Ohi Nuclear Power Plant Injunction Case

Filed in 2013, this case involved local residents seeking a permanent injunction to halt the operation of Units 3 and 4 at the Ohi Nuclear Power Plant in Fukui Prefecture. The plaintiffs argued that Kansai Electric Power Company’s safety measures were insufficient to protect against severe accidents, particularly given the plant's proximity to active seismic faults. They claimed that a major earthquake or tsunami could lead to a catastrophic meltdown similar to the Fukushima Daiichi disaster, violating their personal rights to life and safety. The court meticulously examined the adequacy of the defendant’s seismic design basis and severe accident countermeasures under the new regulatory regime.

In May 2014, the Fukui District Court issued a landmark ruling granting the permanent injunction, ordering Kansai Electric to shut down and not restart Ohi Units 3 and 4. The court found that the defendant's earthquake safety evaluations were unreasonable and that a realistic risk of a severe accident capable of destroying the reactors existed, thereby infringing on the plaintiffs' personal rights.

The central dispute was whether the nuclear plant's safety design basis, especially the seismic ground motion assumptions, was scientifically robust enough to guarantee the absolute safety of the reactors. The judgment hinged on the judicial evaluation of technical risk assessments and whether the new post-Fukushima regulatory standards constituted a sufficient guarantee of personal rights against catastrophic harm.

The ruling sent shockwaves through Japan's nuclear industry and legal circles. It marked the first time a Japanese court had ordered a halt to an operating nuclear power plant with such a definitive condemnation of its safety logic post-Fukushima. It emboldened similar anti-nuclear lawsuits across the country, profoundly challenging the government's push for reactor restarts and reinforcing public skepticism regarding the effectiveness of new regulatory safety reviews.