Abstract: A cladding tube, a fuel rod and a fuel assembly are disclosed. The cladding tube comprises a tubular base component having an outer surface and an inner surface defining an inner space of the cladding tube housing a pile of fuel pellets. The tubular base component is made of a Zr-based alloy. A coating is applied onto the outer surface for protecting the tubular base component from mechanical wear, oxidation and hydriding. The Zr-based alloy has the following composition: Zr=balance, Al=0-2 wt %, Ti=0-20 wt %, Sn=0-6 wt %, Fe=0-0.4 wt %, Nb=0-0.4 wt %, O=200-1800 wtppm, C=0-200 wtppm, Si=0-200 wtppm, and S=0-200 wtppm. The total amount of Al+Ti+Sn>2.5 wt % and ?28 wt %.

Abstract: A computer-implemented simulation method of predicting local concentrations of constituents in coolant water anywhere along fuel rods within any fuel assembly mechanical design of a Boiling Water Reactor (BWR) potentially resulting in crud deposits on said fuel rods. The method is based on a sub-channel approach of predicting local mass fluxes of vapor and liquid in coolant water anywhere along fuel rods within any fuel assembly mechanical design of a Boiling Water Reactor (BWR) for given steady-state or transient boundary conditions. The sub-channel approach is based on the solution of mass, momentum and energy conservation equations for the vapor phase and the liquid phase, the liquid phase is represented by more than one field variable, and is specifically represented by three fields, with the vapor phase as a fourth field, consisting of droplets, a liquid base film, and disturbance waves.

Abstract: A tube grid cell (2) for a fuel bundle (8) of a nuclear reactor. The tube grid cell (2) having the length (L), comprises a cell housing (10) which has, along the longitudinal axis A, a lower section (16), an upper section (18) and a middle section (20). The middle section (20) is provided with two pairs of support members (22) and a resilient member (24) configured to generate a resilient force in an inward radial direction, the resilient member is arranged at essentially equal distance from the support members (22), and positioned approximately (120) degrees apart from the support members seen along axis A. The upper section (18) and the lower section (16) have respectively a length L1 and L2 along axis A that is larger than 0.1 L and smaller than 0.3 L, and is provided with a solid housing wall, having an even thickness and no openings, indentations or protrusions.

Abstract: A nuclear fuel pellet for a nuclear reactor is disclosed. The pellet comprises a metallic matrix and ceramic fuel particles of a fissile material dispersed in the metallic matrix. The metallic matrix is an alloy consisting of the principle elements U, Zr, Nb and Ti, and of possible rest elements. The concentration of each of the principle elements in the metallic matrix is at the most 50 molar-%.

Abstract: A fuel assembly for a nuclear reactor having an upstream minor portion defining an upstream end, a main portion, and a downstream minor portion defining a downstream end. Fuel rods extend in a flow interspace permitting a flow of coolant through the fuel assembly in contact with the fuel rods. Two elongated tubes form a respective internal passage extending in parallel with the fuel rods and enclosing a stream of the coolant. Each elongated tube having a bottom, an inlet at the upstream minor portion and an outlet at the downstream minor portion. Each elongated tube having an inlet pipe having an inlet end and an outlet end in the internal passage at a distance from the bottom, thereby forming a space in the internal passage between the outlet end and the bottom.

Abstract: A filter for separating particles from a cooling liquid in a nuclear plant is presented. The filter includes at least one passage with an inner surface, an inlet end and an outlet end, wherein the at least one passage is arranged to permit through-flow of the cooling liquid in a main flow direction (MFD) from the inlet end to the outlet end. The inner surface of the at least one passage includes at least one surface section having a structured surface forming a plurality of surface portions facing the main flow direction (MFD) of the cooling liquid and being arranged to catch the particles. Also, a fuel assembly for a nuclear plant, including a filter is presented.

Abstract: A uranium oxide fuel pellet having an inner region and an outer rim region about the inner region, and that the fuel pellet is cylindrical and the inner region and outer rim region are coaxial cylindrical regions. The outer rim region has an excess of oxygen in comparison to the inner region, wherein high burnup structure (HBS) formation will be suppressed or delayed. Preferably, the excess oxygen is obtained by a chemical treatment by immersing the pellet in hydrogen peroxide (H2O2) or potassium permanganate (KMnO4) in solution.

Abstract: A fuel assembly for a nuclear reactor, a fuel rod of the fuel assembly, and a ceramic nuclear fuel pellet of the fuel rod are disclosed. The fuel pellet includes a first fissile material of UB2, The boron of the UB2 is enriched to have a concentration of the isotope 11B that is higher than for natural B.

Abstract: A fuel assembly, a fuel rod and a cladding tube for a fuel rod for a nuclear reactor are disclosed. The cladding tube includes a tubular substrate defining an inner space for housing nuclear fuel pellets, and a surface layer applied on the tubular substrate. The tubular substrate is made of a zirconium base alloy and has a first thermal expansion coefficient. The surface layer has an alloy which consists of a major part of main elements comprising Cr and at least one of Nb and Fe, a minor part of zirconium, and possibly a residual part of interstitial elements. The alloy of the surface layer has a second thermal expansion coefficient. The concentrations of the main elements are selected so that the second thermal expansion coefficient is greater than the first thermal expansion coefficient from 20 to at least 1300° C.

Abstract: A uranium oxide fuel pellet having an inner region and an outer rim region about the inner region, and that the fuel pellet is cylindrical and the inner region and outer rim region are coaxial cylindrical regions. The outer rim region has an excess of oxygen in comparison to the inner region , wherein high burnup structure (HBS) formation will be suppressed or delayed. Preferably, the excess oxygen is obtained by a chemical treatment by immersing the pellet in hydrogen peroxide (H2O2) or potassium permanganate (KMnO4) in solution.

Abstract: A fuel assembly for a boiling water reactor having fuel rods, two or three water rods, a tie plate, spacers, a handle, and a joint arrangement. The joint arrangement is configured to transfer a vertical lifting force from the handle to the water rods. The joint arrangement includes a balancing element arranged between the water rods and the handle. The joint arrangement includes a first joint arranged between the balancing element and the handle and a set of second joints arranged between a respective one of said water rods and said balancing element. The first joint and the set of second joints are configured to allow a rotational movement of said balancing element in relation to said handle as well as in relation to said water rods in order to balance lifting forces in the water rods.

Abstract: A fuel assembly for a nuclear water reactor having an upstream end, a downstream end, and a flow interspace between the upstream and downstream ends. Fuel rods are provided in the flow interspace between the upstream and downstream ends. The flow interspace permits a flow of coolant through the fuel assembly along a flow direction from the upstream end to the downstream end. A filter device is provided to catch debris particles in the flow of coolant. The filter device has a first filter zone for a major part of the flow of coolant, and a second filter zone for a minor part of the flow of coolant. The first filter zone has a first filtering efficiency and the second filter zone has a second filtering efficiency. The second filtering efficiency is higher than the first filtering efficiency.

Abstract: A fuel assembly for a nuclear reactor, a fuel rod of the fuel assembly, and a ceramic nuclear fuel pellet of the fuel rod are disclosed. The fuel pellet includes a first fissile material of UB2, The boron of the UB2 is enriched to have a concentration of the isotope 11B that is higher than for natural B.

Abstract: A tubular ceramic component is provided for being used in a nuclear reactor. The component comprises an inner layer of silicon carbide, an intermediate layer of silicon carbide fibres in a fill material of silicon carbide, and an outer layer of silicon carbide. The intermediate layer adjoins the inner layer. The outer layer adjoins the intermediate layer. The silicon carbide of the inner layer, the fill material and the outer layer is doped and comprises at least one dopant in solid solution within crystals of the silicon carbide.

Abstract: A cladding tube for a fuel rod to be used in a nuclear fission reactor, and a method of manufacturing the cladding tube are disclosed. The cladding tube encloses fissile nuclear fuel and comprises a tubular base layer of a zirconium based alloy, and a coating layer. The coating layer is applied onto an outer border of the tubular base layer. The coating layer is formed of an amorphous alloy comprising zirconium and a further element.

Abstract: Disclosed are a sintered nuclear fuel pellet, a fuel rod, a fuel assembly and a method of manufacturing the nuclear fuel pellet. The pellet comprises a matrix of UO2 and particles dispersed in the matrix. The particles comprises a uranium-containing material. Each of the particles is encapsulated by a metallic coating. The uranium-containing material has a uranium density that is higher than the uranium density of UO2. The metallic coating consists of at least one metal chosen from the group of Mo, W, Cr, V and Nb.

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

Abstract: A method and a system includes controlling and monitoring the gas pressure in a nuclear fuel rod during filling of the fuel rod with a gas, and subsequent sealing of the fuel rod. The system includes a control unit and a length measuring system, which control unit is communicatively connected to the length measuring system. The length measuring system is configured to monitor the length of the fuel rod, and the control unit is configured to receive measurements from the length measuring system and to determine the gas pressure inside the fuel rod on the basis of variations of the length of the fuel rod. The method includes positioning an open first end of the fuel rod inside a pressure chamber, allowing gas to enter the fuel rod; pressurizing the gas in the pressure chamber at a first pressure level; closing the fuel rod; and sealing the fuel rod.

Abstract: A fuel assembly for a boiling water reactor having fuel rods, two or three water rods, a tie plate, spacers, a handle, and a joint arrangement. The joint arrangement is configured to transfer a vertical lifting force from the handle to the water rods. The joint arrangement includes a balancing element arranged between the water rods and the handle. The joint arrangement includes a first joint arranged between the balancing element and the handle and a set of second joints arranged between a respective one of said water rods and said balancing element. The first joint and the set of second joints are configured to allow a rotational movement of said balancing element in relation to said handle as well as in relation to said water rods in order to balance lifting forces in the water rods.

Abstract: A nuclear fuel pellet for a nuclear reactor is disclosed. The pellet comprises a metallic matrix and ceramic fuel particles of a fissile material dispersed in the metallic matrix. The metallic matrix is an alloy consisting of the principle elements U, Zr, Nb and Ti, and of possible rest elements. The concentration of each of the principle elements in the metallic matrix is at the most 50 molar-%.