FUKUOKA (Kyodo) -- A district court said Monday it had found no illegality in safety clearance granted for two nuclear reactors in southwestern Japan that restarted after the 2011 Fukushima crisis, dismissing a demand by local residents and others seeking retraction of the permission.
A total of 33 plaintiffs filed the lawsuit over a license issued by regulators for design changes to the Nos. 1 and 2 units at Kyushu Electric Power Co.'s Sendai nuclear power plant in Kagoshima Prefecture, under tougher post-Fukushima safety regulations.
The two units were the first to restart among the commercial reactors that went offline in the wake of the nuclear disaster. The plaintiffs argued regulators gave the green light without sufficiently assessing the potential risk of eruptions at nearby Mt. Aso in Kumamoto Prefecture and four other volcanoes.
But, in the first ruling of its kind, the Fukuoka District Court concluded the license issued by the Nuclear Regulation Authority was not illegal.
"Japanese laws on nuclear power do not go so far as requiring (regulators) to consider the impact of a catastrophic volcanic eruption that is impossible to predict and highly unlikely to occur," Presiding Judge Moriharu Kurasawa said.
But Kurasawa acknowledged there were some "doubts" over the NRA's volcanic risk assessment standard, given that methodology to accurately assess volcanic activity is yet to be established.
The plaintiffs, from a total of 10 prefectures, are considering appealing the ruling. Kyushu Electric said it viewed the ruling as "appropriate" and will continue to work to ensure the safety of the reactors.
During the trial, authorities said the rules were rational based on the latest analysis and there was nothing wrong with the approval process.
The plaintiffs, meanwhile, argued it is difficult to predict exactly when an eruption could occur and how big it could be, and the current safety standards on volcanoes underestimate their impact.
"It is regrettable," Ryoko Torihara, a 70-year-old plaintiff from Kagoshima Prefecture, said after the ruling, adding, "The lessons of the nuclear accident (in Fukushima) have not been learned."
Another plaintiff said, "The frequency of a catastrophic eruption may be low, but it could happen tomorrow. I'm very disappointed that the ruling appears to be just following (what) the state (wants to do)."
While the government is aiming to bring reactors back online after the triple reactor core meltdown at the Fukushima Daiichi complex led to a nationwide halt of nuclear plants, a number of lawsuits have been filed in the hope of stopping the drive.
The Nos. 1 and 2 reactors at the Sendai plant were rebooted in August and October 2015, respectively, after securing the license in September 2014.
A suit demanding an injunction to halt the Sendai reactors was rejected by the Kagoshima District Court in April 2015, a decision upheld by the Miyazaki branch of the Fukuoka High Court in April 2016.
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 planned 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 Mt. Aso, around 130 kilometers away.
But the court later accepted an appeal by the utility to reactivate the reactor, saying worries over a volcanic eruption damaging the unit were "groundless."
The Saga District Court in March 2018 rejected local residents' demand to suspend the planned restart of two reactors at Kyushu Electric's Genkai plant in Saga Prefecture due to the risk of a volcanic eruption in the region.