Approximately 250,000 metric tons of nuclear waste currently sit in short term storage around the world with the US accounting for over 90,000. Deep geologic repositories (DGRs) are widely considered the best solution to dispose/storge this waste. The general design of DGRs is widely agreed upon, but some specific aspects optimum design is still uncertain and understudied. One of these aspects is the cement that is used as containment and backfill in some DGR designs, including the design that was implemented in the US at Yucca Mountain until recently. My research focuses on studying different cement formulations to understand how the cement will contribute to the safety of a DGR and how this will change over the lifetime of the DGR. Using primarily laboratory X-ray spectrometers, including one built specifically for this study, as well as tomography, XRD, Kelvin probe, ICP-OES, and other analytic measurements I study element specific chemistry of the cements. Through this work I hope to gain an understanding of how the cement interacts with radionuclides and how the cement will structurally and chemically change on both a micro and macro scale over the 100,000+ year lifetime of a DGR.
Advisor: Gerald Seidler – Physics