Nuclear Safety: Probability Theory Is Unsafe

KENICHI OHMAE |  The Japan Times

A year has now passed since the complete core meltdowns of three boiling water reactors at Tokyo Electric Power Co.’s Fukushima No. 1 plant. Because of the limited and biased information issued by the Japanese government, the world does not know what really happened when the earthquake and the tsunami hit the six Fukushima nuclear reactors. There are many important lessons that must be learned to avoid a future disaster. These lessons can be applied to all the nuclear reactors globally. People around the world deserve the right to know what happened.

Nuclear nightmare: The destroyed No. 3 reactor building at Tokyo Electric Power Co.’s Fukushima No.1 nuclear power plant on Feb. 20. The earthquake and tsunami that struck March 11, 2011, crippled Nos. 1, 2 and 3 reactors at the plant, triggering the world’s worst nuclear crisis since the 1986 Chernobyl incident. AP

As a nuclear core designer and someone who earned a Ph.D. from the Massachusetts Institute of Technology in nuclear engineering, I volunteered to look into the situation at Fukushima No. 1 in June of 2011. Mr. Goushi Hosono, minister of nuclear power and environment, personally gave me access to the information and personnel who were directly involved in the containment operations of the postdisaster nuclear plants. After three months of investigation, I analyzed and wrote a long report detailing minute by minute how the nuclear reactors were actually disabled (pr.bbt757.com/eng/)

Here are the highlights of my findings:

1. Three of the six reactors of Fukushima No. 1 had a complete core meltdown a few days after the tsunami hit. The molten fuel penetrated not only through the bottom of the thick pressure vessel, but also poked holes at the bottom of the containment vessel, thus releasing fission materials into the environment. The meltdown itself started at 11p.m. on the day of the tsunami, March 11, 2011.