title: Characterization of Actinides Complexed to Nuclear Fuel Constituents Using ESI-MS.
abstract: Electrospray ionization-mass spectrometry (ESI-MS) was tested for its use in monitoring spent nuclear fuel (SNF) constituents including U, Pu, dibutyl phosphate (DBP), and tributyl phosphate (TBP). Both positive and negative ion modes were used to evaluate the speciation of U and Pu with TBP and DBP. Furthermore, apparent stability constants were determined for U complexed to TBP and DBP. In positive ion mode, TBP produced a strong signal with and without complexation to U or Pu, but, in negative ion mode, no TBP, U-TBP, or Pu-TBP complexes were observed. Apparent stability constants were determined for [UO2(NO3)2(TBP)2], [UO2(NO3)2(H2O)(TBP)2], and [UO2(NO3)2(TBP)3]. In contrast DBP, U-DBP, and Pu-DBP complexes were observed in both positive and negative ion modes. Apparent stability constants were determined for the species [UO2(DBP)], [UO2(DBP)3], and [UO2(DBP)4]. Analyzing mixtures of U or Pu with TBP and DBP yielded the formation of ternary complexes whose stoichiometry was directly related to the ratio of TBP to DBP. The ESI-MS protocols used in this study will further demonstrate the utility of ESI-MS and its applicability to process control monitoring in SNF reprocessing facilities.
authors.affiliation: Department of Civil and Environmental Engineering, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Luther W
authors.initials: LW
authors.lastname: McDonald
authors.affiliation: Chemical and Biological Signature Sciences Group, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Campbell
authors.affiliation: CEA, DEN, DANS, Department of Physico-Chemistry, F-91191 Gif-sur-Yvette, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Vercouter
authors.affiliation: Department of Chemistry, Washington State University , Pullman, Washington 99164, United States.
authors.forename: Sue B
authors.initials: SB
authors.lastname: Clark