自從人類發明核能之後，視其為乾淨及便宜之能源，許多國家便開始大量建造核能電廠，以享用此便宜之能源。但是由於核能電廠一直存在著輻射外洩之危險，因此其安全問題一直令人揮之不去，因為一旦發生重大核災，不但會造成嚴重輻射傷害，而且更可能貽害子孫。過去也曾經發生過幾次重大核安事故，例如美國三哩島、烏克蘭車諾比事故。而此次日本核災事故，造成嚴重之傷害，令國際震驚。由於我國也擁有核能電廠，因此有必要對這三大核災事故進行了解，從他們之錯誤中學習教訓，以確保我國核能電廠之安全無虞。

After the invention of nuclear energy by humankind, this kind of energy is considered as clean and cheap, and many countries began to build large nuclear power plants, in order to enjoy this cheap source of energy. However, due to the existence of nuclear energy that has been the danger of radiation leakage, the security issue has been lingering, since the event of a major nuclear accident happens, the radiation would not only cause serious injuries and are more likely harming future generations. Several major nuclear safety accidents have occurred in the past, such as - Three Mile Island in the U.S. and Ukraine Chernobyl nuclear power plant accidents. And the recent Japanese nuclear power plant accident, causing serious harm, shocked the international community. Since Taiwan also has nuclear power plants, it is necessary to study these three major nuclear disaster accident, learning from these lessons and to ensure that our nuclear power plants is safe.