Upload
others
View
9
Download
0
Embed Size (px)
Citation preview
| This work was part funded by the RCUK Energy Programme [grant number EP/P012450/1]. This work has been carried out within the
framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under
grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.
Nuclear data needs and
applications in fusion researchLee W. Packer, M. R. Gilbert, B. Colling, T. Eade, J. Naish, C. R. Nobs, T.
Stainer, A. Valentine, O. Vilkhivskava+ other contributors
|
1. Introduction – fusion and nuclear simulation needs
2. Nuclear codes and data to predict nuclear phenomena
• Radiation transport codes
• FISPACT-II inventory code
• Nuclear data – JEFF, FENDL, TENDL
• Benchmarking
3. 14 MeV experimental benchmark activities
• Decay heat validation using the JAEA FNS decay heat experiments
• Technological exploitation of JET operations
• Activated water coolant (N-16 and N-17) measurements
• Tritium breeding mock up experiments
Overview
JEFF stakeholders workshop 6-7 June, Paris 20192
|
Culham Centre for Fusion Energy
JET
MAST-U
Fusion research arm of UKAEA
| Slide 4
DONES
JT-60MAST-U
Fusion mission: roadmap
|Slid
e 5
Role of neutronics and nuclear data in fusion
17 Feb 2014
• Neutrons will be present in very large quantities in DT fusion
devices – >1.8E20 n/s in the ITER plasma
• This reaction releases 17.6 MeV, 80% of this energy is taken
by the neutron.
– Vitally important to know where the neutrons go, how much energy is
deposited in materials, levels of activation…
• Neutronics involves the simulation of nuclear effects in matter
through various nuclear interaction mechanisms.
• Predictions rely on nuclear data
• For fusion device design, safety and performance there is a
need to calculate essential nuclear quantities:
– Nuclear heating (from neutrons inducing interactions that heat
components)
– Activation of materials and waste arisings
– Gamma shutdown dose rates due to neutron activation of
materials (relevant to maintenance operations)
– Nuclear damage and gas production (neutron reactions cause
displacements and produce He, which affect material properties)
|
ITER nuclear modelling and analysis
6
• Modelling performed from detailed CAD models and simplified to semi detailed level before integration into MCNP via a universe implementation.
• Use MCNP6 for RT simulation but we are testing alternatives such as SERPENT
• FENDL 3.1c and d is the reference library for ITER analysis
Integrated reference model (C-Model
R180430)
Envelope structure contains each
Tokamak component individually
Single blanket module
HNB3
Examples of simplified sub-models
Work by Alex Valentine
Plotted using D1SUNED
JEFF stakeholders workshop 6-7 June, Paris 2019
|
beryllium pebbles
lithium silicate pebbles
< European dual-coolant
blanket concept [FZK].
European helium-cooled
pebble-bed blanket
[FZK]. >
DEMO: Tritium Breeding Blankets
|
Neutron spectra in tokamaks
• 14 MeV fusion neutrons lose energy by elastic and in-elastic scattering
events with material in the device surrounding the plasma
• Hence even at the first wall there will be a large range of neutron energies
• In ITER the first wall flux will be around 1x1015n/cm2/s from DT fusion.
M Gilbert et al., Neutron-induced transmutation effects in W
and W-alloys in a fusion environment, Nucl. Fusion 51 (2011)
2D + 2D →3He + n (Q = 3.27
MeV)
2D +3He →4He + 1H (Q = 18.3
MeV)
2D + 3T →4He + n (Q = 17.6
MeV)
< Calculated neutron spectra
at the first wall in a DEMO
power plant, in ITER (DT) and
in ITER (DD) plasma
operations
|
Role of simulation tools: predicting radiation
environments
Neutron flux map Activation gamma dose map
Simulations inform on environment – to guide development of suitable technologies
Need to predict:
• Neutron/gamma fields, nuclear heating, damage, gas production
• Activation levels during and after operations, and for decommissioning
considerations
Benchmarking important; DT facilities, JET, SINBAD, validated ND
|
• Serpent-2 and MCNP comparison
Serpent and MCNP Benchmarking
10 JEFF stakeholders workshop 6-7 June, Paris 2019
• Negative cross section values for average heating
numbers (in the ACE files) flags a warning in Serpent
2.
• In particular tungsten (as used in DEMO first wall).
• MCNP reads the same ACE file but does not report
any issue with the negative value.
• It is not clear how Serpent 2 interprets these values
and whether this is the same as MCNP.
• The result is that with Serpent 2 and JEFF (3.2 & 3.3)
data we see negative nuclear heating values in the
range 1-10 MeV and significant differences to MCNP.
• Investigation: negative heating values in W JEFF ace file
|
DEMO waste studies
11 JEFF stakeholders workshop 6-7 June, Paris 2019
• JEFF-3.3 is the reference library for EU DEMO analysis
| Footer12JEFF stakeholders workshop 6-7 June, Paris 2019
Nuclear inventory simulation tools
|
• Validation & Verification (V&V) is an important part of the development and release of the FISPACT-II platform
• A suite of automated validation benchmarks have been created to test new releases of both the FISPACT-II code and the nuclear data libraries
• against international experimental databases
• Results are compiled into open access pdf reports (see fispact.ukaea.uk)
• thousands of pages in total providing a near-complete coverage of the physics landscape for neutron interactions
FISPACT-II V&V
13
|
FISPACT-II validation
14
|
Visualisation of FISPACT-II output
Slide 15
Nuclide chart evolution over time following a fission pulse (decay heat
map)
Calculates the
time evolution
of materials –
under
irradiation and
through
radioactive
decay
http://www.ccfe.ac.uk/EASY.aspx
|
FISPACT-II release and training
• Now at version 4.0 (released February 2018)
• Available at the NEA databank
• New JSON output format for easy (computer) parsing
• Including via python scripts developed as an open-source PYPACT utility(https://github.com/fispact/pypact)
• High energy library extensions from 200 MeV to 1 GeV (HEIR)
• Next course 19-21 June 2019 at the OECD NEA
16
2018 FISPACT-II workshop hosted by the OECD/NEA
databank in Paris
Contact: [email protected]
|17
| Footer18
| Footer19
|20
|21
|22
| Footer23
Integro-differential validation
|
Fusion experiments: Technology
exploitation at JET
JEFF stakeholders workshop 6-7 June, Paris 201924
Irradiation of real ITER materials (ACT)
• New irradiation station assembly to be irradiated at JET 26 positions are filled with a variety of dosimetry foils from 4 institutes (ENEA, CCFE, NCSRD, IFJ) and a selection of ITER materials
• Detailed analysis from previous characterisation work under the collaboration. See Nuclear Fusion 58 (9) 2018 096013
Neutronics experiments (NEXP)
• New sensitivity study for aspects of JET model – results to be compared with SDDR and streaming measurements.
• Detector calibration activity for N-16 measurement – involving Cm-244-C-13 source
Detectors for tritium breeding modules (TBMD)
• Focus on measurement of short-lived products
• Plan to irradiate a selection of dosimetry foils (Bronze, Al90/Ce10, Nb, Cr, In) at the KN2 6U location in the next JET campaign.
|
An experimental campaign at ENEA is expected Nov/Dec 2019 aims to:
• provide a means to validate computational tools and nuclear data
• assess the prediction accuracy in providing fundamental data for the nuclear design, optimization and performance evaluation of DEMO, comprising safety, licensing, waste management and decommissioning issues.
Fusion experiments: Water Cooled Lithium
Lead (WCLL) neutronics mock-up
experiment
25
The nuclear design and performance of breeder blankets fully rely
on the results provided by neutronics calculations.
CCFE have been tasked with diagnostic activities to
support the experiments, primarily dosimetry foils
The foils will be embedded in the experimental region
and used to monitor the local flux.
Following irradiation at ENEA, spectroscopy
measurements will be performed at ADRIANA.
JEFF stakeholders workshop 6-7 June, Paris 2019
|
Fusion experiments: Measurement of 16N
during irradiation of First Wall mock-ups
26
Neutron detector
Gamma detector
The collaboration aims to measure 16N and 17N production in
water activated by DT neutrons and compare with calculations to
reduce uncertainties in the calculation of radiation dose maps due
to activated water.
The main sources of uncertainty currently being due to modelling
and nuclear data, and hence safety factors between 8.2 and 4.7
are applied.
Safety factors applied for the IBED
activated water radiation maps
• Experiment scheduled 24th-28th June
• Project completion: 2nd August 2019
16N reaction rates 17N reaction rates
|
• Nuclear codes and data are essential to develop fusion technology
• Involved in various studies requiring nuclear codes and data to predict nuclear phenomena
• Existing devices, JET, MAST
• Future devices, ITER
• Demonstration power plants, DEMO
• Developing the FISPACT-II inventory code
• Extensive collaborative validation activities
• UKAEA are involved in several collaborative experimental benchmark studies which support this
• Decay heat validation using the JAEA FNS decay heat experiments
• Technological exploitation of JET operations
• Activated water coolant (N-16 and N-17) measurements
• Tritium breeding mock up experiments
Summary
27 JEFF stakeholders workshop 6-7 June, Paris 2019