Contamination of Stainless Steel Type 316 by Tritium

Tritium distribution in stainless steel type 316 exposed to hydrogen containing 32% of tritium at room and elevated temperatures was studied using thermal desorption, analysis of bremsstrahlung spectrums and acid etching techniques. All samples exhibit a large fraction of the overall tritium inventory concentrated in a thin sub-surface layer of ≈15µm thickness, where tritium concentration is by ≈2 order of magnitude larger than that in the bulk. Observed tritium depth profiles are in contradiction with a classical mechanism of hydrogen penetration to metals by atomic diffusion.