WPNCS Expert Group on Burn-up Credit Criticality Safety

This NEA expert group was set up to examine burn-up credit* as applied to criticality safety in the transportation, storage, and treatment of spent fuel for a wide range of fuel types, including UOX and MOX fuels for PWR, BWR, and VVER.

Under the guidance of the Working Party on Nuclear Criticality Safety, the major assignments of the expert group include:

• carrying out international comparison exercises and benchmarks to assess the ability of code systems to predict the reactivity of spent nuclear fuel systems, including comparison with experimental data as available;
• investigating the physics and predictability of burn-up credit based on the specification and comparison of calculational benchmark problems;
• publishing the results for the benefit of criticality safety community, so that the work may be used to help establish suitable safety margins. 

Ongoing work

• Status of the different benchmarks
  • Benchmark specifications
• Expert group publications and reports
• SFCOMPO: Spent Fuel Isotopic Composition Database
• Burn-up credit bibliography
• Structure of lessons learnt contribution (password required)
• Summary records of BUC 2006 meeting (password required)
• Guidance for BUC (reports in preparation) (password required)

(*) Burn-up credit is a term that applies to the reduction in reactivity of burned nuclear fuel due to the change in composition during irradiation.

Related links

NEA Working Party on Nuclear Criticality Safety

Nuclear Science Committee

E-mail contact: Yolanda Rugama (rugama@nea.fr)

Last updated: 26 July 2008