Study of a stainless steel porous membrane for recovering tritium from Pb-Li alloys: Assessment of mass transfer coefficient

摘要

The eutectic Pb-Li alloy is used as liquid breeding blanket material in the concept design of future fusion nuclear reactors where the effective extraction of generated tritium is an important unit operation of the fusion fuel cycle. In this context, the adoption of porous stainless steel tubes working as Membrane Gas-Liquid Contactors (MGLCs) has been proposed for recovering hydrogen isotopes from liquid Pb-Li alloys. Taking into account the results achieved in a previous experimental campaign carried out at 370 degrees C, the hydrogen mass transfer coefficient has been evaluated and compared with data available in literature.The present study reveals that hydrogen extraction consists of diverse steps, although it is mainly controlled by recombination of hydrogen atoms and their desorption from the gas-liquid interface. The overall permeation exhibits mass transfer resistance values in the range 10(-7) - 10(-)(6) m(2) s Pa mol(-1), while hydrogen transport through the MGLC pores takes place with mass transfer resistances significantly smaller (around 10(-4) m(2) s Pa mol(-1)). These results make the use of MGLCs very promising for an effective extraction of tritium from liquid breeders in fusion reactors.