Predicting distributions of wear sites on shell wall of feedwater heater in nuclear power plant using two phase models

Abstract

Severe wall thinning may cause a leak on the feedwater heaters (FWHs) shell wall, which could result in the nuclear power plant derating or shutdown, even personal fatalities. This wall thinning of FWHs shell is essentially engendered by droplet impingement wear, which is strongly related to the two phase flow characteristics within the shell side. In this paper, two phase models are proposed to investigate the characteristics of droplet flow and predict the distributions of impingement wear sites for the FWHs. These models include the Eulerian/Lagrangian droplet type two phase models and the droplet impingement wear model. Based on the simulation results, the flow models can reasonably capture the three dimensional distribution of droplet flow and its rebound characteristics within the FWHs shell side. Coupled with these flow characteristics, an appropriate indicator, derived from the droplet impingement wear model, is used to predict the severe wear sites on the FWHs shell wall. The predicted wear sites agree well with the plant measured data for the selected nuclear power plant. The unsymmetrical distribution patterns of wear sites are also precisely captured. These correspondences show that the two phase models presented herein can be used to investigate the flow characteristics and impingement wear for FWHs in the nuclear power plant.