Tritium recovery from fusion blankets using solid lithium compounds. II. Experiments on tritium removal and absorption

It was shown experimentally that tritium can be easily removed from certain solid lithium compounds that have been proposed as components of CTR breeder blankets. The compounds tested were LiAl, Li7Pb2, LiAlO2 and Li2SiO3 in granular or powder form; the procedure was to pass a stream of helium through a bed of material maintained at a temperature in the range 400-6000C. As the tritium, which had been previously generated in the materials by exposure to thermal neutrons, diffused out and was carried away, its concentration was continuously monitored by radioactive assay of the gas stream. From the data, it was possible to calculate average lifetimes of tritium in a continuously extracted breeder blanket. Lifetimes of a few hours were found for LiAl and Li7Pb2 at 400-5000, LiAlO2 at 6000 and Li2SiO3 at 500-6000. The extraction kinetics of LiAlO2 were consistent with a diffusion-controlled process, and it was possible to calculate diffusion coefficients from the data. A series of hydride-forming metals were tested for their ability to trap out tritium from dilute helium streams and later release it on heating. Vanadium appears to be satisfactory