The development of the safety analysis code for high temperature gas cooled reactor

In Japan Atomic Energy Research Institute, since more than ten years ago, for the purpose of developing the utilization of nuclear thermal energy for other fields than electric power, the research and development of a multipurpose high temperature gas-cooled experimental reactor have been carried out. At present, for the purpose of reducing its construction cost, the rationalizing design is advanced, aiming at a simplified plant. Fuji Electric Corp. in cooperation with Kawasaki Heavy Industries Ltd. tackled the development of the safety analysis code for VHTRs. Hereafter, it is intended to explain the individual codes taking proper opportunity, but in this report, the phenomena for which analysis is required regarding the safety evaluation of VHTRs and the analysis codes for analyzing the phenomena are described. The characteristics of VHTRs, the nuclear-thermal dynamic characteristics of a core, the dynamic characteristics of a plant, the heat removal characteristics after accidents, the oxidation of graphite, the emission of fission products from a core and others are explained. (Kako, I.)