For the explanation of hysteria: 1) Nuclear disasters are acute, traumatic events that can have drastic effects on health of people and ecosystems for generations 2) Nuclear power sounds like nuclear bombs and nuclear radiation, both of which are scary and resonate with long-held cultural fears of nuclear technology that have existed since the Cold War.

Basically, yes most fears of nuclear power are irrational. But that's part of the problem—even if nuclear power polluted in a manner similar to coal power and there wasn't the risk of acute disaster, I still think Americans would be quite wary of the technology purely due to cultural priors.