|About this Abstract
||Materials Science & Technology 2019
||Materials Issues in Nuclear Waste Management
||Energetics and Structure of Uranium-incorporated Iron Oxides
||Andy Lam, Katherine Morris, Samuel Shaw, Jesús M Velázquez, Alexandra Navrotsky
|On-Site Speaker (Planned)
Iron oxides are ubiquitous in nature and may be found as corrosion products in geological waste repositories. Their ability to structurally incorporate uranium, rather than only surface adsorb, is a promising immobilization pathway for remediating contaminated waters. However, it is not yet clear how stability scales with incorporation capacity. Iron oxide polymorphs have been synthesized with high levels of uranium incorporation and phase purity, e.g. 5 wt % U in hematite. Such samples facilitate studying thermodynamic costs of uranium loading through oxide melt solution calorimetry. Determining their formation enthalpies relative to mixtures of iron and uranium oxides may constrain stability of uranium retention over geologic timescales. X-ray absorption spectroscopy has been performed to explore local U coordination for varying degrees of incorporation. These complementary techniques provide insight to the stability and effectiveness of iron oxides for radionuclide immobilization.