Volume changes of cement composites for evaporator concentrates immobilization

Evaporator concentrates as an intermediate-level radioactive waste have to be safely disposed in a suitable safe repository. Therefore, a durable matrix as a part of a multi-barrier system is needed for solidification and immobilization of such waste. The article compares different mixtures proposed for EC immobilization in terms of volume changes and mechanical properties. High water-binder ratio does not favor any of these properties, but it is needed to achieve the highest possible volume fraction of immobilized waste. In terms of both volume changes and mechanical properties sulpho- aluminate cement-based composite (SAC) showed superior behavior in comparison to all other studied composites. However, SAC is known to be susceptible to temperature-induced changes and thus its durability may be diminished which is at focus of the ongoing research.