FUKUOKA – A district court said on Monday it found nothing illegal with a safety clearance granted to two reactors in Kyushu that were restarted after the 2011 Fukushima nuclear crisis, dismissing a demand for a retraction filed by plaintiffs who said it ignored the risk of volcanic eruptions.
The lawsuit was filed by 33 plaintiffs against a license authorizing design changes at reactors 1 and 2 at the Sendai nuclear power plant in Kagoshima Prefecture under tougher post-Fukushima safety regulations.
They were the first commercial reactors in the nation to be restarted after the crisis.
The plaintiffs argued the Nuclear Regulation Authority gave the green light without sufficiently assessing the potential risk of eruptions at nearby Mount Aso in Kumamoto Prefecture and four other volcanoes.
“Japanese laws on nuclear power do not go so far as to require that regulators consider the impact of a catastrophic volcanic eruption that is impossible to predict and highly unlikely to occur,” Judge Moriharu Kurasawa said.
But Kurasawa acknowledged there were “doubts” over the NRA’s standard for volcanic risk assessment, given no methodology exists for accurately assessing volcanic activity.
Kyushu Electric Power Co. described the ruling as “appropriate,” but the plaintiffs, who came from 10 prefectures, said they might appeal.
During the trial, authorities said that the rules were rational based on the latest analysis and that there was nothing wrong with the approval process.
The plaintiffs argued it is difficult to predict exactly when an eruption could occur and how big it could be, and said current safety standards underestimate their impact.
Volcanic hazards have been a major concern in regard to nuclear plant operations, with similar injunction requests filed elsewhere.
The Hiroshima High Court in December 2017 halted the restart of the No. 3 unit at Shikoku Electric Power Co.’s Ikata plant in Ehime Prefecture with a provisional injunction, citing the potential hazard from Mount Aso, around 130 km away.
But the court later accepted an appeal by the utility to reactivate it, saying worries over a volcanic eruption damaging the unit were “groundless.”