Abstract: A process for producing high sinter density UO2 powder from UO2-containing scrap powder material, wherein the scrap material is oxidized at low temperature and the resulting U3O8 powder is reduced at a higher temperature which is than about to 800° C. to produce UO2 having high sinter density and high surface area.

Abstract: This invention provides an improved process of preparing UO.sub.2 powder from poor quality, partially oxidized powder containing organic and inorganic impurities. The process is illustrated in the flow chart of FIG. 1 which includes the steps of (a) oxidizing a uranium-containing scrap also containing inorganic and cationic organic impurities; (b) solubilizing, typically with nitric acid, the uranium contained in the oxidized scrap to produce uranyl nitrate; (c) solvent extracting the solubilized product of step (b) to remove cation impurities to provide a purified uranyl nitrate solution; (d) precipitating the purified uranyl nitrate with ammonia to form ammonium diuranate powder; and (e) calcining and passivating the ammonium diuranate powder to produce UO.sub.2 powder; and optionally (f) forming the UO.sub.2 powder of step (e) into pellets and sintering the formed pellets to produce sintered UO.sub.2 pellets.

Abstract: Technetium-99 is quantitatively determined in samples containing uranium using extraction chromatography to remove uranium which otherwise interferes in detecting technetium-99 in low concentrations.

Abstract: A process for reclaiming scrap UO.sub.2 materials yields a high-sinter-density pellet. The scrap is oxidized in a high-temperature furnace to produce U.sub.3 O.sub.8. The U.sub.3 O.sub.8 particles from the oxidation furnace are reacted with nitric acid to produce a solution of uranyl nitrate that meets the concentration and free acid requirements of the ADU precipitation process. A controlled two-stage ADU precipitation process is carried out to produce ADU particles with a size and morphology that leads to high-surface-area UO.sub.2 powder with excellent sintered pellet ceramic characteristics. After calcination and hydrogen reduction to UO.sub.2, the high-surface-area UO.sub.2 powder is passivated.

Abstract: The present invention relates to a process of decontaminating zirconium-based alloy claddings tubes used in nuclear reactor fuel rods. The process involved the use of a permanganate in a dilute acid solution. The process renders the alloy suitable for uncontrolled release into a non-radioactive environment.

Abstract: A safe analytical technique for determining the concentration amount of dibutyl and monobutyl phosphate degradation products in the TBP-dodecane solvent used in solvent extraction processes. This method of chemical analysis eliminates the use of diazomethane, which is toxic and explosive, thereby providing a safer laboratory technique for routine analyses required to monitor production solvent extraction processes. The solvent sample to be analyzed is spiked with mass labelled, deuterated dibutyl and monobutyl phosphates, which act as internal standards. After adding a silylating agent, bistrimethylsilyltrifluoracetamide, the sample is injected into a gas chromatograph/mass spectrometer, which measures the ratio between the labelled internal standard and the naturally occurring material to obtain a quantitative result.

Abstract: An improved internal standard for use in determining the concentration of decomposition products of tributyl phosphate in solvent used for solvent extraction. The improved internal standard includes deuterated variants of the decomposition products to be measured, e.g., deuterated dibutyl and monobutyl phosphoric acids. The use of deuterated dibutyl and monobutyl phosphoric acids eliminates the use of diazomethane, which is toxic and explosive, thereby providing a safer laboratory technique for routine analyses required to monitor production solvent extraction processes.

Abstract: An apparatus for solvent extraction processes utilizing countercurrent flow of streams of an aqueous phase and an organic phase, such as the Purex process for uranium recovery. The invention comprises contouring the fluid passing orifices in the column phase dispersing perforated plates to impede droplet coalescence of the dispersed phase.

Abstract: A method of passivating the surface of particulate uranium oxides is disclosed comprising a process of continuously contacting uranium oxide particles with an oxygen containing and cooling counter flowing gas stream. The treatment produces a protective surface which inhibits subsequent oxygen chemisorption of the particulate uranium oxides.

Abstract: A process for controlling the oxidation reaction of oxides of uranium and fixing the ratio of oxygen to uranium in uranium oxide compounds by means of a passification process, and the stabilized uranium oxide compounds produced therefrom. The method is especially useful in the production of uranium oxide fuel for nuclear reactors.

Abstract: A fugitive binder composition for compression molding uranium dioxide nuclear fuel comprising the reaction product of a strongly alkali water solution of a diamine and oxalate ions with uranium oxide which is free of carbonates and carbamates, and having the formula:[.sup.+ NH.sub.3 (CH.sub.2).sub.2 NH.sub.3.sup.+ ][UO.sub.2 (C.sub.2 O.sub.4).sub.2 (H.sub.2 O).sub.2 ][.sup.+ NH.sub.3 (CH.sub.2).sub.2 NH.sub.3.sup.+ ].

Abstract: A method and binder composition for prolonging the induced plasticity of a particulate ceramic material admixture comprising uranium dioxide and a fugitive binder, and product thereof, for subsequent compaction by compression molding in the manufacture of nuclear fuel pellets. The fugitive binder comprises a reaction product of an amine carbonate or amine carbamate and ammonium oxalate reacted with uranium dioxide at a temperature of at least 65.degree. C. The uranyl oxalate-carbonate reaction product has the composition of (UO.sub.2 (CO.sub.3) (C.sub.2 O.sub.4). 2H.sub.2 O). 2H.sub.2 O.

Abstract: A reproducible method and stable binder composition for preserving the induced plasticity of a particulate ceramic material admixture comprising uranium dioxide and a fugitive binder, and product thereof, for subsequent compaction by compressing molding in the manufacture of nuclear fuel pellets.

Abstract: An improved method for compression molding of typically brittle ceramic materials comprising uranium dioxide which enhances their compacting and cohering properties in the manufacture of nuclear fuel products. The uranium dioxide is mixed with a fugitive binder comprising a high molecular weight acrylic acid polymer and ammonium bicarbonate. The mixture is then pressed and sintered to expel the binder and to give a fissionable nuclear fuel pellet.

Abstract: A method and apparatus for the introduction of second cohesive powders into an improved fluidized bed blender containing UO.sub.2 powder, and for blending such second cohesive powders with the UO.sub.2 powder in the fluidized bed blender. The apparatus comprises an eductor, an improved pressurized vortec mill, a pneumatic conveying system that operates in turbulent flow, and an improved fluidized bed blender. The method and apparatus provide for injection and uniform dispersion of a second cohesive powdered ingredient or ingredients having hydrophobic, hydrophilic or hygroscopic properties in the fluid bed blender adjacent the bottom of the fluidized bed therein during the blending operation, thereby minimizing entrainment of the second powder mixture and providing a homogeneous blend of powders.

Abstract: A process for imparting increased strength and physical durability in green bodies or pellets formed of particulate oxides of uranium, plutonium and the like in the production of pelletized fissionable nuclear fuel. The green or unfired pellets comprise a fugitive binder dispersed through the particulate oxide fuel material.

Abstract: A critically safe container for the storage and rapid discharge of enriched nuclear fuel material in powder form is disclosed. The container has a hollow, slab-shaped container body that has one critically safe dimension. A powder inlet is provided on one side wall of the body adjacent to a corner thereof and a powder discharge port is provided at another corner of the body approximately diagonal the powder inlet. Gas plenum for moving the powder during discharge are located along the side walls of the container adjacent the discharge port.

Abstract: A metering method and apparatus is provided for the controlled discharge of powder from a fluidized-bed blender to a material container, which gives accurate material weights while separating powder from fluidizing gas. In this method the material container is filled with a series of short duration discharges at a reduced powder flow rate. This method enables the apparatus to more precisely measure the weight of the container and maintain homogeneity of the blended material in both the bed and the container. The apparatus for carrying out this method includes a flexible pressure-tight sleeve connecting the fluidized bed to the container. When a ball valve located at the bottom of the fluidized bed opens to discharge powder, the sleeve retains the high pressure fluidizing gas inside the sleeve and the container. This causes the pressure to build at the outlet of the valve thus preventing the gas from rapidly exhausting and forcing powder through the outlet.

Abstract: A mixture of fine and cohesive powders is blended to complete homogeneity in a nuclear-safe bubbling-bed fluidized bed blender having an improved fluidizing grid. The blender includes a generally vertically-oriented slab-shaped, nuclear-safe mixing vessel having a fluidizing grid disposed at one end of the vessel. The fluidizing grid comprises a linear array of generally downwardly-directed, pyramidal-shaped hoppers each having walls converging into a conically-shaped opening. A plurality of ball valves are employed, one such valve being disposed at the bottom of each hopper. The rotary closure member of each of the ball valves includes a first set of gas orifices for directing a flow of fluidizing gas upwardly in a divergent swirl-shaped pattern along the walls of each of the hoppers. In one embodiment a second set of fluidizing gas orifices for directing a flow of fluidizing gas downwardly into the apex of each of the hoppers is also provided.