The Helium Cooled Pebble Bed breeding blanket of the EU-DEMO foresees continuous processing of a small fraction of the helium coolant in the coolant purification system (CPS) to counteract buildup of tritium and impurities. For this system, two different process variants are currently considered. The first is based on the conversion of all hydrogen species into water using copper oxide beds and the subsequent water adsorption over zeolite molecular sieve (ZMS) beds. The alternative process foresees the direct sorption of hydrogens onto novel ZAO® non-evaporable getter (NEG) materials. The ZMS beds and the NEG beds are operated batchwise, but alternating schemes with an absorption (operation) phase and a desorption (regeneration) phase result in a pseudocontinuous process. Transient process simulations have been developed to evaluate the performance and impact of the different variants on downstream systems in the fuel cycle. In this contribution, these process models for the preconceptual design of both variants are presented and evaluated. For the reference designs proposed for each system, they have been found to satisfy the requirements of achieving 90% efficiency. This modeling then lays the foundation for optimization of the conventional process and outlines further research demand regarding the application of NEG materials needed to progress toward the concept design of the CPS process.