Japan’s TEPCO restarts first nuclear reactor since Fukushima

21 January 2026

Tokyo Electric Power Company (TEPCO) restarted a reactor at the Kashiwazaki-Kariwa nuclear power plant. TEPCO put online the 1.36 GW reactor No. 6, one of seven at Kashiwazaki-Kariwa, once the world’s biggest nuclear power plant with a nameplate capacity of 8.2 GW.

The move marks the first reactor restart by TEPCO—Japan’s largest utility—after the 2011 earthquake and tsunami that led to the major nuclear accident at the company’s Fukushima Daiichi power plant.

Kashiwazaki-Kariwa reactor No. 6 is expected to restart commercial operation by the end of February. Reactor No. 7 is expected to be brought online around 2030, while some other reactors at the Kashiwazaki-Kariwa power plant can be decommissioned.

The restart of Kashiwazaki-Kariwa brings the total number of reactors currently in operation in Japan to 15, according to the World Nuclear Industry Status Report. A further 18 reactors are shut down but remain operable after the shutdown of Japan’s entire fleet of 54 reactors in the wake of the Fukushima Daiichi accident.

Japan now looks to have 20% of its electricity generation coming from nuclear power by 2040, up from 8.4% today.

Source: TEPCO