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Title: Carbon dioxide-krypton separation and radon removal from nuclear-fuel-reprocessing off-gas streams

Conference ·
OSTI ID:5363147

General Atomic Company (GA) is conducting pilot-plant-scale tests that simulate the treatment of radioactive and other noxious volatile and gaseous constituents of off-gas streams from nuclear reprocessing plants. This paper reports the results of engineering-scale tests performed on the CO/sub 2//krypton separation and radon holdup/decay subsystems of the GA integrated off-gas treatment system. Separation of CO/sub 2/ from krypton-containing gas streams is necessary to facilitate subsequent waste processing and krypton storage. Molecular sieve 5A achieved this separation in dissolver off-gas streams containing relatively low krypton and CO/sub 2/ concentrations and in krypton-rich product streams from processes such as the krypton absorption in liquid carbon dioxide (KALC) process. The CO/sub 2//krypton separation unit is a 30.5-cm-diameter x 1.8-m-long column containing molecular sieve 5A. The loading capacity for CO/sub 2/ was determined for gas mixtures containing 250 ppM to 2.2% CO/sub 2/ and 170 to 750 ppM krypton in either N/sub 2/ or air. Gas streams rich in CO/sub 2/ were diluted with N/sub 2/ to reduce the temperature rise from the heat of adsorption, which would otherwise affect loading capacity. The effluent CO/sub 2/ concentration prior to breakthrough was less than 10 ppM, and the adsorption capacity for krypton was negligible. Krypton was monitored on-line with a time-of-flight mass spectrometer and its concentration determined quantitatively by a method of continuous analysis, i.e., selected-ion monitoring. Radon-220 was treated by holdup and decay on a column of synthetic H-mordenite. The Rn-220 concentration was monitored on-line with flow-through diffused-junction alpha detectors. Single-channel analyzers were utilized to isolate the 6.287-MeV alpha energy band characteristic of Rn-220 decay from energy bands due to daughter products.

Research Organization:
General Atomic Co., San Diego, CA (USA)
DOE Contract Number:
AT03-76SF71053
OSTI ID:
5363147
Report Number(s):
GA-A-16809; CONF-820833-5; ON: DE82018288
Resource Relation:
Conference: 17. DOE nuclear air cleaning conference, Denver, CO, USA, 1 Aug 1982
Country of Publication:
United States
Language:
English

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