its delayed disclosure of the meltdowns at three reactorswas tantamount to a cover-up
NYT:
Culture of Complicity Tied to Stricken Nuclear Plant
Mainichi:
then TEPCO president Masataka Shimizu had ordered the company not to use the term “meltdown” to describe what had occurred
None of these support anything close to the kind of cover up needed to result in a “nobody can know how many people died” level of lack of information. They’re mostly about failing to report the disaster fast enough and downplaying it by using certain wording and having a lax security culture. Not about the government preventing investigations or giving gag orders or something like that.