The Japanese government has decided to rebuild two to five aging nuclear reactors by the 2040s, preparing for rising electricity demand driven by factors such as the operation of artificial intelligence (AI) data centers.
According to NHK and the Nihon Keizai Shimbun (Nikkei) on Friday, the installed capacity of the reactors targeted for rebuilding will reach up to 5.5 million kilowatts (kW), equivalent to about 20% of Japan's total existing nuclear capacity. The Japanese government plans to rebuild 11 to 14 reactors by the 2050s to produce 12.7 million to 16 million kW of power.
The Japanese government cemented its stance of maximizing the use of nuclear power through its basic energy plan last year. Accordingly, it set a goal of raising the share of nuclear power generation, which stood at 9.4% of total electricity in 2024, to 20% by 2040. Nikkei reported, "There are opinions that reactors halted due to safety concerns after the March 2011 Great East Japan Earthquake should be restarted, but many reactors will exceed 60 years of operation by the 2040s, raising aging issues." It added, "Restoring trust is key, as suspicions have been raised that Chubu Electric Power, the operator, used manipulated data during the Nuclear Regulation Authority's review for restarting units 3 and 4 of a nuclear plant in Shizuoka Prefecture."
On March 11, 2011, a magnitude 9.0 Great East Japan Earthquake occurred, and the tsunami it triggered (with a maximum wave height of about 14 to 15 meters) flooded the emergency diesel generators of the Fukushima Daiichi Nuclear Power Plant, resulting in a complete loss of the cooling system. Subsequently, core meltdowns occurred in succession at units 1, 2, and 3, followed by hydrogen explosions, classifying the accident at level 7, the highest level on the International Nuclear and Radiological Event Scale (INES). It is regarded, alongside Chernobyl, as one of the worst nuclear accidents in history.
Japan, which had been trapped in nuclear trauma, began to accelerate reactor restarts from the early 2020s. Last year, Japan's nuclear reactor operation rate was 33.6%, the highest figure since the Fukushima Daiichi explosion. The operation rate represents the ratio of actual power generation to the total power generation that could be obtained if all reactors nationwide were operating.
Japan's nuclear operation rate fell to 0% after the 2011 accident, as decommissioning work and stricter regulations were implemented. It has since gradually recovered, setting new highs each year since 2023. This year, the rate is expected to rise as unit 6 of the Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture, in central Honshu, which has a large generation capacity, is restarted.
However, anxiety over nuclear accidents and distrust of management still remain. Unit 3 of the Mihama Nuclear Power Plant in Fukui Prefecture caused alarm among the Japanese public with a steam leak on the 8th of last month. Safety controversies have also continued, including suspicions that Chubu Electric Power underestimated the magnitude of earthquakes during the review process for restarting the Hamaoka Nuclear Power Plant.
