Japan pauses restart of world’s largest nuclear power plant one day after it went online

Japan suspended the restart of a reactor at the Kashiwazaki-Kariwa nuclear plant in Niigata province, the world's largest, just hours after operations began on Thursday. The plant, operated by Tokyo Electric Power Company (Tepco), had been closed since the 2011 Fukushima disaster but recently received regulatory approval to restart. An alarm from the monitoring system triggered the suspension during the reactor start-up procedures. Tepco is investigating the malfunctioning electrical equipment and decided to reinsert the control rods to halt the chain reaction in a planned manner. The operator assures that the reactor remains stable and there is no radioactive impact outside the plant.

Japan suspended operations at the Kashiwazaki-Kariwa nuclear plant, the world's largest, hours after restarting reactor number six on Wednesday. The restart, the first since the 2011 Fukushima disaster, was delayed due to an alarm malfunction. Another alarm sounded during start-up procedures on Thursday, prompting the suspension, although the reactor remained stable with no external radioactive impact. Tepco, the plant's operator, is investigating the cause of the incident, with no timeline for resuming operations. The restart faced local opposition due to safety concerns stemming from the Fukushima meltdown, which led to the shutdown of all of Japan's reactors. Japan aims to revive nuclear power to achieve net-zero emissions by 2050, having restarted 15 reactors since 2015.

After a 15-year shutdown following the Fukushima disaster, Japan is restarting the Kashiwazaki-Kariwa nuclear power plant in Niigata province, the world's largest. Operated by TEPCO, the plant's initial restart involves one of its seven reactors, with the potential to generate 8.2 gigawatts when fully operational. The move aims to bolster Japan's energy security and reduce dependence on imported fossil fuels, particularly after setbacks in offshore wind development. Kashiwazaki-Kariwa is the 15th plant to be reactivated out of 33 operable in Japan, with the government also pushing for the construction of new reactors. Despite safety upgrades, including a tsunami wall, concerns remain, highlighted by a petition citing seismic activity risks.

Japan's Tokyo Electric Power Company (Tepco) suspended the restart of the Kashiwazaki-Kariwa nuclear power plant in Niigata province, the world's largest, just one day after operations began on Wednesday. The plant, offline since the 2011 Fukushima disaster, halted operations due to an alarm from the monitoring system during reactor startup. Tepco officials stated they do not know how long the problem will take to resolve and are focusing on identifying the cause. The reactor is currently stable with no external radioactive impact. Japan aims to revive nuclear energy to reduce reliance on fossil fuels and meet energy needs, despite local opposition citing seismic concerns. This is the first Tepco-run unit to restart since 2011.

A reactor at the Kashiwazaki-Kariwa nuclear plant in Japan, the world's largest, was suspended a day after its restart on Wednesday, January 21, 2026. The operator, TEPCO, which also manages the Fukushima plant, halted the process due to a malfunction related to the control rods, which are crucial for reactor startup and shutdown. The restart, initially scheduled for Tuesday, had already been delayed due to a prior technical issue with the rods. TEPCO stated that the reactor remains stable, there is no radioactive impact outside the plant, and they are investigating the situation. The duration of the shutdown is currently unknown.

Tokyo Electric Power Company (Tepco) restarted the No. 6 reactor at the Kashiwazaki-Kariwa nuclear plant in Niigata Prefecture on Wednesday, marking its first reactor restart since the 2011 Fukushima disaster. This is the 15th reactor in Japan to resume operation under stricter safety standards implemented after Fukushima. The restart is a significant step for the Japanese government, which advocates for nuclear power due to the country's limited resources. The reactor reached criticality at 8:28 PM local time, and Tepco plans to begin transmitting power to Tokyo on a trial basis next Tuesday, with commercial operation scheduled for February 26. The restart is under close scrutiny due to public safety concerns following the Fukushima incident.