TEPCO to shut reactor at world's biggest nuclear plant a day after resumption

TEPCO halts No.6 reactor at Kashiwazaki-Kariwa a day after its first restart in 13 years to investigate a malfunction, raising concerns over the plant’s operations.

Reuters

22 January 2026 at 08:49:21

TEPCO to shut reactor at world's biggest nuclear plant a day after resumption

Operators carry out reactor startup operations in the central control room of Unit 6 at Tokyo Electric Power Company (TEPCO)'s Kashiwazaki Kariwa nuclear power plant in Kashiwazaki, Niigata prefecture, Japan, January 21, 2026, in this photo released by Kyodo.

Kyodo/Reuters

Tokyo Electric Power 9501.Twill shut down the No.6 reactor at the Kashiwazaki-Kariwa nuclear power plant after a malfunction was detected early on Thursday, a day after the unit went online for the first time in more than 13 years.

In early hours of Thursday, an alarm was triggered during work to withdraw control rods from the reactor, TEPCO said in a statement, adding it would stop the reactor to investigate the cause of the malfunction.

It did not say when the reactor could be restarted.

TEPCO restarted the No.6 unitat Kashiwazaki-Kariwa, the world's biggest nuclear power plant, on Wednesday evening in what was its first nuclear reactor to be turned on since the Fukushima disaster in 2011.

The process had been delayed from Tuesday as TEPCO investigated an alarm malfunction. As of early Wednesday, the equipment in question was functioning normally, TEPCO said at the time.

Shares in TEPCO lost 3.5% on Thursday, underperforming the benchmark Nikkei share average .N225, which gained 1.7%.

-Satoshi Sugiyama, Chang-Ran Kim, Yuka Obayashi and Katya Golubkova/Reuters