XPS study of external α-radiolytic oxidation of UO2 in the presence of argon or hydrogen

• UO2 pellets exposed to 1.85 MBq and 3.30 MBq Am-241 sources with a 30 μm separation in solution were studied under Ar and H2 atmospheres. The 1.85 MBq Am-241 source was shown to have a too low radiolytic production to cause any measurable change in UO2 surface oxidation state. However, a significant oxidation was observed after exposure to the 3.30 MBq source under Ar atmosphere through the production of U(V), as seen from the U4f7/2-peak deconvolution and valence band peak analysis. The H2 atmosphere was shown to suppress the oxidation of the UO2 pellet surface as well as the dissolution in both Milli-Q and NaHCO3 solutions. The dissolved uranium concentration was reduced by a factor 10 under H2 atmosphere as compared to the Ar atmosphere experiments.

Ämnesord

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

UO2

hydrogen effect

dissolution

oxidation

x-ray photoelectron spectroscopy

radiolysis

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