NEA Mandates and Structures
Expert Group on Uncertainty Analysis in Modelling
Tomasz KOZLOWSKI, United States
|Member(s):||All NEA member countries|
Under the NEA Statute
International Atomic Energy Agency (IAEA)|
|Date of creation:||30 June 2010|
|End of mandate:||30 June 2020|
Mandate (Document reference):
- Agreed at the 21st Meeting of the Nuclear Science Committee in June 2010 [NEA/SEN/NSC(2010)3]
- Revised at the 9th meeting of the Working Party on Scientific Issues of Reactor Systems [NEA/SEN/NSC/WPRS(2012)7]
- Extended as a part of WPRS activities at the 23rd meeting of the Nuclear Science Committee in June 2012 [NEA/SEN/NSC(2012)3]
- Extended and revised at the 11th meeting of the Working Party on Scientific Issues of Reactor Systems [NEA/SEN/NSC/WPRS(2014)2/REV1]
- Extended and revised at the 13th meeting of the Working Party on Scientific Issues of Reactor Systems [NEA/SEN/NSC/WPRS(2016)2]
- Mandate of the Expert Group on Uncertainty Analysis in Modelling [NEA/SEN/NSC/WPRS(2018)3]
- Extended and revised mandate at the 15th meeting of the Working Party on Scientific Issues of Reactor Systems [NEA/NSC/WPRS/DOC(2018)9]
Mandate (Document extract):
Extract from document [NEA/SEN/NSC/WPRS(2018)3]
Under the guidance of the Working Party on Scientific Issues of Reactor Systems (WPRS) the Expert Group on Uncertainty Analysis in Modelling (EGUAM) will perform specific tasks associated with uncertainty analysis in modelling of coupled multi-physics analysis of present and future nuclear power systems. Reactor types considered include, but are not limited to the following:
- Present generation light-water reactors (LWRs) and heavy-water reactors (HWRs) with advanced and innovative fuels, evolutionary and innovative LWRs and HWRs.
- High-temperature gas-cooled reactors (HTGRs).
- Sodium cool Fast Reactors (SFRs).
- Fast-spectrum systems and advanced reactor systems.
The expert group will provide advice to the WPRS and the nuclear community on the scientific development needs (data and methods, validation experiments, scenario studies) of sensitivity and uncertainty methodology for modelling of different reactor systems and scenarios.
The main activity will be focused on uncertainties in modelling LWR transients. In this context the objectives will be:
- To determine modelling uncertainties for reactor systems under steady-state and transient conditions, quantifying the impact of uncertainties for each type of calculation in the multi-physics analysis, i.e.:
- neutronics calculations;
- thermal hydraulics modelling;
- fuel behaviour;
- To determine for each of the aforementioned types of calculation the major sources of uncertainty, arising from:
- data (e.g. nuclear data, geometry, materials);
- numerical methods;
- physical models;
- To develop and test methods for combining the above mentioned sources of uncertainty for each type of calculation so as to yield uncertainty assessment for the coupled multi-physics analyses;
- To develop a benchmark framework which combines information from available integral facility and NPP experimental data with analytical and numerical benchmarking:
- where available, experimental data will be used to test the individual types of calculation as well coupled multi-physics simulations.
The deliverables of the EGUAM will include the following:
- Publish final report Phase I (core neutronics) of UAM Benchmark for BWR, PWR and VVER.
- Complete Phase II (core thermal-hydraulics) of UAM Benchmark for BWR, PWR and VVER.
- Release specifications for Phase III (coupled system thermal-hydraulics/core 3D kinetics) UAM Benchmark for BWR, PWR and VVER.
- Complete Oskarshamn-2 Reactor Stability Benchmark.
- Organisation of Workshop on EGUAM benchmarks.
- Specifications on Sodium cooled Fast Reactor (SFR) transient analysis benchmark.
- State-of-the-art report on Natural Behaviour of Sodium Cooled Fast Reactor under Unprotected Transients as a Function of Fuel Nature and Core Size.
- Syntheses of the UAM-SFR results and Recommendations for Completion of the BEPU Process.
- Complete final report Phase I exercises (steady state exercises) of the modular high temperature gas reactor (MHTGR) Benchmark.
- Complete Phase II exercises (transient exercises) of MHTGR Benchmark.
- Complete Phase I of Pressurised Heavy Water Reactor (PHWR) thermal-hydraulics Benchmark.
The EGUAM will meet once per year, in connection with WPRS meetings. An annual Workshop on Uncertainty Analysis in Modelling in Reactor Systems will be organised, in connection with the related benchmark activities.
Links to other groups
The EGUAM will liaise closely with the NEA NSC Expert Group on Multi-physics Experimental Data, Benchmarks and Validation (EGMPEBV). The EGUAM will work in co-ordination with the WPNCS Expert Group on Uncertainty Analysis for Criticality Safety Analyses (UACSA) and with the CSNI Group on Analysis and Management of Accidents (GAMA). The EGUAM will also work in co-operation with the IAEA HTR UAM Coordinated Research Project (CRP).