Experimental Study of a Gas Separator for MSR Gas Removal System

Abstract

An independent gas removal system was firstly put up by Oak Ridge National Laboratory (ORNL) for Molten Salt Breeder Reactor (MSBR) to remove fission gas such as Xenon etc. from molten salt (LiF–BeF–UF), where the gas separator is a key equipment for which high separation efficiency and low pressure drop are required. Swirl vanes and recovery vanes are installed around the inlet and outlet of the gas separator. With reference to the design of ORNL, a new gas separator was designed for a conceptual design of a small molten salt research reactor. An experimental loop was also fabricated to test the local pressure drop and separation efficiency of the new designed gas separator using of water and air as working fluid. The separation efficiency is measured by comparing the gas flow rate from the bubble generator and that at the outlet of the separator using of high speed video camera. The tests were conducted with the water flow rates covering 10–30 m3/h and an average void fraction of 0.3%. Besides, the shape of gas cores is found necessary to estimate the working performance of gas separators. High separation efficiency comes with a stable and straight gas core, and the gas will be taken off from two ends of the gas separator. What’s more, the result shows that low concentration of gas does not increase the pressure drop compared with the condition of liquid only, except when it exceeds a certain level. Finally, local flow resistance of the gas separator was also obtained under low gas concentration condition, showing that the resistance factor is nearly unvaried with a value of 5.