Tokyo / Istanbul – Japan’s Tokyo Electric Power Company Holdings Inc. (TEPCO) successfully restarted the No. 6 reactor at the Kashiwazaki-Kariwa nuclear power station in Niigata Prefecture on Monday, following a month-long suspension triggered by a control rod malfunction, local media reported.
The 1,360-megawatt boiling water reactor—part of the world’s largest nuclear power facility by total capacity (8.2 gigawatts across seven units)—was brought back online after TEPCO identified and addressed the cause of an alarm that sounded during control rod withdrawal on January 23, 2026. The reactor had briefly resumed operations in late January but was taken offline again within 24 hours due to the same issue.
TEPCO confirmed that the restart proceeded smoothly and that the company now plans to commence commercial operations on March 18, 2026, following additional equipment inspections and safety verifications to ensure full system reliability.
The Kashiwazaki-Kariwa plant, which uses the same boiling water reactor (BWR) design as the ill-fated Fukushima Daiichi facility, has remained largely idle since 2012 in the wake of the March 2011 Great East Japan Earthquake and tsunami that caused the Fukushima nuclear disaster. The prolonged hiatus reflected heightened safety concerns, regulatory scrutiny, and public opposition to restarting reactors of the same type involved in the 2011 meltdown.
Monday’s restart marks TEPCO’s first reactor reactivation at Kashiwazaki-Kariwa since the Fukushima accident more than 14 years ago. The company has invested heavily in post-Fukushima safety upgrades, including reinforced seawalls, improved emergency cooling systems, anti-terrorism measures, and enhanced seismic resistance to meet the stringent standards imposed by Japan’s Nuclear Regulation Authority (NRA).
The No. 6 unit is the only reactor at the site that has received full regulatory approval for restart. The remaining six reactors continue to face safety reviews, local government consent processes, and community consultations—steps required under Japan’s post-Fukushima regulatory framework.
The restart comes as Japan seeks to gradually increase its nuclear power generation to reduce reliance on imported fossil fuels, lower electricity costs, and meet ambitious carbon neutrality targets by 2050. Nuclear power currently accounts for a small fraction of the national energy mix, down sharply from pre-2011 levels, with most reactors still offline.
TEPCO and government officials have repeatedly stressed that safety remains the top priority. The company said extensive diagnostic tests and simulations confirmed that the January control rod issue posed no immediate risk and that similar malfunctions would now be prevented through updated procedures and monitoring.
Local residents and anti-nuclear groups have expressed continued concern, citing the plant’s location in a seismically active region and the historical trauma of Fukushima. Niigata Prefecture Governor Hideyo Hanazumi has maintained a cautious stance, requiring rigorous safety demonstrations and ongoing dialogue before supporting full operations.
The Kashiwazaki-Kariwa facility, if all seven units were operational, would represent approximately 10% of Japan’s total nuclear capacity. Its gradual return to service is seen as a key test of public and political acceptance of nuclear power revival in the post-Fukushima era.
TEPCO plans to maintain close communication with local communities, regulatory bodies, and the central government as the reactor progresses toward commercial operation in mid-March. Further inspections and trial runs will continue over the coming weeks to confirm long-term stability.
