The head of the utility that runs the crippled Fukushima Daiichi nuclear power plant in northern Japan is apologizing for his predecessor's decision to ban employees from using the term "meltdown" during the early days of the crisis.

"I would say it was a cover-up," Tokyo Electric Power Company (TEPCO) President Naomi Hirose told reporters at a news conference.  "It is extremely regrettable.  People are justified in thinking it as a coverup," he said.

Last week, a report alleged that then-President Masataka Shimizu instructed vice president not to say "core meltdown" to describe the states of the reactors.  Video of the March 2011 news conference shows then-vice president Sakae Muto using the phrase "possibility of meltdown"; but a company official rushes over to Muto, shows him a memo, and whispers: "The Prime Minister's Office says never to use this word."  That memo has not been found, and last week's report didn't find any evidence that then-prime minister Naoto Khan tried to forbid the use of the word "meltdown". 

Khan's former spokesman, Yukio Edano, says their political party is considering a lawsuit against the compilers of last week's report.  Mr. Edano also suggested the allegations are timed to embarrass his party just before elections to choose members of the upper house.

On 11 March 2011, a powerful earthquake and giant tsunami devastated much of northern Japan, including the Fukushima Daiichi reactors.  For two months afterward, TEPCO officials would use only less serious phrase "core damage".  Eventually, the company had to admit a that a triple melt through had taken place, and to this day scientists don't know where the three highly radioactive cores went once they went through the floor of the plant.