Photo/IllutrationLawyers hold up signs proclaiming victory in the case at the Hiroshima High Court on Jan. 17. (Koichi Ueda)

  • Photo/Illustraion

HIROSHIMA--The high court here Jan. 17 ordered a halt to operations of the No. 3 reactor at the Ikata nuclear power plant in Ehime Prefecture due to fears it is located near an active fault.

The temporary injunction issued by the Hiroshima High Court does not allow for operations of the reactor to resume unless the Supreme Court hands down a ruling reversing it.

The No. 3 reactor at the plant, which is located in Ikata in the prefecture and operated by Shikoku Electric Power Co., is currently offline for regular inspections.

Three residents living on an island in the Seto Inland Sea within a roughly 50-kilometer radius of the plant had filed a request for a temporary injunction, but the Iwakuni branch of the Yamaguchi District Court rejected it in March 2019. The plaintiffs then appealed the decision to the Hiroshima High Court.

They argued that an active fault linked to the median tectonic line--Japan's longest fault system--may exist about 600 meters off the coast from the nuclear plant.

Considering the proximity, they said the expected maximum strength of an earthquake in the area, used in the facility's quake-resistance design, could be two to three times the utility's standard.

During the high court trial, Shikoku Electric argued that sonic wave tests could not confirm the existence of active faults near the Ikata plant.

The plaintiffs also pointed out the risk of pyroclastic flows in the event of a massive eruption at Mount Aso in Kumamoto Prefecture, about 130 kilometers away. Their safety concerns were further fueled by the utility's lack of a detailed accident evacuation plan. In the event of a disaster, they said it would be difficult to reach the main island of Honshu.

Shikoku Electric argued there was slim possibility of such a major eruption while the Ikata plant was operating. It also claimed to have taken adequate measures to prevent a catastrophic accident at the facility.

Following the high court ruling, Satoru Katsuno, chairman of the Federation of Electric Power Companies, said at a Jan. 17 news conference in Tokyo: "(The ruling) is very regrettable. With few energy resources in Japan, nuclear energy has a major role to play in providing a stable supply of electricity and as a way to deal with global warming."

"Making every effort to meet new safety standards, we will also do our utmost to improve explanations to those living in host municipalities and general society," he added.

It is the second time that the No. 3 reactor has been ordered offline. An order to suspend operations was issued in a separate case in December 2017 at the Hiroshima High Court.

(This article was written by Toshinari Takahashi, Takashi Endo and Kuniaki Nishio.)