A Japanese court has decided to allow five ageing nuclear reactors to continue operating at NPPs run by Kansai Electric Power Co, dismissing local residents' safety concerns that led to demands for suspensions. The Fukui District Court denied injunctions to halt unit 3 at the Mihama NPP units 1-4 at the Takahama plant, both in Fukui Prefecture. The reactors began commercial operations between 1974 and 1985. Presiding Judge Yasushi Kato said the court did not find any reasons to believe the reactors would encounter problems and endanger residents.

The reactors are operating in line with the stricter standards implemented after the Fukushima Daiichi nuclear accident in 2011, and factors unique to the locations of the reactors have been appropriately assessed, Kato said. The safety measures necessary for operating such ageing facilities have been taken, he added.

Mihama 3, which started operation in 1976 in 2021 became first nuclear unit in Japan to operate beyond the government-mandated 40-year service period, introduced under the post-Fukushima regulatory standards. The service period for reactors was subsequently extended to 60 years or more in 2023 provided the necessary safety upgrades were completed. The law will come into effect in June 2025.Nine Fukui residents who filed the complaint about Mihama 3 said in a statement that the ruling was "unjust”.

Takahama's reactors began operations between 1974 and 1985. Units 1&2 were restarted in 2023 for the first time since the 2011 disaster. Takahama 1, the oldest operating reactor in Japan, was commissioned in November 1974. The Nuclear Regulation Authority (NRA) has approved extension of the reactor's operating life to 60 years, but Kansai Electric must also obtain the NRA approval of the submitted documents, including soundness assessments, before the reactor reaches its 50th anniversary.

Before the March 2011 accident at the Fukushima Daiichi NPP, Japan had 54 reactors in operation providing around 30% of its electricity. However, within 14 months of the accident, all the plants were closed pending regulatory change in line with more stringent safety checks and regulations. Subsequently a number of nuclear units were closed permanently. To date, 12 of the remaining 33 operable reactors have cleared inspections confirming they meet the new regulatory safety standards and have resumed operation. Another 17 have applied to restart. The restarted plants are Sendai 1&2, Genkai 3&4, Ikata 3, Mihama 3, Ohi 3&4 and Takahama 1-4.

Japan’s government is now seeking to bringing back nuclear power as a key energy source to support its energy security and reduce dependence on imported fossil fuels. Japan, which needs to import about 90% of its energy requirements, in December 2022 adopted a new policy to encourage nuclear energy, allowing reactors to operate for 60 years. Subsequently, a panel of experts under the Japanese Ministry of Industry decided that Japan should allow the development of new nuclear reactors and also permit available reactors to operate beyond the limit of 60 years.

Image: The Mihama nuclear power plant in Fukui Prefecture