Stainless-steel specimens (15x15x0.5 mm(3)) containing homogeneously distributed tritium were used for the experiments. To investigate the fate of tritium in the surface region, about 70 mu m were chemically etched and the regrowth of tritium on the top surface layer determined as function of time by beta-ray-induced x-ray spectrometry. Simultaneously, the specimen was flushed with an argon gas stream at ambient temperature and the released tritium collected in water bubblers. The chronically liberated tritium retained in the bubblers was quantified in regular intervals using a liquid-scintillation counting technique. It was found to consist predominantly of tritiated water (99%); the rest probably being tritium-containing hydrogen. In this work, a model for the transport of hydrogen is proposed that allows quantitative evaluation of the experimental results. It is demonstrated that the numerical simulation accurately predicts the amount of tritium progressively trapped on the surface and that slowly released at ambient temperature from the bulk of the stainless-steel material. (c) 2008 American Vacuum Society.