Liquid leakage from the sea release pipe of the Tokai reprocessing plant; Cause investigation of the leakage, 2; Progress from mechanical damage to the leak

Domura, Kazuyuki; Morimoto, Kenji; Seto, Nobuhiko; Iwasaki, Shogo; Fukuari, Yoshihiro; Inami, Shinichi

A leak occurred from the sea release pipe buried in the bottom of the sea of the Tokai reprocessing plant. The plumbing of the leak point was cut to investigate the cause of the leak and was collected ashore. Then the investigations such as surface observation and other analyses were performed. As a result of this investigation, the plumbing was scratched at the time of construction from the outside. In the service of approximately 17 years, a damaged part changed with age, and it was estimated that it led to a crack. It was estimated for the leak of the plumbing that hydrogen produced with electrolytic protection caused hydrogen embrittlement cracking and hydrogen induced cracking. This paper reports the details of the investigations.