An improved retention system for retaining fuel rods in a fuel assembly is disclosed. The retention system includes a plurality of first engagement surfaces on the bottom nozzle of a fuel assembly. There is at least one engagement surface for each fuel rod. A second engagement surface is formed on the bottom end plug of each fuel rod. The first and second engagement surfaces are configured for engagement with each other for axially and laterally retaining each fuel rod within the fuel assembly. Debris deflectors may also be provided to deflect debris from coolant channels surrounding the fuel rods.

An improved retention system for retaining fuel rods in a fuel assembly is disclosed. The retention system includes a plurality of first engagement surfaces on the bottom nozzle of a fuel assembly. There is at least one engagement surface for each fuel rod. A second engagement surface is formed on the bottom end plug of each fuel rod. The first and second engagement surfaces are configured for engagement with each other for axially and laterally retaining each fuel rod within the fuel assembly. Debris deflectors may also be provided to deflect debris from coolant channels surrounding the fuel rods.

The end plug includes two parts in the form of coaxial cylinders having different diameters, the diameter of the part configured to be arranged inside the cladding is less than the cladding inner diameter by 0.06-0.08 and 2-3 mm, respectively, for interposing brazes of different types. An end plug according to the third variant is composed of three parts in the form of three successively arranged coaxial cylinders having different diameters, the diameter of the two parts configured to be arranged inside the cladding being less than the cladding inner diameter by 0.06-0.08 and 2-3 mm, respectively, for interposing brazes of two types simultaneously. The effects of the invention are safety for the environment, possibility of using the developed end plugs as an alternative for replacing plugs used in various reactors, proposal of a simplified method for manufacturing an end plug, improvements in mechanical and thermophysical properties of end plugs.

The end plug includes two parts in the form of coaxial cylinders having different diameters, the diameter of the part configured to be arranged inside the cladding is less than the cladding inner diameter by 0.06-0.08 and 2-3 mm, respectively, for interposing brazes of different types. An end plug according to the third variant is composed of three parts in the form of three successively arranged coaxial cylinders having different diameters, the diameter of the two parts configured to be arranged inside the cladding being less than the cladding inner diameter by 0.06-0.08 and 2-3 mm, respectively, for interposing brazes of two types simultaneously. The effects of the invention are safety for the environment, possibility of using the developed end plugs as an alternative for replacing plugs used in various reactors, proposal of a simplified method for manufacturing an end plug, improvements in mechanical and thermophysical properties of end plugs.

The method includes forming an inner monolithic layer from crystals of beta phase stoichiometric silicon carbide on a carbon substrate in the form of a rod by chemical methylsilane vapor deposition in a sealed tubular hot-wall CVD reactor. The method further includes forming a central composite layer over the inner monolithic layer by twisting continuous beta phase stoichiometric silicon carbide fibers into tows, transporting the tows to a braiding machine, and forming a reinforcing thread framework. A pyrocarbon interface coating is built up by chemical methane vapor deposition in a sealed tubular hot-wall CVD reactor. Then, a matrix is formed by chemical methylsilane vapor deposition in the reactor. A protective outer monolithic layer is formed from crystals of beta phase stoichiometric silicon carbide over the central composite layer by chemical methylsilane vapor deposition in a CVD reactor. And then the carbon substrate is removed from the fabricated semi-finished product.

Annular nuclear fuel rods are disclosed. The annular nuclear fuel rods include an outer cladding tube made of ceramic composite or cermet composite, an inner cladding tube made of ceramic composite or cermet composite, a nuclear fuel region located between the outer cladding tube and inner cladding tube, and an open channel for liquid coolant to flow.

Annular nuclear fuel rods are disclosed. The annular nuclear fuel rods include an outer cladding tube made of ceramic composite or cermet composite, an inner cladding tube made of ceramic composite or cermet composite, a nuclear fuel region located between the outer cladding tube and inner cladding tube, and an open channel for liquid coolant to flow.

A Gland Seal End Plug closure for a nuclear fuel rod cladding composed of silicon carbide or other materials that cannot be welded. The sealant is, preferably, made from one or more forms of pure graphite and the ram, seat and other components of the Gland Seal End Plug are formed from high temperature metallic or ceramic materials.

A Gland Seal End Plug closure for a nuclear fuel rod cladding composed of silicon carbide or other materials that cannot be welded. The sealant is, preferably, made from one or more forms of pure graphite and the ram, seat and other components of the Gland Seal End Plug are formed from high temperature metallic or ceramic materials.

A top end plug design for a nuclear fuel rod or control rod that maximizes the fuel rod length and internal volume for high burn-up, but limits plenum spring melting for eutectic formation margin. The press fit length of the top end plug is increased to increase the distance from the center of heat from the TIG welding process that seals the end plug to the cladding, to the back face of the end plug. A hole in the back of the end plug is enlarged to recover the volume loss from the press fit length increase.