The use of nuclear waste repositories necessitates good stewardship and waste management to minimize the effect on the environment. To accurately predict actinide affinity and mobility in nuclear waste repositories, it is important to understand actinide sorption behavior with clay materials and iron oxide minerals under repository conditions. The interactions of aqueous neptunium (Np) with clay and mineral surfaces have been studied previously, but the majority of data has been collected at ambient conditions. In this study, the sorption behavior of Np(V) with clay and mineral surfaces is investigated as a function of temperature and ionic strength, as elevated temperatures and high ionic strengths are the conditions expected in nuclear waste repositories. To complement the information garnered from the batch sorption experiments, X-ray absorption spectroscopy (XAS) will be used to further characterize the sorption samples and gain a molecular-level understanding of actinide sorption. Extended X-ray absorption fine structure (EXAFS) will reveal the local coordination environment and determine whether the sorbed Np is bound to the surface in an inner- or outer-sphere coordination.

Interactions of Np with clay and mineral surfaces at high temperatures and high ionic strengths

251st National Meeting (2016)

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