A method for preparing a powder comprising an intimate mixture of U.sub.3O.sub.8 particles and PuO.sub.2 particles and which may further comprise particles of ThO.sub.2 or NpO.sub.2. The method comprises: preparing, via oxalic precipitations, an aqueous suspension S.sub.1 of particles of uranium(IV) oxalate and an aqueous suspension S.sub.2 of particles of plutonium(IV) oxalate; mixing the aqueous suspension S.sub.1 with the aqueous suspension S.sub.2 to obtain an aqueous suspension S.sub.1+2; separating the aqueous suspension S.sub.1+2 into an aqueous phase and a solid phase comprising the particles of uranium(IV) oxalate and the particles of plutonium(IV) oxalate; and calcining the solid phase to convert (1) the particles of uranium(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.

A method for preparing a powder comprising an intimate mixture of U.sub.3O.sub.8 particles and PuO.sub.2 particles and which may further comprise particles of ThO.sub.2 or NpO.sub.2. The method comprises: preparing, via oxalic precipitations, an aqueous suspension S.sub.1 of particles of uranium(IV) oxalate and an aqueous suspension S.sub.2 of particles of plutonium(IV) oxalate; mixing the aqueous suspension S.sub.1 with the aqueous suspension S.sub.2 to obtain an aqueous suspension S.sub.1+2; separating the aqueous suspension S.sub.1+2 into an aqueous phase and a solid phase comprising the particles of uranium(IV) oxalate and the particles of plutonium(IV) oxalate; and calcining the solid phase to convert (1) the particles of uranium(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.

A process for recovering uranium from components contaminated with uranium oxide includes providing a cleaning apparatus with a cleaning solution for dissolving the uranium oxide of the components, carrying out a cleaning process by introducing a batch of components into the cleaning apparatus, and carrying out a measurement for determining the uranium content of the components. The cleaning and the measuring are repeated if a limit value for the uranium content is exceeded. The components are discharged from the process if the uranium content falls below a limit value. The cleaning is carried out on a plurality of successive batches of components until a control measurement indicates an unsatisfactory cleaning action of the cleaning solution. The uranium oxide dissolved in the cleaning solution is recovered after indication of the unsatisfactory cleaning action.

The present invention relates to single crystalline RbUO.sub.3, hydrothermal growth processes of making such single crystals and methods of using such single crystals. In particular, Applicants disclose single crystalline RbUO.sub.3 single crystalline RbUO.sub.3 in the Pm-3m space group. Unlike other powdered RbUO.sub.3, Applicants' single crystalline RbUO.sub.3 has a sufficient crystal size to be characterized and used in the fields of neutron detection, radiation-hardened electronics, nuclear forensics, nuclear engineering photovoltaics, lasers, light-emitting diodes, photoelectrolysis and magnetic applications.

The present invention relates to single crystalline RbUO.sub.3, hydrothermal growth processes of making such single crystals and methods of using such single crystals. In particular, Applicants disclose single crystalline RbUO.sub.3 single crystalline RbUO.sub.3 in the Pm-3m space group. Unlike other powdered RbUO.sub.3, Applicants' single crystalline RbUO.sub.3 has a sufficient crystal size to be characterized and used in the fields of neutron detection, radiation-hardened electronics, nuclear forensics, nuclear engineering photovoltaics, lasers, light-emitting diodes, photoelectrolysis and magnetic applications.

A thermochemical method for storing and releasing thermal energy by means of a compound in solid form of formula AO.sub.xB.sub.y.zH.sub.2O, in which: A is an element selected from uranium (U) and thorium (Th); O is the element oxygen; B is an anion or an oxoanion; x is a number comprised between 0 and 4; y is a number comprised between 0 and 2; z is a number greater than 0 and less than 10; it being understood that at least one of x and y is different from 0 and that the compound of formula Th(SO.sub.4).sub.2.xH.sub.2O is excluded.

A method for purifying uranium includes forming primary uranyl peroxide precipitates (UO.sub.2O.sub.2.4H.sub.2O). Forming the primary uranyl peroxide precipitates includes obtaining impure uranium dissolved in an acidic solution, evaporating the acidic solution to increase uranium concentration and to form a concentrated solution, mixing a hydrogen peroxide (H.sub.2O.sub.2) solution with the concentrated solution in a first container, and forming uranyl peroxide precipitates in the first container. The method includes collecting the uranyl peroxide precipitates and washing and drying the uranyl peroxide precipitates. The method also includes converting the washed and dried uranyl peroxide precipitates into triuranium octoxide (U.sub.3O.sub.8).

The present invention provides a process for the production of a uranium trioxide yellowcake from a uranium peroxide precipitate, the peroxide precipitate being in the form of a low solids content, uranium rich feed slurry, the process including the stages of: a. thickening the feed slurry to produce a thickener underflow with a solids content in the range of 15 to 50% w/w and a thickener overflow; b. dewatering the thickener underflow to produce a solids cake with a solids content of at least 50% w/w and a dewater overflow; and c. calcining the solids cake at a temperature in the range of 450° C. to 480° C. to produce a calcined uranium trioxide yellowcake.

The present invention provides a process for the production of a uranium trioxide yellowcake from a uranium peroxide precipitate, the peroxide precipitate being in the form of a low solids content, uranium rich feed slurry, the process including the stages of: a. thickening the feed slurry to produce a thickener underflow with a solids content in the range of 15 to 50% w/w and a thickener overflow; b. dewatering the thickener underflow to produce a solids cake with a solids content of at least 50% w/w and a dewater overflow; and c. calcining the solids cake at a temperature in the range of 450° C. to 480° C. to produce a calcined uranium trioxide yellowcake.

The present invention relates to single crystalline NaUO.sub.3, hydrothermal growth processes of making such single crystals and methods of using such single crystals. In particular, Applicants disclose single crystalline NaUO.sub.3 in the R32 space group. Unlike other powdered NaUO.sub.3, Applicants' single crystalline NaUO.sub.3 has a sufficient crystal size to be characterized and used in the fields of laser light, infrared countermeasures, nuclear fuel material, nuclear forensics and magnetic applications.