Nuclear energy reactors

In addition to the use of dinitrogen tetroxide as an oxidizer in rocket propellant systems, and as a potential nitrating agent is is also used as a cooling liquid in nuclear energy reactors under the name of Nitrin [61). 

Nuclear Energy Reactors An uncontrolled fission chain reaction can be adapted to make an atomic bomb, but controlled fission can produce electric power more cleanly than can the combustion of coal. Like a coal-fired power plant, a nuclear power plant generates heat to produce steam, which turns a turbine attached to an electric generator. 

Not all of the 300 naturally occurring isotopes are stable. Unstable nuclei (protons and neutrons) spontaneously transform (decay) to achieve stability and are the radioactive materials syn. radionuclides or radioisotopes. Many other radioactive isotopes are made artificially by bombarding atoms with neutrons or charged particles in processes that occur in nuclear energy reactors and particle accelerators. As nuclei decay, they emit one of four types of radiation characteristic of the atom ... 

Thorium, uranium, and plutonium are well known for their role as the basic fuels (or sources of fuel) for the release of nuclear energy (5). The importance of the remainder of the actinide group Hes at present, for the most part, in the realm of pure research, but a number of practical appHcations are also known (6). The actinides present a storage-life problem in nuclear waste disposal and consideration is being given to separation methods for their recovery prior to disposal (see Waste treati nt, hazardous waste Nuclear reactors, waste managet nt). 

Gadolinium s extremely high cross section for thermal neutrons, 4.6 x 10 (46,000 bams) per atom, is the reason for its extensive use in the nuclear energy (see Nuclearreactors). It is used as a component of the fuel or control rods, where it acts as a consumable poison, a trap for neutrons in the reactor (39). 

Aircraft Reactors. As early as World War II, the U.S. Army Air Force considered the use of a nuclear reactor for the propulsion of aircraft (62—64). In 1946 the nuclear energy for propulsion of aircraft (NEPA) program was set up at Oak Ridge, under Fairchild Engine and Airplane Corporation. Basic theoretical and experimental studies were carried out. The emphasis was on materials. A high temperature reactor was built and operated successfiiUy. 

BWRf 6 General Description of a Boiling Water Reactor, General Electric Co., Nuclear Energy Group, San Jose, California, 1980. 

P. V. Evans, ed.. Fast Breeder Reactors, Proceedings of the London Conference on Past Breeder Reactors of the British Nuclear Energy Society, May... 

Directory of Nuclear Research Reactors, International Atomic Energy Agency, Vienna, Austria, 1989. 

In plutonium-fueled breeder power reactors, more plutonium is produced than is consumed (see Nuclearreactors, reactor types). Thus the utilisa tion of plutonium as a nuclear energy or weapon source is especially attractive to countries that do not have uranium-enrichment faciUties. The cost of a chemical reprocessing plant for plutonium production is much less than that of a uranium-235 enrichment plant (see Uranium and uranium compounds). Since the end of the Cold War, the potential surplus of Pu metal recovered from the dismantling of nuclear weapons has presented a large risk from a security standpoint. 

Nuclear (fission) reactors produce useful thermal energy from the fission (or disintegration) of isotopes such as and 94Pu . Fission of a heavy... 

The greatest concern that most members of the general public have about nuclear energy is the possibility of a catastrophic accident such as occurred in 1986 at Chernobyl in the Ukraine. If reactors have... 

The Atomic Energy Act of 1946 represented the interests of American scientists who wished to see nuclear energy developed for nonniilitai y purposes. It called for the establishment of a five-member civilian Atomic Energy Commission (AEC), which could deliver weapons to the military only on presidential order. But the militaiy tensions ot the early Cold War delayed civilian nuclear power development until 1948, at which time 80 percent of the AEC s budget went to militaiy ends. In 1951, U.S. civilian nuclear power development consisted of only a small experimental government (liquid metal) reactor in Idaho. 

The fuel in a nuclear fission reactor is generally "U atoms arranged appropriately in a reactor vessel. Neutrons instigate fission of nuclei ofatoms and liberate energy. The energy output may be controlled either by regulating the fuel and/or adjusting the neu-... 

Forsberg, C. W., and Weinberg, A. (1990). Advanced Reactors, Passive Safety, and Acceptance of Nuclear Energy. Annual Review of Energy 1 h 1.33-1. S2. 

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. 

An electricity-producing nuclear breeder reactor commissioned by the U.S. Atomic Energy Commission. 

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