A probabilistic model of wall thinning in CANDU feeders due to flow-accelerated corrosion

Wall thinning due to flow-accelerated corrosion (FAC) is a pervasive form of degradation in feeder pipes of the primary heat transport system of CANDU reactors. Prediction of the end-of-life of a feeder from wall thickness measurement data is confounded by the sampling and temporal uncertainties associated with the FAC degradation phenomenon. This paper presents a probabilistic model of wall thinning due to FAC, and calibrates it with a set of feeder wall thickness measurements obtained from a CANDU plant. The proposed model derives the feeder lifetime distribution, which is useful in developing optimum strategies for life-cycle management of the feeder system.