A compact advanced tokamak for a steady state fusion pilot plant

First of a kind physics based simulations project a compact 200MW net electric fusion pilot plant is possible at a modest ~4m radius scale, based on the advanced tokamak concept and a new integrated 1.5D core-edge modeling approach. Such a device would prove that fusion can make energy and could address nuclear science and tritium breeding missions in a phased research program to establish the basis for future commercial fusion power plants. These new simulations provide additional insights compared to previous “systems code” projections by self-consistently applying transport, pedestal and current drive physics models to converge fully non-inductive stationary solutions without any significant free parameters. Increasing plasma density, pressure and toroidal field are found to lower auxiliary heating and current drive demands leading to high (~90%) bootstrap current fraction solutions (Fig. 1 and 2). In these simulations, remaining current drive is provided by neutral beams and helicon ultra-high harmonic fast wave (Fig. 3), though other options exist. An important aspect is good current drive efficiency and confinement in reducing required fusion power and device scale. The low recirculating power needs lead to tolerable divertor and neutron wall loading, with radiative solutions maintaining good H mode access (Fig. 4). A bucking approach of the TF off the central solenoid combined with a central plug reduces mechanical stress. The concept would benefit from high temperature demountable superconductors. Thus the compact approach poses a research challenge to develop more advanced science, technology and engineering approaches but offers the prospect of a lower capital cost facility to more rapidly enable the leap to fusion energy.