Kansai Electric Power announced that a hole had been found in piping at Mihama Nuclear Power Station Unit 3. The hole is believed to have been caused by rainwater entering the pipe, and an investigation is under way following the shutdown.
Kansai Electric Power announced that a hole had developed in outdoor piping at Mihama Nuclear Power Station Unit 3 due to a water leak. A water leak from the piping was found at Unit 3 on the 17th, after which the reactor was manually shut down and an investigation began. Rainwater entering through a gap in the cover is currently cited as the cause, and it is presumed that rainwater passed through the gap.
The hole measured approximately 14 mm vertically and 4 mm horizontally. The pipe is located at a branch connected to the high-pressure turbine. The hole is presumed to have resulted from rainwater entering through a gap created when the cover was installed upside down. The investigation will also examine whether similar errors occurred at other nuclear power stations.
At Mihama Unit 3, a steam leak also occurred in May because of a hole in a cap. After the part was replaced, trial operation began on 12 September, but the unit was forced to shut down again. Kansai Electric had indicated that commercial operations were scheduled to resume on 9 October, but there is currently no prospect of a restart.
As a related topic, Kansai Electric is considering recurrence-prevention measures at Mihama Nuclear Power Station and has stated that it will also inspect and investigate its other nuclear power stations.