Class / Patent application number | Description | Number of patent applications / Date published |
376438000 | Including grid | 79 |
20080232536 | Spacer and a Fuel Unit for a Nuclear Plant - The invention refers to a spacer for holding a number of elongated fuel rods intended to be located in a nuclear plant, and a fuel unit with such spacers. The spacer encloses a number of cells for receiving a respective fuel rod extending in parallel to a longitudinal axis of the respective cell. Each cell is formed by a sleeve-like member having an upper edge and a lower edge. The sleeve-like member includes a number of abutment surfaces projecting inwardly towards and extending substantially in parallel with the longitudinal axis for abutment to the fuel rod the cell. The lower edge and the upper edge have, seen transversely to the longitudinal axis, a wave-like shape with wave peaks, aligned with a respective one of said abutment surfaces, and wave valleys located between two adjacent ones of said abutment surfaces. | 09-25-2008 |
20080232537 | NUCLEAR FUEL ASSEMBLY WITH AN ADVANCED SPACER GRID - An improved nuclear fuel assembly having elongated grid straps curved in a substantially undulating wave pattern along their axial length and interleaved together to form an egg-crate configuration having a plurality of roughly square cells that support fuel rods and guide tube thimbles. The cells that support fuel rods have their outer walls curved outward to increase the contact area around the fuel rod cladding The interior straps are on a diagonal with regard to a peripheral strap and at least one cell adjacent each fuel rod cell is left empty for the unobstructed flow of coolant. Additional coolant mixing devices can be added to the empty cells. The walls of each fuel rod cell are devoid of dimples and, in one embodiment, springs. | 09-25-2008 |
20080267339 | Spacer and a Fuel Unit for a Nuclear Plant - The invention refers to a spacer for holding a number if elongated fuel rods intended to be located in a nuclear plant and to a fuel unit having such spacers. The spacer encloses a number of cells, which each has a longitudinal axis and is arranged to receive a fuel rod in such a way that the fuel rod extends in parallel with the longitudinal axis. Each cell is formed by a sleeve-like member. Each sleeve-like member is manufactured in a sheet-shaped material that is bent to the sleeve-like shape. | 10-30-2008 |
20080267340 | FUEL BUNDLE AND SPACER BAND - In various embodiments, a spacer grid for a nuclear reactor fuel bundle is provided. The grid includes a plurality of interstitial dividers that form an array of cells. Each cell is structured to retain a respective one of a plurality of fuel rods to thereby form an array of equally spaced fuel rods. The grid additionally includes a perimeter band that peripherally surrounds the dividers and is connected to opposing ends of each divider. The perimeter band includes a plurality of spring tabs formed along and extending from an edge of the perimeter band. The spring tabs extend from the edge at an angle away from the dividers such that a distal end of each spring tab will contact an interior surface of a respective one of a plurality of walls of a channel in which the arrayed fuel rods can be inserted to form the fuel bundle. | 10-30-2008 |
20090122945 | Fuel Assembly for a Pressurized-Water Nuclear Reactor - A fuel assembly for a pressurized water nuclear reactor contains a multiplicity of fuel rods which are guided in a plurality of axially spaced spacers which in each case form a square grid, composed of grid webs, with a multiplicity of cells arranged in rows and columns. In each case one control rod guide tube is guided through a number of these cells. At least one spacer is configured to be mechanically stronger in a first partial region than in a second partial region. In this second partial region, the spacer is provided with at least one resisting element which protrudes into a flow sub-channel formed between the fuel rods and increases the flow resistance. The resisting element counteracts a reduction associated with the mechanically weaker configuration, in the flow resistance in the second partial region and in this manner effects a homogenization of the hydraulic behavior of a spacer which is mechanically inhomogeneous on account of the varying mechanical configuration. | 05-14-2009 |
20090122946 | Rod assembly for nuclear reactors - A rod assembly for a fuel bundle of a nuclear reactor may include an upper end piece, lower end piece and a plurality of rod segments attached between the upper and lower end pieces and to each other so as to form an axial length of the rod assembly. The rod assembly may include an adaptor subassembly provided at given connection points for connecting adjacent rod segments or a given rod segment with one of the upper and lower end pieces. The connection points along the axial length of the rod assembly may be located where the rod assembly contacts a spacer in the fuel bundle. One (or more) of the rod segments may include an irradiation target therein for producing a desired isotope when a fuel bundle containing one (or more) rod assemblies is irradiated in a core of the reactor. | 05-14-2009 |
20090135988 | Fail-Free Fuel Bundle Assembly - A fuel bundle for a nuclear reactor core is provided. The fuel bundle may include a plurality of rods comprised of nuclear fuel rods and/or isotope production rods. Each rod includes a plurality of interconnected rod segments, wherein at least two of the rod segments of at least one rod have different outside diameters. The fuel bundle may additionally include a plurality of rod spacer grids securely retained between axially adjacent, interconnected rod segments. The rod spacer grids interconnected between axially adjacent rod segments form an array of substantially equally spaced rods. The fuel bundle may further include an elongate tubular channel in which the arrayed rods are housed. | 05-28-2009 |
20090135989 | Segmented fuel rod bundle designs using fixed spacer plates - Example embodiments are directed to a fuel rod design using segmented fuel rods that mechanically confine spacer plates to constant axial positions. Example embodiment spacer plates may be placed at axial connection points between fuel rod segments, and, when the fuel rod segments are mated, example embodiment spacer plates may be mechanically held by the mating. | 05-28-2009 |
20090135990 | Placement of target rods in BWR bundle - Exemplary embodiments of the present invention are directed to the placement of one or more isotope production rods in a fuel bundle. The placement may be based on any one of, or a combination of, numerous factors such as relative location of core-monitoring equipment, the type of radioactive isotope being produced, the half-life or length of decay of the radioactive isotope, the neutron absorption rate of the target isotope to produce the radioactive isotope, the desired specific activity of the radioactive isotope being produced, the amount of neutron flux in different areas of the fuel bundle, the duration that the target isotope/radioactive isotope is expected to remain in the reactor until removed (i.e., harvested), etc. | 05-28-2009 |
20090257546 | NUCLEAR FUEL ASSEMBLY WITH A LOCK-SUPPORT SPACER GRID - An improved grid for a nuclear reactor fuel assembly that has an egg-crate base grid as the primary support structure with each support cell of the base grid that supports a fuel rod having a lock-support sleeve that is rotatable within the support cell between a first and second orientation. In the first orientation the lock-support sleeve fits loosely within the support cell of the base grid and respectively, loosely receives the fuel rods that are loaded therein. The lock-support sleeves are then rotated to a second orientation that locks the fuel rods axially within the support cells. | 10-15-2009 |
20100166135 | DEBRIS FILTERING BOTTOM SPACER GRID WITH LOUVERS FOR PREVENTING UPLIFT OF FUEL RODS - Disclosed are a bottom spacer grid with a louver on a spring that can filter debris flowed through a channel of a lower end fitting with coolant on the lower end fitting of a nuclear fuel assembly, and can prevent uplift of fuel rods due to coolant, simultaneously. | 07-01-2010 |
20100172460 | PERFORATED PLATE SUPPORT FOR DUAL-COOLED SEGMENTED FUEL ROD - A perforated plate support supports dual-cooled fuel rods, each of which has concentric outer and inner tubes and is coupled with upper and lower end plugs at upper and lower ends thereof, and guide thimbles, each of which is used as a passage for a control rod. The perforated plate support is formed as a support plate having the shape of a flat plate, which includes internal channel holes, each of which has a diameter corresponding to an outer diameter of the inner tube, guide thimble holes, each of which has a diameter corresponding to an outer diameter of the guide thimble, and sub-channel holes around each internal channel hole. The upper or lower end of the dual-cooled fuel rod is coupled to the support plate such that the outer diameter of the inner tube is matched with the diameter of the internal channel hole. | 07-08-2010 |
20100246747 | NUCLEAR FUEL ROD SPACER GRID AND FRAMEWORK AND ASSEMBLY COMPRISING SUCH A GRID - A grid including at least two meshed grid parts intended to be superposed in a longitudinal direction, each grid part extending in a transverse plane, and the grid parts being moveable one relative to the other in at least one transverse direction between an open configuration for the insertion of nuclear fuel rods in the longitudinal direction through the grid parts, and a closed configuration allowing each fuel rod inserted through the grid parts to be clamped transversely between the grid parts. According to one aspect of the invention, the grid includes elements for transversely immobilizing the grid parts in the closed configuration, the immobilizing elements being designed to engage as the superposed grid parts are moved closer together in the longitudinal direction. | 09-30-2010 |
20100303194 | NUCLEAR FUEL ARRANGEMENT IN FUEL POOLS FOR NUCLEAR POWER PLANT - A nuclear fuel arrangement in fuel pools for nuclear power plant is disclosed, which comprises: a plurality of nuclear fuel bundles, being arranged in a tight formation; a pool partition framework, formed with a plurality of grids for storing the plural nuclear fuel bundles; wherein the partition frame has a plurality of blocks of different heights disposed at the bottoms of their corresponding grids to be used for enabling any neighboring nuclear fuel bundles in the tight formation to be ruggedly arranged with different heights. | 12-02-2010 |
20110103539 | RESILIENT SPACER FOR FUEL RODS OF NUCLEAR REACTORS - A resilient spacer for nuclear fuel rods having a plurality of cells to keep the fuel rods in position. The resilient spacer includes two spaced apart grids joined together, with each grid defining cells of the plurality of cells to keep the fuel rods in position and with each cell of the plurality of cells having springs for restricting the displacement of the fuel rods. In addition, the present invention also provides a nuclear fuel element having the spacer. | 05-05-2011 |
20110158375 | FUEL ASSEMBLY - A fuel assembly has a regular dodecagon fuel rod arrangement with a single fuel rod provided to each apex of a regular dodecagon having lines of length A. Assuming a direction within a horizontal plane is transverse, and a direction perpendicular to the transverse direction is longitudinal, regular dodecagon fuel rod arrangements are arranged in regular intervals in the transverse direction and the longitudinal direction. In the transverse direction, two adjacent regular dodecagon fuel rod arrangements are arranged having opposing two sides of the regular dodecagons parallel to each other with the distance of mA, wherein m is a nonnegative integer, apart from each other. With respect to the longitudinal direction, two adjacent regular dodecagon fuel rod arrangements are arranged so that the opposing two sides of the regular dodecagons are parallel to each other with the distance of nA, wherein n is a nonnegative integer, apart from each other. | 06-30-2011 |
20110280361 | LOWER NOZZLE FOR NUCLEAR FUEL ASSEMBLY FOR PRESSURIZED WATER REACTOR - A lower nozzle an upper end and a lower end for the lower nozzle to rest on a lower core plate of a reactor core and a lateral surface extending along a longitudinal axis from the lower end to the upper end. | 11-17-2011 |
20110311016 | LIGHT-WATER REACTOR FUEL ASSEMBLY (ALTERNATIVES), A LIGHT-WATER REACTOR, AND A FUEL ELEMENT OF FUEL ASSEMBLY - A 17×17 jacketless fuel assembly for a PWR-type light-water reactor uses thorium as the fuel. The fuel assembly has a square shape in the plan view, a seed region, a blanket region that encircles it, an upper nozzle, and a lower nozzle. The fuel elements of the seed region re arranged in the rows and columns of a square coordinate grid and have a four-lobed profile that forms spiral spacer ribs along the length of a fuel element. The blanket region contains a frame structure within which a bundle of fuel elements made from thorium with the addition of enriched uranium is positioned. The blanket region fuel elements are arranged in the two or three rows and columns of a square coordinate grid. | 12-22-2011 |
20140016735 | SPACER AND A FUEL UNIT FOR A NUCLEAR PLANT - A spacer for holding fuel rods includes cells formed by a sleeve having an upper edge and a lower edge and a number of abutment surfaces. The lower edge has a wave shape with wave peaks aligned with a respective one of the abutment surfaces, and wave valleys located between two adjacent ones of the abutment surfaces. The upper edge has a wave shape with wave peaks, which are aligned with a respective one of the abutment surfaces, and wave valleys located between two adjacent ones of the abutment surfaces. Each of the abutment surfaces extend from a respective one of the wave peaks of the upper edge to a respective one of the wave peaks of the lower edge. The sleeves abut each other in the spacer along respective connection areas to make the abutment surfaces rotatable with respect to a center point of the connection area. | 01-16-2014 |
20140254741 | SPACERS FOR NUCLEAR FUEL ASSEMBLIES - Fuel spacers include a perimeter piece and alignment strips extending within the perimeter piece. Alignment strips may have directional variation while still extending in an overall straight line between two contact points on the perimeter piece. Two alignment strips, by their relative positioning and shape, create distinct openings for fuel rods, through which rods may pass and be supported by the spacer on all sides. Alignment strips can be parallel or skew but need not physically intersect or extend at overall right angles to form such surrounding and supporting openings. Shape may be variable, such as a waveform, zig-zag, or saw-tooth. Several layers of alignment strips at any desired angle are useable in spacers, and alignment strips may be varied in length, shape, and number to account for different fuel assembly sizes and features, such as water rods. | 09-11-2014 |
20140270047 | RIB-TYPE ROUGHNESS DESIGN FOR IMPROVED HEAT TRANSFER IN PWR ROD BUNDLES - The invention pertains to a nuclear fuel assembly in a nuclear water reactor. The fuel assembly includes an array of a plurality of axially extending elongated tubular nuclear fuel elements having first and second closed ends and encapsulating a fissionable material axially along at least a portion of an interior volume thereof and an exterior of at least one of the fuel elements. The fuel elements include a cladding that extends substantially axially between the first and second closed ends. The exterior surface of the cladding is modified to include a surface texture varying axially in a prescribed pattern along at least a portion of an axial length of the cladding. The surface texture includes a plurality of ribs placed parallel to one another and circumferentially around one or more of the fuel elements. Each of the plurality of ribs has a specified height, width, and pitch between each of the plurality of ribs. | 09-18-2014 |
20140376681 | NUCLEAR FUEL ASSEMBLY HAVING A SPACER GRID WITH ONE OR MORE SEAMLESS CORNERS - A nuclear fuel assembly grid that has fuel rod support features that take up a substantial portion of the width of the corner fuel rod support cells. The nuclear fuel assembly grid has an outer strap that is joined around a corner of the grid to another outer strap segment and a mating inner strap end at the intersection with the inner strap. The juncture accommodates the width of the rod support feature, enables grid-to-grid anti-snag capabilities and facilitates the use of longitudinal feed materials and dies. | 12-25-2014 |
20150098546 | HIGH TEMPERATURE STRENGTH, CORROSION RESISTANT, ACCIDENT TOLERANT NUCLEAR FUEL ASSEMBLY GRID - The invention pertains to a nuclear fuel assembly grid or a portion or a part of the grid, such as a grid strap and/or an integral flow mixer that is at least partially constructed of a composition containing one or more ternary compounds of the general formula I: | 04-09-2015 |
20150310941 | NUCLEAR FUEL ASSEMBLY HAVING VARYING SPACING BETWEEN FUEL RODS - A nuclear fuel assembly having varying spacing between fuel rods is provided. The nuclear fuel assembly includes a bundle of fuel rods. The fuel rods are arranged in a first lattice with a non-uniform pitch between the fuel rods in the lowermost section of the fuel assembly and in a second lattice with a uniform pitch between the fuel rods in the uppermost section of the fuel assembly. | 10-29-2015 |
20160163402 | NUCLEAR FUEL ASSEMBLY SUPPORT GRID - A nuclear fuel assembly grid having a torpedo-shaped mixing vane assembly supported at each intersection of the grid straps that surrounds a fuel rod support location. The torpedo-shaped stem supports mixing vanes that extend over each of the fuel rod support locations. | 06-09-2016 |
20170236603 | HOLDING FIXTURE TO ASSIST IN ASSEMBLY OF SUPPORT GRID FOR NUCLEAR FUEL RODS AND METHOD FOR ASSEMBLING SUPPORT GRID FOR NUCLEAR FUEL RODS | 08-17-2017 |
376439000 | With coolant flow path deflecting means | 10 |
20080205579 | Distance Lattice - The invention relates to nuclear engineering and can be used for fuel clusters of nuclear reactors, for distancing and fixing fuel elements, in particular in the fuel clusters of PWR and BWR reactors. The inventive distance lattice comprises cells which are used for mounting the fuel elements or guide channels and are formed by perpendicular crossing plates. Bent blades for mixing a coolant are embodied on the plate edges at the output of said coolant. Each cell is provided with an insertable distancing element for fixing the fuel element. Said invention makes it possible to increase the turning rigidity of the cells and the stability thereof, to simultaneously reduce the size of the fixation of the fuel elements or the guiding channels in the cells and to decrease the hydraulic resistance of the lattice. | 08-28-2008 |
20090060117 | Guide thimble of dual tube type structure nuclear fuel assembly - Disclosed herein is a guide thimble of a nuclear fuel assembly, which is capable of improving the cooling performance and the stability of a nuclear fuel, preventing a flow split in dual-cooling nuclear fuel rod and guide thimble sub channels for obtaining high combustion degree and high power, and minimizing a neutron absorption section in a reaction degree region. Since the guide thimble having the dual tube type structure is adopted, a flow split in the fuel rod and guide thimble sub channels can be reduced, and the degradation in performance of nuclear fuel due to increase of a neutron absorption section can be prevented. In order for compatibility with an existing control rod, a typical guide tube is used as an inner guide thimble, and an outer guide thimble is provided outside the inner guide thimble. Thus, the guide thimble has the dual tube type structure as a whole, and is coupled to the upper and lower end fittings so that it can prevent a flow unbalance due to the flow split in the fuel rod and guide thimble sub channels. | 03-05-2009 |
20090067566 | FUEL ASSEMBLY AND PLUG-IN DISTANCE ELEMENT - This invention relates to nuclear engineering and may be used in structures of nuclear fuel assemblies, especially those used in PWR and BWR nuclear reactors. A fuel assembly comprises spacing grids comprising cells formed by orthogonal crossing plates. An insertable spacing element is installed in each cell, which is designed for fixing the fuel rod passing through the cell. In the spacing grids that are arranged between the first spacing grid and the last spacing grid downstream the coolant flow at least some cells, through which the fuel rods pass, are provided with deflectors designed for mixing the coolant flow. The insertable spacing element comprises a shell, which has a cross-section in the form of an octagon formed by four facets that are rounded and convex in the direction from the center of said element and by four facets located therebetween that are shaped and concave toward the center of the said element. The result is that cell stiffness is increased, and hydraulic resistance to a coolant flow is reduced. | 03-12-2009 |
20100034337 | BOTTOM END-PIECE HAVING AN ANTI-DEBRIS DEVICE WITH A BAFFLE FOR A NUCLEAR ASSEMBLY AND CONRRESPONDING ASSEMBLY - This bottom end-piece includes nozzles for directing the flow of water of the reactor along the lower ends of the fuel rods, the nozzles being arranged at nodes of the substantially regular network of the fuel rods, and an anti-debris device which delimits water flow channels. At least some of the water flow channels are arranged at nodes of the substantially regular network. Direction nozzles are arranged at least partially in the channels in order to delimit water passages therewith, and at least one water passage includes a first section and a second section which are mutually offset radially relative to the corresponding node of the network in order to form a baffle. | 02-11-2010 |
20100322371 | OPTIMIZED FLOWER TUBES AND OPTIMIZED ADVANCED GRID CONFIGURATIONS - A support grid for a nuclear fuel assembly, the fuel rod assembly having a generally cylindrical fuel rod with a diameter, wherein the support grid includes a frame assembly having a plurality of outer straps and a plurality tubular members and/or helical frame members. The tubular members/helical frame members have a contact portion structured to contact an adjacent helical frame member and at least one helical fuel rod contact portion with a lesser diameter. The lesser diameter is generally equivalent to the fuel rod diameter such that a fuel rod disposed in the helical frame member would engage the inner helical frame member at helical fuel rod contact portion. The helical fuel rod contact portion may have a variable pitch. | 12-23-2010 |
20110110485 | FUEL ASSEMBLY - A fuel assembly is charged in a reactor core of a nuclear reactor using a liquid metal as a coolant and includes a wrapper tube storing a plurality of fuel pins and including an entrance nozzle at a lower end thereof for introducing the coolant and an operation handling head at an upper end thereof, grids for supporting the plurality of fuel pins in the wrapper tube in the radial direction of the wrapper tube, liner tubes inserted in the wrapper tube for fixedly holding the grids in the axial direction of the wrapper tube, and peripheral flow suppressing members disposed in a peripheral flow passage extending between peripherally disposed ones of the fuel pins and the wrapper tube over a length corresponding to a heat generation length, which is a length range in the axial direction of the fuel pins storing a radioactive fuel material. | 05-12-2011 |
20110305311 | FUEL ELEMENT FOR A PRESSURIZED-WATER NUCLEAR REACTOR - In a fuel element for a pressurized-water reactor, in addition to spacers, flow-guiding structural parts are arranged. The flow guiding parts include four outer webs which, in a plane oriented perpendicularly to the central longitudinal axis, surround a square inner region of which the center point lies on the central longitudinal axis. At their lower longitudinal side facing the flowing cooling water in the operating state, the outer webs are provided with deflection lugs pointing towards the inner region and are structurally identical, wherein mutually opposite outer webs are arranged mirror-symmetrically with respect to a center plane extending in the axial direction. Such a structural part forms, at most for a number of fuel rods which is smaller than their total number in the fuel element, cells through which a respective fuel rod is guided. The number of these cells, which are situated in a row or column, is smaller than the number of the fuel rods respectively situated in this row or column. | 12-15-2011 |
20120189090 | Tiered Tie Plates and Fuel Bundles Using the Same - Example embodiments are directed to tiered tie plates and fuel bundles that use tiered tie plates. Example embodiment tie plates may include upper and lower tiered tie plates. Example embodiment tiered tie plates may have a plurality of bosses divided into groups, or tiers, having differing vertical (axial) displacement. Example embodiment fuel bundles may use tiered tie plates such that fuel rods in example bundles may originate and terminate at different vertical displacements, based upon the vertical displacement of the bosses receiving the fuel rods into the tiered tie plates. Optionally, shanks may be used to further vary fuel rod axial displacement and diameter. | 07-26-2012 |
20130230133 | ADVANCED GRID SPACER DESIGN FOR A NUCLEAR FUEL ASSEMBLY - A new, improved grid spacer for a nuclear fuel assembly is provided, comprising several straps which intersect each other alternatively to form a plurality of grid cells and fuel rods reside in some of the grid cells; the grid spacer further comprises mixing elements set at the corner of the grid cells in which the fuel rods have resided; wherein the mixing element comprises a mixing vane stretching towards the direction of the fuel rod and a flow funnel set on the bended edge of the mixing vane continuously and extending towards adjacent grid cells; the mixing vane and the flow funnel set across two sides of two adjacent grid cells respectively, and the flow funnel introduces the coolant in the grid cell at its side to the mixing vane, then the mixing vane introduces the coolant to the grid cell at its own side. | 09-05-2013 |
20140185735 | Fuel Assembly - In a fuel assembly, a plurality of fuel rods are arranged in an array of 10 rows and 10 columns in the cross section of the fuel assembly. A flow resistance member is disposed in a central portion in the cross section at upper end portions of partial length fuel rods which are a part of the fuel rods. In the flow resistance member, resistance members are each disposed between ferrules arranged in an array of 6 rows and 6 columns in the diagonal direction of the flow resistance member. Resistance members are each disposed between the ferrules in a peripheral portion of the flow resistance member. By disposing the resistance members, the pressure loss in an inner region in the cross section of the fuel assembly is increased, and the flow rate of a gas-liquid two-phase flow in an outer region surrounding the inner region is increased. | 07-03-2014 |
376440000 | For ends of fuel elements | 6 |
20110129051 | Nuclear Fuel Assembly For Boiling Water Reactor - An assembly of the type having a water channel extending along a longitudinal axis and having an upper section of larger cross-section area than a lower section and at least one fuel rod receiving groove extending longitudinally on the outer surface of the lower section, fuel rods extending longitudinally and disposed around the water channel and fixing members for fixing at least one fuel rod to the water channel in the at least one groove below the upper section. | 06-02-2011 |
20110206175 | RADIOISOTOPE PRODUCTION STRUCTURES, FUEL ASSEMBLIES HAVING THE SAME, AND METHODS OF USING THE SAME - Example embodiments are directed to tie plate attachments having irradiation targets and/or fuel assemblies having example embodiment tie plate attachments with irradiation targets and methods of using the same to generate radioisotopes. Example embodiment tie plate attachments may include a plurality of retention bores that permit irradiation targets to be contained in the retention bores. Irradiation targets may be irradiated in an operating nuclear core including the fuel assemblies, generating radioisotopes that may be harvested from the spent nuclear fuel assembly by removing example embodiment tie plate attachments. | 08-25-2011 |
20110261921 | FUEL ASSEMBLY - A fuel assembly is charged in a reactor core of a nuclear reactor using a liquid metal as a coolant, and includes a wrapper tube storing a plurality of fuel pins and including an entrance nozzle for introducing the coolant and an operation handling head, grids disposed in the wrapper tube to support the fuel pins in the radial direction of the wrapper tube, liner tubes inserted in the wrapper tube to fixedly hold the respective grids in the axial direction of the wrapper tube, and a fixing device for fixing the grids and the liner tubes in the radial direction of the wrapper tube. | 10-27-2011 |
20130272479 | LOWER END FITTING FOR NUCLEAR FUEL ASSEMBLY MADE FROM INTERSECTING METAL STRIPS - A fuel assembly including a plurality of fuel rods arranged mutually in parallel wherein the fuel rods include a fissile material, a plurality of guide tubes arranged in parallel with and interspersed amongst the fuel rods, an upper end fitting connected with upper ends of the guide tubes, and a lower end fitting connected with lower ends of the guide tubes. At least one of the upper end fitting and the lower end fitting includes a grid formed by interlocking metal strips secured together at intersections between the metal strips. | 10-17-2013 |
20130272480 | LOWER END FITTING LOCATING PINS - A nuclear reactor has a core installed on a lower core plate and formed from multiple fuel assemblies, each fuel assembly including a structural cage assembly. The structural cage assembly has an upper end fitting, mid grids, and a lower end fitting (LEF). The LEF positions the fuel assembly using four locating pins located at each corner of the LEF. The pins position the fuel assembly laterally by mating with receiving holes in the lower core plate. The locating pins have a chamfered tip with a flat end. The chamfered tip allows for a greater positioning margin when installing the fuel assembly in the core by guiding the pins into holes in the lower core plate, and the flat tip provides strength and stability in case the assembly is inadvertently rested on the tip of the pin instead of the LEF pads. | 10-17-2013 |
20140086377 | NUCLEAR FUEL ASSEMBLY TIE PLATE, UPPER NOZZLE AND NUCLEAR FUEL ASSEMBLY COMPRISING SUCH A TIE PLATE - A nuclear fuel assembly tie plate is provided. The nuclear fuel assembly tie plate is formed by intersecting strips delimiting between them tubular guide cells each for allowing a fuel rod to extend through the tie plate. The strips delimit between them tubular flow cells separate from the guide cells, each flow cell for allowing coolant flow through the tie plate. Guide cells and flow cells are arranged at nodes of a lattice defined by a repeating pattern comprising four corner nodes in a square lattice arrangement and a central node at the center of the four corner nodes, with one guide cell at each corner nodes, separated by a pair of parallel spaced strips intersecting a pair of parallel spaced strips, the two pairs of strips delimiting a four-walled central flow cell at the center node. | 03-27-2014 |
376441000 | With nonintegral fuel element contacting means | 9 |
20090041176 | SPRING MOUNTING DEVICE FOR NUCLEAR FUEL ROD - A spring mounting device in a cladding tube for nuclear fuel, comprising a spring distributor, a spring loader in the cladding tube, the distributor supplying the springs to the loader, said loader comprising a longitudinal slide to receive the spring, a pusher in order to set the spring into place in the cladding tube and is able to move in the slide, means of displacement of said pusher, said device comprising mechanical means in order to associate the actuation of the means of displacement with that of the spring distributor. | 02-12-2009 |
20090323887 | NUCLEAR CORE COMPONENT HOLD-DOWN ASSEMBLY - A plate mounted fuel assembly hold-down system that provides a defined channel for both the insertion and removal of reactor head mounted, fixed in-core detector instrumentation, provides a guided path for the fixed in-core detector during insertion, and shields the instrument shroud against coolant cross flow. The hold-down assembly includes a base plate that seats on the adapter plate of the fuel assembly and has openings that align with the control rod guide thimbles. A hollow sleeve extends through and below a central opening in the base plate to mate with the fuel assembly instrument thimble. The sleeve extends above the base plate and through and above an upper core plate of the reactor. A hold-down bar is slidably mounted on the sleeve and is restrained below the top of the sleeve. A spring is positioned around the sleeve and is captured between the hold-down bar and the base plate. | 12-31-2009 |
20100027734 | SPACER GRID FOR DUAL-COOLING NUCLEAR FUEL RODS USING INTERSECTIONAL SUPPORT STRUCTURES - A spacer grid for dual-cooling nuclear fuel rods arranged at a narrow interval. The spacer grid solves the problem in which, since the dual-cooling nuclear fuel rods are used to improve the cooling performance and stability of nuclear fuel and obtain high burnup and output, the outer diameter of each dual-cooling nuclear fuel rod is increased, and thus the gap between each dual-cooling nuclear fuel rod and the grid strap is decreased. The spacer grid includes first grid straps and second grid straps, which are crossed and arranged in transverse and longitudinal directions at regular intervals and have the shape of a flat strip, and support structures, which are fitted into the first and second grid straps around intersections of the first and second grid straps so as to support the dual-cooling nuclear fuel rods. | 02-04-2010 |
20110064184 | UNIT SPACER GRID STRAP, UNIT SPACER GRID, AND SPACER GRID FOR NUCLEAR FUEL RODS - A spacer grid for nuclear fuel rods includes a plurality of unit spacer grids stacked one on top of another. Each unit spacer grid includes a plurality of unit spacer grid straps disposed at regular intervals in a row, and a plurality of fixing grid straps connected to respective opposite ends of the unit spacer grid straps so as to fix the unit spacer grid straps. Each unit spacer grid strap has convexities alternating with each other on opposite sides thereof at regular intervals, and at least one of the convexities has a diameter greater than the others. The unit spacer grids are rotated in one direction by a 90 or 180 degree angle when being stacked. | 03-17-2011 |
20130272481 | LOWER END FITTING LOCKNUT FOR NUCLEAR FUEL ASSEMBLY - A fuel assembly includes a plurality of fuel rods comprising fissile material, a plurality of guide tubes interspersed amongst the fuel rods, an upper end fitting connected with upper ends of guide tubes, and a lower end fitting. End plugs are connected with the lower ends of the guide tubes. The end plugs have threaded male shafts extending from the lower ends of the guide tubes which pass through openings of the lower end fitting. Female lock nuts are threaded onto the threaded male shafts of the end plugs and lock with the lower end fitting to secure the lower end fitting to the lower ends of the guide tubes. The female lock nuts suitably have locking portions that are outwardly deformed into recesses of the lower end fitting to lock the lock nuts in place after tightening. Dashpot tubes may be disposed in the lower ends of the guide tubes and connected to the end plugs. | 10-17-2013 |
20130287163 | FUEL BUNDLE FOR A LIQUID METAL COOLED NUCLEAR REACTOR - In one embodiment, the fuel bundle for a liquid metal cooled reactor includes a channel, a nose assembly secured to a lower end of the channel, and a plurality of fuel rods disposed within the channel. At least one of the fuel rods has at least one guard ring surround the fuel rod and spacing the fuel rod from adjacent fuel rods. | 10-31-2013 |
20140064434 | SPACERS WITH DEFLECTION-LIMITED ROD CONTACTS FOR NUCLEAR FUEL ASSEMBLIES AND METHODS OF MAKING THE SAME - Nuclear fuel spacers include a deflection-limited elastic rod contact. Spacers may additionally include a rigid contact without elastic functionality. A degree of deflection may be chosen based on plastic deformation threshold, maximum fuel rod movement, anticipated transverse loads related to fuel assembly, inspection, handling, transportation, operation, accidents, and/or any other operating characteristic. Spacers include deflection-limited elastic contacts and/or rigid contacts in several arrangements within the spacer and/or on a single fuel rod. Spacers are compatible with a simple fabrication method that forms rigid, deflection-limiting, and elastic components from a single substrate. Nuclear fuel spacers are useable with several fuel assembly types. | 03-06-2014 |
20140064435 | NUCLEAR FUEL ASSEMBLY FOR BOILING WATER REACTOR COMPRISING A FUEL CHANNEL SPACER - A nuclear fuel assembly for boiling water reactor is provided. The nuclear fuel assembly includes a base, a head, a bundle of fuel rods extending longitudinally between the base and the head, a tubular fuel channel encasing the bundle of fuel rods, and at least one fuel channel spacer for transversely spacing the fuel assembly from an adjacent element. The or each fuel channel spacer includes a support having at least one plate and at least one corresponding leaf spring supported by the corresponding plate, the or each plate being fixed to a corresponding sidewall of the fuel channel. | 03-06-2014 |
20140241486 | FUEL ASSEMBLY - A fuel assembly includes a plurality of fuel rods arranged in parallel and including fissile material, a plurality of guide tubes arranged in parallel with and interspersed amongst the fuel rods, an upper end fitting connected with upper ends of the guide tubes, and a lower end fitting connected with lower ends of the guide tubes. Each fuel rod includes a top end and a bottom end wherein the top end extends into the upper end fitting and/or the bottom end extends into the lower end fitting. | 08-28-2014 |
376442000 | With fuel element contacting protuberance or projection | 28 |
20080219398 | Fuel Element For A Pressurized Water Reactor - A fuel element for a nuclear reactor has a fuel rod bundle, at least one spacer with cells defined by at least one web section made from a first material and several guide tubes each running through a cell and axially fixed thereto made from a second material. The first and second materials have differing thermal expansion coefficients. The connection between the guide tube and the spacer is embodied as follows: first and second projections are directly or indirectly fixed to the guide tube. The first projections are disposed in a first axial position and the second projections are arranged at a second axial position and the projections each engage in an opening through the web section to give an axially-acting undercut. | 09-11-2008 |
20090052607 | Spacer Grid for Close-Spaced Nuclear Fuel Rods - A spacer grid can be applied to close-spaced nuclear fuel rods. The spacer grid is directed to solve the problem in which, as the outer diameter of each nuclear fuel rod increases due to the use of dual-cooled nuclear fuel rods for improving cooling performance and obtaining high combustion and high output power, the gap between the neighboring nuclear fuel rods is narrowed to thus make it impossible to use an existing spacer grid. The spacer grid is a combination of unit grid straps, each of which has supports for supporting each of the nuclear fuel rods set in a narrow array and has a sheet shape, which are combined with each other. The supports are located at positions shifted from the longitudinal central line of each unit grid strap toward sub-channels. | 02-26-2009 |
20090296876 | SPACER GRID WITH SADDLE-SHAPED SUPPORTS AND CORRESPONDING NUCLEAR FUEL ASSEMBLY - A spacer grid for a nuclear fuel assembly for a light water reactor delimits a substantially regular array of cells housing nuclear fuel rods. | 12-03-2009 |
20100020916 | NUCLEAR REACTOR FUEL ASSEMBLY GRID - An elongated through-grid split sleeve is used to secure a nuclear fuel assembly spacer grid axially within a fuel assembly. The split sleeve has windows extending along an axial dimension equal to the height of the cell walls through which control rod guide thimbles extend with the sleeve having an overall axial dimension that extends the sleeve above and below the cell walls. The sleeve is inserted into the guide thimble tube openings of a welded spacer grid assembly by squeezing the split sleeve to collapse its diameter to fit into the opening. The collapsed sleeve is inserted into the opening and then released when in position, thus locking it into position within the grid. The spacer grid assembly is then assembled into the fuel assembly skeleton structure and secured into position by welding the split sleeves to the guide thimble tubes. | 01-28-2010 |
20100098208 | Anti-fretting Wear Spacer Grid With Canoe-Shaped Spring - The present invention relates to an anti-fretting wear spacer grid having a plurality of canoe-shaped springs formed thereon, wherein each of the canoe-shaped springs includes: a fuel rod-contacting part having a flat surface having a predetermined longitudinal length so as to have linear contact with the fuel rod; a curved face-connecting part formed on the upper and lower portions of the fuel rod-contacting part; a leg-connecting part formed on the end portion of the curved face-connecting part; and legs each being formed of a plate shape having a predetermined length and connecting the both sides of the leg-connecting part with one unit grid cell surface. | 04-22-2010 |
20100246748 | NUCLEAR FUEL ASSEMBLY WITH PIVOT DIMPLED GRIDS - A soft pivot dimple nuclear fuel assembly grid that utilizes a “dog bone” shaped window cutout and radius coining of edges perpendicular to coolant flow, to reduce the susceptibility of fuel rod leaking during the reactor operation. Radius coining allows the fuel rod to smoothly transition over the radiused edge to the flat rod contact section of the dimple. The symmetric “dog bone” shape enables the dimple to pivot during rod loading resulting in improved alignment between the dimple and the fuel rod, thereby minimizing scratching. The “dog bone” shape also allows for a large contact area dimple to be softer than a typical dimple which reduces contact stresses and fretting wear during reactor operations. | 09-30-2010 |
20100310034 | NUCLEAR FUEL ASSEMBLY PROTECTIVE BOTTOM GRID - A protector bottom grid for a nuclear fuel assembly that includes three laterally staggered and horizontally oriented protrusions that extend into the fuel rod cell of a support grid below a vertically oriented spring. The three staggered protrusions extend into the cell a distance that maintains a space between the protrusions and the fuel rod. The vertically oriented spring biases the fuel rod against a dimple extending from the opposite cell wall that is at an elevation just above the spring. The protrusions below the spring trap incoming debris in the area of the fuel rod end cap and protect the fuel rod cladding from fretting. | 12-09-2010 |
20110002435 | NUCLEAR FUEL ASSEMBLY SUPPORT GRID - A nuclear fuel assembly support grid formed from an array of a plurality of orthogonally arranged straps in an egg-crate configuration with angled trailing and/or leading edges that are designed to break the correlation of vortices shed from the edges of the grid straps by varying the phase of the vortices to avoid resonant vibration of the straps. | 01-06-2011 |
20110002436 | NUCLEAR FUEL ASSEMBLY SUPPORT GRID - A nuclear fuel assembly support grid formed from an array of a plurality of orthogonally arranged straps in an egg-crate configuration with angled trailing and/or leading edges that are designed to break the correlation of vortices shed from the edges of the grid straps by varying the phase of the vortices to avoid resonant vibration of the straps. | 01-06-2011 |
20110033020 | HELICALLY FLUTED TUBULAR FUEL ROD SUPPORT - A support grid for a nuclear fuel assembly, the fuel rod assembly having a generally cylindrical fuel rod with a diameter, wherein the support grid includes a frame assembly having a plurality of outer straps and a plurality of helical frame members. The helical frame members have a contact portion structured to contact an adjacent helical frame member and at least one helical fuel rod contact portion with a lesser diameter. The lesser diameter is generally equivalent to the fuel rod diameter such that a fuel rod disposed in the helical frame member would engage the inner helical frame member at helical fuel rod contact portion. The helical frame members are coupled to each other at the contact portions thereby forming a grid. The plurality of outer straps are disposed about the perimeter of the helical frame members. | 02-10-2011 |
20110080988 | FUEL BUNDLE DESIGNS USING MIXED SPACER TYPES - Example embodiment fuel bundles use multiple types of spacers within the same fuel bundle. The type for each spacer location may be determined based on the axial position of the spacer, the characteristics of the spacer type, and the location and coolant characteristics for the particular example fuel bundle including the spacers. Historic performance data for the particular bundle location, predictive modeling, etc. may be used to determine what spacer types at which locations result in the best operating conditions and margins for example fuel bundles. | 04-07-2011 |
20110200160 | SPLIT SPRING ANTI-FRETTING FUEL ROD SUPPORT STRUCTURE - A nuclear fuel assembly grid having a vertical, elongated, split spring on each wall of the cells that support fuel rods to provide eight, co-planar, point contacts of support for the fuel rod. | 08-18-2011 |
20120063562 | DUAL-COOLED FUEL ROD'S SPACER GRIDS WITH UPPER AND LOWER CROSS-WAVY-SHAPE DIMPLE - A dual-cooled fuel rod's spacer grid with upper and lower dimples, including a blocking area of a flow passage that coolant flows through is reduced and dual-cooled fuel rods are supported, and reduces a turbulent flow of the coolant as well as vibrations of the dual-cooled fuel rods, thereby lessening fretting damage done to the rods. The spacer grid includes a plurality of unit grid straps, each of which includes a body disposed in a vertical direction, an upper dimple protruding from an upper portion of the body, and a lower dimple spaced apart from the upper dimple in a downward direction and protruding from a lower portion of the body. The unit grid straps form a grid structure that have inner grid holes into which the dual-cooled fuel rods are held, and the held dual-cooled fuel rods are each supported in four directions by the upper and lower dimples. | 03-15-2012 |
20120250814 | NUCLEAR FUEL ASSEMBLY SUPPORT GRID - A spacer grid for a nuclear fuel assembly that exhibits increased crush strength. Each grid strap at the ligaments that support fuel rods has a spring or dimple to support the fuel rods under anticipated external loads during shipping and handling or in a seismic event. One or more elongated embossed ribs are provided on each of the fuel rod grid strap support ligaments to increase its moment of inertia by forming various shapes on the ligaments of the grid strap. Preferably, the ribs have a streamlined shape to prevent any excessive pressure drop. In this manner, the crush strength of a conventional short grid strap is increased without meaningful additional manufacturing costs or adverse effects to the neutron economy of the grid. | 10-04-2012 |
20130051513 | REACTOR COMPONENT - Reactor component adapted to be used in fission reactors comprising a core ( | 02-28-2013 |
20130177127 | OPTIMIZED FLOWER TUBES AND OPTIMIZED ADVANCED GRID CONFIGURATIONS - A support grid for a nuclear fuel assembly, the nuclear fuel assembly including a generally cylindrical fuel rod with a diameter, wherein the support grid includes a frame assembly having a plurality of generally circular cells and a plurality of helical frame members. The helical frame members are disposed in the cells and are structured to contact the cell as well as a fuel rod. The helical fuel rod contact portion may have a variable pitch. | 07-11-2013 |
20130202077 | Spacer Grid - A spacer grid includes interlocked straps comprising metal sheets or plates welded together to define a spacer grid having a top and bottom. The interlocked straps define a plurality of cells comprising vertical passages connecting the top and bottom of the spacer grid. The cells include: upper dimples proximate to the top of the spacer grid and distal from the mid-plane of the spacer grid; lower dimples proximate to the bottom of the spacer grid and distal from the mid-plane of the spacer grid; cantilevered upper springs having fuel rod engagement surfaces proximate to the top of the spacer grid and distal from the mid-plane of the spacer grid; and cantilevered lower springs having fuel rod engagement surfaces proximate to the bottom of the spacer grid and distal from the mid-plane of the spacer grid. | 08-08-2013 |
20130251088 | SPACERS WITH DEFLECTION-LIMITED PERIPHERAL SPRINGS FOR NUCLEAR FUEL ASSEMBLIES AND METHODS OF MAKING THE SAME - Fuel spacers include at least one specialized bathtub on an outer perimeter band. Specialized bathtubs include an elastic resistive extension and a corresponding deflection limiter on a same outer face of the perimeter band. The elastic resistive extension provides flexible resistance to the channel, and the deflection limiter provides rigid movement limitation beyond a particular threshold between channel and spacer. The positioning, spring constant, length, number, and other properties of the specialized bathtub can be chosen based on the desired fuel assembly properties and expected transverse loads in fuel shipping and operation against which specialized bathtubs resiliently protect. The specialized bathtubs can be formed from a simplified stamp operation out of the perimeter band. Bathtubs can be placed on any position(s) on the perimeter band of example embodiment spacers used in nuclear fuel assemblies. | 09-26-2013 |
20130251089 | NUCLEAR FUEL ASSEMBLY SPACER GRID AND CORRESPONDING NUCLEAR FUEL ASSEMBLY - A nuclear fuel assembly spacer grid defining a lattice of cells for receiving fuel rods is provided. The spacer grid includes a peripheral band composed of at least one peripheral strip delimiting a portion of the peripheral contour of the spacer grid, and at least one spacer grid positioning spring elastically deformable and formed in the peripheral band. | 09-26-2013 |
20130272482 | PRESSURIZED WATER REACTOR FUEL ASSEMBLY GRID - A nuclear pressurized water reactor fuel assembly grid that has a plurality of spring-like, resilient, cantilevered members that extend, substantially adjacent each other, from a wall of a grid cell that supports the fuel rods, into the support cell, with a distal end of each member being compressed by the fuel rod passing through the cell so as to exert a lateral force on the fuel rod. The plurality of cantilevered members replace conventional dimples employed in fuel assembly grid support cells. | 10-17-2013 |
20130301791 | PULSE ARC WELDING OF SPACER GRIDS TO GUIDE TUBES - A structural skeleton of a nuclear fuel assembly is assembled by inserting guide tubes through a plurality of spacer grids, and performing pulse arc welding to connect the inserted guide tubes and the spacer grids. In the structural skeleton, the spacer grids may comprise intersecting grid straps, and at least some of the grid straps may include tabs that are pulse arc welded to guide tubes. The structural skeleton may include grid retaining rings installed on the guide tubes and pinning some spacer grids, with the grid retaining rings being pulse arc welded to guide tubes. A fuel assembly includes the structural skeleton, a plurality of fuel rods comprising fissile material passing through the spacer grids, and upper and lower end fittings secured to upper and lower ends, respectively, of the guide tubes. | 11-14-2013 |
20140029713 | NUCLEAR REACTOR FUEL ASSEMBLY - A fuel assembly for a nuclear reactor that employs dissimilar materials for the fuel assembly grid and the control rod guide thimbles. The guide thimbles are secured to the grid employing a through grid cell sleeve that is welded to the grid and spot weld rings that are secured over the sleeve and welded directly to the guide tube through windows in the sleeve. | 01-30-2014 |
20140037040 | SPACER GRID FOR NUCLEAR FUEL ASSEMBLY FOR REDUCING FLOW-INDUCED VIBRATION - Disclosed herein is a spacer grid for a nuclear fuel assembly. The spacer grid has dimples for supporting fuel rods and is formed from grid strips which are assembled in a lattice shape to form lattice cells. Each grid strip has at least one hole which is formed separately from the dimples. Therefore, when coolant is drawn into the fuel assembly, a pressure difference between opposite sides of the holes is reduced, and friction generated between cut edges of the holes and the coolant reduces the magnitude of the vibration and causes a damping effect, thus reducing flow-induced vibration. The hole formed in the grid strip function to widen the range of the frequency of the flow-induced vibration caused by vortex sheddings formed around the edges of the grid strip, thus reducing the possibility of the generation of resonance with the natural frequency of the spacer grid. | 02-06-2014 |
20140037041 | SPACER GRID FOR NUCLEAR FUEL ASSEMBLY FOR REDUCING HIGH FREQUENCY VIBRATION - Disclosed herein is a spacer grid for a nuclear fuel assembly which is formed from grid strips of an improved structure, thus reducing flow-induced high-frequency vibration. The spacer grid has dimples or grid springs for supporting fuel rods and is formed from a plurality of grid strips assembled in a lattice shape to form lattice cells. Each of the grid strips has at least one slot formed in a planar portion of the grid strip separately from the dimple or grid spring. Therefore, characteristics of the vibration of the spacer grid can be set in a variety of different manners so that flow-induced high-frequency vibration can be reduced. | 02-06-2014 |
20140056398 | STRIP FOR A NUCLEAR FUEL ASSEMBLY SPACER GRID - The strip is of the type comprising a wall portion for delimiting a cell with interlaced strips, a spring formed in the strip and provided on the wall portion for biasing a fuel rod extending through the cell away from the wall portion, the spring comprising a cantilevered tab formed in the strip and a contact portion formed at least partially in the tab and protruding from the tab for contacting a fuel rod received in the cell. | 02-27-2014 |
20140072091 | STRIP FOR A NUCLEAR FUEL ASSEMBLY SPACER GRID - The strip is of the type comprising a wall portion for delimiting a cell for receiving a fuel rod and allowing flow of a coolant upwardly through the spacer grid, a spring provided on the wall portion for biasing a fuel rod extending through the cell away from the wall portion, the spring being cut out in the strip and delimited by a slot and a motion limiter formed in the strip on the wall portion to limit motion of a fuel rod received in the cell towards the wall portion against action of the spring. According to one aspect of the invention, the motion limiter is located on an edge of the slot opposite the spring and defines a risen portion on the edge. | 03-13-2014 |
20140205055 | Spacer Grids For Nuclear Reactor - A spacer grid includes intersecting straps defining cells with springs and dimples arranged to hold fuel rods passing through the cells. The direction of the springs switches at a switch point in the spacer grid that is not at the center of the spacer grid. The intersecting straps may include a first set of mutually parallel straps including a first transition strap and a second set of mutually parallel straps including a second transition strap, with the second set intersecting the first set. The springs of the first set of mutually parallel straps face away from the first transition strap, and the springs of the second set of mutually parallel straps face away from the second transition strap. The outer straps in some embodiments include dimples but not springs. | 07-24-2014 |
20150357053 | CRUSH RESISTANT NUCLEAR FUEL ASSEMBLY SUPPORT GRID - A spacer grid design for a nuclear fuel assemblies that exhibits increased crush strength. The walls of the grid straps that surround the fuel elements have a number of dimples and/or springs with the flat surfaces of those walls formed with a plurality of emboss geometries that are formed in a symmetrical pattern with the pattern covering substantially an entire area of the wall except for the contact surfaces of the dimples and springs that interface with the fuel rods. | 12-10-2015 |