Complex multi-dimensional modelling of hydrogen transport in ITER and WEST plasma facing components

Abstract : Understanding hydrogen isotopes transport in plasma facing components is crucial for tokamak operation and for safety issues. Numerical modelling is often required and can be complex when applied to multi-material environments with complex interfaces and geometries (2D/3D). This is the case for many plasma facing components such as the monoblocks that will be used in the divertor of present and future fusion reactors like WEST and ITER. To this day, few studies have simulated hydrogen transport and retention in these components with relevant physics and geometries. To simulate these processes, a finite element modelling code called FESTIM has been developed [1]. FESTIM can perform complex multidimensional simulations with several materials. The code also simulates heat transfer in solids to take into account the non-homogeneous temperature field induced by the non-homogeneous heat flux and by the cooling system. FESTIM has been used to estimate the hydrogen inventory in the ITER divertor with different exposure conditions such as surface temperature and surface hydrogen concentration using machine learning algorithm. The aim of this study is to apply the same methodology to the WEST tokamak using SOLEDGE3X-EIRENE plasma backgrounds in various divertor operational regimes (density scan, power scan). In addition, several ITER operation cases are examined.