Abstract: A device for aligning nuclear fuel pellets, for insertion into fuel rods, comprises a vibrating table and a conveyor assembly adapted to receive pellets poured from a container and to deposit them in a single layer on the table. The upper surface of the table is formed with a number of parallel, substantially v-shaped grooves in which the pellets become aligned. The conveyor assembly, which comprises a horizontal traveling belt and an inclined planar slide, is slid along above the table to facilitate the distribution of pellets thereon. An inspection station, adjacent the table, comprises a number of rotating, parallel rollers in columnar-flow communication with the table grooves. Aligned pellets from the table are delivered onto the rollers where they slowly rotate, presenting their circumferential surfaces for visual inspection. A displaceable control member, transversely disposed between the table and the inspection station, controls transfer of pellets therebetween.

Abstract: A permanent pool seal and neutron shield 30 for providing an effective water barrier over the annular space 28 between a nuclear reactor vessel flange 24 and a surrounding annular ledge 22 includes annular deck sections 32 supported on spaced ribs 46.Flexible membranes 50,52 on the deck section peripheries accommodate relative movement. Openings 42, each with a removable plug structure which includes cover 44 and tapered can 60, provide vessel cavity 14 with ventilation and maintenance access. All cans 60 and similar containers 56 and 59 under the deck structure and flange 24 contain a shielding material 58 in the form of a boron-containing concrete. Supported below the cans is refractory insulating material 54.

Abstract: A frame 10 with downwardly projecting members 52 mounts by means of a pair of hoists 36 and lifting bracket 42 downwardly into upwardly open recesses of complementary mounting members 54 secured to reactor head lifting legs 30. Frame 10 is mounted on the head either with lead wool shielding blankets 40 hanging from it or without. In the latter case, hangers 60 with blankets 40 hanging therefrom and horizontally gravity biased hooks 64 mounted on a curved beam 62, are lowered by hoist 36 until hooks 64 grapple, pivot and hang hanger 60 and the shielding on frame 10 at a location radially inwardly of the head bolt locations 22. The hook of hoist 36 is lowered until it is disengaged from the radially outwardly biased bail 70 of hanger 60.

Abstract: A multisectioned nozzle dam (30) for use in a steam generator (24) with an integral bolt ring (32) has a body structure of general circular shape. Redundant seals including at least three separate inflatable peripheral seals (48, 50 and 52) with an alarm (A) for indicating a pressure increase between the second and third seals (50 and 52) is provided. Redundant supports including a plurality of independent bars (60, 62, 64 and 66) bolted to the integral bolt ring (36) secure the dam (30) within the nozzle (26) to the appropriate axial position.

Abstract: A system and method for installing a nozzle dam unit (26) in a nuclear steam generator having a head (12) including a head internal surface, a manway (14) penetrating the head, and a nozzle (16) penetrating the head. The system comprises a manipulator (76) adapted to be passed through the manway and having open end (82) adapted to be attached remotely to the head internal surface and a free end including a clamp member (104). A plurality of nozzle dam segments (54, 56, 58) are each sized to pass through the manway and carry means thereon (120) for engaging at least one other segment, the segments when fully engaged to each other forming a dam subassembly sized to pass into and seat against the nozzle. The manipulator is controlled so that the clamp member grasps and supports one of the dam segments within the head until the subassembly is formed within the head, and then is translated within the head until the dam subassembly seats within the nozzle.

Abstract: A system and method for installing a nozzle dam unit (26) in a nuclear steam generator having a head (12) including a head internal surface, a manway (14) penetrating the head, and a nozzle (16) penetrating the head. The system comprises a manipulator (76) adapted to be passed through the manway and having one end (82) adapted to be attached remotely to the head internal surface and a free end including a clamp member (104). A plurality of nozzle dam segments (54, 56, 58) are each sized to pass through the manway and carry means thereon (120) for engaging at least one other segment, the segments when fully engaged to each other forming a dam subassembly sized to pass into and seat against the nozzle. The manipulator is controlled so that the clamp member grasps and supports one of the dam segments within the head until the subassembly is formed within the head, and then is translated within the head until the dam subassembly seats within the nozzle.

Abstract: A nuclear steam supply steam generator primary nozzle 16 is sealed by a nozzle dam having segmented bulkhead portions 42 and 45 with peripheral flanges 46,50,52. A rubber diaphragm with a body 54 and peripheral strata form oppositely opening cavities 56 and 58. Hydraulic pressure from either side enters one of the cavities to create a radial sealing force against the inside surface of nozzle 16. A closed cell foam rubber sealing material 76 of 20 to 30 durometer can be interposed between the cavity defining strata and the surface 16 to improve sealing. A hinged retaining ring 70 is pinned to hold the nozzle dam against radial surface 68 machined in nozzle 16.

Abstract: An annular plate is mounted on and sealed to the spaced apart pressure vessel flange and vessel containment structure of a nuclear reactor to form a leak-proof bottom for a refueling canal for the reactor. The sealing arrangement for the plate establishes redundant seals to each of the flange and containment structure, the seals being pneumatically expandable to enhance the integrity thereof.

Abstract: A modular radiation shielding system for use on the lower side of a nuclear steam generator tubesheet 14 to protect inspection and repair workers in the primary head 20 of the generator 10 from radiation of the tubesheet 14 and plurality of tubes 12 it secures. The modular assemblies each comprise a geometrically shaped lead panel 22 sheathed in a stainless steel box 30 with a transverse opening extending therethrough for alignment with a tube 12. A rapid installation tube gripper 40, which may have a lead nose for shielding, extends through the opening and into a tube 12 to hold the geometrically shaped modular assembly against the lower surface of the tubesheet 14.

Abstract: A nozzle between the nuclear steam generator and nuclear reactor vessel has a dam, plug, or barrier mounted on the tapering internal wall of the conduit. A seating ring is mounted on the tapered internal surface of the nozzle through screws which will ensure release of the ring after pressure on the dam is removed, and the screws are backed away from engagement with the tapered surface.

Abstract: A gripper device (24) for attachment to the inside of a tube (12) has a shaft member (26) including an upper tapered portion (30) surrounded by a generally cylindrical sleeve member (34) having at least two holes (38) opposite the tapered portion of the shaft. The sleeve outer diameter is slightly less than the inner diameter of the tube targeted for attachment. A spring (32) is connected between the shaft member and the sleeve member, for biasing the tapered shaft downwardly relative to the sleeve. A round bearing or hard ball (36) is located in each hole such that downward motion of the shaft relative to the sleeve urges the balls outwardly to protrude from the sleeve surface against the tube wall. The device is installed by pushing on stem (28) at the lower end of the shaft member to insert the device into the tube. A flange (44) is formed at the lower end of the sleeve to limit the sleeve insertion into the tube.

Abstract: A method for installing a close-fitting cylindrical metal sleeve (26) within a tube (14) secured to a tube sheet (12) of a steam generator, comprising the following steps. First, the sleeve is inserted into the tube until an upper portion (28) of the sleeve is above the tube sheet while the lowr portion (30) of the sleeve is within the tube sheet. Next, the upper portion of the sleeve is radially deformed against the adjacent tube wall to form substantially coextensive permanent bulges (32,34) around the circumferences of the sleeve and the tube. The sleeve is then displaced axially, or longitudinally, relative to the tube, such that the bulge in the sleeve produces a wedge-like mechanical interference seal (40) against the tube wall (16'). Finally, the lower portion (30,38) of the sleeve is joined and sealed (42) against the adjacent tube wall (16') to permanently maintain the tight mechanical interference seal at the upper portion of the sleeve.

Abstract: A nozzle plug (22) for blocking a nozzle (46) in a nuclear steam generator (16) is improved by the addition of hinges (40a, 40b) which allow the nozzle plug (22) to be inserted into the steam generator (16) through an access port (52) of substantially smaller diameter than the nozzle (46). A recess (54) is provided in one of the semi-circular plates (28) allowing the plates to nest, further reducing the necessary size of the access port (46).

Abstract: An apparatus for sealing a joint between two substantially collinear tubes (12,14) is provided. Particularly useful for repairing a welded joint which has developed a crack (20) in the area of the weld (18), the apparatus provides a sleeve (26) which fits closely over the cracked joint. A housing (32), surrounding the sleeve (26), and a thrust ring (38) act to compress packing rings (28,30) against the sleeve to form a fluid-tight seal over the leaking joint. The sealing nut (40) maintains compression on the packing rings (28,30) when the installation apparatus (50,60,70) is removed. A method for installing the sealing apparatus is also disclosed herein.

Abstract: A long, thin strip of spring steel functions as the support base for one or more capillary tubes. The strip and its attached capillary tubes are thrust through a handhole in the side of a vessel containing a tube bundle and diverted by a guide into predetermined open lanes formed by the tubes of the bundle. The forward ends of the capillary tubes are directed downward for the jetting of fluid under high pressure into a body of sludge collected between the tubes and on the upper side of the tubes and their tube sheet. The source of the fluid is connected to the rear ends of the capillary tubes as the supply of fluid under high pressure.

Abstract: A control rod suspended to reciprocate in a guide tube of a nuclear fuel assembly has a hydraulic bearing formed at its lower tip. The bearing includes a plurality of discrete pockets on its outer surface into which a flow of liquid is continuously provided. In one embodiment the flow is induced by the pressure head in a downward facing chamber at the end of the bearing. In another embodiment the flow originates outside the guide tube. In both embodiments the flow into the pockets produces pressure differences across the bearing which counteract forces tending to drive the rod against the guide tube wall. Thus contact of the rod against the guide tube is avoided.

Abstract: An apparatus for providing a high, positive locking force at the bottom of a nuclear fuel assembly to resist upward coolant flow forces. A latch on the fuel assembly alignment post is cammed to engage the fuel alignment pin in the core support stand and is linked to an actuating rod extending through the lower end of the fuel assembly center guide tube. The upward flow of coolant against the link and actuating rod causes the link to approach the horizontal, thereby exerting a high locking force between the latch and the fuel alignment pin. In the preferred embodiment spring means interact between the lower end fitting and the actuating rod to maintain an upward bias on the rod.