General Electric Company

Siamak Bourbour

Gerald A Deaver

Henry Peter Offer

Grant Clark Jensen

Bryan K Chavez

Ron B Ninomiya

Arunachalam Mahadevan

John Geddes Erbes

Jeffrey L Thompson

David Bryan Drendel

Leonard John Sharpless

William F Bowen

Don Schrein

A clamp assembly connects a diffuser adapter or lower ring to a diffuser tail pipe of a jet pump diffuser in a boiling water nuclear reactor. The clamp assembly includes at least two clamp segments shaped generally corresponding to an exterior circumference of the diffuser, a swivel link affixed at each end of each of the clamp segments, and at least two connecting bands pivotably secured to the swivel links between the ends of the clamp segments. The clamp segments each includes a locking assembly engageable with the diffuser adapter or lower ring and the diffuser tail pipe. The clamp assembly structurally replaces/repairs the weld joining the diffuser adapter or lower ring and the diffuser tail pipe.

Method and apparatus for repairing a jet pump diffuser adapter to tailpipe weld

A component which has a surface crevice or crack and contaminants on at least one face of the opening is welded. The weld is effected by first plastically deforming the surface of the component to close the surface opening to a predetermined depth less than the depth of the opening and contaminated faces defining the opening to form a sealed ligament. The sealed ligament leaves unclosed a portion of the crack below the sealed ligament. The closed surface is hermetically sealed by fusion-welding to a depth of penetration equal to or less than the predetermined depth of the sealed ligament to minimize or eliminate expulsion of contaminants in the sealed ligament.

Fusion-welding of defective components to preclude expulsion of contaminants through the weld

A housing for an underwater processing device, for example, welding, includes a welding head movable laterally relative to the housing and the direction of the weld. At opposite ends, gates are provided having arcuate convex surfaces forming edge seals for engaging in the groove of the work surface. In one form, the gates are linearly slidable and biased in a direction away from the housing. In another form, the gates are pivotally mounted for engaging in the grooves. In both cases, the compliant seal about the margin of the housing, together with the arcuate seal of the gates, maintains a substantially water-free area within the housing to enable processing.

Apparatus and methods for submerged processing of a grooved work surface using a movable gate

A clamp assembly prevents separation of a thermal sleeve penetrating a nuclear reactor pressure vessel wall and a jet pump riser elbow welded one to the other and lying within an annular space between the pressure vessel wall and core shroud. The clamp assembly includes a pair of heads having semi-cylindrical recesses. Pins project inwardly from each of the heads in the semi-cylindrical recesses and have axes which lie parallel to one another. By using actuators mounting multiple electrodes, holes may be formed in situ in the adjoining ends of the thermal sleeve and elbow. Once the holes are formed, the heads can be applied in situ with the pins being received through the holes and the heads clamped to one another. Thug, the pins in each of the sleeve and elbow prevent separating movement of the sleeve and elbow in the event of failure of the welded joint therebetween.

Apparatus and methods for precluding separation of a thermal sleeve and elbow joint in the recirculation system of a nuclear reactor

An underwater exclusion device includes a housing for a welding torch having leading and trailing arrays of pivotal fingers for engaging in grooves along a work surface to exclude water from an exclusion area within the housing containing the welding torch. The fingers are pivotally mounted and independently and individually movable under the bias of springs between retracted and extended positions. The fingers have radiussed distal ends for engaging the work surface. Upon application of the device to the work surface, the leading and trailing arrays of fingers are displaced under spring pressure to engage their distal ends against the work surface, excluding water from within the housing. The side walls of the housing carry seals for seating along the work surface to prevent water incursion in gaps between the side walls and the work surface.

Apparatus and methods for processing a submerged work surface

Apparatus for supporting the lower elbow assembly of a jet pump in a reactor pressure vessel (RPV) of a nuclear reactor are described. The clamp apparatus includes a lower clamp element and an upper clamp element. The upper and lower elements are configured to be positioned at the interface between the thermal sleeve and the jet pump riser elbow. The upper and lower elements include extended ridges that are configured to fit in circumferential grooves precisely machined into the sleeve-elbow assembly on opposing sides of the interface.

Apparatus for performing jet pump riser pipe repairs

Methods and apparatus for supporting the lower riser assembly of a jet pump in a reactor pressure vessel (RPV) of a nuclear reactor are described. In one embodiment of the apparatus, the clamp apparatus facilitates applying compression force on the elbow. The clamp apparatus includes a lower elbow clamp, a riser clamp, and a bridge. The lower elbow clamp is positioned adjacent an interface between the elbow and the thermal sleeve of the jet pump riser pipe assembly. The riser clamp is secured to the riser pipe of the jet pump riser pipe assembly at a location adjacent an interface between the riser pipe and the elbow. The bridge rigidly couples the lower elbow clamp and the lower clamp so that as the respective clamps are secured to the lower riser assembly, a compression clamping force is placed on the piping and welds at each clamp.

Methods and apparatus for performing jet pump riser pipe repairs

Apparatus for supporting the lower riser assembly of a jet pump in a reactor pressure vessel (RPV) of a nuclear reactor. In one embodiment of the apparatus, the clamp assembly provides structural rigidity to the lower rise assembly. The clamp assembly includes a lower thermal sleeve clamp and a riser clamp. The lower thermal sleeve clamp is positioned adjacent an interface between the elbow and the thermal sleeve of the jet pump riser pipe assembly. The riser clamp is secured to the riser pipe of the jet pump riser pipe assembly at a location adjacent an interface between the riser pipe and the elbow. The lower thermal sleeve clamp and the riser clamp also are coupled to each other so that as the respective clamps are secured to the lower riser assembly.

A thermal sleeve for insertion into a feedwater nozzle bore of a reactor pressure vessel for a nuclear reactor is described. In one embodiment, the sleeve includes a substantially cylindrical main body and a substantially cylindrical interference ring. The interference ring has a first secured end and a second free end. The interference ring is connected at the first secured end to an exterior surface of the substantially cylindrical main body. An interference surface is located at the second free end of the ring. The second free end of the cylindrical interference ring is biased so that when the sleeve is positioned in the nozzle bore, the second free end is biased towards the nozzle bore wall. In one embodiment, the second free end is biased into contact with a surface of an outer sleeve which also is positioned in the nozzle bore. The connector, a nozzle safe end wall, the outer sleeve and the inner sleeve cooperate to define a stagnant water area. A first end of the thermal sleeve interfaces with a connector for connecting the sleeve to a feedwater line. A second end of the sleeve interfaces with a feedwater sparger T-box having openings for spraying water delivered by the feedwater line into the RPV.

Feedwater nozzle thermal sleeve

A nozzle includes a barrel being integral with a vessel and includes a first bore. A safe end is joined at one end to the barrel by a first weld and at an opposite end to an inlet pipe at a second weld. A first thermal sleeve is disposed inside the first bore and has one end disposed in an interference fit with a second bore of the safe end. In order to repair the nozzle for reducing leakage at the interference fit between the first and second bores, a method includes removing a portion of the inlet pipe and the weld at the safe end and installing a replacement extension therefor. The extension includes a tubular body having a first fork at one end joined to the safe end by a replacement weld, and having a distal end joined to the inlet pipe at a third weld. A second fork is disposed concentrically inside the body and is integrally joined at one end with an intermediate portion of the body, and includes a distal end extending toward the safe end. A second thermal sleeve is disposed inside the first thermal sleeve and is joined at one end to the second fork and has an opposite end portion disposed in sealing cooperation with the first thermal sleeve for sealing flow therebetween to the interference fit between the first thermal sleeve and the safe end.

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San Jose, CA, United States of America

Siamak Bourbour