Core design of the next-generation sodium-cooled fast reactor in Japan

Kan, Taro*; Ogura, Masashi*; Hibi, Koki*; Oki, Shigeo ; Maeda, Seiichiro ; Maruyama, Shuhei   ; Ohgama, Kazuya   

In Japan, a 1500MWe-scale sodium-cooled fastreactor (FR) has been designed as a commercial phaseFR for utilizing in an equilibrium FR operation era, and a 750MWe-scale FR has been as a demonstration phase FRfor realizing the commercial phase FR. Thedemonstration phase core adopts a core and a blanketfuel subassembly with the same specifications of thecommercial phase core, and is designed to satisfy designrequirements, especially to accept a broad range of fuelcompositions, which arises in a transition period from anLWR are to an FR era. By optimizing an arrangement offuel subassemblies and control rods, and employing a fluxadjuster, the demonstration phase core gets flat powerdistribution giving high core performances. And its coreand fuel specifications are materialized to satisfy thedesign requirements desired for the next-generation FR.