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Demonstration of the UNEX Process for the Simultaneous Separation of Cesium, Strontium, and the Actinides from Actual INEEL Tank Waste

Technical Report ·
DOI:https://doi.org/10.2172/774229· OSTI ID:774229
 [1]; ;  [2]; ; ; ; ;  [3];  [4]
  1. Idaho National Engineering and Environmental Laboratory
  2. INEEL
  3. V. G. Khlopin Radium Institute
  4. MAYAK Production Association
A universal solvent extraction (UNEX) process for the simultaneous separation of cesium, strontium, and the actinides from actual radioactive acidic tank waste was demonstrated at the Idaho National Engineering and Environmental Laboratory. The waste solution used in the countercurrent flowsheet demonstration was obtained from tank WM-185. The UNEX process uses a tertiary solvent containing 0.08 M chlorinated cobalt dicarbollide, 0.5% polyethylene glycol-400 (PEG-400), and 0.02 M diphenyl-N,N-dibutylcarbamoyl phosphine oxide (Ph2Bu2CMPO) in a diluent consisting of phenyltrifluoromethyl sulfone (FS-13). The countercurrent flowsheet demonstration was performed in a shielded cell facility using 24 stages of 2-cm diameter centrifugal contactors. Removal efficiencies of 99.4%, 99.995%, and 99.96% were obtained for 137Cs, 90Sr, and total alpha, respectively. This is sufficient to reduce the activities of 137Cs, 90Sr, and actinides in the WM-185 waste to below NRC Class A LLW requirement s. Flooding and/or precipitate formation were not observed during testing. Significant amounts of the Zr (87%), Ba (>99%), Pb (98.8%), Fe (8%), Ca (10%), Mo (32%), and K (28%) were also removed from the feed with the universal solvent extraction flowsheet. 99Tc, Al, Hg, and Na were essentially inextractable (<1% extracted).
Research Organization:
Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID (US)
Sponsoring Organization:
USDOE Office of Environmental Management (EM) (US)
DOE Contract Number:
AC07-99ID13727
OSTI ID:
774229
Report Number(s):
INEEL/EXT-99-00954
Country of Publication:
United States
Language:
English