Statistical analysis results of performance demonstration for piping welds

Abstract

A performance demonstration programme has been implemented by the Institute of Nuclear Energy Research since 2002. This programme followed the criteria of the ASME Boiler and Pressure Vessel Code Section XI, Appendix VIII to prepare demonstration sessions in Taiwan and has gained meaningful data during the past 13 years. In this paper, historical demonstration results on the similar metal pipe welds are analyzed and the statistical data show the overall qualification rate, accuracy rate, and detection rate are about 63%, 93%, and 90% respectively. The length sizing errors depend on the piping material and flaw orientation, and the average relative error of qualified examinees is 58.8%±4.2%. This programme can provide a good screening function for ultrasonic inspection personnel, and the statistical results can also provide both regulatory authorities and utilities with a conservative evaluation of the confidence level of realistic ultrasonic testing results in nuclear power plants.

Statistical analysis results of performance demonstration for piping welds

“…The first developed programme item, which is for inspecting service-induced flaws in similar metal pipe welds, has now been implemented for more than 13 years. The first two years experience of this program was presented in INSIGHT [1] . In this paper, the progressively accumulated data of the period 2002-2015 are analyzed and the improvement in the domestic UT capability is evaluated.…”