Nuclear fuels for nuclear reactors are described, and include nuclear fuels having a first fuel component of recycled uranium, and a second fuel component of depleted uranium blended with the first fuel component, wherein the blended first and second fuel components have a fissile content of less than 1.2 wt % of .sup.235U. Also described are nuclear fuels having a first fuel component of recycled uranium, and a second fuel component of natural uranium blended with the first fuel component, wherein the blended first and second fuel components have a fissile content of less than 1.2 wt % of .sup.235U.

A low-power nuclear reactor includes a housing and a reflector forming a reactor core. The core includes inner and outer primary tubes therein, arranged together as bayonet tubes and intended for circulating a coolant, and secondary tubes, accommodating elements of a control and protection system. The reactor further includes an intake chamber for coolant of a primary loop, and a discharge chamber for coolant of the primary loop, separated by a partition. The outer primary tubes are secured on the intake chamber's bottom, and the inner primary tubes are secured on the partition. Fuel assemblies are mounted in the inner primary tubes on suspensions, which are mounted on the discharge chamber's upper portion. The secondary tubes are sealed off from the intake and discharge chambers for the coolant of the primary loop, and an inter-tube space of the core is filled with a medium or material transparent to neutrons.

A low-power nuclear reactor includes a housing and a reflector forming a reactor core. The core includes inner and outer primary tubes therein, arranged together as bayonet tubes and intended for circulating a coolant, and secondary tubes, accommodating elements of a control and protection system. The reactor further includes an intake chamber for coolant of a primary loop, and a discharge chamber for coolant of the primary loop, separated by a partition. The outer primary tubes are secured on the intake chamber's bottom, and the inner primary tubes are secured on the partition. Fuel assemblies are mounted in the inner primary tubes on suspensions, which are mounted on the discharge chamber's upper portion. The secondary tubes are sealed off from the intake and discharge chambers for the coolant of the primary loop, and an inter-tube space of the core is filled with a medium or material transparent to neutrons.

A nuclear reactor can include a pressure vessel for containing a pressurized moderator at a first pressure. The nuclear reactor can also include a plurality of fuel channels for a coolant fluid at a second pressure. The plurality of fuel channels are fluidly connected at inlet ends thereof to a coolant supply conduit and are adapted to receive nuclear fuel bundles and to be mounted within the pressure vessel and surrounded by the moderator. The outlet ends of the fuel channels are fluidly connected to a coolant outlet conduit to enable the coolant fluid to circulate from the coolant supply conduit through the fuel channels to the coolant outlet conduit. The plurality of fuel channels maintain separation between the coolant fluid circulating within the fuel channels and the moderator.

A nuclear reactor can include a pressure vessel for containing a pressurized moderator at a first pressure. The nuclear reactor can also include a plurality of fuel channels for a coolant fluid at a second pressure. The plurality of fuel channels are fluidly connected at inlet ends thereof to a coolant supply conduit and are adapted to receive nuclear fuel bundles and to be mounted within the pressure vessel and surrounded by the moderator. The outlet ends of the fuel channels are fluidly connected to a coolant outlet conduit to enable the coolant fluid to circulate from the coolant supply conduit through the fuel channels to the coolant outlet conduit. The plurality of fuel channels maintain separation between the coolant fluid circulating within the fuel channels and the moderator.

An article formed of a metal alloy is covered at least partially with a metal hydride and a shell metal to form an assembly. Load is applied to the assembly and the assembly is heated. The shell metal deforms around the article and the metal hydride and forms a gas proof seal. The metal hydride thermally decomposes to form hydrogen gas. At least a portion of the hydrogen gas dissociates and moves as monoatomic hydrogen into the article. The metal alloy can be a zirconium metal alloy, the metal hydride can be a zirconium metal hydride, and the shell metal can be substantially copper.

A fuel assembly for use in a core of a nuclear power reactor. The assembly includes a plurality of helically twisted fuel elements supported by a frame in a fuel rod bundle. Each of the fuel elements includes fissile material. When viewed in a cross-section that is perpendicular to an axial direction of the fuel assembly, the outermost fuel elements of the fuel rod bundle define a substantially circular perimeter. The fuel elements are arranged in a mixed grid pattern that includes a first, rectangular grid pattern and a second, triangular grid pattern.

A fuel assembly for use in a core of a nuclear power reactor. The assembly includes a plurality of helically twisted fuel elements supported by a frame in a fuel rod bundle. Each of the fuel elements includes fissile material. When viewed in a cross-section that is perpendicular to an axial direction of the fuel assembly, the outermost fuel elements of the fuel rod bundle define a substantially circular perimeter. The fuel elements are arranged in a mixed grid pattern that includes a first, rectangular grid pattern and a second, triangular grid pattern.

A target irradiation system including an irradiated target removal system having a body defining a central bore, an elevator received within the central bore, and a docking surface for placing the irradiated target removal system in fluid communication with a vessel penetration of a reactor. A target canister slidably receives the radioisotope target therein, and the elevator is configured to receive the target canister. The elevator is lowered into the reactor when irradiating the radioisotope target, and the irradiated target removal system forms a portion of a pressure boundary of the reactor during target irradiation.

While typically-collected diameter data contains information for detecting some garter springs, many garter springs may not be detected without processing the diameter data. Responsively, a method for processing the diameter data to detect the garter springs has been developed. In particular, the processing involves fitting of the diameter data to a shape, determining residual errors and using the residual errors to locate garter springs.