The company involved in the 2011 disaster restarted one of seven reactors at Kashiwazaki-Kariwa, the world’s biggest nuclear power plant, in a test for Japan’s nuclear power industry.

Inside the reactor building at the Kashiwazaki-Kariwa nuclear power station in Japan in 2024.Yuichi Yamazaki / AFP - Getty Images

Tokyo Electric Power on Wednesday restarted a reactor at the Kashiwazaki-Kariwa nuclear power plant after inspections were completed, its first such move since the Fukushima disaster in 2011.

TEPCO put online the 1.36 gigawatt (GW) reactor No. 6, one of seven at Kashiwazaki-Kariwa, the world`s biggest nuclear power station capable of producing 8.2 GW of electricity when at full capacity.

The process was delayed from a day earlier as TEPCO was investigating an alarm malfunction. As of early Wednesday, the equipment in question was functioning normally, TEPCO said.

The restart is "a major turning point" for the government, said Filippo Pedretti, a nuclear and thermal power analyst with Japan NRG in Tokyo.

"It signals the end of the post-Fukushima nuclear stalemate and reaffirms the importance of the atom for a stable power supply," he said. "If even TEPCO, the utility involved in the Fukushima Daiichi disaster, can restart its most important plant, other facilities can follow."

Reactor No. 6 is expected to restart commercial operation, increasing the power supply in the Tokyo area - Japan`s busiest - by the end of February. Reactor No. 7 is expected to be brought online around 2030 and some others could be decommissioned.

The revival of Kashiwazaki-Kariwa brings the total number of reactors in Japan currently restarted to 15, out of the 33 reactors that remain operable after the shutdown of Japan`s entire fleet of 54 reactors in the wake of TEPCO`s Fukushima Daiichi reactor meltdown in 2011.

Prime Minister Sanae Takaichi is pushing for the construction of new reactors, especially new-generation and small modular reactors (SMRs), with the government recently announcing a new public funding scheme to accelerate a nuclear power comeback.

After setbacks in its offshore wind roll-out and inflation pressure from fossil fuel imports, Japan is switching its attention to nuclear power again to increase energy security and reduce gas and coal purchases.

Commodity analysts at Kpler expect liquefied natural gas imports by Japan, one of the world`s top buyers along with China, to drop by 4 million metric tons in 2026 from a year earlier to 62 million tons due to higher nuclear power availability with the restarting of reactor No. 6.

"The importance of restarting reactor (No. 6) is increasing from the perspective of controlling electricity supply and demand, electricity tariffs and securing decarbonized power sources," Japan‘s Chief Cabinet Secretary Minoru Kihara said Wednesday.

Kashiwazaki-Kariwa`s restart, the first for TEPCO since the Fukushima disaster, is a major test for the entire Japanese nuclear power industry, as six reactors operated by other utilities, including Chubu Electric Power Co., are awaiting regulatory decisions on their potential restarts.

The developments are also in focus as Japan seeks to increase cooperation with the U.S., its closest ally, on new-generation nuclear reactors and SMRs, with the global atomic industry largely dominated by China and Russia.

This month, Japan`s Nuclear Regulation Authority said it would order Chubu Electric to provide a detailed report on falsified seismic data and pause a review of the utility`s application to restart Hamaoka, its only atomic plant, as public support for greater usage of nuclear power remains divided.

"While other reactors are unlikely to be halted because of this issue, the NRA may increase scrutiny of all utilities," Pedretti said. "Confidence in nuclear operators is paramount."