The results of previous work (Baldwin et al 2013 J. Nucl. Mater.438 S967–70 and Baldwin et al 2014 Nucl. Fusion54 073005) are extended to explore the influence of layer thickness on the thermal D2 release from co-deposited Be–(0.05)D layers produced at ∼323 K. Bake desorption of layers of thickness 0.2–0.7 µm are explored with a view to examine the influence of layer thickness on the efficacy of the proposed ITER bake procedure, to be carried out at the fixed temperatures of 513 K on the first wall and 623 K in the divertor. The results of experiment and modelling with the TMAP-7 hydrogen transport code, show that thicker Be–D co-deposited layers are relatively more difficult to desorb (time-wise) than thinner layers with the same concentrations of intrinsic traps and retained hydrogen isotope fraction.
In-vessel surface layer evolution during plasma–wall interaction in the Globus-M spherical tokamak