Fuel spent reactor

Nuclear Waste Reprocessing. Liquid waste remaining from processing of spent reactor fuel for military plutonium production is typically acidic and contains substantial transuranic residues. The cleanup of such waste in 1996 is a higher priority than military plutonium processing. Cleanup requires removal of long-Hved actinides from nitric or hydrochloric acid solutions. The transuranium extraction (Tmex) process has been developed for... 

Nuclear Waste. NRC defines high level radioactive waste to include (/) irradiated (spent) reactor fuel (2) Hquid waste resulting from the operation of the first cycle solvent extraction system, and the concentrated wastes from subsequent extraction cycles, in a faciHty for reprocessing irradiated reactor fuel and (3) soHds into which such Hquid wastes have been converted. Approximately 23,000 metric tons of spent nuclear fuel has been stored at commercial nuclear reactors as of 1991. This amount is expected to double by the year 2001. 

The solvent extraction process that uses TBP solutions to recover plutonium and uranium from irradiated nuclear fuels is called Purex (plutonium uranium extraction). The Purex process provides recovery of more than 99% of both uranium and plutonium with excellent decontamination of both elements from fission products. The Purex process is used worldwide to reprocess spent reactor fuel. During the last several decades, many variations of the Purex process have been developed and demonstrated on a plant scale. 

Typical Isotopic Composition op Plutonium in Spent Reactor Fuel ... 

Nuclear power plants use fuel rods with a life span of about three years. Each year, roughly one-third of spent fuel rods are removed and stored in cooling basins, either at the reactor site or elsewhere. Typical modern nuclear power plants discharge about 30 tons of the spent fuel per reactor per year. Comparatively little of Lite radioactive wastes, as is currently reliably known worldwide, has been processed for return to the fuel cycle. Actually, fuel reprocessing causes a net increase in the volume of radioactive wastes, but, as in the ease of military wastes, they are less hazardous in the long term. Nevertheless, the wastes from reprocessing also must be disposed of with great care. 

In the chemical reprocessing of spent reactor fuel, there are a number of possible applications of surface analysis techniques. Quite recent, XPS studies of dissolution mechanisms of UO2 fuel have begun. Studies in support of surface protection of dis-... 

Radioactive wastes of concern include wastes that result from operation of the nuclear fuel cycle (mining, fuel fabrication, reactor operation, spent fuel reprocessing, and waste storage), from nuclear weapons testing, and from medical and research activities. In recent years, the emphasis has been on predicting the behavior of disposed high-level wastes in deep geologic... 

In the United States and Russia, the most serious waste problem is radioactive and toxic material that has accumulated from weapons production during the Cold War years, closely followed by spent fuel from reactors. 

Radioactive waste containing uranium is usually grouped into three categories uranium mill tailings, low-level waste, and, in the case of spent reactor fuel, high-level waste. 

Gamma rays from spent reactor fuel rods were used for the photoreduction of the trivalent lanthanides. A spectral survey of these divalent containing crystals has been presented by McClure and Kiss (16). This photoreduction technique reduces only a minor fraction of the total trivalent concentration, and those divalent ions produced are unstable with respect to heat and/or light. Fong (3) has described these effects using divalent dysprosium as an example. 

Research on removal of noble gases by permeation method with dimethyl silicon membranes was carried out in Oak Ridge National Laboratory [160]. On the basis of experimental work, the calculations for different industrial cascades separating krypton and xenon from the space of molten salt and sodium cooled breeder reactor or from the off gas from a plant processing spent reactor fuel were performed. 

BLOMEKE AND BOND Oak Ridge National Laboratory SPENT REACTOR FUEL... 

The amount of radiation emitted varies with the particular compound, and a speck of some of these compounds can be very hazardous. However, the volume of wastes is not measured in specks, but in thousands of tons and millions of gallons. In one specific temporary storage facility, where almost 12 tons of spent reactor fuel rest in steel cylinders, the radiation can kill unprotected life in minutes (see Reference [1]). Further, it is estimated that high level nuclear wastes are now piling up at a rate of over 2000 tons per year. 

Irradiation. Samples were irradiated in the Argonne high level gamma irradiation facility. y-Rays, from spent reactor fuel elements, ranged in energy from 0.22 to 2.5 Mev., with an average of about 0.75 Mev. The dose rates for various samples varied from 1 X 104 to 4 X 104 rads per minute. The temperature of the samples was about 30 °C. 

The fuel processing operations to be used in conjunction with a nuclear power reactor and the amount of nuclear fuel that must be provided depend on the type of reactor and on the extent to which fissile and fertile constituents in spent fuel discharged from the reactor are to be recovered for reuse. Figures 1.10 and 1.11 outline representative fuel processing flow sheets for uranium-fueled thermal reactors generating 1000 MW of electricity, at a capacity factor of 80 percent. 

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