Papers by Author: R. Bruce Thompson

Abstract: Ultrasonic phased array inspection has been paid a great attention in ultrasonic nondestructive evaluation since it can provide a benefit of focusing and/or steering ultrasonic beams. A time reversal technique is claimed to be very robust to focus beams through inhomogeneous media, using the phased array transducers. In this paper, the performance and limitations of a D.O.R.T. method, which is one of the time reversal techniques, is considered based on the experimental studies. In addition, a variation of the D.O.R.T, namely a pre-focused D.O.R.T., is proposed in order to overcome the limitations of the current D.O.R.T. method. The results of the newly proposed method are compared to those obtained by conventional focusing methods.

Abstract: This paper considers the use of on-line structural health monitoring in advanced nuclear power systems such as IRIS. The motivation for the on-line health monitoring is to prevent routine maintenance from interrupting long-term continuous reactor operation. However, the outcome of the on-line monitoring implementation has a broader impact, and amounts to a paradigm shift in maintenance strategy from outage-based maintenance to continuous real-time monitoring of operational and structural integrity. Indeed, on-line health monitoring data will provide a foundation for diagnostics and prognostics (i.e., predictive) capabilities that will detect component degradation prior to failure, thus allowing for proactive rather than reactive maintenance strategies. Specifically, this paper briefly reports on our studies on (1) on-line monitoring strategy and its benefits, (2) candidate reactor components where on-line monitoring provides maximum benefits, (3) applicable on-line NDE sensor methodologies and conceptual sensor designs, and (4) model-based sensor performance estimations.