Fifteen years after the Fukushima disaster turned Japan into a cautionary tale for nuclear energy, Tokyo is making a sharp U-turn. The country’s Ministry of Economy, Trade and Industry (METI) introduced a draft policy on June 5 proposing to replace between 11 and 14 aging nuclear reactors by the 2050s, a move designed to keep up with surging electricity demand from AI data centers and semiconductor fabs.
This is the first time since the 2011 meltdown that Japan has put explicit numbers on reactor replacements.
What the proposal actually says
The METI draft lays out a phased timeline. In the near term, Japan targets 2 to 5 reactor replacements by the 2040s, adding roughly 2 to 5.5 gigawatts (GW) of capacity. The bigger push comes in the following decade, with 11 to 14 reactors slated for the 2050s, translating to 12.7 to 16 GW of new capacity.
If fully realized, the reactor rebuilds could deliver a total of approximately 16 GW. Japan currently has about 33 GW of total nuclear capacity spread across 15 operating reactors, following the restart of the Kashiwazaki-Kariwa Unit 6 earlier in 2026.
The overarching goal is to maintain nuclear energy’s contribution at roughly 20% of Japan’s electricity mix by 2040. Imported hydrocarbons currently account for 60-70% of the country’s power generation.
Cabinet approval for the policy is expected during the summer of 2026.
Why now: AI, chips, and energy security
Japan’s electricity demand is climbing, driven by three hungry sectors: artificial intelligence infrastructure, data centers, and semiconductor manufacturing.
Japan’s position is also shaped by geography and geopolitics. As an island nation with virtually no domestic fossil fuel reserves, importing 60-70% of electricity generation fuel represents a direct vulnerability.
The Fukushima disaster led to a near-total shutdown of Japan’s reactor fleet. In the years since, the country has been restarting reactors and extending their operational lifetimes. This proposal represents the logical next step: not just restarting old plants, but actually building replacements for ones that have aged out.
What this means for energy investors
Building or replacing 14 reactors is a multi-decade undertaking that touches everything from uranium supply chains to specialized construction firms to reactor technology providers.
The uranium market is worth watching closely. Japan already operates 15 reactors. Adding up to 14 more, even on a replacement basis, would substantially increase the country’s uranium procurement needs over time.
The risk side of the equation hasn’t disappeared. The Fukushima disaster displaced over 150,000 people. Any seismic event or safety incident during the buildout period could derail the entire program.
Cabinet approval this summer would be just the starting gun for a process involving environmental reviews, local government approvals, and construction timelines that routinely stretch past initial estimates.