Chemical composition of artificial seawater after leaching tests of irradiated fuel

Tanaka, Kosuke  ; Suto, Mitsuo; Onishi, Takashi  ; Akutsu, Yoko ; Yoshitake, Tsunemitsu ; Yamashita, Shinichiro   ; Sekioka, Ken*; Ishigamori, Toshio*; Obayashi, Hiroshi ; Koyama, Shinichi  

In the accident of Fukushima Daiichi NPPs, the water ingress was performed in order to decrease the reactor temperature. At that time, sea water was temporarily used as a coolant and the water contacted with nuclear fuel directly. It can be supposed that fission products (FP) were easily migrated from the fuel to sea water in this situation and that affect the water quality. The knowledge of leaching behavior, therefore, is necessary for evaluating the integrity of reactor component materials such as steels for pressure containment vessel and for reactor vessel. In order to obtain the fundamental knowledge for leaching behavior of FP in the hot sea water, the leaching tests of irradiated fuel were performed and the leachates were subjected to chemical analysis. It is found that he leaching rate of each nuclides obtained in this study were similar to that of the leaching results simulating the underground water.