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> 1999
> March
> March 26, 1999:
Hour One: Three Mile Island Anniversary
| Twenty years ago, on March 28, 1979, thousands of Pennsylvania residents were very, very worried. They were faced with the worst nuclear power accident in the nation's history - the accident on Three Mile Island.
Early that morning, about 4 am, some of the main feedwater pumps stopped running in Three Mile Island's Unit Two. Those pumps were supposed to remove heat from the reactor, which had been on line for only three months. The temperature inside the reactor began to rise, and pressure began to build. A relief valve opened to let off the excess pressure - and then stuck open. The pressure fell below normal levels. | 
Image courtesy PA State Archives | Another emergency cooling water system was supposed to come into play, and in fact had been tested only two days before the accident - but because someone forgot to reopen a valve in this backup cooling system after the test, it did not work properly. Eight minutes later, the valve was opened, and water began to flow through the backup system. But because a gauge incorrectly said the main system was full of water, the plant operator shut down some pumps and stopped adding water, and the temperature began to rise again.
(image courtesy Nuclear Regulatory Commission)
Before the accident was through, between a third and a half of the reactor fuel had melted. Some radioactive gas was released to the outside. The reactor building's basement was filled with radioactively contaminated water.
Plant officials insisted that the accident wasn't nearly as bad as some were making it out to be - and was nowhere near the magnitude of the accident portrayed in the movie "The China Syndrome," which had been released just days before. The radiation release was minor, they claimed, the exposure for most people being the same as from a chest x-ray. But for five days, people near the plant worried, and wondered what to do. The governor considered ordering an evacuation of the area - and thousands of people fled anyway. And since the accident, no new nuclear power plants have been built in the United States.
What went wrong that morning, and in the days that followed? Was the accident as bad as some say - or as minor as others claim? And could it happen again today? Join Ira Flatow on this hour of Science Friday for a look at these - and other questions.
Listeners respond
Guests:
Anthony Baratta
Professor and Chair, Nuclear Engineering
Pennsylvania State University
University Park, Pennsylvania
Stephen Couch
Professor, Sociology
Pennsylvania State University Capital College
Schuylkill Haven, Pennsylvania
Susan Stranahan
Staff Writer
Philadelphia Inquirer
Conshohocken, Pennsylvania
Books/Articles Discussed:
Related Links:
Nuclear Regulatory Commission's summary of the accident
The American Experience:
Meltdown at Three Mile Island (PBS program)
TMI-2 Recovery and Decontamination Collection (at Penn State)
NRC : Three Mile Island Unit One (the OTHER reactor)
This segment produced by:
Karin Vergoth
Web producer:
Charles Bergquist
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