document: Although the presented model is developed and tested with a-C:H layers in mind, it is not necessarily limited to them. Moreover, the only assumptions are chemical reactions between the gas and the solid forming volatiles, the loss of these volatiles from the material and the two stated boundary conditions of gas influx at a single outer surface and the possibility of reactions throughout the bulk. Porosity and significant gas inventories were observed not only for carbon [12] but, e.g. also for beryllium co-deposits [25] and can be expected for other co-deposits formed in plasma devices [1]. Thus, TCR and its description by the presented model may be applicable to all deposits. If a layer has constituents that are not forming volatiles with the reactive gas, e.g. W and Be with O2, these constituents cannot be removed by TCR, as they will not be removed from the deposit. This can influence the removal of other deposit constituents and the time evolution of the process can change. The new understanding of TCR may, for the first time, allow applying the method in a controlled way to nuclear fusion devices, possibly solving the tritium retention issue especially related to carbon based materials.
extractive_keyphrases: carbon chemical reactions constituents that are not forming volatiles with the reactive gas deposit constituents gas nuclear fusion devices plasma devices porosity reactions single outer surface solid forming volatiles tcr tritium w and be with o2
abstractive_keyphrases: a-c:h layers beryllium co-deposits carbon based materials gas influx gas inventories reactive gas tritium retention tritium retention issue