A Japanese nuclear reactor that restarted last week for the first time in more than 13 years after it had survived a massive 2011 earthquake and tsunami that badly damaged the nearby Fukushima nuclear plant was shut down again on Monday due to an equipment problem.

The No 2 reactor at the Onagawa nuclear power plant on Japan’s northern coast was put back online on October 29 and had been expected to start generating power in early November.

But it had to be shut down again five days after its restart due to a glitch that occurred on Sunday in a device related to neutron data inside the reactor, plant operator Tohoku Electric Power Co said.

The reactor was operating normally and there was no release of radiation into the environment, Tohoku Electric said. The utility said it decided to shut it down to re-examine equipment to address residents’ safety concerns. No new date for a restart was given.

The reactor is one of three at the Onagawa plant, which is 100 kilometres (62 miles) north of the Fukushima Daiichi plant where three reactors melted following a magnitude 9.0 earthquake and tsunami in March 2011, releasing large amounts of radiation.

The Onagawa plant was hit by a 13-metre (42-foot) tsunami triggered by the quake but was able to keep its crucial cooling systems functioning in all three reactors and achieve their safe shutdowns.

All of Japan’s 54 commercial nuclear power plants were shut down after the Fukushima disaster for safety checks and upgrades. Onagawa No 2 was the 13th of the 33 still useable reactors to restart.

Japan’s government last year adopted a plan to maximise use of nuclear energy and is pushing to accelerate reactor restarts to secure a stable energy supply and meet its pledge to reach carbon neutrality by 2050.

Concern about the government’s revived push for nuclear energy grew after a magnitude 7.5 earthquake hit Japan’s Noto Peninsula on January 1, 2024, killing more than 400 people and damaging more than 100,000 structures.

It caused minor damage to two nearby nuclear facilities, and evacuation plans for the region were found to be inadequate.