The Hiroshima High Court will reiterate its decision on the 18th regarding the decision of the Hiroshima High Court to dispose of the provisional disposition last year, which did not allow the operation of Shikoku Electric Power Ikata Nuclear Power Station Unit 3 in Ehime Prefecture.

Due to the decision, Ikata Nuclear Power Plant Unit 3 remains inoperable, and the court's decision is drawing attention.

Regarding Ikata Nuclear Power Plant Unit 3 in Ehime Prefecture, the Hiroshima High Court approved the complaints of three residents of the island in the southeastern part of Yamaguchi Prefecture in January last year, and said that there was a specific danger due to an earthquake or volcanic eruption, and started driving. We have issued a decision on provisional disposition that we do not approve.



In response to Shikoku Electric Power's objection to the decision, a procedure was carried out to hear opinions from both Shikoku Electric Power and residents under another presiding judge of the Hiroshima High Court, and an active fault was found near the site of the nuclear power plant. There was a dispute over whether or not there was a huge eruption on Mt. Aso in Kumamoto prefecture, which is about 130 kilometers away.



In this, the Shikoku Electric Power Company insisted, "There is no active fault near the site of the nuclear power plant, and there is no specific danger because the occurrence of a huge eruption is not imminent."



On the other hand, the residents insisted, "It is clear that there is an active fault near the site of the nuclear power plant, and it is difficult to judge that a huge eruption will not occur at the current scientific level."



The Hiroshima High Court will make a decision on this on the afternoon of the 18th.



Ikata Nuclear Power Plant Unit 3 has been inoperable due to last year's decision, and it will be interesting to see how the court decides.

History of Ikata Nuclear Power Plant Unit 3

Shikoku Electric Power's Ikata Nuclear Power Station Unit 3 was shut down for regular inspections one month after the accident at the Fukushima Daiichi Nuclear Power Plant 10 years ago.



After that, a new regulatory standard was established based on the lessons learned from the accident, and passed the examination by the Nuclear Regulation Authority in 2015, six years ago.



Then, with the consent of Ehime Prefecture and the local Ikata Town, it restarted in 2016, more than five years after the operation was stopped.



Under these circumstances, residents of Ehime, Hiroshima, Oita, and Yamaguchi, who live in the area around the nuclear power plant, filed a series of provisional disposition requests for suspension of operation in their respective courts.



Of these, the Hiroshima High Court issued a decision in December 2017 to point out the danger of an eruption of Mt. Aso in Kumamoto Prefecture and order the suspension of operation for a limited time, and Ikata Nuclear Power Plant Unit 3 became inoperable. ..



As a result of Shikoku Electric Power's objection, in September 2018, another presiding judge of the Hiroshima High Court canceled the decision and operated, saying that "the possibility of a huge eruption cannot be said to be grounded." I admitted.



In response to this, Shikoku Electric Power restarted Ikata Nuclear Power Plant Unit 3 and resumed commercial operation.



Then, in January last year, the Hiroshima High Court again said that there was a specific danger that the lives and bodies of the residents would be seriously damaged by the earthquake and volcanic eruption in response to the petition for provisional disposition made by the residents of Yamaguchi Prefecture. , Did not allow driving.



Regarding the safety of Ikata Nuclear Power Plant Unit 3, different judicial decisions have been made one after another, and the operation has been stopped and restarted repeatedly.



There are also Units 1 and 2 at the Ikata Nuclear Power Plant, but work is underway to decommission them.

The main issue of provisional disposition is

In the provisional disposition of Ikata Nuclear Power Plant Unit 3, safety against earthquakes and volcanic eruptions caused by active faults became a major issue.



The first issue is whether the magnitude of the shaking assumed by Shikoku Electric Power Co., Inc. is appropriate when an earthquake occurs in the "Median Tectonic Line Fault Zone" of the active fault extending from Kinki through Shikoku to the east of Kyushu. ..



In January last year, the Hiroshima High Court decided not to allow operation, and there is a geological structural boundary within 2 km from the site closer to the nuclear power plant than the known active fault, which may be an active fault. I decided that I couldn't deny it.



He pointed out that "Shikoku Electric Power Co., Inc. has not evaluated the magnitude of the shaking of the earthquake when the epicenter is extremely close to the site, and the NRA's judgment that this is not a problem is incorrect."



On the other hand, Shikoku Electric Power Co., Inc. stated that the Median Tectonic Line fault zone is about 8 km north of the nuclear power plant and that there would be no significant impact even if an earthquake occurs. The boundaries of the nearby geological structure are not active faults and there is no need to assess the magnitude of the tremor. "



On the other hand, the residents said that there is an active fault at a position about 600 meters from the nuclear power plant based on the indication by a geologist, "The survey conducted by Shikoku Electric Power Co., Inc. is insufficient, and the active fault is close to the nuclear power plant. It is a mistake not to evaluate the shaking of the earthquake assuming that there is. "



The second issue is how far we can expect the impact of a huge eruption on Mt. Aso in Kumamoto Prefecture, which is located about 130 km west of the Ikata Nuclear Power Plant.



Last January, the Hiroshima High Court pointed out that it is difficult to accurately predict the timing and scale of an eruption at the current scientific level, and that the impact of an eruption should be similar to that of a catastrophic eruption.



He pointed out, "Given the eruption that does not lead to a catastrophic eruption, the amount of volcanic ejecta assumed by Shikoku Electric Power is too small, and the NRA's decision on this premise is unreasonable."



On the other hand, according to a survey by many experts, Shikoku Electric Power Co., Inc. could not confirm the state where magma that would cause a huge eruption was accumulated in the basement of Mt. The court's decision to consider eruptions that do not lead to a target eruption is irrational. "



On the other hand, the residents pointed out that "the assumption of Shikoku Electric Power is unreasonable in that it excludes eruptions of a scale similar to a catastrophic eruption and considers an eruption of a much smaller scale." There is a risk of accidents because the safety function cannot be maintained for volcanic ash exceeding the amount. "