Engineering Geology of Radioactive Waste Disposal

Three possible methods for future waste disposal are now being investigated: fixation in or as solids, disposal into salt, and disposal into deep porous formations. The fixation methods now under investigation all involve heating the waste, are expensive, and are dangerous to the operators, but the solid product once formed would probably be no further hazard. Disposal into salt can be arranged by mining the salt through shafts, which is expensive and will require shaft maintenance. Alternatively, cavities can be dissolved in salt by pumping fresh water down wells, but either such cavities must be small, or their use must be restricted to the disposal of medium-level waste if they are not to overheat. Cavities in salt should provide safe storage, for salt is quite impermeable, but the use of salt as a structural material raises questions. Disposal through deep wells also appears to have serious limitations. The wastes will have to be filtered and diluted and perhaps treated to reduce corrosion of the disposal wells. Heatgeneration problems will prevent the disposal of fresh, high-level waste. However, the very large potential storage capacity of deep porous formations suggests that the method may be applicable for the very large amounts ofmore » waste that will eventually be produced. Recently an investigation has begun of the possibility of disposing of waste mixtures into shale by fracturing. The subject is controversial, and although the initial experiments look promising it will take much experience with low-level waste before the future of the method can be evaluated. (auth) O H4374 Flow curves were run on plastics with applied force of 2.5 to 15 tons. Thirteen adhesive formulations, cast into films, are being evaluated for tensile strength and elongation. Several epoxy-modified Adiprene-polyol systems catalyzed with ferric acetonate were evaluated for possible use as adhesives which cure rapidly at room temperature. The equipment for xenon purification and isotope separation by low-temperature distillation was improved. A computer program that was devised for an ideal cascade of gas centrifuges for uranium isotope separation was revised to include the effects of vsriable enrichment, flow rates, and total feed. Studies are being made to discover the cause of slow variations in the measured power output of radioactive samples. Techniques for vapor deposition of beryllium on plastic microfilms were investigated. The adsorption of trace radioelements evaporated to dryness on metal and glass surfaces is being studied. The half life of Ra/sup 223/ is being redetermined by microcalorimetry and alpha counting. Methods are being developed to determine the coincidence correction in proportional counters by following the decay of pure radioisotopes. Ways of determining traces of Ac/sup 227/ in Ra/ sup 223/ are being investigated. Studies are being made of the physical properties of plutonium-bearing materials. Phase studies were made of the Ce-Pu system by differential thermal analysis and metallographic studies. Rods of various diameters were fabricated from plutonium oxide and uranium oxide glasses. Lead-loaded Neoprene rubber gloves were tested to determine the general characteristics of the material. (M.C.G.)« less