Japan Could Be Nearing Restart of World's Largest Nuclear Power Plant

The world’s largest nuclear power plant, among the facilities taken offline after the 2011 Fukushima disaster in Japan, could be nearing a restart.

Japanese media reported that on March 14, Takeshi Saito—Japan’s minister of Economy, Trade and Industry—asked Hideyo Hanazumi, the governor of Niigata Prefecture, for permission to restart the first of seven reactors at the Kashiwazaki-Kariwa nuclear facility. Local officials must sign off on any reopening of a nuclear power plant in Japan since the country took all its nuclear reactors offline after Fukushima.

Media reported that a government official with Saito’s ministry is scheduled to meet with Hanazumi on March 21. Reports said this is the first time the Japanese government has directly requested a restart for Kashiwazaki-Kariwa, which is owned and operated by Tokyo Electric Power (TEPCO). The plant has seven reactors, with total generation capacity of almost 8,000 MW.

The meeting scheduled this week comes after Japan’s Nuclear Regulation Authority (NRA) in December gave permission for a restart at Kashiwazaki-Kariwa.

The Kashiwazaki-Kariwa plant was shut down for nearly two years after an offshore earthquake in July 2007. Unit 7, after receiving upgrades to better withstand seismic activity, was restarted in May 2009. Units 1, 5, and 6 were restarted soon after, but the other three units did not restart prior to the Fukushima earthquake and tsunami in March 2011.

Reactors Returning to Service

The U.S. Energy Information Administration (EIA) said that as of year-end 2023, 12 reactors have returned to commercial operation in Japan, with eight reactors planning for a restart. Another five, including Units 6 and 7 at Kashiwazaki-Kariwa, have passed a government safety review; an additional 10 reactors are currently in the review phase, according to EIA. TEPCO has not said whether it will seek to restart Kashiwazaki-Kariwa’s other five reactors.

The footprint of the Kashiwazaki-Kariwa nuclear plant is spread across about 1,000 acres, and is so large it includes parts of two towns in Niigata Prefecture, on the coast of the Sea of Japan. The first five units, each a boiling water reactor, have 1,067 MW of generation capacity and came online between 1985 and 1994. Units 6 and 7, which are advanced boiling water reactors, each have 1,315 MW of capacity. They came online in 1996 and 1997, respectively.

A restart of Units 6 and 7 at Kashiwazaki-Kariwa was approved in 2017, but TEPCO did not resume operations at that time. Reloading of fuel at the plant was approved in December of last year after the NRA signed off on its safety review.

Darrell Proctor is a senior associate editor for POWER (@POWERmagazine).

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