Integrated power exhaust modelling for DEMO with lithium divertor

Abstract

A DEMO reactor with a liquid lithium divertor setup is considered. The simulation is performed for EU DEMO 2018 configuration using COREDIV code which self-consistently solves core and scrape-off layer transport equations for plasma and impurity. Influence of the sputtering, prompt redeposition and evaporation of the liquid lithium divertor was taken into account. Two operation regimes were identified. In the first regime evaporation rate is suppressed by the cooling system and is of the order of the sputtering rate. Scrape-off layer plasma characterises with low radiation and high total power to the plates. In the second regime the evaporation rate is much higher than the sputtering rate. High Li influx reduces temperature in the divertor region. Lithium radiation is increased reducing power to the plates. Plasma parameters in the core are comparable for the two regimes and the fusion gain parameter Q drops only slightly. Both regimes characterise with high plasma dilution. Power across the separatrix stays above the L-H threshold.