Defense Waste Glass Studies Program: FY 1986 annual report: Salt repository project

DWGS is developing the necessary data and models to predict the radionuclide release behavior of defense waste glasses in a salt repository environment. In FY 1986, contributions toward achieving this goal were made under the following four subtasks: static testing; flow testing; colloid studies; and modeling. Static leach tests were performed with Savannah River Laboratory defense waste glass (SRL-165) in a high-magnesium salt brine (PBB3) at a temperature of 90/degree/C. The flow testing subtask was formed in FY 1986. A leach test procedure was developed, 'Flow-Through Waste Glass Testing,' which may be used in future work to study glass leaching mechanisms. Objective of the colloid studies subtask is to develop a submodel describing radionuclide release associated with colloids, provided such a submodel is needed. Under the modeling subtask, a simple glass dissolution model was formulated that balances the consumption and production of silicic acid to control the rate of glass dissolution. A more comprehensive model is under preparation. 23 refs., 10 figs., 4 tabs