Effect of Platinoids on French LWR Reference Glass Properties

Abstract

ABSTRACTNine samples of the “R7T7” glass composition selected to vitrify fission product solutions in France were prepared with added platinoid elements (ruthenium, rhoditun and palladium) in soluble form and as insoluble metal particles in solution, and their major properties were measured. Regardless of the initial form when added to the glass the platinoids always formed the same heterogeneous inclusions in the final glass: RuO2 precipitates which were often found as aggregates, and polymetallic (Pd, Rh & Te) inclusions.The particles tended to settle in the molten glass. The viscosity increased by about 20% at 1100°C. The mechanical properties and short-term leach rates were not significantly affected. Crystallization increased by a factor of 2 or 3 in heat-treated glass specimens but did not exceed a few volume percent. However, as the short-term leach rate did not significantly increase, the glass properties were very satisfactory.