Three Mile Island

THE WORST NUCLEAR accident in the history of the United States occurred at Pennsylvania's Three Mile Island (TMI) nuclear power plant in the predawn hours of March 28, 1979. The plant located approximately 10 miles south of Harrisburg, Pennsylvania, on the Susquehanna River, came dangerously close to a nuclear meltdown that could have had devastating results.

For nearly a year, the TMI plant had been successfully producing electricity. Problems began, however, when TMI's Unit 2 Reactor was hastily opened for operation at the end of December 1987. By January 1979, Unit 2 Reactor had to be shut down for two weeks while operators identified leaks in the piping and pump system. Problems began in the pump system of the Unit 2 Reactor, specifically in the secondary ...