Long-range guided wave inspection of delayed neutron tubes used in heavy water reactors by a magnetostrictive transducer

Delayed neutron (DN) tubes in the pressurized heavy water reactors (PHWRs) are susceptible to a possible leakage during operation because of fretting wear. Their geometrical complexity and inaccessibility due to a high radiation field, however, renders it difficult to inspect them by a conventional ultrasonic method. A long-range guided ultrasonic inspection, thus, will be only an option to be applied during a overhaul period. In this paper, a magnetostrictive transducer was used for generating and detecting the guided waves for the DN tubes. This study, for the first time, investigated the applicability of a long-rang guided ultrasonic method to the detection of artificial notches even in the presence of various foreign objects