Grisu was faster than me and pretty much said what I'd have said.
The safety regulations haven't been followed at all times as strictly as they should have been, and some of the technology and plants are outdated.
In addition to Grisu's links there are many more, e.g.
http://news.bbc.co.uk/1/hi/world/europe/934794.stm
http://www.greenworld.org.ru/eng/pro...aes/index.html
http://www.bellona.no/en/internation...ersk/8532.html