I don’t recall much radioactivity being released. In fact, a dosimeter located in downtown York, PA, about 15 miles away, registered no change in radioactivity during the whole “crisis”.
This issue requires more technical knowledge to evaluate than I possess. The NRC fact sheet on the Three-Mile Accident says the following:
There was “A significant release of radiation from the plant’s auxiliary building”
...
And “Very low levels of radionuclides could be attributed to releases from the accident. However, comprehensive investigations and assessments by several well-respected organizations have concluded that in spite of serious damage to the reactor, most of the radiation was contained and that the actual release had negligible effects on the physical health of individuals or the environment.”
http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/3mile-isle.html
More directly to the issue I raised is that what I was wondering about was the connection between the left-wing movie, The China Syndrome, and the incident at Three-Mile Island.