Methods and apparatus for repairing a cracked jet pump riser in a boiling water reactor utilizing a spacer camp

摘要

A method for repairing cracked jet pump riser assemblies in a boiling water reactor utilizes a spacer clamp and a seal collar. The spacer clamp is secured to the riser assembly to limit horizontal displacement of the riser assembly, and the seal collar is secured around the weld joining the riser elbow and the thermal sleeve to limit leakage from the weld over a predetermined range of horizontal displacement defined by the spacer clamp. A method for repairing a circumferential weld connecting an elbow of a jet pump riser assembly with a thermal sleeve involves positioning the weld within a seal collar and securing the seal collar on the jet pump riser assembly so that seals of the seal collar sealingly contact the elbow and the thermal sleeve, respectively, circumferentially on opposite sides of the weld. A spacer clamp for limiting horizontal displacement between a shroud and a jet pump riser assembly includes inboard and outboard clamp members for seating against the pipe, with the inboard clamp member establishing a gap with the shroud corresponding to a predetermined amount of horizontal displacement allowed between the shroud and the pipe. A seal collar for limiting leakage from a crack in piping of a boiling water reactor includes a pair of hinged jaw members movable between an open position for receiving a pipe therebetween and a closed position encircling the pipe at the location of the crack, and pairs of seals disposed along inner surfaces of the jaw members, respectively, forced into sealing, circumferential contact with the pipe on opposite sides of the crack to limit leakage from the crack.