Three Mile Island accident

From the Simple English Wikipedia, the free encyclopedia that anyone can change

The English used in this article may not be easy for everybody to understand.
An editor's reason for this is: Still uses some complex words and sentence structures

You can help Wikipedia by making this page or section simpler.

The 1979 Three Mile Island accident at the Three Mile Island Nuclear Power Plant in Pennsylvania was "the single most important event in the fifty-year history of nuclear power regulation in the United States". Many commentators have seen the event as a turning point for the nuclear power industry in the United States.^[1]

The Three Mile Island power station is near Harrisburg, Pennsylvania in the United States. The accident began on Wednesday, March 28, 1979, and ultimately resulted in a partial core meltdown in Unit 2 of the nuclear power plant. Unit 2's pressurized water reactor was of 900 MWe capacity.^[2] The scope and complexity of this reactor accident became clear over the course of five days, as a number of agencies at the local, state and federal levels tried to solve the problem and decide whether the ongoing accident required an emergency evacuation, and to what extent.

The chain of events that led to the crisis at the TMI plant included several minor equipment failures, but operator errors (to which design flaws contributed) converted those malfunctions into a major accident.^[1] The Three Mile Island accident is largely seen as a failure of crisis management:^[3]

Reactor operators were not trained to deal with accident conditions, and the Nuclear Regulatory Commission (NRC) had not established effective communication with utilities. Moreover, once the accident occurred, the lines of authority proved to be ill defined. The public received conflicting reports that caused needless panic and evacuations. It was these systemic weaknesses in the regulatory system that allowed gifted people to make the mistakes they did.^[3]

About half of the TMI-2 reactor core melted, releasing large amounts of hydrogen gas into the reactor coolant system and into the containment building. Fortunately, the serious damage to the reactor did not result in any deaths, in large part because of the robust design of the plant's systems. The TMI-2 cleanup took 11 years and cost about US$1 billion.^[1]

The TMI accident led to widespread criticism of nuclear power technology, the nuclear industry, and the NRC. Critics faulted the industry and the NRC for their poor performance both before and after the accident. The international attention garnered by the crisis redoubled the determination of, and enhanced the credibility of, the anti-nuclear movement. Arguably, the United States nuclear industry has never recovered.^[4]