Description
M. Kikuchi1,2,3, Dehong Chen4, Jiaxian Li2, Wulyu Zhong2
1. AAPPS-DPP, 2. Southwestern Institute of Physics, 3. ILE, the University of Osaka, 4. Institute of Plasma Physics, CAS
Negative triangularity tokamak[1] is an attractive advanced tokamak concept, which is proved to show significant plasma confinement relevant for fusion reactor with L-mode edge[2]. Based on recent developments of HTS magnet and well-documented Vector magnet design[3], we made a conceptual design of HTS-magnet based NT Tokamak Pilot Plant. Significant size reduction of tokamak machine is possible utilizing Bmax=20T HTS design.
Configuration design is made compatible with slim blanket/shield design and HTS magnet. Major parameters are Rp=3.64m, ap=1.4m, Bt=6.33T, Ip=15MA, x=2.0, u/L=-0.4/-0.9, q95=3.3 for inductive operation and 12MA for steady-state operation. PF coil system inside TF coils will utilize Cu and SC hybrid magnets. Equilibrium calculation shows such equilibrium control is possible as well as flux-tube expansion near the divertor target.
Preliminary system code survey compatible with NT shape shows Pfusion=500MW, PNB=50MW, Q=10 for inductive operation and the steady state Q=5, Pfusion=500MW is possible for Ip=12MA with PNB=100MW.
This machine could cover most of ITER technical objectives with significantly lower cost and could test robust ELM-free high confinement based on NT tokamak concept.
Additionally, this machine will also allow fusion power exhaust and handling with high temperature blanket while small area in the inboard side may not be covered by the blanket. Blanket installation in NT configuration will prove better blanket realizability than PT compact reactor since more space is available.
Design of radial build is key for the high field compact fusion pilot plant. Distance between TF and plasma surface is 96cm. Installation of Cu CS coils inside TF coils may limit slim shield/blanket width of 60cm at midplane.
[1] M. Kikuchi, et al., L-mode-edge negative triangularity tokamak reactor, Nucl. Fusion 59(2019)056017
[2] M. Austin, et al., Achievement of Reactor-Relevant Performance in Negative Triangularity Shape in the DIII-D Tokamak, PRL 122(2019)115001
[3] T. Ando, S. Nishio, Design of the TF coil for a tokamak fusion power reactor with YBCO tape superconductors, Fusion technology(2006)