Abstract: A method and apparatus for repairing and/or reinforcing a Boiling Water Reactor (BWR) jet pump riser pipe. The repair includes attaching two collars to the riser pipe using match drilling to drill holes through the collars and the riser pipe and plugging the holes with expandable plugs. Support columns are attached to the collars. Brace supports are slideably attached to the support columns. Gaps between each brace support and its respective collar are then narrowed as ratchet bolts may apply a force that pulls downward on an upper collar and pulls upward on a lower collar, thereby exerting a compression force on the riser pipe. A clamp assembly may also be located between the two collars that applies a hoop force on the riser pipe.

Abstract: A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump three point slip joint clamp to mitigate sleep joint leakage flow induced vibration of a BWR jet pump assembly. A collar, provided as one seamless component or in separate portions, is installed on the upper crown of a diffuser. The collar includes a lower set of fasteners and an upper set of fasteners that contact the inlet mixer and diffuser, respectively, to horizontally stabilize the inlet mixer in a fixed position inside of the diffuser. The upper fasteners may be anchored by bosses that ensure a light-weight design of the collar. An optional cantilevered seal (including a cantilevered overhang and a lip) may mitigate leakage from the slip joint interface.

Abstract: A method and apparatus for repairing and/or preventatively maintaining a jet pump restrainer assembly used in a Boiling Water Reactor (BWR), the repair including attaching a bearing plate or plates to a horizontal surface of a jet pump restrainer assembly bracket, the bearing plate or plates acting to supplement and/or replace an existing contact surface between a mixer wedge and the jet pump restrainer assembly bracket of a jet pump restrainer assembly.

Abstract: Disclosed are various wedges that may be used in a restrainer bracket of a jet pump assembly. The jet pump assembly may include a restrainer bracket having an upper bracket and a lower bracket connected to an inlet mixer. A wedge may be provided between the upper bracket and the lower bracket and a wedge rod may pass through a slotted hole of the wedge. Ends of the wedge rod may be attached to the upper and lower brackets. The restrainer bracket may further include a yolk-like member which surrounds the inlet mixer and is connected to a riser pipe. The wedge may include an inclined surface which is configured to engage with a restrainer bracket pad of the yolk-like member. The wedges may further include inner curved surfaces which contact the wedge rod and the inner curved surfaces may be part of an insert that may be inserted in the wedge.

Abstract: Hard stops are useable in an operating nuclear reactor to separate and bias restrainer brackets and inlet mixers. Hard stops include a lip clamp that clamps to a restrainer bracket and a wedge member that biases against the inlet mixer. The wedge member and lip clamp are engaged such that the two components can slide against one another to bias the restrainer bracket and inlet mixer. The lip clamp includes a clamp arm and an engagement member to clamp opposite sides of the restrainer bracket. Ratchet assemblies maintain selective positioning various components of the hard stops. Hard stops may be used in several different numbers, positions, and configurations in repair or modification systems. Hard stops may be installed by determining location on an outside of a restrainer bracket for the hard stop, securing the hard stop at the location, and biasing the hard stop between two components at the location.

Abstract: A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump inlet-mixer integral slip joint clamp to constrain the inlet mixer and diffuser to mitigate inlet mixer flow induced vibration of a BWR jet pump assembly. The slip joint clamp includes horizontally projecting flanges with vertical sidewalls that protrude toward a lowest distal end of the inlet mixer. Fasteners penetrating the flanges provide a biasing load on the diffusers by being tightened to press against an upper crown on the diffuser. One or more flanges may be used. Laterally disposed gaps between the flanges may provide a clearance for guide ears of the diffuser to fit between the flanges.

Abstract: An apparatus for controlling movement of a first component integrated with a second component may include a first clamp configured to engage the first component, a second clamp configured to engage the second component, and a plurality of connectors configured to connect the first and second clamps. The connectors may allow movement of the first clamp relative to the second clamp in a first direction between the first and second clamps. The connectors may limit movement of the first clamp relative to the second clamp in a second direction perpendicular to the first direction.

Abstract: Disclosed are various torsional restraint systems for torsionally restraining a jet pump assembly, wherein the jet pump assembly includes a riser pipe, a transition assembly on the riser pipe, and a restrainer bracket connecting a first and a second inlet mixer to the riser pipe. The torsional restraint system includes a first contact member operatively attached to a side of the jet pump assembly and a second contact member operatively attached to the side of the jet pump assembly and disposed from the first contact member such that the first and second contact members restrain the riser pipe from rotating about a centerline of the riser pipe.

Abstract: A method and apparatus for a Boiling Water Reactor (BWR) jet pump slip joint internal seal for an interface between an inlet mixer and a diffuser of a jet pump assembly. The internal seal effectively mitigates leakage and slip joint flow induced vibration (FIV) between the inlet mixer and diffuser to reduce damage to many of the jet pump assembly components. A metallic seal of the slip joint internal seal flares out to conform the internal seal to a range of gap sizes, and compresses or springs back to nominal dimensions as thermal expansion and contraction occurs. The internal seal is self-expanding/self-tightening, as the internal seal flares further outward as a result of the internal pressure caused by flowing fluids in an operating jet pump assembly.

Abstract: An embodiment of the present invention provides an apparatus and system for repairing and/or maintaining a position of a first component in relation to a second component. The first and second components may be located within a reactor pressure vessel of a nuclear powerplant. The apparatus and system may attach at least one bearing plate to a horizontal surface of the first component. The apparatus and system includes structure to apply a pre-load to the first component. This may assist in maintaining the position of the first component relative to the second component.

Abstract: A method and apparatus for a boiling water reactor (BWR) jet pump inlet mixer compliant stop. The inlet mixer compliant stop may be installed in a pocket area between a riser pipe and an inlet mixer of a BWR jet pump assembly. The inlet mixer compliant stop includes a main body and a foot that are separated via the tightening of one or more jacking bolts used to connect the main body and the foot. A cold spring attached to the main body provides a lateral force that is imparted on the inlet mixer, to force the inlet mixer away from a centerline of the riser pipe. A precise lateral force may be imparted on the inlet mixer by gauging a width of a gap between opposing bosses on a front face of the main body and a distal end of the cold spring. The inlet mixer compliant stop imparts a greater lateral force on the inlet mixer as the jacking bolts are tightened, further separating the main body from the foot, as the gap between the opposing bosses is reduced.

Abstract: A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump inlet-mixer integral slip joint clamp to constrain the inlet mixer and diffuser to mitigate inlet mixer flow induced vibration of a BWR jet pump assembly. The slip joint clamp includes horizontally projecting flanges with vertical sidewalls that protrude toward a lowest distal end of the inlet mixer. Fasteners penetrating the flanges provide a biasing load on the diffusers by being tightened to press against an upper crown on the diffuser. One or more flanges may be used. Laterally disposed gaps between the flanges may provide a clearance for guide ears of the diffuser to fit between the flanges.

Abstract: A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump three point slip joint clamp to mitigate sleep joint leakage flow induced vibration of a BWR jet pump assembly. A collar, provided as one seamless component or in separate portions, is installed on the upper crown of a diffuser. The collar includes a lower set of fasteners and an upper set of fasteners that contact the inlet mixer and diffuser, respectively, to horizontally stabilize the inlet mixer in a fixed position inside of the diffuser. The upper fasteners may be anchored by bosses that ensure a light-weight design of the collar. An optional cantilevered seal (including a cantilevered overhang and a lip) may mitigate leakage from the slip joint interface.

Abstract: Hard stops are useable in an operating nuclear reactor to separate and bias restrainer brackets and inlet mixers. Hard stops include a lip clamp that clamps to a restrainer bracket and a wedge member that biases against the inlet mixer. The wedge member and lip clamp are engaged such that the two components can slide against one another to bias the restrainer bracket and inlet mixer. The lip clamp includes a clamp arm and an engagement member to clamp opposite sides of the restrainer bracket. Ratchet assemblies maintain selective positioning various components of the hard stops. Hard stops may be used in several different numbers, positions, and configurations in repair or modification systems. Hard stops may be installed by determining location on an outside of a restrainer bracket for the hard stop, securing the hard stop at the location, and biasing the hard stop between two components at the location.

Abstract: A method and apparatus for securely fastening a pipe collar or a bracket to a riser pipe of a boiling water reactor (BWR) jet pump assembly. A pipe plug assembly includes an angled pipe plug that acts as a wedge to expand a bushing assembly as the pipe plug is drawn into the overall pipe plug assembly. Expansion of the bushing assembly allows a tight tolerance to exist between an outer diameter of the pipe plug and an inner diameter of the collar/bracket and riser pipe. Expansion of the bushing assembly allows a straight hole to be match drilled into the collar/bracket and riser pipe, thereby avoiding a more complicated tapered hole to be drilled into the collar/bracket and riser pipe. An ensuing tight fit between the pipe plug assembly, the collar/bracket and the riser pipe mitigates vibration of components and minimizes leakage to acceptable levels for use in the flooded environment of the annulus region where the jet pump assembly exists in the BWR.

Abstract: A method and apparatus for repairing and/or reinforcing a Boiling Water Reactor (BWR) jet pump riser pipe. The repair includes attaching two collars to the riser pipe using match drilling to drill holes through the collars and the riser pipe and plugging the holes with expandable plugs. Support columns are attached to the collars. Brace supports are slideably attached to the support columns. Gaps between each brace support and its respective collar are then narrowed as ratchet bolts may apply a force that pulls downward on an upper collar and pulls upward on a lower collar, thereby exerting a compression force on the riser pipe. A clamp assembly may also be located between the two collars that applies a hoop force on the riser pipe.

Abstract: Disclosed are various wedges that may be used in a restrainer bracket of a jet pump assembly. The jet pump assembly may include a restrainer bracket having an upper bracket and a lower bracket connected to an inlet mixer. A wedge may be provided between the upper bracket and the lower bracket and a wedge rod may pass through a slotted hole of the wedge. Ends of the wedge rod may be attached to the upper and lower brackets. The restrainer bracket may further include a yolk-like member which surrounds the inlet mixer and is connected to a riser pipe. The wedge may include an inclined surface which is configured to engage with a restrainer bracket pad of the yolk-like member. The wedges may further include inner curved surfaces which contact the wedge rod and the inner curved surfaces may be part of an insert that may be inserted in the wedge.

Abstract: A method and apparatus for providing a Boiling Water Reactor (BWR) jet pump slip joint internal seal in the interface between an inlet mixer and a diffuser of a jet pump assembly. The internal seal provides an effective means of mitigating leakage and slip joint flow induced vibration (FIV) between the inlet mixer and diffuser to reduce damage to many of the jet pump assembly components that may otherwise be damaged by FIV. A metallic seal of the slip joint internal seal flares out to conform the internal seal to a range of gap sizes, and may be compressed or spring back to nominal dimensions as thermal expansion and contraction occurs. The internal seal is also self-expanding/self-tightening, as the internal seal flares further outward as a result of the internal pressure caused by flowing fluids in an operating jet pump assembly.

Abstract: Disclosed are various torsional restraint systems for torsionally restraining a jet pump assembly, wherein the jet pump assembly includes a riser pipe, a transition assembly on the riser pipe, and a restrainer bracket connecting a first and a second inlet mixer to the riser pipe. The torsional restraint system includes a first contact member operatively attached to a side of the jet pump assembly and a second contact member operatively attached to the side of the jet pump assembly and disposed from the first contact member such that the first and second contact members restrain the riser pipe from rotating about a centerline of the riser pipe.

Abstract: An embodiment of the present invention provides an apparatus and system for repairing and/or maintaining a position of a first component in relation to a second component. The first and second components may be located within a reactor pressure vessel of a nuclear powerplant. The apparatus and system may attach at least one bearing plate to a horizontal surface of the first component. The apparatus and system includes structure to apply a pre-load to the first component. This may assist in maintaining the position of the first component relative to the second component.