Decommissioning program of FUGEN and current activities

Tezuka, Masashi  ; Mizui, Hiroyuki ; Matsushima, Akira ; Nakamura, Yasuyuki ; Hayashi, Hirokazu ; Sano, Kazuya ; Nanko, Takashi; Morishita, Yoshitsugu 

FUGEN is a proto-type heavy water moderated, boiling light water cooled, pressure tube type reactor with 165MWe and has been shut downed on Mar. 2003. Following the approval of decommissioning program in 2008, stage of FUGEN was changed to the decommissioning of the facilities. The program consists of following four periods; (1) Spent fuel transportation, (2) Periphery facilities dismantlement, (3) Reactor dismantlement and (4) Building demolition. It is expected that the whole decommissioning will be completed until 2028. As a part of the work in the spent fuel transportation period, the main steam system and the feeder water system etc. are being dismantled in the turbine building. The remaining tritium in the heavy water system is also being removed for facilitating the dismantlement of the heavy water system. Moreover, method on dismantlement of the reactor core is being studied with considering the process under the water for the radiation shielding and the dust suppression.