The Incorporation of Cerium in Zirconolite
Keyword(s):
X Ray
◽
ABSTRACTZirconolite (CaZrTi2O7) is the primary actinide-bearing Synroc phase for the immobilisation of high-level nuclear waste. Using X-ray absorption spectroscopy and microanalysis we have investigated the incorporation of cerium, as a simulant for plutonium, on both zirconolite's Ca and Zr sites under a range of redox conditions. The Ce valence state was found to vary between Ce3+ and Ce4+ depending on the both the sintering atmosphere and temperature. The existence of alternative charge compensation schemes, predominantly cation vacancies, in addition to those used in the sample design was inferred in many of the zirconolites and will be discussed in detail.