Japan restarts the world’s largest nuclear power plant

Japan has restarted a reactor at the world’s largest nuclear power plant, almost 15 years after a disaster at the Fukushima nuclear power plant forced the country to shut down all its nuclear reactors.

Reactor No. 6 at the Kashiwazaki-Kariwa plant northwest of Tokyo restarted Wednesday. It was postponed by a day due to an alarm failure and is expected to become commercially operational next month.

This is the final part of Japan’s nuclear power restart, which still has a long way to go. The seventh reactor is not expected to be operational again until 2030 and the remaining five can be decommissioned. As a result, the plant has much less capacity than it once had when all seven reactors were operational: 8.2 gigawatts.

Japan, which had always been heavily dependent on energy imports, was an early adopter of nuclear power. But these ambitions were thwarted in 2011 by what is now remembered as one of the worst nuclear disasters in history.

The meltdown of the Fukushima Daiichi reactors, caused by Japan’s most powerful earthquake ever, led to radioactive leakage. It traumatized local communities who were evacuated, and many have not returned despite official assurances that it was safe to do so.

Critics say the plant’s owner, Tokyo Electric Power Company, or Tepco, was unprepared and that their and the government’s response was not well coordinated. An independent government report called it a “man-made disaster” and blamed Tepco, although a court later acquitted three of their executives of negligence.

Yet fear and lack of confidence fueled public opposition to nuclear power, and Japan suspended its entire fleet of 54 reactors shortly after the Fukushima disaster.

The country has spent the past decade trying to shake up these power plants as it seeks to expand its source of clean energy to reach net-zero emissions by 2050.

Since 2015, the country has restarted 15 of the 33 operational reactors. The Kashiwazaki-Kariwa factory is the first of Tepco’s factories to restart.

Before 2011, nuclear power accounted for almost 30% of Japan’s electricity production and the country planned to increase that to 50% by 2030. Its energy plan unveiled a tamer goal last year: It wants nuclear power to meet 20% of its electricity needs by 2040.

Even that can be difficult.

Global momentum around nuclear energy is increasing, with the International Atomic Energy Agency estimating that the world’s nuclear energy capacity could more than double by 2050. In Japan, nuclear energy would account for only 8.5% of electricity in 2023.

Prime Minister Sanae Takaichi, who took office in October, has emphasized the importance of nuclear power to Japan’s energy self-sufficiency. Especially as it expects energy demand to rise due to data centers and semiconductor production.

Japan’s leaders and their energy companies have long pushed for nuclear power. They say it is more reliable than renewable energy such as solar and wind power, and better suited to Japan’s mountainous terrain. But critics say the emphasis on nuclear power has come at the expense of investing in renewables and cutting emissions.

As Japan tries to revive its nuclear energy ambitions, the cost of running the reactors has soared, partly due to new safety controls that require heavy investment from companies wanting to restart plants.

“Nuclear energy is becoming much more expensive than they ever thought,” says Koppenborg.

The government could subsidize the costs, or pass them on to consumers — both unpalatable options for Japan’s leaders, who have touted the affordability of nuclear power for decades. An expensive energy bill could also hurt the government at a time when households are protesting against rising costs.

“The government’s hands are tied when it comes to financially supporting nuclear power unless it is willing to back down on one of its key selling points,” says Koppenborg.

“I think [Japan’s nuclear power revival] is a drop in the bucket because it does not change the bigger picture of Japan’s nuclear power decline.”

In addition to the fear of another disaster like Fuksuhima, a series of scandals have also damaged public confidence.

The Kashiwazaki-Kariwa factory in particular was involved in some of these. In 2023, one of the employees lost a stack of documents after putting them on his car and forgetting them there before driving away. In November it was discovered that another had mishandled confidential documents.

A TEPCO spokesperson said the company reported the incidents to the Nuclear Regulation Authority (NRA), adding that it aimed to continue improving safety management.

These revelations are “a good sign” for transparency, says Koppenborg. But they also reveal that “Tepco is struggling to change its ways [and] the way it approaches safety”.

Earlier this month, the NRA suspended its investigation into restarting nuclear reactors at Chubu Electric’s Hamaoka plant in central Japan after it emerged that the company had manipulated earthquake data in its tests. The company apologized and said, “We will continue to respond honestly and to the extent possible to the NRA’s instructions and guidelines.”

Nei, the former nuclear official, said that while he was “surprised” by the Hamaoka scandal, he believed the severe punishment imposed on the operator should deter other companies from doing the same.

‘Electricity companies must recognize the importance of not doing that [falsify data]” he said, adding that authorities will “reject and punish” offending companies.

What happened in Fukushima turned Japanese public opinion against what was hailed as an affordable and sustainable form of energy.

Thousands of residents filed class action lawsuits against Tepco and the Japanese government, seeking compensation for property damage, emotional distress and health problems allegedly related to radiation exposure.

According to a Pew Research Center survey, in the weeks following the March 2011 disaster, 44% of Japanese believed that the use of nuclear energy should be reduced. That figure rose to 70% in 2012. But polls by Japanese business publication Nikkei in 2022 showed more than 50% of people supported nuclear power if safety was guaranteed.

But there is fear and mistrust. In 2023, the release of treated radioactive water from the Fukushima Daiichi nuclear power plant caused fear and anger both at home and abroad.

And many still remain against restarting nuclear power plants. In December, hundreds of protesters gathered outside the Niigata Prefectural Assembly, where Kashiwazaki-Kariwa is located, to express their security concerns.

“If something were to happen in the factory, we would be the ones to suffer the consequences,” one protester told Reuters.

Last week, ahead of the restart of Kashiwazaki-Kariwa, a small crowd gathered in front of Tepco’s headquarters to protest again.

After Fukushima, nuclear safety standards have been tightened. The NRA, a cabinet body created in 2012, now oversees the restart of the country’s nuclear power plants.

At Kashiwazaki-Kariwa, 15-meter-high sea walls have been built to protect against large tsunamis; watertight doors now protect critical equipment in the facility.

“Based on the new safety standards, [Japan’s nuclear plants] could even survive an earthquake and tsunami similar to the one in 2011,” Hisanori Nei, an adjunct professor at the National Graduate Institute for Policy Studies in Tokyo and a former senior nuclear safety official, told the BBC.

But what worries Dr. Florentine Koppenborg, a senior researcher at the Technical University of Munich, is: “They are preparing for the worst they have seen in the past, but not for what is to come.”

Some experts worry that this policy is not sufficiently planned to take into account rising sea levels due to climate change, or the megaquake that Japan expects once a century.

“If the past repeats itself, Japan is extremely well prepared,” says Koppenborg. “If something really unexpected happens and there’s a bigger-than-expected tsunami, we won’t know.”