(238b) Adsorption of Tritiated Water From Off-Gases From Spent Fuel Reprocessing Plants

Voloxidation is a promising process for the removal of >99% tritium from spent nuclear fuels prior to aqueous reprocessing. Tritium released from the voloxidizer to an off-gas stream is in the form of tritiated water vapor. The state-of-the-art of removal of tritiated water vapor from off-gases is adsorption on solid sorbents. Development of sorbents and sorption processes for off-gas treatment requires advanced predictive modeling tools for simulating dynamic adsorption processes. Development of modeling tools further requires fundamental experimental adsorption equilibrium and kinetic data. In this work, equilibrium and kinetics of water adsorption on zeolite 3A were studied in a continuous flow adsorption system at 25-80 ^oC over a wide range of water dew points from -70 ^oC to 10 ^oC. Adsorption isotherms were developed and isotherm behaviors different to previous studies were discussed. Adsorption kinetics was modeled using the linear-driving force (LDF) model and the shrinking-core model. It was found that both models could predict water adsorption loading curves and the LDF model performed slightly better.