The operator of the crippled Fukushima Daiichi nuclear plant said the release of treated radioactive water into the sea was automatically halted on Saturday after an alarm was triggered by low water flow in the pumping system.
Tokyo Electric Power Company Holdings Inc said the emergency shutoff valve on a pump that supplies seawater to dilute the treated water closed after water flow dropped following a momentary power outage affecting two power lines inside the plant. Thunderstorms were reported in the area at the time.
Radiation monitoring systems detected no abnormalities, and the water pump continued functioning, TEPCO said, adding that it will resume releasing treated water once it confirms the system is safe.
An alarm in the treated water discharge system sounded at 5:05 p.m. The same alarm was triggered Wednesday, also halting the water release. The release resumed the following day after the operator replaced a valve in the outlet of a tank that was suspected of triggering the alarm.
At the Fukushima plant, massive amounts of radioactive water have accumulated as melted nuclear fuel has been cooled since the March 2011 earthquake and tsunami disaster. The water is treated to remove most radionuclides except tritium before being diluted and released into the Pacific Ocean.
© KYODO
