TOKYO / NIIGATA — Fifteen years after the devastating Fukushima Daiichi nuclear disaster, Japan is moving to restart the world’s largest nuclear power plant, a move that underscores a dramatic shift in its energy policy — and rekindles longstanding debates about safety, community consent, and climate goals. The Kashiwazaki‑Kariwa Nuclear Power Station, operated by Tokyo Electric Power Company (TEPCO), has been dormant since the 2011 catastrophe but is now poised to return to service amid pressing concerns over energy security and decarbonisation.
A Milestone in Japan’s Long Nuclear Odyssey
Located in Niigata Prefecture, about 220 km northwest of Tokyo, the Kashiwazaki‑Kariwa plant occupies over 4 km² on the Sea of Japan coast and has the capacity to generate about 8.2 gigawatts of electricity when all seven reactors operate — enough to power millions of households.
Following the 9.0‑magnitude Tōhoku earthquake and tsunami, which triggered the Fukushima disaster in March 2011 and led to core meltdowns at multiple reactors, Japan shut down almost its entire nuclear fleet as part of a sweeping safety overhaul. More than a decade later, the restart of Kashiwazaki‑Kariwa’s Reactor No. 6 — with plans to go online in early 2026 after regulatory and local approvals — marks a symbolic and practical return to nuclear power.
This restart is the first for a TEPCO‑operated plant since Fukushima, as the company works to rebuild public trust and demonstrate enhanced safety.
Why Japan Is Returning to Nuclear Power
After Fukushima, nuclear energy’s contribution to Japan’s electricity mix dropped from about 30 percent before 2011 to nearly zero. Since then, a gradual restart process has brought some reactors back online, but not enough to restore nuclear’s previous share.
Several factors are driving Japan’s renewed embrace of nuclear power:
- Energy Security: Japan imports more than 90 percent of its energy, relying heavily on liquefied natural gas, coal and oil. Restarting nuclear plants reduces this dependency and hedges against volatile global fuel markets.
- Economic Considerations: Imported fuels are costly; nuclear power can help stabilise electricity prices for households and industry over the long term.
- Climate Goals: Nuclear generation produces minimal direct carbon emissions, a key consideration as Tokyo pursues its commitments to reduce greenhouse gases and transition to a low‑carbon energy mix.
- Rising Demand: Even with a shrinking population, Japan anticipates growth in electricity use from energy‑intensive sectors such as data centres, making reliable baseload power attractive.
Prime Minister Sanae Takaichi has publicly backed the restart strategy as part of broader efforts to secure stable energy sources and support national goals.
Technical Upgrades and Safety Improvements
Japan’s nuclear industry has been reshaped by strict lessons from Fukushima. Safety regulatory reforms since 2011 require robust protections against earthquakes and tsunamis, comprehensive emergency systems, and improved disaster preparedness.
At Kashiwazaki‑Kariwa, TEPCO has undertaken extensive safety upgrades, including enhanced seawalls, watertight doors, mobile diesel generators, and updated cooling systems designed to withstand severe events. Ground vibration and seismic reinforcement work has also been conducted to meet current Nuclear Regulation Authority (NRA) standards.
Despite these efforts, recent pre‑start commissioning tests detected an alarm malfunction in the reactor’s safety systems, delaying the planned restart as technicians address the issue to ensure compliance with operational safety benchmarks.
Community Opposition and Local Consent
The restart has sparked significant controversy, particularly among residents living within the 30 km evacuation zone who remain wary of nuclear risk. Public surveys show strong concerns about the potential for another accident similar to Fukushima.
Anti‑nuclear campaigners have criticised both TEPCO and political leaders, accusing them of prioritising energy strategy over local safety preferences. Some locals have pushed for referendums on the plant’s future, but these efforts were not authorised, leaving opponents feeling disenfranchised.
Demonstrations have taken place in Niigata and other cities, with banners warning against nuclear restarts and highlighting the psychological legacy of Fukushima for affected families and communities.
Japan’s Nuclear Fleet Since Fukushima
Kashiwazaki‑Kariwa is not the only plant returning to operation. Domestic utilities have restarted 14 of Japan’s 33 operable reactors since 2015, following comprehensive NRA safety reviews. Reactors such as Sendai Unit 2 and Shimane Unit 2 have resumed power generation, contributing to a growing nuclear renaissance in the country’s energy landscape.
Nonetheless, the pace has been slow. Many units remain offline due to regulatory hurdles, seismic concerns, or local resistance. The challenges illustrate both the technical complexity and social sensitivity of nuclear policy in post‑Fukushima Japan.
Broader Implications for Japan and Beyond
Japan’s decision to restart its largest nuclear facility sends a signal not only about energy policy but about national resilience and priorities in a changing global environment. The restart could help reduce carbon emissions and improve energy independence, but it also highlights the tensions between economic imperatives and public apprehension about nuclear technology.
Analysts note that while Japan’s path diverges from earlier anti‑nuclear sentiment, it reflects broader global trends in which countries reassess nuclear power as part of climate and energy strategies. However, the Japanese experience remains unique due to the scale and severity of the Fukushima disaster and its deep imprint on public consciousness.
What Comes Next
Kashiwazaki‑Kariwa’s restart — potentially scheduled for January 2026 pending final approvals and test completions — will mark a major milestone in Japan’s long and cautious return to nuclear power. If successful, Reactor No. 6 could boost electricity supply to the Tokyo metropolitan area by about 2 percent, reducing reliance on imported fuels and contributing to emissions goals.
Yet public debate is likely to continue, with safety, community consent, and disaster preparedness at the centre of discussions about the future of nuclear energy in Japan. How the government and TEPCO address these concerns may determine not only the success of this restart, but the broader role nuclear power will play in the nation’s energy mix in the decades ahead.
