Abstract: The present invention relates to a control rod blade for a boiling water reactor. The control rod blade (2) comprises a free edge portion with a recess (7) which comprises a plurality of outlets, arranged in a row, for channels (3), which are arranged to receive an absorber material (10) and a cover element (4) arranged to be attached along at least a section of the edge portion. The cover element (4) comprises a cover portion (12) arranged to seal the opening of the recess (7) and a support portion (13) arranged to, in a mounted state, abut a bottom surface in the recess (7) and to allow the formation of at least a passage (16) between the outlets of the channel (3) in the recess (7).

Abstract: The present invention relates to a fuel rod for a nuclear plant and a plenum spring arranged to be provided in a fuel rod. The fuel rod (1) comprises a cladding tube (2) sealed at its ends by end plugs (3, 4), a plurality of fuel pellets (5) stacked on each other inside the cladding tube (2) such that they form a column of pellets and said plenum spring (6) arranged to hold with a spring force the column of pellets against the lower second end of the cladding tube (2) during operation. The plenum spring (6) comprises a first length variable part (8) which abuts the uppermost located fuel pellet (5) in the column of pellets with an end portion (9), a second part (10) which allows engagement of the plenum spring (6) against an inner surface of the cladding tube (2) by a radially outwardly directed pressure and a third part (11) which allows releasing of the second part (10) of the plenum spring (6) in the cladding tube (2) during operation of the nuclear plant.

Abstract: A filter for separating particles from cooling water in a nuclear plant of light water model. The filter has an inlet end (2) and an outlet end (3) and allow flowing through of the cooling water in a flow direction z from the inlet end to the outlet end. The filter comprises a plurality of channels (5) extending mainly in the flow from the inlet end to the outlet end. Each of the channels comprise a first (6) channel section provided closer to the inlet end, a second (8) channel section arranged closer to the outlet end, and an intermediate section (7) provided between the first and the second channel section. The intermediate section (7) has an extension d2 in a direction x transversely to the flow direction, which is essentially larger than the extension d1, d3 of the first and the second channel section. The filter further comprises a separating member (9) arranged in the intermediate section.

Abstract: A control rod (2) for boiling water reactor comprising four absorber blades (6, 7, 8, 9) which form an orthogonal cross with a cruciform centre (10). The width of the absorber blades coincides with the radial direction of the control rod and the length of the absorber blades coincides with the axial direction of the control rod. Each one of the absorber blades comprises an absorber material distributed in the longitudinal direction, whereby a mean value of the quantity of absorber material per unit of length of the control rod is smaller in the upper part of the control rod than in the lower part thereof. Each one of the absorber blades comprises in its upper part (15) an inner part arranged radially inside an outer part, where the outer part is provided with absorber material whereas the inner part lacks absorber material, whereby said inner part in at least some portion constitutes at least one-fourth of the width of the absorber blade.

Abstract: The invention concerns a spacer and a fuel assembly for a nuclear reactor. The spacer has a plurality of cells (10) for holding elongated elements. The cells (10) are defined by a plurality of side portions (12). At least one of said cells (10) has at least one side portion (12) from which a flow-influencing member (20) is formed in that it is folded out from the side portion (12). The side portion (12) from which the flow-influencing member (20) is folded out comprises a first (22) and a second (24) edge surface which are connected to each other and which correspond to the directions of a first (26) and a second (28) edge of said flow-influencing member (20) in a non folded out state of the flow-influencing member (20). The first edge surface (22) has an extension in at least a first direction (14) in which a cooling medium is intended to flow. The second edge surface (24) has an extension in a direction which is perpendicular to said first direction (14).

Abstract: An absorber body arranged to absorb radiation in a nuclear energy arrangement. The absorber body comprises more than one area with a locally reduced thickness.

Abstract: A device and method for removing radioactive crud material deposited on surfaces of a nuclear fuel assembly in a nuclear plant is provided. The device comprises a container arranged to accommodate the nuclear fuel assembly, a first pumping means to pump a fluid, composed of water and ice, through the container in order to release the deposit from the nuclear fuel assembly by abrasion and to transport the released radioactive material out from the container. The first pump means also enables the feeding of a gas or steam or both to the fluid that is fed into and through the container in order to create a turbulence in the fluid. The device further comprises means, arranged in a &ggr;-radiation-dampening medium, disposed to receive the radioactive deposit transported out of the container by the fluid.

Abstract: A method for production of a nuclear fuel element with oxide base, in which the nuclear fuel with oxide base is mixed with Cr and sintered to a solid body. The amount of chrome oxide added is =>50 and <100 ppm with respect to the amount of nuclear fuel with oxide base added.

Abstract: A method and an arrangement for inspection of a test object (1) for stains or pits at its surface and measuring of any stain or pit, where the test object is arranged in an inspection fixture (3) in at least one defied position. A monitoring device (7) and a scanning device (5) are arranged at the inspection fixture and a control unit (9) for controlling the inspection is included in the arrangement. The surface of the test object is monitored by means of the monitoring device (7) and an image, produced by the monitoring device is shown at the control unit. A stain or pit shown by the monitoring device is subsequently scanned by mean of the scanning device and the depth or width of the stain or pit is calculated, dependent of the results of the scanning device.

Abstract: A method for producing a component intended to be subjected to an increased radiation in a corrosive environment, wherein the component includes an alloy which at a first, high temperature has a BCC-structure and which at a second, lower temperature has an HCP-structure, wherein the alloy includes at least one alloying element which has a low solubility in the HCP-structure and wherein the alloy is rapidly cooled from the first to the second temperature while secondary phase particles, which include said alloying element and which contribute to improve corrosion properties are separated in the HCP-structure. The rapid cooling is performed in two stages, wherein the first stage includes a rapid cooling at a relatively lower intensity and the second, subsequent stage includes a rapid cooling at a relatively higher intensity.

Abstract: The invention concerns a method and apparatus for determining the hydride content in an electrically conductive substrate by generating a first electromagnetic alternating field that at least partly penetrates the substrate which in turn produces a second alternating field that reacts with the first field. The first field is set at at least two different frequencies and measurement at the frequencies of the combined alternating field formed by the interaction of the first and second fields determines the hydride content in the substrate.

Abstract: The invention relates to a fuel assembly for a boiling water reactor which is adapted, during operation of the reactor, to allow water to flow upwards through the fuel assembly while absorbing heat from a plurality of fuel rods, whereby part of the water is transformed into steam. The fuel assembly comprises a steam channel through which the steam flows through the fuel assembly. The steam channel (16a, 16b, 16c, 16d) consists of an empty volume which at least extends through part of the fuel assembly. The fuel assembly is designed such that the water and the steam are brought to rotate around the steam channel whereby the water is thrown away from the steam channel whereas the steam which is separated from the water flows upwards through the steam channel.

Abstract: A component (1) designed for use in a light water reactor and at least partly comprised by a metal and/or a metal alloy presents a coatings (4, 7) at its outer surface (3) and its inner surface(5). The coating (4 and 7 respectively) has as its task to protect the surface (3 and 5 respectively), against oxidation, corrosion, wear and hydration. The coating (4 and 7 respectively) suitably comprises at least one of zirconium dioxide (ZrO2) and zirconium nitride (ZrN).

Abstract: The invention relates to a control rod for a boiling water reactor. The control rod comprises a top piece and a bottom piece between which an absorber part is arranged. The absorber part comprises a central part (4) and four absorber blades (3) extending from the central part (4). The absorber part comprises a channel (10) which comprises the central part and which extends along the length of the whole absorber part. The channel is surrounded by walls of a neutron-absorbing material with a long service life, for example hafnium. The channel is at least partially filled with a moderator, for example light water. During the manufacture the absorber part has undergone a heat treatment such that the hafnium alloy has been completely or partially transformed from &agr;-phase to &bgr;-phase and thereafter been rapidly cooled to &agr;-phase.

Abstract: A fuel assembly for a boiling water reactor which is designed to allow water, during operation of the reactor, to flow upwards through the fuel assembly while absorbing heat from a plurality of fuel rods, whereby part of the water is transformed into steam. The fuel assembly comprises a first steam pipe (10a) arranged with its longitudinal axis parallel to the longitudinal axis of the fuel assembly and the steam pipe comprises an inlet for the steam arranged in the first end of the steam pipe and an outlet for the steam arranged in the second end of the steam pipe. The fuel assembly also comprises a second steam pipe (10b) arranged above and at a distance from the first steam pipe such that an opening is formed between the steam pipes. The outlet of the first steam pipe has a diameter which is larger than the diameter of the inlet of the second steam pipe.

Abstract: The invention concerns a spacer (14) for a nuclear boiling water reactor. The spacer (14) comprises a plurality of cells (16) for holding or allowing elongated elements (12) to pass through the cells. Between the cells (16) there are a plurality of flow channels (18). The spacer comprises at least a plurality of deflecting members (22). The deflecting member comprises a vane (24) which extends in a direction from a cell (16) into the neighbouring flow channel (18). The vane is inclined relative to a vertical plane (26) and is wider in its upper part than in its lower part. The invention also concerns a fuel assembly for a nuclear boiling water reactor, comprising a deflecting member with vane of similar construction.

Abstract: The present invention relates to a fuel assembly for a light-water reactor with a substantially square cross section wherein the fuel assembly comprises a plurality of fuel rods (4). The fuel rods (4) extend between a bottom tie plate (5) and a top tie plate (6) and a coolant is adapted to flow upwards through the fuel assembly. At least one of the top tie plates (6) or the bottom tie plates (5) comprises flow openings (22, 22a, 22b) for the passage of the coolant and side supports (17) for supporting the fuel rods (4) in the lateral direction. The side supports (17) are designed in one and the same sheet-metal piece as the flow openings (22, 22a, 22b) and the side supports (17) are folded substantially 90° in relation to the other structure of the top tie plate (6) or the bottom tie plate (5).

Abstract: A fuel assembly for a boiling water reactor comprising full-length fuel rods (3a, 3c) with a first length extending over the height of the entire fuel assembly, and part-length fuel rods (3b) with a second length extending only in the lower part (10) of the fuel assembly, the fuel rods which have positions immediately adjacent to the part-length fuel rods being adapted so as to be bent inwards, in their upper part, towards the open region (15) which is formed above the part-length fuel rods. At least half of the fuel rods in the fuel assembly are straight.

Abstract: A fuel assembly for a boiling water reactor comprising a plurality of fuel units, stacked on top of each other, each of which comprising a plurality of fuel rods extending vertically between a top tie plate and a bottom tie plate, and means for keeping the fuel elements together. The fuel elements are surrounded by a fuel channel with a substantially square cross section. At least two of the fuel units differ from each other in regard to fuel distribution or free flow area.

Abstract: The invention concerns a method and a device for evaluating the integrity of the nuclear fuel in a nuclear plant having a reactor (1) enclosing a reactor core formed by a number of fuel cladding members (2) arranged to enclose said nuclear fuel. The value of each of a number of parameters including activity data (4) of the off-gases from the reactor is determined. The value of each of a number of second parameters including chemical data and activity data of the liquid (5) flowing through the reactor is determined. The value of each of a number of operational parameters (6) including at least one of the reactor effects, control rod position, actual fuel type, flow of off-gases, and flow of the liquid flowing through the reactor is determined. The value of the first and second parameters are standardized (7, 8) in relation to the values of said operational parameters.