Japan court denies request to revoke extension of aging nuclear units

The Nagoya District Court ruled in favor of the continued operation of the Nos. 1 and 2 reactors at the Takahama nuclear plant and the No. 3 unit at the Mihama plant, all in Fukui Prefecture and run by Kansai Electric Power Co., in the first judicial decision in lawsuits seeking revocation of approval for extending the operation of reactors.

All three reactors started operating in the 1970s. They cleared stricter safety regulations implemented following the Fukushima nuclear accident triggered by the March 2011 earthquake and tsunami disaster and were granted approval in 2016 to extend operations for up to 20 years beyond the limit.

The latest suit was filed in 2016, with the plaintiffs, including residents of Fukui and Aichi prefectures, arguing that the Nuclear Regulation Authority erroneously assessed the safety of the reactors.

They said the standard used to check the aging of the reactors' pressure vessels was unreasonable and that the containers face the risk of collapsing if cooled rapidly during an emergency.

The central government said the regulator's assessment was appropriate, with standards compiled by many experts and highly credible.

Following the nuclear accident, the government introduced rules mandating that nuclear units can operate for up to 40 years, with extensions to 60 years possible pending approval by regulators.

But as the government considers nuclear power vital in the resource-poor country's energy mix, the parliament enacted in 2023 a bill to introduce a new system allowing the country's nuclear reactors to operate beyond the 60-year limit, with the introduction slated in June this year.

Under the new rules, nuclear reactors may be granted additional operating years by exempting their offline periods from their total service time, provided the periods are due to reasons beyond a utility's control, such as a safety review or court-ordered suspension.