Skin-contact exposure to tritium-gas-contaminated stainless-steel surfaces

One of the radiation protection problems potentially encountered in tritium-handling facilities is contamination of metal surfaces. Experiments with hairless rats have demonstrated that when intact skin is brought into contact with tritium-gas-contaminated stainless-steel surfaces, tritium can be fixed as organically bound tritium (OBT) and as tritiated oxide (HTO) in the skin. The radiological hazard associated with this route of tritium uptake is determined by the retention and distribution of tritium in the skin and other organs. The experimental data suggest that the OBT in the skin serves as an input source to the rest of the body. The urinary excretion of tritium shows a biphasic excretion for OBT and a single-phase clearance for HTO from the body. The results indicate that the exposure from this mode of contamination results in long retention of tritium in the skin as well as in non-uniform distribution of tritium in organs and macromolecules. This information is useful in evaluating the possible dosimetric concerns from this mode of exposure.