The NEA hosted the ninth annual meeting of the Technical Review Group (TRG) for the International Assay Data of Spent Nuclear Fuel Database (SFCOMPO) on 9 July 2026 at the NEA office in Boulogne-Billancourt, France. The meeting brought together 33 international experts from research organisations, regulatory bodies, waste management agencies, and industry in 12 countries.
SFCOMPO provides data that are essential for validating the computational tools used in nuclear safety and across the nuclear fuel cycle, including applications in reactor physics, criticality safety, radiation shielding and waste management. These data are especially important for fuel cycle analyses, where accurate characterisation of used nuclear fuel supports storage, transportation, recycling, and disposal decisions, including the implementation of appropriate safety, security and safeguards measures.
Meeting participants reviewed progress on the new and ongoing used fuel assay data evaluations and discussed their role in validating used fuel characterisation, fuel depletion modelling, and criticality safety analyses. Presentations covered results from an experimental destructive assay project involving Forsmark-3 boiling water reactor fuel, which was supported by the Spanish Nuclear Safety Council (CSN), Enusa Industrias Avanzadas and the Spanish radioactive waste management agency Empresa Nacional de Residuos Radiactivos (ENRESA), as well as updates on the ongoing evaluation of the BM3 and BM5 datasets from the former ARIANE (Actinide Research in a Nuclear Element) international experimental programme. The TRG also welcomed a new Belgian contribution to SFCOMPO experimental data and associated evaluation activities, linked to the ongoing Rod-Extremity and Gadolinia AnaLysis (REGAL) international experimental programme led by the Belgian Nuclear Research Centre SCK-CEN. Its goal is to provide high-quality assay data for validating pressurised water reactor high-burnup UO2 and low-burnup UO2-Gd2O3 fuel. The group also acknowledged the recent publication SFCOMPO - Evaluation of Fukushima – Daini- 1 Samples -Assemblies 2F1ZN2 and 2F1ZN3 (Type 9×9-9).
A central focus of the meeting was the modernisation of SFCOMPO through migration of the database and related collaborative efforts to NEA GitLab and the development of the new SFCOMPO 3.0 data structures. Participants appreciated the move towards version-controlled, transparent and collaborative workflows. Discussions also addressed future application programming interface (API) needs, access rules and quality indicators for submitted simulation input files.
The group agreed to revive work on decay heat data, explore links with related NEA activities and continue efforts to expand SFCOMPO’s scope and long-term value.
More information on SFCOMPO can be found at SFCOMPO 2.0 (Spent Fuel Isotopic Composition).
