LMFBR coolant system components development in Japan

A review is made on the major components and the research and developments (R and D) of them in the coolant system of sodium-cooled fast reactors in Japan. Two fast reactors, the experimental fast reactor ''Joyo'' and the prototype fast breeder reactor ''Monju'', are being developed as the national project by the Power Reactor and Nuclear Fuel Development Corporation (PNC). In accordance with the project, design, research and development have been extensively made by PNC itself and industries, including in-sodium and water tests of prototype components, characteristic tests, fabrication tests, etc. for both reactors. ''Joyo'' with initial output of 50 MWt is now in preoperational test, while ''Monju'' with 300 MWe is in the stage of check and review by the governmental authority