Method and device for the preparation of monophasic powders of actinide salts which are precursors in the production of fuel pellets. In one aspect, a compact and simple device is provided to obtain dry monophasic powders of actinide salts in one stage, while increasing the productivity, chemical and nuclear safety of the process. In a second aspect, the method comprises feeding of nitric actinides-containing solution and formic acid to a cylindrical healed reactor, grinding the resulting powder, and disc hanging the powder. The nitric actinides-containing solution and formic acid are continuously metered to the upper zone of the reactor so that the reactive chemicals are mixed in a thin film on the heat-exchange surface, where the reaction mixture is continuously stirred by rotor blades. Also occurring are the processes of denitration, formation of the relevant compounds, their drying and grinding and collecting dry salts of actinides in a hopper by gravity.

The present disclosure relates to a pellet containing an oxide additive to improve a nuclear-fission-gas-adsorption ability of a uranium-dioxide pellet used as nuclear fuel and increase the grain size thereof, and to a method of manufacturing the same. A La.sub.2O.sub.3—Al.sub.2O.sub.3—SiO.sub.2 sintering additive is added to uranium dioxide so that mass movement is accelerated due to the liquid phase generated during sintering of the uranium-dioxide pellet, which promotes the growth of grains thereof. Further, since less volatilization occurs during sintering due to the low vapor pressure of the liquid phase, efficient additive performance is exhibited, so the liquid phase surrounding the grain boundary effectively adsorbs cesium, which is a nuclear fission gas.

A channel type heterogeneous reactor core for a heavy water reactor for burnup of thorium based fuel is provided. The heterogeneous reactor core comprises at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel; and at least one blanket fuel channel region comprising blanket fuel channels for receiving blanket fuel bundles of thorium based fuel; wherein the seed fuel bundles have a higher percentage content of fissile fuel than the blanket fuel bundles. The seed fuel channel region and the blanket fuel channel region may be set out in a checkerboard pattern or an annular pattern within the heterogeneous reactor core. Fuel bundles for the core are also provided.

A channel type heterogeneous reactor core for a heavy water reactor for burnup of thorium based fuel is provided. The heterogeneous reactor core comprises at least one seed fuel channel region comprising seed fuel channels for receiving seed fuel bundles of thorium based fuel; and at least one blanket fuel channel region comprising blanket fuel channels for receiving blanket fuel bundles of thorium based fuel; wherein the seed fuel bundles have a higher percentage content of fissile fuel than the blanket fuel bundles. The seed fuel channel region and the blanket fuel channel region may be set out in a checkerboard pattern or an annular pattern within the heterogeneous reactor core. Fuel bundles for the core are also provided.

A methodology is disclosed for compaction of a ceramic matrix of certain nuclear fuels incorporating neutron poisons, whereby those poisons aid in reactor control while aiding in fuel fabrication. Neutronic poisons are rare-earth oxides that readily form eutectics suppressing fuel fabrication temperature, of particular importance to the fully ceramic microencapsulated fuel form and fuel forms with volatile species.

The fuel of NPPs on thermal neutrons. A fuel composition is proposed, which includes a mixture of regenerated plutonium and enriched uranium in the form of oxides, in which the enriched natural uranium is used as enriched uranium as well as regenerated plutonium, with a ratio of components, determined by the energy potential, equal to the potential of freshly prepared NPP fuel from enriched natural uranium, which provides the loading of the reactor core up to 100%. Possible options of the specified components are claimed, including unlimited cycling of the secondary regenerated plutonium and uranium. The use of the proposed composition makes it possible to use of the uranium and plutonium energy potential at maximum level, including accumulated SNF, and sharply reduce the volume of warehouses, up to their decommissioning, as well as significantly simplify the logistics and technology of manufacturing nuclear fuel from recycled materials.

Provided is a nuclear-fuel sintered pellet based on oxide in which a plate-type fine precipitate material in a base of a sintered pellet of uranium dioxide, used as nuclear fuel in nuclear power plants, is uniformly dispersed in a matrix of uranium dioxide fuel thereof so as to form a donut-shaped precipitate cluster, and to a method of manufacturing the same. The plate-type fine precipitate material is uniformly precipitated in a tissue thereof or forms a donut-shaped precipitate cluster having a two-dimensional structure through dispersion to improve thermal and physical performance of the nuclear-fuel sintered pellet of uranium dioxide, whereby the creep deformation rate and thermal conductivity of the sintered pellet are improved. The nuclear-fuel sintered pellet based on oxide can reduce the Pellet-Clad Interaction (PCI) failure and the core temperature of nuclear fuel when an accident occurs, thereby significantly improving the safety of a nuclear reactor.

A nuclear fuel element comprises a core comprising a fissile element and an additional element, a first material surrounding the nuclear fuel, the first material comprising the fissile element and the additional element, the first material comprising a greater than stoichiometric amount of the additional element, and a metal around an outer portion of the nuclear fuel element. Related nuclear fuel elements, and related methods are disclosed.

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 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.