The NEA Working Party on Nuclear Criticality Safety (WPNCS) deals with the technical and scientific issues relevant to criticality safety, and held its bi-annual meetings in June 2023 at the Agency’s headquarters in Boulogne-Billancourt, France.
The working party’s current focus is set on nuclear data uncertainties in used fuel inventory calculations; the impact of random geometries on (re)criticality; bias estimated from correlated reference experimental benchmarks and robustness of methods; and decay heat at various steps of the back end of the fuel cycle. A recently launched subgroup focuses on the comparison of criticality safety evaluations approaches involving burn-up credit.
The outcomes of the working party’s activities are made publicly available for the benefit of the participating countries. Recent publications include “Burnup Credit Criticality Benchmark Phase IIB: Burnup Calculations of Gadolinium-Bearing Fuel Rods in Boiling Water Reactor Assemblies for Storage and Transportation”, “Role of Integral Experiment Covariance Data for Criticality Safety Validation: EG UACSA Benchmark Phase IV” and “Statistical Tests for Diagnosing Fission Source Convergence and Undersampling in Monte Carlo Criticality Calculations”.
This year marked the 29th series of WPNCS meetings and gathered experts from 17 countries. While the next series of meetings is scheduled in January 2024, the community of experts will have the chance to gather during the upcoming International Conference on Nuclear Criticality, which will take place in October 2023 in Sendai, Japan and is organised by Japan Atomic Energy Agency (JAEA) and supported by the NEA and the WPNCS.
For more information on the working group's activities, visit the WPNCS information page.