An improved nuclear fuel that has enhanced oxidation resistance and a process for making it are disclosed. The fuel comprises a composite of U235 enriched U.sub.3Si.sub.2 particles and an amount less than 30% by weight of UO.sub.2 particles positioned along the surface of the U.sub.3Si.sub.2 particles. The composite may be compressed into a pellet form. The process comprises forming a layer of UO.sub.2 on the surface of U.sub.3Si.sub.2 particles, either by exposing U.sub.3Si.sub.2 particles to an atmosphere of up to 15% oxygen by volume dispersed in an inert gas for a period of time and at a temperature sufficient to form UO.sub.2 at the U.sub.3Si.sub.2 particle surface, or by mixing U.sub.3Si.sub.2 particles with an amount up to 30% by weight of UO.sub.2 particles.

A device for transferring a given powder or a mixture of given powders contained in a container including a side wall and at least one discharge opening, the container with axisymmetric shape having an axis of rotation being arranged in the transfer device such that the discharge opening thereof is located in a lower portion of the container, the transfer device including rotating the container about the axis thereof, on which the discharge opening is located and control for controlling the rotation such that the to rotation imposes on at least one portion of the side wall of the container, referred to as movable portion, a first moving phase wherein an acceleration no lower than a minimum acceleration is capable of causing the powder to slide relative to the movable portion.

The invention is related to nuclear technologies, in particular, to the technology of producing nuclear oxide fuel for fuel elements, this oxide fuel can be used for manufacturing palletized nuclear fuel from uranium dioxide to be consumed by NPPs. The essence of the invention: this method of producing palletized nuclear fuel from uranium dioxide involves preparation of uranium dioxide moulding powder with/without uranium oxide, at this point powdered uranium dioxide is used as a raw material for preparation of moulding powder. Powdered uranium dioxide should be in the following proportion: O/U=2.370.04, it is obtained using a renowned methodby air heating of powdered uranium dioxide (ceramic grade) with the following proportion O/U=2.012.15. The technical result of the invention is increased mechanical strength of sintered pellets and a larger grain size of sintered pellets. 3 appendices, 1 diagram, 2 figures

A fuel element has a ratio of area of fissionable nuclear fuel in a cross-section of the tubular fuel element perpendicular to the longitudinal axis to total area of the interior volume in the cross-section of the tubular fuel element that varies with position along the longitudinal axis. The ratio can vary with position along the longitudinal axis between a minimum of 0.30 and a maximum of 1.0. Increasing the ratio above and below the peak burn-up location associated with conventional systems reduces the peak burn-up and flattens and shifts the burn-up distribution, which is preferably Gaussian. The longitudinal variation can be implemented in fuel assemblies using fuel bodies, such as pellets, rods or annuli, or fuel in the form of metal sponge and meaningfully increases efficiency of fuel utilization.

The invention relates generally to uranium fuel in a nuclear reactor and, more particularly, the inclusion of a fuel additive component to the bulk fuel material. The fuel additive component is selected and provided in an amount such that it is effective to improve one or more properties of the bulk fuel material. The fuel additive component has a grain size that is less than the grain size of the bulk fuel material. The granular fuel additive component coats or covers the granular bulk fuel material.

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.

An improved, accident tolerant fuel for use in light water and lead fast reactors is described. The fuel includes a ceramic cladding, such as a multi-layered silicon carbide cladding, and fuel pellets formed from U.sup.15N and from 100 to 10000 ppm of a boron-containing integral fuel burnable absorber, such as UB.sub.2 or ZrB.sub.2.

Thorium-based fuel bundles according to one or more embodiments of the present invention are used in existing PHWR reactors (e.g., Indian 220 MWe PHWR, Indian 540 MWe PHWR, Indian 700 MWe PHWR, CANDU 300/600/900) in place of conventional uranium-based fuel bundles, with little or no modifications to the reactor. The fuel composition of such bundles is 60+ wt % thorium, with the balance of fuel provided by low-enriched uranium (LEU), which has been enriched to 13-19.95% 235U. According to various embodiments, the use of such thorium-based fuel bundles provides (1) 100% of the nominal power over the entire life cycle of the core, (2) high burnup, and (3) non-proliferative spent fuel bundles having a total isotopic uranium concentration of less than 12 wt %. Reprocessing of spent fuel bundles is also avoided.

The invention relates to the use of Dispersion Ceramic Micro-Encapsulated (DCM) nuclear fuel as a meltdown-proof, accident-tolerant fuel to replace uranium dioxide fuel in existing light water reactors (LWRs). The safety qualities of the DCM fuel are obtained by the combination of three strong barriers to fission product release (ceramic coatings around the fuel kernels), highly dense inert ceramic matrix around the coated fuel particles and metallic or ceramic cladding around the fuel pellets.

A fuel element has a ratio of area of fissionable nuclear fuel in a cross-section of the tubular fuel element perpendicular to the longitudinal axis to total area of the interior volume in the cross-section of the tubular fuel element that varies with position along the longitudinal axis. The ratio can vary with position along the longitudinal axis between a minimum of 0.30 and a maximum of 1.0. Increasing the ratio above and below the peak burn-up location associated with conventional systems reduces the peak burn-up and flattens and shifts the burn-up distribution, which is preferably Gaussian. The longitudinal variation can be implemented in fuel assemblies using fuel bodies, such as pellets, rods or annuli, or fuel in the form of metal sponge and meaningfully increases efficiency of fuel utilization.