Respectfully, they overreacted. Fukushima killed effectively no-one from radiation, though fear of radiation did definitely kill people (as they evacuated). Meanwhile air pollution from fossil fuel is killing hundreds of thousands per year from air pollution. Now factor in potential impacts from climate change... fear of nuclear for safety purposes is real but doesn't stand up to the actuary test. And the fact is that this fear translates into extra regulations and safety systems that cost a lot so it's not just "but nuclear is expensive". A better solution is like TerraPower is taking, just design inherently safer reactors that don't need the safety systems.