Three Mile Island Accident
by Marci RanzerOn March 29, 1979 the worst nuclear disaster in U.S. history occurred at the Three Mile Island nuclear power plant in Dauphin County Pennsylvania. The Three Mile Island disaster demonstrated the American public’s most terrible fears of nuclear technology.
The core in the reactor 2 unit experienced a partial melt down. This was the result of a combination of a jammed valve and human error. Under normal conditions the fuel rods in the reactor are covered with water which circulates and keeps them cool. However, a valve was caught open, allowing water to escape from the vessel. The water which was contaminated with radioactivity was pumped to an adjoining building and it was during this process that some radioactivity was released into the atmosphere.
The reactor operators misinterpreted their instrument readings and thought that the reactor had too much water. Because of this, they shelled off the emergency cooling water. The heat from the core boiled off more of the water, and then the core began to melt. About one half to one third of it melted before the operators realized what had happened and resumed the flow of emergency water. The hot metal in the fuel rods reacted with the water producing hydrogen gas which prevented the water from being pushed back into the vessel. The danger was that the effervescing of radioactive hydrogen gas could explode causing a greater release of radiation. Officials made plans for a possible evacuation.
United States President Jimmy Carter spoke the following:
“To the people who live around the Three Mile Island plant, that if it does become necessary, your Governor, Governor Thornburgh will ask you and others is it necessary to take appropriate action to ensure your safety. If he does, I want to urge that these instructions be carried out calmly and exactly as they have been in the past few days.”
Three Mile Island health issues were a major concern after the accident. About 25,000 people lived within five miles of the accident. Pennsylvania Governor Richard Thornburgh advised the evacuation of pregnant women and young children living within five miles and Three Miles Island accident. Schools were closed and young children without relatives were taken to a nearby sports stadium. President Carter who holds a Post Graduate degree in nuclear physics toured the accident site. His goal was to get first hand detailed information and the 3 Mile Island disaster, as well as show his support for the local residents.
However, an evacuation was never needed, eventually the hydrogen gas bubble was dissipated and the rods were covered with water again. The 3 Mile Island disaster was no longer a threat to the nearby Pennsylvania citizens. The gases that ended up leaking into the atmosphere were almost entirely chemically emerged. Being that the gasses were not retained within the human body, the risk of Three Mile Island health issues was no longer something to worry about.
Even though the released radiation was minor, the Three Mile Island accident was considered major because a total core melt down became a real possibility. A melt down could occur if the steam explosion shattered the four-foot thick walls of the containment building or if the molten core burnt through the concrete base and deep into the earth. If this containment failure occurred, then the radiation could contaminate a 30-mile radius area.
Due to the Three Mile Island disaster, the public realized that a serious nuclear plant accident was in a realm of possibility. Therefore, the debate over nuclear energy was made stronger and after the accident the amount of American citizens who supported nuclear power plants decreased in number.
