July 12, 2022
<The “warning” that was not utilized

 On July 13, the Tokyo District Court will issue a ruling on a shareholder lawsuit seeking to hold five former TEPCO executives responsible for the accident at the Fukushima Daiichi Nuclear Power Plant. The possibility of a giant tsunami off the coast of Fukushima Prefecture surfaced nearly 10 years before the accident occurred. Why were tsunami countermeasures continually postponed? Ahead of the verdict, we take a look back at the evidence presented in court. (Keiichi Ozawa)

 TEPCO Shareholders’ Suit 48 shareholders are demanding that former TEPCO chairman Tsunehisa Katsumata and five others pay approximately 22 trillion yen in compensation to TEPCO for damages, decommissioning costs, and other losses caused by the former management’s failure to take tsunami countermeasures following the Fukushima Daiichi Nuclear Power Plant accident. The other defendants are former president Masataka Shimizu, former vice president Ichiro Takekuro, former vice president Sakae Muto, and former managing director Akio Komori. Katsumata, Takekuro, and Muto were indicted on charges of manslaughter in connection with the nuclear accident, but the Tokyo District Court ruled in 2007 that they were not guilty. In June, the Supreme Court ruled against the government’s responsibility in a lawsuit against nuclear power plant evacuees and confirmed that TEPCO must pay a total of approximately 1.4 billion yen in compensation to plaintiffs in four lawsuits in Fukushima, Gunma, Chiba, and Ehime.
 In July 2002, the government’s Headquarters for Earthquake Research Promotion released a “long-term assessment” of earthquake forecasts, including those for the area off Fukushima Prefecture. The reliability of this long-term assessment is one of the points of contention in the lawsuit.
 The long-term assessment is not a finding, but an opinion.
 At the oral argument last July, Sakae Mutoh, former vice president of the defendant, stood in front of the witness stand and emphasized that the long-term evaluation is not a finding but an opinion. The former management team claims that the long-term assessment was not reliable enough to determine the tsunami countermeasures, as some experts disagreed with the assessment.
 In August 2002, the Nuclear and Industrial Safety Agency of the Ministry of Economy, Trade and Industry (METI) requested TEPCO to estimate the tsunami based on the long-term assessment. However, an e-mail sent by a TEPCO official to the relevant parties states that the company “resisted the request for about 40 minutes.

Regarding a request from the then Nuclear and Industrial Safety Agency (NISA) for an estimate based on a long-term evaluation, a TEPCO representative reported in an e-mail to the relevant parties that he “resisted for about 40 minutes” (the e-mail material was provided by freelance journalist Takashi Soeda).

NISA further instructed TEPCO to investigate how the long-term assessment was prepared, but the person in charge merely sent an e-mail inquiry to Kenji Satake, a member of the promotion headquarters (now director of the Earthquake Research Institute of the University of Tokyo), who was skeptical about the occurrence of a tsunami off Fukushima Prefecture. The NISA did not pursue TEPCO any further.

 Later, in December 2004, a tsunami caused by an earthquake off the coast of Sumatra, Indonesia, submerged a nuclear power plant in India. The plaintiffs claimed that they could have learned from this accident, but TEPCO did not take any action.

 In September 2006, the “Guidelines for the Examination of Seismic Design” for nuclear power plants were revised to include tsunami countermeasures, and the NISA was assigned to conduct “seismic backchecks. In October of the same year, the NISA gathered together the personnel in charge of the power companies and instructed them to “promptly study tsunami countermeasures and take action.

 At the time, the tsunami height expected at the Fukushima Daiichi Nuclear Power Plant was 5.7 meters. The height of the tsunami that the facility could withstand was the same 5.7 meters, making it the plant with the least margin of safety in the nation. Even so, TEPCO did not initiate countermeasures. The Tokyo District Public Prosecutors Office’s report to the head of the NISA’s review team, submitted in the lawsuit, states, “(TEPCO) is really reluctant to incur costs. Frankly, I was angry at the slow response.

 In response to such backward-looking attitude on the part of the former management, the plaintiffs said, “If there is a warning with reasonable credibility, we should take measures for the time being. The attitude of wasting time while leaving it unattended is unacceptable.

 In 2008, TEPCO took a heavy stance. It sought advice from Fumihiko Imamura, a professor of tsunami engineering at Tohoku University and an expert in civil engineering, and began to study tsunami countermeasures. The issue was also discussed at the “Gozen Conference,” which was attended by the managing board and former TEPCO chairman Tsunehisa Katsumata, among others.

 In March of the same year, however, the situation changed when the height of the tsunami was estimated based on a long-term assessment. The tsunami was 15.7 meters high, nearly three times the previous height. The policy to proceed with countermeasures began to waver once again.