Russia’s representatives have taken part in the work of the OECD (Organisation for Economic Cooperation and  Development) and its Nuclear Energy Agency (NEA) for many years. The Nuclear Energy Agency is divided into 8 committees, which set up focused working groups. So the Committee on the Safety of  Nuclear Installations (CSNI) includes the Working Group on Fuel Safety (WGFS). Its work is focused on maintaining and developing the level of knowledge in safe nuclear fuel as based on developed safety criteria and their application to higher burnups, new fuel designs and materials. The assistance rendered by specialists of VNIINM (A.A. Bochvar Research Institute of Inorganic Materials) – one of the leading research institutes of the Russian nuclear industry and leading entity of ROSATOM on problems of the material science and nuclear fuel cycle technology – have significantly advanced solving these problems.

It should be noted that the benchmark calculations in this area of scientific knowledge are carried out for the first time. The input data were the experimental results from four tests that simulated RIA conditions. The experiments were held on high burnup PWR fuel rods in research reactors in Japan and France. The RIA benchmark goal was to compare the calculation results of parameters essential for safety, including criteria-related ones, which were obtained using different codes, and to draw out conclusions on applicability of this or another code. The comparison was done in regard of results obtained through the use of computer codes FALCON, FEMAXI&TRACE, FRAPTRAN, RANNS, SCANAIR, TESPAROD, TRANSURANUS, and RAPTA.

Basing on the RIA benchmark calculations results, NEA OECD produced the report “RIA Fuel Codes Benchmark,” which contains comparative calculation data on gaseous fission product release, temperature and deformations of fuel rods and fuel. Noting with satisfaction, the calculation results obtained through RAPTA-5.2 code demonstrated a good agreement with the experimental data and calculation results gained with codes SCANAIR, FRAPTRAN, FALCON, which have been improved over the long time in frames of the international cooperation. The successful participation in RIA benchmark effort will serve a substantial support to the calculation results obtained using RAPTA-5.2 code that are used in safety justifications in the course of VVER reactors licensing abroad.