Pre-ceramic particle solutions can prepared by a Coordinated-PDC process, a Direct-PDC process or a Coordinated-Direct-PDC process. The pre-ceramic particle solution includes a polymer selected from the group consisting of (i) an organic polymer including a metal or metalloid cation, (ii) a first organometallic polymer and (iii) a second organometallic polymer including a metal or metalloid cation different from a metal in the second organometallic polymer, a plurality of particles selected from the group consisting of (a) a ceramic fuel particle and (b) a moderator particle, a dispersant, and a polymerization initiator. The pre-ceramic particle solution can be supplied to an additive manufacturing process, such as digital light projection, and made into a structure (which is pre-ceramic particle green body) that can then be debinded to form a polymer-derived ceramic sintered body. In some embodiments, the polymer-derived ceramic sintered body is a component or structure for fission reactors.

Embodiments of the invention are directed to a method for production of a nuclear fuel pellet by spark plasma sintering (SPS), wherein a fuel pellet with more than 80% TD or more than 90% TD is formed. The SPS can be performed with the imposition of a controlled uniaxial pressure applied at the maximum temperature of the processing to achieve a very high density, in excess of 95% TD, at temperatures of 850 to 1600 C. The formation of a fuel pellet can be carried out in one hour or less. In an embodiment of the invention, a nuclear fuel pellet comprises UO.sub.2 and a highly thermally conductive material, such as SiC or diamond.

The present invention relates to nuclear fuel compositions including uranium dioxide with integral fuel burnable absorber, and triuranium disilicide and a composite of uranium mononitride and triuranium disilicide with or without integral fuel burnable absorber, and methods of sintering these compositions. The sintering is conducted using SPS/FAST apparatus and techniques. The sintering time and temperature is reduced using SPS/FAST as compared to conventional sintering methods for nuclear fuel compositions. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.

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.

Disclosed are a sintered nuclear fuel pellet, a fuel rod, a fuel assembly and a method of manufacturing the nuclear fuel pellet. The pellet comprises a matrix of UO.sub.2 and particles dispersed in the matrix. The particles comprises a uranium-containing material. Each of the particles is encapsulated by a metallic coating. The uranium-containing material has a uranium density that is higher than the uranium density of UO.sub.2. The metallic coating consists of at least one metal chosen from the group of Mo, W, Cr, V and Nb.

The present disclosure provides a fuel rod and a fuel assembly, in which the fuel rod includes a first uranium pellet, a gadolinium pellet and a second uranium pellet, and the first uranium pellet, the gadolinium pellet and the second uranium pellet are each of a cylindrical shape, an end face of an end of the gadolinium pellet is connected to an end face of an end of the first uranium pellet, and an end face of an opposite end of the gadolinium pellet is connected to an end face of an end of the second uranium pellet, and the difference between an enrichment of the gadolinium pellet and an enrichment of the first uranium pellet is less than or equal to 0.5%, and the difference between an enrichment of the gadolinium pellet and an enrichment of the second uranium pellet is less than or equal to 0.5%.

The application discloses a preparation method of monocrystal uranium dioxide nuclear fuel pellets, comprising: granulating and pelleting UO.sub.2 powder to obtain UO.sub.2 pellets; then coating surfaces of the UO.sub.2 pellets with monocrystal growth additive micro powder to form core-shell structure particles; and activated-sintering the core-shell structure particles at high temperature, liquefying the monocrystal growth additive on the surface of the core-shell structure particle at high temperature and then diffusing into UO.sub.2 pellets, dissolving the UO.sub.3 in the liquid monocrystal growth additive, and recrystallizing the UO.sub.2 to form the monocrystal UO.sub.2 nuclear fuel pellets.

The present disclosure provides systems and methods for fast molten salt reactor fuel-salt preparation. In one implementation, the method may comprise providing fuel assemblies having fuel pellets, removing the fuel pellets and spent fuel constituents from the fuel assemblies, granulating the removed fuel pellets or process feed to a chlorination process, processing the granular spent fuel salt into chloride salt by ultimate reduction and chlorination of the uranium and associated fuel constituents chloride salt solution, enriching the granular spent fuel salt, chlorinating the enriched granular spent fuel salt to yield molten chloride salt fuel, analyzing, adjusting, and certifying the molten chloride salt fuel for end use in a molten salt reactor, pumping the molten chloride salt fuel and cooling the molten chloride salt fuel, and milling the solidified molten chloride salt fuel to predetermined specifications.

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-%.

Thorium-based fuel bundles 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% .sup.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.