Effect of power output difference on natural convection in heat pipe micro-MSR

Heat pipe molten salt reactors are well-suited for deep space and deep-sea exploration due to their compactness, safety, and efficient heat transfer. Based on a designed 50 kWt micro molten salt reactor (micro-MSR), an experimental prototype was developed to study its key technologies. The prototype differs from the conceptual reactor, necessitating numerical simulations to validate the experimental setup. This study utilizes numerical simulation methods to emulate the prototype's constant-temperature control functionality by varying thermal boundary conditions, thereby modulating the thermal power output. Through this approach, comprehensive performance data across multiple operating conditions were obtained, enabling systematic analysis of the temperature and flow field distribution characteristics within the prototype's reactor core. The simulation results validate the safety and reliability of the experimental prototype's design. Key findings include: 1) Core develops annular convection along concentric rings driven by thermal density gradients. 2) Molten salt temperature increases vertically with elevation, forming localized hotspots in the upper core region. The results provide critical theoretical references for understanding molten salt thermal-hydraulic behavior in the prototype, while offering fundamental support for subsequent experimental investigations using this test facility.