Abstract: Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening.

Abstract: Vessel structural support system for laterally and vertically supporting a vessel, such as a nuclear steam generator having an exterior bottom surface and a side surface thereon. The system includes a bracket connected to the bottom surface. A support column is pivotally connected to the bracket for vertically supporting the steam generator. The system also includes a base pad assembly connected pivotally to the support column for supporting the support column and the steam generator. The base pad assembly, which is capable of being brought to a level position by turning leveling nuts, is anchored to a floor. The system further includes a male key member attached to the side surface of the steam generator and a female stop member attached to an adjacent wall. The male key member and the female stop member coact to laterally support the steam generator.

Abstract: A system for removing sludge from a sludge-bearing fluid flowing in a vertically oriented nuclear steam generator so that the sludge is not present therein in sufficient quantities to corrode components (e.g., heat transfer tubes) located in the steam generator. The system comprises a tube sheet having a plurality of apertures therethrough for receiving the ends of the heat transfer tubes so that the tubes are supported by the tube sheet. The tube sheet has a top surface thereon and also a recess formed in the top surface for separating and for collecting the sludge from the sludge-bearing fluid. The recess has a substantially frusto-conical wall generally converging at the bottom end of the recess for providing a settling basin for the sludge after the sludge is separated from the sludge-bearing fluid. A pipe extends from adjacent the bottom end of the recess to the exterior of the heat exchanger for transporting the sludge from the recess to the exterior of the heat exchanger.

Abstract: A method is disclosed for making an apparatus for substantially eliminating flow induced vibrations of the flow tubes of a steam generator in the U-bend region. Antivibration bars are provided between columns of flow tubes in the U-bend region which are contoured on one side to correspond with the exact as-built and as-bent diameter of the tubes as located within the tube bundle. Measurements of the actual flow tube diameters are made and recorded and stored either on tape or in a computer which is then used to control a numerically operated machine which configures or machines cutouts in the antivibration bars to precisely correspond with the respective measured diameters of the flow tubes. Only one side of the antivibration bars need to be machined because of the flexibility of the flow tubes which allow the positioning of the other side of the flow tubes along a flat plane.

Abstract: A method of forming and installing anti-vibration bars into a tube bundle of a steam generator is disclosed. The tube bundle comprises rows of tubes, each tube carrying a high temperature coolant. Each of the resultant anti-vibration bars has a tubular configuration and is disposed between adjacent rows of the tube bundle for stabilizing the tubes against vibration caused by fluids recirculating at high velocities through the steam generator. The method of this invention comprises the steps of inserting at least one anti-vibration bar between adjacent rows of the tube bundle and applying a pressurized fluid in the anti-vibration, thus expanding the anti-vibration bar to contact the tubes of the adjacent rows and to make a series of indentations therein. Typically, the pressure of the fluid is increased incrementally up to a maximum level set such that the configuration of the steam genrator tubes is not deformed.

Abstract: A stayrod configuration for permitting complete sludge lancing of the tubesheet, including a plurality of first stayrods, each having the same diameter as the steam generator tubing and being threaded into the tubesheet at spaced positions which match the tube pattern. This plurality of first stayrods is attached to a connector, which is threaded to provide a receptacle for a second, full-length stayrod within a shortened spacer.

Abstract: Slots are provided in the wrapper of a nuclear steam generator to increase the local flexibility of the wrapper to allow for the difference in thermal expansion between the carbon steel wrapper and the high corrosion resistant alloy tube support members. The radial structural load paths between the tube support members, the wrapper, and the outer shell provided by the radial support means, about which the expansion slots are provided, are not affected by the addition of the expansion slots. Since the slots are preferably provided by means of a high speed industrial laser, they are very thin and do not permit substantial commingling of cooler downcomer water and the boiling mixture in the tube bundle region. The expansion slots may be vertically or horizontally oriented and may be cut into the wrapper on more than one side of the radial support means. The slots may end in small curved portions to decrease stress concentrations and increase fatigue life.

Abstract: A method and apparatus are disclosed for substantially eliminating flow induced vibrations of the flow tubes of a steam generator in the U-bend region. Antivibration bars are provided between columns of flow tubes in the U-bend region which are contoured on one side to correspond with the exact as-built and as-bent diameter of the tubes as located within the tube bundle. Measurements of the actual flow tube diameters are made and recorded and stored either on tape or in a computer which is then used to control a numerically operated machine which configures or machines cutouts in the antivibration bars to precisely correspond with the respective measured diameters of the flow tubes. Only one side of the antivibration bars need to be machined because of the flexibility of the flow tubes which allow the positioning of the other side of the flow tubes along a flat plane.

Abstract: A tube support plate is disclosed for supporting a plurality of tubes with reduced vibration in a nuclear steam generator. The support plate has a plurality of holes disposed therethrough in a regular array. Each hole has an axis, an interior surface and a plurality of lands supported on the interior surface and extending towards the axis. The support plate has a given thickness as taken along the hole axis, and each of the lands has a tapered surface for facilitating tube insertion. The method of forming the tube support plate comprises a first step of forming each of the holes through the support plate with a first cylindrical portion of a first diameter and a second cylindrical portion of a second diameter less than the first diameter. Next, portions of the second cylindrical portion are removed in a second step to form a plurality of lands having exposed ends supporting a tube within the hole.

Abstract: An improved, grid-type flow distribution baffle for both providing lateral support for an array of heat exchange tubes and for generating a sludge-sweeping water current within a steam generator is disclosed herein. Generally, the improved baffle comprises a plurality of grid members for defining an array of square, tube-capturing cells, wherein each wall of the cell is closely adjacent and contactable with the side of the tube. Each of the cells is circumscribed by a flange at one of its ends which includes a substantially circular opening for allowing the tube to extend through the cell. The flange includes four flat portions spaced 90.degree. apart for rendering the flange flush with the center portion of each of the square walls which form the cells of the baffle. These flat portions allow the flange to closely circumscribe the tube without coming into contact with it, thereby avoiding "point contact" between the flange and the tube.

Abstract: In a nuclear steam generating vessel, a baffle plate disposed a slight distance above the tube sheet has a plurality of openings therethrough for respectively receiving the heat exchanger tubes. Each opening has a circular central portion and eight equally spaced peripheral lobe portions alternating with eight lands. The inner end of the lands lie on a circle have a diameter slightly greater than that of the associated tube. The upper and/or lower surface of the baffle plate is mechanically deformed adjacent to each lobe portion of each opening to displace material into the lobe portions and constrict the cross sectional areas thereof to limit liquid flow therethrough. The lands are dimensioned and arranged so that one or two at a time can contact the associated tube, while the constriction of the lobe portion flow areas limits liquid flow therethrough sufficiently to insure proper baffling operation of the baffle plate.

Abstract: A plunger element which slides axially in a bore in a dashpot element secured to the internals of a steam generator is biased against the shell of the pressure vessel by a series of Belleville springs. The plunger and dashpot element form a chamber having a volume which varies as the width of the gap between the pressure vessel shell and internals changes due to differential thermal expansion, and pressure expansion of the shell. A collapsible reservoir provides an incompressible fluid to the variable volume chamber under urging of the ambient pressure in the pressure vessel through a metering passageway to maintain the chamber full of fluid.

Abstract: A tube support grid for supporting a plurality of closely packed tubes utilizing punched bars with a plurality of resilient and stiff fingers punched into the bar and so disposed that when the bars are assembled into an egg-shaped grid, the tubes are supported on opposite sides by a resilient and a stiff finger extending from the bars.