Abstract: Described herein is a composite nuclear fuel rod cladding tube which includes two concentric layers of zirconium base alloys metallurgically bonded to each other. The outer layer is composed of a conventional zirconium base alloy having high strength and excellent aqueous corrosion resistance. The inner layer is composed of a second zirconium base alloy containing about 0.2 to 0.6 wt. % tin, about 0.03 to 0.11 wt. % iron and up to about 350 ppm oxygen. This second alloy while also having excellent aqueous corrosion resistance, is further characterized by the ability to prevent the propagation of cracks initiated during reactor operation due to pellet-cladding interaction.

Abstract: Process for the preparation of the surface of a uranium or uranium alloy part. It comprises a stage of chemically etching the surface of the uranium or uranium alloy part by means of a solution of nickel chloride and hydrochloric acid. The etching solution may also contain hydrofluoric acid.The nickel-coated uranium or uranium alloy parts can be used as shielding or ballasting members in a marine atmosphere.

Abstract: Substantially isotropic spherical fuel and absorber elements for high temperature reactors are produced by molding corresponding fuel particles and graphite molding compositions. There is used as graphite molding powder a mixture of graphitized granules of coke and a hardenable resin binder. There are first produced in steel dies at 80.degree. to 120.degree. C. half shells and a nucleus with a pressed density of 1.0 to 1.4 g/cm.sup.3 followed by molding in a further steel die to the final format.

Abstract: To produce spherical fuel or absorber elements for high temperature reactors a mixture of coated nuclear fuel or absorber particles and graphite molding composition is molded into spheres, carbonized in a furnace having gas flushing and calcined in a vacuum. There are attained high throughputs without addition of transportation aides by employing as resin binders a thermosetting synthetic resin, hardening the resin at 110.degree. to 170.degree. C. and subsequently allowing the spheres to roll for 1 to 10 hours through an oven which is inclined around 2.degree. to 12.degree. to the horizontal. Thereby the oven must exhibit an increasing and decreasing temperature profile, the flushing gas introduced from both sides and be removed in a temperature zone of 400.degree. to 500.degree. C.

Abstract: The present invention pertains to zirconium base alloys containing about 0.1 to 0.6 weight percent tin; about 0.07 to 0.24 weight percent iron; about 0.05 to 0.15 weight percent chromium; and up to about 0.05 weight percent nickel. The balance of the alloy is zirconium with incidental impurities. The levels of the incidental impurity, oxygen, is controlled to a level of less than about 350 ppm. These alloys have been designed to minimize the adverse effects of pellet-clad interaction, when they are used as a liner bonded to the inside surface of water reactor nuclear fuel cladding. Specific cladding and fuel element designs according to the present invention are described.

Abstract: Process for the conditioning of waste, such as radioactive or toxic waste, whose acidity can inhibit polymerization reactions, e.g. waste containing cation exchange materials.This process consists of incorporating the waste into a liquid epoxy resin at ambient temperature and then bringing about the polymerization of the resin by means of a hardener, in order to obtain a solid block.A hardener containing at least one compound having at least one NH.sub.2 group in an adequate quantity for blocking the active sites of the cation exchange materials present in the waste or for neutralizing the acidity of the humid waste and for polymerizing the epoxy resin is used.This process can be more particularly used for conditioning resin beds used for the purification of the water of nuclear power stations.

Abstract: A process for the production of depleted uranium metal particles comprising heating depleted uranium metal to red heat, rapidly chilling the heated metal, grinding the resulting brittlized metal to form powder size particles, annealing the particles and coating the particles with silver, copper, or lead, wherein the grinding and annealing are carried out in an inert argon atmosphere. The invention also contemplates the resulting depleted uranium metal powder, compositions containing the same as well as the liners for shaped charges formed therefrom.

Abstract: A method for coating a nuclear fuel with a burnable poison and a burnable poison coated nuclear fuel made by the method. The nuclear fuel is surface cleaned, and then a burnable poison layer is sputtered thereon. A sputtering deposition rate is picked that preferably will heat the nuclear fuel surface between 200.degree. C. and 600.degree. C. For deposition rates that result in heating the nuclear fuel surface to less than 200.degree. C., external heat is applied to heat the nuclear fuel surface between 200.degree. C. and 600.degree. C. To make the burnable poison layer less hygroscopic, an overcoat layer of a hydrophobic material is sputtered on the burnable poison layer.

Abstract: A method for coating a uranium dioxide nuclear fuel with a zirconium diboride burnable poison. First, a layer of niobium is bonded to the nuclear fuel. Then, a layer of zirconium diboride is deposited by chemical vapor deposition on the niobium layer. A zirconium diboride coated nuclear fuel having a layer of niobium between a uranium dioxide substrate and the zirconium diboride layer also is disclosed.

Abstract: A method of applying a burnable absorber coating on a nuclear fuel pellet comprising the step of exposing the nuclear fuel pellet to a gas stream of boron trichloride and anhydrous ammonia at a temperature of from about 600.degree.-800.degree. C. A coating of boron nitride is formed as a reaction product of boron trichloride with anhydrous ammonia on the fuel pellet.

Abstract: A fluidized bed furnace for coating fuel particles for nuclear reactors, ticularly high temperature reactors, can be emptied without cooling down the reaction tube by substituting an inert gas for the coating gas and then lowering the inner tube through which this gas is fed so as to clear a passage in the surrounding outer gas feed tube through which the kernels may fall down to a diverting device in the intermediate space between the inner and outer tubes that guides the kernels to a discharge tube. The reaction tube is emptied by lowering the feed gas pressure by cutting off the carrier gas flow and regulating the escape of the inert gas through an overflow pipe. After the reactor is emptied, the flow of carrier gas can be restored and the overflow pipe shut, so that the reactor can be refilled, after which the flow of coating gas is restored and another coating operation can begin without delay.

Abstract: A method of fabricating multishell fuel targets for inertial confinement fusion usage. Sacrificial hemispherical molds encapsulate a concentric fuel pellet which is positioned by fiber nets stretched tautly across each hemispherical mold section. The fiber ends of the net protrude outwardly beyond the mold surfaces. The joint between the sacrificial hemispheres is smoothed. A ceramic or glass cover is then deposited about the finished mold surfaces to produce an inner spherical surface having continuously smooth surface configuration. The sacrificial mold is removed by gaseous reaction accomplished through the porous ceramic cover prior to enclosing of the outer sphere by addition of an outer coating. The multishell target comprises the inner fuel pellet concentrically arranged within a surrounding coated cover or shell by fiber nets imbedded within the cover material.

Abstract: An improved method and apparatus are given for producing cryogenic inertially driven fusion targets in the fast isothermal freezing (FIF) method. Improved coupling efficiency and greater availability of volume near the target for diagnostic purposes and for fusion driver beam propagation result. Other embodiments include a new electrical switch and a new explosive detonator, all embodiments making use of a purposeful heating by means of optical fibers.

Abstract: A small object (12, FIG. 2) is coated by holding it in the pressure well (20) of an acoustic standing wave pattern, and then applying a mist of liquid coating material (42) at low velocity into the pressure well. The pressure gradient within the well forces the mist particles to be pushed against the object. A lower frequency acoustic wave (for oscillator 28, FIG. 4) also can be applied to the coated object, to vibrate it so as to evenly distribute the coated material. The same lower frequency vibrations can be applied to an object in the shape of a hollow sphere, to center the inner and outer surfaces of the sphere while it remains suspended.

Abstract: For certain related dimensions of features of a nozzle feeding a fluidized bed reactor from below, it has been found that a central flow of a coating gas is squeezed down in diameter in passing through a constriction at the nozzle end by the action of the surrounding dilution gas flow, without the setting up of turbulence such as might have been expected, which would cause deposits from the decomposition of the coating gas at the constriction. The spacing between the mouth of the central tube that feeds the coating gas and the constriction at the end of the nozzle should be in the range of 20 to 70 mm, the diameter of the constriction aperture should be in the range from 3 to 10 mm and the diameter of the central channel should be greater than the constriction aperture diameter but not more than 3.5 times the latter diameter. For coating particles having a density of about 10 g/m.sup.3 and a diameter of about 200 .mu.m , the constriction aperture diameter should not exceed 7 mm.

Abstract: Very smooth polymeric coatings or films graded in atomic number and density can readily be formed by first preparing the coating or film from the desired monomeric material and then contacting it with a fluid containing a metal or a mixture of metals for a time sufficient for such metal or metals to sorb and diffuse into the coating or film. Metal resinate solutions are particularly advantageous for this purpose. A metallic coating can in turn be produced on the metal-loaded film or coating by exposing it to a low pressure plasma of air, oxygen, or nitrous oxide. The process permits a metallic coating to be formed on a heat sensitive substrate without the use of elevated temperatures.

Abstract: A fluidized bed furnace employed for depositing pyrolytic carbon or silicon carbide on nuclear fuel particles is supplied with an inert dilution gas and a decomposable coating gas. These are supplied by means of a gas injector having at least three pipes 4 for coating gas extending within a surrounding duct for a stream of dilution gas 6. This leads to a partition 2 at the base of the bed, having at least three apertures 3 for through passage of the gases.

Abstract: A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

Abstract: A method for producing a cesium-retentive waste form, characterized by a high degree of compositional stability and mechanical integrity, is provided by subjecting a cesium-loaded zeolite to heat under conditions suitable for stabilizing the zeolite and immobilizing the cesium, and coating said zeolite for sufficient duration within a suitable environment with at least one dense layer of pyrolytic carbon to seal therein said cesium to produce a final, cesium-bearing waste form. Typically, the zeolite is stabilized and the cesium immobilized in less than four hours by confinement within an air environment maintained at about 600.degree. C. Coatings are thereafter applied by confining the calcined zeolite within a coating environment comprising inert fluidizing and carbon donor gases maintained at 1,000.degree. C. for a suitable duration.

Abstract: In the process of applying a layer of copper and a layer of zirconium dioxide to the internal surface of a tube of a zirconium-based alloy, with the layer of zirconium dioxide being located between the copper layer and the internal surface of the tube, the tube surface is first treated with an activating solution in the form of an aqueous solution containing from about 1 to about 3 grams/liter of hydrogen fluoride, from about 2 to about 8 grams/liter of ammonium fluoride and from about 0.1 to about 0.5 gram/liter of sulfuric acid, the amounts of hydrogen fluoride and ammonium fluoride being chosen so that the amount of ammonium fluoride, calculated in moles, exceeds the amount of hydrogen fluoride, calculated in moles, by at least 5 percent.

Abstract: The reaction gas throughout of the supply duct feeding gas to the bottom of a fluidized bed reactor of the kind shown in U.S. Pat. No. 4,153,004, issued May 8, 1979, is increased by providing the reaction gas supply tube in the form of a bundle of tubes of small cross-section of about 2 mm diameter. Subdivision of the supply tube into hexagonal ducts in honeycomb arrangement maximizes the useful cross-sectional area of the supply tube. With the smaller elemental tube diameters, a higher rate of flow is maintainable without loss of laminar flow behavior, which behavior is maintained in the jet issuing from the subdivided reaction gas supply duct as it flows towards the constricted entrance into the fluidized bed container while being surrounded by a sheath of inert carrier gas supplied by an annular duct surrounding the reaction gas tube.

Abstract: A copper barrier type, nuclear fuel cladding is produced by forming an oxide layer on the inner wall surface of a tube of zirconium or zirconium alloy and then applying electroless copper plating to the oxide layer with a solution containing at least a copper salt, a complexing agent, a reducing agent, and 2,2'-dipyridyl, or further together with polyalkylene glycol as a plating solution. A good adhesiveness is obtained between the copper barrier layer and the oxide layer.

Abstract: Radioactive waste material, such as that resulting from radioactive weapons plant operation or from nuclear fuel reprocessing, in suitable form, such as radionuclide-containing oxide and/or oxyhydroxide and/or hydroxide particles, is held by a metal or metal "alloy" to an electrically conductive cathodic material upon which the metal or alloy is electrodeposited. In this way the radionuclide species including strontium and/or cesium, which are biologically extremely hazardous, are incorporated into a metal matrix held to a base and may be disposed of, as by underground storage, in such form, which is considered to be more resistant to dissolution by ground water and to damage by mechanical stresses arising from tectonic activity than are glasses or ceramics incorporating radionuclides.

Abstract: A new technique for producing uniform layers of solid DT on microballoon surfaces. Local heating of the target, typically by means of a focused laser, within an isothermal freezing cell containing a low pressure cryogenic exchange gas such as helium, vaporizes the DT fuel. Removal of the laser heating source causes the DT gas to rapidly condense and freeze in a layer which exhibits a good degree of uniformity.

Abstract: Smooth-surfaced, free-flowing, rigid, spherical, hollow microcapsules having non-porous shell walls consisting of essentially homogeneous, non-vitreous metal oxide in predominantly polycrystalline state, which have at least one shell having over the entire outer surface thereof one or more coatings of material of the class consisting of ceramic oxide, metal or pyrocarbon, which contain for storage and transport within said shell or shells preselected gases, solids or liquids suitable for use in fusion targets are described together with methods for their production.

Abstract: Fuel, fertile material and/or absorber material containing particles for fuel and/or absorber elements in nuclear reactors are coated by a process comprising introducing thermally cleavable gases in the reaction space heated to above 1000.degree. C. of a fluidized bed unit with the help of a gas inlet nozzle cooled with a cooling medium and having an elongated inlet tube, decomposiing the cleavable gases after leaving the nozzle, depositing the decomposition products on fuel, fertile material or absorber particles present in the fluidized bed and bringing these coated particles into fuel elements or absorber elements. The cooling medium is solely gaseous and only the portion of the inlet tube for the nozzle tips of the gas inlet nozzles within the axis are cooled and the heat glow penetrating from outside is reduced by heat insulation. An apparatus for carrying out the process is also described.

Abstract: A new technique for producing uniform layers of solid DT on microballoon surfaces. Local heating of the target, typically by means of a focused laser, within an isothermal freezing cell containing a low pressure cryogenic exchange gas such as helium, vaporizes the DT fuel contained within the microballoon. Removal of the laser heating source causes the DT gas to rapidly condense and freeze in a layer which exhibits a good degree of uniformity.

Abstract: A portion of the feed gas is supplied in a pulsating fashion to a fluidized ed reactor containing the articles to be coated mixed with fluidizing particles. The pulse frequency is between 1 and 10 Hz. A continuous flow of a portion of the total gas supply at a rate insufficient to produce turbulence in the bed is provided to facilitate control of the pulsing frequency and reduce the energy necessary for the pulsating gas stream. The gases fed to the reactor are a coating gas and a carrier gas, the flow containing the coating gas including a portion of the carrier gas. Either the pulsed flow or the continuous flow may consist entirely of carrier gas. The fluidizing particles are preferably of the same material as the articles to be coated and are typically of a grain size between 2 and 3 mm.

Abstract: A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

Abstract: A process of producing a material sensitive to an electromagnetic and corpuscular radiation involves successively depositing, onto a transparent substrate, a layer of a semiconductor, a barrier layer inert to the semiconductor layer and a layer of a metal capable of reacting with the semiconductor layer under the effect of the electromagnetic and corpuscular radiation with the formation of the reaction products. After deposition of the metal layer, there is performed annealing at a temperature equal to or exceeding the temperature of diffusion of the material of the barrier layer into the material of the layers adjacent thereto. The annealing is conducted for a period sufficient for a partial or a complete dissolution of the barrier layer.

Abstract: Apparatus for suspending particles in a fluidized bed within a coating chamber where the particles are coated with a substance contained in a reactant gas introduced into the chamber by means of a centrally arranged nozzle extending upwardly from the coating chamber floor. Levitating gas for suspending the particles in the fluidized bed is introduced into the chamber from around the centrally arranged nozzle and generally parallel with the chamber base to promote particle circulation through the fluidized bed and minimize deposition within the chamber in one species of the apparatus, the nozzle is supported upon a movable probe which forms a closure for an opening in the chamber base through which coated particles are unloaded.

Abstract: Coated nuclear fuel particles are produced by batchwise deposition of several pyrolytic carbon and/or silicon carbide layers on fuel particles wherein the first layer is a porous pyrolytic carbon layer and wherein the coated particles are subsequently sieved and/or sized. The process comprises fractionaling all of the coating batches according to the geometric density by the hydrostatic method of weighing by buoyancy after placing all batches in heavy liquids and selecting for further working up into fuel elements only the particle fraction which has a geometric density whose boundary value deviates from the average density by less than .+-.20%.

Abstract: A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

Abstract: Method for cryoinduced uniform deposition of cryogenic materials, such as deuterium-tritium (DT) mixtures, on the inner surface of hollow spherical members, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on the inner surface of the spherical member. Heating of the cryogenic material, located within a non-isothermal compact freezing cell, is accomplished by an electrical heat pulse, whereafter the material is quickly frozen forming a uniform layer on the inner surface of the spherical member. The method is not restricted to producing a frozen layer on only the inner surface of the innermost hollow member, but where multiple concentric hollow spheres are involved, such as in multiple shell targets for lasers, electron beams, etc.

Abstract: Fuel, fertile material or absorber material containing particles for high temperature fuel elements are coated in a fluidized bed by heating the particles and fluidizing through carrier gas preheated to the desired temperature. The coating gas, having a higher velocity than the carrier gas causing fluidizing, is blown into the fluidized particle bed from one or more nozzles from above counter to the flow of the carrier gas. The nozzles end above the fluidized layer.

Abstract: A method and multiple embodiments of apparatus for coating particles with a substance contained in a reactant gas, the particles being suspended in a fluidized bed within a coating chamber. In the method and each embodiment of the apparatus, the reactant gas is introduced into the coating chamber through an elongated nozzle closed at its upper end and including multiple lateral orifice openings for directing the reactant gas radially outwardly into the coating chamber. Means are preferably arranged about the base of the nozzle for introducing levitating gas radially and spirally outwardly into the chamber to further promote circulation of the particles and to accomplish more uniform coating.

Abstract: Carbon-coated microspheroids useful as fuels in nuclear reactors are produced with a low percentage of cracked coatings and are imparted increased strength and mechanical stability characteristics by annealing immediately after the carbon coating processes.

Abstract: Fuel, fertile material or absorber material containing particles for high temperature fuel elements are coated in a fluidized bed by heating the particles and fluidizing through carrier gas preheated to the desired temperature. The coating gas, having a higher velocity than the carrier gas causing fluidizing, is blown into the fluidized particle bed from one or more nozzles from above counter to the flow of the carrier gas. The nozzles end above the fluidized layer.

Abstract: A mixed oxide fuel of uranium dioxide and plutonium dioxide is in the form of mixed oxide particles with a diameter of 0.2 to 2 mm. A surface layer of the particles consists of UO.sub.2 with a plutonium content per unit of volume of at most 15 per cent of the average plutonium content per unit of volume of the particle. The particles are formed by extrusion through a concentric nozzle. A water emulsion of uranium dioxide is first pumped through the inner nozzle, after which a water emulsion of plutonium dioxide is pumped through the outer nozzle. Thereafter a water emulsion of uranium dioxide is pumped through the outer nozzle to surround the plutonium dioxide layer and then water emulsion of uranium dioxide is pumped through the first nozzle to complete the enclosure of the plutonium dioxide.

Abstract: Fuel particles in a fluidized bed are provided with a coating of pyrolytic carbon having substantially no property gradients by holding the speed of growth constant during the entire coating time and insuring the same speed of growth in all particles of the particle bed.

Abstract: A method for coating small diameter, low density particles with pyrolytic carbon is provided by fluidizing a bed of particles wherein at least 50 per cent of the particles have a density and diameter of at least two times the remainder of the particles and thereafter recovering the small diameter and coated particles.

Abstract: An improved process for producing porous spheroidal particles consisting of a metal carbide phase dispersed within a carbon matrix is described. According to the invention metal-loaded ion-exchange resin microspheres which have been carbonized are coated with a buffer carbon layer prior to conversion of the oxide to carbide in order to maintain porosity and avoid other adverse sintering effects.

Abstract: Fissionable fuels and/or fertile breeder materials for nuclear reactors crised of fissionable or potentially fissionable materials having evenly distributed throughout certain metal oxides, such as aluminum oxide and niobium oxide, exhibiting the capacity to retain products formed by nuclear fission as stable, nonvolatible compounds in the nuclear material. The fuel element is combined with an effective amount of oxide that is relatively nonvolatile, has a low neutron-capture cross-section and forms such stable, nonvolatile compounds with the solid products resulting from nuclear fission.

Abstract: A method of preparing waste fission products for storage comprising combining graphite powder and a carbonaceous binder into one component, mixing this component with alpha-silicon carbide, and sprinkling this mixture on to waste fission product particles as the particles are tumbled in the presence of a solvent to form a tacky "overcoating" around the particles.The "overcoated" particles are warm pressed to form a "green" body, then the temperature is raised to carbonize the binder. The body is then heated at an elevated temperature in contact with silicon so as to melt the silicon and impregnate the body, to form a matrix of beta-silicon carbide enclosing the waste fission product particles by reaction-sintering.

Abstract: A procedure for tagging sand with a radioisotope for use in the study of sediment transport involves the precipitation of a metal radioisotope in the form of an iodide directly on the sand, followed by heating the sand to a temperature sufficient to effect a phase transformation of the sand and a decomposition of the metal iodide, leaving the metal firmly attached to the sand.

Abstract: A method of producing a fuel particle is disclosed, which comprises forming hollow spheroids which have a mass number greater than 50, immersing said spheroids while under the presence of pressure and heat in a gaseous atmosphere containing an isotope, such as deuterium and tritium, so as to diffuse the gas into the spheroid and thereafter cooling said spheroids up to about 77.degree. Kelvin to about 4.degree. Kelvin.