A nuclear fuel assembly for a nuclear reactor core including at least one fuel cartridge having a lattice structure including an outer wall defining an interior volume, at least one flow channel extending through the interior volume of the lattice structure, at least one lattice site disposed in the interior of the lattice structure; and at least one fuel compact disposed within a corresponding one of the at least one lattice site. A cross-sectional shape of the at least one fuel compact is the same as a cross-sectional shape of the corresponding one of the at least one lattice site.

A method of making a joint between parts is provided, wherein the surface of at least one of the parts comprises aluminum oxide such as alpha aluminum oxide in the form of sapphire. A layer of aluminum nitride is provided between the surfaces of the parts where these contact. The method comprises the steps of bringing the parts into contact whereby the aluminum nitride layer is sandwiched between the parts and is in contact with the aluminum oxide surface, and performing localized heating of the aluminum nitride. The aluminum nitride is heated to at least the melting temperature of the aluminum nitride aluminum oxide eutectic, such that the aluminum nitride and adjacent aluminum oxide mix and melt to form an aluminum oxy-nitride bond. On cooling, the aluminum oxynitride forms a solid joint between the parts.

A method of making a joint between parts is provided, wherein the surface of at least one of the parts comprises aluminum oxide such as alpha aluminum oxide in the form of sapphire. A layer of aluminum nitride is provided between the surfaces of the parts where these contact. The method comprises the steps of bringing the parts into contact whereby the aluminum nitride layer is sandwiched between the parts and is in contact with the aluminum oxide surface, and performing localized heating of the aluminum nitride. The aluminum nitride is heated to at least the melting temperature of the aluminum nitride aluminum oxide eutectic, such that the aluminum nitride and adjacent aluminum oxide mix and melt to form an aluminum oxy-nitride bond. On cooling, the aluminum oxynitride forms a solid joint between the parts.

A method of making a fuel channel for a fuel assembly for a nuclear power boiling water reactor includes providing at least one first sheet of a Zr-based material of a first thickness, providing at least one second sheet of a Zr-based material of a second thickness, which is less than said first thickness, assembling at least said at least one first sheet and said at least one second sheet, such that a fuel channel is formed and such that said at least one first sheet forms a lower part of the fuel channel and such that said at least one second sheet forms a higher part of the fuel channel and such that said lower part is joined with said higher part, wherein said lower part constitutes 20-75% of the length of the fuel channel. The invention also concerns a fuel channel and a fuel assembly.

A method of making a fuel channel for a fuel assembly for a nuclear power boiling water reactor includes providing at least one first sheet of a Zr-based material of a first thickness, providing at least one second sheet of a Zr-based material of a second thickness, which is less than said first thickness, assembling at least said at least one first sheet and said at least one second sheet, such that a fuel channel is formed and such that said at least one first sheet forms a lower part of the fuel channel and such that said at least one second sheet forms a higher part of the fuel channel and such that said lower part is joined with said higher part, wherein said lower part constitutes 20-75% of the length of the fuel channel. The invention also concerns a fuel channel and a fuel assembly.

A BWR fuel assembly is elongated along a fuel assembly axis and comprises a lower tie plate, an upper tie plate axially spaced from the lower tie plate, a bundle of fuel rods extending axially between the lower tie plate and the upper tie plate, and a tubular fuel channel extending from the lower tie plate to the upper tie plate with encasing the fuel rods. The fuel assembly comprises an interaction device mounted on the lower tie plate and configured to interact with the fuel channel. The interaction device has an inactive configuration and an active configuration.

Insulated fuel assembly core with axially arranged fuel monoliths including channels and having a composition including a fissionable fuel component, exhaust support plate, exhaust shield assembly, and insulation layer. Fuel monoliths have an eccentric cylinder shape or a right circular cylinder shape with side surface keyway. The eccentric shape and/or a keyway (with associated alignment rod) provide alignment. Channels in the exhaust support plate are oriented so propellant gas flowing from the fuel monoliths through the exhaust support plate does not impinge the exhaust shield assembly. Insulated fuel assembly cores are manufactured by forming a tensioned fuel monolith stack mandrel assembly using mandrel spacers and internal tensioning components and mandrel winding an insulation layer on an outer surface of the tensioned fuel monolith stack mandrel assembly. Insulated fuel assembly cores can be incorporated into fuel assemblies of nuclear propulsion fission reactor structures, for example, a nuclear thermal propulsion engine.

Insulated fuel assembly core with axially arranged fuel monoliths including channels and having a composition including a fissionable fuel component, exhaust support plate, exhaust shield assembly, and insulation layer. Fuel monoliths have an eccentric cylinder shape or a right circular cylinder shape with side surface keyway. The eccentric shape and/or a keyway (with associated alignment rod) provide alignment. Channels in the exhaust support plate are oriented so propellant gas flowing from the fuel monoliths through the exhaust support plate does not impinge the exhaust shield assembly. Insulated fuel assembly cores are manufactured by forming a tensioned fuel monolith stack mandrel assembly using mandrel spacers and internal tensioning components and mandrel winding an insulation layer on an outer surface of the tensioned fuel monolith stack mandrel assembly. Insulated fuel assembly cores can be incorporated into fuel assemblies of nuclear propulsion fission reactor structures, for example, a nuclear thermal propulsion engine.

A method and apparatus for a fret resistant fuel rod for a Boiling Water Reactor (BWR) nuclear fuel bundle. An applied material entrained with fret resistant particles is melted or otherwise fused to a melted, thin layer of the fuel rod cladding. The applied material is made of a material that is chemically compatible with the fuel rod cladding, allowing the fret resistant particles to be captured in the thin layer of re-solidified cladding material to produce an effective and resilient fret resistant layer on an outer layer of the cladding.

A method and apparatus for a fret resistant fuel rod for a Boiling Water Reactor (BWR) nuclear fuel bundle. An applied material entrained with fret resistant particles is melted or otherwise fused to a melted, thin layer of the fuel rod cladding. The applied material is made of a material that is chemically compatible with the fuel rod cladding, allowing the fret resistant particles to be captured in the thin layer of re-solidified cladding material to produce an effective and resilient fret resistant layer on an outer layer of the cladding.