Leaching behaviour of cementitious nuclear wasteforms containing caesium and strontium

The leaching behaviour and physicochemical properties of cementitious nuclear wasteforms containing caesium and strontium waste simulants has been investigated. The cement wasteform consisted of a 9∶1 blend of blast furnace slag and ordinary Portland cement. Both non-loaded samples and samples that were waste loaded with 3 wt-% caesium and strontium added as nitrates have been studied. The cement hydration phases in the samples were identified, and the porosity and microstructure were analysed before leaching. The samples were leached for up to 6 months and the leached elements quantified. In the waste loaded cements, portlandite was not formed, and the monosulphate AFm phase appeared to be altered by the incorporation of the Sr(NO3)2. Incorporation of Cs and Sr also resulted in the increase in the leach rate of Ca2+.