Amid energy challenges and green shift, Japan eyes new nuclear tech

Amid energy security concerns heightened by the war in Ukraine, the government has steadily moved toward a stronger embrace of nuclear power, with Prime Minister Fumio Kishida stating his intention to get more idled reactors back online. But late last month he seemed to go further, indicating that he wants to look at constructing new types of reactors.

The comments, made at an Aug. 24 meeting of experts debating a new green transformation policy, have been taken as a fundamental policy shift that could see Japan pursue smaller nuclear reactors. Supporters tout these as safer and more economically efficient. But massive political, economic and environmental challenges could greatly drive up costs.

Kishida’s policy on green transformation — referred to as "GX" in Japan — aims to give the nation the ability to meet both short-term electricity supply problems in the future and the country’s decarbonization goals. The government aims to have renewable energy provide 36% to 38% of its power by 2030, with nuclear accounting for 20% to 22%, and it has a goal of achieving full carbon neutrality by 2050.

On Aug. 2, then-economy minister Koichi Hagiuda said that while a committee within the ministry's Agency for Natural Resources has indicated that new reactors could be commissioned by mid-2030, that does not mean the government intends to newly construct or replace existing ones.

Just over three weeks later, the prime minister appeared to contradict that statement.

“We’ll take all possible measures to overcome the current crisis of tight supply and demand of electricity," Kishida said on Aug. 24. "This meeting has also called for the development and construction of next-generation innovative reactors that incorporate new safety mechanisms.”

In an Aug. 31 news conference, however, Kishida denied Japan was changing course on its energy goals.

“To achieve the 2030 and 2050 greenhouse gas goals, we asked experts to consider all options, including next-generation reactors. But our policy of reducing dependence on nuclear power as much as possible remains unchanged,” he said.

The green transformation panel is expected to deliver its recommendations to the Kishida administration by the end of the year. But the committee's support for restarting more large-scale nuclear reactors and developing small modular reactors (SMRs), a controversial new technology that has yet to be commercialized, appears strong.

“We should take urgent measures to accelerate the restart of nuclear power plants this autumn,” Japan Business Federation Chairman Masakazu Tokura said at the Aug. 24 meeting. He also spoke of the need to develop SMRs.

Apart from the challenges posed by that new nuclear technology, ramping up nuclear in general faces hurdles of its own.

At the moment there are 10 reactors in operation, and Kishida spoke last month of restarting seven others as soon as possible. These reactors are undergoing safety upgrades but have already received approval from the Nuclear Regulation Authority to go back online once the safety work has been completed.

Another 10 are still undergoing safety inspections and are waiting for final NRA approval to go back into operation. Of the remaining 33 reactors, though, 24 are being decommissioned, while restart applications have not yet been submitted for the remaining nine.

Reactors over 40 years old may continue operating for an additional 20 years if they meet additional safety regulations.

Of Japan’s four reactors over four decades old, only Kansai Electric Power Co.’s 45-year-old Mihama No. 3 reactor has actually been restarted. Restarts have been approved for two other Kepco reactors over 45, but these nonetheless face the prospect of being decommissioned. The restart of the 43-year-old Tokai Daini plant in Ibaraki Prefecture, meanwhile, has been halted due to a local court ruling, which criticized local evacuation plans as insufficient.

Mika Obayashi, director of the Tokyo-based Renewable Energy Institute, a nonprofit think tank that advises the government, said there are fundamental problems with ramping up nuclear power — ranging from high costs to accident risks, as well as the length of time required to get new facilities running.

“It takes decades for new nuclear power plants to be built and go into operation," she said. "It’s not a solution to urgent electricity shortages. New plants would not come online in time to meet the 2030 emissions goals and reach carbon neutrality by 2050."

There is also the issue of what to do with additional nuclear waste — which needs to be safely stored for 100,000 years — when Japan has yet to find a site for the final disposal of the spent nuclear fuel from its existing reactors.

In addition, separate plans to recycle spent fuel for reuse in Rokkasho, Aomori Prefecture, have stalled. On Sept. 7, completion of Rokkasho’s fuel reprocessing plant was delayed for the 26th time. No new completion target has been set and there are no estimates on when spent fuel might be reprocessed there to be burned as fuel once again.

Thus, efforts to quickly restart current, conventional reactors already face a variety of challenges. But Kishida’s announcement that the government would also look at SMRs raises questions of its own, not least because the technology is not yet commercially available.

Unlike conventional nuclear reactors, SMRs have a capacity of up to 300 megawatts per unit. That's about one-third of the generating capacity of traditional nuclear power reactors, but SMRs can be located in places not suitable for larger nuclear power plants.

SMR proponents and the International Atomic Energy Agency (IAEA) argue that, compared with large reactors, SMRs are cheaper and take less time to construct. Although their electricity output is smaller than conventional reactors, a series of them can be used to match supply to demand incrementally and more efficiently than larger conventional reactors.

The challenges, however, are immense — starting with the fact that there are no commercial SMRs currently operating.

In a June report, the IAEA said that while it expects SMRs to account for a greater share of new nuclear capacity additions worldwide after 2030, that’s under the assumption there is progress in developing and demonstrating SMR technology and bringing down costs.

Uncertainties about when SMRs will be ready for commercial deployment on a competitive scale make it difficult to project their ability to help meet various decarbonization goals.

While supporters say SMRs will ultimately have lower operating costs once they go into commercial operation, the problem of waste disposal remains. In late May, research by Stanford University in California and the University of British Columbia in Vancouver found that small modular reactors might have bigger problems with radioactive waste disposal, raising costs and triggering environmental concerns.

“Some SMR reactor designs call for chemically exotic fuels and coolants that can produce difficult-to-manage wastes for disposal,” said co-author Allison Macfarlane, a professor at the the University of British Columbia's School of Public Policy and Global Affairs. “Those fuels and coolants may require costly chemical treatment prior to disposal. The takeaway message from the study is that the back end of the SMR nuclear fuel cycle may include hidden costs that must be addressed,” she added.

Finally, Japan would also have to consider the national security implications of ramping up nuclear power. Russia’s alleged shelling of the Zaporizhzhia nuclear power plant has only heightened international concern about how to protect such facilities in the event of conflict.

“Russia's invasion of Ukraine has shown nuclear power plants make national security extremely vulnerable. New nuclear plants will increase that vulnerability,” Obayashi said.