Nuclear fuels fast-breeder reactor

Yb-169 Used during brain scans U-235 Fuel for most nuclear reactors Pu-239 Used in nuclear weapons, fast breeder reactors, and MOX fuel reactors Am-241 Used in smoke detectors... 

The amount of U-235 present in a nuclear fuel rod is gradually depleted, and ultimately there is insufficient present for the economic generation of power. A fast-breeder reactor uses the interaction of U-238 with energetic (fast) neutrons to generate the plutonium isotope Pu-239. As Pu-239 can be used as a nuclear fuel, a breeder reactor produces more fuel than it consumes. The sequence of steps is ... 

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

Many of the fission products formed in a nuclear reactor are themselves strong neutron absorbers (i.e. poisons ) and so will stop the chain reaction before all the (and Pu which has also been formed) has been consumed. If this wastage is to be avoided the irradiated fuel elements must be removed periodically and the fission products separated from the remaining uranium and the plutonijjm. Such reprocessing is of course inherent in the operation of fast-breeder reactors, but whether or not it is used for thermal reactors depends on economic and political factors. Reprocessing is currently undertaken in the UK, France and Russia but is not considered to be economic in the USA. 

The phrase "nuclear power" covers a number of technologies for producing electric power other than by burning a fossil fuel. Nuclear fission in pressurized water-moderated reactors—light water reactors— represents the enrrent teehnology for nuclear power. Down the line are fast breeder reactors. On the distant horizon is nnclear fusion. 

I0.6.8.I Cladding failure in oxide fuel pins of nuclear reactors. The long-term operational performance of nuclear fuel pins is critically governed by the reactions that occur in the gap between the fuel and its cladding. Ball et al. (1989) examined this for the cases of (1) Zircaloy-clad pellets of U02+, in a pressurised water reactor (PWR) and (2) stainless-steel-clad pellets of (U, P)02+, in a liquid-metal-cooled fast-breeder reactor (LMFBR). In particular they were interested in the influence of O potential on Cs, I, Te and Mo and the effects of irradiation on the gaseous species within the fuel-clad gaps. 

The plutonium fuel in a breeder reactor behaves differently than does uranium. Fast neutrons are required to split plutonium. For this reason water cannot be used in breeder reactors, as it moderates the neutrons. Liquid sodium is typically used in breeder reactors, and the term liquid metal fast breeder reactor (LMFBR) is used to describe it. One of the controversies associated with the breeder reactor is the production of weapon-grade plutonium and nuclear arms proliferation. 

Pu02 is also well suited as a nuclear fuel. It is often used in the form of a UO2/ PUO2 mixture ( mixed oxides MOX) containing up to about 20% PUO2. UO2/ PUO2 mixtures may be applied in thermal reactors instead of enriched uranium, or in fast breeder reactors. Pellets of Th02 can be used in thermal converters for production of... 

The projections are based on a recent forecast (Case B) by the Energy Research and Development Administration (ERDA) of nuclear power growth in the United States (2) and on fuel mass-flow data developed for light water reactors fueled with uranium (LWR-U) or mixed uranium and plutonium oxide (LWR-Pu), a high temperature gas-cooled reactor (HTGR), and two liquid-metal-cooled fast breeder reactors (LMFBRs). Nuclear characteristics of the fuels and wastes were calculated using the computer code ORIGEN (3). 

E.C. Norman, ed., Fast Breeder Reactor Fuel Performance, Proc. Int. Conf, March 5-8, 1979, Monterey, CA American Nuclear Society, La Grange, IL, 1979. 

Steunenberg, R. K. Pierce, R. D. Johnson, I., "Status of the Salt Transport Process for Fast Breeder Reactor Fuels," in "Symposium on Reprocessing of Nuclear Fuels, The Metallurgical Society of AIME, Ames, IA, August 1969," Nucl. Metallurgy,... 

For future nuclear energy production, considerable promise is held out by the fast breeder reactor techniques used to produce fissional materials from non-fissional ones. There is the corresponding problem of substantially increasing the levels of nuclear wastes that must be handled in such a way as to render them as harmless as possible to the environment. In this area of processing of nuclear fuels, ion-exchange techniques again are useful. After the production of 233U via the reaction ... 

In the current structure of nuclear power, light water reactors (LWRs) are predominant over a small number of heavy water reactors (HWRs), and even smaller number of fast breeder reactors (FBRs). However, an increase of FBR share can be predicted for the future, taking into account their unique properties. First of all, there is the capability of nuclear fuel breeding by involving into the fuel cycle. Secondly, there is the fast reactor s flexibility permitting its use as plutonium incinerators and minor actinides transmutation. Thus, unless new sources of energy are found, the development of nuclear power will be necessarily based on fast breeder reactors. 

Even a change to nuclear energy would help, since the overall cost of the raw material—the uranium ore—would be smaller due to the much smaller quantities required, and the security of supply should be less of a problem since the ore occurs throughout the world, particularly in North America, Southern Africa, Australia and Sweden. The much higher capital costs for the nuclear power station are an important factor which has to be taken into consideration. Prototype fast-breeder reactors have been operated in the U.K. for some years now and when fully developed they could substantially improve the economics of nuclear energy. This is because they enable more energy to be extracted from waste uranium and in addition utilize the plutonium produced in conventional reactors as fuel. 

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