Effect of inorganic aqueous species on the long term behavior of nuclear glass
- Commissariat a l`Energie Atomique, Bagnols-sur-Ceze (France). Rhone Valley Research Center
The influence of inorganic aqueous species on the dissolution mechanisms and kinetics of the French LWR reference glass is investigated experimentally by static mode tests at imposed pH values (2.5 and 9) in highly dilute media, i.e. with glass-surface-area-to-solution-volume ratios on the order of 0.1 cm{sup {minus}1}. Three types of species capable of interacting with the glass surface have been identified: species generally released into solution by glass corrosion, species present in natural groundwater, and solid species liable to be found in a repository nearfield environment. The effects of glass component species are negligible except for dissolved silica, which retards glass dissolution; test results obtained with silica in solution partly call into question the generally accepted kinetic model for glass dissolution in basic media, in which the overall kinetics are assumed to be controlled exclusively by H{sub 4}SiO{sub 4}. No effect was observed for groundwater species other than the pyrophosphates, which catalyze the glass dissolution reaction in basic media; dihydrogen phosphate ions also inhibit glass dissolution in highly acidic media through chemisorption on the glass. Finally, in media constituted by insoluble metallic and rare earth ions, retention of a significant silica fraction was generally observed in the alteration film on the glass surface; inhibition of glass corrosion was observed only in the presence of aluminum hydroxide. The principal conclusion that may be drawn from these tests concerns the key role of the pH in interactions between the aqueous species and the glass matrix. The pH governs the adsorption rate of aqueous species on the glass surface, which in turn modifies the glass dissolution kinetics.
- OSTI ID:
- 183000
- Report Number(s):
- CONF-950917-; ISBN 0-7918-1219-7; TRN: IM9608%%369
- Resource Relation:
- Conference: 5. international conference on radioactive waste management and environmental remediation, Berlin (Germany), 3-9 Sep 1995; Other Information: PBD: 1995; Related Information: Is Part Of Fifth international conference on radioactive waste management and environmental remediation -- ICEM `95: Proceedings. Volume 1: Cross-cutting issues and management of high-level waste and spent fuel; Slate, S.; Feizollahi, F.; Creer, J. [eds.]; PB: 900 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
GLASS
CORROSION
WASTE FORMS
RADIOACTIVE WASTE FACILITIES
WATER INFLUX
VITRIFICATION
RADIOACTIVE WASTES
PH VALUE
BORON HYDROXIDES
SODIUM COMPOUNDS
CALCIUM COMPOUNDS
POTASSIUM COMPOUNDS
CHLORIDES
PHOSPHATES
NITRATES
SULFATES
CATALYTIC EFFECTS
ALUMINIUM
IRON
ZINC
ZIRCONIUM
CHROMIUM
NICKEL
NEODYMIUM
ALUMINIUM HYDROXIDES
CORROSIVE EFFECTS
CHEMICAL COMPOSITION
EXPERIMENTAL DATA