Method and apparatus for remote ultrasonic inspection of core spray

Abstract

A method and an apparatus for in situ ultrasonic inspection of the core spray T-box to thermal sleeve attachment weld and the core spray T-box to cover plate attachment weld in BWRs. The apparatus incorporates a stationary clamping mechanism and sliding and rotational mechanisms which are operated remotely to scan the transducer over the T-box welds and heat-affected zones thereof. The T-box weld inspection tool comprises the following assemblies: clamping jaws for clamping the tool onto the T-box arms in response to activation of a pair of pneumatic cylinders; a side slide stage having a transducer carriage which is slidable in parallel with the centerline axis of the thermal sleeve in response to activation of a first drive motor; a radial face stage having a transducer carriage which is slidable in a direction perpendicular to the centerline axis of the thermal sleeve in response to activation of a second drive motor; and a rotation stage which rotatably supports both the side slide stage and the radial face stage for rotation about the centerline axis of the thermal sleeve in response to activation of third and fourth drive motors, respectively. The transducers carried on the radial face stage are used to interrogate the T-box to cover plate attachment weld; the transducers carried on the side slide stage are used to interrogate both the T-box to cover plate and the T-box to thermal sleeve attachment welds.