Pipe rupture incident of Hamaoka Nuclear Power Station Unit-1

At the Hamaoka Nuclear Power Station Unit-1 (540 MWe of electric output; BWR-4 type) of the Chubu Electric Power Co., Ltd., an incident of pipe rupture of residual heat removal system on steam condenser system occurred on November, 2001. This incident gave no effects on outer parts of the station, because safety system apparatuses in the station worked adequately from a standpoint of accidental phenomenon. On the other hand, on its forming processes, as it is no similar case at the nuclear power stations in and out of Japan, to securely carry out countermeasures for preventing a recurrence of the incidence, its cause was striven to elucidate thoroughly. This paper was introduced about contents and results on site surveys, and surveys such as tests, analysis, and so on performed for about a half year after the incident, for preventing a recurrence of similar incidents. (G.K.)