Surface behaviour of uranium dioxide after immersion in mineral water studied by X-ray photoelectron spectroscopy

Abstract

X-Ray photoelectron spectroscopic (XPS) analysis has been carried out on samples of crystalline uranium dioxide following exposure to deionised or mineral water at 60 and 90°C for several weeks. A surface layer formed on UO₂ samples immersed in mineral water at 90°C has been identified as magnesium silicate precipitated from the mineral water. Depth-profiling experiments showed that this magnesium silicate deposit was ca. 100–200 nm in thickness and revealed the formation of a thin film of UO₃ between the bulk UO₂ and the outer magnesium silicate deposit.