Former Japanese official denies pressuring power company not to use the word ‘meltdown’ during Fukushima disaster

A Japanese opposition leader who was a senior official during the 2011 Fukushima nuclear plant crisis denied on Friday that he or the prime minister at the time pressured the president of Tokyo Electric Power Company not to use the term “meltdown”.

Democratic Party Secretary-General Yukio Edano called a special news conference to refute a finding in a new report that TEPCO president at the time Masataka Shimizu apparently came under political pressure not to use the word. The report did not find direct evidence of that.

“The fact that I or then-Prime Minister [Naoto] Kan ordered or requested then-President Shimizu to avoid using the term ‘meltdown’ under any circumstance does not exist,” Edano said. He said the timing of the report was suspicious ahead of an Upper House election next month.

The report released on Thursday by a team of three lawyers appointed by TEPCO found that an instruction from Shimizu to avoid using the term “meltdown” delayed full public disclosure of the status of the nuclear plant, which suffered three reactor meltdowns after a major earthquake and tsunami hit the northeastern Japanese coast on March 11, 2011.

The utility used the less serious phrase “core damage” for two months after the disaster.

TEPCO reported to authorities three days after the tsunami that the damage, based on a computer simulation, involved 25 to 55 per cent of the fuel but did not say it constituted a “meltdown”, the report said. Yet the company’s internal manual defined a meltdown as damage to more than 5 per cent of the fuel.

In May 2011, TEPCO finally used “meltdown” after another computer simulation showed fuel in one reactor had almost entirely melted and fallen to the bottom of the primary containment chamber, and that the two other reactor cores had melted significantly.

TEPCO has been accused of softening its language to cover up the seriousness of the disaster, though the investigation found TEPCO’s delayed acknowledgement did not break any law.

In the 70-page report, the lawyers said Shimizu instructed his deputy not to use the word “meltdown” during news conferences immediately after the crisis. TEPCO’s vice president at the time, Sakae Muto, used the phrase “possibility of meltdown” until March 14, 2011.

Video of a news conference that day shows a company official rushing over to Muto when he was about to respond to a question, showing him a memo and hissing into his ear, “The prime minister’s office says never to use this word.”

Yasuhisa Tanaka, the lawyer who headed the investigation, said interviews of 70 former and current TEPCO officials, including Muto and Shimizu, showed that Muto had planned to use the word “meltdown” until he saw the memo, which has not been found.

“Mr Shimizu’s understanding was the term ‘meltdown’ could not be used without permission from the prime minister’s office,” Tanaka said at a news conference at TEPCO headquarters. “The notion that the word should be avoided was shared company-wide. But we don’t believe it was a cover-up.”

Edano criticised the report as “inadequate and unilateral”, and said the team did not talk to him or Kan.

Tanaka said his investigation, which did not interview any government officials, could not track down what exactly happened between Shimizu and the prime minister’s office.

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The Nuclear and Industrial Safety Agency, Japan’s nuclear regulatory unit at the time, was also reluctant to use the word. Two spokesmen were replaced between March 12 and 13, 2011, after suggesting meltdowns had occurred.

TEPCO has said the delay in confirming the meltdowns did not affect the company’s response to the emergency.

The issue surfaced earlier this year in a separate investigation in which TEPCO acknowledged that a company manual had been overlooked, reversing its earlier position that it had no internal criteria for a meltdown. TEPCO has eliminated the definition of a meltdown from the manual in revisions after the Fukushima disaster.