Development of Compact Reactor Use Cases to Inform Transport Studies

The OMFIT STEP integrated modeling workflow has been used to develop self-consistent core plasma use case scenarios for compact inductive and steady-state tokamak fusion reactors. The initial use cases target an up-down symmetric reactor able to produce 200 MW or more net electric power with B₀ = 8 T, R = 4 m, a = 1.4 m, elongation κ = 2, triangularity δ = 0.5, and Z_eff ~ 2. For this starting work, only the core plasma is modeled without inclusion of divertor or wall geometry, and only a simple model of electron heating and current drive sources is utilized. Starting from pedestal pressure predictions made with EPED, the workflow iterates between the CHEASE equilibrium solver, ONETWO transport code, and TGYRO transport solver to develop self-consistent core plasma scenarios. Both an inductive scenario with I_p = 16 MA, P_aux = 50 MW, q₉₅ ~ 4.9, f_bs ~ 0.3, β_N ~ 2.3, Q_fus ~ 25, H_98,y2 ~ 0.9 and steady-state scenario with I_p = 12 MA, P_aux = 95 MW, q₉₅ ~ 6.5, f_bs ~ 0.65, β_N ~ 3.2, Q_fus ~ 13, H_98,y2 ~ 1.3 are capable of meeting the power production goal for n_ped/n_GW ~ 0.8. Details of dominant transport mechanisms, as well as benchmarking of TGLF and CGYRO predictions for these parameters, will be presented.