Vanadium pentoxide, V2O5, has been proposed as an oxidant for the stabiliza
tion of reduced forms of plutonium within pyrochemical salt residues from p
lutonium pyrochemical processes at the Rocky Flats Environmental Technology
Site because of its large reduction potential and its ability to react via
normal solid-state reactions. However, when V2O5 was used to oxidize actua
l process residues results were highly variable. This paper discusses the r
eaction chemistry of PuCl3, Pu degrees and PuOCl with V2O5 under a variety
of conditions, including in the presence and absence of a NaCl/KCl salt mat
rix. This work is the first systematic study of the solid-state oxidation o
f plutonium species by vanadium pentoxide. For PuCl3 a greater than or equa
l to 1:1 V2O5:PuCl3 ratio is needed for complete oxidation. Increasing the
amount of V2O5 from 1 to 2 equivalents increases the contribution of side r
eactions, including reactions of V2O5 with the process equipment and/or sal
t matrix, and produces undesirable non-volatile ternary and quaternary vana
dium compounds. The oxidation of PuOCl is similar to that of PuCl3. Greater
than a 1:1 V2O5:PuOCl ratio is required to achieve adequate conversion of
PuOCI to PuO2. Oxidation of Pu degrees by V2O5 is more complex than the PuC
l3, or PuOCl oxidations. Complete oxidation of Pu degrees to Pu(IV) in the
presence of the salt matrix does not occur with up to 6 equivalents of V2O5
. However, conversion of Pu degrees to Pu(IV) occurs rapidly in the absence
of the salt matrix. (C) 2001 Elsevier Science B.V. All rights reserved.