Fatigue life prediction and reliability assessment of fusion reactor liquid breeding blankets based on a stress-coupled corrosion model

Abstract The liquid breeding blanket is a critical component of magnetically confined fusion reactors, with corrosion fatigue induced by pulsed operation and the high-temperature lead-lithium environment constituting a primary failure mechanism. This study proposes a stress-coupled corrosion-fatigue life prediction and reliability evaluation framework applicable to fusion liquid breeding blankets. A unified corrosion-fatigue damage model was developed for reduced activation ferritic-martensitic (RAFM) steel in high-temperature lead-lithium environments, explicitly incorporating the effects of temperature, flow velocity, stress, and damage evolution. Bayesian statistical methods were employed to estimate the posterior distributions of key model parameters from experimental data, thereby quantifying parameter uncertainty. For a typical outboard equatorial module of the China Fusion Engineering Test Reactor (CFETR) supercritical CO 2 -cooled lead-lithium (COOL) blanket, the life distribution and reliability metrics of the blanket were evaluated by integrating the corrosion-fatigue damage model, COOL blanket operational loads, and Monte Carlo simulations. Computational results indicate an average failure time of 8.25 years for the blanket, with a 90 % confidence interval ranging from 4.94 to 12.72 years. The influence of material-environmental parameters was assessed through sensitivity analysis. The results can provide essential input parameters for Reliability, Availability, Maintainability, and Inspectability (RAMI) studies of blankets, offering insights to potentially improve CFETR duty cycle.