I may agree with your conclusion that old plants are safe enough (or at least take a deep dive study to see if their expected externality is worse than whatever would replace them). However:

> the worst disaster to ever happen without any external factors

The problem is external factors happen. You can’t just raise your hands up and say “wasn’t my fault,” when they do. A tsunami washing over a solar farm would be a lot safer than what happened at Fukushima.

The Fukushima quake was a truly extraordinary outlier though!

4th biggest quake ever recorded in history hit at the exact spot where the tsunami could overpower the protective wall at the reactor. Yet nobody died from the radiation.

Meanwhile the 20k people who died in the tsunami are forgotten. No one demands we stop building cities by the ocean.