World's biggest nuclear power station that's 8 times bigger than earth's smallest country

plays a big role in supplying to millions of people around the world. As of May 2025, there were 441 reactors operating across more than 30 countries, according to . The has the most, with 94 units.

But the largest nuclear plant on Earth isn't in the US. It's in , and it's absolutely massive. The Kashiwazaki-Kariwa Nuclear Power Plant, located in Niigata Prefecture on the coast of the , is the biggest nuclear power station in the world by capacity, according to . It has seven reactors and can produce 7,965 megawatts of , nearly eight gigawatts.

The site spans 4.2 square kilometres, or roughly 1,000 acres, making it more than eight times larger than Vatican City, which covers just 121 acres.

The facility is operated by Tokyo Electric Power Company (TEPCO) and plays an important role in Japan's energy system.

It houses the world's first Advanced Boiling Water Reactor (ABWR), and while construction began in the 1980s, the last of its seven units, Unit 7, was completed in 1997.

The plant was affected by the 2007 Chetsu offshore earthquake, which caused it to shut down for almost two years.

Although it was not directly impacted by the 2011 Fukushima disaster, all of its reactors were later shut down for safety upgrades, according to TEPCO.

Units 6 and 7 were approved for restart by Japan's Nuclear Regulation Authority (NRA) in 2017, but a series of delays followed, including security breaches and counter-terrorism concerns.

The NRA only granted approval to reload fuel at the plant in December 2023, citing improvements to its safety management system.

In early 2025, reported that hoped to restart a reactor during the 2025 fiscal year.

The restart was expected to boost the company's earnings by around ¥100 billion (roughly £520 million) a year.

The mayor of Kashiwazaki, Masahiro Sakurai, also indicated support for restarting reactors 6 and 7, saying: "We have reached a stage where we can accept a possible request for reactivation," according to .

However, TEPCO later announced that it had pushed back the completion of counter-terrorism measures at Unit 7 from March 2025 to August 2029, meaning it will miss the October 2025 regulatory deadline.

As a result, the reactor may be forced to shut for an extended period, even if it restarts beforehand.

reported that unit 6's target date has also been delayed from September 2026 to September 2031. Both reactors remain offline and must still secure local government approval.

The governor of Niigata, Hideyo Hanazumi, has said safety concerns remain a top priority and he will continue to prioritise the views of local residents.

TEPCO has said that restarting one reactor could boost profits by ¥100 billion (£514million) a year and cut carbon emissions by 3.3 million tonnes annually.