Japan reactor restart sparks fresh fears over nuclear waste storage : NPR

KASHIWAZAKI, Japan — Japan’s largest nuclear power plant has resumed operations to address the nation’s substantial electricity needs amid a global oil crisis. However, this move underscores a significant issue: Japan is running out of storage space for spent nuclear fuel, and lacks a long-term solution for disposing of the radioactive waste.

The Kashiwazaki-Kariwa Nuclear Power Station’s No. 6 reactor was restarted earlier this year to encourage the activation of more nuclear reactors. According to the Federation of Electric Power Companies of Japan, Kashiwazaki-Kariwa is among three plants expected to reach full capacity in their cooling pools within five years.

“Without solid (fuel management) plans, our power generation will stall sooner or later,” noted Takeyuki Inagaki, General Manager of Kashiwazaki-Kariwa.

For decades, Japan has sought permanent storage for highly radioactive spent fuel. The government is now considering Minamitorishima, a remote Pacific island south of Tokyo, as a potential site. However, this has sparked criticism due to Japan’s seemingly arbitrary approach to handling spent fuel and radioactive waste.

Since the March 2011 Fukushima disaster, only 15 out of Japan’s 54 reactors have been restarted. The disaster was triggered by a 9.0 magnitude earthquake and subsequent tsunami that led to reactor meltdowns at three Tokyo Electric Power Company Holdings (TEPCO) facilities. Approximately 160,000 people were displaced from Fukushima, with some areas still uninhabitable.

Kashiwazaki-Kariwa, also managed by TEPCO, was shut down following the Fukushima incident as part of a nationwide nuclear power halt.

The cooling pool of Kashiwazaki-Kariwa’s No. 6 reactor is 88% full and visible from a top-floor observation area. TEPCO has implemented new safety measures, including filtered venting systems and hydrogen explosion prevention devices, based on lessons learned from Fukushima.

Prime Minister Sanae Takaichi is advocating for the reactivation of additional nuclear plants, which will inevitably produce more spent fuel. Without a feasible permanent storage plan, there is concern that reactors may need to be shut down once storage space is exhausted.

Fuel recycling plan has stalled

Japan faces two options for dealing with spent nuclear fuel: direct disposal as waste or recycling to extract plutonium and uranium for reuse.

Japan advocates for recycling, believing it will meet the nation’s energy needs while reducing radioactive waste. However, a reactor designed for plutonium reuse has failed, and reprocessing cannot handle all spent fuel. This has led to a plutonium stockpile large enough for thousands of atomic bombs.

Experts suggest Japan should consider direct disposal as an alternative.

As of December 2025, cooling pools at 17 Japanese nuclear power plants held more than 17,000 tons (15,422 metric tons) of spent fuel, nearly 80% of total capacity, according to the Ministry of Economy, Trade and Industry.

Besides the substantial radioactive waste from normal reactors, Japan also faces “massive and largely unknown high-level nuclear waste from the Fukushima disaster,” according to Lila Okamura, a Senshu University expert on nuclear waste management.

Choosing and developing a final disposal site for spent fuel could take 100 years, with thousands of years required for monitoring storage underground. Okamura cautioned that Japan should plan carefully and not rush the current plan, which is fraught with uncertainties.

A remote island is a possibility

Weeks after the No. 6 reactor at Kashiwazaki-Kariwa resumed operations for the first time in 14 years since the Fukushima disaster, Industry Minister Ryosei Akazawa requested a feasibility study for a high-level radioactive waste site on Minamitorishima, an island governed by Ogasawara, part of Tokyo.

“With a lot of spent fuel accumulating at nuclear power plants across the country, a final disposal of radioactive waste is a crucial challenge that must be resolved,” Akazawa wrote to Ogasawara Mayor Masaaki Shibuya.

The government-owned Minamitorishima, located about 2,000 kilometers (1,242 miles) south of Tokyo, has no permanent residents. It hosts a Japanese army firing range for long-range missiles as a deterrent to China and has rich sea deposits of rare earth minerals.

“The move seems political,” commented Satoshi Takano, a member of a government panel examining spent fuel disposal. “There will be little opposition from a government-owned remote island.”

Some experts believe the island, situated on a geologically stable tectonic plate, might be suitable. However, residents on Ogasawara and nearby islands have expressed concerns about safety and tourism.

“I was baffled when I heard about the plan,” said Ogasawara assembly member Yusuke Hirano during an assembly meeting. “I think nuclear waste is incompatible with islands that are a UNESCO Natural World Heritage site.”

Struggling to find a final disposal site

Finding a community willing to host a highly radioactive dump site has been challenging, even with financial incentives. Minamitorishima is the fourth location to undergo a feasibility study since the government’s search began in the early 2000s.

The entire review process is expected to take about two decades. Municipalities in the initial stage can receive up to 2 billion yen ($12.8 million) in government subsidies. The next stage offers up to 7 billion yen ($44.7 million). Funding details for a final study remain undisclosed.

The world’s first final disposal site for spent nuclear fuel is set to open in Finland later this year. Countries like Britain, Germany, and the United States have abandoned reprocessing due to high costs and technical difficulties, while several other nations are exploring direct disposal site plans.

Inagaki, the general manager of Kashiwazaki-Kariwa, stated that TEPCO is transferring spent fuel from the No. 6 reactor to other reactors at the plant with more space and hopes to resume shipments to a dry cask storage facility in northern Japan as a temporary solution. Other utilities with nearly full pools have announced plans to build dry-cask storage at their facilities.

Many residents are concerned about Japan’s increasing stockpile, as high-density storage of spent fuel could elevate overheating risks.

Mie Kuwabara, a civil activist in Niigata, questioned the future of the waste storage. “It’s irresponsible to accelerate restarts and produce more spent fuel without deciding its final destination,” said Kuwabara, who also doubts the suitability of Minamitorishima.

“It’s like saying that it’s OK to put a facility there because nobody is around to complain if there is a problem,” Kuwabara expressed. “It’s scary.”