Three Mile Island accident facts for kids
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The Three Mile Island accident happened on March 28, 1979. It took place at the Three Mile Island Nuclear Power Plant in Pennsylvania. This event was very important for how nuclear power is managed in the United States. Many people see it as a major turning point for the nuclear power industry.
The power plant is located near Harrisburg, Pennsylvania. The accident caused a partial meltdown of the reactor core in Unit 2. This reactor was a pressurized water reactor and could produce 900 megawatts of electricity.
Contents
What Caused the Accident?
The accident started with a few small equipment problems. However, mistakes made by the plant operators made these problems much worse. This led to a serious accident. Many experts believe the Three Mile Island accident was mainly a failure of how the crisis was managed.
Operator Mistakes and Communication Problems
The people running the reactor were not trained for accident conditions. Also, the Nuclear Regulatory Commission (NRC) did not have good ways to talk with the power companies. When the accident happened, it was unclear who was in charge. The public received confusing information. This caused a lot of panic and led to people leaving their homes. These problems in the system allowed smart people to make serious mistakes.
The Core Meltdown and Hydrogen Bubble
A large part of the TMI-2 reactor core melted. However, it wasn't clear that a partial meltdown had happened until 1985. During the crisis, the biggest worry was a hydrogen bubble. This bubble formed at the top of the large container holding the reactor core.
Fears About the Hydrogen Bubble
Some experts worried that the hydrogen bubble could catch fire or even explode. This could happen if it mixed with oxygen inside the container. If the bubble exploded, it might break the container. This would push the damaged reactor core into the building designed to contain it. Breaking the container would not definitely cause radiation to escape. But it would greatly increase the risk of a dangerous release of radiation.
Impact and Cleanup
In the end, the Three Mile Island accident was a serious crisis. But it did not cause a major public health disaster. Even though the core melted, the main container held strong. The plant's containment structure was not broken. Only very small amounts of the most dangerous radiation escaped into the air. The cleanup of TMI-2 took 11 years. It cost about US$1 billion.
Long-Term Effects and Public Opinion
The Three Mile Island accident led to a lot of criticism. People criticized nuclear power technology, the nuclear industry, and the NRC. Critics said the industry and the NRC did not perform well before or after the accident. The crisis got a lot of attention worldwide. This made the anti-nuclear movement stronger and more believable. Many people believe the nuclear industry in the United States has never fully recovered since then.
Studies have looked for long-term health effects from the radiation. These studies have found different results. However, it seems that any increase in cancer cases is very small. It might even be due to chance.
Images for kids
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A sign from 1999 near the plant, describing the accident and the evacuation.
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A global history of nuclear power. The Three Mile Island accident is one reason new reactor building slowed down.
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A crew working to remove radioactive contamination at Three Mile Island.
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An anti-nuclear protest in Harrisburg, 1979, after the accident.
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After the accident, Three Mile Island used only one power station, TMI-1 (on the right). TMI-2 (on the left) has not been used since the accident.
See also
In Spanish: Accidente de Three Mile Island para niños
