Improved tritium retention modeling with reaction-diffusion code TMAP and bulk depth profiling capability

Abstract ITER-grade tungsten (W) specimens were exposed to similar deuterium (D) plasma condition (ion flux density of 6.0 × 10 21 D m − 2 s −1 , D ion fluence of 5.0 × 10 25 D m − 2 ) at the surface temperature of 623 K. Thermal desorption spectroscopy was used to measure total D retention in one W specimen after D plasma exposure. Glow-discharge optical emission spectroscopy was used to measure D depth profiling from the other W specimen exposed to the similar condition, and deep D trapping up to 25 μm was observed. When the normalized D depth profile was used with a reaction-diffusion code TMAP7 to model experimental D desorption behavior, an excellent agreement to experimental results was achieved. The modeling results suggested that the predominate mechanism of the deep D trapping might be D trapping in intrinsic intergranular cracks in ITER-grade W.