1. Scope

1.1 Test method in which the dissolution rate of a homogenous silicate glass, including nuclear waste glasses, is measured through corrosion of monolithic samples in stirred dilute conditions.
1.2 Various test solutions can be used at temperatures less than 100 °C. While the durability of the glass can be impacted by dissolving species from the glass, and thus the test can be conducted in dilute conditions or concentrated condition to determine the impact of such species, care must be taken to avoid or account for the production of alteration layers which may confound the step height measurements.
1.3 Tests are carried out via the placement of the monolithic samples in a large well-mixed volume of solution, achieving a high volume to surface area ratio resulting in dilute conditions with agitation of the solution.
1.4 This practice excludes test methods using a powdered glass samples, or in which the reactor solution saturates with time.
1.5 Tests may be conducted with demineralized water, chemical solutions (buffered solutions, simulated groundwater) or actual groundwater.
1.6 Tests are conducted with monolithic glass samples with at least a single flat face. Although having two plane-parallel faces is helpful for certain step height measurements, it is not required. The geometric dimensions of the monolith are not required to be known. The reacted monolithic sample is to be analyzed following the reaction to measure a corroded depth to determine dissolution rate.
1.7 Tests may be performed with radioactive samples. However, safety concerns working with radionuclides are not addressed in this test method.
1.8 Data from these tests can be used to determine the value of kinetic rate model parameters needed to predict glass corrosion behavior over long periods of time. For an example, see Practice C1174.
1.9 This test method must be performed in accordance with all quality assurance requirements for acceptance of the data.
1.10 The values stated in SI unites are regarded as the standard. Any values given in parentheses are for information only.

Keywords

Glass dissolution rate, Glass corrosion, Nuclear waste glass.

Rationale

Generate an ASTM standard test method in which the dissolution rate of a homogenous silicate glass, including nuclear waste glasses, is measured through corrosion of monolithic samples in dilute conditions. Various test solutions can be used at temperatures less than 100 °C. Tests may be conducted with demineralized water, chemical solutions (buffered solutions, simulated groundwater), or actual disposal site groundwater. Tests will be carried out via placement of monolithic samples with at least a single flat face in an actively-stirred large volume of solution, achieving a high volume to surface area ratio resulting in dilute conditions. The reacted monolithic sample is to be analyzed following the reaction time to measure a corroded depth to determine dissolution rate. Data from these tests can be used to determine the value of kinetic rate law parameters needed to predict glass corrosion behavior over long periods of time.

The title and scope are in draft form and are under development within this ASTM Committee.