A Japanese court has rejected a request to revoke the approval given by the Nuclear Regulation Authority (NRA) to extend the operation of three nuclear reactors in Fukui Prefecture beyond the service period limit of up to 40 years in principle.

The Nagoya District Court ruled in favour of the continued operation of Kansai Electric Power Co Takahama NPP units 1&2 and Mihama NPP unit 3. Presiding Judge Ryo Kenmochi said the court “does not recognise any unreasonable points in the Nuclear Regulation Authority’s assessments or conclusions.” The suit was filed in 2016, with the plaintiffs, including residents of Fukui and Aichi prefectures, arguing that NRA made errors in its assessments of the safety of the 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 plaintiffs said the standard used to check the ageing of the reactors’ pressure vessels was unreasonable and that they face the risk of collapsing if cooled rapidly during an emergency. The court rejected the argument, with Kenmochi saying that “validity including that of outside experts was confirmed.”