Chemical and thermal performance of crystalline silicotitanate (CST) and resorcinol-formaldehyde (RF) ion exchange columns are modeled for configurations that fit inside Savannah River Site waste tanks. Good cesium removal is predicted for both media. More waste can be processed per cycle with CST. Unlike RF, CST is not elutable and requires lead column replacement after each cycle. RF is subject to chemical and radiolytic damage reducing capacity each cycle. Fast cesium loading kinetics for RF allows minimization of exposure. Modeling shows that the baseline cooling system provides adequate cooling to maintain columns within process limits and indicates that removal of the outer cooling jackets may be possible.