I have a much simpler theory. Everytime an "event" occurs, nuclear scientists tell us, everything is ok, it is all handled, and then shortly thereafter, leaks are discovered to be worse than reported, handling of waste is done very poorly, or things just implode, as they did in Fukishama.
But the thing is, this is no worse than how "events" in other areas are handled. I don't trust reports of nuclear accidents any less than I trust reports of refinery or offshore oil-well or chemical plant or ... accidents.
http://www.king5.com/news/investigators/Hanford-no-ENRAF-nuc...
http://www.nytimes.com/2013/06/06/world/asia/tepco-says-wate...
Stop looking for elaborate answers. As a "lay" person, my impression is that their credibility is completely shot.