With Fuel Element Contacting Protuberance Or Projection Patents (Class 376/442)
  • Patent number: 7822166
    Abstract: A fuel assembly for a boiling water reactor contains a plurality of fuel rods maintained laterally by spacers and surrounded by a fuel assembly case. The outer walls of a spacer are provided with projecting elements that maintain a minimum space between the outer surface of the spacer and the fuel assembly case, the opening span of a spacer being smaller than the internal width of the fuel assembly case. The fuel assembly is characterized in that the spacer is maintained in an off-center position by a force acting laterally thereon such that an external space located between an outer surface of the spacer associated with the outer surface of a central cell and the fuel assembly case is narrower than an internal gap opposite the external space and oriented towards the center or towards a control element disposed at the center.
    Type: Grant
    Filed: April 1, 2005
    Date of Patent: October 26, 2010
    Assignee: Areva NP GmbH
    Inventors: Peter Bucheit, Hans-Peter Fuchs, Matthias Rudolf
  • Publication number: 20100246748
    Abstract: 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.
    Type: Application
    Filed: March 27, 2009
    Publication date: September 30, 2010
    Applicant: Westinghouse Electric Company, LLC
    Inventors: Michael L. Lewis, Michael L. Boone, Howard A. Pendley, II
  • Patent number: 7804931
    Abstract: 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.
    Type: Grant
    Filed: January 10, 2005
    Date of Patent: September 28, 2010
    Assignee: Westinghouse Electric Sweden AB
    Inventors: Sture Helmersson, Leif Larsson, Olov Nylund, H{dot over (a)}kan Söderberg
  • Patent number: 7769125
    Abstract: A spacer grid used for placing and supporting fuel rods in nuclear reactor fuel assemblies is disclosed. The spacer grid of this invention has a plurality of inner strips intersecting each other to form a plurality of guide tube cells and a plurality of fuel rod cells, with a plurality of mixing blades projecting upward from the inner strips at intersections of the inner strips. The spacer grid further includes a plurality of perimeter strips to encircle the intersecting inner strips. Each of the perimeter strips is fabricated with a plurality of unit intermediate strips and a plurality of unit corner strips, with a grid spring provided on each of the unit strips.
    Type: Grant
    Filed: February 5, 2004
    Date of Patent: August 3, 2010
    Assignee: Korea Atomic Energy Research Institute
    Inventors: Kyung-Ho Yoon, Heung-Seok Kang, Hyung-Kyu Kim, Kee-Nam Song, Yeon-Ho Jung, Tae-Hyun Chun, Dong-Seok Oh, Wang-Kee In
  • Publication number: 20100098208
    Abstract: 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.
    Type: Application
    Filed: January 9, 2008
    Publication date: April 22, 2010
    Applicant: Korea Nuclear Fuel Co., Ltd.
    Inventors: Kyong-bo EOM, Kyu-Tae Kim, Jung-min Suh, Shin-ho Lee, Nam-gyu Park, Joon-kyoo Park, Jin-sun Kim, II-kyu Kim, Seong-ki Lee, Joon-hyung Choi
  • Publication number: 20100020916
    Abstract: 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.
    Type: Application
    Filed: June 18, 2007
    Publication date: January 28, 2010
    Inventors: Richard P. Broders, Paul M. Evans
  • Publication number: 20090296876
    Abstract: A spacer grid for a nuclear fuel assembly for a light water reactor delimits a substantially regular array of cells housing nuclear fuel rods. The spacer grid further including supporting members which project into the cells from the peripheral belt of walls. The inner surface of at least one supporting member has before irradiation a concave shape in a plane transverse to the longitudinal direction. The inner surface of the contact part of the supporting member also has a convex shape in a longitudinal plane orientated radially with respect to the central axis of the corresponding cell before irradiation.
    Type: Application
    Filed: December 18, 2007
    Publication date: December 3, 2009
    Applicant: AREVA NP
    Inventors: Berenger D'Uston De Villereglan, Claude Bois, Bruno Bonnamour, Michel Bonnamour
  • Patent number: 7623612
    Abstract: A bi-alloy spacer grid (BASG) is provided with grid straps and springs made using different zirconium alloys. The grid straps are made from a relatively low growth zirconium alloy, and the springs are made from a relatively high growth zirconium alloy. The springs are coupled to the grid straps by welding, mechanical interference, or secondary forming in place. When subjected to irradiation, the springs grow relative to the grid straps thereby maintaining contact with the fuel rod cladding, while the grid straps resist growth to maintain structural stability of the entire fuel assembly. The optimized balance of the high growth springs and low growth grid straps mitigates the formation of gaps between the fuel rods and grid support structures). The growth properties of the grid straps and springs may be further controlled through optional different fabrication processes.
    Type: Grant
    Filed: March 27, 2006
    Date of Patent: November 24, 2009
    Assignee: Westinghouse Electric Co. LLC
    Inventors: Michael A. Marzean, Quang M. Nguyen
  • Patent number: 7577229
    Abstract: A resilient bush for frictionally engaging a centering pin of the fuel assembly is fixed in each of the through-holes of at least one of the end-pieces of the fuel assembly. The resilient bush comprises an annular member which has a portion for fixing in the hole of the end-piece and resilient arms which are separated by apertures. The flexible arms of the resilient bush comprise, in a free end portion, a supporting surface which projects radially inside the bush whose diameter is smaller than the diameter of a centering pin of the fuel assembly.
    Type: Grant
    Filed: December 7, 2004
    Date of Patent: August 18, 2009
    Assignee: Areva NP
    Inventors: Jean-Luc Chambrin, Angelo Beati, Guy Gentet
  • Patent number: 7561654
    Abstract: In a fuel assembly for a nuclear reactor, a plurality of nuclear fuel rods and at least one fuel rod spacer assembly supporting the fuel rods in an organized array. The fuel rod spacer assembly includes a guide at a leading edge of the fuel rod spacer assembly. The guide is angled towards the fuel rod for directing debris to open passages in the fuel rod spacer assembly.
    Type: Grant
    Filed: June 16, 2006
    Date of Patent: July 14, 2009
    Assignee: Global Nuclear Fuel - Americas, LLC
    Inventors: Mason Dennis Makovicka, Michael Thomas Kiernan
  • Publication number: 20090052607
    Abstract: 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.
    Type: Application
    Filed: June 26, 2008
    Publication date: February 26, 2009
    Applicant: KOREA ATOMIC ENERGY RESEARCH INSTITUTE
    Inventors: Kang-Hee Lee, Hyung-Kyu Kim, Kyung-Ho Yoon, Young-Ho Lee, Jae-Yong Kim, Tae-Hyun Chun, Wang-Kee In, Dong-Seok Oh, Chang-Hwan Shin
  • Patent number: 7469030
    Abstract: A spacer grid for a fuel assembly in a light-water-cooled nuclear reactor, for providing the transverse retention of a bundle of fuel rods in mutually parallel arrangements, having an array of cells juxtaposed and placed in a regular lattice, each bounded and separated from neighboring cells by at least one peripheral wall which is open at two opposed ends, along the direction of an axis of the cell, so as to receive a fuel rod of cylindrical general shape passing along the cell along its axis parallel to the peripheral wall.
    Type: Grant
    Filed: March 25, 2003
    Date of Patent: December 23, 2008
    Assignee: Framatome ANP
    Inventors: Bruno Bonnamour, Michel Bonnamour, Jacques Gauthier, Hubert Salaun
  • Publication number: 20080219398
    Abstract: 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.
    Type: Application
    Filed: October 30, 2007
    Publication date: September 11, 2008
    Applicant: AREVA NP GmbH
    Inventors: Matthias Rudolph, Hans-Peter Fuchs, Erhard Friedrich
  • Patent number: 7421056
    Abstract: A spacer for a fuel element of a boiling water reactor contains cells that are formed by inner partitions, which are disposed in a crisscross manner, and by outer partitions, which surround the inner partitions in a frame-like manner. A guiding device is placed on the spacer and contains a flow-through opening, which is located in an outer partition. The guiding device also contains a guiding element which, when viewed in the direction of flow of the coolant, is located in front of the flow-through opening, and is situated at a distance from the inner side of the outer partition, and interacts with the flow-through opening like a venturi nozzle.
    Type: Grant
    Filed: September 10, 2004
    Date of Patent: September 2, 2008
    Assignee: Areva NP GmbH
    Inventor: Michael Liebler-Ranzus
  • Patent number: 7149273
    Abstract: A method of fabricating a fuel assembly grid that includes providing a plurality of interconnected straps that form a lattice pattern, wherein the lattice pattern of the straps defines a plurality of cells, providing a sleeve that has a cylindrical portion and a flared portion, and inserting the sleeve into at least one of the cells. When inserted, at least a portion of the cylindrical portion of the sleeve will reside inside the cell and the flared portion will extend above the top end of the cell and overhang the perimeter of the cell. The flared portion is melted and flows over and fuses to the straps that define the cell. The straps may include weld tabs over which the melted material flows and to which it fuses. The melting and fusing steps also preferably cause any loose straps surrounding the cell to become attached to the sleeve.
    Type: Grant
    Filed: November 16, 2004
    Date of Patent: December 12, 2006
    Assignee: Westinghouse Electric Co LLC
    Inventors: Paul M. Evans, Gary C. Crabtree, Kevin G. Guthrie, Phillip L. Hazlett
  • Patent number: 7085340
    Abstract: A nuclear fuel assembly having a parallel array of elongated fuel elements supported between an upper and lower nozzle. Main support grids are substantially evenly spaced along the elongated dimension of the assembly to maintain the spacing between fuel elements. A plurality of auxiliary vibration-resistant grids respectively positioned between the main support grids in the middle third elongated dimension of the fuel elements, that are smaller in height and provide a larger fuel element contact area than the main support grids.
    Type: Grant
    Filed: September 5, 2003
    Date of Patent: August 1, 2006
    Assignee: Westinghouse Electric Co, LLC
    Inventors: Mark P. Goldenfield, Quang M. Nguyen, Gregory E. Settle, Radu O. Pomirleanu, Abdelaziz M. Elmahdi, Lewis A. Walton, Raymond W. Brashier
  • Patent number: 6914955
    Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving apertures formed therein. Each aperture has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.
    Type: Grant
    Filed: January 8, 2004
    Date of Patent: July 5, 2005
    Assignee: Babcock & Wilcox Canada Ltd.
    Inventor: Richard G. Klarner
  • Patent number: 6912264
    Abstract: A fuel element for a nuclear reactor has fuel rods with nuclear fuel guided through spacers. The spacers are equipped with devices that exert a swirling impulse upon a coolant flowing along the fuel rods. In order to present as little flow resistance as possible for the coolant, these swirl-introducing devices have the form of a vane with a spoonlike or bladelike shape and they extend into the coolant flow. Owing to the shape—here the vane is curved in the longitudinal and in the transverse directions—practically all cross sections of the vane have such a high geometrical moment of inertia that even a vane made of a thin sheet metal is sufficiently rigid. Fuel elements configured according to the invention are particularly suitable for use in boiling water nuclear reactors.
    Type: Grant
    Filed: August 15, 2003
    Date of Patent: June 28, 2005
    Assignee: Framatome ANP GmbH
    Inventors: Werner Meier, Peter Rau
  • Patent number: 6819733
    Abstract: An improved grid for use in a fuel assembly of a nuclear reactor includes a plurality of straps that are interconnected with one another in a lattice fashion to define a plurality of cells, with the straps being configured to include a plurality of relatively more compliant springs and a plurality of relatively less compliant dimples, whereby each cell includes only one pair of springs and one pair of dimples disposed therein. The springs and dimples are contoured to engage a fuel rod or a thimble tube disposed within the cell. Each spring directly confronts one of the dimples to provide confronting pairs of features that engage the fuel rods or thimble tubes, with each cell including two pairs of confronting features. The ligaments of the springs and dimples extend in a direction generally perpendicular to the direction of coolant flow through the reactor in order to minimize pressure drop.
    Type: Grant
    Filed: May 15, 2002
    Date of Patent: November 16, 2004
    Assignee: Westinghouse Electric Company LLC
    Inventors: Richard P. Broders, Stephen C. Hatfield, Michael L. Martin, Paul F. Joffre, Zeses E. Karoutas, Patrick A. Perrotti
  • Patent number: 6810101
    Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving aperture formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: October 26, 2004
    Assignee: Babcock & Wilcox Canada, Ltd.
    Inventor: Richard G. Klarner
  • Patent number: 6744842
    Abstract: A fuel assembly for a pressurized-water reactor includes fuel rods held in cells of spacers, control rod guide tubes, and a headpiece and a foot piece, by which it is fixed to upper and lower core grids, respectively. A spacer having a first part, which lies on a radially outer side with respect to a longitudinal center axis of the fuel assembly, and a second part, which lies on a radially inner side and is completely surrounded by the first part are included to reduce the size of gaps between fuel assemblies. The second part is formed of Zircaloy. The first part is made of a metallic material, and when compared to the Zircaloy of the second part, has a lower growth in the radial direction, caused by neutron radiation and a higher coefficient of thermal expansion.
    Type: Grant
    Filed: September 19, 2002
    Date of Patent: June 1, 2004
    Assignee: Framatome ANP GmbH
    Inventors: Norbert Schmidt, Peter Rau, Erika Herzog
  • Patent number: 6744843
    Abstract: A side-slotted nozzle type double sheet spacer grid for nuclear fuel assemblies is disclosed. The spacer grid includes intersecting inner strips and four perimeter strips. Each inner strip has unit strip parts, each fabricated by integrating two unit sheet parts together into a single structure, such that the two unit sheet parts face each other and a nozzle type coolant channel is defined between the two unit sheet parts. Each perimeter strip is fabricated by integrating an inner thin sheet having the unit sheet parts with a flat outer thin sheet having a width corresponding to the width of the inner thin sheet into a single structure. The coolant channel has one or more outlets formed by cutting an upper portion of one of the two unit sheet parts of each unit strip part. Each unit sheet part has a slot longitudinally formed on each side surface of a spring that is projected from the unit sheet part to support a fuel rod within a four-walled cell.
    Type: Grant
    Filed: May 30, 2003
    Date of Patent: June 1, 2004
    Assignees: Korea Atomic Energy Research Institute, Korea Hydro & Nuclear Power Co., Ltd.
    Inventors: Heung Seok Kang, Kyung Ho Yoon, Hyung Kyu Kim, Kee Nam Song, Yeon Ho Jung, Tae Hyun Chun, Dong Seok Oh, Wang Kee In
  • Patent number: 6735268
    Abstract: The spacer/water rod retention assembly includes a clip secured to the spacer having a slot perimetrically bounded both axially and laterally spaced portions of the clip. A resilient tab projects from one side portion into the slot. A water rod has a projecting tab which, upon relative rotation of the spacer and water rod, engages and deflects the clip tab to enable the water rod tab to reside in the clip slot. When the clip tab returns to its initial position, substantial relative rotation between the water rod and spacer is precluded and axial connection between the spacer and water rod is assured. In another form, the water rod tab projects into a slot of the clip. An adjacent water rod prevents rotation of the water rod tab in the opposite direction, thereby capturing the spacer and water rod and preventing relative axial movement.
    Type: Grant
    Filed: April 10, 2002
    Date of Patent: May 11, 2004
    Assignee: General Electric Company
    Inventors: Russell P. Higgins, David G. Smith
  • Patent number: 6728329
    Abstract: A fuel assembly having a plurality of fuel rods arranged in a square lattice array. The fuel rods include a plurality of short-length fuel rods each having a fuel active length shorter than that of each of remaining ones of the fuel rods. At least one water rod is arranged in a region in which one or more of the fuel rods are arrangeable in the array, and a plurality of fuel spacers are provided at a plurality of positions in the axial direction for holding the plurality of fuel rods and the at least one water rod, with mutual radial intervals therebetween being kept immovable. The plurality of short-length fuel rods include at least one first short-length fuel rod arranged in the outermost peripheral region of the square lattice array. Each of the plurality of fuel spacers include a plurality of cylindrical members.
    Type: Grant
    Filed: May 30, 2002
    Date of Patent: April 27, 2004
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Atsuya Hirano, Satoshi Kanno, Makoto Irube, Hideki Kurosaki, Yasuhiro Aizawa, Takashi Fukumoto
  • Patent number: 6721384
    Abstract: A spacer grid for nuclear fuel assemblies is disclosed. This spacer grid has a plurality of side weld supports, that is, main supports, upper sub-supports and lower sub-supports, on its interlaced inner straps, with two flow mixing vanes integrally extending upward from each of the main supports. This spacer grid is fabricated by seam-welding the interlaced first and second inner straps to each other along the upper axial junction lines of the crossing main and upper sub-supports at the top of the intersections, and along the lower axial junction lines of the crossing lower sub-supports at the bottom of the intersections, thus forming side weld lines at the intersections.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: April 13, 2004
    Assignees: Korea Atomic Energy Research Institute, Korea Hydro & Nuclear Power Co., Ltd.
    Inventors: Dongseok Oh, Taehyun Chun, Wangkee In, Keenam Song, Hyungkyu Kim, Heungseok Kang, Kyungho Yoon, Younho Jung
  • Patent number: 6714619
    Abstract: A spacer grid for use in a nuclear fuel assembly has double-deflected vanes that guide an axial flow of coolant around fuel rods and thereby generate swirl flow. The vanes each have a double bend projecting upwardly from first inner straps and projecting toward one fuel rod. The vanes are sufficiently wide at their bases to prevent inadvertent deformation due to contact with fuel rods during an insertion of fuel rods into the cells. The vanes also make a smooth variation in the cross-sectional area of the coolant channel at the outlet of the spacer grid, thus reducing a loss of pressure during reactor operation.
    Type: Grant
    Filed: August 7, 2002
    Date of Patent: March 30, 2004
    Assignees: Korea Atomic Energy Research Institute, Korea Kydro & Nuclear Power Co., Ltd.
    Inventors: Dongseok Oh, Taehyun Chun, Wangkee In, Keenam Song, Hyungkyu Kim, Heungseok Kang, Kyungho Yoon, Younho Jung
  • Patent number: 6707872
    Abstract: A spacer grid used for placing and supporting fuel rods in nuclear reactor fuel assemblies is disclosed. The spacer grid of this invention has a plurality of grid springs designed to have an optimal shape of their vertical support parts, thus reducing fretting wear of the fuel rods caused by contact of the fuel rods with the grid springs. The grid spring has a vertical support part and a fuel rod support part. The vertical support part includes upper and lower base parts extending downward and upward from the central portions of the top and bottom edges of an opening formed at the central portion of a unit strip, and two bridge parts branched from the upper base part and extending symmetrically downward until they are united at the lower base part. The fuel rod support part includes a conformal support part brought into surface contact with the external surface of a fuel rod.
    Type: Grant
    Filed: December 7, 2001
    Date of Patent: March 16, 2004
    Assignees: Korea Atomic Energy Research Institute, Korea Hydro & Nuclear Power Co., Ltd.
    Inventors: Kyung Ho Yoon, Heung Seok Kang, Hyung Kyu Kim, Kee Nam Song, Youn Ho Jung, Tae Hyun Chun, Dong Seok Oh, Wang Kee In, Gyung Jin Park
  • Publication number: 20030215048
    Abstract: An improved grid for use in a fuel assembly of a nuclear reactor includes a plurality of straps that are interconnected with one another in a lattice fashion to define a plurality of cells, with the straps being configured to include a plurality of relatively more compliant springs and a plurality of relatively less compliant dimples, whereby each cell includes only one pair of springs and one pair of dimples disposed therein. The springs and dimples are contoured to engage a fuel rod or a thimble tube disposed within the cell. Each spring directly confronts one of the dimples to provide confronting pairs of features that engage the fuel rods or thimble tubes, with each cell including two pairs of confronting features. The ligaments of the springs and dimples extend in a direction generally perpendicular to the direction of coolant flow through the reactor in order to minimize pressure drop.
    Type: Application
    Filed: May 15, 2002
    Publication date: November 20, 2003
    Inventors: Richard P. Broders, Stephen C. Hatfield, Michael L. Martin, Paul F. Joffre, Zeses E. Karoutas, Patrick A. Perrotti
  • Publication number: 20030215049
    Abstract: At regular intervals, the grid strap has formed therein notches for assembly with transverse straps. Between at least some pairs of notches, it has a rod-holding spring comprising two resilient strips cut out from the plane wall of the strap and integral therewith. Each strip extends transversely relative to its strap and is connected to the common portion of the strap at its two ends. In the free state, the strips project towards the inside of the cell concerned and they are interconnected in the middle by a transverse bridge which projects relative to the two strips.
    Type: Application
    Filed: February 5, 2003
    Publication date: November 20, 2003
    Inventors: Roland Mayet, Michel Bonnamour
  • Patent number: 6650723
    Abstract: A double strip mixing grid for nuclear reactor fuel assemblies is disclosed. This grid is fabricated by intersecting at right angles a plurality of double strips, each fabricated by welding two thin sheets together into a single structure with coolant channels. The mixing grid, having the channels, effectively mixes low temperature coolant with high temperature coolant within a fuel assembly, thus improving the thermal efficiency of the fuel assemblies. This mixing grid also effectively prevents the coolant from being partially overheated, thus improving the soundness of nuclear reactors. This mixing grid also has swirling flow blades and/or lateral flow blades to further improve the thermal efficiency of the fuel assembly. This mixing grid elastically supports the fuel rods by the sheets of the double strips, collaterally acting as positioning springs.
    Type: Grant
    Filed: May 22, 2001
    Date of Patent: November 18, 2003
    Assignees: Korea Atomic Energy Research Institute, Korea Electric Power Corporation
    Inventors: Heungseok Kang, Keenam Song, Kyungho Yoon, Hyungkyu Kim, Taehyun Chun, Dongseok Oh, Wangkee In, Yeonho Jung
  • Patent number: 6608881
    Abstract: A duct-type spacer grid for nuclear fuel assemblies is disclosed. In this spacer grid, a plurality of duct-shaped grid elements, individually having an octagonal cell, are closely arranged in parallel and are welded together, thus forming a matrix structure. The grid elements do not pass across the center of the subchannel of the assembly, thus effectively reducing pressure loss. Each of the grid elements is formed as an independent cell, and so they effectively resist against a lateral impact. A plurality of integral type swirl flow vanes, having different heights or same height, axially extend from the top of the grid to be positioned within each subchannel. The swirl flow vanes are bent outwardly, and so they do not contact the fuel rods during an insertion of the fuel rods into the cells. In the spacer grid, the fuel rods are supported within the cells by line contact springs without using any dimple.
    Type: Grant
    Filed: April 3, 2002
    Date of Patent: August 19, 2003
    Assignees: Korea Atomic Energy Research Institute, Korea Electric Power Corporation
    Inventors: Dong-Seok Oh, Tae-Hyun Chun, Wang-Kee In, Kee-Nam Song, Hyung-Kyu Kim, Heung-Seok Kang, Kyung-Ho Yoon, Youn-Ho Jung
  • Patent number: 6606369
    Abstract: An improved grid for use in a fuel assembly of a nuclear reactor includes a plurality of straps connected in a lattice, with a plurality of mixing vanes being disposed on the straps and being arranged such that the hydraulic forces on the mixing vanes generally cancel one another out. The mixing vanes of diagonal quadrants of the grid are generally aligned with diagonally disposed imaginary alignment planes. Each strap includes a plurality of strap members, with each strap member including a spring and a pair of dimples. The spring includes a contoured spring embossment having a greater radius of curvature in a relaxed condition than the radius of a fuel rod. Each dimple includes a similarly configured contoured dimple embossment. The spring embossment is mounted on a pair of legs that extend nonlinearly between a first plate and a second plate of each strap member to increase compliance thereof.
    Type: Grant
    Filed: March 6, 2002
    Date of Patent: August 12, 2003
    Assignee: Westinghouse Electric Company LLC
    Inventors: Levie David Smith, III, Yonghwan Kim, Yu Chung Lee, David Lee Stucker
  • Patent number: 6600800
    Abstract: In a boiling water fuel assembly, some of the fuel rods are shortened. It is necessary to establish a sufficiently high maximum power for transition to boiling. To optimize this power, spacers are at a constant distance at a bottom and are at a shorter distance at a top. The spacers belonging to upper group have turbulence-generating vanes which, however, do not project above the shortened fuel rods.
    Type: Grant
    Filed: June 18, 2001
    Date of Patent: July 29, 2003
    Assignee: Framatome ANP GmbH
    Inventors: Dieter Bender, Otmar Bender, Hans-Joachim Lippert, Walter Übelhack
  • Patent number: 6542567
    Abstract: At regular intervals, the grid strap has formed therein notches for assembly with transverse straps. Between at least some pairs of notches, it has a rod-holding spring comprising two resilient strips cut out from the plane wall of the strap and integral therewith. Each strip extends transversely relative to its strap and is connected to the common portion of the strap at its two ends. In the free state, the strips project towards the inside of the cell concerned and they are interconnected in the middle by a transverse bridge which projects relative to the two strips.
    Type: Grant
    Filed: February 23, 1999
    Date of Patent: April 1, 2003
    Assignee: Framatome
    Inventors: Roland Mayet, Michel Bonnamour
  • Patent number: 6526116
    Abstract: A support grid for laterally maintaining the relative position of elongated fuel elements within a fuel assembly for use within a core of a nuclear reactor. The grid is formed in the shape of a lattice with the intersecting lattice members defining a plurality of cells, most of which respectively support the nuclear fuel elements. The remaining cells support nuclear control rod guide tubes and instrumentation thimbles. The cells supporting the nuclear fuel elements are provided with diagonally positioned springs on two, adjacent walls. The springs support the fuel elements against dimples which protrude from the opposite cell walls. The adjacent, diagonal springs in each fuel element cell are inclined in opposite directions. The walls of the cells supporting the control rod guide tubes are embossed along their height at the locations intermediate the intersection between adjoining walls with a concave notch having a curvature which conforms to the outside surface curvature of the control rod guide tubes.
    Type: Grant
    Filed: July 2, 1997
    Date of Patent: February 25, 2003
    Assignee: Westinghouse Electric Company LLC
    Inventors: Quang M. Nguyen, Yu C. Lee, Edmund E. DeMario, Jeffrey J. Fodi, Darin L. Redinger, Levie D. Smith, III
  • Patent number: 6522710
    Abstract: A spacer for use with a protective grid of a fuel assembly of a nuclear reactor is a generally washer-shaped plate of material having an engagement surface and a retention surface opposite one another. The protective grid is formed of a plurality of straps to define a plurality of fuel rod cells and a plurality of thimble cells, with the straps adjacent the thimble cells being notched to receive the spacer therein. The retention surface of the spacer is disposed against the notches, and the engagement surface of the spacer protrudes outwardly from the protective grid. When the engagement surfaces of the spacers are engaged against a lower nozzle of a fuel assembly of a nuclear reactor, the spacers space the protective grid from the lower nozzle. The spacer is integrally welded with the protective grid in a single arranging and welding operation.
    Type: Grant
    Filed: July 3, 2001
    Date of Patent: February 18, 2003
    Assignee: Westinghouse Electric Company LLC
    Inventors: Michael G. Smith, David A. Dablock, Nathaniel Robinson, Philip L. Hazlett
  • Patent number: 6519309
    Abstract: A spacer grid for PWR assemblies is characterized by curved flow channels between adjacent fuel rods and straight, essentially flat strips connecting opposite side plates of the spacer. The latter strips prevent bowing-out of the side plates during fuel assembly fabrication and during operation in the reactor. Additionally, the spacer grid allows accurate positioning of the fuel rods on a square lattice with a precisely defined pitch, and support of the rods in their spacer cells is such that rod bow will be minimized. The direction of the nozzles on the flow channels has been chosen to promote cross-flow of the coolant through the assembly.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: February 11, 2003
    Assignee: Framatone ANP Inc.
    Inventor: Leonard F. P. Van Swam
  • Publication number: 20030012329
    Abstract: A spacer grid used for placing and supporting fuel rods in nuclear reactor fuel assemblies is disclosed. The spacer grid of this invention has a plurality of grid springs designed to have an optimal shape of their vertical support parts, thus reducing fretting wear of the fuel rods caused by contact of the fuel rods with the grid springs. The grid spring has a vertical support part and a fuel rod support part. The vertical support part includes upper and lower base parts extending downward and upward from the central portions of the top and bottom edges of an opening formed at the central portion of a unit strip, and two bridge parts branched from the upper base part and extending symmetrically downward until they are united at the lower base part. The fuel rod support part includes a conformal support part brought into surface contact with the external surface of a fuel rod.
    Type: Application
    Filed: December 7, 2001
    Publication date: January 16, 2003
    Inventors: Kyung Ho Yoon, Heung Seok Kang, Hyung Kyu Kim, Kee Nam Song, Youn Ho Jung, Tae Hyun Chun, Dong Seok Oh, Wang Kee In, Gyung Jin Park
  • Publication number: 20030007590
    Abstract: A spacer for use with a protective grid of a fuel assembly of a nuclear reactor is a generally washer-shaped plate of material having an engagement surface and a retention surface opposite one another. The protective grid is formed of a plurality of straps to define a plurality of fuel rod cells and a plurality of thimble cells, with the straps adjacent the thimble cells being notched to receive the spacer therein. The retention surface of the spacer is disposed against the notches, and the engagement surface of the spacer protrudes outwardly from the protective grid. When the engagement surfaces of the spacers are engaged against a lower nozzle of a fuel assembly of a nuclear reactor, the spacers space the protective grid from the lower nozzle. The spacer is integrally welded with the protective grid in a single arranging and welding operation.
    Type: Application
    Filed: July 3, 2001
    Publication date: January 9, 2003
    Inventors: Michael G. Smith, David A. Dablock, Nathaniel Robinson, Philip L. Hazlett
  • Patent number: 6498827
    Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving apertures formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.
    Type: Grant
    Filed: November 1, 1999
    Date of Patent: December 24, 2002
    Assignee: Babcock & Wilcox Canada, Ltd.
    Inventor: Richard G. Klarner
  • Patent number: 6473482
    Abstract: A spacer for a fuel assembly of a nuclear reactor includes an elongated spring which is held in a mesh in such a way that there is structural freedom with respect to a selection of a shape of the spring and that little spring material is required. Two lateral rims at a top end of the spring are bent around a center of a fuel element out of the mesh in such a way that they protrude through an assembly opening in the web into an adjacent mesh. The two rims approximately form-lockingly encompass an edge of the assembly opening through the use of a profiled section. A lower end of the spring is also correspondingly held on the web through the use of profiled sections on its two rims, which are bent outward. Two springs protruding into adjacent meshes can then also be fastened in the same assembly opening.
    Type: Grant
    Filed: July 15, 1999
    Date of Patent: October 29, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventor: Alexander Steinke
  • Patent number: 6434209
    Abstract: A Critical Channel Power (CCP) enhancement system is provided for a pressurized fuel-channel-type water-cooled nuclear reactor of the type adapted to be refuelled on-line by the insertion and removal of fuel bundles onto and from of a plurality of said fuel channel assemblies, each of said fuel channel assemblies. A means is provided for interlocking fuel bundles into pairs having their fuel elements aligned, thereby lowering the hydraulic resistance in the fuel channel and enhancing CCP. The means for interlocking prevents misalignment of the paired bundles during their residence time inside the reactor due to continuous rocking and vibration of the fuel bundles exposed to very high coolant mass flow rate and misalignment due to axial separation of bundles impacting upon one another during fuelling operations.
    Type: Grant
    Filed: September 27, 1999
    Date of Patent: August 13, 2002
    Assignee: Atomic Energy of Canada Limited/Energie
    Inventors: Dé C. Groeneveld, John R. Schenk, Rayman Sollychin
  • Patent number: 6421407
    Abstract: A nuclear fuel spacer grid, fabricated by intersecting a plurality of zircaloy or inconel grid strips and used for placing and supporting a plurality of elongated fuel rods within a nuclear fuel assembly, is disclosed. In the spacer grid of this invention, each of the grid strips is not cut away to form separate springs or dimples for supporting the fuel rods, but has an axial slot extending from one end of each strip to a length. The grid strips are intersected at the slots prior to being welded together into a single grid structure at a welding tap formed at an outside end or a middle portion of each of the slots. Each of the grid strips also has a dipper-shaped coolant mixing vane, or a dipper vane, at each of the upper and lower ends thereof. The spacer grid thus maximizes the thermal hydraulic coolant mixing effect within a fuel assembly and stably supports the fuel rods within the assembly while improving the mechanical/structural strength of the assembly, such as a buckling strength.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: July 16, 2002
    Assignees: Korea Atomic Energy Research Institute, Korea Electric Power Corporation
    Inventors: Heung-Seok Kang, Kyung-Ho Yoon, Hyung-Kyu Kim, Kee-Nam Song, Youn-Ho Jung, Tae-Hyun Chun, Dong-Seok Oh, Wang-Kee In
  • Patent number: 6415011
    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.
    Type: Grant
    Filed: September 1, 1999
    Date of Patent: July 2, 2002
    Assignee: Westinghouse Atom AB
    Inventor: Sture Helmersson
  • Patent number: 6400788
    Abstract: A fuel assembly, particularly, a fuel assembly including short-length fuel rods and fuel spacers, is used for a boiling water reactor, which is capable of sufficiently reducing the pressure loss of at least one of the fuel spacers positioned above the upper ends of the short-length fuel rods, irrespective of the arrangement of the short-length fuel rods, and also ensuring the structural strength of the fuel spacer. The fuel assembly includes fuel rods located in a square lattice array, two water rods arranged in a region in which seven of the fuel rods are arrangeable, two fuel spacers for holding the fuel rods and the water rods with mutual intervals kept immovable. Each of the fuel spacers includes cells which are connected to each other and in which the fuel rods are to be inserted, respectively, and a band for surrounding the outermost peripheries of the cells. The short-length fuel rods include four first short-length fuel rods arranged in the outermost peripheral region of the square lattice array.
    Type: Grant
    Filed: February 8, 1999
    Date of Patent: June 4, 2002
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Atsuya Hirano, Satoshi Kanno, Makoto Irube, Hideki Kurosaki, Yasuhiro Aizawa, Takashi Fukumoto
  • Patent number: 6393087
    Abstract: A duct-type spacer grid for nuclear fuel assemblies is disclosed. In this spacer grid, a plurality of duct-shaped grid elements, individually having an octagonal cell, are closely arranged in parallel and are welded together, thus forming a matrix structure. The grid elements do not pass across the center of the subchannel of the assembly, thus effectively reducing pressure loss. Each of the grid elements is formed as an independent cell, and so they effectively resist against a lateral impact. A plurality of integral type swirl flow vanes, having different heights or same height, axially extend from the top of the grid to be positioned within each subchannel. The swirl flow vanes are bent outwardly, and so they do not contact the fuel rods during an insertion of the fuel rods into the cells. In the spacer grid, the fuel rods are supported within the cells by line contact springs without using any dimple.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: May 21, 2002
    Assignees: Korea Atomic Energy Research Institute, Korea Electric Power Corporation
    Inventors: Dong-Seok Oh, Tae-Hyun Chun, Wang-Kee In, Kee-Nam Song, Hyung-Kyu Kim, Heung-Seok Kang, Kyung-Ho Yoon, Youn-Ho Jung
  • Patent number: 6385271
    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).
    Type: Grant
    Filed: February 10, 1999
    Date of Patent: May 7, 2002
    Assignee: Westinghouse Atom AB
    Inventor: Olov Nylund
  • Patent number: 6332012
    Abstract: A nuclear fuel assembly grid has a plurality of mutually interleaved straps forming an array of fuel rod receiving cells. Each strap is formed with regularly distributed slots for interleaving with other straps of the grid. The strap has dimples located between some at least of the slots for maintaining fuel rods in the cells. An uptstream portion of the plate extending in transverse relation to a coolant flow direction has a double sided concave chamfer.
    Type: Grant
    Filed: July 10, 1998
    Date of Patent: December 18, 2001
    Assignees: Framatome, Compagnie Generale des Matieres Nucleaires
    Inventor: Bernard Petit
  • Patent number: 6320925
    Abstract: A spacer of a fuel assembly having intersecting webs undergoes reduced longitudinal expansion as a result of corrosion during an operating period. The webs have intersection locations at which assembly gaps are provided. The assembly gaps have widths which correspond essentially, at most over a fraction of their total length, to the wall thickness of an intersecting web, but are wider in a remaining region. Since corrosion layers growing from an edge of an assembly gap toward the intersecting web cannot touch the web, no solid pressure, which could lead to longitudinal expansion, builds up.
    Type: Grant
    Filed: January 27, 1999
    Date of Patent: November 20, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Reiner Manzel, Werner Jahreiss, Norbert Schmidt, Josef Steven, Peter Dewes, Friedrich Garzarolli, Erhard Ortlieb, Franz-Josef Bökers, Matthias Rudolph
  • Publication number: 20010040936
    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).
    Type: Application
    Filed: February 10, 1999
    Publication date: November 15, 2001
    Inventor: OLOV NYLUND