The crisis at the Fukushima nuclear plant was "a profoundly man-made disaster", a Japanese parliamentary panel has said in a report.
The disaster "could and should have been foreseen and prevented" and its effects "mitigated by a more effective human response", it said.
The report catalogued serious deficiencies in both the government and plant operator Tepco's response.
It also blamed cultural conventions and a reluctance to question authority.
The six-reactor Fukushima Daiichi nuclear plant was badly damaged after the 11 March 2011 earthquake and tsunami knocked out cooling systems to reactors, leading to meltdowns and the release of radioactivity.
Tens of thousands of residents were evacuated from an exclusion zone around the plant as workers battled to bring reactors under control.
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