Mass Transfer Operational Units Applied to the Liquid Breeding Material of Fusion Reactors for Tritium Recovery

The extraction of tritium from the liquid alloy 17Li83Pb has been examined taking into consideration the equations related to the design of “droplet spray” and “bubble” extractors in order to verify which are the higher tritium recovery efficiencies which can be realized so as to minimize the permeation of tritium into the water of the cooling system. As far as the droplet spray unit is concerned, the tritium extraction efficiency has been correlated to tritium pressure in the extractor, to the droplet radius and to the residence time of the droplets in the extractor. For the tritium desorption from the alloy, flowing countercurrent to a helium stream in a bubble extractor, the axial dispersion in the liquid and gaseous phases and the effects of gas phase expansion caused by reduced hydrostatic head in the extractor are taken into account. From the results of this study, both the bubble and spray droplet extractors seem to be very appropriate units for tritium recovery from the alloy. Moreover, in order to reach high extraction efficiencies for reducing the tritium permeation to the water cooling system, the spray droplet extractor appears more suitable.