Research and development on steam generator for fast breeder reactor

The sodium-heated steam generator for a liquid metal fast breeder reactor is one of the most important components, but many problems exist, such as the possibility of sodium-water reaction in the steam generator, the heat transfer characteristics of sodium, the flow instability of water inside heat transfer tubes, the choice of material, etc. Much activity is concentrated for the research and development of the steam generator for ''Monju'' plant which is the first prototype fast breeder, electricity-generating plant in Japan. The basic flow chart, the layout of the plant, the key parameters of the steam generator for ''Monju'' plant are explained. For steam generators, many concepts for heat transfer tubes have been devised, for example helical coil tube, straight tube, U tube, hair pin tube, etc., and each type has advantages and also disadvantages. The research and development works for the steam generator are reviewed in general, and 50 MW steam generator test and many sodium-water reaction tests are described in detail, which have been carried out at Oarai Engineering Center of the Power Reactor and Nuclear Fuel Development Corporation. (Nakai, Y.)