Field Experiences with Multifrequency-Multiparameter Eddy-Current Technology

摘要

A multifrequency/multiparameter eddy current system has been assembled for the inservice inspection of pressurized water reactor steam generator tubing. Five steam generators were inspected for a total data base of approximately 11,000 tubes. Based on a comparison with conventional single frequency inspection methods, multifrequency/multiparameter eddy current technology offers significant improvements. Multifrequency eddy current, with its multiple frequency coil excitation, can offer benefits in reducing in-containment data acquisition time by the performance of parallel tube tests; in addition the resulting broad spectrum data base is useful for the analysis of complex or non-unique signals which can arise during a steam generator inspection. Multiparameter eddy current offers an approach for the real-time suppression of extraneous variables such as support plates/tube sheet, ID noise and denting. With appropriate mixing/basis frequency combinations, tube degradation in the presence of the extraneous variables can be more reliably detected and characterized. (ERA citation 07:053737)