Nuclear reactor accidents in the United States 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
Timeline of the Fukushima Daiichi nuclear disaster spent nuclear fuel in the storage pool inside the reactor of unit 3. Water is sprayed into the reactor for a total of 7 hours during the day. TEPCO reports that the water was effective in lowering the temperature around the spent fuel rods to below 100 °C. External power is reconnected to unit 2, but work continues to make the equipment operational. Repaired diesel generators at unit 6 provide power to restart the cooling on units 5 and 6, both of which are returned to cold shutdown and their fuel cooling ponds returned to normal operating temperatures. TEPCO announces