Fuel inventory and material migration of JET main chamber plasma facing components compared over three operational periods

Abstract

Fuel retention and material migration results from JET ITER-like wall beryllium limiter tiles are presented for three operating periods. Ion beam analysis results support the general picture of erosion during limiter configurations with local deposition on tile ends far into the scrape off layer. Similar trends of fuel concentrations are observed in all JET operating periods; (i) low on surfaces exposed to high heat flux and erosion and (ii) higher in deposits. The pattern of fuel retention and deposition correlates with heat flux and distribution of limiter plasmas touching inner and outer limiters. The D/Be ratio in the thickest deposit is ∼0.01. Global fuel retention attributed to limiters is <0.01% of injected fuel. Marker coatings reveal a rapid transition from strong erosion to deposition within 15 mm. This work highlights the need to carefully consider the requirements of marker coatings for long exposure studies in high erosion areas.