Chernobyl and Fukushima. These two events, which between them account for a few thousand deaths at most (compared with the tens of thousands of deaths caused by coal in Europe alone, for example), triggered a panic fear of nuclear power.
For decades, the nuclear industry has been abandoned and sabotaged, with projects such as Phénix, Superphénix and Astrid in France, and virtually all new reactor projects, cancelled due to anti-nuclear opposition.
Competent nuclear engineers and technicians have retired without being able to pass on their know-how, and cutting-edge nuclear-related industries have disappeared or been converted.
We can also thank the Germans for sabotaging the EPR. We started the project together, they forced us to add a lot of totally unjustified redundancies and safety features that made the prototype very complex and therefore costly to build, and then they slammed the door on us.