Abrégé

Disclosed therein are an apparatus for and a method of welding a flange to a guide thimble tube in a nuclear fuel assembly. The automatic welding apparatus includes a welding unit located on an axially conveying line of a tube for welding a surface of the tube inserted thereinto and a surface of a flange, a flange supplying unit for supplying the flange at a tube inlet of the welding unit onto the axially conveying line, and a conveying unit mounted on the axially conveying line in such a way as to move the tube and the flange on the axially conveying line, so that they are inserted into and drawn from the welding unit.

Classes IPC  ?

• B23K 5/22 - Matériel auxiliaire, p. ex. supports de soudage, guides
• B23K 9/028 - Soudage de joints continusSupportsPièces rapportées pour des joints curvilignes situés dans un plan
• B23K 31/02 - Procédés relevant de la présente sous-classe, spécialement adaptés à des objets ou des buts particuliers, mais non couverts par un seul des groupes principaux relatifs au brasage ou au soudage
• B23K 11/00 - Soudage par résistanceSectionnement par chauffage par résistance
• G21C 21/02 - Fabrication des éléments combustibles ou surrégénérateurs à l'intérieur de gaines non-actives
• B23K 33/00 - Extrémités de pièces spécialement profilées pour effectuer des assemblages brasés ou soudésRemplissage des joints continus ainsi formés
• B23K 37/02 - Chariots pour supporter l'outillage pour souder ou découper
• B23K 37/04 - Dispositifs ou procédés auxiliaires non spécialement adaptés à un procédé couvert par un seul des autres groupes principaux de la présente sous-classe pour maintenir ou mettre en position les pièces
• B23K 37/053 - Alignement des pièces cylindriquesDispositifs de serrage à cet effet
• G21C 3/326 - Faisceaux d'éléments combustibles en forme d'aiguilles, de barres ou de tubes parallèles comprenant des éléments combustibles de différentes compositionsFaisceaux d'éléments combustibles en forme d'aiguilles, de barres ou de tubes parallèles comprenant, en plus des éléments combustibles, d'autres éléments en forme d'aiguille, de barre ou de tube, p. ex. barres de commande, barres de support de grilles, barres fertiles, barres à poison ou barres factices

Abrégé

A hold-down spring unit for a top nozzle of a nuclear fuel assembly. The hold-down spring unit is coupled to the upper end of the top nozzle of the nuclear fuel assembly. The hold-down spring unit includes a first spring which provides a hold-down force upon the nuclear fuel assembly under start-up conditions or hot full power conditions of a nuclear reactor, and a second spring which provides an additional hold-down force upon the nuclear fuel assembly under start-up conditions of the nuclear reactor. The hold-down margin under start-up conditions or hot full power conditions is reduced, thus enhancing the mechanical and structural stability of the nuclear fuel assembly.

Classes IPC  ?

• G21C 1/22 - Réacteurs hétérogènes, c.-à-d. dans lesquels le combustible et le modérateur sont séparés utilisant du combustible liquide ou gazeux
• G21C 19/28 - Dispositions pour introduire un matériau fluent à l'intérieur du cœur du réacteurDispositions pour enlever un matériau fluent du cœur du réacteur
• G21C 9/00 - Dispositions pour la protection d'urgence structurellement associées avec le réacteur
• G21C 23/00 - Dispositions dans les réacteurs pour faciliter les expériences ou l'irradiation
• G21C 1/04 - Réacteurs thermiques

Abrégé

Disclosed is a spacer grid assembly with mixing vanes supporting fuel rods of nuclear fuel assemblies and mixing coolant that flows around the fuel rods, and more particularly, a spacer grid equipped with mixing vanes that mix coolant flowing around fuel rods. The spacer grid with hydraulically balanced mixing vane patterns, in the spacer grid equipped with a strip dividing a plurality of unit grid cells and a plurality of springs, protruded in uniform directions of vertical and horizontal directions on a grid surface of the strip and supporting nuclear fuel rods, which includes: a plurality of mixing vanes protruded to the downstream of coolant on an upper end of the inner grid surface, wherein positions and directions of the mixing vanes are formed in regular patterns on the spacer grid. Thus, it can minimize coolant flow induced vibration of the spacer grid by balancing hydraulic load generated by the mixing vanes, around the center of the spacer grids.

Classes IPC  ?

• G21C 3/34 - Grilles d'espacement

Abrégé

A top nozzle is provided. The top nozzle can include a coupling plate, a perimeter wall and a hold-down spring unit. The coupling plate can be coupled to a guide thimble of the nuclear fuel assembly. The perimeter wall can protrude upwards from the perimeter of the coupling plate. A spring clamp can be provided on the upper surface of the perimeter wall. The hold-down spring unit can be mounted to the upper surface of the perimeter wall in such a way to couple a corresponding end of the hold-down spring unit to the spring clamp. A fastening pin hole can be vertically formed through an upper surface of the spring clamp. A spring insert hole into which the hold-down spring unit can be inserted and formed by electro-discharge machining in an insert direction of the hold-down spring.

Classes IPC  ?

• G21C 21/00 - Appareillage ou procédés spécialement adaptés pour la fabrication des réacteurs ou de pièces de ceux-ci
• G21C 21/16 - Fabrication des éléments combustibles ou surrégénérateurs à l'intérieur de gaines non-actives par techniques de moulage ou de trempe
• G21C 3/33 - Moyens pour supporter ou suspendre des éléments dans le faisceauMoyens faisant partie du faisceau pour l'insérer dans le cœur ou l'en extraireMoyens de couplage de faisceaux adjacents

Abrégé

A machine and a method for grinding a spacer grid of a nuclear fuel assembly. The machine includes a spacer grid holding unit, a first rectangular coordinates robot for grinding an outer surface of the spacer grid, a second rectangular coordinates robot for grinding a corner of the spacer grid, and a control unit. The spacer grid holding unit includes a holding jig onto which the spacer grid is seated and held, and a rotary index table which is coupled to the holding jig to rotate the holding jig. The first and second rectangular coordinates robots are provided at predetermined positions adjacent to the spacer grid holding unit. The control unit controls the spacer grid holding unit, the first and second rectangular coordinates robots and all programs required to conduct the operation for grinding the spacer grid.

Classes IPC  ?

• G06F 19/00 - Équipement ou méthodes de traitement de données ou de calcul numérique, spécialement adaptés à des applications spécifiques (spécialement adaptés à des fonctions spécifiques G06F 17/00;systèmes ou méthodes de traitement de données spécialement adaptés à des fins administratives, commerciales, financières, de gestion, de surveillance ou de prévision G06Q;informatique médicale G16H)

Abrégé

A guide thimble plug for a nuclear fuel assembly is provided, in which an internal threaded hole is formed through a main body so that the main body is coupled to a bottom nozzle by a screw coupling. An upper insert part is formed in the upper end of the main body. The upper insert part is inserted into a shock absorption tube. A thermal deformation prevention part is formed on the main body below the upper insert part and is recessed inward from the outer surface of the main body such that, when the main body is coupled to the guide thimble, a gap is defined between the thermal deformation prevention part and the guide thimble. The guide thimble and the shock absorption tube can be reliably fastened to the bottom nozzle, and thermal deformation of the guide thimble can be minimized.

Classes IPC  ?

• G21C 5/04 - Dispositions spatiales permettant le gonflement Wigner
• G21C 3/32 - Faisceaux d'éléments combustibles en forme d'aiguilles, de barres ou de tubes parallèles
• G21C 3/33 - Moyens pour supporter ou suspendre des éléments dans le faisceauMoyens faisant partie du faisceau pour l'insérer dans le cœur ou l'en extraireMoyens de couplage de faisceaux adjacents

Abrégé

A hold-down spring unit for a top nozzle of a nuclear fuel assembly. The hold-down spring unit is coupled to the upper end of the top nozzle of the nuclear fuel assembly. The hold-down spring unit includes a first spring which provides a hold-down force upon the nuclear fuel assembly under start-up conditions and hot full power conditions of a nuclear reactor, and a second spring which provides an additional hold-down force upon the nuclear fuel assembly under start-up conditions of the nuclear reactor. The hold-down margin under start-up conditions and hot full power conditions is reduced, thus enhancing the mechanical and structural stability of the nuclear fuel assembly.

Classes IPC  ?

• G21C 3/32 - Faisceaux d'éléments combustibles en forme d'aiguilles, de barres ou de tubes parallèles

Abrégé

A method of measuring a gadolinia content using inductively coupled plasma-atomic emission spectrometry is provided. The method can include grinding sintered gadolinium using a percussion mortar to obtain a ground sample; warming the ground sample and then dissolving it with an acid solution to obtain dissolved gadolinia; diluting the dissolved gadolinia with distilled water to obtain a diluted gadolinia solution; measuring mass of each of a uranium element and a gadolinium element in the diluted gadolinia solution by a unit of ppm using the inductively coupled plasma-atomic emission spectrometry; and calculating a molar fraction of gadolinium from the diluted gadolinia solution and then calculating the gadolinia content using the molar fraction of gadolinium.

Classes IPC  ?

• G01J 3/30 - Mesure de l'intensité des raies spectrales directement sur le spectre lui-même

Abrégé

A suspension type high-density storage rack for nuclear fuel assemblies may include a plurality of body parts each having a basket cell storing the corresponding nuclear fuel assembly and having a generally square tube-like shape elongated in a height direction thereof, a plurality of connection plates integrally connecting the basket cells adjacent to each other, while maintaining them at a predetermined distance, and a base plate fixedly coupling the undersides of the basket cells thereto; and a plurality of cap parts each closing the opened upper portion of the corresponding body part and suspending the corresponding nuclear fuel assembly therefrom.

Classes IPC  ?

• G21C 19/00 - Dispositions pour le traitement, pour la manipulation, ou pour faciliter la manipulation, du combustible ou d'autres matériaux utilisés à l'intérieur du réacteur, p. ex. à l'intérieur de l'enceinte sous pression
• G21C 19/07 - Râteliers de stockagePiscines de stockage

Abrégé

Disclosed is an apparatus for performing an automated cleaning of nuclear fuel cladding-tubes. The apparatus comprises a pre-cleaning holding section disposed at a first side of the apparatus, a primary cleaning-material supplying section and a primary cleaning section disposed at a second side of the apparatus, a secondary cleaning section and a secondary cleaning material supplying section disposed at the second side of the apparatus and beside the primary cleaning section, an inspection section disposed at a third side of the apparatus that is opposite to the second side, and a post-cleaning holding section disposed at the fourth side of the transferring section. The pre-cleaning holding section and the post-cleaning holding section includes a cladding-tube guide where the cladding-tube is loaded before and after cleaning. Primary and secondary cleaning material supply sections are disposed at a lateral side of the primary and secondary cleaning sections respectively.

Classes IPC  ?

• G21C 19/42 - Retraitement des combustibles irradiés

Abrégé

Disclosed are a bottom spacer grid with a louver on a spring that can filter debris flowed through a channel of a lower end fitting with coolant on the lower end fitting of a nuclear fuel assembly, and can prevent uplift of fuel rods due to coolant, simultaneously. The bottom spacer grid for debris filtering with the louver for preventing uplift of the fuel rods, in the spacer grid equipped with a strip dividing a plurality of unit grid cells and a plurality of springs, protruded in uniform directions of each of vertical and horizontal directions on a grid surface of the strip, having uniform elasticity and supporting a lower end cap of a nuclear fuel rod, which includes: a spring having a plane portion with a predetermined size to contact to an outer circumference of the bottom end cap of the nuclear fuel rod; a louver protruded downward the spacer grid at a predetermined angle from the plane portion of the spring; and a debris filtering member bent and protruded to the bottom of the grid surface of the spacer grid.

Classes IPC  ?

• G21C 3/34 - Grilles d'espacement

Abrégé

The present invention relates to a top nozzle for a nuclear fuel assembly that has a two-stage elastic section such that a pushing force against the axial movement of the nuclear fuel assembly under normal conditions is optimized and at the same time a suppressing force against a drastic uplifting force of the nuclear fuel assembly under transient conditions is strengthened, and that lowers the elastic coefficients of the springs operating under normal conditions more than those of existing coil springs, thereby providing an optimal pushing force against the nuclear fuel assembly.

Classes IPC  ?

• G21C 15/00 - Dispositions pour le refroidissement à l'intérieur de l'enceinte sous pression contenant le cœurEmploi de réfrigérants spécifiques

Abrégé

Disclosed therein are an apparatus for and a method of automatically welding a flange to a guide thimble tube in a nuclear fuel assembly. The automatic welding apparatus includes: a welding part located on an axially conveying line of a tube for welding a welded surface of the tube inserted thereinto and a welded surface of a flange; a flange supplying part for supplying the flange at a tube inlet of the welding part onto the axially conveying line; and a conveying part mounted on the axially conveying line in such a way as to move the tube and the flange on the axially conveying line, so that they are inserted into and drawn from the welding part.

Classes IPC  ?

• B23K 37/00 - Dispositifs ou procédés auxiliaires non spécialement adaptés à un procédé couvert par un seul des autres groupes principaux de la présente sous-classe
• B23K 37/04 - Dispositifs ou procédés auxiliaires non spécialement adaptés à un procédé couvert par un seul des autres groupes principaux de la présente sous-classe pour maintenir ou mettre en position les pièces
• B23K 11/00 - Soudage par résistanceSectionnement par chauffage par résistance
• B23K 9/028 - Soudage de joints continusSupportsPièces rapportées pour des joints curvilignes situés dans un plan
• B23K 31/02 - Procédés relevant de la présente sous-classe, spécialement adaptés à des objets ou des buts particuliers, mais non couverts par un seul des groupes principaux relatifs au brasage ou au soudage
• B21J 13/08 - Accessoires pour la manipulation des pièces ou des outils

Abrégé

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.

Classes IPC  ?

• G21C 3/34 - Grilles d'espacement

Abrégé

The present invention relates to an apparatus and method for capturing an image of a welding spot during a welding task and determining an accurate position of the welding spot based on the captured image in order to perform an accurate welding task. A beam splitter splits a path of light reflected from a welding section of a spacer grid from a path of a laser beam generated from a laser generator. An image sensor receives light reflected from a welding spot of the spacer grid, and senses and stores an image of the spacer grid. Welding control means controls the image sensor to capture the image of the spacer grid, receives the image of the spacer grind from the image sensor, calculates an accurate position of the welding spot based on the received image, corrects position information of the welding spot based on the calculated position, and controls a servo motor so that the laser generator can accurately collimate the welding spot based on the corrected position value.

Classes IPC  ?

• B23K 26/00 - Travail par rayon laser, p. ex. soudage, découpage ou perçage