Overview
The earthquake struck at 14:46 on 11 March 2011 and the wave arrived about fifty minutes later. It overtopped the seawall at Fukushima Daiichi, flooded the basements where the backup generators sat, and removed the plant's ability to cool its reactors. Fuel in units 1, 2 and 3 began to melt within days.
What the operator said about that, and when, is the substance of this entry — because on this one the company has since agreed with its critics.
The Word
Tokyo Electric Power Company avoided the word meltdown for two months. Its public descriptions used core damage, a term that sounds serious and means something considerably less specific.
The distinction was not academic. People were being evacuated in expanding rings around the plant, and the difference between damaged fuel and fuel that has melted through its assemblies bears directly on how far and how urgently anyone should go.
In February 2016 the company acknowledged that its own criteria at the time would have supported declaring a meltdown within three days. In June an investigation by three company-appointed lawyers reported that the then-president, Masataka Shimizu, had instructed officials not to use the word, and that he had done so under pressure from the Prime Minister's Office. The company's president in 2016, Naomi Hirose, said publicly that the delay was tantamount to a cover-up and apologised. He took a pay cut for a month.
The report also found that the delayed disclosure had not been illegal, which is a narrower finding than the apology implies and is generally left out of the retellings.
The Diet Inquiry
The conclusion that carried further came earlier. The National Diet's independent investigation commission reported in July 2012 and did not confine itself to the wave.
It described the accident as profoundly man-made, and located the causes in the relationship between the operator, the regulator and the ministry — a regulatory culture in which the industry effectively supervised itself, in which known seismic and tsunami risks had been assessed and not acted on, and in which deference discouraged anyone from insisting. It was an unusually direct document for a Japanese official inquiry, and its chairman wrote in the English edition that the disaster was rooted in conventions of Japanese culture including reflexive obedience and reluctance to question authority.
Where the Claims Go Further
Beyond the documented delay sits a larger body of claims: that radiation releases were far greater than reported, that the Pacific has been contaminated at levels being concealed, that health effects across Japan and the American west coast have been suppressed, and that the treated water discharged from 2023 is materially more dangerous than stated.
The measured record does not support the strongest versions. The IAEA, independent monitoring and Japanese and international academic work have tracked releases and marine dispersal continuously. The evacuation itself caused documented deaths — more than a thousand, largely among elderly people moved from hospitals and care homes — while radiation-attributable deaths among the public have not been established at population scale, a finding that satisfies neither the industry's critics nor its defenders.
Why the Larger Claims Have Traction
The reason is straightforward and it is the operator's own doing. A company that spent two months avoiding an accurate word, under instruction from its president, at the direction of the Prime Minister's Office, has forfeited the presumption that its later numbers are complete.
That is the actual legacy of the episode. The specific cover-up is documented, admitted and bounded — it concerned terminology over a period of weeks. But an institution that concealed the severity of an accident while people were being evacuated cannot then ask to be believed about the parts nobody can independently measure. The suspicion attaching to every subsequent release figure is not evidence that those figures are wrong. It is the predictable cost of the two months.