Dale’s Daily Data: Three Mile Island

Today is the 32nd anniversary of this country’s worst accident in the nuclear power industry – a pressure valve failed to close in one of the reactors at the Three Mile Island power plant – 10 miles from Harrisburg, Pennsylvania.  Water contaminated with radiation began to flood the building and the core began to overheat.  Automatic safety features detected the rising temperatures and emergency cooling pumps poured thousands of gallons of water onto the core.  But workers in the control room were confused by some of the information they were getting and when they shut down the reactor, at the same time they were also shutting down the emergency cooling system.

 By the time workers figured out what happened, the core had come within a half hour of a complete meltdown.  More than half the core had been destroyed but no radiation escaped.  Two days later, they found the accident had created hydrogen gas inside the reactor and some of it had been released into the air, so as a precaution, pregnant women and young children within a five mile radius were advised to evacuate.  But, that advisory led to a panic evacuation of 100-thousand people from surrounding towns.  It wasn’t until President Carter personally visited the plant that people began to return.

It happened, March 28, 1979.