Takahama-1 Resumes Commercial Operation as Second NPP in Japan to Operate Beyond 40 Years

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At 3:00 p.m. on August 2, Takahama-1 (PWR, 826 MW), owned and operated by the Kansai Electric Power Co. (Kansai EP), resumed commercial operation after a hiatus of twelve and half years. It is the second nuclear power plant (NPP) in Japan to remain in service beyond 40 years, following Kansai EP’s Mihama-3, which had been restarted in June 2021 under the new regulatory standards, and which resumed commercial operation that July. Takahama-1 is the 11th nuclear power plant (NPP) to clear new regulatory standards and resume operation.

Construction of Takahama-1 was launched in 1969, in the middle of Japan’s period of high economic growth, and made its debut on November 14, 1974, as the nation’s eighth NPP, and the third for Kansai EP, joining the company’s Mihama-1 and -2 units. Its output of 826MW was the highest in the country at that time. A year later, on November 14, 1975, the Takahama-2 (PWR, also 826MW) also began commercial operation. Together, Takahama-1 and -2 were the forerunners of Kansai-EP’s later, larger NPPs: Mihama-3 and Ohi-1 and -2.

Operation of Takahama-1 was suspended in January 2011 in association with its periodic inspection. In the wake of the giant earthquake of March 2011, compatibility examinations of Takahama-1, Takahama-2 and Mihama-3 started in March 2015 under the new regulatory standards. In April 2016, permission was granted to amend the reactor installations (basic design approvals) at Takahama-1 and Takahama-2. By April 2021, local consent had been obtained to restart both units.

Meanwhile, the deadlines expired on June 9, 2021, for the installation of facilities for responding to specific severe accidents at Takahama-1 and -2, required under the new regulatory standards. (Such facilities include bunkered emergency control rooms and buildings, termed “specific safety facilities;” installation deadlines were five years after the approval of designs and work plans for the main bodies of the plants.) Ultimately, the specific safety facilities at Takahama-1 began operation on July 14, 2023, including adjustments for suspended operations, and the reactor was restarted on July 28.

From now on, Takahama-1 is expected to return to commercial service on August 28, via an integrated performance test that is normally the final step in a periodic inspection.

JAIF President ARAI Shiro released a comment concerning Takahama-1’s restart. Referring to previous NPP restarts by Kansai EP, he said, “Continuing safe, stable operations have been very important in deepening the confidence of the public nationwide, including local residents.” He said that he expected work would be conducted with safety as the top priority toward restarting both Takahama-2 and boiling water reactor (BWR) plants.