Abstract: By using AVLIS or other methods capable of providing a depleted isotopic mixture, troublesome isotopes such as Gd.sup.154, Gd.sup.156 and Er.sup.166 are selectively removed from naturally occurring isotopic mixtures, while avoiding the additional costs associated with complete fractionation of the mixture. Such mixtures can be used to provide a burnable nuclear fuel absorber having a selectively depleted isotope or isotopes. In particular, the invention concerns burnable absorbers containing erbium with a depleted 166 isotope, gadolinium with a depleted 156 isotope or with depleted 154 and 156 isotopes, and methods for making such absorbers.

Abstract: A zirconium alloy absorber material is described which can be used in structural components in light water nuclear reactors. The zirconium alloy absorber material includes a zirconium alloy material, such as Zircaloy-2 or Zircaloy-4, which has been modified by the addition of isotopically pure erbium-167 in an amount ranging from about 0.1 to about 0.4 wt. %, and preferably about 0.2 wt. %.

Abstract: By using AVLIS or other methods capable of providing a depleted isotopic mixture, troublesome isotopes such as Gd.sup.154, Gd.sup.156 and Er.sup.166 are selectively removed from naturally occurring isotopic mixtures, while avoiding the additional costs associated with complete fractionation of the mixture. Such mixtures can be used to provide a burnable nuclear fuel absorber having a selectively depleted isotope or isotopes. In particular, the invention concerns burnable absorbers containing erbium with a depleted 166 isotope, gadolinium with a depleted 156 isotope or with depleted 154 and 156 isotopes, and methods for making such absorbers.

Abstract: Radiation detectors measuring gamma radiation from radioactive accumulations in an incinerator through low density refractory windows therein for burning combustible, contaminated wastes from nuclear fuel manufacturing activities.

Abstract: A method and system for quality control of nuclear fuel materials, said system including amplifier/integrator circuitry, signal processors, and drift control feedback circuitry. The invention permits the qualitative and quantitative measurement of paramagnetic additives such as gadolinium for example in a paramagnetic base nuclear fuel material including ferromagnetic impurities. Drift problems relating to temperature and other effects are solved electrically and mechanically. Analysis can be conducted irrespective of the form or composition of the nuclear fuel.

Abstract: An automated inspection station comprises a pair of rotating rollers for supporting a collected group of pellets. A pusher drops in behind the group to urge the entire group forward. The rotating rollers cause the entire group of pellets to spin in unison as the pellets pass through an optical inspection station. The optical inspection station comprises a light source, diverging and collimating lenses to illuminate each rotating pellet in turn. Signals are generated by at least two arrays of photodiodes in response to light reflected from the surface of the pellets. Circuitry normalizes the signals of the respective diodes for variations unrelated to pellet surface features. The signals are analyzed to ascertain conformance of each pellet to length, cylindricality diameter and surface reflectivity requirements. A pellet sorter diverts unacceptable pellets from the path, while the acceptable pellets are transported to a collection station.

Abstract: Method and apparatus for the nondestructive determination of the amount and quantitative distribution of a paramagnetic additive such as gadolinia in nuclear fuel elements. Changes in paramagnetic susceptibility of the material in the element are detected as the element is passed through a constant magnetic field and compared to the changes in susceptibility produced by a standard element of known additive content.

Abstract: The amount of fissile material such as U-235 in each portion of a fuel element, some of which portions may also contain burnable poison such as gadolinium, is determined by detecting the gamma ray emission due to the natural radioactive decay of the fuel material, analyzing the gamma ray signals from each portion to provide a first count of gamma rays primarily due to the U-235 and a second count of gamma rays primarily due to the U-238 daughter products. These first and second counts are corrected for the cladding wall thickness, the density of the fuel material and the burnable poison content in each portion. The first (U-235) count is then corrected by the second (U-238 daughter) count and the thus corrected U-235 count is converted to an indication of the fuel enrichment in each portion. From the enrichment, the burnable poison content, the density of the fuel material and the volumes of each portion, the weight of U-235 in each portion can be determined.

Abstract: Alloys reacting with water, water vapor and reactive gases at temperatures in the range of about 200.degree. to about 650.degree. C. have the essential components of nickel, titanium and zirconium. The alloys can be made by arc melting zirconium, nickel and titanium and can be formed into sheet or foil by inert-atmosphere hot rolling. The alloys can also be made by plating nickel on a sheet of zirconium-titanium alloy and then conducting a diffusion process by heating the plated alloy in vacuum.

Abstract: A nuclear fuel cell for use in a thermionic nuclear reactor in which a small conduit extends from the outside surface of the emitter to the center of the fuel mass of the emitter body to permit escape of volatile and gaseous fission products collected in the center thereof by virtue of molecular migration of the gases to the hotter region of the fuel.

Abstract: A method and apparatus for magnetically determining the Gd.sub.2 O.sub.3 content in UO.sub.2 fuel pellets is described. The alternating current susceptibility of fuel pellets within a zircalloy cladding is measured using an ac inductive technique. Ferromagnetic impurity moments are saturated with a direct current magnetic field. Susceptibility increases with increasing Gd.sub.2 O.sub.3 content when the ferromagnetic component is saturated in fields above 6 kOe.

Abstract: Alloys reacting with water, water vapor and reactive gases at temperatures in the range of about 200.degree. to about 650.degree. C have essential components of nickel, titanium an zirconium. The alloys can be made by arc melting zirconium, nickel and titanium and can be formed into sheet or foil by inert-atmosphere hot rolling. The alloys can also be made by plating nickel on a sheet of zirconium-titanium alloy and then conduction a diffusion process by heating the plated alloy in vacuum.

Abstract: A process for polishing surfaces of sapphire or similar materials to remove surface imperfections visible at magnifications of 1,000X or higher regardless of the shape of the surface, is disclosed, which process comprises the steps of heating the material to an elevated temperature and exposing the surface to be polished to a static hydrogen environment.

Abstract: Process for dehalogenation of particulate compositions containing halide impurities including metallic oxides and metallic halides such as metallic fluorides to produce metallic oxides by contacting the compositions in a heated atmosphere containing vaporized alcohol. A second gas including inert gases and active dehalogenating gases can be mixed with the vaporized alcohol. A preferred practice has agitation of the particulate compositions containing halide impurities during the dehalogenation process. The metallic oxide produced by dehalogenation can be freed from any hydrocarbon residues where desired by a subsequent heating step in a reducing atmosphere. The halide ions from the dehalogenation can be recovered as an acid by passing the dehalogenation atmosphere through water. A preferred practice of this invention uses propyl alcohol as no hydrocarbon residues are found in the dehalogenated powder.