Failure probabilistic analysis of steam generator heat-transfer tubing with pitting corrosion

Pitting corrosion damages seriously steam generator (SG) heat-transfer tubing of nuclear power plants. To estimate accumulative failure probability of the SG heat-transfer tubing, a failure probabilistic analysis method with pitting corrosion of stochastic processes is proposed in this paper. Pitting corrosion can be considered as a combination process of pit initiation and growth. The pit generation process is built as a non-homogenous Poisson process. The pit growth process is modeled by a stationary gamma process. A cumulative failure probability model is derived from the stationary gamma process. The proposed model is evaluated with the maximum likelihood estimation method according to the experiment data. Finally, Monte Carlo method is applied to simulate the cumulative failure probability model. The results illustrated that the proposed method is feasible and practical to estimate the accumulative failure probability of the SG heat-transfer tubing.