Restarted Reactor Key Milestone in Japan Energy Policy Aiming to Harness Nuclear Power

By Hiroaki Otake and Hiroyuki Kume / Yomiuri Shimbun Staff Writers

17:13 JST, January 22, 2026

With the twist of a lever, the No. 6 reactor at the Kashiwazaki-Kariwa nuclear power station in Niigata Prefecture was restarted Wednesday, a significant milestone in the government’s plan to make “maximum use” of nuclear energy.

Nuclear power, a carbon-free power source that will help ensure a stable electricity supply, is crucial for people’s day-to-day lives and industrial activity, so the government plans to speed up the restart of more reactors around the nation.

At 6:52 p.m., an operator in the No. 6 reactor’s central control room received an instruction: “Turn on the reactor mode switch.” The operator turned the lever and began the process of activating the reactor, which has an output of about 1.36 million kilowatts and is among the largest in Japan.

Control rods that suppress nuclear fission inside the reactor were pulled out at 7:02 p.m., and four yellow lights on the control panel turned off. This indicated that the reactor was operating for the first time in 13 years and 10 months. The operator continued working while closely checking the meters and gauges to ensure no abnormalities occurred.

Tokyo Electric Power Company Holdings, Inc. plans to start commercial operation of the reactor as soon as Feb. 26. Electricity generated by the reactor will be supplied to the Tokyo metropolitan area. This will substantially stabilize the Tokyo area’s power supply, which had repeatedly been stretched due to high electricity demand during summer and winter.

Momentum growing in eastern Japan

The government approved a revised Strategic Energy Plan at a cabinet meeting in February 2025. The revised plan stated that nuclear power would be utilized to the “maximum” extent possible, and removed wording from the previous plan that called for the nation to “reduce dependence” on this power source. The government has set a target of having nuclear power account for 20% of Japan’s energy mix by fiscal 2040, up from the current level of less than 10%. Achieving this goal will require rebooting the majority of the nation’s 33 nuclear reactors.

However, just 15 reactors, including the Kashiwazaki-Kariwa plant’s No. 6 unit, have been brought back online. Only two of these reactors are in eastern Japan, and power bills charged by TEPCO are at least 10% higher than those issued by Kansai Electric Power Co. and Kyushu Electric Power Co., which have been able to restart more reactors.

In November, Niigata Gov. Hideyo Hanazumi officially approved the restart of the No. 6 reactor, and Hokkaido Gov. Naomichi Suzuki in December gave the green light to restarting the No. 3 reactor at Hokkaido Electric Power Co.’s Tomari nuclear power plant.

Hokkaido Electric plans to cut electricity bills for households by 11% if the Tomari reactor resumes operating.

TEPCO has set its current electricity rates based on the assumption that the Nos. 6 and 7 reactors at the Kashiwazaki-Kariwa plant will get up and running. Although the No. 6 unit has restarted, “this won’t have an immediate impact on power bills,” a TEPCO official said. However, the restart could lead to lower bills in the future.

Worldwide trend

The government’s urgency to restart nuclear reactors is motivated in part by the direct connection this issue has with Japan’s industrial competitiveness. Expanding usage of nuclear power is a global trend. In 2024, U.S. tech giant Microsoft Corp. signed a contract to purchase electricity from the Three Mile Island nuclear power plant in the northeastern United States for 20 years. U.S. companies Google LLC and Amazon.com, Inc. have also announced plans to make massive investments in next-generation reactors.

The administration of Prime Minister Sanae Takaichi has pledged to pour money into fields such as artificial intelligence and semiconductors as part of an economic growth strategy. All these fields consume vast amounts of electricity, so the nation’s demand for power will certainly increase.

Consequently, there are mounting concerns within the government about what could happen if the nation does not fully harness nuclear power. “We’ll be left behind in global competition,” a senior Economy, Trade and Industry Ministry official told The Yomiuri Shimbun.

Waseda University Prof. Noriko Endo, an expert on nuclear power, said, “Creating a stable supply of electricity will impact every industry, ranging from automobiles to defense. It’ll affect our nation’s strength.”