Study on reactor core and fuel design of sodium cooled fast reactor (Mixed oxide fuel core); Results in JFY2006

Ogawa, Takashi; Kobayashi, Noboru; Oki, Shigeo ; Naganuma, Masayuki  ; Kubo, Shigenobu* ; Mizuno, Tomoyasu

The sodium-cooled large-scale "high internal conversion (HIC) type" core with MOX fuel is the most promising core concept in FaCT Project in Japan. Design study on core and fuel in JFY2006 is reported. (1) Design study of the core with MOX fuel containing MA; Based on the large-scale HIC type core in FS Phase II, we have developed a core using TRU of high MA content recovered from ALWR spent fuel. MA content in the fuel heavy metal is temporarily assumed to be 3 wt%. We have confirmed the core design feasibility with the detailed evaluations of thermal hydraulic characteristics and fuel integrity. (2) Design study of the nonproliferation core by adding Pu to the blankets; As one of the measures to enhance the intrinsic nonproliferation property of fast reactors, we have developed the nonproliferation core concept that can keep the Pu in blankets to "Reactor Grade (Pu isotope abundance ratio 18%)" with premixing Pu (or TRU) of core fuel to blanket fuel.