Fluid-Thermal-Mechanical Coupling Analysis of the Reactor Vessel of Natural Circulation Lead-Cooled Fast Reactor SNCLFR-100

Abstract Lead-based reactors mostly adopt integrated pool structures to simplify the design of reactor and have high inherent safety. As an important safety facility in the primary circuit, the reliability of the reactor vessel is critical for the safe operation of the whole reactor. The reactor vessel of natural circulation lead-cooled fast reactor SNCLFR-100 was taken as the object, and the corresponding simplified model was established. Based on ANSYS, the fluid-thermal-mechanical coupling analysis was carried out under the steady-state to study the influence of flow field and temperature field on the reactor vessel, and to reveal the distribution law of key thermal and mechanical parameters under the steady-state operation in this paper. The results of mechanical calculations were evaluated based on American society of Mechanical Engineers (ASME) standards, and the preliminary design scheme of reactor solid structure was optimized. The results showed that the stress evaluation results of the SNCLFR-100 reactor vessel meet the requirements of ASME standards in steady-state operation conditions. After optimizing the original solid structure, the stress evaluation results show that the maximum stress value was reduced by 43.3%, and the stress concentration was obviously suppressed, which indicates that the reactor container has a higher safety margin under the optimization scheme. The Steady-state calculation based on normal operation conditions provides a certain research basis for the subsequent transient calculation under accident conditions.