> Not because of fear but because the plants that are/were in operation are in terrible shape and predate back to the 60s and 70s mostly, with some exceptions.
Some sources on that:
For example, the Biblis NPP does not have any spatial separation of the power supply and control cables. A scenario like the one that actually occurred at the U.S. nuclear power plant at Browns Ferry on March 22, 1975, would therefore also be possible at Biblis: When searching for an air leak, the controller used a burning candle. The cables were surrounded by foam, which ignited on the candle flame. This was not detected until the foam was already burning and significant damage had already occurred to the power supply and control cables. As a result, the power failed and almost all of the plant's emergency cooling systems of the reactor were no longer functional. Only one emergency cooling system was still available in Unit 2. Without adequate cooling, a meltdown can occur because radioactive decays in the reactors continue to generate such high heat after shutdown that reactor vessels could not withstand it. In the case of Browns Ferry, a meltdown was prevented because two condensate pumps that were present but actually intended for normal operating for the normal operating system were switched on.
It's translated from a study on nuclear power plant insurances [0]. The section section about the security dangers of nuclear power plants was really interesting to read. The study also talks about things like rocket launchers aimed at nuclear power plants, the damage airplanes can inflict on them, risks of insider attacks, as well as the costs of a nuclear catastrophy. It's a good read if you know German.
[0]: https://www.bee-ev.de/fileadmin/Publikationen/Studien/110511...