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.
I do believe that many reactors running today have been on line beyond what was projected to be their life span. I am a die hard conservative freedom loving capitalist so don't misread my concerns. I just feel when the results of a mistake have such catastrophic consequences maybe we need to take another look at things before plowing ahead. The US has an enormous amount of coal left to burn if we can figure out the emission issues.