The selective removal of {sup 90}Sr and {sup 137}Cs from liquid low-level waste at Oak Ridge National Laboratory
Methods are being developed for the selective removal of the two principal radioactive contaminants, {sup 90}Sr and {sup 137}Cs, from liquid low-level waste generated and/or stored at Oak Ridge National Laboratory. These methods are to be used in a future centralized treatment facility at ORNL. Removal of {sup 90}Sr in the proposed treatment flashed is based on coprecipitation from strongly alkaline waste by adding stable strontium to the waste solution. Ferric sulfate, added with the stable strontium, improves the {sup 90}Sr removal and aids in the flocculation of the strontium carbonate (SrCO{sub 3}) precipitate. After separation of the solids, the resultant supernate is adjusted to pH 8 for the cesium removal treatment. Upon pH adjustment, aluminum originally present in the untreated alkaline waste precipitates and sorbs an additional amount of {sup 90}Sr. Cesium is removed from the neutralized waste by two sequential treatments with potassium cobalt hexacyanoferrate (KCCF) slurry formed by the addition of potassium ferrocyanide (K{sub 4}Fe(CN){sub 6}) and cobalt nitrate (Co(NO{sub 3}){sub 2}) solutions. The cumulative decontamination factors (DFs) for {sup 90}Sr and {sup 137}Cs in benchscale studies are 4900 and 1 x 10{sup 6}, respectively, if high speed centrifugation is used for the liquid/solid separations. Efforts are now underway to evaluate process-scale techniques to perform the liquid/solid separations required for removal of SrCO{sub 3} and {sup 137}Cs-bearing hexacyanoferrate solids from the treated waste solution.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 236252
- Report Number(s):
- CONF-9504255--1; ON: DE96010577
- Country of Publication:
- United States
- Language:
- English
Similar Records
Decontamination of alkaline radioactive waste by ion exchange
REMOVAL OF Cs{sup 137}, Sr{sup 90}, AND Ru{sup 106} FROM ORNL PLANT WASTES BY SORPTION ON VARIOUS MINERALS