TOWARD A CONSISTENT MODEL FOR GLASS DISSOLUTION

Understanding the process of glass dissolution in aqueous media has ad vanced significantly over the last 10 years through the efforts of man y scientists around the world. Mathematical models describing the glas s dissolution process have also advanced from simple empirical functio ns to structured models based on fundamental principles of physics, ch emistry, and thermodynamics. Although borosilicate glass has been sele cted as the waste form for disposal of high-level wastes in at least 5 countries, there is no international consensus on the fundamental met hodology for modeling glass dissolution that could be used in assessin g the long term performance of waste glasses in a geologic repository setting. Each repository program is developing their own model and sup porting experimental data. In this paper, we critically evaluate a sel ected set of these structured models and show that a consistent method ology for modeling glass dissolution processes is available. We also p ropose a strategy for a future coordinated effort to obtain the model input parameters that are needed for long-term performance assessments of glass in a geologic repository.