Fusion Science and Technology / Volume 37 / Number 2 / March 2000 / Pages 110-123
The planned Korea Superconducting Tokamak Advanced Research (KSTAR) divertor has been designed to provide reliable power handling and particle control with enough shaping flexibility to accommodate a wide range of plasma operation. The physics basis for the current configuration of the KSTAR divertor through analyses of the heat flux at the target, particle control, and plasma-facing component is reported. A simple zero-dimensional model based on the power balance assumptions and two-dimensional codes is utilized to estimate the heat flux to the divertor plate. The limit for the peak heat flux on the divertor plate, 3.5 MW/m2, requires advanced operating modes such as the radiative divertor and radiative mantle, which are considered to overcome the weakness of a high-recycling divertor. A simple particle balance model could estimate the pumping rate with total leakage fraction assuming particle sources. A Monte Carlo neutral transport calculation determines the dimension of a gap between the center and outer divertor targets. It also determines the number and best position of the pumps, as well as the geometry for conductance. For the initial 20-s discharges, a bolted-tile carbon-fiber-composite design is relied upon for the upper and lower divertor targets. The design of the supporting structure for the divertors will allow for future modifications to accommodate thermal steady-state 300-s operation or to optimize divertor performance based on new understanding gained during initial tokamak operation.