Abstract: A composition filled with actinide powder, comprising an organic matrix and an actinide powder or a mixture of actinide powders, comprises at least: a plasticizer comprising an alkane whose longest radical chain comprises at least a few tens of carbon atoms and is in a volume content of between 20% and 70% of the total volume of the organic compounds alone; a binder comprising at least one aromatic polymer and/or polymethyl methacrylate and which is in a volume content of between 20% and 50% of the total volume of the organic compounds alone; a dispersant comprising a carboxylic acid or salts thereof, the volume content of which is less than 10% of the total volume of the organic compounds alone; said actinide powder or said mixture of actinide powders represent between 40% and 65% of the volume of the filled matrix.

Abstract: Microstructured nuclear fuel adapted for nuclear power system use includes fissile material structures of micrometer-scale dimension dispersed in a matrix material. In one method of production, fissile material particles are processed in a chemical vapor deposition (CVD) fluidized-bed reactor including a gas inlet for providing controlled gas flow into a particle coating chamber, a lower bed hot zone region to contain powder, and an upper bed region to enable powder expansion. At least one pneumatic or electric vibrator is operationally coupled to the particle coating chamber for causing vibration of the particle coater to promote uniform powder coating within the particle coater during fuel processing. An exhaust associated with the particle coating chamber and can provide a port for placement and removal of particles and powder. During use of the fuel in a nuclear power reactor, fission products escape from the fissile material structures and come to rest in the matrix material.

Abstract: A process for the treatment of radioactive graphite which includes the following steps: (i) reacting the radioactive graphite at a temperature in the range of from 250° C. to 900° C. with superheated steam or gases containing water vapor to form hydrogen and carbon monoxide; (ii) reacting the hydrogen and carbon monoxide from step (i) to form water and carbon dioxide; and (iii) reacting the carbon dioxide of step (ii) with metal oxides to for carbonate salts. The process enables radioactive graphite, such as graphite moderator, to be treated either in-situ or externally of a decommissioned nuclear reactor.

Abstract: A method of preparing active, sinterable, finely-divided plutonium oxide (PuO.sub.2) powder from plutonium metal is disclosed. The process yields plutonium fissile material which can be easily blended to form a uniformly homogeneous powder for the fabrication of high-quality light water reactor ceramic fuel pellets. Such homogeneous fuels are required to prevent hot spots from developing in a reactor using the fuel.

Abstract: A method for producing UO.sub.2 or (U/Pu)O.sub.2 powder includes obtaining ammonium uranyl carbonate or ammonium uranyl plutonyl carbonate by treating a starting oxide selected from the group consisting of uranium oxide, plutonium oxide and uranium plutonium mixed oxide, with at least one solution selected from the group consisting of aqueous ammonium carbonate solution and aqueous ammonium hydrogen carbonate solution. The ammonium uranyl carbonate or ammonium uranyl plutonyl carbonate is then heated and in particular calcined.

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 treating process for the separation of coated nuclear fuel particles from a graphitic matrix in which the nuclear fuel particles are embedded, which is employed in an installation for the conditioning of graphitic fuel elements of high-temperature nuclear reactors. The graphite which encompasses the nuclear fuel particles is conducted away through the action of a brush which isolates the nuclear fuel particles together with their coatings or the nuclear particles themselves, and wherein the nuclear fuel particles which are contained in the brushed product are then separated from the comminuted graphite. The nuclear fuel particles are worked out of the graphitic matrix through the action of the bristles of the brush which conduct the graphite away, but in which the coated nuclear fuel particles when they are contained within hard coatings or the nuclear fuel particles themselves, remain preserved.

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: 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: Method for the manufacture of oxidic nuclear fuel bodies by a heat treatment of blanks obtained from UO.sub.2 starting power or a mixture of UO.sub.2 and PuO.sub.2 starting powder at a treatment temperature in the range of 1000.degree. C. to 1400.degree. initially in a gas atmosphere with oxidizing action and subsequently in a gas atmosphere with reducing action. The oxygen potential of the gas atmosphere with oxidizing action is kept in a range in which a crystallographically demonstrable U.sub.4 O.sub.9 or (U, Pu).sub.4 O.sub.9 crystal phase is generated in the blanks during the heating to the treatment temperature in this gas atmosphere with oxidizing action.

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: An improved method for compression molding typically brittle, particulate ceramic materials comprising uranium dioxide in the manufacture of nuclear fuel products.

Abstract: Removal of the graphite structure from the nuclear fuel material of fuel elements of gas-cooled high-temperature reactors is performed by heat-treatment of the fuel elements in oxygen-containing gas at temperatures below 700.degree. C. until the carbon or graphite structure is loosened up and converted into a mechanically removable material. During heat-treatment, mechanical forces are preferably applied for continually removing the outer layers that are most heavily attacked and transport of the dust into cooler temperature zones. For this purpose, the fuel elements are agitated during heat-treatment, as by an oscillating sieve or by brushes. Pre-impregnation with a material catalyzing the combustion is useful if it is important to have the heat-treatment temperature as low as possible.

Abstract: A nuclear fuel material green body of density from about 30 to 70% of theoretical density having tensile strenght and plasticity adequate to maintain the integrity of the body during processing leading to ultimate sintered condition is produced by adding an amine carbonate or carbamate or mixture thereof to a particulate mass of the nuclear fuel material under conditions resulting in reaction with the amine compound to form a water-soluble compound effective as a binder for the particulate material.

Abstract: Nuclear fuel microspheres are made by sintering microspheres containing uranium dioxide and uncombined carbon in a 1 mole percent carbon monoxide/99 mole percent argon atmosphere at 1550.degree. C. and then sintering the microspheres in a 3 mole percent carbon monoxide/97 mole percent argon atmosphere at the same temperature.