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

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 characterization via diffuse 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)2ยท2H2O 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.

author list (cited authors)

  • Yu, X., Einkauf, J. D., Bryantsev, V. S., Cheshire, M. C., Reinhart, B. J., Autschbach, J., & Burns, J. D.

publication date

  • January 1, 2021 11:11 AM