Not parent commenter, but I'll repeat what I said above to someone else about what fail-safe means in terms of nuclear reactors:
Fail-safe just means that if equipment breaks or a human does something wrong, the plant goes to low power and passive natural-circulation systems kick-in that keep the low-power shutdown mode from going to temperatures high enough to break the radiation containment structures.
Recall that coal plants and oil emissions kill 4-6 million people per year from air pollution. Nuclear plants are crazy safe compared to that. And while natural gas is safe from an air pollution POV, the hazards of climate change from it are potentially large. Nuclear reactors are essentially carbon-free.
