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
Nuclear chain reaction another fission. The remaining neutrons either are absorbed in non-fission reactions or leave the system without being absorbed. The value of "k" determines how a nuclear chain reaction proceeds: When describing kinetics and dynamics of nuclear reactors, and also in the practice of reactor operation, the concept of reactivity is used, which characterizes the deflection of reactor from the critical state. ρ=(k-1)/k. InHour is a unit of reactivity of a nuclear reactor. In a nuclear reactor, "k" will actually oscillate from slightly less than 1 to slightly more than 1, due primarily to thermal effects (as more power is produced,