Advanced Eddy Current Probes for Nondestructive Examination of Dry Storage Canisters

摘要

This paper presents on overview of "advanced" eddy current probe instrumentation and concepts for application to nondestructive sizing of cracks in containers for dry storage of used nuclear fuel. This is an extension of current work focused on developing a multi-frequency technique for crack sizing using a "simple" single coil, absolute eddy current probe. The advanced instrumentation overview considers alternative field pick-up sensors such as Hall effect sensors and giant magnetoresistive sensors that may ultimately enable improved performance through better spatial resolution, field sensitivity, and/or sensitivity to field direction. The overview includes a summary of environmental limitations (i.e., temperature and radiation) of these sensors with respect to performance. In addition, this overview considers some advanced concepts, such as pulsed eddy current concepts, and concepts with various sensor configurations. Configurations are reviewed that have the strongest relevance to the application of crack monitoring in dry storage containers and their strengths are highlighted.