(738f) Rheological Modification On Nuclear Waste Simulant Slurries: Correlation Between Physicochemical Characteristics and Rheological Modification

Understanding and controlling rheological properties of slurries has been one of the most challenging problems in many industries. For nuclear waste treatment at the Hanford and Savannah River sites, it is extremely challenging due to the wide distribution of particle size, chemical species, and mass/volume fraction of particles. Operation of the waste treatment facilities at increased solids loading reduces the evaporative load on the melter systems and thereby increases waste processing rates. However, a higher solids loading creates significant processing issues associated with rheological properties. Controlling rheological properties allows for sustainable operations at higher solids loading and therefore reduces the operational cost and increases the waste processing rates. The use of several rheological modifiers over different nuclear waste simulant slurries has been investigated to address this issue. Using rheological analysis, it was found that weak organic acid type rheological modifiers (e.g., citric and polyacrylic acids) are generally good rheological modifiers. More importantly, the performance of rheological modifiers was found to be dependent on a coupled interplay between physicochemical parameters. More in-depth physical insights on the rheological modification will be discussed.