Solubility interpretations of leach tests on nuclear waste glass

Journal Article · Sat Dec 31 23:00:00 EST 1983 · Nucl. Chem. Waste Manage.; (United States)

DOI:https://doi.org/10.1016/0191-815X(84)90010-X· OSTI ID:5876876

Strachan, D M; Krupka, K M

A one-year leach test at 90/sup 0/C was conducted on specimens of PNL 76-68 borosilicate glass, a simulated nuclear waste glass. The experimental method was MCC-1, one of the standard leach tests developed by the Materials Characterization Center (MCC). The leachant solutions included deionized water, a silicic acid/sodium bicarbonate solution, and a concentrated K-Mg-Na-Cl brine. Phase characterization techniques and geochemical codes were used to identify possible solubility and sorption controls for the constituents dissolved in the final leach solutions. In the non-brine solutions, an alteration layer of 30-50 ..mu..m is formed that consists mainly of an amorphous Fe(OH)/sub 3/. In addition, a zinc silicate phase precipitated on the glass surface and appears to control the concentrations of dissolved Cs and Si. Calculations with the MINTEQ geochemical code identified possible equilbrium solubility controls for dissolved Fe, Ca, Si, Zn, Pb, P, and F. These calculations also permitted an estimation of the pH at the temperature of the leach experiments. The PHREEQE geochemical code was used to predict the steady state concentrations of Ca/sup 2 +/ and Sr/sup 2 +/ in the final leachates by assuming their sorption on solid amorphous Fe(OH)/sub 3/. For the leach tests completed in the brine solution, a magnesium silicate phase precipitated on the glass surface and may have been responsible for the observed decrease in the concentration of the dissolved Si. This solid phase was tentatively identified as sepiolite and/or possibly talc. These results were compared to mineral solubilities calculated from the MINTEQ geochemical code.

• Research Organization: Pacific Northwest Laboratories, Richland, Washington
• OSTI ID: 5876876
• Journal Information: Nucl. Chem. Waste Manage.; (United States), Journal Name: Nucl. Chem. Waste Manage.; (United States) Vol. 5:1; ISSN NCWMD
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
360604 -- Materials-- Corrosion
Erosion
& Degradation
ACID CARBONATES
ALKALI METALS
ALKALINE EARTH METALS
BOROSILICATE GLASS
BRINES
CALCIUM
CESIUM
CHEMISTRY
COMPUTER CODES
DATA PROCESSING
DISPERSIONS
DISSOLUTION
ELEMENTS
FLUORINE
GEOCHEMISTRY
GLASS
HALOGENS
IRON
LEACHING
LEAD
MANAGEMENT
METALS
MIXTURES
NONMETALS
PHOSPHORUS
PROCESSING
RADIOACTIVE WASTE DISPOSAL
SEMIMETALS
SEPARATION PROCESSES
SILICON
SIMULATION
SOLUBILITY
SOLUTIONS
STRONTIUM
TESTING
TRANSITION ELEMENTS
WASTE DISPOSAL
WASTE MANAGEMENT
ZINC