I think it's possible that the reason for the unsafe nuclear power plants is a self-fulfilling prophecy. For example, in the US, there have been no new plants built since the 70s. What this means is that any advancements in technology haven't been taken full advantage of. The Fukushima plant was designed and built in the 60s.
People's collective fear of nuclear power, combined with government fulfillment of the hysteria, drives this halt in technological progress. I'm still a fan of nuclear in spite of recent mishaps, I just think we've been dealing with it in a juvenile and closed minded way as a society, creating dangers that otherwise would not exist.
RE: Fukushima clean-up going no where six years after tsunami