The president of Tokyo Electric Power Co. (TEPCO) at the time of the 2011 nuclear accident instructed TEPCO officials not to use the term “core meltdown” in describing the status of its Fukushima Daiichi plant crippled by a devastating earthquake and ensuing tsunami, according to a report by a third-party exploratory committee commissioned by the utility.
The panel submitted the report to TEPCO on June 16 acknowledging that the instruction was issued by then President Masataka Shimizu. At that time, TEPCO officials would only say core nuclear reactor parts had been damaged when, in reality, nuclear fuel was melting and falling to the bottom of the reactors. The report said it can be presumed that TEPCO continued such explanations in the early days of the accident due to pressure from the Prime Minister’s Office.
The disclosure of top management involvement in playing down the nuclear crisis shows the lack of a sense of risk control and a cover-up mindset, raising questions about corporate governance.
According to the report, Shimizu had a public relations official hand a memo to Sakae Muto, then vice president, who was present at a press conference on the night of March 14, 2011, three days after the accident. The memo had words such as “core meltdown’ written down and a TEPCO staffer hissed into Muto’s ear an instruction not to use the term saying this was at the direction of the Prime Minister’s Office.
At the time of the accident, the proportion of damaged core parts of the Nos. 1-3 reactors at the nuclear complex exceeded 5% of the total from March 14 to 15, a level equivalent to a meltdown under the company’s manual. A TEPCO emergency response team reported the damage ratio to the head office and others concerned, but did not describe it as a core meltdown.
Regarding this response, the committee termed the reference to the damage ratio alone insufficient in terms of communication to relevant municipal authorities and residents, and concluded that “labeling the accident as being tantamount to a core meltdown would have been more reasonable.”