Aseismatic research on tank type fast breeder reactors

Tank type FBRs are contained in vessels and pipings are omitted. Since liquid sodium around 500 deg C is treated in them, the opposite design requirements of thermal stress design and aseismatic design must be harmonized in their structures. In Japan, the Central Research Institute of Electric Power Industry and Power Reactor and Nuclear Fuel Development Corp. have advanced the development of loop type FBRs, but as the trend in foreign countries, tank type FBRs are adopted as large reactors. Accordingly, the CRIEPI, Hitachi Ltd. and Toshiba Corp. have carried out jointly the examination on the realization of tank type FBRs in Japan in view of their aseismatic capability. The feasibility study was carried out for three years, and completed in March, 1984, thereafter, the research on the practical use was started. As the points to which attention was paid in the aseismatic design, the stiffness design of the thin-walled structures and the hydrodynamic vibration of liquid sodium, structures and internal equipment were taken up. For the qualitative grasp of the aseismatic characteristics of the tank type reactors, the small model experiment was carried out. The structures of the tank type reactors were assumed, and the evaluation of the realizbility was performed. The rationalization of aseismatic structures and the structural reliability will be studied hereafter. (Kako, I.)