Flow-induced structure in a system of nuclear waste simulant slurries

Thixotropy and antithixotropy were characterized in nuclear waste simulant slurries. For the neutralized current acid nuclear waste (NCAW) simulant slurries, NCAW with glycolic acid (NCAW+GA), and NCAW with nitric acid (NCAW+NA) (pH 4), a pre-shear flow at constant shear rate destroys the aggregates in the suspension and reduces viscosity. For the NCAW+NA (pH7–9), a pre-shear enhances the aggregates in the suspension and increases viscosity. With the addition of silica to the NCAW+GA and NCAW+NA slurries, the pre-shear effect tends to promote aggregation due to the formation of a network in the suspension, and hence, the viscosity increases. The macroscopic rheological property variation due to the microstructural aspects of the suspensions associated with the shear-induced effect are addressed.