Philippe Martin, M. Ripert, G. Carlot
Mar 15, 2004
Citations
3
Influential Citations
33
Citations
Journal
Journal of Nuclear Materials
Abstract
Abstract Molybdenum is one of the most abundant fission products created in UO 2 fuel. Post-irradiation examinations show that molybdenum is mainly associated with rhodium, ruthenium, palladium and technetium in metallic precipitates. However, for low burn-ups, these five metal particles cannot be detected. In order to determine the chemical state of molybdenum in UO 2 , XANES experiments were carried out on fresh UO 2 pellets implanted with Mo ions. The measurements performed at the oxygen K and molybdenum L III edges showed a correlation between the chemical state of molybdenum and the O/U ratio of the UO 2 matrix. Indeed, the molybdenum located at the grain boundaries is present in both metallic and +IV oxidation states. To our knowledge, this study is the first experimental evidence of the solution annealing of Mo +IV in the cationic lattice of UO 2 . Thus, when molybdenum is oxidised at the +IV state, it remains in solution in the UO 2 matrix.