원전 배관의 두께 측정 데이터에 대한 신뢰도 분석 방법 및 적용

Abstract

Pipe wall-thinning by flow-accelerated corrosion and various types of erosion is significant damage in secondarysystem piping of nuclear power plants(NPPs). All NPPs in Korea have management programs to ensurepipe integrity from degradation mechanisms. Ultrasonic test(UT) is widely used for pipe wall thicknessmeasurement. Numerous UT measurements have been performed during scheduled outages. Wall-thinningrates are determined conservatively according to several evaluation methods developed by Electric PowerResearch Institute(EPRI). The issue of reliability caused by measurement error should be considered inthe process of evaluation. The reliability analysis method was developed for single and multiple measurementdata in the previous researches. This paper describes the application results of reliability analysis methodto real measurement data during scheduled outage and proved its benefits.