Plasma-facing component (PFC) materials directly affect tritium inventories by the creation of a characteristic set of volatile impurities inside the torus. Impurity creation processes were modeled and incorporated into the TritiUm Fusion Fuel cycLE dynamic Simulation, TRUFFLES, which simulates dynamic inventories in the tritium reprocessing systems.1 These surface processes include net erosion and “outgassing”. The estimated impurity outflow is coupled with the tritium reprocessing models in TRUFFLES to calculate inventories. Be and C were evaluated as examples of plasma-facing materials. It is found that for C a constraint limiting its net erosion rate is necessary in order to keep the tritium inventory in the cryopumps below a specified value. In contrast, Be may present no problem because of its non-production of volatile species when eroded during reactor power operation. “Outgassing” of H2O and the DT reflection coefficient were also investigated.