Former Prime Minister Naoto Kan admitted Monday that the triple whammy that doomed the Fukushima No. 1 nuclear plant in March 2011 — the megaquake, tsunami and the meltdowns they unleashed — was beyond the scope of the national crisis-management system.

"The nuclear disaster special measures law does not assume a serious disaster" like Fukushima, Kan told a Diet panel probing the cause of the Fukushima crisis. Situations assumed under the law were "extremely insufficient."

This state of unpreparedness saw the prime minister's office fall into disarray, and saw communications with Tokyo Electric Power Co. — and even within the government itself — unravel, Kan said, adding he and his key ministers were not adequately briefed about the plant's situation in the first few days.