Nuclear fuel structures and methods for fabricating are disclosed herein. The nuclear fuel structure includes a plurality of fibers arranged in the structure and a multilayer fuel region within at least one fiber of the plurality of fibers. The multilayer fuel region includes an inner layer region made of a nuclear fuel material, and an outer layer region encasing the nuclear fuel material. A plurality of discrete multilayer fuel regions may be formed over a core region along the at least one fiber, the plurality of discrete multilayer fuel regions having a respective inner layer region of nuclear fuel material and a respective outer layer region encasing the nuclear fuel material. The plurality of fibers may be wrapped around an inner rod or tube structure or inside an outer tube structure of the nuclear fuel structure, providing both structural support and the nuclear fuel material of the nuclear fuel structure.

A method for coating fibers, includes desizing sized short fibers having an average length less than or equal to 5 mm, the short fibers being made of ceramic material or carbon, sieving the desized short fibers in order to separate them from any agglomerates of sized short fibers still present, introducing the desized and sieved short fibers into a reactor, and coating the short fibers in the reactor by chemical vapor deposition in a fluidized bed.

A tow coating reactor system includes a reactor for receiving fiber tow, a wedge situated adjacent the reactor and configured to receive the tow at a tip end, such that as the tow moves across the wedge, the wedge spreads the tow into a plurality of sub-tows.

The present invention relates to a method of printing a composite material (1), for example polymeric, carbonaceous, siliconic or metallic comprising steps of: i) providing a plurality of bundles (2) of reinforcement fibres (4), wherein the reinforcement fibres (4) have a length in the range 3-50 mm and are in the number of about 1,000-100,000 in each bundle (2); ii) aligning the bundles (2) along a predetermined path (X, X′); iii) incorporating at least part of the bundles (2) into a matrix (6, 8), for example polymeric, carbonaceous, siliconic or metallic, preserving the alignment along said path (X, X′); iv) laying and solidifying at least one layer (8) of the matrix (6, 8) of step iii) to make the composite material (1).

A fiber reinforced composite component may include interleaved textile layers and ceramic particle layers coated with matrix material. The fiber reinforced composite component may be fabricated by forming a fibrous preform and densifying the fibrous preform. The fibrous preform may be fabricated by forming a first ceramic particle layer over a first textile layer, disposing a second textile layer over the first ceramic particle layer, forming a second ceramic particle layer over the second textile layer, and disposing a third textile layer over the second ceramic particle layer.

A method of forming a ceramic matrix composite (CMC) component having an engineered surface includes applying a surface slurry comprising first particulate solids in a liquid carrier to an outer surface of a ceramic fiber preform. The surface slurry is dried to remove the liquid carrier, and thus a surface slurry layer comprising the first particulate solids is formed on the outer surface. The surface slurry layer is polished to a predetermined thickness and/or surface finish. After polishing, a ceramic tape comprising second particulate solids is applied to the surface slurry layer, and pressure is applied to attach the ceramic tape to the surface slurry layer and to induce consolidation of the ceramic tape and the surface slurry layer. Thus, a multilayer surface region comprising the surface slurry layer and a ceramic tape layer is formed on the ceramic fiber preform. The ceramic fiber preform and the multilayer surface region are infiltrated with a molten material, and, upon cooling, a CMC component having an engineered surface is formed.

A method for coating a fiber tow includes moving a fiber tow across a wedge to separate the fiber tow into a plurality of sub-tows, and coating the plurality of sub-tows.

A fiber reinforced composite component may include interleaved fiber layers and ceramic particle layers coated with matrix material. The fiber reinforced composite component may be fabricated by forming a fibrous preform, needling the fibrous preform to form a plurality of z-direction fibers, and densifying the fibrous preform. The fibrous preform may be fabricated by forming a first ceramic particle layer over a first fiber layer, disposing a second fiber layer over the first ceramic particle layer, forming a second ceramic particle layer over the second fiber layer, and disposing a third fiber layer over the second ceramic particle layer.

A fiber reinforced composite component may include interleaved textile layers and ceramic particle layers coated with matrix material. The fiber reinforced composite component may be fabricated by forming a fibrous preform and densifying the fibrous preform. The fibrous preform may be fabricated by performing a silicon melt infiltration after the densification process. A plurality of pores defined by the carbon matrix material are infiltrated with a silicon material and the fibrous preform is heated to a melt temperature until a desired percentage (e.g., at least 50%) of the carbon matrix material is converted into silicon carbide or another oxidation resistant material.

A coated fiber structure for use in a ceramic matrix composite comprises a fiber and a coating system applied to and circumscribing the fiber. The coating system comprises an interface coating layer in direct contact with the fiber, the interface coating layer comprising one of boron nitride and a boron-doped pyrocarbon, at least one intermediate layer extending coaxially with and in direct contact with the interface layer, the at least one intermediate layer comprising at least one of silicon and boron nitride, and an outer layer extending coaxially with and in direct contact with the interface layer. At least one of the interface coating layer, the at least one intermediate layer, and the outer layer comprises a metallic element.