So says the Mainichi Shinbun reporters who must be reading the report submitted by TEPCO on May 23 and released on May 24 according to this story.
Category: Fukushima
This article on NHK confirms Tokyo Electric Power’s assessment that all three reactors melted to various degrees fairly soon after the earthquake. Other reports from reputable sources say the cooling systems were damaged by the earthquake and that the tsunami only added to the problems that contributed to deterioration of the systems.
Tepco released this footage of work progress inside the plant following earthquake, tsunami, meltdown of reactors.