Abstract: A pipe clamp for reinforcing a welded joint between two pipes, having a plurality of circumferential clamp segments that are bolted together around the joint. One axial end of the clamp has circumferentially extended ridges that project inward and seat in corresponding circumferential grooves in a pipe on one side of the joint. The other axial end of the clamp has circumferentially spaced fingers that extend inward and fit into corresponding pockets on the other side of the weld joint. Either or both the ridges or the fingers have a taper whose cross-section reduces in an inward direction and fits in complimentary grooves or pockets on either side of the joint. The taper forces the opposite sides of the weld joint toward each other as the clamp segments are tightened together.

Abstract: A pipe clamp for reinforcing a welded joint between two pipes, having a plurality of circumferential clamp segments that are bolted together around the joint. One axial end of the clamp has circumferentially extended ridges that project inward and seat in corresponding circumferential grooves in a pipe on one side of the joint. The other axial end of the clamp has circumferentially spaced fingers that extend inward and fit into corresponding pockets on the other side of the weld joint. Either or both the ridges or the fingers have a taper whose cross-section reduces in an inward direction and fits in complimentary grooves or pockets on either side of the joint. The taper forces the opposite sides of the weld joint toward each other as the clamp segments are tightened together.

Abstract: The tension in a stud is verified by determining the elongation of the stud while attached to a stud tensioner during the tensioning step. The pressure of hydraulic fluid in a hydraulically actuated tensioner is increased from a first low pressure to a higher pressure for elongating the stud while correlating the increase in pressure of the hydraulic fluid with the quantity of hydraulic fluid in the tensioner or with the displacement of a tensioner puller bar or piston. After a nut is tightened on the stud, the pressure of the hydraulic fluid is reduced from the higher pressure to a second low pressure while correlating the decrease in pressure of the hydraulic fluid with the travel of the puller bar or piston or correlating the decrease in pressure of the hydraulic fluid with the change in fluid volume.

Abstract: Disclosed is a means for increasing coolant flow through the areas adjacent to where the removable top head closure is bolted to the body of pressurized water nuclear reactor. A circumferential plenum for coolant is provided between the upper flange of the core barrel, the inner wall of the pressure vessel body and the upper circular support plate and providing a plurality of orifices for coolant in the upper flange of the core barrel and the upper circular support plate whereby a coolant may be circulated through the core barrel flange, the circumferential plenum and the upper support plate and into the space enclosed by the removable top closure head.

Abstract: The guide pin aligning a top nozzle of a nuclear fuel assembly to an upper core plate of a nuclear reactor, is replaced working exclusively from below the upper core plate. The replacement guide pin has a shaft portion engaged with the upper core plate and the clamping nut which held the original guide pin, by threadable connection and/or by an expansion fitting. A shoulder on the pin bears against a lower surface of the upper core plate, and a nose of the pin is received in the top nozzle of the fuel assembly. A preferred expansion fitting has a bushing with ridges on its outer surface and a conical inside surface, and is inserted into the bored out original guide pin shaft. A threaded conical plug is pulled axially with rotation of the replacement pin shaft to expand the bushing. The ridges rigidly lock the replacement pin between the shoulder and the clamping nut.

Abstract: Both an apparatus and method for plugging a conduit, such as a tube in the tubesheet of a nuclear steam generator, is disclosed herein. The plugging apparatus generally comprises an inelastically expandable plug that contains a fluid-receiving cavity, and an expansion means including both a source of pressurized hydraulic fluid and a pull-rod member having a piston for advantageously applying both a radially expansive force and a compressive force to the plug at the same time in order to inelastically expand it into sealing engagement with the inner wall of a tube. In the apparatus of the invention, the compressive force exerted on the plug by the pull-rod member not only serves to inelastically deform the plug into a radially expanded shape, but is also used to seal the open end of the plug so that the pressurized hydraulic fluid admitted within the cavity of the plug will not escape.

Abstract: A tube protection device is positioned within a heat exchange tube of a nuclear steam generator to span a defect region and protect same against damage or deformation during withdrawal of the tube from the generator for subsequent defect analysis and testing. The tube protection device includes gripper means at the opposite ends thereof which are expansible from a relaxed condition permitting movement of the device through the tube to a clamped condition, releasably, frictionally engaging the contiguous interior sidewall surfaces of the tube at positions respectively spaced from the defect and spanning the defect region. An installation tool includes an elongaged linkage mechanism insertable through an open end of the tube for positioning the tube protection device and for operating same from the accessible portion of the linkage mechanism exterior to the open end of the tube between said relaxed and clamped conditions, and for remote withdrawal of the tube protection device from the tube.

Abstract: A nozzle dam for providing a fluid-tight seal across a primary fluid nozzle in the plenum of a nuclear steam generating vessel includes an elongated shaft coupled at one end thereof to an anchor assembly frictionally engageable with the inner surface of the nozzle to anchor the dam in place and a fluid-impermeable seal apparatus coupled to the shaft and closing the nozzle and frictionally engageable with the inner surface thereof to form a fluid-tight seal. The seal apparatus includes a circular plate disposable in wedging frictional engagement with a frustoconical portion of the nozzle inner surface. The shaft extends through a central aperture in the plate and is threadedly engaged with a nut which holds the plate in place. The anchor assembly includes a foldable tripod arrangement coupled to the shaft in such a way that movement of the shaft toward the seal plate effects an increase in the frictional anchoring force. The seal assembly also includes an inflatable portion.

Abstract: A flexible vibration stabilizer and method for reducing vibration in a tube in a shell and tube heat exchanger wherein the stabilizer is an elongated flexible cable or chain which may have a plurality of rigid members loosely or fixedly mounted thereon. A plug may be used for simultaneously mounting the stabilizer to the tube and for sealing same.

Abstract: Both an apparatus and a process for pulling tubes from a tubesheet with two relatively movable gripping means are disclosed herein. The apparatus of the invention is a tube puller which has upper and lower gripping means for gripping the section of the tube surrounded by the tubesheet. The two gripping means are mechanically linked together by means of an extendable connecting assembly. This assembly includes an outer sleeve where the lower gripping means is located, and a middle sleeve where the upper gripping means is located which is slidable a predetermined distance within the outer sleeve. In the process of the invention, a tube puller as heretofore described is inserted into the mouth of a tube. The lower gripping means is then engaged to the mouth of the tube. The upper gripping means is then engaged in a section of the tube beyond the tube mouth with the extendable connecting assembly in a contracted position.

Abstract: A sludge lance nozzle for removing sludge from between the tubes of a nuclear steam generator includes positioning apparatus mounted on top of the nozzle. The positioning apparatus includes a cylindrical eddy-current sensor mounted inside a cup-shaped non-magnetic electrically insulating spacer, which is in turn mounted in a cup-shaped support member fixedly secured to the nozzle. The tubes are arranged in rows and columns with the axes of the tubes in each column lying in a common column plane. The nozzle is moved perpendicular to the column planes close to one of the rows of tubes. The sensor produces a maximum-amplitude output signal when the sensing axis is coplanar with the column plane of a tube in the closest row of tubes and a minimum-amplitude output signal when the sensing axis is midway between adjacent tubes in the closest row of tubes.

Abstract: A multiple tube pulling apparatus for pulling, at one time, a plurality of stub-tubes from the tubesheet of a steam generator. Each tube gripping apparatus of the plurality is expanded into gripping arrangement by an axially retracted tapered rod. As the internal diameter of each stub-tube can vary, the amount of axial movement of each tapered rod to provide proper gripping engagement also varies. The present invention provides a single hydraulic cylinder for axially moving the plurality of tapered rods and includes spring members connecting each tapered rod to the hydraulic cylinder to accommodate the variations in axial movement of each rod necessary to obtain the proper gripping engagement for each stub tube. Further, a spring biased guide block maintains the gripping tubes on proper centers corresponding to the stub-tube centers and once the stub-tubes are removed from the tubesheet, the guide block pushes the stub-tubes off the tube gripping apparatus freeing the apparatus for another operation.

Abstract: A spacer and block cutting torch is lowered through the wrapper-to-shell annulus of a removed-top steam generator by addition of vertical sections of hollow-back column by vertical movement of a motorized carriage along a rack-and-guide track extending upwardly from atop the wrapper and manipulation of column clamps, one movable with the carriage and the other affixed to the wrapper, to transfer column weight from carriage to wrapper-top during adding and subtracting column sections. The rearward concave side of the column, held flush with the wrapper wall, readily accepts and serves to enclose operating gas hoses for the cutting torch. Yieldable bias means cooperates with the interior of the generator shell to urge the concave side of the column toward the wrapper.

Abstract: One or more pairs of vertically-spaced-apart sidewardly-aimable plasma arc cutting torches, the upper one angled upward and the bottom one downward, on the end of a horizontal boom movable longitudinally fore and aft and angularly sideward, are used to double-cut the tube bundle of a steam generator progressively in a manner clearing a path that accommodates torch assembly advancement.

Abstract: Apparatus which can be remotely mounted in a tube in a tube sheet provides a platform for mounting a camera. The platform rotates about a shaft extending from the tube, tilts, and moves axially along the shaft to allow the camera to pan the entire tube sheet and equipment utilized to work thereon.

Abstract: Cutting apparatus having spaced apart cutters which can be brought closer together are disposed on one end of a boom which is movable in a plane transverse to the longitudinal axis of a closely packed tube bundle to cut out short segments from the tubes starting at the periphery and working through the tube bundle by bringing the cutters closer together to provide clearance as the cutters move deeper into the tube bundle.