Creep-Fatigue Life Prediction and Reliability Analysis of the Solar Tower Molten Salt Receiver Tubes

In concentrated solar power (CSP) systems, receiver tubes experience creep-fatigue deformation under actual high-temperature operating conditions. This deformation arises from constant static stress or pressure, diurnal cycles, and frequent thermal shocks. This study evaluates the creep-fatigue reliability of receiver tubes during service life by randomizing parameters such as tube dimensions, applied loads, and the creep-fatigue life model. A reliability assessment method for creep-fatigue in receiver tubes is proposed based on the stress-strength interference theory. A computational method for determining the creep-fatigue life of receiver tubes was developed. Based on a normal distribution model of factors such as tube dimensions, applied loads, and creep-fatigue life model parameters, Latin hypercube sampling was employed to perform statistical sampling, resulting in a distribution model for the creep-fatigue life of receiver tubes. Furthermore, a creep-fatigue reliability assessment model was established using stress-strength interference theory. A case study was conducted for a specific receiver tube, with results indicating a maximum equivalent stress of 156.65 MPa and an estimated creep-fatigue life of approximately 7.49 years. The failure probability of the receiver tube was found to be 0.18 after 5 years of service and 0.82 after 10 years of service.