[en] The coupling of industrial gas processing and cryogenic technology yields an approach for the efficient and reliable recovery of the radioactive fission product noble gases (especially ⁸⁵Kr) from the off-gas of LWR and LMFBR fuel reprocessing plants. The fundamental processing step that is employed to separate the noble gases is the cryogenic or low-temperature liquefaction and distillation of the off-gas. The residual gas after the removal of the noble gases is rejected to the atmosphere through the plant stack as a decontaminated waste stream. System krypton recovery factors of greater than 99.9 percent can be achieved while minimizing the required krypton storage. All elements of the process design utilize proven technology which has been commercially demonstrated