Tokyo Electric Power Company Holdings (TEPCO) has postponed the highly anticipated restart of the No. 6 reactor at its Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture after an equipment alarm malfunction surfaced during pre-start testing, officials announced on Monday. The delay comes as Japan continues to wrestle with the legacy of the 2011 Fukushima Daiichi disaster and seeks to balance energy security with public safety fears.
The Kashiwazaki-Kariwa facility, located roughly 220 km northwest of Tokyo on the Sea of Japan coast, is the largest nuclear power station in the world by capacity, with seven reactors capable of producing about 8.2 gigawatts of electricity. All units have been offline since the aftermath of the Fukushima meltdown, when a massive earthquake and tsunami triggered core failures that forced widespread evacuations and deep public distrust of nuclear energy.
TEPCO had planned to bring the No. 6 reactor back online on Tuesday in what would have been its first restart of one of the company’s reactors since the Fukushima catastrophe. However, during a weekend test of the control rod suppression system — a critical safety feature designed to halt fission reactions — an alarm failed to activate as expected. The company discovered the issue during a routine test and corrected a settings error, but determined that additional checks were necessary before restarting the reactor. TEPCO has said it will consult with Japan’s nuclear regulator to determine a new timeline, which industry sources suggest may be only days later, with commercial operations now eyed for late February.
The delay underscores persistent safety concerns over Japan’s nuclear revival strategy. While the government and TEPCO argue that restarting nuclear plants is critical for reducing dependence on imported fossil fuels, cutting carbon emissions and strengthening energy security, many local residents remain deeply skeptical. Critics point to the Fukushima disaster’s enduring human and environmental toll and question whether Japan’s plants are adequately prepared to withstand earthquakes, tsunamis and other natural hazards. Polls conducted in Niigata and surrounding areas have shown significant opposition to the restart plans, with residents warning that current evacuation plans are inadequate, especially during harsh winter conditions when road blockages could imperil vulnerable populations.
In an effort to win community trust, TEPCO has pledged to invest heavily in safety upgrades at the plant, including improved tsunami defenses, watertight doors, enhanced emergency power generators and filtered systems to limit the release of radioactive materials. The company has also proposed investing roughly ¥100 billion in the region over the next decade to support local development and infrastructure as part of its broader engagement strategy.
Despite these measures, opposition remains vocal. Local leaders and residents have criticized what they see as insufficient public consultation and have repeatedly called for greater transparency in safety planning. Many argue that human safety and effective disaster preparedness should take precedence over national energy policy goals and corporate interests. Surveys indicate that a majority of people living within the potential evacuation zone around Kashiwazaki-Kariwa fear a repeat of Fukushima-style calamity, highlighting the emotional and psychological legacy of the 2011 disaster that continues to shape public opinion.
The postponement also arrives against a backdrop of broader challenges for Japan’s nuclear sector. The country’s Nuclear Regulation Authority has recently halted reviews of other reactor restarts — including at the Hamaoka plant — after revelations of falsified seismic safety data by another utility, prompting resignations and intensified scrutiny of safety culture across the industry.
As Japan strives to meet its energy and climate objectives, the fate of Kashiwazaki-Kariwa and other idle nuclear plants will be watched closely both domestically and internationally, with the coming weeks likely to shed further light on how Tokyo navigates the complex intersection of technology, safety and public trust.
