The control rod channel tubes of the Thorium Molten Salt Reactor (TMSR) are typical high-temperature, thin-walled, long cylindrical shells designed to withstand external pressure, with creep buckling as its primary failure mode.

This study aims to use numerical simulation methods to study the creep buckling instability behavior of control rod channel tubes at the elevated temperatures.

Firstly, the Norton creep model and material parameters for the UNS N10003 alloy was obtained on the basis of the high-temperature creep test data. Furthermore, finite element analysis software ABAQUS was employed to assess eigenvalue buckling and creep buckling for TMSR control rod channel tubes. Sensitivity analysis was conducted on the key factors causing buckling instability, and an empirical formula for creep buckling life was obtained.

The analysis results reveal that temperature, pressure, and structural dimensions significantly influence the tube's creep buckling life, and the derived empirical formulas can be used to verify the durability of the tubes. To ensure a design life of 30 a for the casing at 700 ℃, the tube height needs to be controlled below 3 m. If the design life is 10 a, the tube height can be increased to 6 m.

This study 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 thin-walled structures.