摘要:
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. Both the apparatus and method of the invention are particularly well suited for installing plugs in tubes surrounded by relatively inelastic structures, such as tubesheets. Additionally, the invention conveniently and reliably plugs small diameter tubes in the peripheral regions of these tubesheets.
摘要:
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. In one embodiment this inflatable portion extends around the perimeter of the seal plate and is readily expandable. In another embodiment the inflatable portion includes inflatable pillows disposed between the seal plate and the anchor assembly and inflatable for completely closing the nozzle. A foldable tripod centering mechanism and a shaft tensioning tool are also disclosed.
摘要:
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.
摘要:
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. The elongation of the stud is then determined as a function of the difference in the correlated quantities of hydraulic fluid or the correlated differences in puller bar or piston travel at the first and second low pressures. Finally, the tensioner is detached from the stud.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.