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 of forming a composite component is provided. The method includes locating a fibrous preform, providing a slurry, mixing the slurry with sacrificial fibers, injecting the slurry into the fibrous preform, heating the fibrous preform, forming channels in the fibrous preform, and densifying the fibrous preform. The sacrificial fibers are suspended in the fibrous preform along an injection pathway such that heating the sacrificial fibers forms the channels along the injection pathway as the sacrificial fibers are burned away.

Polymers derived from a metallocene comprising a group IV element and at least one cyclopentadienyl group are described. Methods for preparing refractory ceramics comprising group IV carbides and/or borides using such polymer are also disclosed. In some embodiments, the method for fabricating the refractory ceramic comprises infiltrating a fiber preform with such polymer and pyrolyzing the polymeric fiber preform.

A method of fabricating a part out of composite material, includes forming a fiber texture from refractory fibers; impregnating the fiber texture for a first time with a first slip containing first refractory particles; eliminating the liquid phase from the first slip so as to leave within the texture only the first refractory particles; impregnating the fiber texture for a second time with a second slip containing second refractory particles; eliminating the liquid phase from the second slip so as to leave within the texture only the second refractory particles and obtain a fiber preform filled with the first and second refractory particles; and sintering the first and second refractory particles present in the fiber preform in order to form a refractory matrix in the preform.

A method including infiltrating a porous fiber preform with a slurry including a carrier fluid and a first plurality of solid particles wherein the first plurality of solid particles includes at least a first ceramic material, drying the slurry to form a greenbody preform, machining the greenbody preform to a target dimension, depositing a protective layer precursor including a second plurality of solid particles on the machined greenbody preform wherein the second plurality of solid particles includes at least a second ceramic material, and infiltrating the machined greenbody preform with a molten infiltrant to form a composite article including an integral protective layer.

The present disclosure provides a microwave-assisted carbon template method for preparing supported nano metal-oxides or nano metals. The method includes mixing a carbohydrate, urea, and a precursor of an oxide support with a metal salt in a container, adding a certain amount of water, and completely dissolving the solid chemicals through ultrasonic stirring to form a homogeneous solution. The method also includes performing microwave treatment on the obtained solution for approximately 0.1 minute to 60 minutes with a microwave heating power in a range of approximately 100 W to 50 kW to dehydrate and carbonize the carbohydrate and thus form a dark brown solid. The method further includes performing heat treatment on the dark brown solid at a temperature in a range of approximately 200 C. to 1100 C. in an air atmosphere for approximately 0.5 hour to 24 hours to obtain a metal-oxide supported by a porous oxide support.

A method of producing or repairing a fiber-reinforced ceramic matrix composite comprises delivering a powder composition comprising SiC particles and chopped coated SiC fibers into or onto a powder receptacle configured for composite fabrication or repair. After delivering the powder composition into or onto the powder receptacle, the SiC particles are densified to form a SiC matrix reinforced with the chopped coated SiC fibers, thereby producing or repairing a fiber-reinforced ceramic matrix composite.

A method of forming a composite article may include impregnating an inorganic fiber porous preform with a first slurry composition. The slurry composition includes particles, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to substantially immobilize the particles and yield a gelled article. The method also includes impregnating the gelled article with a second solution that includes a high char-yielding component, and pyrolyzing the high char-yielding component to yield carbon and form a green composite article. The green composite article is then infiltrated with a molten metal or alloy infiltrant to form the composite article. The molten infiltrant reacts with carbon, and the final composite article may include less residual metal or alloy than a composite article formed without using the second solution.

A ceramic matrix composite component and methods of making are described herein. The ceramic matrix composite may include a silicon containing matrix and refractory fibers embedded within the silicon containing matrix. The ceramic matrix composite component may further include a silicide layer sandwiched between the silicon containing matrix and the refractory fibers. A method of forming a ceramic matrix composite may include infiltrating a fluid that includes a refractory metal element containing compound into a fiber preform that includes fibers. The method may further include depositing the refractory metal element from the refractory metal element containing compound onto the fibers and forming, from the refractory metal element deposited onto the fibers, a refractory metal silicide.

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.