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Honest confession of error at Fukushima nuclear accident

Honest confession of error at Fukushima nuclear accident

Posted May. 24, 2014 05:41,   


Frank confession by Masao Yoshida, director of the Fukushima nuclear power plant, known as "the man who saved Japan" by commanding the scene after the nuclear accident at the time of the earthquake in east Japan on March 11, 2011, has left strong resonance to people across Japan. After suffering from throat cancer, Yoshida died in July last year at the age of 58.

According to the Asahi Shimbun on Friday, Yoshida confessed at the state investigation and verification committee that because he lacked proper knowledge on how to control the isolation condenser (IC) that cools off the nuclear reactor on the day of the accident, he took a misguided response. An investigative hearing on him was conducted on 13 occasions for a combined total of 29 hours and 16 minutes from July 22 to November 6 in 2011. The Japanese government compiled the hearing into a report of questions and answers (dubbed “Yoshida investigation report”), and is keeping the report at the chief cabinet minister’s office (equivalent to the prime minister’s office in Korea).

At the hearing, Yoshida confessed that after learning the IC was not working properly on the day of accident, an operator at the control center asked him to refill cooling liquid, but he only continued instructing the operator to be ready to send water from the IC into the reactor. Only after he learned that the radiation level at reactor building No. 1 rose around 10 p.m. on the day, then he came to suspect occurrence of abnormality in the IC. The Japanese government judges that the reactor core already started to melt at 6 p.m. on the day and completely melted some two hours later.

Yoshida said he came to actually operate the IC for the first time in 20 years, admitting that “I was not well aware. Communications with the control center was not done properly.” He added, “I am deeply reflecting upon the error right now.”

On explosion of hydrogen that was leaked from reactor No. 1 on March 12, 2011, Yoshida said, “I had never imagined that hydrogen would have accumulated.” Regarding ways to recover from the massive accident, there was no advice from Tokyo Electric Power’s headquarters, and when crisis situation occurred at reactor No. 1 four days after the initial accident, 90 percent of staff on duty at the site ran away despite his order to stay put.

At many parts of his testimonies, Yoshida made remarks of reflection and atonement, saying “I was only thinking self-righteously,” and “Maydays from the accident site were not communicated.” The newspaper said, “Even for a professional at a nuclear power plant, it was difficult to overcome confusion and thought of self-righteousness,” adding, “This is an important lesson from the Yoshida investigation report.”

The nuclear regulation project team at the ruling Liberal Democratic Party of Japan asked the government to grant access to the Yoshida report to examine countermeasures for a future accident, saying, “Such an accident should never happen again, but an accident inevitably occurs.” The Japanese government plans to disclose the report if Yoshida’s bereaved family agrees to publicize it despite his request not to disclose.

Experts have said that Yoshida prevented the accident from spreading further by continuously pumping seawater into the reactors in the afternoon of the day following the accident, despite instructions otherwise by then Prime Minister Naoto Kan and Tokyo Electric Power Co. For eight months from the time of the accident to November that year when he left the site due to throat cancer, the level of his radiation exposure amounted to 70mSv, which was as many as 70 times the level of ordinary people’s annual radiation exposure (1mSv).