Methods for forming particulates that are highly consistent with regard to shape, size, and content are described. Particulates are suitable for use as reference materials. Methods can incorporate actinides and/or lanthanides, e.g., uranium, and can be used for forming certified reference materials for use in the nuclear industry. Methods include formation of an aerosol from an oxalate salt solution, in-line diagnostics, and collection of particles of the aerosol either in a liquid impinger or on a solid surface.

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.

The invention relates to the field of nuclear technologies, in particular to an oxide-based uranium-plutonium nuclear fuel for an atomic power station with thermal neutron reactors. The technical result of the invention is the development of a REMIX-type fuel composition formulation making it possible, in the nuclear fuel cycle, to involve fissile nuclear materials regenerated from spent nuclear fuel with the simultaneous use of enriched natural uranium, and also moreover providing a solution to the problems of separately using previously isolated plutonium (including weapons-grade plutonium), of reducing the quantity of spent nuclear fuel by recycling fissile materials from spent nuclear fuel during the lifespan of a nuclear reactor (up to 5 recyclings), of economizing on natural uranium for manufacturing fuel and, as a result, of making the nuclear fuel cycle self-sustainable. The invention makes it possible to use REMIX fuel for solving an entire range of problems which a closed nuclear fuel cycle may face, taking into account the number of reactors, availability of natural uranium and the amount of stored spent nuclear fuel.

A nuclear fuel element includes a core comprising a fissile element and an additional element. A protective structure surrounds the core and comprises at least a first material surrounding the nuclear fuel. The first material comprises the fissile element and the additional element and comprises a greater than stoichiometric amount of the additional element. An outer portion of the nuclear fuel element comprises a metal. Related nuclear fuel elements, and related methods are also disclosed.

Disclosed are a nuclear fuel pellet having enhanced thermal conductivity and a method of manufacturing the same, the method including (a) a step of manufacturing a mixture including a nuclear fuel oxide powder and a thermally conductive plate-shaped metal powder; and (b) a step of molding and then heat-treating the thermally conductive plate-shaped metal powder to have an orientation in a horizontal direction in the mixture, thereby forming a pellet.

A method for manufacturing a nuclear fuel compact is provided. The method includes forming an additive structure, consolidating a fuel matrix around the additive structure, and thermally processing the fuel matrix to form a fuel compact in which the additive structure is encapsulated therein. The additive structure optionally includes a vertical segment and a plurality of arm segments that extend generally radially from the vertical segment for conducting heat outwardly toward an exterior of the fuel compact. In addition to improving heat transfer, the additive structure may function as burnable absorbers, and may provide fission product trapping.

A method for detecting the thicknesses of coating layers of nuclear fuel particles, comprising: collecting a surface image of a sample to be tested under a first amplification factor (S310); determining a testable particle in the surface image (S320); collecting a cross section image of the testable particle under a second amplification factor, wherein the second amplification factor is greater than the first amplification factor (S330); and determining the center of the testable particle in the cross section image and profile lines of all coating layers, and determining the thickness of each coating layer according to the center and the profile lines of each coating layer (S340). Also provided is a device for detecting the thicknesses of coating layers of the nuclear fuel particles.

To provide is a fuel assembly capable of easily adjusting average MA enrichment in an inner blanket region. An inner core fuel assembly 7 loaded in an inner core region 2 of a core of a fast reactor includes a plurality of fuel rods 10 and a plurality of fuel rods 19. Each of the fuel rods 10 includes a lower core fuel region 12, an inner blanket region 11, and an upper core fuel region 13. A U—Pu—Zr metal fuel is disposed in the lower core fuel region 12 and the upper core fuel region 13, and a U—Zr metal fuel is disposed in the inner blanket region 11. Each of the fuel rods 19 includes a lower core fuel region 12, an inner blanket region 20, and an upper core fuel region 13. A U—Pu—Zr metal fuel is disposed in the lower core fuel region 12 and the upper core fuel region 13 of the fuel rod 19, and a MA-Zr metal fuel is disposed in the inner blanket region 20. By adjusting the number of the fuel rods 10 and the number of the fuel rods 19, MA enrichment in the inner blanket region 9 of the fuel assembly 7 can be easily adjusted.

Methods for forming particulates that are highly consistent with regard to shape, size, and content are described. Particulates are suitable for use as reference materials. Methods can incorporate actinides and/or lanthanides, e.g., uranium, and can be used for forming certified reference materials for use in the nuclear industry. Methods include formation of an aerosol from an oxalate salt solution, in-line diagnostics, and collection of particles of the aerosol either in a liquid impinger or on a solid surface.

Disclosed herein is a method for manufacturing oxide fuel pellets. The method for manufacturing the oxide fuel pellets includes (step 1) preparing nuclear fuel powder containing uranium dioxide (UO2+x, x=0 to 0.20), (step 2) compacting the nuclear fuel powder prepared in step 1 to manufacture green pellets, sintering the green pellets manufactured in step 2 at a temperature of about 1,200° C. to about 1,400° C. by using an atmosphere gas, and reducing the green pellets sintered in step 3 at a temperature of about 800° C. to about 1,000° C. by using a reducing atmosphere gas. The method for manufacturing the oxide fuel pellets according to the present invention performs the sintering at a low temperature of about 1,200° C. to 1,400° C. to manufacture economical and safe oxide fuel pellets that are adequate for the nuclear fuel specification.