Second injunction keeps Ikata reactor offline

Ikata 3 - a 846 MWe pressurised water reactor - was given approval by the Nuclear Regulatory Authority (NRA) to resume operation in April 2016, having been idle since being taken offline for a periodic inspection in April 2011. Shikoku declared the unit back in commercial operation on 7 September 2016. The reactor has been in an outage for maintenance and inspections since last December and is scheduled to restart on 27 April.

Three residents of nearby Yamaguchi Prefecture brought an action to the Iwakuni branch of the Yamaguchi District Court calling for operation of the unit to be suspended. They claimed the NRA's regulations were inadequate and raised safety concerns in the event that the Mount Aso volcano, some 130km away, should erupt. However, that court ruled on 15 March last year that Ikata 3 could continue operating after concluding the NRA's regulations were appropriate and that there was a low probability of the volcano erupting. Two weeks later, the residents launched an appeal to the District Court's decision in the Hiroshima High Court.

The High Court has now ruled in favour of the residents. Presiding Judge Kazutake Mori said the presence of an active fault near the Ikata plant could not be ruled out as Shikoku had not conducted a full survey of the area. He also claimed the impact of a possible eruption of Mount Aso had been underestimated. In addition, the judge also questioned whether permission to resume operation of Ikata 3 had mistakenly been granted to Shikoku by the NRA.

"So far, our company has carefully asserted to the court, by taking into account the latest scientific knowledge, that the Ikata plant has enough reliability for its safety against eruptions of the volcano or earthquakes," Shikoku said in a statement. The injunction means the reactor is unlikely to be restarted as planned in April. Shikoku said the decision was "extremely regrettable and totally unacceptable". The utility says it will "promptly" file an appeal so that the injunction can be revoked as soon as possible.

In a different case, the Hiroshima High Court in December 2017 overruled a district court's decision to allow Ikata 3 to operate and ordered the suspension of its operation. However, the same court overruled the decision in September 2018 on appeal.

Satoru Katsuno, president of the Federation of Electric Power Companies, said in a statement today that the High Court's decision to issue an injunction was "very unfortunate". He noted that, in Japan, where energy resources are scarce, nuclear power should continue to play a major role in providing a stable power supply, as well as reducing energy bills and responding to global warming.

Prior to the Fukushima Daiichi accident in March 2011, Japan's nuclear generating capacity had provided around 30% of the country's electricity, but within 14 months of the accident its nuclear generation had been brought to a standstill pending regulatory change. A total of nine units (all pressurised water reactors) have restarted since 2015, while 17 reactors are in the process of gaining approval to restart.