Energy nuclear fission

See also Nuclear Energy Nuclear Energy, Historical Evolution of the Use of Nuclear Fission Nuclear Fusion. 

See also Carnot, Nicolas Leonard Sadi Climatic Effects Engines Matter and Energy Nuclear Energy Nuclear Fission Refrigerators and Freezers Thermal Energy. 

See also Nuclear Energy Nuclear Fission Nuclear Fusion. 

See also Einstein, Albert Hydrogen Molecular Energy Nuclear Energy Nuclear Fission Nuclear Fusion Thermodynamics Units of Energy. 

See also Electric Power, Generation of Environmental Problems and Energy Use Explosives and Propellants Meitner, Lise Military Energy Use, Historical Aspects of Molecular Energy Nuclear Energy Nuclear Energy, Historical Evolution of the Use of Nuclear Fission Fuel Nuclear Fusion Nuclear Waste. 

Uranium is used as the primai-y source of nuclear energy in a nuclear reactor, although one-third to one-half of the power will be produced from plutonium before the power plant is refueled. Plutonium is created during the uranium fission cycle, and after being created will also fission, contributing heat to make steam in the nuclear power plant. These two nuclear fuels are discussed separately in order to explore their similarities and differences. Mixed oxide fuel, a combination of uranium and recovered plutonium, also has limited application in nuclear fuel, and will be briefly discussed. 

Plutonium-239 is a fissile element, and vvill split into fragments when struck by a neutron in the nuclear reactor. This makes Pu-239 similar to U-235, able to produce heat and sustain a controlled nuclear reaction inside the nuclear reactor. Nuclear power plants derive over one-third of their power output from the fission of Pu-239. Most of the uranium inside nuclear fuel is U-238. Only a small fraction is the fissile U-235. Over the life cycle of the nuclear fuel, the U-238 changes into Pu-239, which continues to provide nuclear energy to generate electricity. 

If we wish to gain some idea of the alteration of mass in a nuclear change, we cannot use the fission reaction because the exact masses of the nuclei involved are not known. Let us look at another type of reaction of possible importance in the production of nuclear energy ... 

Nuclear energy can be extracted by arranging for a nuclear chain reaction to take place in a critical mass of fissionable material. with neutrons as the chain carriers. A moderator is used to reduce the speeds of the neutrons in a reactor that uses fissile material. 

Nuclear energy in almost inconceivable quantities can be obtained from nuclear fission and fusion reactions according to Einstein s famous equation. 

Fissile materials are defined as materials that are fissionable by nentrons with zero kinetic energy. In nuclear engineering, a fissile material is one that is capable of snstaining a chain reaction of nuclear fission Nuclear power reactors are mainly fueled with manium, the heaviest element that occurs in natnre in more than trace qnantities. The principal nuclear energy soiuces are maninm-235, plutonium-239, uranium-233 and thorium. 

Baestle, L. H., Wakabayashi, T. Sakurai, S. 1999. Status and assessment report on actinide and fission product partitioning and transmutation, an OECD Nuclear Energy Agency review. In Proceedings of the International Conference on Future Nuclear Systems Global 99 Nuclear Technology - Bridging the Millenia , Jackson Hole, CD-ROM. 

Fission Reaction. See Vol 1, p A501-L, under Atomic (or Nuclear) Energy... 

Edward Teller, one of the brilliant physicists who fied Hungary before the war and a key member of the Los Alamos team, had no doubts about the right course of action. He urged the US government to pursue the idea he had discussed with Fermi in 1942 a superbomb that liberated nuclear energy not by fission but by fusion. The fusion bomb creates, for a blinding instant, an artificial sun. 

The fourth method of generation of energy is nuclear. Nuclear energy may be generated by die fission (splitting) of the atoms of certain elements and by the fusion (or joining together) of the nuclei of certain elements. 

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