Kashiwazaki Kariwa-6 May Restart as Early as Next Month

Tokyo Electric Power Co. (TEPCO) announced on December 24 that it had submitted an amended pre-operational inspection application to the Nuclear Regulation Authority (NRA) for Unit 6 of the Kashiwazaki Kariwa Nuclear Power Plants (ABWR, 1,356 MWe). The revised application sets January 20, 2026, as the planned reactor startup date and February 26, 2026, as the target date for the start of commercial operation. TEPCO also disclosed that it had filed a similar amendment for Unit 7 (ABWR, 1,356 MWe), as shared facilities must be used when Unit 6 begins operation.

For both units, TEPCO submitted pre-operational inspection applications in September 2024 to undergo inspections by the NRA, followed by amendments in November of the same year reflecting construction schedules up to fuel loading. Fuel loading was carried out on June 21, 2025, after which post-fuel-loading integrity checks-covering water and gas leakage, control rod operability, and emergency core cooling system performance-along with pre-operational inspections conducted by the operator were completed by October 28, 2025. Technical preparations for reactor startup had therefore been completed.

On December 22, the Niigata Prefectural Assembly passed a resolution expressing confidence in Governor Hideyo Hanazumi, who had indicated his acceptance of the restart of Units 6 and 7 at the Kashiwazaki Kariwa site. The following day, Governor Hanazumi formally conveyed local consent for the restart to the Minister of Economy, Trade and Industry, bringing discussions toward restart into their final stage.

Once approval for test operation is granted by the NRA, TEPCO plans to proceed with equipment integrity verification, including pre-operational inspections conducted after reactor startup.

The main steps from reactor startup to the commencement of commercial operation are as follows.

First, the reactor is scheduled to be started on January 20, 2026. Control rods will be withdrawn to initiate nuclear fission, after which reactor output will be gradually increased. During this process, TEPCO will confirm that reactor cooling systems, control systems, and other components function as designed.

Next, the turbine will be started using heat generated by the reactor, and generator output will be raised step by step to approximately 50%. At this point, an intermediate shutdown will be carried out to conduct detailed inspections of the condition of major equipment. Following the intermediate shutdown, the reactor will be restarted, output will again be increased, the turbine restarted, and generator output raised further, ultimately bringing the reactor to approximately 100% of rated thermal output.

After reaching rated output, an overall load performance test will be conducted. Upon completion of these steps, TEPCO plans to commence commercial operation on February 26, 2026.

TEPCO stated that it will "continue to place the highest priority on safety and steadily proceed with each step while sincerely responding to inspections by the Nuclear Regulation Authority."