NEA Mandates and Structures

Expert Group on Physics of Reactor Systems (EGPRS)

Mandate (Document reference):

• The NSC Working Party on Scientific Issues of Reactor Systems (WPRS): Proposal for Prioritisation and Restructuring [NEA/NSC/WPRS/DOC(2020)19]
• Summary record of the 31^st meeting of the Nuclear Science Committee in September 2020 [NEA/SEN/NSC(2020)20] 
• Mandate of the WPRS Expert Group on Physics of Reactor Systems (EGPRS) [NEA/NSC/WPRS/DOC(2021)1]

Mandate (Document extract):

Extract from document  [NEA/NSC/WPRS/DOC(2021)1]

Background

As a result of the prioritisation process, a reorganisation of NSC activities was performed under the guidance of the NSC Bureau. This has resulted in the disbandment of the NSC Expert Group on Multi-Physics Experimental Data, Benchmarks and Validation (EGMPEBV), the Expert Group on Radiation Transport and Shielding (WPRS-RTS), the Expert Group on Reactor Physics and Advanced Nuclear Systems (WPRS-RPANS) and the Expert Group on Uncertainty Analysis in Modelling (WPRS-UAM). Two new bodies have been created to replace them: the Expert Group on Physics of Reactor Systems (WPRS-EGPRS) and the Expert Group on Reactor Systems MUlti-Physics (WPRS-EGMUP).

Scope

Under the guidance of the Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems (WPRS), the Expert Group on Physics of Reactor Systems (EGPRS) will perform specific tasks associated with neutronics, radiation transport, reactor physics and nuclear fuel feedback along with uncertainty analysis of present and future nuclear power systems. The considered reactor systems that will be studied include but are not limited to:

• current fleet of light-water and heavy water reactors (LWRs/HWRs) as well as present generation of fuel designs;
• evolutionary and innovative LWRs/HWRs along with advanced and/or accident tolerant fuel designs;
• next generation of core and fuel assembly designs,including water cooled small modular reactors (SMRs),micro-reactors, high temperature gas cooled reactors (HTGR) as well as advanced fast spectrum systems including sodium fast reactors (SFRs) and molten salt reactor systems (MSRs);
• accelerator driven (sub-critical) and critical systems for waste transmutation as well as fusion systems.

Objectives

The objective of the EGPRS is to provide expert advice to the WPRS and the nuclear/accelerator community on the development needs (data and methods, validation experiments, scenario studies) for neutronics and fuel feedback issues of different reactor systems.

The fulfilment of this objective notably entails providing specific technical information on:

• core reactivity characteristics, including fuel depletion effects;
• core power/flux distributions;
• core dynamics and reactivity control;
• fuel physics feedback modelling and effects;
• fluence, shielding and dosimetry aspects of reactors, accelerators and target irradiation facilities;
• uncertainty analysis of the above.

This technical information will generally be derived from a combination of direct experimental evidence and/or the results of theoretical benchmark analyses using accurate, validated modelling and simulation (M&S) methods. In either case, the availability of suitable experimental data is a fundamental requirement. The EGPRS will monitor gaps and steer development of the International Radiation Shielding Experiments Database (SINBAD) in collaboration with the United States’ Radiation Safety Information Computational Centre (RSICC).

Working methods

The EGPRS will report to the Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems (WPRS). The EGPRS will meet once per year, with additional meetings in support of particular activities such as task forces reporting to the EGPRS.

Links to other NEA bodies and international projects

The EGPRS will maintain close collaboration with the Expert Group on Reactor Systems MUlti-Physics (EGMUP), the Expert Group on Reactor Fuel Performance (EGRFP) as well as the Working Party on Nuclear Criticality Safety (WPNCS). Close links will be maintained with other data preservation projects notably the International Reactor Physics Experiments Evaluation Project Technical Review Group (IRPhE) and the Technical Review Group for the International Criticality Safety Benchmarks Evaluation Project (ICSBEP) as well as with the International Fuel Performance Experiments (IFPE) database. The EGPRS should also work in co-ordination with the Joint Evaluated Fission and Fusion Nuclear Data Library Co-ordination Group (JEFF) under the Management Board for the Development, Application and Validation of Nuclear Data and Codes (MBDAV) and with the Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF) community of accelerator shielding specialists. Where required, the EGPRS will provide safety scenario studies for advanced systems and fuels. In this context, it will liaise closely with the Working Party on Scientific Issues of Advanced Fuel Cycles (WPFC).

Deliverables

The EGPRS future deliverables include:

• a review of fast MSR physics issues;
• to complete FHR Phase-I benchmark;
• a State-of-the-art report on 3D radiation transport codes and methods;
• the contribution to the ICSBEP Technical Review Group activity for the shielding chapter;
• the specification for Deterministic Time-Dependent Neutron Transport Benchmark C5-G7-TD without Spatial Homogenisation for Phase II and Phase III;
• the organisation of C5-G7-TD benchmark meeting;
• to co-ordinate the organisation and publish the proceedings of the 15^th Workshop on Shielding Aspects of Accelerators, Targets, and Irradiation Facilities (SATIF) scheduled to take place in September 2021;
• to complete Phase I (core neutronics) of LWR-UAM Benchmark;
• to complete Phase II of LWR-UAM Benchmark;
• to complete Phase I of SFR-UAM;
• to complete Phase II of SFR-UAM;
• to organise LWR-UAM and SFR-UAM benchmark workshops.