Creep-Buckling Instability Analysis of TMSR Control Rod Channel Tubes

[Background] The control rod channel tubes of the Thorium Molten Salt Reactor (TMSR) are typical high-temperature, thin-walled, long cylindrical shell designed to withstand external pressure, with creep buckling as its primary failure mode. [Purpose] This article aims to use numerical simulation methods to study the creep buckling instability behavior of control rod channel tubes at the elevated temperatures. [Methods] This study derived the Norton creep model and material parameters for the UNS N10003 alloy based on the high-temperature creep test data. Furthermore, finite element analysis was employed to assess eigenvalue buckling and perform numerical simulations of creep buckling in TMSR control rod channel tubes. [Results] A parametric sensitivity analysis was conducted on critical factors contributing to buckling instability, and the empirical formulas were obtained for verifying durability. The findings reveal that temperature, pressure, and structural dimensions (inner diameter, wall thickness, height) significantly affect the tube's creep buckling life. [Conclusions] This research offers engineering guidance for the stability design of TMSR control rod channel tubes and high-temperature structures under complex conditions, and it also serves as a basis for predicting the creep buckling lifespan of other high-temperature reactor thin-walled structures.