Advances in the Application of Remote Weld Repairs

Weld repair sites in nuclear systems are very often located in high radiation areas in difficult to reach sites. Additionally it is usually a pre-requisite to shut down the reactor while the repair is performed, ideally during a scheduled maintenance outage. To minimize the risk of an extended outage it is of paramount importance to ensure the repair time is optimized and the technique is reliable. Technical solutions to complex remote weld repairs are rarely available “off the shelf”. While some commercially available products can be adapted to suit an application, the constraints of space, distance and radiation usually require novel and unique designs involving a variety of engineering skills. Of equal importance to the weld repair is the requirement to perform pre and post repair nondestructive examinations (NDE). The application of ultrasonic, eddy current and liquid penetrate examinations requires a similar level of engineering. This paper outlines some of the welding and NDE techniques developed to address unique repairs to nuclear systems.