With Coolant Flow Path Deflecting Means Patents (Class 376/439)
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Patent number: 5180548Abstract: A mixing grid for use in a pressurized reactor comprises at least two sets of crossed fixed together at their cross-points, delimiting cells, some for receiving fuel rods and the others for receiving guide tubes, the plates being provided with coolant stirring fins extending the plates downstream and disposed to deflect the coolant transversely to its general flow direction, each plate being provided with abutment means projecting inwardly from each of the faces of the cells for receiving fuel rods, thereby delimiting a passage that is larger than the size of the rods but small enough to prevent a rod contained in the cell coming into contact with the fins. In each wall the abutment means comprise two portions of plate that are cut out and deformed into a scoop-shape, and that are offset relative to each other in the coolant flow direction, with the scoops projecting in opposite directions and tending to cause coolant to pass from one cell to another.Type: GrantFiled: July 24, 1991Date of Patent: January 19, 1993Assignees: Framatome, Compagnie Generale Des Matieres NucleairesInventor: Michel Verdier
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Patent number: 5178825Abstract: In a nuclear fuel bundle for a boiling water reactor, the prior art suggested concept of tapered fuel rods forming the bundle array is disclosed in a practical design including a fuel bundle and an improved associated spacer utilized in the upper two phase region of the fuel bundle. A tapered fuel rod is utilized having a large diameter bottom tube for holding corresponding large diameter fuel pellets at the fuel rod bottom, a smaller diameter top tube for holding correspondingly smaller diameter pellets at the top of the fuel rod, and a bell reducer situated between the large diameter lower fuel tube and the smaller diameter upper fuel tube. This bell reducer tapers from the large outside diameter of the lower fuel tube and the smaller outside fuel diameter of the upper fuel tube and forms a smooth transition between the large and small diameter sections of the fuel rod. An improved fuel rod spacer is disclosed for use with the upper and smaller tube portions of the fuel rods.Type: GrantFiled: November 29, 1991Date of Patent: January 12, 1993Assignee: General Electric CompanyInventor: Eric B. Johansson
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Patent number: 5174949Abstract: A fuel bundle and fuel bundle assembly sequence utilizing a peanut sectioned large water rod is shown locking spacers into place along the axial length of the water rod. In a first embodiment, clearance is defined relative to tabs welded on the large water rod so that spacer assembly to the water rods can occur. In a second and preferred embodiment, spacers are individually equipped with springs locking into complimentary apertures in the peanut sectioned water rod. In both embodiments, the spacers are threaded onto the peanut sectioned water rod and locked into alignment for the receipt of the fuel rods. An improved suspension of the water rod relative to the lower tie plate is disclosed in which a transition piece connects the large water rod to a flexible rod which is threaded at its lower end. This rod is screwed into a threaded aperture in the lower tie plate.Type: GrantFiled: May 17, 1991Date of Patent: December 29, 1992Assignee: General Electric CompanyInventor: Eric B. Johansson
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Patent number: 5167911Abstract: A fuel assembly comprises a plurality of fuel rods which contain nuclear fuel material inside, a lower tie plate which holds the lower end of the fuel rods and has a path inside to lead coolant between the fuel rods, and a channel box which encloses a bundle of the fuel rods. An orifice, in which a plurality of round rods are arranged to cross the coolant flow path, is installed in a through hole at a side wall of the lower tie plate by connecting to the side wall. Orifice coefficient of the orifice becomes large at small flow rate of coolant which supplied to the fuel assembly, and becomes small at large flow rate of coolant. By using the fuel assembly described above, void fraction in a gap region between fuel assemblies can be altered during beginning and end of an operation cycle of the nuclear reactor.Type: GrantFiled: March 14, 1991Date of Patent: December 1, 1992Assignee: Hitachi, Ltd.Inventors: Koji Fujimura, Yasunori Bessho, Yoshihiko Ishii, Sadao Uchikawa, Yuichiro Yoshimoto, Junjiro Nakajima
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Patent number: 5164155Abstract: A fuel bundle having spacers optimally deployed is disclosed wherein the distance between the spacers varies along the length of the fuel bundle. The fuel bundle has a dense fuel rod array (preferably in the range of 10.times.10). It includes at least one part length rod extending from the lower tie plate toward but not to the upper tie plate, which part length rod terminates at a spacer and defines under the upper tie plate overlying the end of the spacer a vent volume for the preferential venting of vapor moderator (steam) from the fuel bundle. A vertical spatial distribution of the spacers is disclosed in which the bottom spacers in the single phase region of the fuel bundle are relatively closely vertically spaced and the upper spacers are relatively more distantly vertically spaced one from another.Type: GrantFiled: May 6, 1991Date of Patent: November 17, 1992Assignee: General Electric CompanyInventors: Richard A. Wolters, Anthony P. Reese, Thomas G. Dunlap
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Patent number: 5143691Abstract: A fuel assembly for a boiling water reactor includes an elongated case having an interior and inner surfaces. A base part has inlet openings discharging into the interior of the case for coolant flowing in a given flow direction and a head part has outlet openings leading out of the interior of the case for the coolant flowing in the given flow direction. Mutually parallel fuel rods containing nuclear fuel are disposed in the case between the base and head parts. The inner surfaces of the case have a profile with a rectilinear alignment as seen in the given flow direction and flow trippers extending transversely to the alignment in the form of bulges protruding inward in the given flow direction. Each of the bulges has a sloped surface facing toward the coolant with an impact surface substantially perpendicular to the given flow direction.Type: GrantFiled: November 28, 1990Date of Patent: September 1, 1992Assignee: Siemens AktiengesellschaftInventors: Hans-Joachim Lippert, Wendelin Kraemer
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Patent number: 5139736Abstract: A strip (16) for an eggcrate-type nuclear fuel assembly grid (10), in which the fuel rod support springs (30,36) are formed by beams (75,77) and a connecting arch (78). More particularly, the strip has a substantially flat body (56), upper and lower edges (84,86) defining the strip vertical height, and opposed side edges (80) defining the length of the body. The fuel rod support structure (30) projects transversely from the body and comprises a plurality of spring members spaced apart in the longitudinal direction along the body, each spring member having a pedestal portion (75,77) resiliently supported by the body and a contact portion (78) integrally formed on and projecting from the pedestal portion. The pedestal portion preferably includes a beam integrally constrained at both ends by the body. By integrally fixing the ends, the spring member can be considerably smaller and produce the same force for a given deflection as a conventional grid.Type: GrantFiled: April 3, 1991Date of Patent: August 18, 1992Assignee: Combustion Engineering, Inc.Inventor: William J. Bryan
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Patent number: 5128098Abstract: A fuel assembly comprises a plurality of fuel rods, a lower tie plate for supporting lower ends of the fuel rods, and a channel box surrounding a bundle of the fuel rods and the circumference of the lower tie plate to thereby define a cooling water leak passage between the lower tie plate and the channel box. The fuel assembly includes a venturi provided in the lower tie plate for generating a force tending to attract the channel box toward the lower tie plate under the action of a leak stream of the cooling water passing through the cooling water leak passage. The fuel assembly also includes an arrangement provided in the lower tie plate for suppressing vibrations of the channel box caused upon an influence of the venturi.Type: GrantFiled: January 9, 1991Date of Patent: July 7, 1992Assignee: Hitachi, Ltd.Inventors: Shozo Nakamura, Tadashi Mizuno, Junjiro Nakajima, Yoshihiko Yanagi, Hajime Umehara, Tetsuo Yasuda, Akira Maru, Junichi Yamashita, Yuichiro Yoshimoto, Tatsuo Hayashi
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Patent number: 5112571Abstract: In a fuel assembly having fuel rods inserted into regularly arranged cells of a fuel spacer which keeps the fuel rods correctly spaced from one another and has spacer elements disposed in a plurality of stages in the longitudinal direction of the fuel rods, the fuel spacer comprises vanes formed on the cells in such a manner that each vane is bent from a cut formed in a part of the side wall of the cell. The vanes obliquely project into the corresponding spaces between adjacent fuel rods and allow a coolant flowing through the spaces and forming two-phase flows to generate swirling flows toward the fuel rods. The fuel spacer may alternatively comprise either thin-walled cylinders having built-in vanes or spiral vanes, which are fixed to the spacer that has not been subjected to any direct machining. Also disclosed is a fuel assembly provided with any of the above-described fuel spacers.Type: GrantFiled: April 17, 1990Date of Patent: May 12, 1992Assignee: Hitachi, Ltd.Inventors: Akihito Orii, Osamu Yokomizo, Yasuhiro Masuhara, Koji Nishida, Shigeto Murata, Shin-ichi Kashiwai, Kotaro Inoue, Yuichiro Yoshimoto
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Patent number: 5110539Abstract: A method and apparatus for assembling an egg-crate type grid (10) by orthogonally interengaging slots (30,32) cut transversely into one longitudinal edge of each of a plurality of metal strips (12,14). A first plurality of strips (14) is supported on their lower unslotted edges in north-south orientation so that the strips are uniformly spaced apart in parallel in the east-west direction with all the slots (32) oriented upwardly on the upper edge. The slotted upper edges (26) of adjacent north-south strips are then spread farther apart in the east west direction while maintaining the lower edges (28) at said uniform spacing. The lower, slotted edges (24) of a second plurality of east-west oriented strips are interengaged with the north-south strips while the selected portions of the upper edges of the north-south strips are spread. The upper edges of the first plurality of strips are then returned to the unspread orientation.Type: GrantFiled: December 7, 1990Date of Patent: May 5, 1992Assignee: Combustion Engineering, Inc.Inventors: Patrick A. Perrotti, Zeses E. Karoutas
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Patent number: 5106575Abstract: A nuclear fuel assembly has a plurality of fuel rods and a lower tie plate supporting their lower ends. Coolant apertures extending through the lower tie plate. A channel box surrounds the fuel rods and receives the lower tie plate, to confine the coolant. To restrict leakage of coolant between the tie plate and the channel box, the coolant apertures include, adjacent the periphery of the lower tie plate, a plurality of peripheral apertures which are located at least partly outside the outermost fuel rods. The peripheral apertures each provide a coolant velocity peak located further from the axial center line of the tie plate than the axial center lines of the closest neighboring fuel rods. The invention also provides venturis in the leakage path between the channel box and the tie plate, to restrict deformation of the tie plate.Type: GrantFiled: January 12, 1990Date of Patent: April 21, 1992Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.Inventors: Shozo Nakamura, Tadashi Mizuno, Tetsuo Yasuda, Akira Maru, Yoshishige Kawada, Yoshihiko Yanagi, Hiromasa Hirakawa, Junjiro Nakajima, Yasuhiro Aizawa, Yorihide Segawa
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Patent number: 5100611Abstract: A fuel assembly for a light-water nuclear reactor contains a plurality of vertical fuel rods which are arranged, mutually spaced from each other in the lateral direction, between a bottom tie plate and a top tie plate. The bottom tie plate is provided with through-holes for conducting water through the bottom tie plate and into the spaces between the fuel rods. The through-holes in the bottom tie plate have parts, the centre lines of which are displaced in relation to each other or make an angle with each other.Type: GrantFiled: December 10, 1990Date of Patent: March 31, 1992Assignee: Abb Atom AbInventor: Olov Nylund
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Patent number: 5096660Abstract: A fuel assembly in the form of an elongated channel having several corners is connected to a coolant intended to flow through the channel. A bundle of similarly elongated fuel rods, retained by a plurality of spacers, is arranged in the channel, and arranged in the upper part of the fuel assembly, at least between a pair of spacers, is a sleeve formed of a sheet around the bundle. The sleeve has an external shape which conforms closely to the walls of the fuel assembly and is perforated by a large number of openings, the total surface of which is at least as large as the sheet surface remaining on one side of the sleeve.Type: GrantFiled: October 31, 1990Date of Patent: March 17, 1992Assignee: ABB Atom ABInventors: Olof Hembjer, Ragnar Mansson, Olov Nylund
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Patent number: 5089220Abstract: The invention relates to a fuel assembly in the form of an elongated channel having several corners. The channel is connected to a coolant intended to flow through the channel. A bundle of similarly elongated fuel rods, retained by a plurality of spacers (8), is arranged in the channel. The spacer (8) has an outer frame which is provided all around with a plurality of windows (10). According to the invention, deflection fins (9) are placed in said window and are so directed that cooling water flowing along the wall of the fuel assembly is diverted in a direction towards the center of the channel to improve the cooling for those fuel rods which are located in this region.Type: GrantFiled: October 31, 1990Date of Patent: February 18, 1992Assignee: ABB Atom ABInventor: Olov Nylund
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Patent number: 5084237Abstract: A grid spacer for a nuclear reactor fuel assembly is formed of two superposed combs. Each comb has a base strip which extends the width of the assembly. To it are attached parallel grid strips which are free at their other ends. The grid strips are perpendicular to the base strip and are formed for spring engagement with the fuel rods of the assembly. The combs can be inserted from the sides of the assembly, so that an additional or substitute spacer can be added to the assembly without disassembling the latter.Type: GrantFiled: September 1, 1989Date of Patent: January 28, 1992Assignee: Advanced Nuclear Fuels CorporationInventors: John F. Patterson, Richard H. Ewing
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Patent number: 5080858Abstract: The invention relates to a fuel assembly in the form of an elongated channel having several corners. The channel is connected to a coolant intended to flow through the channel. A bundle of similarly elongated fuel rods, retained by a plurality of spacers (8), is arranged in the channel. The spacer (8) comprises a number of cells surrounded by an outer frame which is formed from a band placed on edge. According to the invention, the band is extended on the upstream side of the spacer (8) by a skirt (12), in which openings (13) are provided. In certain of these openings deflection fins (14) have been arranged in order to deflect coolant, flowing along the assembly wall (6), in a direction towards the center of the respective spacer (8).Type: GrantFiled: October 31, 1990Date of Patent: January 14, 1992Assignee: ABB Atom ABInventor: Olov Nylund
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Patent number: 5078961Abstract: A spacer with a spring construction for the fuel bundle having matrix of parallel side by side fuel rods supported within a fuel channel between a supporting lower tie plate and holding upper tie plate is illustrated. The spacers each have a corresponding matrix of individual ferrules each surrounding the discrete fuel rods to be spaced within the matrix of fuel rods at any given elevation within the fuel bundle. Each of the individual ferrules surrounding the individual fuel rods are provided with stops against which the fuel rods are biased to ensure the required side-by-side spacing. Each ferrules must have at least one spring for forcing the fuel rods against the stops of its spacer ferrules to enable the spacer to assure required side-by-side alignment of the fuel rod. The springs are provided with a continuously looping main body having protruding tabs on opposite sides of the springs.Type: GrantFiled: December 6, 1990Date of Patent: January 7, 1992Assignee: General Electric CompanyInventors: Eric B. Johansson, Harold B. King
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Patent number: 5030412Abstract: A debris screen for a fuel assembly for a reactor to which coolant fluid is supplied comprises a substantially planar plate member having an array of coollant openings extending through the plate member dimensioned to trap at least a portion of debris particles carried by the coolant; and a skirt member enclosing the periphery of the plate member; each of the coolant flow openings having a coolant entry region at a lower surface, a coolant exit region at an upper surface and a coolant flow path extending between the entry and exit regions, the flow path including an intermediate segment laterally offset from the entry and exit regions to cause coolant to change direction of flow in the intermediate segment and thereby prevent at least a portion of the debris particles from passing through the plate members.Type: GrantFiled: May 4, 1990Date of Patent: July 9, 1991Assignee: Advanced Nuclear Fuels CorporationInventors: Jack Yates, Richard H. Ewing, John F. Patterson
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Patent number: 5002725Abstract: A nuclear reactor fuel assembly includes an elongated fuel channel having opposite channel sides. Fuel rods containing nuclear fuel are mutually spaced apart in the fuel channel and parallel to the longitudinal direction of the fuel channel. A water tube inside the fuel channel has an outer surface and is parallel to the fuel rods. The water tube has a lower end with an inlet opening and an upper end with an outlet opening for liquid water. A longitudinal rib inside the fuel channel is secured to and interconnects two of the opposite channel sides and is spaced apart from the others of the channel sides. The longitudinal rib is longitudinally divided into two partial ribs each being secured to the outer surface of the water tube.Type: GrantFiled: July 6, 1990Date of Patent: March 26, 1991Assignee: Siemens AktiengesellschaftInventors: Hans Lettau, Gunther Lill, Hans-Joachim Lippert, Roland Rink
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Patent number: 4999153Abstract: A combination of flow trippers with spacer deflectors in the two phase steam/water region of a fuel bundle in a boiling water reactor is disclosed. Spacers with deflectors are placed immediately above the flow trippers. The flow trippers are located on either an inside channel wall surrounding the fuel bundle or the outside of water chambers within the fuel bundle. Additional flow trippers may be located adjacent to the spacers, above the flow trippers that are below the spacers. The spacers are provided with deflector skirts overlying the flow trippers. In operation of the fuel bundle, excess water flows in the two phase region in a film on the unheated inside walls of the fuel channel or the outside walls of the water chambers. The film flow is perturbed by the flow trippers and is deflected toward the fuel rods. The overlying deflector skirts or tabs on the spacers further deflect the liquid toward the fuel rods to improve cooling and to increase the power generation capability of the fuel bundle.Type: GrantFiled: March 21, 1990Date of Patent: March 12, 1991Assignee: General Electric CompanyInventors: Eric B. Johansson, Robert B. Elkins, Russell L. Crowther, Bruce Matzner
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Patent number: 4990304Abstract: A nuclear fuel assembly has mechanical elements which constrain the flux thimble tube within the instrumentation tube to maintain physical contact with the interior surface of the instrumentation tube at a plurality of points staggered on a single-diametral plane and spaced substantially throughout the length of the instrumentation tube. The staggered mechanical elements induce a controlled elastic sinuous deflection of the inner thimble tube. The mechanical elements can take several different forms, for example, dimples or cantilevered spring fingers formed in the wall of the instrumentation tube and projecting radially inwardly therefrom.Type: GrantFiled: January 27, 1989Date of Patent: February 5, 1991Assignee: Westinghouse Electric Corp.Inventor: John A. Rylatt
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Patent number: 4980121Abstract: A nuclear fuel assembly having an array of longitudinally extending fuel rods and axially spaced transverse grids with cells receiving the fuel rods therethrough employs anti-fretting protective devices for protecting lower end portions of tubular claddings of the fuel rods from damage-inducing contact with debris entrained in upward flow of coolant through the fuel assembly. Each device is in the form of a hollow sleeve disposed about and extending coextensive with the lower end portion of one fuel rod cladding. The sleeve has an upper portion which extends through one grid cell between lower and upper ends thereof, and a lower portion which extends below the grid cell from the lower end thereof to a bottom end of the fuel rod cladding spaced below the grid cell lower end.Type: GrantFiled: July 28, 1989Date of Patent: December 25, 1990Assignee: Westinghouse Electric Corp.Inventors: Elwyn Roberts, Warren L. Mauterer, Harry M. Ferrari, Robert N. Stanutz
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Patent number: 4970047Abstract: A fuel assembly for a nuclear reactor comprises a fuel bundle in which a number of fuel rods are regularly arranged and a channel box surrounding the outer periphery of the fuel bundle. The interior of the channel box is designed so that the inner cross sectional area of the channel box increases from the upstream side of the coolant flow towards the downstream side thereof, for example, by stepwisely shaving the inner surface of the channel box. The corner portions of the channel box may be chamfered to improve the stress due to the inner pressure.Type: GrantFiled: October 13, 1988Date of Patent: November 13, 1990Assignee: Kabushiki Kaisha ToshibaInventors: Makoto Ueda, Toru Mitsutake, Koichi Sakurada, Koji Hiraiwa, Yasuhiro Hattori, Mamoru Nagano, Hironori Echigoya
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Patent number: 4970048Abstract: A grid for a nuclear fuel assembly comprises a common frame having an axis and a plurality of beds of plates distributed along the axis. Each bed has a plurality of plates which are mutually parallel and are directed transversely to the plates of the adjacent beds. All plates are secured to the common frame. The plates having a same direction are distributed between a plurality of said beds interleaved with other ones of said beds consisting of plates having another direction, and the plates of the beds placed in an upstream portion of the grid have fins oriented so as to deflect coolant inwardly whereas the plates placed in a downstream portion of the grid have fins oriented so as to deflect the flow coolant outwardly.Type: GrantFiled: June 29, 1989Date of Patent: November 13, 1990Assignees: Framatome, Compagnie Generale des Matieres NucleairesInventor: Jean Noailly
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Patent number: 4951299Abstract: An intermediate mixing grid for nuclear reactor fuel assemblies is made without the usual perimeter strip. The ends of the grid members are formed so that they hold the fuel rods at the edges of the assembly in place.Type: GrantFiled: January 11, 1989Date of Patent: August 21, 1990Assignee: Advanced Nuclear Fuels CorporationInventors: John F. Patterson, Richard H. Ewing, Jack Yates
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Patent number: 4933138Abstract: The spacer-grid comprises at least one single-piece plate (1) through which extend a group of openings (2) at least a part of which constitutes an even network of passages (2) for the fuel rods and the guide tubes of the fuel assembly. The spacer-grid may be formed by one single-piece plate (1) of great thickness or by the association of a plurality of parallel single-piece plates interconnected by an outer girdle element.Type: GrantFiled: June 9, 1988Date of Patent: June 12, 1990Assignees: Framatome, CogemaInventors: Bruno Mouesca, Jean-Pierre Denizou
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Patent number: 4913875Abstract: A spacer assembly for imparting a swirl to a passing steam water mixture within a fuel channel of a boiling water reactor is disclosed. The spacer assembly is placed at periodic intervals along the inside of a square cross sectioned fuel channel so as to separate the fuel containing rods from each other and the fuel channel sides. Each discrete spacer element is constructed of a matrix of helically twisted sheet metal spacing elements for the serendipitous purposes of providing separation of the steam and water, with water being deposited on the fuel rods surfaces. Each helical element is a twisted planar metallic member and includes a rotation of the metal surfaces in the order of 450.degree. over a typical two inches of length. For each 90.degree. interval of rotation from the top and bottom of each helical element, paired lattice connections are provided for attachment to adjoining elements. Intermediate of the lattice connectors at 45.degree.Type: GrantFiled: March 14, 1989Date of Patent: April 3, 1990Assignee: General Electric CompanyInventors: Eric B. Johansson, Louis C. Bulger
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Patent number: 4913876Abstract: A nuclear reactor fuel assembly includes an elongated fuel assembly box. Fuel rods containing nuclear fuel are mutually spaced apart in the fuel assembly box and parallel to the longitudinal direction of the fuel assembly box. A water tube inside the fuel assembly box is parallel to the fuel rods. The water tube has a lower end with an inlet opening and an upper end with an outlet opening for liquid water. A shield is fastened inside the water tube and spaced apart from both of the ends of the water tube. A flowthrough opening is formed in the shield or between the shield and the water tube for the liquid water.Type: GrantFiled: April 6, 1988Date of Patent: April 3, 1990Assignee: Siemens AktiengesellschaftInventors: Hans Lettau, Gerhard Preusche, Guenther Lill
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Patent number: 4889684Abstract: In a nuclear boiling water reactor, an improved lower tie-plate and fuel channel interface for a boiling water reactor fuel bundle is disclosed. The fuel bundle has a lower tie-plate for supporting fuel rods and permitting the introduction of fluid interior of the fuel bundle. An upper tie-plate maintains the lower tie-plate supported rods in side-by-side relation and has apertures for discharging a mixture of water and steam. The fuel rods extend between the tie-plates for the generation of steam with some of the fuel rods forming a threaded connection fastening the tie-plates together. A polygon sectioned channel, preferably square, surrounds the tie-plates and fuel rods for the confining of fluid flow between the tie-plates interior of the bundle. The interface of the channel as it surrounds the lower tie-plate is reconfigured.Type: GrantFiled: August 1, 1988Date of Patent: December 26, 1989Assignee: General Electric CompanyInventor: Eric B. Johansson
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Patent number: 4879090Abstract: Integral vanes 4 with optimized size, shape and bend angles maximize coolant mixing and fuel rod 12 heat transfer downstream. Recessed weld nuggets 5 with no vane cutout are optimized for size, strength and corrosion resistance. Staggered arches 20',22' and springs 20,22 minimize turbulence and reduce grid pressure drop and promote coolant mixing. Crowned arches 20',22' and springs 20,22 decrease scoring of fuel rods 12 and are sized to minimize turbulence and pressure drop. Minimum cutouts in unslotted section of grid strip 46,46' give 15-20% strength increase. Intermediate weld and tapered end slots 48 give 15% strength increase. Ribbed and round dimple stiffeners 38,39 on outer strips increase buckling resistance, reduce handling damage and spreads accidental loading. Outer strips 32 are optimized for strength, handling, turbulence generation and pressure drop. They also divert enough flow to interior of fuel assembly to match thermal power distribution and eliminate fuel rod corrosion concerns.Type: GrantFiled: August 24, 1987Date of Patent: November 7, 1989Assignee: Combustion Engineering, Inc.Inventors: Patrick A. Perrotti, Paul F. Joffre, Zeses E. Karoutas, Lawrence V. Corsetti, William J. Bryan, Stephen C. Hatfield
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Patent number: 4876063Abstract: In a nuclear fuel bundle having a lower tie-plate, an upper tie-plate and a surrounding channel therebetween, an improved water rod is disclosed for preferable use when fuel rods held between the tie-plates are placed in a 9 by 9 array. Typically, seven fuel rods are omitted centrally of the 9 by 9 array with the middle or fifth row having three rods removed and paired rods being removed in the 4th and 6th row with displacement of the removed pair towards opposite corners. Into the volume created by the removal rods, there are placed two "D" sectioned rods, the "D" rods each being round in cross-section except for a truncating chord, this truncating chord defining the straight back of each "D". In the preferred embodiment one of the "D" water rods is provided with spacer tabs for maintaining spacers separating the fuel rod at their correct elevations. This rod is inserted with an alignment that permits the tabs to pass through the spacers.Type: GrantFiled: March 17, 1988Date of Patent: October 24, 1989Assignee: General Electric CompanyInventor: Eric B. Johansson
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Patent number: 4871510Abstract: A fuel assembly of the present invention comprises fuel rods which are arranged in 9 rows and 9 columns (9.times.9) in a channel box. The channel box has a width L between outer walls thereof and a width D between inner walls thereof, both of which satisfy the following equation:0.12.ltoreq.(P-L)/Dwherein P denotes the fuel assembly pitch in a reactor core. A sufficient cold shutdown margin for a reactor core can be secured by determining the widths L and D so as to satisfy the above-described equation, even if the average enrichment of the fuel assembly is increased to 4 wt % or more.Type: GrantFiled: April 7, 1988Date of Patent: October 3, 1989Assignee: Hitachi, Ltd.Inventors: Motoo Aoyama, Renzo Takeda
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Patent number: 4849161Abstract: A fuel assembly for nuclear reactors which comprises the usual upper and lower tie plates and fuel rods extending between them is made debris-resistant by providing a grid spacer in contact, or very nearly so, with the lower tie plate and so positioned as to subdivide the usual openings in the lower tie plate which are provided for the passage of cooling water. This causes debris to be trapped in the openings of the lower tie plate, and keeps it from contacting the fueled portion of the assembly.Type: GrantFiled: November 24, 1987Date of Patent: July 18, 1989Assignee: Advanced Nuclear Fuels Corp.Inventors: Charles A. Brown, Rolf Holzer, John F. Patterson
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Patent number: 4844860Abstract: A fuel element support grid for supporting a plurality of nuclear fuel elements intermediate their ends has at least some of the pairs of intersecting and slottedly interlocked strips including pairs of intersecting integral fluid flow directing vanes along at least one adjacent edge of each of the strips of the pair. Welds attach the pair of vanes to each other thereby providing welded attachment of the strips. The welds may be at the intersection of the vanes remote from their areas of integral attachment to their respective strips or they may be adjacent to their areas of integral attachment to their respective strips. The strips may be bent to provide the strip function and the arch function within the same stream engaging profile as the strip alone presents.Type: GrantFiled: May 11, 1987Date of Patent: July 4, 1989Assignee: Combustion Engineering, Inc.Inventor: Stephen C. Hatfield
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Patent number: 4844861Abstract: A fuel assembly for nuclear reactors comprising a skeleton having two end pieces connected together by elongate elements and several grids spaced apart along the guide tubes and forming cells for holding a bundle of fuel elements in position at the nodes of a regular lattice. The grids comprise median grids adapted for resisting lateral shocks and having fins for creating turbulences in the flow of the coolant along the assembly, bottom grids without fins and ensuring the cross bracing of the elements and top grids with fins and ensuring cross bracing of the elements, the top and bottom grids imposing on the coolant a pressure loss lower than the median grids.Type: GrantFiled: December 6, 1985Date of Patent: July 4, 1989Assignee: FragemaInventor: Joseph Leclercq
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Patent number: 4832901Abstract: A method for reparing bent mixing vanes in a nuclear reactor fuel assembly is described, including the steps of introducing an apparatus having movable blades below a grid with a mixing vane; opening the blades; withdrawing the apparatus so that a blade abuts and straightens the bent mixing vane; closing the blades; and fully extracting the apparatus from the fuel cell.Type: GrantFiled: January 21, 1988Date of Patent: May 23, 1989Assignee: Westinghouse Electric Corp.Inventor: George F. Dailey
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Patent number: 4827063Abstract: A nuclear reactor fuel assembly includes mutually parallel fuel rods and guide tubes for control rods. Two lattice-like spacers have mesh openings formed therein. One of the fuel rods or one of the guide tubes is guided and secured in each of the mesh openings. An additional lattice is secured at least to one of the guide tubes between the two spacers as seen in the longitudinal direction of the fuel rods and the guide tubes. The additional lattice has mesh openings formed therein defining sides of the mesh openings and a smooth and flat surface of the additional lattice in the mesh openings. Turbulence-promoting vanes protrude beyond the sides of the mesh openings formed in the additional lattice. One of the fuel rods is guided with play or one of the guide tubes is guided through each of the mesh openings formed in the additional lattice. Brackets grip the additional lattice between at least one of the fuel rods or the guide tubes at the outside of the fuel assembly.Type: GrantFiled: September 24, 1987Date of Patent: May 2, 1989Assignee: Siemens AktiengesellschaftInventors: Franz-Josef Bokers, Alexander Steinke
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Patent number: 4818479Abstract: The invention relates to a nuclear reactor spacer grid member for use in a liquid cooled nuclear reactor and to a ductless core component employing a plurality of these spacer grid members. The spacer grid member is of the egg-shell type and is constructed so that the walls of the cell members of the grid member are formed of a single thickness of metal to avoid tolerance problems. Within each cell member is a hydraulic spring which laterally constrains the nuclear material bearing rod which passes through each cell member against a hardstop in response to coolant flow through the cell member. This hydraulic spring is also suitable for use in a water cooled nuclear reactor. A core component constructed of, among other components, a plurality of these spacer grid members, avoids the use of a full length duct by providing spacer sleeves about the sodium tubes passing through the spacer grid members at locations between the grid members, thereby maintaining a predetermined space between adjacent grid members.Type: GrantFiled: October 4, 1985Date of Patent: April 4, 1989Assignee: The United States of America as represented by the United States Department of EnergyInventors: David W. Christiansen, Richard A. Karnesky
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Patent number: 4804516Abstract: Fuel assembly for the core of a nuclear reactor comprising spacing grids situated in the upper part of the assembly arranged at smaller intervals from one another than the grids situated in the lower part of the assembly. The upper grids ensure a more intense mixing of the coolant downstream than the lower grids, so as to reduce corrosion at the upper part and the temperature difference between the top of the sheath and the coolant.Type: GrantFiled: May 20, 1987Date of Patent: February 14, 1989Assignees: Framatome, Compagnie Generale Des Matieres NucleairesInventors: Joel Thomazet, Andre Kolmayer
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Patent number: 4781884Abstract: A debris catching strainer grid for capturing and retaining deleterious debris carried by reactor coolant before it enters the active region of a fuel assembly and creates fuel rod cladding damage has a plurality of fuel end cap compartments defined by pairs of first and second intersecting and slottedly interlocked grid-forming strips attached to a perimeter member and to each other. The end cap compartments defined by strips including vertical rows of integral leaves on opposite sides of the strip or by pairs of adjacent integral leaves intermediate their intersections. In the latter case, each leaf of the pair of leaves is the mirror image of the other leaf of the pair with an asymmetric shape with the greatest distance of projection out of the plane of the strip remote from the midpoint of the strips between their intersections.Type: GrantFiled: March 2, 1987Date of Patent: November 1, 1988Assignee: Combustion Engineering, Inc.Inventor: Andrew J. Anthony
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Patent number: 4775509Abstract: A grid for use in a PWR assembly includes a peripheral girdle and at least two sets of parallel plates. The plates of one set are at an angle with respect to those of the other set so that the sets defined cells for the fuel rods. The parallel plates are distributed in at least two beds spaced apart in the longitudinal direction of the assembly. In a fuel assembly having a triangular array of fuel rods, three successive beds of mutually parallel plates are provided.Type: GrantFiled: February 24, 1987Date of Patent: October 4, 1988Assignees: Framatome, Compagnie Generale des Matieres NucleairesInventors: Jean Noailly, Jean-Pierre Denizou
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Patent number: 4775510Abstract: A hollow flow deflector (10) for use in a nuclear reactor fuel assembly having spaced grids of orthogonal strips (16, 18) mounted for defining square matrices of aligned and supported cylindrical fuel elements (12, 14). The deflector has a central cylindrical opening (20), an upstream end portion (22), a downstream end portion (24) and an intermediate transition portion (26) joining the end portions. The hollow flow deflector (10) has a plurality of concave flow channels (30) regularly spaced about the periphery of the body in its downstream end portion. The flow channels (30) have their inlet portion defined in the transition portion (26) of the body (10).Type: GrantFiled: December 22, 1986Date of Patent: October 4, 1988Assignee: Combustion Engineering, Inc.Inventor: William J. Bryan
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Patent number: 4765949Abstract: A spacing grid for a nuclear fuel assembly, particularly a water cooled assembly, includes two spaced sets of plates. Each set is formed of plates parallel to each other and fixed at their ends to a polygonal belt in the form of a strip having fins along one longitudinal edge at least. Each corner of the belt is free of openings. Two at least of the corners are rounded and located inside of imaginary extensions of the flat lateral faces of the belt. They are connected to the edges of the lateral faces by gussets sloping radially inwardly.Type: GrantFiled: April 1, 1987Date of Patent: August 23, 1988Assignees: Framatome, Compagnie Generale des Matieres NucleairesInventors: Jean-Pierre Denizou, Bruno Mouesca
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Patent number: 4762669Abstract: In a nuclear reactor, the core is composed of fuel assemblies disposed in side-by-side spaced relationships with an outer group thereof defining the periphery of the core and an inner group thereof positioned inwardly of the outer group. A baffle structure extends about the reactor core adjacent the fuel assemblies in the outer group. Any jetting of coolant fluid through the baffle structure will impinge upon fuel rods in the outer group of fuel assemblies so as to cause vibration of the fuel rods. To prevent such vibration, a plurality of annular anti-vibration grids are axially spaced along and connected to guide thimbles of the fuel assemblies in the outer group thereof between at least some of the support grids of such fuel assemblies. The annular grids are separate from and unconnected to the support grids.Type: GrantFiled: May 13, 1987Date of Patent: August 9, 1988Assignee: Westinghouse Electric Corp.Inventor: Pratap K. Doshi
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Patent number: 4762676Abstract: A top nozzle adapter plate for use in a fuel assembly of a nuclear reactor includes an upper structural component and a lower functional component supported from the upper component. The fuel assembly has elongated structural members and fuel rods disposed in a predetermined array. The upper structural component of the adapter plate includes spaced and interconnected hubs and ligaments arranged to define substantial open areas for coolant flow therethrough while providing a rigid framework capable of transmitting lifting loads imposed by the fuel assembly. The hubs are connected to the elongated structural members of the fuel assembly.Type: GrantFiled: July 5, 1985Date of Patent: August 9, 1988Assignee: Westinghouse Electric Corp.Inventors: Robert K. Gjertsen, John F. Wilson, William E. Kirby
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Patent number: 4758403Abstract: A spacing grid is provided for a nuclear fuel assembly comprising two sets of intersecting metal plates having fins and defining fuel element receiving pockets. The plates comprise solely half-fins each associated with a single pocket of the grid, disposed in opposed pairs at the angles of the pockets, the half-fins of one pocket being placed at 90.degree. from the half-fins of adjacent pockets.Type: GrantFiled: November 5, 1985Date of Patent: July 19, 1988Assignee: FragemaInventor: Jean Noailly
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Patent number: 4756878Abstract: A marked reduction in the pressure drop of cooling liquid through a grid spacer of a nuclear fuel assembly is attained by convexly contouring the upstream (usually the lower) edges of the grid members. Preferably, they are made streamlined or semicylindrical. This can be done by first beveling and then etching them, by directing a stream of mixture of abrasive and an organic polymer against them, or by traversing an electron or laser beam along them at a power and velocity such as to cause local melting. A lesser improvement is secured by beveling alone. A still further improvement can be obtained by also tapering the downstream (usually upper) edges.Type: GrantFiled: December 1, 1986Date of Patent: July 12, 1988Assignee: Advanced Nuclear Fuels CorporationInventors: Peter P. King, John F. Patterson, Jack Yates, Charles A. Brown
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Patent number: 4749543Abstract: An improved channel is disclosed which has a reduced average thickness in its upper portion. The lesser average thickness corresponds to a lower pressure difference acting on the channel sides, over the upper portion of the channel. The reduction in average thickness is accomplished by cutting flow trippers into the inner surface of the channel walls and/or cutting grooves into the outer surface of the channel. The axial variation of channel average thickness increases water volume adjacent to the upper part of the channel to provide increased neutron moderation, to minimize the steam void reactivity coefficient, and to provide a greater cold shutdown margin. The material removed to produce the flow trippers increases the cross-sectional area inside the channel and reduces pressure drop in the upper portion of the channel. The flow trippers divert water flowing on the channel walls to the fuel rods adjacent to the channel walls, permitting higher reactor power operation.Type: GrantFiled: March 24, 1987Date of Patent: June 7, 1988Assignee: General Electric CompanyInventors: Russell L. Crowther, Eric B. Johansson, Bruce Matzner
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Patent number: 4749544Abstract: In a channel contained fuel bundle for a boiling water nuclear reactor, an improved channel is disclosed. The channel contains a plurality of fuel rods held in spaced apart relation by at least upper and lower tie-plates and/or spacers. In the reactor, the channel contains fuel rods extending between a lower support plate and an upper support grid. When the reactor is operating, the channel confines water flow intimately about the rod bundle on the inside and assures steam generation in a predictable pattern. Water exterior of the channel is at a different and typically lower pressure. To accommodate control blades (which control the fission process) outside of the fuel bundles, the channel is provided with a polygon cross section, most typically a square cross section. In operation, the flat walls tend to bulge due to primarily pressure effects but also due to thermal and radiation effects.Type: GrantFiled: March 24, 1987Date of Patent: June 7, 1988Assignee: General Electric CompanyInventors: Russell L. Crowther, Eric B. Johansson
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Patent number: RE33818Abstract: An improved channel is disclosed which has a reduced average thickness in its upper portion. The lesser average thickness corresponds to a lower pressure difference acting on the channel sides, over the upper portion of the channel. The reduction in average thickness is accomplished by cutting flow trippers into the inner surface of the channel walls and/or cutting grooves into the outer surface of the channel. The axial variation of channel average thickness increases water volume adjacent to the upper part of the channel to provide increased neutron moderation, to minimize the steam void reactivity coefficient, and to provide a greater cold shutdown margin. The material removed to produce the flow trippers increases the cross-sectional area inside the channel and reduces pressure drop in the upper portion of the channel. The flow trippers divert water flowing on the channel walls to the fuel rods adjacent to the channel walls, permitting higher reactor power operation.Type: GrantFiled: June 6, 1990Date of Patent: February 11, 1992Assignee: General Electric CompanyInventors: Russell L. Crowther, Jr. deceased, Eric B. Johansson, Bruce Matzner