Abstract
Recent progress(1) in plasma science of the Spherical Tokamak (or Spherical Torus, ST)(2) has indicated relatively robust
plasma conditions in a broad number of topical area including strong shaping, stability limits, energy confinement, self-driven
current, and sustainment. This progress has enabled an extensive update of the plasma science and fusion engineering conditions
of a Component Test Facility (CTF)(3), which is potentially a necessary step in the development of practical fusion energy. The
chamber systems testing conditions in a CTF are characterized by high fusion neutron fluxes Γn > 4.4×1013 n/s/cm2, over sizescale
> 105 cm2 and depth-scale > 50 cm, delivering > 3 accumulated displacement per atom (dpa) per year(4). Such chamber
conditions are calculated to be achievable in a CTF with R0 = 1.2 m, A = 1.5, elongation ~ 3, Ip ~ 9 MA, BT ~ 2.5 T, producing a
driven fusion burn using 36 MW of combined neutral beam and RF power. The ST CTF will test the life time of single-turn,
copper alloy center leg for the toroidal field coil without an induction solenoid and neutron shielding, and require physics data on
solenoid-free plasma current initiation, ramp-up, and sustainment to multiple MA level. A new systems code that combines the
key required plasma and engineering science conditions of CTF has been prepared and utilized as part of this study. The results
show high potential for a family of relatively low cost CTF devices to suit a range of fusion engineering science test missions.