Japan’s nuclear odyssey comes full circle 15 years after Fukushima with restart of world’s largest plant

KASHIWAZAKI (Niigata) – Come 2026, Japan will fire up the world’s largest nuclear power plant again in a powerful signal that the nation is turning a page on the

2011 Fukushima disaster.

The Kashiwazaki-Kariwa Nuclear Power Plant, known colloquially as KK, shares the same operator as the crippled Fukushima Daiichi plant – Tokyo Electric Power Company (TEPCO).

It is certified by the Guinness Book of World Records as the world’s largest plant by net output at 8.2GW, which is enough to power more than 13 million homes, and its restart will be the first time TEPCO is powering up a nuclear plant since the disaster.

KK, which began operations in 1985, has seven reactor units across a 4.2 sq km area along the coast of Niigata prefecture in eastern Japan. While it previously supplied electricity mainly to the Tokyo Metropolitan Region, the plant has been sitting idle.

On March 11, 2011, a 9-magnitude earthquake unleashed tsunami waves that triggered a triple meltdown at the Fukushima Daiichi plant in north-eastern Japan, in one of the world’s worst nuclear accidents.

In the aftermath, Japan pulled the plug on nuclear power, mothballing all 54 of its reactors. It drew up stricter operation safety guidelines and established a new Nuclear Regulation Authority (NRA) to assess and enforce these standards.

The Straits Times was recently granted a visit to KK, where TEPCO is preparing for the restart of Units 6 and 7, each with a 1.35GW capacity.

Post-Fukushima, global anxieties grew over nuclear power as a source of clean energy to combat climate change. But the passage of time, coupled with the urgency to secure clean alternatives to fossil energy, has led to a pendulum swing towards nuclear power.

But nowhere is this shift more evident than in Japan, where public sentiment has oscillated from vehement opposition to pragmatic acceptance over 15 years.

A survey by Jiji Press Agency released on Dec 11 showed 44.7 per cent of respondents in favour of bringing nuclear plants back online, against 26.1 per cent opposed and another 29.2 per cent with no opinion. A poll by the same agency in 2011 showed 64.7 per cent in favour of total abolition of nuclear power.

Economy Minister Ryosei Akazawa said in November: “KK’s restart is extremely important from the perspectives of power supply and demand, curbing electricity rates, and securing decarbonised power sources.”

This journey, however, has been a roller-coaster ride.

The NRA approved KK’s enhanced safety measures at Units 6 and 7 in December 2017, only to effectively rescind this approval in 2021 after security breaches were found, including the fraudulent use of employee ID cards and malfunctioning intrusion detectors.

The regulators

lifted this operational ban

in December 2023.

But KK remained idle throughout, as NRA approval is not enough for nuclear plant operations. “Local consent” is necessary, with the prefectural authorities having the final say.

On Nov 21, Niigata Governor Hideyo Hanazumi finally

gave his nod

, with the Niigata Prefectural Assembly due to

approve the decision

in the ongoing session ending on Dec 22.

Japanese media on Dec 17 cited sources saying that, if all goes well, TEPCO would bring KK’s Unit 6 back online around Jan 20, 2026. The reactor’s output will gradually be increased during this “soft launch” phase before commercial operations resume by March.

After this, Unit 7 will be restarted by 2029, pending the construction of an anti-terrorism facility.

“We cannot keep the plant closed without any justification when it meets national regulatory standards,” Mr Hanazumi said, noting that KK’s restart was critical to “address the fragile power supply base in eastern Japan”.

Watershed decision

Of the 54 nuclear reactors, 33 were deemed operable post-Fukushima, with the rest slated for decommissioning. Yet only 14 have been brought back online, all but one in western Japan.

That, essentially, is a reflection of how public resistance against nuclear power was weaker farther from Fukushima.

As a result, electricity bills are generally cheaper for households in Osaka than in Tokyo, given that Japan’s power grids are effectively managed in isolation across regions, in large part because of the division of Japan into 10 service areas each with its own utility, with limited capacity for power-sharing.

Tokyo has suffered power shortages in recent years, and resuming operations at KK would go a long way towards resolving these grid vulnerabilities.

Mr Hanazumi, a two-term governor first elected in 2018 with the backing of Japan’s ruling pro-nuclear Liberal Democratic Party (LDP), likely could not postpone any longer the inevitable amid shifting national winds.

While he has never outrightly expressed any opinion for or against nuclear energy, he considers it important to err on the side of caution. This stance meant sitting on a decision that, in other regions, is usually made within months of the NRA’s approval.

But Mr Hanazumi had exhausted the tools in his kit of delay, from “opinion exchange sessions” with mayors across Niigata’s 30 municipalities to “public hearing sessions”, and finally, a survey that showed more people in support of the restart than against.

Across Niigata, a prefecture of 2.07 million people, 50 per cent were in support and 47 per cent were against KK’s restart. Support was far more pronounced in the two municipalities hosting KK – Kashiwazaki and Kariwa – where six in 10 were in favour.

Further, under the revised Strategic Energy Plan in February, the LDP-led government emphasised the “

maximum utilisation

” of nuclear energy to meet growing electricity demand given the exponential growth of data centres, as a net-zero carbon emissions target looms in 2050.

Japan’s energy self-sufficiency currently stands at 15.2 per cent. Nuclear energy accounted for 10.5 per cent of the country’s energy mix as at March 2025, and Japan aims to increase this to 20 per cent by March 2041.

Against this backdrop, Mr Hanazumi’s consent for KK after holding off for years is seen as a watershed moment that will accelerate momentum for the revival of nuclear power use in Japan.

On Dec 10, Hokkaido Governor Naomichi Suzuki

approved the restart of Unit 3 at Tomari Nuclear Plant

after his apparent initial indifference – local stakeholders told ST in October of “political considerations” behind the difficulty for nuclear power to form a bigger part of Hokkaido’s energy mix. The reactor is scheduled to restart in 2027.

Across Japan, there is also a renewed push towards building new nuclear plants or expanding existing ones. Geological surveys are being conducted for a

new reactor at the Mihama plant

in Fukui prefecture.

Nuclear politics

Kashiwazaki, now a sleepy seaside city of 75,000 people, has long been the epicentre of Japan’s energy industry. The Nihon Shoki, a historical record published in 720, records crude oil from the city being offered to Emperor Tenji in 668.

More recently, Kashiwazaki was also a key location for Nippon Oil, the predecessor of Japanese petroleum giant ENEOS, after its founding in 1888.

Kashiwazaki Mayor Masahiro Sakurai wants to establish his home town as a “decarbonised energy hub” with nuclear power as a key plank alongside other renewable energy forms such as solar and wind.

The three-term mayor, first elected in 2016, was candid about his frustrations over how long Mr Hanazumi took to approve KK’s restart.

He told ST that he felt the governor’s exploitation of “local consent” regulations “defies logic” and could set a bad precedent – a sentiment he has directly expressed to the national government.

Among his criticisms was the insistence on canvassing opinions from all 30 municipalities of Niigata prefecture.

Mr Sakurai notes the farthest point within Niigata from KK was about 180km away, alluding to politicking when the maximum evacuation radius for the Fukushima disaster was up to 50km from the plant.

Rather than a prefecture-wide approach to “local consent”, he said a proximity-based policy would make more sense, with the opinions of those living closer to a nuclear plant carrying more weight.

As the crow flies, KK is nearer the popular winter ski resort Hakuba in Nagano prefecture (100km), and parts of neighbouring Gunma and Toyama prefectures, than to the border town of Murakami in Niigata.

“Now it is as if radioactivity stops at prefectural borders,” he added, noting that the farther away people live from a nuclear plant, the less invested they would be in the issue.

Fukushima lessons

KK is all ready to restart – TEPCO loaded nuclear fuel rods into its Unit 6 in June in preparation for it.

Risk communicator Takeshi Dozono told ST: “Once we get the green light, KK can resume operations almost immediately. Since the plant has been in shutdown for quite some time, we are now double-checking the integrity of each piece of equipment to ensure they are functioning properly.”

Units 6 and 7, which began operations in 1996 and 1997, are the newest of KK’s seven reactors. They are advanced boiling water reactors (ABWRs), an improved design over older BWR models used in the other five units.

TEPCO will likely decommission Units 1 and 2, with the fate of the other three units up in the air. If the decision is to reopen them, additional investments will be necessary to meet NRA’s guidelines.

The company has been focusing its efforts on Units 6 and 7, investing 1.2 trillion yen (S$9.8 billion) in upgrades to disaster-proof the plant.

This includes a 15m-tall seawall, far higher than worst-case scenario forecasts of tsunami waves of up to 6.8m along Niigata’s coast.

Mr Dozono pointed to many lessons learnt from Fukushima.

Normally, an earthquake would trigger an emergency response that automatically shuts down the reactors, with water circulated to keep the fuel rods cool.

But in 2011, the tsunami waves knocked out emergency generators essential for running the cooling systems. This complete loss of power led to the overheating of fuel rods, causing hydrogen explosions that spewed radiation into the atmosphere.

TEPCO has a fleet of 20 backup generator vehicles and 42 truck-mounted fire pumps across KK, and has built a 20,000 cubic m reservoir on-site with water that can be pumped into the reactors if power gets cut off.

Further, it has built secondary barricades such as heavy watertight doors to keep seawater from entering the reactor buildings and knocking out essential equipment. Firebreaks have been set up to ensure that any fires do not spread.

It has also installed filter vents that remove radioactive materials, as well as catalytic converters that can combine hydrogen and oxygen to create water vapour. This prevents the excessive build-up of hydrogen to dangerous levels, Mr Dozono said.

From hubris to humility

But KK’s restart is not just a simple question of flipping a switch.

TEPCO continues to suffer from a deep deficit in trust and goodwill from the public, owing to the Fukushima disaster and subsequent security lapses that have cast a long shadow over its corporate culture.

Recognising the local impact, TEPCO is pledging a 100 billion yen fund over 10 years to support job creation, new industries and decarbonisation projects in Niigata prefecture.

It is also devoting itself to ground-up efforts. Mr Kazushi Yamada leads the so-called Regional Coexistence Department that TEPCO set up in 2015. It has engaged in dialogue with over 40,000 residents in Niigata so far.

“We communicate with everyone, whether they’re for or against, without discrimination,” he told ST. “It’s important to listen carefully to even harsh ideological messages.”

And there is no lack of deep-seated local opposition.

Cafe owner Yumiko Abe, 63, and homemaker Eiko Takeuchi, 56, contested the Kashiwazaki mayoral polls on an anti-nuclear platform in 2024 and 2016 respectively. They cited a litany of reasons for their antipathy towards nuclear power, with safety fears just the tip of the iceberg.

Ms Takeuchi believes the nuclear industry is driven by vested interests, and fears that Kashiwazaki has become so dependent on KK for its economy that it is unable to innovate.

Ms Abe, meanwhile, pointed to how nuclear plants generate waste that remains acutely hazardous for the first 600 years and would take 100,000 years to decay, arguing that the energy form “cannot be considered clean”.

Yet Dr Dale Klein, former chairman of the US Nuclear Regulatory Commission and a member of TEPCO’s independent advisory committee, told ST that nuclear waste “was a political problem, not a technical problem”. 

Countries worldwide have found solutions, with Japan reprocessing its low-level nuclear waste to recover uranium and plutonium that are used to create new fuel, and high-level radioactive waste stored in shielded canisters that are buried deep underground.

Mr Yasuyoshi Kuwabara, 77, who chairs the Arahama 21 Forum in support of KK’s restart, argued that rationality should prevail over paranoia.

“What matters is that TEPCO is taking thorough steps to ensure safety. Accidents can happen anywhere, including on the road. Does that stop people from going outside?” he said.

Ultimately, at the heart of KK’s journey towards its restart are employees like Mr Masaoki Takano, 34, who joined TEPCO as an electrician in 2010.

A native of Kashiwazaki, he confessed to having been disillusioned – even ashamed – of being associated with TEPCO. 

“When I joined, there was very little awareness of the dangers of nuclear power, and I believed that an accident would never occur. Then Fukushima happened, and I realised nuclear power can be a scary and dangerous thing,” he told ST.

His journey reflects a transformation from hubris to humility, one that TEPCO must prove to its sceptics it has undergone.

Now a father of three, he wants his children to grow up in a greener world and, despite the dangers that nuclear power poses, he sees it as part of that world.

He said: “With challenges like global warming, nuclear energy is an important clean energy source. I’m working hard every day to get the plant back up and running.”