The Mito District Court will hand down a ruling on the 18th in a trial requesting that residents not restart the Tokai No. 2 Nuclear Power Station in Tokai Village, Ibaraki Prefecture, saying that it may cause a serious accident due to a huge earthquake. ..



It will be interesting to see how the court will decide to restart the nuclear power plant, which has the largest number of 940,000 people living within 30 kilometers.

Regarding the Tokai No. 2 nuclear power plant of Japan Atomic Power Company in Tokai Village, Ibaraki Prefecture, 224 residents of Ibaraki and Tokyo have filed a complaint not to restart because of the possibility of causing a serious accident due to a huge earthquake. ..



In the trial held for more than eight years, the setting of the largest earthquake tremor "standard ground motion" expected around the nuclear power plant and the seismic resistance of the reactor pressure vessel became issues, and the plaintiff side had a safety problem. While claiming that there was, Japan Atomic Power Company claimed that sufficient safety measures were taken.



The Tokai No. 2 Nuclear Power Plant has been shut down since the Great East Japan Earthquake, but Japan Atomic Power Company is proceeding with countermeasures such as the construction of seawalls based on new regulatory standards with the aim of restarting.



The ruling is scheduled to be handed down at 2:30 pm on the 18th, and it will be interesting to see how the court will decide to restart the nuclear power plant, which has the largest number of nuclear power plants in the country, 940,000, within 30 km.

What is Tokai No. 2 Nuclear Power Plant?

The Tokai No. 2 Nuclear Power Station, located in Tokai Village, Ibaraki Prefecture, is the only nuclear power plant in the Tokyo metropolitan area located approximately 110 kilometers from the city center.



Operated by Japan Atomic Power Company = Japan Atomic Power Company, with an output of 1.1 million kilowatts, it began operation in November 1978 as Japan's first large-scale nuclear power plant exceeding 1 million kilowatts.



Like the Fukushima Daiichi Nuclear Power Plant, it is a type called "boiling water reactor" that directly turns a turbine using steam generated in a nuclear reactor to generate electricity, and the generated power was sold to TEPCO and Tohoku Electric Power. ..



Ten years ago, in the Great East Japan Earthquake of 2011, a tsunami with a maximum height of 5.4 meters was observed, and some of the equipment for cooling the reactor was damaged.



The reactor automatically shut down due to the shaking of the earthquake and has not been in operation since then.



In September 2018, we passed the examination of the new regulatory standards that are the premise of restarting after the accident at the Fukushima Daiichi nuclear power plant.



In November of this year, the extension of the operation period was also approved, and it is possible to operate until November 20th of Reiwa at the longest.



Japan Atomic Power Company is aiming for restart, and is proceeding with countermeasure construction such as construction of a seawall with a height of 20 meters and a length of 1.7 km based on new regulatory standards, and will be completed in December next year. It is expected to do.



In addition, we plan to spend about 61 billion yen to complete facilities for anti-terrorism measures such as aircraft, which are required to be installed under the new regulatory standards, by October 5th, two years later.



TEPCO, the largest shareholder and sales destination of electricity, will support the large amount of costs required for countermeasure construction and the installation of anti-terrorism facilities.



On the other hand, in order to restart, Japan Atomic Power Company needs to obtain prior consent from six surrounding cities and villages including Ibaraki Prefecture and Tokai Village, but it is unclear whether it will be possible to obtain consent and the specific outlook for restarting. Is not standing.

History of the trial

In July 2012, when the accident at the Fukushima Daiichi nuclear power plant occurred, 266 residents from Ibaraki, Tokyo, Chiba, etc. filed a trial in the Mito District Court.



As the trials took longer, some plaintiffs died one after another, eventually reaching 224.



Witnesses of both the plaintiff and the defendant appeared in court last year to express their opinions on the standard ground motion and the seismic resistance of the reactor pressure vessel, which are the largest earthquake tremors expected around the nuclear power plant, which were the main issues. It was.



Then, in July last year, the plaintiff made closing arguments and concluded the case.



The plaintiff initially requested the government to revoke the permission to install the reactor, but withdrew the complaint against the government in November 2018 to prevent the trial from being prolonged.

The main issue is

At the trial, the main issues were the setting of the largest earthquake tremor "standard ground motion" expected around the nuclear power plant and the seismic resistance of the reactor pressure vessel.

Issue 1 Standard ground motion

The standard ground motion is expressed in the unit of acceleration "gal", and the operator, Japan Atomic Power Company, has set the standard ground motion of the Tokai No. 2 nuclear power plant as "1009 gal".



The National Nuclear Regulatory Commission acknowledged that due consideration had been made, and the Tokai No. 2 Nuclear Power Plant passed the examination of new regulatory standards that are a prerequisite for restarting in 2018.



Regarding this, the plaintiff assumes that a large seismic wave "strong ground motion pulse" with a period of about 1 to 2 seconds, which may cause great damage to equipment such as the nuclear power plant building and the reactor pressure vessel, occurs off the coast of Ibaraki Prefecture. He claimed that the standard seismic motion would be "2000 gal" and that the value set by Japan Atomic Power Company did not cover the seismic motion that hit the Tokai No. 2 nuclear power plant.



In addition, when calculating the standard ground motion from the average value of the magnitudes of earthquakes that occurred in the past, we did not fully consider that there are earthquakes that are far from the average value, that is, there is "variation", and Japan It is said that there is a risk of stronger shaking than expected on the power source side.



He also argued that the new regulatory standards of the country were "not necessarily sufficient", saying that they did not sufficiently show the specific rules for calculating the standard ground motion.



On the other hand, Japan Atomic Power Company has not established the calculation method used by the plaintiff as a method for predicting ground motion, and has formulated the standard ground motion based on the latest knowledge and data including new regulatory standards. He argued that sufficient safety measures were taken.

Issue 2 Earthquake resistance

The trial also contested the seismic resistance of reactor pressure vessels.



The plaintiff said that the device called "stabilizer" that prevents the pressure vessel from tipping over in the event of an earthquake will be damaged if an earthquake that exceeds the standard ground motion set by Japan Atomic Power Company occurs, and the pressure vessel will tip over, causing a core meltdown, etc. Claimed that a serious accident could occur.



In response, Japan Atomic Power Company argued that it has confirmed that the "stabilizer" has sufficient seismic margin and can maintain safety functions.

Issue 3 Tsunami Assumption

There was also a dispute over the height of the tsunami and the assumption of damage.



Japan Atomic Power Company has set the expected tsunami height to 17.1 meters and has passed the new regulatory standards.



In this regard, plaintiffs argued that the assumptions were too small to cover the tsunami that could hit the nuclear power plant, and that huge drifting objects such as large vessels could hit seawalls and buildings.



In response, Japan Atomic Power Company argued that it had set tsunami assumptions based on new knowledge and that it was unlikely that large vessels would reach the power plant.

Issue 4 Volcano

Regarding measures against volcanoes, the plaintiff insisted that if more volcanic ash than expected was accumulated on the premises, the nuclear power plant would lose its cooling function and the nuclear fuel would melt and melt down, while Japan Atomic Power Company took measures. He argued that he had taken steps to confirm that safety could be ensured.

Challenges for restarting

The restart of the Tokai No. 2 nuclear power plant is premised on the completion of countermeasure construction based on the new national regulatory standards, and there are two issues: the consent of the local government and the formulation of a wide-area evacuation plan.

Issue 1 Consent of local government

In order to restart the Tokai No. 2 Nuclear Power Plant, the operator, Japan Atomic Power Company, must obtain the consent of the local government based on the agreement concluded with the local government.



Originally, consent was obtained only for Tokai Village and Ibaraki Prefecture, where the Tokai No. 2 Nuclear Power Plant is located, but in 2018 Japan Atomic Power Company restarted between six cities and villages around the nuclear power plant, including Tokai Village. At that time, we signed the only agreement in the whole country to "obtain substantial prior consent".



These six cities and villages are cautious about whether or not to restart the operation, saying that they will make a decision after listening to the opinions of the residents, and it is unclear whether or not they will be able to obtain their consent.



Japan Atomic Power Company and the six municipalities are supposed to establish a council to discuss restarting operations, but the council has not yet been established and discussions have not progressed.



In addition, Ibaraki Prefecture uniquely providing a professional conference, we have to verify the issues of the original to the more than 200 comments from committee members and residents about the safety, but when to prospect to complete does not stand.

Issue 2 Wide area evacuation plan

Furthermore, it is difficult to formulate a wide-area evacuation plan in case of a serious accident at the nuclear power plant.



Wide-area evacuation plans are obligatory for local governments to be formulated by the national nuclear disaster countermeasure guidelines.



It is not a condition that it is formulated prior to restarting, but all nuclear power plants that have been restarted so far are formulated before restarting.



It is obligatory to formulate a plan in the area within 30 km from the nuclear power plant, and in the case of the Tokai No. 2 nuclear power plant, 14 municipalities including the entire area of ​​Mito city are included, and 940,000 people, the largest number of nuclear power plants in Japan, live here. I am.



For this reason, securing evacuation means for residents and measures against traffic congestion are major issues in formulating effective plans.



So far, only five municipalities have completed the formulation of plans, including Kasama City, Hitachiota City, and Hitachiomiya City.