Assessment of erosion and tritium codeposition in ITER-FEAT

Erosion of the first-wall and divertor, and distribution of eroded material in combination with tritium codeposition (primarily with eroded carbon) over many pulses, remain critical issues for the design, operation, and safety of a long-pulse next-step fusion device, such as ITER. These issues are currently being investigated by experiments in tokamaks and in laboratories, as well as by modelling. In this study, we analyse erosion (e.g., by sputtering, ELMs, and off-normal transients) and codeposition effects in the reduced-size ITER device, called `ITER-FEATʹ, with a strike-point carbon divertor target and metallic walls, for a `semi-detachedʹ edge plasma regime using two-dimensional profiles of plasma edge parameters, modelled by the code B2-EIRENE. This paper accompanies the overview paper given by G. Janeschitz et al. [Plasma wall interactions in ITER-FEAT, these Proceedings]. Tritium codeposition with chemically eroded carbon still presents removal/control challenges, albeit to a somewhat lesser extent than in the 1998 ITER design, and demands efficient tritium inventory removal/control techniques. Due to numerous model uncertainties, not the least of which are the plasma solutions themselves, our intent is to provide a scoping analysis, defining trends and suggesting further research needs.