What happened at Three Mile Island, Chernobyl and Fukushima Daiichi? And where are we now?

Certain objectives, principles and approaches related to the safety and protection from radiation of the environment and people (the public and employees) are taken into account to design and run nuclear power stations. Safety is being continually improved by taking under consideration: changing perceptions of risks; the new knowledge acquired about the complex phenomena that might occur inside reactors; and the experience gained from operating nuclear power stations, in particular the lessons learned from the big accidents involving the fusion of a reactor's core at Three Mile Island (1979), Chernobyl (1986) and Fukushima (2011). From these three accidents, quite different lessons can be drawn about operating nuclear reactors to generate electricity. The ultimate purpose of all the concrete measures adopted following these experiences is to reinforce prevention and limit the effects of such accidents. Since the 1990s, an internationally adopted principle is, when designing a new generation of reactors, to garner feedback from accidents involving the fusion of a reactor's core. (author)