Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Three Mile Island refers to a nuclear power plant accident that occurred in 1979 near Harrisburg, Pennsylvania. It was caused by a partial meltdown of the reactor core.
Related terms
Nuclear Meltdown: A nuclear meltdown occurs when there is a severe failure in a nuclear reactor, leading to the overheating and melting of the reactor core.
Nuclear Power Plant: A facility that uses nuclear reactions to generate electricity.
Radiation: The emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization.