Atomic Energy Society of Japan

Developed under the advanced nuclear hydrogen safety research program funded by the Agency for Natural Resources and Energy of the Ministry of Economy, Trade and Industry, a simulation code system based on computational fluid dynamics (CFD) and used to analyze hydrogen behavior including diffusion, combustion, explosion, and structural integrity evaluation to enhance the hydrogen safety performance of the nuclear power plant under severe accident conditions is presented. The functions and utilization methods of the code system mainly through large-scale CFD analyses on hydrogen diffusion and combustion in a containment vessel of PWR is described. The potential contribution of the code system to hydrogen safety in wide-ranging industrial and nuclear fields as well as to continued improvement to severe accident management of nuclear power plants is discussed.