A growth/annealing equilibrium model for helium-induced nanostructure with application to ITER

摘要: Abstract It is now well-known that under exposure to a helium (He) plasma at elevated temperatures, tungsten (W) surface modified by the growth of fibreform nano-structure referred as “fuzz”. Formation W fuzz occurs when specific set conditions are met and raises concerns for behaviour ITER divertor targets. The key open question remains, however, whether or not will actually form in ITER. An analysis existing data shows annealing kinetics can be described diffusive-like law. A growth/annealing equilibrium model then proposed take into account Edge Localized Mode (ELM)-induced erosion effect transient temperature excursion on annealing. In addition, both decrease rate thermal conductivity with increasing thickness treated consistently. main finding grows thicker, its decreases peak attained during an ELM increases. Given competition between rates, exists above which dominates given energy density. absence ELMs, would increase typical t0.5 time dependence.