Reactor, breeder

Breath freshener Breathing apparatus Bredimn [50924-49-7] Breeder reactors... 

Molten lithium fluoride is used in salt mixtures for an electrolyte in high temperature batteries (qv) (FLINAK) (20), and as a carrier in breeder reactors (FLIBE) (21) (see Nuclear reactors). 

Fig. 5. Radioactivity after shutdown per watt of thermal power for A, a Hquid-metal fast breeder reactor, and for a D—T fusion reactor made of various stmctural materials B, HT-9 ferritic steel C, V-15Cr-5Ti vanadium—chromium—titanium alloy and D, siUcon carbide, SiC, showing the million-fold advantage of SiC over steel a day after shutdown. The radioactivity level after shutdown is also given for E, a SiC fusion reactor using the neutron reduced...

The breeder reactor, which would produce and bum plutonium and gradually increase the inventory of fissionable material, requires reprocessing of nuclear fuel. As of 1995 only limited research and development was in progress on breeder reactors, mainly in France and Japan. 

Boron-10 has a natural abundance of 19.61 atomic % and a thermal neutron cross section of 3.837 x 10 m (3837 bams) as compared to the cross section of 5 x 10 m (0.005 bams). Boron-10 is used at 40—95 atomic % in safety devices and control rods of nuclear reactors. Its use is also intended for breeder-reactor control rods. 

A variation of the classical fuel cycle is the breeder cycle. Special breeder reactors are used to convert fertile isotopes iato fissile isotopes, which creates more fuel than is burned (see Nuclear reactors, reactor types). There are two viable breeder cycles U/ Pu, and Th/ U. The thorium fuels were, however, not ia use as of 1995. A breeder economy implies the existence of both breeder reactors that generate and nonbreeder reactors that consume the fissile material. The breeder reactor fuel cycle has been partially implemented ia France and the U.K. 

J. M. Leitnaker, M. L. Smith, md C. M. Fitzpatrick, Conversion of Uranium Nitrate to Ceramic Grade Oxidefor the Eight-Water Breeder Reactor Process Development, ORNL-4755, Oak Ridge National Laboratory, Oak Ridge, Term., 1972. 

Herein reactors are described in their most prominent appHcation, that of electric power. Eive distinctly different reactors, ie, pressurized water reactors, boiling water reactors, heavy water reactors, graphite reactors, and fast breeder reactors, are emphasized. A variety of other appHcations and types of reactors also exist. Whereas space does not permit identification of all of the reactors that have been built over the years, each contributed experience of processes and knowledge about the performance of materials, components, and systems. 

Full advantage of the neutron production by plutonium requires a fast reactor, in which neutrons remain at high energy. Cooling is provided by a hquid metal such as molten sodium or NaK, an alloy of sodium and potassium. The need for pressurization is avoided, but special care is required to prevent leaks that might result in a fire. A commonly used terminology is Hquid-metal fast-breeder reactor (LMFBR). 

The first experimental breeder reactor (EBR-1), which was the first reactor to generate electricity on a practical basis, went into operation in 1951 at the National Reactor Testing Station in Idaho. After the first reactor was damaged by a power excursion, EBR-11 was put into operation in 1961 (57). As of early 1995 it continued to operate very well. 

As a part of the power demonstration program of the AFC in the 1950s, the Enrico Fermi fast breeder reactor (Fermi-1) was built near Detroit by a consortium of companies led by Detroit Edison. Fermi-1 used enriched uranium as fuel and sodium as coolant, and produced 61 MWe. It suffered a partial fuel melting accident in 1966 as the result of a blockage of core coolant flow by a metal plate. The reactor was repaired but shut down permanently in November 1972 because of lack of binding. Valuable experience was gained from its operation, however (58). 

The United States continued fast-breeder reactor research and development with the building of the fast flux test faciHty (FFTF) at Hanford and the SEFOR reactor in Arkansas (59). The next plaimed step was to build a prototype power reactor, the Clinch River fast-breeder plant (CRFBP), which was to be located near Oak Ridge, Teimessee. 

Prospects in the United States for deploying breeders on a large scale were bright when it was beHeved that rich uranium ore would be quickly exhausted as use of nuclear power expanded. The expected demand for uranium was not realized, however. Moreover, the utiliza tion of breeders requires reprocessing (39). In 1979 a ban was placed on reprocessing in the United States. A dampening effect on development of that part of the fuel cycle for breeder reactors resulted. The CRFBP was canceled and France and Japan became leaders in breeder development. 

Fig. 11. Reactor core of MONJU, the Japanese fast-breeder reactor. Courtesy of Power Reactor and Nuclear Fuel Development Corp.

The only other fast-breeder reactors in operation in the world are the 233 MWe Phnnix in France, the 135 MWe BN-350 in Ka2akhstan, and the 560 MWe BN-600 Beloyarskiy in Russia. 

Fast Breeder Reactors" uader "Nuclear Reactors" ia ECT3rd ed., VoL 16, pp. 184—205, by P. Murray, Westiaghouse Electric Corp. 

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

The technologically most important isotope, Pu, has been produced in large quantities since 1944 from natural or partially enriched uranium in production reactors. This isotope is characterized by a high fission reaction cross section and is useful for fission weapons, as trigger for thermonuclear weapons, and as fuel for breeder reactors. A large future source of plutonium may be from fast-neutron breeder reactors. 

Uses of Plutonium. The fissile isotope Pu had its first use in fission weapons, beginning with the Trinity test at Alamogordo, New Mexico, on July 16, 1945, followed soon thereafter by the "Litde Boy" bomb dropped on Nagasaki on August 9, 1945. Its weapons use was extended as triggers for thermonuclear weapons. This isotope is produced in and consumed as fuel in breeder reactors. The short-Hved isotope Tu has been used in radioisotope electrical generators in unmanned space sateUites, lunar and interplanetary spaceships, heart pacemakers, and (as Tu—Be alloy) neutron sources (23). 

M. Levenson, J. V. C. Trice, and W. J. Mecham, Comparative Cost Study of the Processing of Oxide, Carbide, and MetalFast Breeder Reactor Fuels by Aqueous, Uolatility andPyrochemicalMethods, ANL-7137, Argonne National Laboratory, Argonne, lU., 1966. 

At high temperature, sodium and its fused haHdes are mutually soluble (14). The consolute temperatures and corresponding Na mol fractions are given in Table 3. Nitrogen is soluble in Hquid sodium to a limited extent, but sodium has been reported as a nitrogen-transfer medium in fast-breeder reactors (5) (see Nuclearreactors). 

Properties. Most of the alloys developed to date were intended for service as fuel cladding and other stmctural components in hquid-metal-cooled fast-breeder reactors. AHoy selection was based primarily on the following criteria corrosion resistance in Hquid metals, including lithium, sodium, and NaK, and a mixture of sodium and potassium strength ductihty, including fabricabihty and neutron considerations, including low absorption of fast neutrons as well as irradiation embrittlement and dimensional-variation effects. Alloys of greatest interest include V 80, Cr 15, Ti 5... 

When a fast-breeder reactor is shut down quickly, the temperature of the surface of a number of components drops from 600°C to 400°C in less than a second. These components are made of a stainless steel, and have a thick section, the bulk of which remains at the higher temperature for several seconds. The low-cycle fatigue life of the steel is described by... 

Department of Energy - has sponsored analyses of its reactors and process facilities, the risks of the breeder reactor, the risk of nuclear material transportation and disposal, and the risks of several fuel cycles. 

A fairly detailed risk analysis of fires was in the Clinch River Breeder Reactor (CRBR) Risk Assessment Study, 1977. In this study, FMEA was used to identify important fire locations for a wide variety of combustibles, including cables, oil, and sodium. The resulting estimate of the frequency of fire-induced core melt, 5E-7 per reactor-year, is substantially below the estimates discussed above. 

The CREDO data base contains data from The Fast Flux Test Facility in Richland, Washington, The Experimental Breeder Reactor - II in Idaho Falls, Idaho, The test loops of the Energy Technology Engineering Center (ETEC) in Canoga Park, California, The JOYO Liquid Metal Fast Breeder Reactor at the 0-Arai Engineering Center (OEC) in Japan, and the test loops of OEC. 

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