Not only did they not flee, they still buy as much of their fruits and vegetables as possible from Fukushima Prefecture.
He knew what most people in science knew. Hundreds of thousands of people fleeing over radiation levels that were less than background radiation makes sense in a 'better safe than sorry' way, but the anti-science public relations campaign against nuclear power is more myth than data. Guarapari Beach in Brazil has background radiation way above permitted levels in terms of what the public can be exposed to but it’s coming out of the soil. It's all natural. People cover themselves in that sand because they claim it cures pain.
Wasn't he worried about another Chernobyl? Most of the problems related to Chernobyl have been mental - people were so worried about living in Hiroshima due to media and activist campaigns telling them they were going to die that they became ill in ways that had nothing to do with radiation. It was wise for them not to trust the leaders in the Soviet Union, for sure. 6,000-odd cases of thyroid cancer happened because the elites did not mention that contaminated grass eaten by cows that then gave milk could cause problems.
Everything you thought you knew about the risks of nuclear energy is wrong by Paul Blustein, Quartz