The goal of this project is to determine the long term durability of Broborg Hillfort glass to support disposal of low-activity waste (LAW) glass in the Hanford Integrated Disposal Facility (IDF). This includes determining the ancient glass melting technology used so that synthetic glass of the sample composition can be generated and used in short-term accelerate aging test methods. Investigating natural and archeological glass alteration is essential to understand and predict long-term performance of nuclear waste glasses. While laboratory glass alteration experiments deliver short-term glass corrosion rates, natural and archeological analogues provide insight into long-term mechanism(s) driving glass corrosion in natural environments. These mechanisms are of interest to the nuclear waste glass community, as key radionuclides (e.g., technetium, half-life = 213,000 years) must be retained for thousands of years. For this purpose, ancient glasses found in a Swedish hillfort, containing elements used in simulated Hanford nuclear waste glass formulations, have been identified. These artifacts have been altered in a natural environment since ca. 400-575 AD. Non-destructive x-ray computed tomography (XCT) was used to select areas for sectioning, with subsequent micro x-ray diffraction (μ-XRD) to find amorphous glassy areas, micro x-ray fluorescence (μ-XRF) to determine glass chemistry and electron microscopy to analyze alteration layers on the glass surface. Characterization of these alteration layers proves a unique insight into natural process that drive glass corrosion over thousands of years. Data on two silicate glasses, one high iron and one low iron, found at the Broborg Hillfort will be presented, and the role of biodeterioration in their corrosion will be discussed.
C. Pearce, Jamie L. Weaver, E. Vicenzi
European Journal of Clinical Nutrition