A system utilizing nuclear conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork is carried out in a controlled and self-sustaining manner. Neutrons are used to fission the conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork fuel, and the fission reaction produces not only energy and radiation but also additional neutrons. Thus a neutron chain reaction ensues. A nuclear reactor provides the assembly of materials to sustain and control the conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork chain reaction, to appropriately transport the heat produced from the fission reactions, and to provide the necessary safety features to cope with the radiation and radioactive conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork produced by its operation.
Nuclear reactors are used in a variety of ways as sources for energy, for nuclear irradiations, and to produce special materials by transmutation conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork. The generation of electrical energy by a nuclear power plant makes use of heat to produce steam or to heat conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork to drive turbogenerators. Direct conversion of the fission energy into useful conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork is possible, but an efficient process has not yet been realized to accomplish this. Thus, in its operation nuclear power plant is similar to the conventional coal-fired plant, except that the nuclear reactor is substituted for the conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork boiler as the source of heat.
The rating of a reactor is usually given in conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork (kW) or megawatts-thermal [MW(th)], representing the heat generation rate. The net output of electricity of a nuclear conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork is about one-third of the thermal output. Significant economic gains have been achieved by building improved nuclear reactors with outputs of about 3300 MW(th) and about 1000 conventionalfissiongaseskilowattsmaterialsMW-electricalneutronnuclearplantreactionswork [MW(e)].