Japan shuts reactor at world’s biggest nuclear plant a day after restart

The restart of a reactor at the world’s largest nuclear power plant has been suspended in Japan, a day after the process began, its operator, which also manages the wrecked Fukushima plant, said. But the reactor remains “stable”.

The No 6 reactor at the Kashiwazaki-Kariwa plant in north-central Japan – closed since the 2011 Fukushima disaster – reactivated on Wednesday as plant workers started removing neutron-absorbing control rods from the core to start stable nuclear fission.

But the process had to be suspended hours later due to a malfunction related to control rods, which are essential to safely starting up and shutting down reactors, the Tokyo Electric Power Company Holdings (TEPCO) said. The duration of the shutdown was still unknown.

TEPCO said there was no safety issue from the glitch and it was checking the situation while suspending the restart operation. The utility later said it was putting the reactor back into shutdown for a fuller examination.

“We were investigating the malfunctioning electrical equipment”, spokesperson Takashi Kobayashi told the AFP news agency.

The reactor “is stable and there is no radioactive impact outside”, he said.

Control rods are a device used to control the nuclear chain reaction in the reactor core, which can be accelerated by slightly withdrawing them, or slowed down or stopped completely by inserting them deeper.

The restart, initially scheduled for Tuesday, had been pushed back after another technical issue related to the rods ‘ removal was detected last weekend – a problem that was resolved on Sunday, according to TEPCO.

Kashiwazaki-Kariwa is the world’s biggest nuclear power plant by potential capacity, although just one reactor of seven was restarted.

The facility was taken offline when 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.

However, 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.

Fourteen other nuclear reactors have restarted across Japan since 2011, but the Kashiwazaki-Kariwa plant, about 220 kilometres (135 miles) northwest of Tokyo, is the first TEPCO-run unit to resume production.

The company also runs the decommissioned Fukushima Daiichi plant, which has been severely damaged.

More than 1 million households in the capital region could be fueled by a restart of the No 6 reactor, which would generate an additional 1.35 million kilowatts of electricity.

According to a survey conducted in September, Niigata’s public opinion is polarized: about 60% of residents oppose the restart, while 37% support it.

Why should the people of Kashiwazaki be in danger if Tokyo produces electricity there? This makes no sense, Yumiko Abe, a 73-year-old resident, claimed this week during a protest in front of the plant.