Prediction of glass durability as a function of environmental conditions
A thermodynamic model of glass durability is applied to natural, ancient, and nuclear waste glasses. The durabilities of over 150 different natural and man-made glasses, including actual ancient Roman and Islamic glasses (Jalame ca. 350 AD, Nishapur 10-11th century AD and Gorgon 9-11th century AD), are compared. Glass durability is a function of the thermodynamic hydration free energy, ..delta..G/sub hyd/, which can be calculated from glass composition and solution pH. The durability of the most durable nuclear waste glasses examined was /approximately/10/sup 6/ years. The least durable waste glass formulations were comparable in durability to the most durable simulated medieval window glasses of /approximately/10/sup 3/ years. In this manner, the durability of nuclear waste glasses has been interpolated to be /approximately/10/sup 6/ years and no less than 10/sup 3/ years. Hydration thermodynamics have been shown to be applicable to the dissolution of glass in various natural environments. Groundwater-glass interactions relative to geologic disposal of nuclear waste, hydration rind dating of obsidians, andor other archeological studies can be modeled, e.g., the relative durabilities of six simulated medieval window glasses have been correctly predicted for both laboratory (one month) and burial (5 years) experiments. Effects of solution pH on glass dissolution has been determined experimentally for the 150 different glasses and can be predicted theoretically by hydration thermodynamics. The effects of solution redox on dissolution of glass matrix elements such as SI and B have shown to be minimal. The combined effects of solution pH and Eh have been described and unified by construction of thermodynamically calculated Pourbaix (pH-Eh) diagrams for glass dissolution. The Pourbaix diagrams have been quantified to describe glass dissolution as a function of environmental conditions by use of the data derived from hydration thermodynamics. 56 refs., 7 figs.
- Research Organization:
- Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Plant
- DOE Contract Number:
- AC09-76SR00001
- OSTI ID:
- 5043824
- Report Number(s):
- DP-MS-87-158; CONF-8804134-1; CONF-8804134-; ON: DE88010529
- Resource Relation:
- Conference: Symposium on materials stability and environmental degradation, Reno, NV, USA, 5 Apr 1988
- Country of Publication:
- United States
- Language:
- English
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12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
GLASS
DISSOLUTION
STABILITY
RADIOACTIVE WASTE DISPOSAL
UNDERGROUND DISPOSAL
WASTE FORMS
ARCHAEOLOGICAL SPECIMENS
BOROSILICATE GLASS
GROUND WATER
HYDRATION
PH VALUE
REDOX POTENTIAL
THERMODYNAMICS
HYDROGEN COMPOUNDS
MANAGEMENT
OXYGEN COMPOUNDS
SOLVATION
WASTE DISPOSAL
WASTE MANAGEMENT
WATER
360604* - Materials- Corrosion
Erosion
& Degradation
052002 - Nuclear Fuels- Waste Disposal & Storage