Abstract：The tritium fuel cycle of the liquid metal blanket is a core technology for the normal operation of a fusion reactor or a fusion-fission hybrid reactor. The tritium fuel circulation system consists of the tritium purification, the tritium extraction, the tritium storage, the tritium measurement, the helium/water cooling and the tritium recovery subsystem. The liquid metal bubbler located between the blanket main circuit and the tritium extraction system is an indispensable key component for its important functions in tritium monitoring and removal. However, the development of a bubbler is difficult as the solubility of hydrogen isotopes in liquid lithium lead is very low and the liquid alloy has some unique characteristics in high temperature, with respect to an effective design and building of Liquid Lithium Lead Bubbler (LLLB) for the Tritium Breeding Module (TBM) of fusion reactor. An algebraic model to describe the gas holdup characterization, the bubbler diameter and the size distribution is developed under the assumptions that the gas phase is non-Newtonian and there is no frictional force between gas and liquid phases. Simulation results show that bubbles would break up much faster than while being coalesced under low gas velocity. In LLLB, the breakage is a dominant feature for bubbles after they leave the orifice. Initial bubbles formed over the orifice are mostly larger than the largest stable bubble. They would break up quickly and their sizes are reduced to below the maximum diameter ds of stable bubbles. Moreover, the gas-liquid surface area would be increased even though the gas holdup does not change significantly. A high mass transfer area could be obtained by injecting more small initial bubbles with diameters under ds.
2010, Vol. 28 
