Ultrasonic Phased Array Technique for Accurate Flaw Sizing in Dissimilar Metal Welds

76289-The implementation of recent ASME standards for nuclear power plant safety have clearly demonstrated the inadequacies of current technologies in sizing the through-wall extension of flaws located in dissimilar metal (DM) piping welds. The lack of any qualified manual volumetric inspection technique from the outer surface of the pipe provides utilities with few options when a flaw is detected. This problem has additional significance because the discovery of cracking in DM welds is becoming more common. This project will develop and demonstrate a unique phased array transducer design and data collection method that will significantly increase the accuracy and repeatability of the through-wall sizing of cracks. In Phase I, the phased array system will be tested both on machined reflectors and on dissimilar weld samples with fully characterized cracks. The samples will be provided by the Electric Power Research Institute (EPRI). Commercial Applications and Other Benefits as described by the awardee: Once the system passes through the ASME qualification process, an immediate market should develop in the nuclear industry. This technique could also be expanded for use in other challenging applications such as the inspection of cast stainless steel.