1 research outputs found
Actinide Dioxides in Water: Interactions at the Interface
A comprehensive understanding of chemical interactions
between water and actinide dioxide surfaces is critical for safe operation
and storage of nuclear fuels. Despite substantial previous research,
understanding the nature of these interactions remains incomplete.
In this work, we combine accurate calorimetric measurements with first-principles
computational studies to characterize surface energies and adsorption
enthalpies of water on two fluorite-structured compounds, ThO<sub>2</sub> and CeO<sub>2</sub>, that are relevant for understanding
the behavior of water on actinide oxide surfaces more generally. We
determine coverage-dependent adsorption enthalpies and demonstrate
a mixed molecular and dissociative structure for the first hydration
layer. The results show a correlation between the magnitude of the
anhydrous surface energy and the water adsorption enthalpy. Further,
they suggest a structural model featuring one adsorbed water molecule
per one surface cation on the most stable facet that is expected to
be a common structural signature of water adsorbed on actinide dioxide
compounds