A device for granulating powders by cryogenic atomisation, characterised in that it comprises: a device for mixing powders by cryogenic fluid, comprising at least one chamber for mixing powders, comprising a cryogenic fluid; and a device for atomising a suspension of powders mixed by the device for mixing powders in order to allow a granulation of the powders, comprising a way of fractionating the suspension of powders making it possible to adjust the size of the droplets of powders to be atomised, and a method for adjusting the moisture of the mixed powders and/or the moisture of the atomisation atmosphere.

A method of making a nuclear fuel pellet for a nuclear power reactor. The method includes providing a nuclear fuel material in powder form, providing an additive, forming a so-called green pellet, wherein said additive is added either to said nuclear fuel material in powder form or to the green pellet, sintering the green pellet, wherein said additive is such that it causes larger grains in the nuclear fuel pellet, and wherein said additive is made of or includes a substance which causes the larger grains and which substantially leaves at least an outer portion of the pellet before and/or during the sintering step.

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.

Fuel pellets can include a fission material powder, a protective layer coated on the fission material powder, and an oxidation diffusion barrier coated on the protective layer, with the protective layer and oxidation diffusion barrier being formed through ALD to achieve infiltration of the coatings within the fuel pellets.

This invention relates to a composition and method for manufacturing a large-grained uranium oxide nuclear fuel pellet containing an additive. The nuclear fuel pellet is configured such that a uranium oxide powder and an additive powder composed of an Mg compound and a Si compound or Ca compound and a Al compound are mixed together, thus increasing a grain size to thus suppress the release of fission products, thereby increasing the stability of nuclear fuel, preventing cladding tubes from breaking, and contributing to the stable operation of nuclear power plants, ultimately increasing the overall stability of nuclear power plants including nuclear fuel.

A nuclear fuel pellet for a nuclear reactor is disclosed. The pellet comprises a metallic matrix and ceramic fuel particles of a fissile material dispersed in the metallic matrix. The metallic matrix is an alloy consisting of the principle elements U, Zr, Nb and Ti, and of possible rest elements. The concentration of each of the principle elements in the metallic matrix is at the most 50 molar-%.

The present invention concerns a fuel assembly for a nuclear power boiling water reactor. The fuel assembly comprises fuel rods. At least 95% of the fuel rods comprise nuclear fuel material in the form of U enriched in 235U. At least 20% of the fuel rods belong to a first set of fuel rods. The fuel rods in this first set comprise both U enriched in 235U and Th. The first set comprises a first and a second subset of fuel rods. The ratio, with regard to weight, between Th and U, in each fuel rod of said first subset, is higher than the ratio, with regard to weight, between Th and U, in each fuel rod of said second subset. The invention also concerns a nuclear power boiling water reactor and a manner of operating such a reactor.

An annular nuclear fuel pellet in combination with an inserted discrete neutron absorber. The pellet/absorber may be compatible with existing or future nuclear fuel assembly designs. The concept involves the use of nuclear fuel (e.g., uranium dioxide or uranium silicide) formed into annular fuel pellets which can then have a discrete absorber material inserted into the center of the pin. Preferably, the discrete absorber is a non-parasitic absorber. The resulting pellet/absorber can then be stacked into a fuel rod which is arranged in a nuclear fuel assembly. Dimensioning of the annular pellet and absorber and selection of the absorber material and density can allow the concept to be tailored for various nuclear fuel applications.

The present invention relates to a nuclear fuel pellet laminate structure having enhanced thermal conductivity, including a nuclear fuel pellet; and a thermally conductive metal layer disposed above or below the nuclear fuel pellet, and a method for manufacturing the same.

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.