Japan to restart world's biggest nuclear plant next week

TOKYO

This photo shows the reactor startup procedure for Unit 6 at the Tokyo Electric Power Company Kashiwazaki-Kariwa Nuclear Power Plant's central control room in Kariwa Village, Niigata Prefecture on Jan. 21, 2026.

Japan will switch the world's largest nuclear power plant back on next week, after a glitch with an alarm forced the suspension of its first restart since the 2011 Fukushima disaster.

Takeyuki Inagaki, the head of the Kashiwazaki-Kariwa plant run by Tokyo Electric Power (TEPCO), told a press conference on Feb. 6 that they planned "to start up the reactor on Feb. 9."

The announcement came after TEPCO restarted the reactor on Jan. 21 but shut it off the following day after an alarm from the monitoring system sounded.

Due to an error in its configuration, the alarm had picked up slight changes to the electrical current in one cable even though these were still within a range considered safe, Inagaki said.

The firm has now changed the alarm's settings as the reactor is safe to operate, Inagaki said.

The commercial operation will commence on or after March 18 after another comprehensive inspection, he said.

Kashiwazaki-Kariwa is the world's biggest nuclear power plant by potential capacity, although just one reactor of seven will restart.

The facility had been offline since Japan pulled the plug on nuclear power after a colossal earthquake and tsunami sent three reactors at the Fukushima atomic plant into meltdown in 2011.

Resource-poor Japan now wants to revive atomic energy to reduce its reliance on fossil fuels, achieve carbon neutrality by 2050 and meet growing energy needs from artificial intelligence.

Kashiwazaki-Kariwa is the first TEPCO-run unit to restart since 2011. The company also operates the stricken Fukushima Daiichi plant, now being decommissioned.