Predicting liquid immiscibility in multicomponent nuclear waste glasses

Taylor`s model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the US Department of Energy`s Hanford site. Taylor`s model is primarily based on additions of modifying cations to a Na{sub 2}O-B{sub 2}O{sub 3}-SiO{sub 2} (NBS) submixture of the multicomponent glass. The position of the submixture relative to the miscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor`s, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li{sub 2}O to the ``alkali`` corner of the NBS submixture.