Estimation of the Probability Distribution of Flow-accelerated Corrosion Rate in Feeder Pipes

Abstract

Flow-accelerated corrosion (FAC) is a life limiting factor for the feeder pipes of the primary heat transport system (PHTS) of CANDU reactors. The pipe wall thinning caused by FAC is monitored by carrying out periodic inspections during plant outages to ensure the fitness-for-service of the feeder piping system. To accurately predict the time of replacement of various components in the feeder piping system, estimation of the FAC thinning rate is necessary. This paper presents a simple and intuitive simulation-based approach called approximate Bayesian computation (ABC) to estimate the FAC thinning rates in feeder pipes from noisy inspection data. The application of the proposed approach is illustrated through a practical data-based example.