Court ruling clears way for Ikata 3 restart

Ikata 3 - a 846 MWe pressurised water reactor - was given approval by the Nuclear Regulatory Authority 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.

Four residents from Matsuyama and Hiroshima filed a request for a temporary injunction against the unit's operation with the Hiroshima District Court on 11 March 2016, the fifth anniversary of the Fukushima Daiichi accident. The plaintiffs claimed that Shikoku had underestimated the potential size of an earthquake that could strike the plant and the risks posed by a volcano some 130km away. The operator has claimed there is a low possibility of Mount Aso experiencing a large-scale eruption while the reactor is in operation.

However, on 30 March 2017, the court ruled that Shikoku had used reliable measures in calculating the basic earthquake ground motion at the site and rejected the petition. The following month, the plaintiffs appealed the decision in the Hiroshima High Court.

In December 2017, that court overruled the district court's decision and ordered the suspension of Ikata 3's operation. Ikata 3 had been taken offline in October 2017 for maintenance and periodic inspections and was scheduled to restart on 22 January. The injunction was effective until the end of September. Shikoku described the high court's ruling as "extremely disappointing" and promptly filed an appeal against its decision. The plaintiffs filed a request in May with the high court to extend the injunction beyond the end of September.

In late-September, however, the court accepted Shikoku's appeal and cancelled the injunction, allowing the utility to begin the process of restarting the reactor.

In line with the high court decision, the Hiroshima District Court today rejected the call to extend the injunction.

Presiding Judge Takahiko Fujisawa was quoted by the Kyodo news agency as saying the possibility of a major eruption occurring at Mount Aso is "very low", adding that "there is no risk that needs to be removed immediately with the injunction."

The utility said it had received a "reasonable decision" from the court, which had accepted "the company's previous claims that the safety of unit 3 of the Ikata power plant is secured".

Shikoku plans to restart Ikata 3 on 27 October, with power generation expected from 30 October. Commercial operation of the reactor is set to resume on 28 November.