Fuel temperature analyses at overpower of metallic fuel pin for sodium-cooled fast reactors

Mizuno, Tomoyasu; Koyama, Shinichi  ; Kaito, Takeji ; Uwaba, Tomoyuki ; Tanaka, Kenya

Metallic fuel, U-Pu(TRU)-Zr is a fuel candidate for Sodium-cooled fast reactor (SFR) selected as a possible promising future nuclear reactor system in Generation-IV international forum (GIF). Design studies were performed in the Japanese feasibility study on commercialized fast reactor cycle system, and the irradiation behavior of metallic fuel is under investigation through analytical fuel performance code calculations with preliminary analytical models. As fuel temperature analyses at overpower events are also major interest, some calculations of U-Pu(TRU)-Zr fuel irradiation performance were conducted by a simplified calculation program developed in JAEA. The calculated fuel temperature at the maximum power of overpower events, 110-120% of steady state power, was around 1100K in maxim. It is clear that this temperature was low enough to avoid fuel melting in the event.