Development of a SREX flowsheet for the separation of strontium from dissolved INEEL zirconium calcine
Laboratory experimentation has indicated that the SREX process is effective for partitioning {sup 90}Sr from acidic radioactive waste solutions located at the Idaho Nuclear Technology and Engineering Center. These laboratory results were used to develop a flowsheet for countercurrent testing of the SREX process with dissolved pilot plant calcine. Testing was performed using 24 stages of 2-cm diameter centrifugal contactors which are installed in the Remote Analytical Laboratory hot cell. Dissolved Run No.64 pilot plant calcine spiked with {sup 85}Sr was used as feed solution for the testing. The flowsheet tested consisted of an extraction section (0.15 M 4{prime},4{prime}(5{prime})-di-(tert-butylcyclohexo)-18-crown-6 and 1.5 M TBP in Isopar-L.), a 1.0 M NaNO{sub 3} scrub section to remove extracted K from the SREX solvent, a 0.01 M HNO{sub 3} strip section for the removal of Sr from the SREX solvent, a 0.25 M Na2CO{sub 3} wash section to remove degradation products from the solvent, and a 0.1 M HNO{sub 3} rinse section. The behavior of {sup 85}Sr, Na, K, Al, B, Ca, Cr, Fe, Ni, and Zr was evaluated. The described flowsheet successfully extracted {sup 85}Sr from the dissolved pilot plant calcine with a removal efficiency of 99.6%. Distribution coefficients for {sup 85}Sr ranged from 3.6 to 4.5 in the extraction section. With these distribution coefficients a removal efficiency of approximately >99.99% was expected. It was determined that the lower than expected removal efficiency can be attributed to a stage efficiency of only 60% in the extraction section. Extracted K was effectively scrubbed from the SREX solvent with the 1.0 M NaNO{sub 3} resulting in only 6.4% of the K in the HLW strip product. Sodium was not extracted from the dissolved calcine by the SREX solvent; however, the use of a 1.0 M NaNO{sub 3} scrub solution resulted in a Na concentration of 70 mg/L (12.3% of the feed concentration) in the HLW strip product. Al, B, Ca, Cr, Fe, Ni, and Zr were determined to be essentially inextractable.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- AC07-94ID13223
- OSTI ID:
- 752573
- Report Number(s):
- INEEL/EXT-99-00001; TRN: US0001342
- Resource Relation:
- Other Information: PBD: 1 Jan 1999
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RADIOACTIVE WASTE PROCESSING
STRONTIUM 90
RADIOACTIVE WASTE FACILITIES
FLOWSHEETS
PERFORMANCE TESTING
SOLVENT EXTRACTION
CROWN ETHERS
CENTRIFUGATION
STRONTIUM-90
SREX PROCESS
RADIOACTIVE WASTE
FLOWSHEET
COUNTERCURRENT TESTING
CENTRIFUGAL CONTACTORS
EXTREACTION SECTION
SCRUB SECTION
WASH SECTION
RINSE SECTION
REMOVAL EFFICIENCY
SODIUM