The nation’s worst commercial nuclear accident, the core meltdown at Three Mile Island led first to a complete halt in the construction of nuclear power plants, then to serious economic and public-relations consequences for the United States’ nuclear power industry.
Radiation alarms, activated by contaminated water, sounded, but they were initially ignored. Not realizing the plant was experiencing a loss of coolant, operators initiated a series of actions that made conditions worse by further reducing the coolant through the core. Consequently, the nuclear fuel overheated to a point at which the zirconium cladding (tubes holding the nuclear fuel pellets) ruptured and began to melt. It was later determined that about one-half the core melted during the early stages of the accident. Radiation levels were around three hundred times expected levels, and the plant was seriously contaminated. Although the plant suffered a severe core meltdown, the building’s containment wall was not breached. Such a breach could have caused a massive release of radiation into the environment.
The Three Mile Island nuclear plant in 1999, with the damaged unit at left.
The incident at Three Mile Island caught federal and state authorities unprepared for such an emergency. Plant personnel initially had difficulty establishing communication with the Nuclear Regulatory Commission’s regional office, and there was no planned evacuation route. Governor of Pennsylvania Richard Thornburg advised that pregnant women and young children within a five-mile radius of the plant be evacuated, but no general evacuation was ordered. The crisis continued through April 1. Although the damage to the reactor was serious, the radiation was contained, and the amount released had a negligible effect on the physical health of people in the area or on the environment. The reactor was permanently shut down, and the damage caused by the meltdown was estimated at $500 million. Cleanup of the site continued through 1993.
Despite the relatively benign outcome of the accident, the fear it generated continued to haunt the nuclear power industry. Immediately after March, 1979, public approval of nuclear power fell, as did construction orders for nuclear reactors. Three Mile Island became an iconic symbol of the dangers of nuclear power, later joined by Chernobyl. The disasters in these two locations are often invoked by opponents of nuclear power seeking to build public distrust and defeat proposals for new nuclear power facilities.
Stephens, Mark. Three Mile Island. New York: Random House, 1980. Walker, Samuel. Three Mile Island: A Nuclear Crisis in Historical Perspective. Berkeley: University of California Press, 2004. Whitford, David. “Going Nuclear.” Fortune 6 (August, 2007): 42-54.
U.S. Department of Energy
Energy crisis of 1979
Nuclear power industry
Occupational Safety and Health Act
Tennessee Valley Authority