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 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 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 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.

Abstract: A fuel assembly for a boiling water reactor, having fuel rods, a tie plate, a handle device, and at least two water rods attached to the tie plate and to the handle device. A plurality of spacers, define first passages for some of the fuel rods, and second passages for the water rods. Each water rod comprises a tube part attached to the tie plate, and a solid part attached to the handle device. The tube part permits a flow of coolant. The spacers include primary spacers and a secondary spacer. The primary spacers are attached to the tube parts. The tie plate, the water rods, the primary spacers and the handle device form a support structure carrying the weight of the fuel rods. The secondary spacer is positioned at the solid part of the respective water rod.

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: 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 invention refers to a filter (1) for separating particle from cooling water in a nuclear plant, and a fuel assembly with such a filter. The filter has an inlet end (2) and an outlet end (3) and permits through-flow of the cooling water in a main flow direction (x). The filter includes a number of sheets (4) extending in the flow direction from the inlet end to the outlet end. The sheets are arranged beside each other and form passages for the cooling water. The sheets include a first portion (4?) extending from the inlet end (2), a second portion (4?) extending from the outlet end (3), and a third portion (4??) extending between the first portion (4?) and the second portion (4?). The sheets (4) have along the first portion continuous wave-shape extending in a direction (y) transversally to the flow direction (x) and along the third portion a continuous wave-shape extending in the flow direction (x).

Abstract: The invention refers to a filter (1) for separating particle from cooling water in a nuclear plant, and a fuel assembly with such a filter. The filter has an inlet end (2) and an outlet end (3) and permits through-flow of the cooling water in a main flow direction (x). The filter includes a number of sheets (4) extending in the flow direction from the inlet end to the outlet end. The sheets are arranged beside each other and form passages for the cooling water. The sheets include a first portion (4′) extending from the inlet end (2), a second portion (4″) extending from the outlet end (3), and a third portion (4′″) extending between the first portion (4′) and the second portion (4″). The sheets (4) have along the first portion continuous wave-shape extending in a direction (y) transversally to the flow direction (x) and along the third portion a continuous wave-shape extending in the flow direction (x).

Abstract: A fuel assembly (16) for a boiling-water nuclear reactor arranged in groups with four fuel assemblies in each group and with a centrally placed control rod (17) forming a supercell. Each fuel assembly (16) includes a plurality of vertical fuel rods (12) with enriched nuclear fuel material (24), said rods being arranged between a bottom tie plate (13) and a top tie plate (14) in a surrounding vertical fuel channel (1) which is connected to a transition section (2). The transition section is provided with holes (20a-d) for by-pass flow outside the fuel assembly. The fuel assembly is characterized in that the by-pass holes are arranged in such a way that when turning the fuel assembly (16), including the transition section (2), 90.degree., 180.degree. or 270.degree. around the longitudinal axis of the fuel assembly, said holes are adapted to direct the by-pass flow away from the control rod (17).

Abstract: A fuel assembly for a light-water nuclear reactor includes a plurality of vertical fuel rods (10) which are arranged, in spaced relationship in the lateral direction, between a bottom tie plate (11) and a top tie plate (12). The bottom tie plate and the top tie plate are provided with through-holes (35) for inlet and outlet of coolant for the fuel rods. Below the bottom tie plate, in the flow path of the water, a debris catcher (36) is arranged which includes helical springs (40) that are arranged in a frame having at least two ends (37, 38) in the form of substantially parallel plates, the flat sides of which are interconnected via pins (39). The pins are arranged in spaced relationship in at least two rows between the ends in such a way that the springs, in spaced relationship or adjacent to each other, can be fixed between the rows of pins in one or more layers.

Abstract: A fuel assembly for a light-water nuclear reactor includes a plurality of vertical fuel rods (12) which are arranged, in spaced relationship in the lateral direction, between a bottom tie plate (13) and a top tie plate (14). The bottom tie plate and the top tie plate are provided with through-holes (17a) for inlet and outlet of coolant for the fuel rods. Below the bottom tie plate, in the flow path of the water, a debris catcher (18) is arranged. The debris catcher includes at least one helical spring (19) which is fixed in a holder permeable to the coolant and defining at least one slot which is formed as a plane spiral (30) or several concentric annular slots (23, 27) in which slot/slots the helical spring/helical springs is/are arranged.