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WK82 New Test Method for Measurement of the Glass Dissolution Rate Using the Single-Pass Flow-Through Test Method

Developed by Subcommittee: C26.13
See Related Work by this Subcommittee
Date Initiated: 02-07-2003

1. Scope

1.1 This practice describes a single-pass flow-through (SPFT) test method that can be used to measure the dissolution rate of a homogeneous silicate glass, including nuclear waste glasses, in various test solutions at temperatures less than 100¬C. Tests may be conducted under conditions in which the effects from dissolved species on the dissolution rate are minimized to measure the forward dissolution rate at specific values of temperature and pH, or to measure the dependence of the dissolution rate on the concentrations of various solute species.
1.2 Tests are conducted by pumping solutions in either a continuous or pulsed flow mode through a reaction cell that contains the test specimen. Tests must be conducted at several solution flow rates to evaluate the effect of the flow rate on the glass dissolution rate.
1.3 This practice excludes static test methods in which flow is simulated by manually removing solution from the reaction cell and replacing it with fresh solution.
1.4 Tests may be conducted with demineralized water, chemical solutions (such as pH buffer solutions, simulated groundwater solutions, and brines), or actual groundwater.
1.5 Tests may be conducted with crushed glass of a known size fraction or monolithic specimens having known geometric surface area. The reacted solids may be examined to provide additional information regarding the behavior of the material in the test and the reaction mechanism.
1.6 Tests may be conducted with glasses containing radionuclides. However, this test method does not address safety issues for radioactive samples.
1.7 Data from these tests can be used to determine the values of kinetic model parameters needed to calculate the glass corrosion behavior in a disposal system over long times (for example, see Standard C 1174).
1.8 This test method must be performed in accordance with all quality assurance requirements for acceptance of the data.
1.9 This standard does not purport to address the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. The single-pass flow-through (SPFT) test method is used to measure the dissolution rate of a homogeneous silicate glass, including nuclear waste glasses, in various test solutions at temperatures less than 100—C. Tests may be conducted under conditions in which the effects from dissolved species on the dissolution rate are minimized to measure the forward dissolution rate at specific values of temperature and pH, or to measure the dependence of the dissolution rate on the concentrations of various solute species..

The SPFT draft standard was last balloted in 2002, received a few negative votes focused on the Precision and Bias section, a number of which were found to be substantive. The SPFT Task Group within Subcommittee C26.13, Spent Fuel and High Level Waste, has completed a round robin which has allowed the Precision and Bias section to be completely rewritten. No changes were made to any other sections.

Keywords
single-pass flow-through, glass dissolution rate

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