Plant operator Tokyo Electric Power Company Holdings (TEPCO) said the alarm sounded at approximately 5:05 p.m. local time on Saturday when a drop in water flow was detected in the pumping system responsible for the discharge operation, News.az reports.
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Following an inspection, the company reported that no equipment failure had been found. TEPCO said a brief simultaneous outage affecting two power transmission circuits caused seawater transfer pump flow rates to decrease, triggering the automatic closure of an emergency shutoff valve and halting the wastewater release process.
The utility said the discharge operation will resume once the necessary preparations have been completed.
Second Fukushima Wastewater Discharge Interruption in One Week
The latest suspension marks the second disruption to Fukushima wastewater discharge operations in recent days. A previous alarm on Wednesday forced a temporary halt after a suspected valve malfunction was detected in a storage tank. The release resumed the following day after the affected valve was replaced.
TEPCO launched the 20th round of treated wastewater discharge from the Fukushima plant on June 1 as part of its long-term decommissioning and water management program.
Thousands of Tonnes of Treated Wastewater Scheduled for Release
Under the company’s current plan, the latest discharge cycle is expected to continue through June 19. Approximately 7,800 tonnes of treated wastewater are scheduled to be released into the ocean during this phase.
According to TEPCO, the discharged water contains around 1.3 trillion becquerels of tritium, a radioactive isotope that remains in the treated water after processing.
The wastewater release program has remained a subject of international debate since Japan began ocean discharges in 2023, with neighboring countries and environmental groups continuing to monitor the process closely.


