1979年3月28日，Three Mile Island accident 發生於美國 Pennsylvania Harrisburg 附近的三哩島核電站。
事故源於2號反應爐冷卻系統故障，隨後因機械問題與操作失誤相互影響，導致反應爐核心出現部分熔毀。
雖然事故只釋放少量放射性氣體，並未造成即時死亡，但事件引起美國社會對核能安全的廣泛關注。
三哩島事故被視為 United States 歷史上最嚴重的核電事故之一。
事故之後，美國政府加強了核電站安全監管、操作員培訓以及應急處理制度，對全球核能安全政策亦產生重要影響。
English Article Version
On March 28, 1979, the Three Mile Island accident occurred at a nuclear power plant near Harrisburg, in the U.S. state of Pennsylvania.
The incident began with a malfunction in the cooling system of Reactor Unit 2. A series of mechanical failures and operator errors led to a partial meltdown of the reactor core.
Although only a small amount of radioactive gas was released into the environment and no immediate deaths were reported, the accident caused widespread public concern about nuclear safety.
The Three Mile Island incident became the most serious nuclear accident in the history of the United States.
Following the event, the U.S. government introduced stricter nuclear safety regulations, improved operator training, and enhanced emergency response procedures.
