFERENCES [1] European Fusion Technology Programme - Task UT-

VIV AM Vacuum “Technologies for vacuum and temperature and magnetic field conditions for remote handling systems" June 17th, 2002.

REPORTS AND PUBLICATIONS Report DTSI/SRSI/LPR 03RT 053 UT VIV AM Vacuum, “Requirements for vacuum, temperature and magnetic field technologies in remote handling”. Report DTSI/SRSI/LPR 03RT 102 UT VIV AM Vacuum, “Review analysis of technologies”.



Documents

Annual Report of the Association EURATOM/CEA 2003