Experimental study and modelling of deuterium thermal release from Be–D co-deposited layers

A study of the thermal desorption of deuterium from 1 µm thick co-deposited Be–(0.1)D layers formed at 330 K by a magnetron sputtering technique is reported. A range of thermal desorption rates 0 ⩽ β ⩽ 1.0 K s−1 are explored with a view to studying the effectiveness of the proposed ITER wall and divertor bake procedure (β = 0 K s−1) to be carried out at 513 and 623 K. Fixed temperature bake durations up to 24 h are examined. The experimental thermal release data are used to validate a model input into the Tritium Migration and Analysis Program (TMAP-7). Good agreement with experiment is observed for a TMAP-7 model incorporating trap populations of activation energies for D release of 0.80 and 0.98 eV, and a dynamically computed surface D atomic to molecular recombination rate. (paper)