Japan’s Nuclear Restart Strategy Faces Critical Spent Fuel Storage Crisis

Japan is accelerating the restart of its nuclear power fleet to meet rising electricity demand, yet the policy faces a significant logistical hurdle: the nation’s spent nuclear fuel storage capacity is reaching its limit. With cooling pools at nuclear power stations nearing capacity, the government is currently evaluating the feasibility of using remote islands, including Minamitorishima, as potential sites for long-term radioactive waste management, according to the Ministry of Economy, Trade and Industry (METI).

Why Is Japan’s Nuclear Waste Storage at Capacity?

The primary issue lies in the accumulation of spent fuel that has outpaced the development of permanent disposal infrastructure. As of late 2025, cooling pools at 17 Japanese nuclear plants held over 17,000 tons of spent fuel, utilizing approximately 80% of their total storage capacity, per METI data. Since the 2011 Fukushima Daiichi disaster, which led to a nationwide shutdown of reactors, Japan has struggled to implement a closed nuclear fuel cycle. The process of recycling fuel into plutonium and uranium has faced technical and economic setbacks, forcing utilities to rely on temporary on-site storage. Without a viable permanent disposal facility, operators like Tokyo Electric Power Company (TEPCO) are increasingly forced to move fuel between reactors or pursue dry-cask storage to prevent operational stalls.

Is Minamitorishima a Viable Disposal Site?

The Japanese government is exploring Minamitorishima, a remote island located roughly 2,000 kilometers south of Tokyo, as a potential candidate for high-level radioactive waste disposal. Industry Minister Ryosei Akazawa has requested a feasibility study to determine if the island’s geological stability makes it suitable for long-term storage. However, the proposal has encountered significant public and political resistance. Critics, including local assembly members in Ogasawara, argue that the island’s status as a UNESCO Natural World Heritage site makes it incompatible with a nuclear dump. Furthermore, observers like Satoshi Takano, a member of a government panel on waste disposal, have characterized the move as a political calculation, noting that the government-owned island lacks a permanent population that could organize effective opposition.

How Does Japan’s Approach Compare to Global Standards?

Japan’s reliance on reprocessing spent fuel stands in contrast to the shifting strategies of other major economies. While Japan continues to pursue a closed fuel cycle to extract plutonium, nations such as the United Kingdom, Germany, and the United States have largely abandoned the practice due to prohibitive costs and technical complexity, opting instead to prioritize direct disposal. Finland represents the global benchmark for this approach; the country is preparing to open the world’s first permanent geological repository for spent nuclear fuel. Unlike Japan’s ongoing search for a site, Finland’s Onkalo repository was designed for long-term safety and has already secured community support after decades of planning.

Key Challenges for Future Nuclear Energy Policy

• Regulatory Hurdles: Establishing a final repository requires a process spanning roughly 100 years, according to environmental politics expert Lila Okamura of Senshu University.
• Safety Concerns: High-density storage in cooling pools increases the risk of overheating, prompting calls from civil activists for a halt to reactor restarts until a final destination for waste is confirmed.
• Financial Incentives: The government offers substantial subsidies—up to 9 billion yen in the initial stages—to municipalities that agree to host feasibility studies, yet finding a willing host remains difficult.

As Prime Minister Sanae Takaichi continues to advocate for the expansion of nuclear energy to secure Japan’s power grid, the gap between energy production and waste management continues to widen. The government faces the difficult task of balancing immediate energy security needs with the multi-generational responsibility of managing highly radioactive materials.