Japan restarts its biggest nuclear plant: When was it shut and what were the issues

Japan has restarted a reactor at the Kashiwazaki-Kariwa Nuclear Power Plant, the world’s largest nuclear facility by capacity, marking another step in the country’s slow return to atomic energy.

This comes more than a decade after the 2011 Fukushima disaster forced a nationwide shutdown of reactors.

Japan restarts reactor at Kashiwazaki-Kariwa plant, but why now?

Operator Tokyo Electric Power Company (TEPCO) said reactor No. 6 was switched back on Monday afternoon. An earlier restart attempt in January was halted after a monitoring alarm flagged minor electrical current changes, according to Japan Today.

Officials later said readings were within safe limits and adjusted the system settings.

Commercial operations are expected after further checks, possibly later in March.

Japan is pushing nuclear power again as it tries to cut fuel imports, lower carbon emissions by 2050, and meet rising electricity demand linked to data centers and AI infrastructure.

Why Japan shut reactors after Fukushima

Kashiwazaki-Kariwa had been offline since the 2011 earthquake and tsunami that caused meltdowns at Fukushima Daiichi Nuclear Power Plant. After that disaster, all of Japan’s 54 reactors were taken offline under tighter rules, per BBC reports.

The Niigata facility later underwent major upgrades, including a 15-meter tsunami wall and elevated emergency power systems. Even so, trust issues linger. Local surveys show public opinion remains divided.

Safety upgrades and oversight checks

The plant has faced scrutiny over internal management. In recent years, employees misplaced sensitive documents in separate incidents.

TEPCO reported the cases to Japan’s nuclear watchdog, the Nuclear Regulation Authority, and said oversight procedures were strengthened.

Critics argue the company still struggles to rebuild confidence after Fukushima. An earlier independent inquiry called that accident a ‘man-made disaster’ - though courts later cleared former executives of criminal negligence.

Where Japan’s nuclear restart programme stands

Fourteen reactors nationwide have restarted since 2011 under stricter rules.

Kashiwazaki-Kariwa is the first TEPCO-run unit to return. Other reactors at the site may remain offline for years, and some could be decommissioned.

Public opinion has shifted over time. Surveys by Pew Research Center showed opposition spiking after 2011, while later domestic polls suggested cautious support if safety is assured.