CAPTURE OF KRYPTON BY CRYOGENIC DISTILLATION
Radioactive krypton-85 is liberated into the off- gases during the reprocessing of spent nuclear fuel (chop and leach process). Krypton recovery by cryogenic distillation in presence of oxygen was investigated. Both oxygen and ozone behaviour in the cryodistillation unit were observed. The ozone decay in the rectification column was studied in absence and in presence of a radiation (500 Ci thulium-170) source. Experiments with different oxygen concentrations up to 21% volume in the feed gas showed oxygen enrichment up to 85% volume in a zone between the krypton layer and the entrance of the rectification column. On the other hand, ozone accumulates in the bottom liquid. Its decay was measured without the radiation source: a decay from 0.9% volume to 0.45% took 30 days; the decay rate decreased with decreasing ozone concentrations; when measured with the 500 Ci thulium-170, a constant decay rate of 0.24% volume per day was observed. Finally, a demonstration run with 100 Ci krypton-85 was performed in the cryodistillation unit, with air as feed gas. It was fed at a concentration of 30 mCi.h**-1 until the total krypton inventory of the rectification column amounted to 40-45 Ci. The active run lasted 900 hours, no operational problems were encountered.
Bibliographic Reference: EUR 10515 EN (1986) MF, 31 P., BFR 150, BLOW-UP COPY BFR 200, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989125001500 / Last updated on: 1987-01-01
Available languages: en