But the green movement was ultimately correct. They didn't know why and had nonsense arguments, but the fact is that "old nuclear" was developed with insufficient long-term safety. Fukushima showed that.
What also seems true is that you can't trust a company to run them properly, no matter the regulations and audits. TEPCO showed that. From people I know who've dealt with the nuclear industry, there is a strong contempt of regulation in sentiment/culture, likely due to the annoyances and perceived costs.
This contempt however breeds a long term apathy towards safety and maintenance. It's human nature.
There are reactor designs that are inherently meltdown proof (LFTR) and use almost all their nuclear fuel (LFTR) and can, I believe, breed old nuclear waste into usable fuel (LFTR). They scale down to small closet sizes (LFTR) and so can be more economically flexible. I believe pebble bed and others can do similar things. LFTR allegedly can be designed to be proliferation resistant, although I've seen opposing views from much better educated people.
But the LFTR goals should be the standard of the nuclear industry for next-gen. Not these massive solid rod huge dome boondoggle-prone eyesores.