Spectroscopic characterization of neptunium(vi), plutonium(vi), americium(vi) and neptunium(v) encapsulated in uranyl nitrate hexahydrate

Academic Article

Abstract

  • The coordination of crystalline products resulting from the co-crystallization of Np(vi), Pu(vi), Am(vi), and Np(v) with uranyl nitrate hexahydrate (UNH) has been revealed through solid-state spectroscopic characterizationviadiffuse reflectance UV-Vis-NIR spectroscopy, SEM-EDS, and extended X-ray absorption fine structure (EXAFS) spectroscopy. Density functional and multireference wavefunction calculations were performed to analyze the An(vi/v)O2(NO3)2·2H2O electronic structures and to help assign the observed transitions in the absorption spectra. EXAFS show a similar coordination between the U(VI) in UNH and Np(vi) and Pu(vi); while Am resulted in a similar coordination to Am(iii), as reduction of Am(vi) occurred prior to EXAFS data being obtained. The co-crystallization of the oxidized transuranic species—penta- and hexavalent—with UNH, represents a significant advance from not only a practical standpoint in providing an elegant solution for used nuclear fuel recycle, but also as an avenue to expand the fundamental understanding of the 5f electronic behavior in the solid-state.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Yu X; Einkauf JD; Bryantsev VS; Cheshire MC; Reinhart BJ; Autschbach J; Burns JD
  • Start Page

  • 13228
  • End Page

  • 13241
  • Volume

  • 23
  • Issue

  • 23