Recovery of rare gases partic. xenon from air - esp. gases recovered during treatment of irradiated fuel elements

摘要

Treatment of a mixture of air and rare gases, esp. xenon and krypton, at least partly radioactive, partic. gaseous effluents from the treatment of irradiated nuclear fuels esp. the stages of sectioning the fuel rods and dissolving in nitric acid comprises incorporating a stage in which the rare gases are concentrated in soln. in liquid oxygen by cryogenic distillation of light gases, principally nitrogen from the liquefied mixt. In particular, the process includes a stage of separation of the rare gases by catalytic combustion of the oxygen with hydrogen and elimination of water followed by a cryogenic distillation of other rare gases to recover the xenon. Compared with the known process in which the xenon and krypton are concentrated in liquid nitrogen, the problem of the formation of crystalline xenon in the distillation column due to its low solubility in liquid nitrogen, is eliminated.