Abstract: A method is disclosed for making a fuel pellet for a nuclear reactor. A mixture is prepared of PuO.sub.2 and UO.sub.2 powders, where the mixture contains at least about 30% PuO.sub.2, and where at least about 12% of the Pu is the Pu.sup.240 isotope. To this mixture is added about 0.3 to about 5% of a binder having a melting point of at least about 250.degree. F. The mixture is pressed to form a slug and the slug is granulated. Up to about 4.7% of a lubricant having a melting point of at least about 330.degree. F. is added to the granulated slug. Both the binder and the lubricant are selected from a group consisting of polyvinyl carboxylate, polyvinyl alcohol, naturally occurring high molecular weight cellulosic polymers, chemically modified high molecular weight cellulosic polymers, and mixtures thereof. The mixture is pressed to form a pellet and the pellet is sintered.

Abstract: The invention relates to a process for the treatment of a metal oxide powder, particularly a UO.sub.2 or PuO.sub.2 powder, with a view to its fritting.This process consists of oxidizing the powder, so as to form on its surface a hydrated oxide layer of the same metal. When the oxide is UO.sub.2 or PuO.sub.2 and mixtures thereof, as well as those prepared with ThO.sub.2, the treated powder can be used for producing nuclear fuel pellets by cold compression, followed by fritting.

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: There is described a process for the production of ceramic fuel pellets which contain fission and/or fertile material in oxidized form, by heating porous green fuel pellets in a reducing atmosphere to a temperature below 2500.degree. C., molding in a die, ejecting from the die and cooling the finished pellets. Thereby the heating and cooling is carried out stepwise whereby the heating and cooling speed below 1200.degree. C. is less than 30.degree. C./second and above 1200.degree. C. is greater than 30.degree. C./second.

Abstract: Method for dissolving hard-to-dissolve thorium and/or plutonium oxides, especially dioxides such as ThO.sub.2, PuO.sub.2 or (U/Pu)O.sub.2 mixed oxides by heating the oxides in a hermetically sealed vessel in fluoride-free nitric acid. The use of a gas atmosphere containing oxygen in the sealed vessel is advantageous.

Abstract: A process for manufacturing uranium dioxide powder which comprises forming fine uranium dioxide powder having a high sinterability and coarse uranium dioxide powder having a low sinterability continuously in one process by changing periodically the precipitation condition of the ammonium diuranate under the same condition of calcining and reducing of the ammonium diuranate. The thus obtained mixture of these uranium dioxide powders is suitable for uranium dioxide pellet which is a fuel of nuclear power reactor.

Abstract: A nuclear fuel conversion system comprises a unit for heating and denitrifying a nitric acid solution of uranyl nitrate, plutonium nitrate, or mixture thereof, a unit for grinding denitrified products, a unit connected to the grinding unit through a first conveying unit for roasting and reducing ground products, a unit connected to the roast-reduction unit through a second conveying unit for further grinding and then sieving the roasted and reduced products, and a unit for disposing of waste gases and waste liquor. The denitrification unit includes a microwave generator for heating and denitrifying the nitric acid solution and for cooling the denitrified product, and the first and second conveying units comprise pneumatic carrier means each of which consists of a suction nozzle, cyclone connected to the nozzle through a pipe, and a blower for creating a reduced pressure condition in the pipe.

Abstract: Disclosed is a method of making a pellet from a powder by placing the powder in a heat-shrinkable container, sealing the container and isostatically pressing the container at a temperature which causes it to shrink, followed by decomposition of the container and sintering of the powder. In preparing nuclear fuel pellets, a free-flowing fissile powder is mixed with a free-flowing fertile powder and the mixture is placed in the heat-shrinkable container. The container is sealed, heated and isostatically pressed, then decomposed and the powder is sintered.

Abstract: A method for co-conversion of aqueous solutions of one or more heavy metal nitrates wherein thermal decomposition within a temperature range of about 300.degree. to 800.degree. C. is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

Abstract: The grain size of particulate uranium oxides is increased and adjusted by the application thereto of hydrogen peroxide. The procedure is useful in the manufacture of nuclear reactor fuel from powdered fissionable materials.

Abstract: Method for direct coprocessing of nuclear fuels derived from a product stream of a fuels reprocessing facility containing uranium, plutonium, and fission product values comprising nitrate stabilization of said stream vacuum concentration to remove water and nitrates, neutralization to form an acid deficient feed solution for the internal gelation mode of sol-gel technology, green spherule formation, recovery and treatment for loading into a fuel element by vibra packed or pellet formation technologies.

Abstract: An improved method for preparing nuclear fuel pellets and recycling uranium dioxide utilizing microwave radiation wherein microwave induction furnaces replace conventional refractory-type sintering and shaker-air furnaces.

Abstract: A nuclear fuel material green body of density from about 30 to 70% of theoretical density having tensile strength and plasticity adequate to maintain the integrity of the body during processing leading to ultimate sintered condition is produced by adding one or more amines to a particulate mass of the nuclear fuel containing about five percent of ammonium uranyl carbonate under conditions resulting in reaction of the amine with the ammonium uranyl carbonate, liberation of ammonia and formation of a water-soluble uranyl compound more effective as a binder than the ammonium uranyl carbonate.

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 compacting die wherein the improvement comprises providing a screen in the die cavity, the screen being positioned parallel to the side walls of said die and dividing the die cavity into center and annular compartments. In addition, the use of this die in a method for producing an annular clad ceramic fuel material is disclosed.

Abstract: A method for the heat treatment of a radioactive substance by microwave power comprising preparing a nitrate solution of uranium, thorium, plutonium or a mixture thereof, and applying to the nitrate solution microwave energy sufficient to directly convert the nitrate solution into an oxide powder of uranium, thorium, plutonium or a mixture thereof, respectively. Such oxide powder is suitable for the manufacture of nuclear fuel pellets.

Abstract: Manufacture of oxidic nuclear fuel bodies with oxygen-to-metal ratio of 2.0.+-.0.02 at relatively low sintering temperature in range of 1000.degree.-1400.degree. C. Nuclear fuel powder with an arbitrary oxygen-to-metal ratio is mixed with a grain-growth promoting additive (U.sub.3 O.sub.8) and pressed into blanks. The blanks are subjected to a two-stage operation in a furnace at 1000.degree.-1400.degree. C. - an oxidative-sintering stage in a carbon dioxide atmosphere and a reducing stage in a hydrogen containing atmosphere.

Abstract: In a process for reducing the oxygen content of metal oxide material, particularly a nuclear fuel material, the metal oxide material is contained in a plurality of carbon crucibles which are moved through a heated zone in end-to-end contact counter current to a stream of hydrogen-containing gas.