A uranium dioxide nuclear fuel pellet has about 50 to about 400 m (with respect to a 3-dimentional size) microcells formed of a ceramic material having a chemical attraction with fission products generated in the nuclear fuel pellet to absorb and trap the fission products, such that the extraction of the fission product may be retrained in a normal operation condition and that the performance of the nuclear fuel may be enhanced by mitigating PCI. In addition, highly radioactive fission products including Cs and I having a large generation amount or a long half-life enough to affect the environments can be trapped in the pellet in an accident condition, without being released outside.

A uranium dioxide nuclear fuel pellet has about 50 to about 400 m (with respect to a 3-dimentional size) microcells formed of a ceramic material having a chemical attraction with fission products generated in the nuclear fuel pellet to absorb and trap the fission products, such that the extraction of the fission product may be retrained in a normal operation condition and that the performance of the nuclear fuel may be enhanced by mitigating PCI. In addition, highly radioactive fission products including Cs and I having a large generation amount or a long half-life enough to affect the environments can be trapped in the pellet in an accident condition, without being released outside.

A nuclear fuel includes a volume of a nuclear fuel material defined by a surface, the nuclear fuel material including a plurality of grains, some of the plurality of grains having a characteristic length along at least one dimension that is smaller than or equal to a selected distance, wherein the selected distance is suitable for maintaining adequate diffusion of a fission product from a grain interior to a grain boundary in some of the grains, the nuclear fuel material including a boundary network configured to transport the fission product from at least one grain boundary of some of the grains to the surface of the volume of the nuclear fuel material.

A nuclear fuel includes a volume of a nuclear fuel material defined by a surface, the nuclear fuel material including a plurality of grains, some of the plurality of grains having a characteristic length along at least one dimension that is smaller than or equal to a selected distance, wherein the selected distance is suitable for maintaining adequate diffusion of a fission product from a grain interior to a grain boundary in some of the grains, the nuclear fuel material including a boundary network configured to transport the fission product from at least one grain boundary of some of the grains to the surface of the volume of the nuclear fuel material.

A nuclear fuel element for use in a nuclear reactor may include a plurality of metal fuel sheaths extending along a longitudinal fuel element axis and spaced apart from each other, the plurality of fuel sheaths comprising a first fuel sheath having an inner surface, an opposing outer surface and a hollow interior configured to receive nuclear fuel material. A carbon coating may be on the inner surface of the first fuel sheath. The carbon coating may include more than 99.0% wt of a carbon material including more than 20% wt of carbon nanotubes and less than about 0.01% wt of organic contaminants.

A nuclear fuel element for use in a nuclear reactor may include a plurality of metal fuel sheaths extending along a longitudinal fuel element axis and spaced apart from each other, the plurality of fuel sheaths comprising a first fuel sheath having an inner surface, an opposing outer surface and a hollow interior configured to receive nuclear fuel material. A carbon coating may be on the inner surface of the first fuel sheath. The carbon coating may include more than 99.0% wt of a carbon material including more than 20% wt of carbon nanotubes and less than about 0.01% wt of organic contaminants.

Use in a nuclear fission reactor of a sacrificial metal in a molten salt fuel containing actinide halides in order to maintain a predefined ratio of actinide trihalide to actinide tetrahalide without reducing actinide trihalide to actinide metal. A method of maintaining oxidation state of a molten salt containing actinide halides. The method comprises contacting the molten salt continuously with a sacrificial metal, the sacrificial metal being selected in order to maintain a predefined ratio of actinide trihalide to actinide tetrahalide without reducing actinide trihalide to actinide metal. A fuel tube containing a sacrificial metal is also described.

Use in a nuclear fission reactor of a sacrificial metal in a molten salt fuel containing actinide halides in order to maintain a predefined ratio of actinide trihalide to actinide tetrahalide without reducing actinide trihalide to actinide metal. A method of maintaining oxidation state of a molten salt containing actinide halides. The method comprises contacting the molten salt continuously with a sacrificial metal, the sacrificial metal being selected in order to maintain a predefined ratio of actinide trihalide to actinide tetrahalide without reducing actinide trihalide to actinide metal. A fuel tube containing a sacrificial metal is also described.

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.

Disclosed is a uranium dioxide nuclear fuel pellet, which includes metallic microcell partitions having a high protection capacity for fission products and a high thermal conductivity simultaneously. These metal microcell partitions are arranged in the nuclear fuel pellet to trap fission products. Further disclosed is a method of making the uranium dioxide nuclear fuel pellet. The method includes providing a mixture of uranium dioxide powder and additive powder of Cr-containing compound or Mo-containing compound; compressing the powder mixture to form a green pellet; and then sintering the green pellet under reducing gas environment to form the metallic microcell partitions.