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Nitrogen Supply Unit at Fukushima Daiichi Nuclear Power Station Resumes Operation After Malfunction

Tokyo Electric Power Company (TEPCO) reported on August 1 that a reactor nitrogen supply unit at the Fukushima Daiichi Nuclear Power Station malfunctioned that day, but was subsequently repaired and resumed gas supply. The company stated that during the malfunction, no significant fluctuations were observed in hydrogen concentrations inside the reactors of Units 1 to 3 or in surrounding radiation monitoring data, and no risk of hydrogen explosion was confirmed. The reactor containments and pressure vessels of Units 1 to 3 at the Fukushima Daiichi Nuclear Power Station require continuous nitrogen injection to suppress hydrogen accumulation resulting from radiolysis of water. If hydrogen concentrations exceed a certain level, the risk of hydrogen explosion may increase. According to TEPCO, at 11:14 a.m. on August 1, a worker...

2026-08-03

Third fuel debris retrieval test at Fukushima Daiichi Unit 2 postponed due to robotic arm malfunction

The robot used by Tokyo Electric Power Company (TEPCO) for the third experimental fuel debris retrieval at Fukushima Daiichi Nuclear Power Station Unit 2 malfunctioned during an on-site operational test, forcing the cancellation of the plan originally scheduled to start after July 2026 if all went well. The company stated it will reassess the relevant procedures. The malfunction occurred in part of the large robotic arm equipment used to collect fuel debris. During an operational test in the reactor building of Unit 2, TEPCO found an abnormality in one of the motors driving the robotic arm, causing the brake to fail to release and the arm to be unable to extend. The company is currently studying the replacement of the faulty motor. The third experimental retrieval plan was to use a large robotic arm...

2026-07-31

TEPCO says cooling interruption of spent fuel pool at Fukushima Daini Unit 1 due to human error

Tokyo Electric Power Company (TEPCO) announced on July 29 that the event in April 2026, where the spent fuel pool cooling system at Unit 1 of the Fukushima Daini Nuclear Power Plant was shut down for approximately 32 hours, was determined to be caused by human error. At the time of the incident, the plant was in the decommissioning phase. On April 5, a fault alarm was triggered by the cooling water circulation pump of Unit 1 at Fukushima Daini. After on-site personnel confirmed smoke from the equipment, the pump was stopped, resulting in an interruption of the spent fuel pool cooling system for about 32 hours. TEPCO previously stated that the cause was damage to the cable connecting the pump motor. According to TEPCO's latest explanation, the cable melting may be related to the installation method when the cable was replaced in 2012...

2026-07-30