Status of Monju decommissioning Phase 2, 2; Efforts to reduce sodium risk and rationalize conservation

Fukushima, Tsubasa; Ono, Fumiyasu; Kuramoto, Shimpei; Nishino, Yuki; Nishino, Hajime; Uchihashi, Masaya

"Monju" is a nuclear reactor facility that uses sodium to cool the reactor core. In order to reduce the risk of decommissioning, all liquid sodium in the cooling system piping was transferred to the tank and solidified in order to reduce the range of liquid sodium that may leak. Since this was the first attempt of this project, we dealt with issues such as the assessment of the impact on related equipment, the formulation of dedicated procedure manuals, and various operational changes, and streamlined equipment maintenance due to the reduction of the range of liquid sodium ownership, and summarized the results.