Abstract: Reactor component adapted to be used in fission reactors comprising a core (2) consisting of a first material and a layer (3) consisting of a second material. The layer (3) encloses at least partly the core (2). The reactor component is characterized in that the component (1) comprises and intermediate layer (4) between the core (2) and the layer (3). The intermediate layer (4) has a material gradient that comprises a decrease of the concentration of the first material from the core (2) to the layer (3) and an increase of the concentration of the second material from the core (2) to the layer (3).

Abstract: The invention concerns a control rod configured for a nuclear power light water reactor of the BWR or PWR kind. The control rod contains absorber material. At least 50%, with respect to weight, of the absorber material that is in the control rod is in the form of hafnium hydride. The invention also concerns the use of such a control rod during operation in a nuclear power light water reactor of the BWR or PWR kind.

Abstract: A control rod for a nuclear boiling water reactor is described. The control rod has a longitudinal centre axis and control rod blades, each control rod blade having a first and a second side and being substantially parallel to the longitudinal center axis. Each control rod blade comprises an absorber material which extends from a first absorber end to a second absorber end, the distance between the first absorber end and the second absorber end defining an active length. The control rod blades are provided with distance means on the first and second sides of the control rod blades, the distance means extending a distance of at least a third of the active length of the control rod blade.

Abstract: A method of manufacturing an optimized sheet metal (1) of a zirconium based alloy is described, which optimized sheet metal (1) defines a sheet plane (BA). The method comprises the steps of providing a sheet metal (2) of a zirconium based. alloy, subjecting the sheet metal (2) to at least a preparing cold rolling and a final cold rolling, wherein the preparing cold rolling and the final cold rolling are both performed in a common rolling direction, and heat treating the sheet metal (1) between the preparing cold rolling and the final cold rolling so that the zirconium based alloy is partially re-crystallized. A method of manufacturing a spacer grid using an optimized sheet metal (1) according to the invention is also described.

Abstract: A water reactor fuel cladding tube (4) is described. The tube (4) comprises an outer layer (6) of a first zirconium based alloy and has metallurgically bonded thereto an inner layer (7) of a second zirconium based alloy. The inner layer protects (7) the cladding tube (4) against stress corrosion cracking. The second zirconium based alloy comprises tin as an alloying material, and each one of the zirconium based alloys comprises at least 96 percent by weight zirconium. The first zirconium based alloy comprises at least 0.1 percent by weight niobium. A method of manufacturing the cladding tube (4) is also described and comprises the step of co-extruding two tubes of different zirconium based alloys to produce the cladding tube (4).

Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 5% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.

Abstract: A method for manufacturing a sheet metal for use in a boiling water nuclear reactor and such a sheet metal. The method includes providing a material of a zirconium alloy that includes zirconium, and whose main alloying materials include niobium. The material is annealed so that essentially all niobium containing secondary phase particles are transformed to ?-niobium particles.

Abstract: A fuel assembly for a nuclear boiling water reactor is provided. The reactor comprises a plurality of such fuel assemblies and a plurality of control rods. Each control rod is insertable between the fuel assemblies. The fuel assembly has a longitudinal center axis and includes a plurality of elongated fuel rods and an elongated channel box. The channel box has inner sides, facing the fuel rods, and outer sides. Each inner and outer side has a longitudinal center line extending in parallel with the center axis and along the length of the channel box. A number of protrusions are distributed along the center line of at least two of the outer sides. The protrusions are configured to ensure a minimum distance between the outer side and an adjacent control rod and to enable the control rod to easily slide over and on top of the protrusions.

Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 5% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.

Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 20% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.

Abstract: A fuel channel (5) for a fuel element (1) to a fission reactor, where the fuel element comprises an inlet (9), an outlet (11) and a plurality of elongated fuel rods (3), which fuel rods each comprises a nuclear fuel and are adapted to transfer energy to a streaming medium during operation of the fission reactor. The fuel channel comprises a casing (7) adapted to surround the fuel rods between the inlet and the outlet. The casing is adapted during operation of the fission reactor to guide the streaming medium along the fuel rods from the inlet to the outlet and be subjected to irradiation from the fuel rods. The casing is manufactured from a ceramic material.

Abstract: A method of manufacturing an optimized sheet metal (1) of a zirconium based alloy is described, which optimized sheet metal (1) defines a sheet plane (BA). The method comprises the steps of providing a sheet metal (2) of a zirconium based. alloy, subjecting the sheet metal (2) to at least a preparing cold rolling and a final cold rolling, wherein the preparing cold rolling and the final cold rolling are both performed in a common rolling direction, and heat treating the sheet metal (1) between the preparing cold rolling and the final cold rolling so that the zirconium based alloy is partially re-crystallized. A method of manufacturing a spacer grid using an optimized sheet metal (1) according to the invention is also described.

Abstract: The invention refers to a nuclear fuel, a fuel element, a fuel assembly and a method of manufacturing a nuclear fuel. The nuclear fuel is adapted for use in a water cooled nuclear reactor, including light water reactors LWR, such as Boiling Water Reactors BWR and Pressure Water Reactors PWR. The nuclear fuel comprises an uranium-containing compound consisting of UN. The uranium content of the uranium-containing compound comprises less than 10% by weight of the isotope 235U. The nuclear fuel comprises an additive substantially consisting of at least one element, in elementary form or as a compound, selected from the group consisting of Zr, Mo, Si, Al, Nb and U.

Abstract: The invention relates to a final, ready to use, spacer grid for a nuclear boiling water reactor. The final spacer grid comprises: i) a spacer grid structure made of an alloy that has been formed and assembled such that it constitutes a spacer grid, and ii) an outer oxide coating on the surface of the spacer grid structure. Said alloy is a Ni base alloy that consists of the following: (table) The invention also relates to a method of manufacturing the final spacer grid according to the invention.

Abstract: A water reactor fuel cladding tube (4) is described. The tube (4) comprises an outer layer (6) of a first zirconium based alloy and has metallurgically bonded thereto an inner layer (7) of a second zirconium based alloy. The inner layer protects (7) the cladding tube (4) against stress corrosion cracking. The second zirconium based alloy comprises tin as an alloying material, and each one of the zirconium based alloys comprises at least 96 percent by weight zirconium. The first zirconium based alloy comprises at least 0.1 percent by weight niobium. A method of manufacturing the cladding tube (4) is also described and comprises the step of co-extruding two tubes of different zirconium based alloys to produce the cladding tube (4).

Abstract: A method of making Gd or Er isotopes from gaseous compounds containing —BH4 and —CH3BH3 ions involves making the Gd or Er compounds (24) in a solid state reactor (10), passing the gaseous compounds (24) to a separation process (16) to provide products enriched in the desired isotopes of Gd or Er heads and Gd or Er tails depleted in these desired isotopes and then reacting the Gd or Er heads and Gd or Er tails with chlorine in a reactor (18) to provide products of 157GdCl3, 155GdCl3 or 167ErCl3 enriched in Gd and Er isotopes.

Abstract: A fuel assembly (16) for a nuclear reactor contains fuel rods (48) which contain nuclear fuel pellets (62) held in place by a spring means or a like device (64) and end plugs (56,58) where a hollow gas absorber structure (80) is also disposed within the fuel rods (48) where at least one surface of the absorber structure (80) is coated with a catalyst material (83) that absorbs and retains at least one of hydrogen and tritium.

Abstract: A method for manufacturing a sheet metal for use in a boiling water nuclear reactor and such a sheet metal. The method includes providing a material of a zirconium alloy that includes zirconium, and whose main alloying materials include niobium. The material is annealed so that essentially all niobium containing secondary phase particles are transformed to ?-niobium particles.

Abstract: A method of producing a cladding tube for nuclear fuel for a nuclear pressure water reactor includes forming a tube which at least principally consists of a cylindrical tube component of a zirconium-based alloy, where the alloying element, except for zirconium, which has the highest content in the alloy is niobium, wherein the niobium content in weight percent is between about 0.5 and about 2.4 and wherein no alloying element, except for zirconium and niobium, in the alloy, has a content which exceeds about 0.2 weight percent. The cladding tube is then annealed such that the tube component is partly but not completely recrystallized. The degree of recrystallization in the tube component is higher than about 40% and lower than about 95%. A fuel assembly for a nuclear pressure water reactor also has a plurality of such cladding tubes.

Abstract: A method of producing a cladding tube for nuclear fuel for a nuclear pressure water reactor includes forming a tube which at least principally consists of a cylindrical tube component of a zirconium-based alloy, where the alloying element, except for zirconium, which has the highest content in the alloy is niobium, wherein the niobium content in weight percent is between about 0.5 and about 2.4 and wherein no alloying element, except for zirconium and niobum, in the alloy, has a content which exceeds about 0.2 weight percent. The cladding tube is then annealed such that the tube component is partly but not completely recrystallized. The degree of recrystallization in the tube component is higher than about 40% and lower than about 95%. A fuel assembly for a nuclear pressure water reactor also has a plurality of such cladding tubes.