81results about "Uranium oxides/hydroxides" patented technology

A method of stabilizing nuclear material is disclosed. Oxides or halides of actinides and / or transuranics (TRUs) and / or hydrocarbons and / or acids contaminated with actinides and / or TRUs are treated by adjusting the pH of the nuclear material to not less than about 5 and adding sufficient MgO to convert fluorides present to MgF2; alumina is added in an amount sufficient to absorb substantially all hydrocarbon liquid present, after which a binder including MgO and KH2PO4 is added to the treated nuclear material to form a slurry. Additional MgO may be added. A crystalline radioactive material is also disclosed having a binder of the reaction product of calcined MgO and KH2PO4 and a radioactive material of the oxides and / or halides of actinides and / or transuranics (TRUs). Acids contaminated with actinides and / or TRUs, and / or actinides and / or TRUs with or without oils and / or greases may be encapsulated and stabilized by the binder.

The object of the present invention is to provide the following devices: a dripping nozzle device that forms substantially spherical ADU particles, a dripping stock solution recovery device that prepares a homogeneous dripping stock solution, a dripping stock solution supply device that can drop liquid droplets of a uniform volume, and even liquid droplets Droplet surface solidification device that does not deform when it collides with the surface of ammonia solution when dropped, ammonia solution circulation device that can fully turn uranyl nitrate into ADU from the center of the droplet, and ADU with good sphericity The ADU particle manufacturing device for particles, the dripping nozzle device has an exciter that vibrates multiple nozzles at the same time, the dripping stock solution recovery device recovers the bottom fine stock solution in the nozzle and mixes it into the dripping stock solution, and the dripping stock solution supply device has a mechanism for falling The light irradiation mechanism that irradiates the droplet of the original solution with light, the droplet surface curing device sprays ammonia gas toward the drop path of the droplet of the original solution dripped from the nozzle, and the ammonia solution circulation device can make the droplets in the ammonia solution storage tank The ammonium diuranate particle manufacturing device uses the above-mentioned device for ascending flow in the ammonia solution in the interior.

A powder of a metal oxide except for alpha -alumina, which is constituted of at least six-sided polyhedral particles and has a number-average particle diameter of 0.1-300 mu m and a particle size distribution of 10 or less in terms of D90 / D10 (wherein D10 and D90 represent the particle diameters corresponding to the cumulative amount of, respectively, 10 % and 90 % as determined from the finer particle side in the cumulative size distribution curve for the particles constituting the powder); and a powder of rutile titanium oxide constituted of at least eight-sided polyhedral particles. These powders are reduced in the content of aggregated particles and have a narrow particle size distribution and uniform particle shapes.

A process for the extraction of uranium compounds from wet-process phosphoric acid includes lowering the iron concentration of the wet-process phosphoric acid and reducing the valency of any remaining ferric iron in the wet-process phosphoric acid to ferrous iron, and then extracting uranium compounds from the wet-process phosphoric acid. The process can include separating a side stream from a feed stream of wet-process phosphoric acid, wherein the side stream has a greater concentration of the uranium compounds than the feed stream by filtration. Extracting uranium compounds from the wet-process phosphoric acid can be by ion exchange process or by solvent extraction.

The invention discloses a method for preparing a monodisperse micron-sized uranium oxide particle by using a sol-spray thermal decomposition method. The method comprises the following steps of: forming a monodisperse aerosol by a uranyl nitrate solution by using a vibrating orifice aerosol generator; drying and carrying out static removal to form a uranyl nitrate solid particle; carrying out high-temperature thermal decomposition to form a monodisperse uranium oxide particle; and collecting after cooling, wherein carrier gas is preheated at the back end of a neutralizer to a temperature of 70-80 DEG C or so, the flow of the carrier gas is 35-45 L / min, and the high-temperature thermal decomposition is carried out by the direct heating of a muffle furnace. The technical scheme of the invention is simpler and more convenient and ensures the safety in the operation process.

A process for reprocessing a spent nuclear fuel and for preparing a mixed uranium-plutonium oxide. The process: a) separates the uranium and plutonium from fission products, americium, and curium that are present in an aqueous nitric solution resulting from dissolution of the fuel in nitric acid, the separating including at least one operation of coextracting the uranium and plutonium from the solution by a solvent phase; b) partitions the coextracted uranium and plutonium to a first aqueous phase containing plutonium and uranium, and a second aqueous phase containing uranium but no plutonium; c) purifies the plutonium and uranium that are present in the first aqueous phase; and d) coconverts the plutonium and uranium to a mixed uranium / plutonium oxide.

This invention provides a dripping nozzle device to produce ADU particles with good sphericity, a device for recovering a feedstock liquid to prepare a uniform feedstock liquid, a device for supplying a feedstock liquid to form drops with a uniform volume, a device for solidifying the surfaces of drops so that the drops will not deform easily when they fall onto and hit the surface of an aqueous ammonia solution, a device for circulating an aqueous ammonia solution so that the uranyl nitrate in the drops can be changed to ammonium diuranate completely, to such an extent that uranyl nitrate in the center of each drop is changed to ammonium diuranate, and an apparatus for producing ammonium diuranate particles with good sphericity. The dripping nozzle device is provided with a single vibrator to vibrate nozzles simultaneously. The device for recovering a feedstock liquid recovers the feedstock liquid remaining in the nozzles and mixes it with a fresh feedstock liquid. The device for supplying a feedstock liquid is provided with a light irradiator for irradiating falling drops with light. The device for solidifying the surfaces of drops sprays ammonia gas over each of the paths along which the drops dripping from the nozzles fall. The device for circulating an aqueous ammonia solution enables drops to flow upward in the aqueous ammonia solution in the aqueous ammonia solution reservoir. The apparatus for producing ammonium diuranate utilizes these devices.

A method for making a metal-titania pulp and photocatalyst is provided, including firstly acidically hydrolyzing a titanium alkoxide solution in presence of an alcohol solvent to get a colloidal solution; then, adding at least one metal salt solution into the colloidal solution to produce a nano-porous metal / titania photocatalyst under appropriate conditions by appropriate reaction. The nano-porous metal / titania photocatalyst thus prepared has excellent optical activity and is applicable in research of water decomposition with light to improve production efficiency of hydrogen energy. In addition, the photocatalyst is further processed in the form of powder or film to facilitate industrial application in wastewater treatment.

A method for reprocessing spent nuclear fuel from a light water reactor includes the step of reacting spent nuclear fuel in a voloxidation vessel with an oxidizing gas having nitrogen dioxide and oxygen for a period sufficient to generate a solid oxidation product of the spent nuclear fuel. The reacting step includes the step of reacting, in a first zone of the voloxidation vessel, spent nuclear fuel with the oxidizing gas at a temperature ranging from 200-450° C. to form an oxidized reaction product, and regenerating nitrogen dioxide, in a second zone of the voloxidation vessel, by reacting oxidizing gas comprising nitrogen monoxide and oxygen at a temperature ranging from 0-80° C. The first zone and the second zone can be separate. A voloxidation system is also disclosed.

The invention relates to a method for preparing a powder comprising an intimate mixture of U3O8 particles and PuO2 particles and which may further comprise particles of ThO2 or NpO2. The method comprises: a) preparing, by oxalic precipitations, an aqueous suspension Si of particles of uranium(IV) oxalate and an aqueous suspension S2 of particles of plutonium(IV) oxalate; b) mixing the aqueous suspension Si with the aqueous suspension S2 to obtain an aqueous suspension S1+2 comprising particles of uranium(IV) oxalate and particles of plutonium(IV) oxalate; c) separating the aqueous suspension S1+2 into an aqueous phase and a solid phase comprising the particles of uranium(IV) oxalate and the particles of plutonium(IV) oxalate; and d) calcining the solid phase to convert (1) the particles ofuranium(IV) oxalate to particles of triuranium octoxide and (2) the particles of plutonium(IV) oxalate to particles of plutonium(IV) dioxide, whereby the powder is obtained; and is characterized in that steps b) and c) are performed simultaneously or successively. The invention further relates to the fabrication of nuclear fuels of MOX type, e.g. for LWR or FNR reactors.