nuclear-news

Nuclear power’s role in Japan is fading. The myths of reactor safety and energy needs can’t change that reality.

By Tadahiro Katsuta , Bulletin of Atomic Scientists 11th Dec 2025

On November 24, the Niigata Prefecture approved the partial restart of the seven-unit Kashiwazaki-Kariwa Nuclear Power Plant—the world’s largest, with a 7,965-megawatt-electric capacity—the first time it would be operated since the 2011 Fukushima Daiichi accident. The decision follows a series of efforts by the Japanese government to revive its nuclear industry since the Fukushima disaster led to the temporary shutdown of all its reactors.

In February, the Japanese government unveiled the country’s latest revised strategic energy plan with one significant shift: It no longer includes the commitment to “reduce dependence on nuclear power as much as possible.” Since the 2011 Fukushima accident, this objective has been reaffirmed in all three revisions preceding the 2022 plan. Its removal marks a clear departure from the government’s previously cautious stance on Japan’s nuclear policy.

Decommissioning work of the Fukushima Daiichi plant is still falling behind schedule, and there are no prospects for fully lifting the evacuation orders in the Fukushima Prefecture. This uncertainty surrounding post-accident Fukushima casts doubt on the government’s ability to manage another nuclear crisis. Meanwhile, the government’s plan actively promotes the “effective use” of plutonium through the reprocessing of spent nuclear fuel and the “usefulness” of nuclear power as a decarbonized power source in its newest plan.

The Japanese government had consistently maintained a strong policy of promoting nuclear power since the initial planning stage in the 1950s until the Fukushima accident. Its current position, therefore, comes as little surprise. But in the nearly 15 years since the accident, Japan’s energy structure and society have changed—and all evidence shows that nuclear power cannot simply be switched on again, despite what the government claims.

Displaced by renewable energy. As a result of new safety regulations that the Nuclear Regulation Authority (NRA) established in 2012, nuclear power plants with inadequate accident prevention measures are still unable to operate.

Japan used to operate 54 commercial nuclear power plants before the Fukushima accident, but so far only 14 have obtained operating permits and resumed operations. This translated into nuclear power’s share of electricity supply dropping to just over 5 percent from the 29 percent before the accident. The government is seeking a 20-percent share by fiscal 2040 but has not presented any specific measures to achieve this goal.

Meanwhile, renewable energy has increased rapidly since the Fukushima accident, partially filling the vacuum of the shutdown reactors. Renewable energy now supplies 226 terawatt-hours of electricity—more than twice the 84 terawatt-hours supplied by nuclear power. And renewables will continue to dominate the electricity market with a target share of 40 to 50 percent by 2040, also more than double that of nuclear power……………..

While nuclear power lacks competitiveness in the electricity market, Japan’s electricity demand has already plateaued. Demand has decreased by more than 10 percent since 2010,^[2] according to the latest figures. The government insists that electricity consumption will increase sharply over the next 10 years due to the growing demand in data centers and semiconductor factories. However, even if this happens, it will still result in a lower electricity demand compared to 2010.

Unlike France, Japan does not allow output adjustments for nuclear power generation, and being an island nation, it cannot export electricity overseas. Moreover, with a slowing economy and a shrinking population, electricity demand has already peaked. In a market that seeks to maximize profits by anticipating short-term electricity demand and avoiding excess power generation, nuclear power is not an attractive option.

Does Japan need MOX fuel?

……………………………………………..Power companies and the government have not disclosed what the cost will be for Japan of manufacturing this MOX fuel abroad and then importing it. But trade statistics indicate that the MOX fuel commissioned at a French reprocessing plant cost approximately $11,000 per kilogram of heavy metal (primarily plutonium and uranium), while uranium fuel imported from the United States cost approximately $1,000 per kilogram of heavy metal. In other words, MOX fuel is more than 10 times as expensive as imported non-reprocessed reactor fuel.^[3]………………….

Does nuclear power mean fewer CO2 emissions?

……………………………………………………………………………………………………………………………………………..As spent nuclear fuel continues to accumulate in Japan, the government claims that it can be reduced by reprocessing. If so, the reduction cost can be estimated as ¥488 million ($3.3 million) per ton.^[5] That’s an emission reduction cost per ton 300,000 times higher than for other mitigation measures indicated by the IPCC. Moreover, spent nuclear fuel does not disappear through reprocessing. Even at the end of a closed fuel cycle, the reprocessed and recycled used fuel will require permanent geological disposal, which comes with its own set of challenges. That’s particularly the case with MOX fuel, which generates high decay heat associated with plutonium and accumulated minor actinides.

Advocates of nuclear power argue that combining fast reactors and transmutation technology after reprocessing can reduce the volume of high-level radioactive waste. But, beyond their many scientific and economic challenges, those measures will not be available in time to solve the climate change crisis, which requires immediate solutions. The only way to stop the generation of spent nuclear fuel is to stop operating nuclear reactors in the first place.

The myth of nuclear power disappears. The Fukushima accident demonstrated—once again—that the claimed inherent safety of nuclear power is a myth. Japan’s reduced reliance on nuclear power since the accident has now also debunked a second myth—that the Japanese society needs nuclear energy. The government’s reversal of its passive stance in favor of a proactive nuclear power policy goes against the current facts. It should revise its energy plan accordingly.

Unfortunately, the new Japanese cabinet formed this October, like its predecessors, is sidestepping the many current and future challenges of nuclear power………………………… As long as the government continues to avoid confronting the difficult reality of nuclear power in Japan, the myth will go on. Until it doesn’t.

Notes…………………….
https://thebulletin.org/2025/12/nuclear-powers-role-in-japan-is-fading-the-myths-of-reactor-safety-and-energy-needs-cant-change-that-reality/

December 22, 2025 - Posted by Christina Macpherson | Japan, politics