Supreme Court Ruling Rejects National Government Responsibility for Fukushima Evacuees

By Fukutake Kimiko (Head attorney for the Chiba Prefecture nuclear power plant victims lawsuit)

On June 17, 2022, the Supreme Court of Japan put an end to the four lawsuits filed by the evacuees of the Fukushima nuclear disaster in Fukushima, Gunma, Chiba, and Ehime prefectures. The sole point of dispute in these lawsuits was whether the Japanese government, which did not exert regulatory authority on the utility company, Tokyo Electric Power Company Holdings (TEPCO), for the implementation of measures against tsunamis, is liable to compensate for damages according to Paragraph 1, Article 1 of the Law Concerning State Liability for Compensation. The top court absolved the government.

The Fukushima nuclear disaster occurred when external power supply to the station was lost due to the earthquake, activating the emergency power supply system, which was then crippled by the tsunami that flooded the station above ground level. The loss of emergency power made reactor core cooling impossible, causing core meltdown and the discharge of huge volumes of radioactive substances. The plaintiffs claimed that, firstly, the loss of emergency power supply and consequent disaster had been foreseeable because it was possible to tell that tsunamis would flood the station above ground level, at which the reactor building and turbine building were situated, since the height and impact of tsunamis were calculated based on the Long-term Assessment released in 2002 by the governmental Headquarters for Earthquake Research Promotion. The second claim was that the disaster might have been prevented if the main buildings and main equipment rooms had been provided with measures to make them watertight, in addition to seawalls.

On the other hand, the government claimed that, firstly, the Long-term Assessment was not knowledge that could have been accepted as a just set of opinions sufficiently accurate and reliable to be incorporated into nuclear regulation, and that, secondly, even if tsunami countermeasures had been taken in response to the calculations based on the Long-term Assessment, tsunamis were calculated to arrive from the south, prompting a seawall to be built to the south of the station, such that the seawall would have had no effect against the tsunami experienced in this lawsuit, because the size and directions of the actual tsunami waves were completely different.


Supreme Court shies away from delivering a clear judgment about foreseeability

Concerning the tsunami calculations, the Supreme Court stated: “The fault model of the Meiji Sanriku Earthquake was applied to the areas closer to the Japan trench, such as the areas off the coast of Fukushima Prefecture. Many numerical calculations performed with the conditions of this fault model varied within the ranges that were deemed reasonable, using the design tsunami height evaluation methods available from tsunami evaluation technology. The highest possible tsunamis on the east face and southeast face of the station were calculated. The calculations included sufficient safety margins to meet the worst-case scenario foreseeable at that time. Thus, the calculations were reasonable.”

The Supreme Court did not examine the Long-term Assessment closely nor take it affirmatively; it stated that the calculations based on the Long-term Assessment were reasonable. However, the court did not clearly put aside the Long-term Assessment. The court statement can be understood to mean that the Assessment was reliable.

However, to determine foreseeability, it is not sufficient to consider only natural phenomena, namely, from what directions and at what heights tsunamis would arrive. What also needs to be considered is whether it was possible to foresee that, when a tsunami arrived above ground level, seawater could enter the buildings and rooms where critical facilities were placed through openings such as doors, pipe penetrations and air intakes, possibly submerging and crippling the emergency power supply. Sato Kazuo, former chairman of the Nuclear Safety Commission wrote in Logic of Nuclear Safety [in Japanese]: “Danger indicates the possibility of generating circumstances where human life, health, or assets may be significantly damaged.”

The Supreme Court wrote: “If the Minister of Economy, Trade and Industry had exerted regulatory authority, a seawall or similar construction designed to prevent the flooding of the station would have been installed to protect against tsunamis of the scale similar to those calculated in the Long-term Assessment.” It sounds as if the Supreme Court recognized the foreseeability of only natural phenomena.


Supreme Court adopts the seawall as the sole point of contention

The Supreme Court further stated, “Prior to the accident examined in this lawsuit, the basic countermeasure for the protection of nuclear facilities from tsunamis in this country was to build seawalls or the like to prevent seawater from entering the premises of the nuclear facilities in which safety equipment or the like are situated, to prepare against premise flooding due to tsunamis… Such an idea that installing seawalls or the like is not sufficient was not dominant, and in no other respects was the above-mentioned measure taken as insufficient as a tsunami countermeasure to protect nuclear facilities under the knowledge available before the accident examined in this lawsuit. Therefore, it is impossible to reasonably determine that the implementation of other measures was probable or that such other measures should have been taken in addition to the seawalls or the like designed to prevent the flooding of the premises examined in this lawsuit in the case of tsunamis of a scale similar to that of the accident, even if the Minister of Economy, Trade and Industry had exerted the above-mentioned regulatory authority before the accident.”

At the same time, however, a flooding accident had already been experienced at the Blayais Nuclear Power Plant in France. In response to the accident, watertight defense efforts were being made for critical equipment rooms in addition to the construction of seawalls. At Tokai Daini Nuclear Power Plant (Ibaraki Prefecture) and Hamaoka Nuclear Power Station (Shizuoka Prefecture), watertight defense efforts were already made for part of the buildings and critical equipment rooms. The safety philosophy of multiple protection, which demands multi-layer safety measures, was widely accepted around the world. A single measure is no longer regarded satisfactory for critical equipment such as the emergency power supply; multi-layer, diverse, and independent safety measures are demanded. The Supreme Court judgment is a sign of acceptance of the poor operation of the regulatory organization in Japan.


Supreme Court excessively emphasizes that the actual tsunami and earthquake were greater than the tsunami calculations

The Supreme Court stated, “The scale of earthquake predicted in the Long-term Assessment was around 8.2 in tsunami magnitude, and the flooding depth around the main buildings was estimated to be about 2.6 meters or less. The calculated tsunamis were higher than the station ground level on the southeast face, while on the east face, the calculated tsunamis did not exceed the ground level; namely, even if a tsunami of the same scale as calculated had arrived at the station examined in this lawsuit, it was not foreseen that seawater might enter the site from the east face.” The court examined in detail the tsunami experienced in this lawsuit, stating, “The epicentral area ranged about 450 kilometers north and south, and about 200 kilometers east and west. The maximum slippage was 50 meters or more. The magnitude of the earthquake experienced in this lawsuit was 9.0, and the tsunami magnitude was 9.1; the earthquake was the largest in Japan’s seismic monitoring history. With the arrival of the tsunami experienced in this lawsuit, volumes of seawater entered the station premises not only from the southeast face but also from the east face. The flooding depth near the main buildings due to the tsunami was a maximum of about 5.5 meters.” This finding is not wrong. However, it is not relevant to discuss the cause of the disaster based only on the scale of the earthquake (whether the tsunami magnitude was 8.2 or 9.1), the direction of tsunami arrival (whether from southeast or from east), or flooding depth (whether about 2.6 meters or less, or a maximum of about 5.5 meters). The real issue is whether tsunamis might arrive above the station ground level, whether seawater might enter the main buildings, whether emergency power supply might be flooded and crippled, and whether the danger of reactor core meltdown might be possible or probable. Because the tsunami calculations obtained based on the Long-term Assessment indicated that such a danger was possible, the danger did exist if the actual tsunami were as great as or greater than the calculations. As the dissenting opinion by Judge Miura points out, “In this lawsuit, the bottom line must not be overlooked while too much attention is paid to the scales and details of the earthquake or tsunami experienced in this lawsuit.”


Supreme Court judges that seawall installation is the only measure, taking account of tsunami calculations only

The Supreme Court wrote: “A seawall or the like designed to protect the station examined in this lawsuit from tsunamis of the same scale as the tsunami calculations would be highly likely to serve mainly to prevent the entry of seawater from the southeast face of the station; even taking into account the possibility that seawalls would be designed to include a given degree of margin, it would not have served to prevent the ingress of a great amount of seawater into the station at the arrival of the tsunami.” The court also stated: “It is highly likely that such a large amount of seawater would have entered the main buildings, flooded and crippled emergency power supply, caused the nuclear reactor facilities to black out, and generated an accident of the same scale of the disaster experienced in this lawsuit.” In conclusion, the Supreme Court denied the causal link between the lack of exertion of regulatory authority and the occurrence of the disaster, stating. “Under the factual conditions presented in this case, a factual relation cannot be found to exist between the lack of exertion of the abovementioned regulatory authority by the Minister of Economy, Trade and Industry and the occurrence of the accident examined in this lawsuit or similar accident.” The court judged that the government is not liable to compensate for damages according to Paragraph 1, Article 1 of the Law Concerning State Liability for Compensation.


Dissenting opinion by Judge Miura acutely reveals the truth

The Supreme Court Petty Bench consists of five judges, but Otani Naoto, Chief Justice of the Supreme Court, does not participate in the examination of individual cases. The four judges who conducted this case were Kanno Hiroyuki (former judge), Miura Mamoru (former prosecutor), Kusano Koichi (former attorney), and Okamura Kazumi (former prosecutor, attorney, and government official).

Besides the fact-finding section, the majority opinion (by judges Kanno, Kusano and Okamura) consists of only six pages, denying the liability of the government. On the other hand, the dissenting opinion (by judge Miura) is 29 pages long, and clearly states that the government is liable: “The government and the utility company, TEPCO, are held liable for damages to the plaintiffs, and it is reasonable to understand that the two are under non-authentic joint obligations (meaning that both parties are liable, but that releasing one party from liability does not automatically release the other party from the same liability).” The dissenting opinion is summarized below:

  1. In the Technical Standards based on the Electricity Business Act, “the cases where nuclear reactor facilities and the like may be damaged by tsunamis,” are cases where, in consideration of the severest foreseeable tsunami conditions, the safety functions of nuclear reactor facilities and the like may be crippled by tsunamis, which should be assessed appropriately by means of numerical calculations and other relevant means, based on the latest scientific and expert knowledge, and in consideration of the uncertainty of various factors from a conservative (safer) point of view, to encompass tsunamis that may occur, however rarely, during the service period of the facilities.
  2. The Long-term Assessment was conducted to evaluate the occurrence of future earthquake activity in the area ranging from the offshore area of the Sanriku Coast (extending from Aomori to Miyagi Prefectures in northern Japan) to the offshore area of the Boso Peninsula (in Chiba Prefecture in the south), as part of a comprehensive evaluation of earthquakes, to promote the improvement of earthquake disaster prevention measures. The basic reliability of the Assessment can be secured in that the Assessment was conducted by appropriate methods using previously established scientific and expert knowledge. The Assessment is reasonable for use as the basis of the determination of technological standards.
  3. At that time, in Japan and in other countries, watertight defense measures were known to be implemented in nuclear reactor facilities. Technological knowledge for the prevention of flooding for doors, openings, penetrations and the like is available. It can be considered that, if watertight defense measures or other relevant measures were taken, it might have effectively protected the emergency power supply examined in this lawsuit against the tsunami.


Let’s overturn the Supreme Court majority opinion

The majority opinion of the Supreme Court bailed out the delinquent national government, ignoring the fact that regulatory administration can be effective only when the government exerts regulatory authority at the right time and in the right situations. We might say that the judicial system has managed to come down to a very low level here.

The majority opinion of the Supreme Court includes incorrect factual findings, judgment failures and contradictions. The second lawsuit of the Chiba plaintiff group is pending at the Tokyo Hight Court. We intend to make the best efforts possible to present further assertions and proofs needed to turn the dissenting opinion of the Supreme Court decision into a majority opinion. We thank you for your continued support.

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