Divertor power spreading in DEMO reactor by impurity seeding

Highlights: • The COREDIV code has been used to simulate DEMO inductive discharges with different impurity seeding (Ne, Ar, Kr) and different sputtering models (with and w/o prompt re-deposition process). • It has been shown that only for Ar and Kr seeding it is possible to achieve H-mode plasma operation with acceptable level of the power to the tungsten target plates. • For neon seeding, such regime of operation seems not to be possible. • Prompt re-deposition model extends the DEMO operation window. - Abstract: Numerical simulation with COREDIV code of DEMO H-mode discharges (tungsten divertor and wall) are performed considering the influence of seeding impurities with different atomic numbers: Ne, Ar and Kr on the DEMO scenarios. The approach is based on integrated numerical modeling using the COREDIV code, which self-consistently solves radial transport equations in the core region and 2D multi-fluid transport in the SOL. In this paper we focus on investigations how the operational domain of DEMO can be influenced by seeding gasses. Simulations with the updated prompt re-deposition model implemented in the code show that only for Ar and Kr, for high enough radial diffusion in the SOL, it is possible to achieve H-mode plasma operation (power to the SOL> L-H transition threshold power) with acceptable level of the power to the target plates. For neon seeding such regime of operation seems not to be possible.