On this day 37 years ago the most serious accident in the history of American nuclear power happened. Three Mile Island, a power station situated in the Susquehanna River near Harrisburg, Pennsylvania, had partially been in operation since 1974. It actually comprised two stations, the second of which (TMI-2) had caused problems since the beginning and only began operating in 1978. At 4 a.m. an

automatically operating valve in this Unit falsely closed down, shutting off the water supply to the main system transferring heat from the water that actually circulated in the reactor core. A sequence of reactions followed: the reactor core shut down automatically, instruments began to malfunction providing confusing data, wrong decisions led to the closing of the emergency water supply, and the reactor core began to heat up dangerously. A melt-down, which would have released and spread deadly radiation, was just about prevented, and very little of the radioactive gases building and spreading inside the plant is said to have escaped into the open. Read further details here. Commemorating the event 25 years later, the Smithsonian National Museum of American History built a documentary site with a detailed outline of before-during-after the accident.

Initially, the authorities tried to play down the incident, but many residents in the area decided to leave. More here. As it later turned out, apart from psychological stress, those in the immediate vicinity did not suffer from health problems that could be directly linked to the accident.

Although the situation was soon under control, its effect was far-reaching:

  • security and safety became a greater priority for power plants, involving improvements in the quality of construction, maintenance and control;
  • posterior study of the accident led to a better understanding of the melt-down process (China Syndrome);
  • the public became much more sceptical and less trusty when it came to questions of nuclear power, which in turn led to a drastic decline of its public support. More here.

You can also watch a documentary about the incident:


Somewhat ironically, the accident occured twelve days after the release of the film China Syndrome (with Jane Fonda and Michael Douglas) which anticipated a similar crisis, though with a worse scenario. Combined, film and accident did much to intensify anti-nuclear campaigns.