NEA Mandates and Structures


Working Party on Nuclear Criticality Safety (WPNCS)

Chair(s): Kotaro TONOIKE, Japan
Secretary:  Julie-Fiona MARTIN
(julie-fiona.martin@oecd-nea.org)
Member(s):All NEA member countries*
Russia (Suspended*)
*Russian Federation suspended pursuant to a decision of the OECD Council.
Full participant(s): European Commission
Under the NEA Statute
Observer(s)(International Organisation): International Atomic Energy Agency (IAEA)
By agreement
Date of creation:30 June 1996
End of mandate:30 June 2020

Mandate (Document reference):

  • Agreed at the 7th Meeting of the Nuclear Science Committee in June 1996 [NEA/SEN/NSC(96)3]
  •  Summary Record of the 15th meeting of the Nuclear Science Committee [NEA/SEN/NSC(2004)3]
  • Summary Record of the 18th meeting of the Nuclear Science Committee [NEA/SEN/NSC(2007)3]
  • Extended at the 21th meeting of the Nuclear Science Committee in June 2010 [NEA/SEN/NSC(2010)3]
  • Extended at the 24th meeting of the Nuclear Science Committee, June 2013 [NEA/SEN/NSC(2013)]
  • Extended and revised for one year at the 27th meeting of the Nuclear Science Committee in June 2016 [NEA/SEN/NSC(2016)2]
  • Mandate of the Working Party on Nuclear Criticality Safety (WPNCS) [NEA/SEN/NSC/WPNCS(2017)1]

Mandate (Document extract):

Extract from document [NEA/SEN/NSC/WPNCS(2017)1]

Scope

Under the guidance of the Nuclear Science Committee (NSC), the Working Party will deal with technical and scientific issues relevant to criticality safety. Specific areas of interest include, but are not limited to, investigations concerning static and transient configurations encountered in the nuclear fuel cycle, such as fuel fabrication, transport, separation processing and storage. Areas of activities include:

  • Evaluation of available experimental data, including critical integral experiments and spent nuclear fuel assay data of spent nuclear fuel;
  • Assessment of experimental needs ;
  • Code and data inter-comparison, co-ordination of international benchmark exercises;
  • Development of codes and models, assessment of uncertainties;
  • Development of criticality methodologies and data (including the application of burn-up credit);
  • Study of  uncertainty propagation and quantification analyses for criticality safety assessments;
  • Study of advanced Monte Carlo techniques (including transfer of best practices to practitioners, and the development of convergence, undersampling metrics);
  • Study of criticality of used nuclear fuel (including investigations on degraded fuel, degraded poisons);
  • Study of criticality excursions and criticality accident analyses methodologies.

Objectives

The objectives of the WPNCS are to:

  • Exchange information on national programmes in the area of criticality safety;
  • Guide, promote and co-ordinate high priority activities of common interest to the international criticality safety community, establish co-operations;
  • Develop databases and tools, publish handbooks and reports;
  • Facilitate communications within the international criticality safety community through relevant websites;
  • Co-ordinate WPNCS activities with other working parties within the NEA and in other international frameworks to avoid duplication of activities;
  • Provide a technical basis for other international activities (e.g. ISO, IAEA);
  • Co-ordinate the series of international conferences on nuclear criticality safety (ICNC), held every four years;
  • Monitor the progress of all activities mentioned above and report to the NSC.

Deliverables

The deliverables of the WPNCS for the period 2017-2020 are the following:

1. Evaluations of Integral Experiments, Databases and tools

  • New editions of the International Handbook of Criticality Safety Benchmark Evaluation Project, including updated or new evaluations;
  • Updates to the Database for the International Handbook of Evaluated Criticality Safety Benchmark Experiments (DICE).
  • Release, maintenance and update of the new Spent Fuel Compositions experimental PIE assay database SFCOMPO-2.0.

2. Benchmark Reports (Provisional Titles)

  • Summary report of the findings of the Expert Group on Criticality Excursions Analyses (EGCEA), including Phase II “slow transient” and Phase III “long duration” criticality excursions benchmark reports;
  • Summary report of the findings of the Expert Group on Advanced Monte Carlo Techniques (EGAMT) on “Undersampling in local tallies and clustering effects”;
  • Report on the analysis of the Expert Group on Uncertainty Analyses for Criticality Safety Assessment (EGUACSA) Benchmark Phase II on “Reactivity impacts of manufacturing tolerances of parameters characterizing a fuel assembly configuration”;
  • Report on the analysis of the EGUACSA Benchmark Phase III on “Computation of keff sensitivity coefficients to neutron data”;
  • Report on the analysis of the EGUACSA Benchmark Phase IV on “Correlations between integral experiments”;
  • Report on the analysis of the EGUACSA Benchmark Phase V on “Criticality of MOX damp powders”;
  • Report on the analysis of the Expert Group on Criticality Analysis of Used Nuclear Fuel (EGUNF) Phase I Benchmark on “Study of the reflector effect of silicon dioxide for criticality safety in the direct disposal of used nuclear fuel”; 
  • Report on the analysis of the EGUNF Benchmark Phase II “Gd depletion in BWR fuel”.

Meeting Frequency

 The WPNCS shall meet on average once a year.