Osaka High Court Backs Safety Approval for Oi N-Reactors

Osaka, May 28 (Jiji Press)–Osaka High Court on Thursday overturned a lower court ruling rejecting the Nuclear Regulation Authority’s safety approval for two reactors at Kansai Electric Power Co.’s Oi nuclear plant in Fukui Prefecture, central Japan. The high court thus found that the NRA’s safety approval for the No. 3 and No. 4 reactors at the nuclear plant in the town of Oi was reasonable. The court dismissed a petition by 116 plaintiffs, mainly local residents, seeking to cancel the approval on the grounds that the expected seismic shaking has been underestimated. The lawsuit focused on the interpretation of the variability clause in the NRA’s review guidelines, which stated that when establishing reference seismic motion, variability should be considered based on average values from past earthquake data. The clause was deleted from the guidelines in June 2022. Presiding Judge Masafumi Kawabata said that the clause could not be interpreted to mean that “it is necessary to consider whether a margin should be added to the average value.” Concluding that Kansai Electric had taken the variability into account by conservatively setting relevant data, the judge said that “no unreasonable aspects” could be found in the NRA’s judgment. In December 2020, Osaka District Court ruled that the NRA should have considered whether adding a margin to the average value was necessary but had failed to do so. The court revoked the approval for making alterations to the reactors under the country’s new safety standards. The district court said that there were unforgivable errors and omissions in the process of establishing the reference seismic motion in question. This ruling drew attention as the first judicial decision to revoke a permit for facility alterations based on the new regulatory standards, which were established to strengthen safety measures following the March 2011 triple reactor meltdown at Tokyo Electric Power Company Holdings Inc.’s tsunami-stricken Fukushima No. 1 plant in northeastern Japan. According to the lower court ruling, the NRA recognized in May 2017 that the Oi plant’s No. 3 and No. 4 reactors complied with the new safety standards. END [Copyright The Jiji Press, Ltd.]