Key facts
- Japan has restarted operations at the Kashiwazaki-Kariwa Nuclear Power Station, the world's largest nuclear plant.
- The restart aims to address high electricity demands amid a global oil crisis.
- Japan is running out of space for spent nuclear fuel, with cooling pools at three plants expected to be full in five years.
- The government is considering Minamitorishima, a remote Pacific island, for radioactive waste disposal.
- Japan's fuel recycling plan has stalled, contributing to the growing stockpile of spent fuel.
- As of December 2025, 17 Japanese nuclear power plants held over 17,000 tons of spent fuel, using nearly 80% of total storage capacity.
Japan has resumed operations at the Kashiwazaki-Kariwa Nuclear Power Station, the world's largest nuclear plant, to bolster electricity supply during a global oil crisis. However, this restart underscores a significant challenge: Japan is rapidly running out of storage space for radioactive waste, with no concrete plans for permanent disposal.
The Kashiwazaki-Kariwa plant's No. 6 reactor was restarted earlier this year, intended to pave the way for bringing more nuclear reactors online across the country. According to the Federation of Electric Power Companies of Japan, three plants, including Kashiwazaki-Kariwa, will have full cooling pools within five years.
"Without solid (fuel management) plans, our power generation will stall sooner or later," stated Takeyuki Inagaki, General Manager of Kashiwazaki-Kariwa. The government is exploring Minamitorishima, a remote Pacific island, as a potential site for high-level radioactive waste, a proposal that has met skepticism due to past arbitrary waste management actions.
Since the March 2011 Fukushima disaster, only 15 of Japan's 54 reactors have been restarted. Kashiwazaki-Kariwa, also operated by TEPCO, was shut down following the disaster. TEPCO has implemented enhanced safety measures, including filtered venting systems, based on Fukushima's lessons.
Japan's strategy for dealing with spent nuclear fuel involves recycling to extract plutonium and uranium, but this plan has faced setbacks, including the failure of a key reactor for plutonium reuse. Reprocessing alone cannot manage all spent fuel, leading to a substantial plutonium stockpile.
As of December 2025, cooling pools at 17 Japanese nuclear power plants contained over 17,000 tons of spent fuel, utilizing nearly 80% of total storage capacity. Lila Okamura, an expert on nuclear waste management, noted that Japan must also contend with significant waste from the Fukushima disaster and emphasized the need for careful, long-term planning for disposal sites, which can take decades to establish and monitor.