NRA of Japan Approves Operation Beyond 30 Years for Ohi 3 and 4

On June 26, the Nuclear Regulation Authority (NRA) of Japan approved long-term facility management plans for the Ohi-3 and -4 Nuclear Power Plants (NPPs)-both PWRs with an electrical output of 1,180MW each-owned and operated by the Kansai Electric Power Co. (Kansai EP) in Fukui Prefecture.

Under a new act for the partial revision of the Electricity Business Act and other acts for establishing electricity supply systems to realize a decarbonized society (known collectively as the GX Decarbonization Power Supply Bill)-which includes the tightened regulation of aging NPPs-nuclear operators in Japan are required to submit a management plan to extend the operation of NPPs to more than 30 years from their actual entry into service. Ohi-3 and -4 are the first cases since the enactment of the act.

From the perspective of the regulator, the Law for the Regulation of Nuclear Source Material, Nuclear Fuel Material and Reactors (the Reactor Regulation Law), as of summer 2023, requires nuclear operators in Japan to make a technical evaluation of NPP deterioration after 30 years of operation. Furthermore, the same law requires the operators of such NPPs to issue a plan every ten years thereafter to manage any deterioration found and to obtain approval from the NRA.

From the perspective of nuclear operators in Japan, the Electricity Business Law maintains the current principle of maximum 60-year operating lifetimes, but the calculations of operating lifetimes will not include periods of suspension in a unit's history due to unforeseeable reasons on the part of the operator.

The GX Decarbonization Power Supply Bill―the previously mentioned revision package―will not come fully into effect until June 2025, for which preparations are being made. Kansai EP had been required to obtain approval from the NRA under the new law for its long-term facility management plans for the units, given that the Ohi-3 and -4 NPPs entered service respectively in December 1991 and February 1993, and given that they have been operating more than three decades. In December 2023, the power company submitted those applications.

With the approvals, Kansai EP released the following comment: "We will endeavor to enhance the safety and reliability of the plants by actively acquiring the latest domestic and overseas knowledge and information, and by reflecting them in plant designs and the maintenance of facilities."