The processes described in Sec. 4.6 are, in principle, applicable to off-gases from LMFBR reprocessing plants. The problem is the greater iodine activity per ton of fuel processed. This is due to the 60 percent higher specific activity of iodine for 150-day cooled LMFBR fuel compared with similar LWR fuel noted in Table 10.20 and the incentive to reprocess LMFBR fuel with shorter cooling. Oak Ridge National Laboratory has estimated that if LMFBR fuel were to be reprocessed only 30 days after irradiation, an iodine retention factor as high as 1010 would be required. This seems completely unattainable. However, some improvement over the retention factor of 102 (99 percent retention), feasible with the technology described in Sec. 4.6, would be possible if iodine could be stripped more completely from the dissolver solution. Retention factors of 104 or better have been reported for individual silver-zeolite absorbers.