Kashiwazaki-Kariwa

The Kashiwazaki-Kariwa Nuclear Power Plant was built in phases between 1985 and 1997 along the Sea of Japan coast in Niigata Prefecture. It comprises seven reactors—five conventional boiling-water reactors (BWRs) and two Advanced Boiling Water Reactors (ABWRs). Units 6 and 7, the ABWRs, were the world's first commercial ABWRs when they entered service in 1996 and 1997.

At 7,965 MW of installed capacity, Kashiwazaki-Kariwa is the largest nuclear power plant in the world. Before the 2011 Fukushima disaster, it produced roughly 6% of Japan's electricity. The plant has been mostly idle since 2011, with TEPCO and Japanese regulators working through extensive post-Fukushima safety upgrades. In late 2024, regulators cleared the plant for restart pending local government consent.

When operating at full capacity, Kashiwazaki-Kariwa displaced roughly 30 million tonnes of CO2 emissions per year that would otherwise have come from fossil-fueled generation. Its prolonged shutdown has been a major contributor to Japan's slow progress on emissions reductions; the country was forced to rely heavily on imported LNG and coal to fill the gap.

In 2007 the plant was damaged by the Chūetsu offshore earthquake, prompting a 21-month shutdown. After Fukushima in 2011, the entire site was shut down for safety reviews. TEPCO's handling of physical security at the plant—including unauthorized access incidents disclosed in 2020 and 2021—drew sharp criticism from the Nuclear Regulation Authority. Local officials have had reservations about restart authority for the same operator that ran Fukushima Daiichi.

• The plant complex covers 4.2 square kilometres—about the size of Monaco.
• Kashiwazaki-Kariwa Unit 6 was the first commercial Advanced Boiling Water Reactor in the world.
• TEPCO operates this plant and also operated the Fukushima Daiichi plant, which suffered the 2011 disaster.
• If fully restarted, Kashiwazaki-Kariwa would once again become Japan's single largest source of electricity.