Court rejects lawsuit to stop Ikata nuclear reactor in western Japan

A district court on Thursday rejected a lawsuit seeking to halt the operation of a nuclear reactor in western Japan amid safety concerns, finding that the earthquake and volcano risk assessments conducted by the plant operator were reasonable.

In the ruling delivered by the Oita District Court regarding the operation of Shikoku Electric Power Co.'s No. 3 reactor at the Ikata nuclear power plant in Ehime Prefecture, Presiding Judge Maiko Takechi said the court does not see any "specific danger" that threatens the lives of the plaintiffs in Oita Prefecture.

The case was brought by 569 residents of Oita, located across the Seto Inland Sea from Ehime, who argued that the power company's measures against earthquakes and volcanic eruptions were insufficient.

The plaintiffs pointed to a possibility that there may be an active fault near the plant other than the Median Tectonic Line fault zone, which is one of the largest in Japan, and the company has not sufficiently studied the underground structure.

The residents are also concerned about the risk of a massive volcanic eruption at Mount Aso, which is about 130 km away.

Shikoku Electric has said its sonic prospecting has not shown the existence of an active fault near the plant, while dismissing the need for a three-dimensional survey to look into the underground structure as requested by the plaintiffs.

The utility has also played down concerns that pyroclastic flows would reach the reactor even in the event of a catastrophic eruption of Mount Aso.

The case is among a series of similar lawsuits filed by residents in the prefectures of Oita, Ehime, Hiroshima and Yamaguchi against the reactor, the sole operating reactor at the Ikata plant.

The plaintiffs plan to file an appeal.

(Cover: An area of Mount Aso in Kumamoto Prefecture, Japan, November 9, 2022. /CFP)