Integrated dissipative SOL solutions for a net electric 200MW steady-state Fusion Pilot Plant

A core-edge integration study has been conducted for a steady-state Fusion Pilot Plant producing 200MW of net electric power with a single lower divertor (R= 5 m, B₀ = 6 T, I_p= 8.5 MA). A set of steady-state integrated dissipative SOL plasma solutions with krypton seeded impurities have been obtained with SOLPS-ITER without ExB drifts, and using radial transport coefficients profiles that reproduce H-mode density and temperature profiles experimentally observed in tokamaks. The resulting heat flux width is of the order of 2 mm as predicted by the Fedorczak-Peret scaling law [1]. Magnetic equilibrium, pedestal density (n_e,ped=10²⁰m^-3) and pedestal power (P_sep=75MW) used in SOLPS-ITER simulations have been obtained with the Fusion Energy Synthesis Engine (FUSE) [2] assuming in the core region. The separatrix operational space has been explored by varying D₂ and Kr puffing rates, showing that detached divertor plasma can be systematically achieved for separatrix density that remains well below the Greenwald fraction limit (f_GW<0.6) and impurity content at the pedestal compatible with core plasma assumptions (Z_eff,ped < Z_eff,core). A scaling law for the concentration of seeded impurity necessary to achieve detachment has been derived, showing that c_z ∝ P_SOL^1.56 n_e,_sep^-3.36 in line with experimental observations in AUG [3].

[1] M. Peret et al, , “Predictive turbulence-driven flux model of scrape-off layer widths across confinement regimes in tokamaks”, this conference

[2] O. Meneghini, et al., Proceedings of the IAEA FEC 2023 Conference, 2023.

[3] Henderson, Stuart S., et al. Nuclear Materials and Energy 28 (2021)