Abstract: A method of immobilizing mixed low-level waste is provided which uses low cost materials and has a relatively long hardening period. The method includes: forming a mixture of iron oxide powders having ratios, in mass %, of FeO:Fe.sub.2 O.sub.3 :Fe.sub.3 O.sub.4 equal to 25-40:40-10:35-50, or weighing a definite amount of magnetite powder. Metallurgical cinder can also be used as the source of iron oxides. A solution of the orthophosphoric acid, or a solution of the orthophosphoric acid and ferric oxide, is formed and a powder phase of low-level waste and the mixture of iron oxide powders or cinder (or magnetite powder) is also formed. The acid solution is mixed with the powder phase to form a slurry with the ratio of components (mass %) of waste:iron oxide powders or magnetite:acid solution=30-60:15-10:55-30. The slurry is blended to form a homogeneous mixture which is cured at room temperature to form the final product.

Abstract: A method for forming a radiation-absorbing barrier around a radioactive component by flowing a radiation-absorbing cement grout into a container which encloses the component. The radiation-absorbing cement grout comprises a cement slurry, a finished foam material, a bentonite gel, and a radiation-absorbing metal constituent.

Abstract: A method for forming a radiation-absorbing barrier around a radioactive component by flowing a radiation-absorbing cement grout into a container which encloses the component. The radiation-absorbing cement grout comprises a cement slurry, a finished foam material, a bentonite gel, and a radiation-absorbing metal constituent.

Abstract: A process for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass.

Abstract: The invention is a process for direct conversion of solid radioactive waste, particularly spent nuclear fuel and its cladding, if any, into a solidified waste glass. A sacrificial metal oxide, dissolved in a glass bath, is used to oxidize elemental metal and any carbon values present in the waste as they are fed to the bath. Two different modes of operation are possible, depending on the sacrificial metal oxide employed. In the first mode, a regenerable sacrificial oxide, e.g., PbO, is employed, while the second mode features use of disposable oxides such as ferric oxide.

Abstract: A method of melting treatment of radioactive miscellaneous solid wastes containing therein an electrically conductive substance and other waste components. This method comprises charging the radioactive miscellaneous solid wastes into a cold crucible induction melting furnace provided with a high-frequency coil; supplying a high-frequency current to the high-frequency coil of the melting furnace to thereby heat and melt the electrically conductive substance, e.g. a metal, in the miscellaneous solid wastes; indirectly heating the other components in the miscellaneous solid wasted by utilizing the electrically conductive substance as a starting source of heating and melting; and placing the whole of the radioactive miscellaneous solid wastes into a molten state.

Abstract: Method for destroying radioactive graphite and silicon carbide in fuel elements containing small spheres of uranium oxide coated with silicon carbide in a graphite matrix, by treating the graphite fuel elements in a molten salt bath in the presence of air, the salt bath comprising molten sodium-based salts such as sodium carbonate and a small amount of sodium sulfate as catalyst, or calcium-based salts such as calcium chloride and a small amount of calcium sulfate as catalyst, while maintaining the salt bath in a temperature range of about 950.degree. to about 1,100.degree. C. As a further feature of the invention, large radioactive graphite fuel elements, e.g. of the above composition, can be processed to oxidize the graphite and silicon carbide, by introducing the fuel element into a reaction vessel having downwardly and inwardly sloping sides, the fuel element being of a size such that it is supported in the vessel at a point above the molten salt bath therein.

Abstract: A method and composition for stabilizing and isolating hazardous, radioactive or mixed waste materials of particulate and solid types, which comprises providing a non-toxic one component aqueous mixture of an acrylic polymer containing a thixotropic agent, a vinyl acetate-ethylene copolymer containing a thixotropic agent, or a vinyl chloride copolymer latex containing a thixotropic agent, and applying the mixture over surfaces of hazardous material in an amount sufficient to form a flexible impermeable coating or foam. The mixture may be applied by spraying to form a coating having a thickness of about 0.5 to about 5.0 centimeters when dry. The coated waste material may then be disposed of in conventional manner.