(446b) Temperature Comparisons of Cesium Ion Exchange Performance with Crystalline Silicotitanate on Hanford Tank Waste

Crystalline silicotitanate (CST) ion exchanger is planned to be used to remove cesium (¹³⁷Cs) from the aqueous phase of Hanford tank wastes in preparation for vitrification at the Waste Treatment and Immobilization Plant (WTP). The average bulk supernate temperatures of the majority double-shell tanks (DSTs) in the Tank Farms currently average around 16 °C during the spring and winter months. Column and batch contact testing with simulants and actual tank waste were conducted at temperatures between 16 °C and 35 ºC to test the impact of operating temperature on ion exchange processes. With a decrease in temperature, CST capacity for Cs increased while the kinetics of the exchange decreased. Based on these results, a determination of temperature impacts on overall mass transfer will allow future modeling of breakthrough performance at a range of process conditions.