Probabilistic residual life assessment against thermal fatigue and creep

This study focuses on the residual life assessment of nuclear power plant components carrying high temperature fluids, which exhibit random temporal fluctuations about a mean value. The primary mechanisms of damage in the components are due to thermal fatigue and creep. First, based on available data, a stochastic model for the random temporal fluctuations is developed. The thermal stresses generated due to the loadings are multiaxial in nature and are random processes in time. The von Mises stress, obtained as a nonlinear combination of the components of the stress tensor, is considered for estimating the expected fatigue damage. Analytical expressions are developed for estimating the expected fatigue damage. For estimating the expected creep damage, it has been shown that even though creep growth is a slow process and the temporal fluctuations do not appear in the growth trajectories, random variable models are not sufficient. Finally, estimates of the failure probability are obtained by considering different models for the creep-fatigue interaction effects. This study is currently in progress. © 2013 Taylor & Francis Group, London.