Several damaged pipes carrying sea water were found at the No. 5 reactor of the Hamaoka nuclear power plant in Omaezaki, Shizuoka Prefecture, plant operator Chubu Electric Power Co. said May 20.
Several damaged pipes carrying sea water were found at the No. 5 reactor of the Hamaoka nuclear power plant in Omaezaki, Shizuoka Prefecture, plant operator Chubu Electric Power Co. said May 20.
Damage was found to small pipes running inside the condenser of the boiling water reactor, which turns steam into water after it has been used to power the turbine. At least 20 of the approximately 21,000 titanium pipes, which are 0.5 millimeters thick and have a diameter of 3 centimeters, had cracks or holes in them.
The damage appears to have been caused by the end cap of a nearby pipe, which came off and was found on the ground. It possibly became dislodged due to worn welds, but the details are yet to be confirmed, according to a Chubu Electric official.
The official also said that the end cap had been checked in a routine inspection that ran from March last year through February this year, but the inspection was only visual.
Shutdown operations started at the No. 5 reactor on May 14 on the order of Prime Minister Naoto Kan. At that time, water was being pumped into the pipe found to be missing an end cap.
Chubu Electric says that no radioactive substances were leaked outside in this incident.