March 28, 1979. If you lived in Pennsylvania at the time, you undoubtedly know the significance of that date. If that’s before your time, you’ve likely learned of it in history class. As Pennsylvanians went to bed the night before, little did they know that one of the worst disasters in U.S. history was only hours away. Here’s a brief summary of what turned out to be a very complex accident.
Sat along the Susquehanna River, Three Mile Island Nuclear Generating Station still operates today in Londonderry Township, only three miles from Middletown and just a half an hour from Harrisburg.
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What would become one of the worst disasters in U.S. history began at 4 a.m. when the failure of a cooling system kicked off a chain reaction of events that would release radiation into the air and as far away as Harrisburg.
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The TM2 reactor, one of two at Three Mile Island, suffered either an electrical or a mechanical failure in the water pumps that ensure the reactor’s core stayed cool.
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Employees, unaware of the malfunction, followed protocol that would keep the necessary cooling water to flow into the reactor.
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Overheating in the nuclear fuel then occurred. That resulted in the melting of approximately 50 percent of the nuclear reactor’s core, which sent radioactive gas and water into the air.
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Some witnesses who lived near the nuclear power plant described hearing a loud noise and seeing steam jutting into the air. Initially, those in charge at Three Mile Island asserted that any radiation that may have been leaked would not affect the surrounding communities.
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However, more than a day later, the area went into a virtual shutdown. School was canceled. Pregnant women were advised to leave the area. And, the PA government advised all residents within a five-mile radius remain inside. Within two days, that radius increased to 20 miles. Most of those who evacuated returned to their homes within a month.
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No deaths occurred in the immediate aftermath of the worst nuclear accident in U.S. history. However, debate continues today whether instances of cancer, and in particular thyroid cancer, in residents near the power plant are linked to the radiation released in March 1979.
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The final chapter of Three Mile Island will end in September 2019. That’s when, due to profit losses, the nuclear power plant will permanently close.
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Do you have memories of the accident at Three Mile Island, one of the worst disasters in U.S. history, and its aftermath? Share below! Then, click here to read more about Donora, a small PA town with a deadly history.
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