Actinide distribution in a stainless steel15 wt% zirconium high-level nuclear waste form Academic Article uri icon

abstract

  • Actinide-bearing waste forms are being produced from metallic remnants resulting from the electrometallurgical extraction of uranium from EBR-II spent fuel. The baseline metal waste form (MWF) is a stainless steel-15 wt% zirconium (SS-15Zr) alloy that may contain up to 10 wt% actinides, mostly in the form of uranium. This article presents the results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and neutron diffraction on SS-15Zr alloys containing uranium, plutonium, and neptunium. Neutron diffraction results showed that the addition of uranium to SS-15Zr does not result in the formation of discrete uranium-rich phases. The lattice parameters of the ZrFe2-type intermetallics are larger in uranium-containing SS-15Zr alloys and are consistent with the substitution of uranium at zirconium sites of the ZrFe2 lattice. SEM studies showed that actinides are present only in the ZrFe2-type intermetallics; moreover, both actinide-rich and actinide-deficient areas are found within the Laves compound. TEM showed that the simultaneous presence of multiple Laves polytypes, each with a different preference for the uranium atom, results in the uranium concentration gradients observed within the Laves intermetallics.

published proceedings

  • Journal of Nuclear Materials

author list (cited authors)

  • Keiser, D. D., Abraham, D. P., Sinkler, W., Richardson, J. W., & McDeavitt, S. M.

citation count

  • 31

complete list of authors

  • Keiser, DD||Abraham, DP||Sinkler, W||Richardson, JW||McDeavitt, SM

publication date

  • June 2000