A final report on hydrothermal testing of sup 99 Tc-doped glass waste form and waste package components

This document reports the results of four experiments using borosilicate glass doped with the key radionuclide {sup 99}Technicium. The experiments were performed in Dickson rocking autoclaves at 200{degree}C, 30MPa pressure for 3 months. Starting materials consisted of the doped glass (+ undoped borosilicate glass){center dot} in GR-3 groundwater. To simulate various possible interactions among waste package components, the glass-groundwater starting materials were run either alone, or combined with RUE-basalt, or cast steel or both. The Dickson autocalve allowed periodic sampling of the fluid, through which concentrations of dissolved species were monitored. In the glass-only experiment, Tc concentration increased until reaching an apparent steady-state concentration of 55 mg/1 after 1000 hours. In runs with basalt, steel or both, this concentration reached steady-state at three or more orders of magnitude below that. 29 refs., 23 figs., 8 tabs.