Ultrasonic test procedure for evaluating fuel clad endcap weld joints of PHWRs

Abstract

This paper describes the application of ultrasonic test method and digital signal analysis techniques for the detection of fine defects of {approx_equal}10 percent of wall thickness in resistance welded endcap-clad tube joints of fuel elements used in pressurized heavy water reactors (PHWRs). Standardization of test methodology was carried out using reference defects made on inner an outer surface of the weld region and subsequently, testing wa carried out on a number of endcap weld joint suspected to have natural defects which were rejected in the helium leak testing. The results obtained were further validated by destructive metallography, thereby confirming the sensitivity and reliability of the developed test methodology.