The anodic dissolution Of (UO2)-O-IV has been studied at 60 degrees C in 0. 1 mol dm (-3) KCI using a range of electrochemical methods and X-ray photoelectron spectroscopy (XPS). The results were compared to previous results obtained at 22 degrees C. This comparison shows that the threshold for the onset of anodic dissolution (-400 mV versus SCE) is not noticeably changed by this increase in temperature. However, both the oxidation of the surface (to (UO2+x)-O-IV/V) and the rate of anodic dissolution (as (UO22+)-O-VI) leading to the formation of a (UO3)-O-VI-yH(2)O deposit are accelerated at the higher temperature. The XPS analysis shows that the conversion of U-v-U-VI occurs at lower potentials at 60 degrees C. Consequently, once the surface becomes blocked by the presence of a (UO3)-O-VI yH(2)O deposit, rapid dissolution coupled to uranyl ion hydrolysis causes the development of locally acidified sites within the fuel surface at lower potentials at the higher temperature. (c) 2007 Elsevier Ltd. All rights reserved.