I think the 2 most important factors to nuclear power stalling were: 1) Cold War and the fear of nuclear, and 2) the Chernobyl accident and its supposed consequences (which time demonstrated were extremely magnified at the time, probably also due to geopolitical benefits). Then anti-nuclear activism took on -primarily Greenpeace and its impact strategy which made the news most of the time- and made it politically unfeasible to support nuclear anymore which also stalled public nuclear R&D investment.