Fuel fast-breeder reactor

Uranium produced from the uneconomic sources listed in Table 5.16 would cost several hundred dollars per pound and is not economic at present. If the uranium-fueled fast-breeder reactor becomes economic, it would generate so much electricity per ton of natural uranium that Chattanooga shale and even Conway granite irdght be used as economic uranium sources. These sources are estimated to contain 5 million and 6 to 9 million MT of uranium, respectively. Environmental problems from the large amount of earth disturbed in mining these low-grade sources would be severe. 

This again delays a decision about what to do with once or twice recycled LWR spent fuel either use it to fuel fast breeder reactors or dispose of MOX fuel in a repository. What is different, is that at least the HLW would contain no minor actinides. 

Fig. 11.1. Neutron spectra for small metal-fueled and large oxide-fueled fast breeder reactors [from T. D. Beynon, Rep. Prog. Phys. 37, 951 (1974). Copyright Institute of Physics].

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). 

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

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. 

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... 

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. 

Other newer designs include the advanced, gas-cooled reactor (AGR), Canadian deuterium reactor (CANDUR), sodium-cooled reactor (SCR), sodium-heated reactor (SHR), and fast breeder reactor (FBR). These reactors employ either natural or enriched uranium fuels that may be modified in some way (e.g., graphite-moderated fuels). 

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. 

Three of the Generation IV designs under consideration are fast breeder reactors The fast neutrons in the core have no moderator to slow them down. When these fast neutrons collide with fuel particles, they can generate more fuel. These reactors use gas, sodium or molten lead for cooling. 

In fast (neutron) reactors, the fission chain reaction is sustained by fast neutrons, unlike in thermal reactors. Thus, fast reactors require fuel that is relatively rich in fissile material highly enriched uranium (> 20%) or plutonium. As fast neutrons are desired, there is also the need to eliminate neutron moderators hence, certain liquid metals, such as sodium, are used for cooling instead of water. Fast reactors more deliberately use the 238U as well as the fissile 235U isotope used in most reactors. If designed to produce more plutonium than they consume, they are called fast-breeder reactors if they are net consumers of plutonium, they are called burners . 

FAME FAO FBR FC FCV FFV FOB FPFC Fatty acid methyl ester Food and Agriculture Organization of the United Nations Fast-breeder reactor Fuel cell Fuel-cell vehicle Flexible-fuel vehicle Free on board Fuel-processor fuel cell... 

Fuel type characteristics Graphite gaseous reactor Pressurized water reactor Fast breeder reactor... 

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 uranium. Fast neutrons are required to split plutonium. For this reason, water cannot be used in breeder reactors because 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 that it results... 

M. Levenson, J. V. C. Trice, and W. J. Mecham, Comparative Cost Study of the Processing of Oxide, Carbide, and Metal Fast Breeder Reactor Fuels by Aqueous,... 

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