Energetics of Ce and Pu incorporation into zirconolite waste-forms
Abstract
The General Utility Lattice Program (GULP) has been used to model the zirconolite lattice, calculate the energies of substituting Ce3+, Ce4+, Pu3+, Pu4+ and Fe3+ into the lattice both as single and multi-defect systems and model the formation of Ce3+, Ce4+, Pu3+ and Pu4+ doped zirconolite lattices. These results have been compared against experimental observations, with particular emphasis on those Ce containing solid solutions that exhibit Ce3+/Ce4+ mixed valence characteristics. It is found that the Ce3+/Ce4+ mixed valence is as a result of