Simulation and life evaluation of creep crack propagation in GH3535 alloy based on fracture mechanics

<bold>Background</bold>The life assessment of high-temperature components with defects in the thorium molten salt reactor (TMSR), which is one of the fourth-generation reactors, is a crucial part of structural integrity assessment.<bold>Purpose</bold>This study aims to simulate the creep crack propagation CCP of compact tensile (C(T)) specimens and to carry out a life assessment of these specimens, providing engineering guidance for life prediction of defect structures at elevated temperatures in Thorium Molten Salt Reactor (TMSR).<bold>Methods</bold>The CCP of C(T) specimens was firstly simulated by using the Contour integral evaluation method in finite element analysis (FEA) software Abaqus. Subsequently, based on time-dependent creep fracture mechanics, an automated analysis program was written in Python to calculate the creep fracture parameter <italic>C</italic>*. Then, a time-dependent failure assessment diagram (TDFAD) for GH3535 alloy was established, and the stress intensity factor <italic>K</italic> and reference stress <italic>σ</italic>_ref were extracted and calculated from FEA results. Finally, a life assessment of C(T) specimens was carried out.<bold>Results</bold>The comparison between experimental data and simulation results by using the creep fracture parameter <italic>C</italic>* demonstrates that the FEA method can effectively simulate the crack propagation in the specimens. The TDFAD of GH3535, combined with FEA, visually presents the process of crack propagation leading up to equipment failure.<bold>Conclusions</bold>Results of this study explain the behavior of GH3535 alloy's creep cracks and provide engineering guidance for life prediction of defect structures at elevated temperatures in TMSR, ensuring the safety and reliability of the reactor's high-temperature components. The life assessment of high-temperature components with defects in the TMSR is a crucial part of structural integrity assessment.