Nitrate effects on uranium and plutonium extractions

NUCL 12

Amber D. Wright, ambdawn@hotmail.com and Ken Czerwinski, czerwin2@unlv.nevada.edu. Department of Chemistry and Harry Reid Center, University of Nevada, Las Vegas, 4505 Maryland Parkway, Box 454003, Las Vegas, NV 89154-4003
Uranium and plutonium solvent extraction by tributylphosphate has been extensively investigated as part of nuclear fuel reprocessing. Extraction is based organic phase neutral complexes (i.e., Pu(NO3)4•2TBP). However, data needed for detailed process separations modeling of Pu are not entirely available, particularly the role nitrate plays in speciation. To address this issue, an initial study on the extraction of uranium as a function of nitrate concentration is performed. The experiments will examine the aqueous and organic phase concentrations of nitrate, acid, and uranium by spectroscopy, chromatography, and titration. The results provide thermodynamic data describing the extracted species. The role of the di- and trinitrato uranyl species in the aqueous and organic phase will be examined and compared to existing literature values for the relevant species. The experimental results can be incorporated into extraction codes and will be used as the basis of future plutonium experiments.