Browsing by Author "Day, Delbert E."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Glass formation and chemical durability of dysprosium lithium borate glasses intended for in vivo radiation synovectomy
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2001) Conzone, Samuel D.; Hemrick, James G.; Day, Delbert E.
    The glass formation and structure/property relationships for Dy2O3-Li2O-B2O3 glasses were investigated. Such glasses are currently being considered for in vivo radiation delivery vehicles. Chemical dissolution tests were conducted in simulated synovial fluid (pH 7.4, at 37 °C, for 11 d) to evaluate the release of dysprosium from selected glasses. The chemical durability, Tg, nD and density increased as either the Li2O or Dy2O3 content in a glass was increased. Such property trends are attributed to increased cross-linking within the glass structure as BO3 triangles are converted to BO4 tetrahedra. Αproposed structural model assumes dysprosium is incorporated into the glass with a coordination number of eight and is surrounded by four BO4 tetrahedra. Glasses containing ≥ 1.0 mol% Dy2O3 released less than 0.1 % of their initial dysprosium content after being immersed in simulated synovial fluid for 11 d at 37 °C. These glasses are considered safe for in vivo radiation delivery from the standpoint of radiation release, since dysprosium will be the only radioisotope in the glass during treatment.
  • Thumbnail Image
    Item
    Properties and solubility of chrome in iron alumina phosphate glasses containing high level nuclear waste
    (Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2004) Huang, Wenhai; Day, Delbert E.; Ray, Chandra S.; Kim, Cheol-Woon; Reis, Signo T. D.
    Chemical durability, glass formation tendency, and other properties of iron alumina phosphate glasses containing 70 wt% of a simulated high level nuclear waste (HLW), doped with different amounts of Cr2O3, have been investigated. All of the iron alumina phosphate glasses had an outstanding chemical durability as measured by their small dissolution rate (1 ∙ 10^-9 g/(cm2 ∙ min)) in deionized water at 90 °C for 128 d, their low normalized mass release as determined by the Product Consistency Test (PCT) and a barely measurable corrosion rate of < 0.1 g/(m2 ∙ d) after 7 d at 200 °C by the Vapor Hydration Test (VHT). The solubility limit for Cr2O3 in the iron phosphate melts was estimated at 4.1 wt%, but all of the as-annealed melts contained a few percent of crystalline Cr2O3 that had no apparent effect on the chemical durability. The chemical durability was unchanged after deliberate crystallization, 48 h at 650 °C. These iron phosphate waste forms, with a waste loading of at least 70 wt%, can be readily melted in commercial refractory crucibles at 1250°C for 2 to 4 h, are resistant to crystallization, meet all current US Department of Energy requirements for chemical durability, and have a solubility limit for Cr2O3 which is at least three times larger than that for borosilicate glasses.