Start-Up Simulation of the Improved TOPAZ-II Space Power System

An system analysis code coupled with the heat pipe model is developed to analyze the thermal-hydraulic characteristics of the improved TOPAZ-II space reactor power system with a heat pipe radiator. The core thermal-hydraulic model, neutron physics model, and the coolant loop components models (including pump, volume accumulator, pipes and plenums) are established. The designed heat pipe radiator, which replaces the original coolant loop radiator, is also modeled, including the two-dimensional heat pipe analysis model, the fin model and the coolant transport duct model. The start-up procedure of the improved TOPAZ-II system are calculated. The results show that the code can be used to obtained the thermal characteristics of the system start-up process.