In 1976 , four nuclear engineers — three from GE and one from the Nuclear Regulatory Commission — resigned , stating that nuclear power was not as safe as their superiors were claiming . They testified to the Joint Committee on Atomic Energy that : " the cumulative effect of all design defects and deficiencies in the design , construction and operations of nuclear power plants makes a nuclear power plant accident , in our opinion , a certain event . The only question is when , and where . On March 28 , 1979 , equipment failures and operator error contributed to loss of coolant and a partial core meltdown of Unit 2 's pressurized water reactor at the Three Mile Island Nuclear Power Plant in Pennsylvania . 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
Three Mile Island Nuclear Power Plant
Three Mile Island accident
Nuclear reactor accidents in the United States