Tokyo Report | Environment | East Asia

Japan’s Nuclear Revival Has a Trust Problem

Prime Minister Takaichi Sanae has made it clear that the nuclear restart is part of the answer to Japan’s energy uncertainty, but questions remain about safety and accountability.

Kashiwazaki-Kariwa Nuclear Power Plant as viewed in 2014.

When Tokyo Electric Power Company (TEPCO) brought Unit 6 at Kashiwazaki-Kariwa back online in January, it became the first TEPCO reactor to resume since the Fukushima Daiichi accident. An alarm halted the restart the next day; the unit resumed operation in February and entered commercial service in April. Unit 7 at Kashiwazaki-Kariwa, meanwhile, is not expected to restart before 2029–30, according to the EIA.

Clearly, the restart announcement in January was a bit of a false start. Still, the symbolism was unmistakable: The utility responsible for Fukushima is again operating a nuclear plant, the world’s largest by installed capacity.

The timing was also consequential. The Israeli-Japan strikes on Iran on February 28 and the resulting effective closure of the Strait of Hormuz exposed Japan’s reliance on imported energy. In 2025, the Middle East supplied 94 percent of Japan’s crude oil imports; 93 percent of the country’s crude imports passed through Hormuz, according to Reuters. 

Japan’s exposure to Hormuz through LNG is much smaller: around 6 percent of total LNG imports, according to IEEFA. Yet Japan imports more than 97 percent of the LNG it consumes, and LNG generates about a third of Japan’s electricity, according to the government’s 2025 energy overview. The Hormuz shock therefore mattered both as a direct risk to Japan’s oil supply and as the cause of higher global gas and electricity prices.

The International Energy Agency reported that Japanese wholesale spot electricity prices in the second quarter of 2026 were more than 30 percent higher year on year. Futures in mid-July pointed to prices in the second half of 2026 nearly 40 percent above the same period a year earlier. These are wholesale-market figures, not household bills, but they show how a disruption to a relatively small share of Japan’s direct LNG supply can still transmit through global markets.

Prime Minister Takaichi Sanae has made it clear that the nuclear restart is part of the answer to Japan’s energy uncertainty. She said in March that the newly reopened Kashiwazaki-Kariwa Unit 6, combined with a temporary increase in coal-fired generation, could cut Japan’s LNG imports passing through Hormuz by about 40 percent. 

That logic extends beyond the Gulf. A country dependent on LNG imports for a large share of its electricity is exposed to disruptions elsewhere in the Indo-Pacific, including scenarios involving shipping routes around Taiwan or in the East China Sea. For example, Japan’s continued reliance on Russian LNG has become a problem. The Sakhalin-II supply relationship has become a question of energy security, diplomacy, and policy autonomy. 

The strategic case for nuclear power is therefore not just about decarbonization or energy bills. It is also about preserving Tokyo’s strategic autonomy by reducing its reliance on overseas energy providers. 

Japan’s nuclear energy targets remain well ahead of the fleet it can count on today. The government’s Seventh Strategic Energy Plan set a target for nuclear power to supply about 20 percent of electricity generation in fiscal year 2040. The U.S. Energy Information Administration (EIA) estimated that meeting that target would require up to 30 reactors in operation. As of September 16, the latest date on the Nuclear Regulation Authority’s operating-status register, 11 reactors were classified as “Operation.” 

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