Conceptual design study of small sodium cooled reactors

Chikazawa, Yoshitaka  ; Kisohara, Naoyuki ; Usui, Shinichi; Konomura, Mamoru; Tanaka, Toshihiko

A conceptual design of various small metal fuel sodium cooled reactors has been studied in the feasibility study on commercialized fast breeder reactor cycle system. In FY2004 study, a 50 MWe power plant for remote places with a long life core without refueling and a 300 MWe modular reactor which pursues standardization for learning effect and reduction of capital risks.In the small reactor with a long life core, the reactor vessel is minimized without a permanent fuel handling system and the cooling system is simplified adopting 1 loop. The total mass of the reactor vessel and the cooling system is dramatically reduced and the concept has a potential to be an attractive power source for remote places.In the 300 MWe modular reactor, the cooling system adopts 1 loop and the ex-vessel fuel storage tank for spent fuels is eliminated adapting the in-vessel storage (IVS) which has a capacity for a 4 year storage. The reactor building is minimized without the ex-vessel storage This concept has a potential to be an power source for key grids with modular constructions and a first plant with a small fuel cycle facility can demonstrate the metal fuel fast reactor cycle