Effects of Bayonet Tube Leak on the Heat Transfer Characteristics of Fuel Drain System in Molten Salt Reactor

Abstract  [Background]: The liquid-fueled molten salt reactor is one of the candidates for the Generation IV reactor technologies, and the fuel drain system is a special safety design.  [Purpose]: This study takes the fuel drain system of Molten Salt Reactor Experiment (MSRE) as the research object and investigates the influence of inner barrier leak of one heat exchange element on heat transfer characteristic. [Methods]: First, computational fluid dynamics simulation methods were employed to construct heat transfer and multiphase flow models to analyze the heat transfer and flow phenomena under normal operation and bayonet tube leak scenario.

Then sensitivity analyzes of key influencing parameters, such as the leak size (3 mm to 8 mm), leak location (10 mm to 1500 mm above the lower end of the heat exchange element ) and pressure in the annular gas space (ranging from -13788 Pa to 13788 Pa) , were carried out.  [Results]: The analysis results show that 18.4% of cooling water flows out from the leak location through the annular gas space when bayonet tube leak occurs and the power of one single heat exchange element increases to 29.434 kW.