Plasma-facing materials for fusion devices

Retention and enrichment of tungsten-containing carbon films under deuterium beam impact

“…D into depth at 300 K is not different between a C material, which exhibits a graphite structure (pyrolytic graphite), and a C material, which exhibits an amorphous structure (a-C). Furthermore, the diffusion of D into depth is not affected by the W inclusions and thus by a changed trapping behaviour observed in a-C:W. By extrapolating the increase of the hydrogen inventory with fluence according to Φ X (with X = 0.1 at 300 -500 K) it can be shown that even after 0.5·10 5 400 s ITER-discharges in the T burning phase, which fits the scheduled operation time of the T burning phase of 20 years, the T inventory in a-C:W -built up by implantation and diffusion into depth -is at 300 -500 K two orders of magnitude below the safety limit of 700 g. This confirms that the build-up of the T inventory through the use of CFC is dominated at 300 -500 K by the co-deposition of T and C in remote areas, as already well known in literature [4,20,52].…”

Deuterium-ion implantation into composite structures with tungsten coatings

“…According to [1][2][3], tungsten is thought to be one of the most promising protective materials for the devices of thermonuclear reactors (TNR) that contact with plasma. An advantage of tungsten using is the negligible accumulation of hydrogen isotopes in this material.…”

Modelling of hydrogen isotope inventory in mixed materials including porous deposited layers in fusion devices

“…The heating module is applied here to a Be/C/W materials wall, where the heating conductivity data is obtained from [26,27]. The wall thickness (distance of surface to the cool side) is L. The coolant temperature is fixed to T 0 = 400 K.…”

“…where ρ and C p are the density (kg/m 3 ) and specific heat (J/(kg · K)) of the materials, respectively, and k(T ) = 1/(aT + b) is the heat conductivity (W/(m · K)), where the constants a and b are fitted from experiments [26]. The fitted form of k(T ) is used for convenience, as it allows an analytic solution at steady-state for simple cases, but is not an absolute requirement.…”

“…We present here a Hydrogen Isotope Inventory Processes Code called HIIPC, in which a particle balance model for reaction-diffusion and inventory of HI in metals [17] and porous media based on Ref. [25] has been developed At the current stage, the model (HIIPC) includes three parts: a 1D heating module for the temperature distribution in the wall [26]; a metal module for HIIPs in metal materials (tungsten and beryllium), and a four region module for HIIPs in porous media (CFC and co-deposited layer). The goal of this standalone model is to provide a functional module for present fusion simulation codes and to furnish them with a capacity to take into account HIIPs in PFCs.…”