Physico-chemical properties of international simple glass (ISG) nuclear waste simulants: Luminescence baseline study

José A. Jiménez, Charles L. Crawford, Robert J. Lascola

Research output: Contribution to journalArticlepeer-review

Abstract

Borosilicate glass has been adopted internationally for the treatment of nuclear waste with the object of long-term stabilization through vitrification. Aiming to facilitate experimental comparisons across laboratories, the six-component international simple glass (ISG) was developed as benchmark. The original ISG produced by Mo-SCI Corporation (Rolla, MO) was distributed and characterized for different physical properties thus serving as reference for further studies. Still, photoluminescence (PL) properties, which may be useful for scrutinizing radiation-induced damage, have not been reported. Further, the original ISG contained significant iron impurities, which may present interference in various studies (e.g., optical). Consequently, two new ISG analogs lacking iron impurities (labeled ISG-1 [closest composition to original ISG] and ISG-2 [some MgO added at expense of CaO]) were synthesized by Corning Inc. (Corning, NY) (also doped with lanthanum for subsequent corrosion tests involving atom probe tomography), which remain to be fully characterized. Accordingly, this work was undertaken to perform a comprehensive study comparing the three ISG specimens. Various characterizations were then performed on the pristine glasses: X-ray diffraction and vibrational spectroscopy (structural properties); static-leach product consistency test (PCT, dissolution behavior); dilatometry and calorimetry measurements (thermal properties); and optical absorption with Tauc and Urbach plots analysis, followed by PL spectroscopy with decay kinetics assessment (optical properties). While the general structural features appeared similar among the glasses, the deconvolution of Raman spectra suggested a lower degree of connectivity in the silica network for ISG-2. In addition, some differences were indicated from the PCT results and thermal properties assessed, which were discussed based on compositional variations. Further on, the optical properties were shown to be the most distinct. The optical absorption of the original ISG was characterized by Fe2+/Fe3+ impurities not detected for ISG-1 and ISG-2. The glasses all exhibited two main PL features (∼1.8 and 2.5 eV) with multiexponential decay behavior apparently of intrinsic origin. In addition, ISG-1 and ISG-2 showed a third high-energy (∼3.4 eV) fast-decaying contribution tentatively credited to tin impurities, which appeared most significantly for ISG-1. The results are expected to serve as baseline for future studies simulating the effects of radioactive element decay.

Original languageEnglish (US)
Pages (from-to)4009-4026
Number of pages18
JournalJournal of the American Ceramic Society
Volume105
Issue number6
DOIs
StatePublished - Jun 2022

Keywords

  • borosilicate glass
  • dissolution tests
  • nuclear waste vitrification
  • optical properties
  • structural properties
  • thermal properties

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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