Analysis of the influence of the different impurity seeding on the burn-up fraction and plasma confinement in the EU DEMO reactor

Abstract

Abstract This work describes integrated numerical modelling applied to DEMO discharges with tungsten wall and divertor, using the COREDIV code, which self-consistently solves 1D radial transport equations of plasma and impurities in the core region and 2D multi-fluid transport in the SOL. The model is self-consistent with respect to both the effects of impurities on the α-power level and the interaction between seeded (Ar, Kr and Xe) and intrinsic impurities (tungsten, helium). This work is to analyse the influence of the impurity seeding on the burn-up fraction and plasma confinement in EU DEMO reactor. For the simulation with constant electron density at the separatrix, it is found that impurity seeding has a small influence on the burn-up fraction, which remains around 6 – 7%., but fuelling source is reduced from 2.7 to 2 × 1022 1/sec when moving from lowest to highest seeding level. The degradation of confinement for high Z seeding impurity, which is correlated to radiation in the core (due to seeded Kr and Xe) is observed. Better confinement for Ar at middle and high seeding level is observed in comparison to the case without seeding, because Ar radiation is small in the core (about 40-55 MW).