Influence of Great East Japan Earthquake on neutron target station in J-PARC

Sakai, Kenji ; Futakawa, Masatoshi  ; Takada, Hiroshi   ; Sakamoto, Shinichi; Maekawa, Fujio  ; Kinoshita, Hidetaka   ; Seki, Masakazu; Haga, Katsuhiro  ; Kogawa, Hiroyuki  ; Wakui, Takashi  ; Naoe, Takashi   ; Kasugai, Yoshimi  ; Tatsumoto, Hideki; Aso, Tomokazu ; Hasegawa, Shoichi   ; Oikawa, Kenichi   ; Oi, Motoki ; Watanabe, Akihiko; Teshigawara, Makoto   ; Meigo, Shinichiro   ; Ikezaki, Kiyomi; Akutsu, Atsushi; Harada, Masahide   

This report investigates behaviors and damages of each component in a neutron target station of the MLF at the J-PARC at the time of the Great East Japan Earthquake (GEJE). At the date of the GEJE, in the MLF, strong quakes were detected at several instruments, an external power supply were lost, all of the circulation systems were shut down automatically, and a hydrogen gas was released as planned. Leakage of activation liquids and gases did not occur. While, the quakes made gaps between shield blocks and ruptured external pipe lines for air and water by subsidence. But significant damages on the components of the target station were not found though a loss of compressed air supply affected lock systems with air cylinders and pneumatic operation values. These results substantiated a validity of safety design on the target station for emergency accidents.