Dissolution of simulated nuclear waste glass at high surface area to solution volume, high pH and 70 °C: comparison of international simple glass and SON68 glass.

Long-term static dissolution experiments, lasting up to ∼1500 days, were conducted on International Simple Glass (ISG) and SON68 glass under hyperalkaline pH, at 70 °C, and at a very high glass surface area to solution volume ratio. The study compared (1) glass dissolution kinetics, (2) secondary phase formation, and (3) the microstructure of the altered glass and secondary phase interface. Boron release indicated rapid initial dissolution followed by a slowdown mainly due to a significant pH drop.

A high-resolution non-invasive approach to quantify oxygen transport across the capillary fringe and within the underlying groundwater.

Oxygen transport across the capillary fringe is relevant for many biogeochemical processes. We present a non-invasive technique, based on optode technology, to measure high-resolution concentration profiles of oxygen across the unsaturated/saturated interface. By conducting a series of quasi two-dimensional flow-through laboratory experiments, we show that vertical hydrodynamic dispersion in the water-saturated part of the capillary fringe is the process limiting the mass transfer of oxygen.