April 5, 2004 Harrisburg, Pennsylvania and Washington, D. C.
- The worst American nuclear power plant accident began at 4:00 a.m. on March 28, 1979. The Unit 2 reactor at the Three Mile Island nuclear power facility near Harrisburg, Pennsylvania, overheated. Due to the loss of reactor coolant, fuel rods began to melt. Because the fuel rods were sticking up out of the lowered water level, the nuclear chain reaction could not be controlled. The rods actually melted into the remaining water, dropped to the bottom of the reactor where enough collected to start another uncontrolled nuclear chain reaction.
For five days, scientists and engineers struggled to prevent the unimaginable nightmare of a core melt down that would have poisoned all the Harrisburg population with radiation. Fortunately, the nuclear chain reaction was finally stopped, but a lot of radiation was released into the atmosphere. On March 29, 1979 - the second day of the ongoing crisis - the Nuclear Regulatory Commission (NRC) reported a reading of 3,000 millirads per hour taken above Three Mile Island. The 1979 President's Commission on Three Mile Island finally estimated that the radioactive release over thirty-one days to the environment ranged from 2.4 million to 13 million curies - or 13 megacuries.
"The total release of radioactivity to the enviroment from March 28 through April 27 has been established as 13 to 17 curies of iodine and 2.4 million to 13 million curies of noble gases." (Page 31, Section 13, 1979 Report of the President's Commission on the Accident at Three Mile Island.) For comparison, all combined radioactive isotope contamination at the Chernobyl melt down is estimated ato have been 100 to 130 million curies, or 100 to 130 megacuries.
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