Deuterium trapping in irradiated 316 stainless steel

Linear ramp thermal desorption measurements were conducted on 316 stainless steel samples implanted at 296 K with 1–10 keV D+ to fluences of 1017–1019 D+/cm2. Samples were held 1–100 h at 296 K prior to desorbing. The desorption data were shown to arise from two dominant mechanisms: bulk migration of mobile deuterium atoms with ~0.6 eV migration energy, and release from near surface traps with a net detrapping energy of ~0.9 eV. After 10 keV D+ bombardment, more complex desorption spectra were observed. Samples pre-damaged with 300 keV He+ exhibited a significant increase in the deuterium trapping compared to samples without pre-bombardment. Based on the data and modelling, estimates of tritium retention in TFTR were made.