Reaction of hydrogen peroxide with uranium zirconium oxide solid solution; Zirconium hinders oxidative uranium dissolution
Kumagai, Yuta
; Takano, Masahide
; Watanabe, Masayuki

We studied oxidative dissolution of uranium and zirconium oxide [(U,Zr)O
] in aqueous H
O
solution. The interfacial reaction is essential for anticipating how a (U,Zr)O
-based molten fuel may chemically degrade after a severe accident under influence of ionizing radiation. We conducted our experiments with (U,Zr)O
powder and quantitated the H
O
reaction via dissolved U and H
O
concentrations. The dissolution yield relative to H
O
consumption was far less for (U,Zr)O
compared to that of UO
. The reaction kinetics indicates that most of the H
O
catalytically decomposed to O
at the surface of (U,Zr)O
. We confirmed the H
O
catalytic decomposition via O
production (quantitative stoichiometric agreement). In addition, post-reaction Raman scattering spectra of the undissolved (U,Zr)O
showed no additional peaks (indicating a lack of secondary phase formation). The (U,Zr)O
matrix is much more stable than UO
against H
O
-induced oxidative dissolution.