The China Syndrome (1979)

While doing a series of reports on alternative energy sources, an opportunistic reporter (Jane Fonda) witnesses an accident at a nuclear power plant. She's determined to publicize the incident but soon finds herself entangled in a sinister conspiracy to keep the full impact of the incident a secret. With Jack Lemmon, Michael Douglas, and Wilford Brimley. A pretty good thriller, which was released a few days before the Three Mile Island nuclear accident in Pennsylvania.