Remote handling test of Moderators and Reflector in J-PARC MLF

Oi, Motoki; Yamaguchi, Yuji; Teshigawara, Makoto; Naoe, Takashi; Kikuchi, Yoshinori*; Yasuhara, Toshiyuki*; Saruta, Koichi; Kinoshita, Hidetaka; Harada, Masahide

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In the neutron source of the Materials and Life Science Experimental Facility (MLF) in J-PARC, a reflector and three moderators are installed. Life time of the reflector and moderators are designed as 30,000 MWh. Spent moderators and reflectors are highly radioactive, so it must be replaced remotely. It has already been 15 years since the first beam of the MLF. Remote handling test was conducted in 2021 and 2022 using spare moderator and reflector in MLF's hot cell. In the remote handling test, there are some problems to replace irradiated moderators. It was found that there is a risk of damage to the poisoned moderator during installation and removal process. In addition, it was found that some slings were deformed and affected the work. Regarding the confirmed problems, we will make appropriate improvements and conduct a remote handling test again during the maintenance period in 2023. The replacement work of the actual moderators are scheduled to be carried out in 2024.