Long Pulse ITER Scenarios and Control on KSTAR

e long pulse Korea Superconducting Tokamak Advanced Research (KSTAR, in South Korea) provides key opportunities for the United States (U.S.) collaboration to enable study and optimize ITER scenarios and control issues in a long pulse device with a tungsten divertor and reactor-relevant constraints of distant superconducting coils and a tungsten divertor. The project will be led by GA and performed by a team comprised of researchers from GA, PPPL, Lehigh, and ORNL. It will focus on improvement, demonstration and prediction of key ITER Q=10 scenarios on KSTAR, while qualifying ITER control solutions for disruption-free operation consistent with long pulse requirements. This research will advance U.S. leadership in areas critical for reliable operation and success for ITER, and help to position the U.S. for a key role in ITER scenarios and control. Studies of candidate Q=10 scenarios on short pulse devices have been largely limited to discharge durations comparable to or less than a resistive relaxation time. Qualification of ITER inductive scenarios on existing long pulse devices (i.e., for many resistive relaxation times and approaching or exceeding wall particle equilibration times) should minimize the need for iterative scenario development on ITER, and reduce schedule risk for the ITER program. Many control solutions needed to sustain these scenarios are being developed on short pulse devices and require extension to long pulse. Making use of achievements from previous efforts on KSTAR and DIII-D, this project will improve and extend KSTAR's ITER Q=10 Baseline Scenario, study of ITER-like ramp-up and ramp-down, and develop the control for extending the Advanced Inductive 'Hybrid' scenarios on KSTAR to the ITER shape. Enabling and supporting control solutions for scenario maintenance and disruption-free operation will be synergistically developed to aid in the scenario development and produce critical control tools for ITER. Simulations and real-time control algorithms will be developed and qualified for ITER scenario planning and optimization on KSTAR, including demonstration of gain-control during long pulse operation, assessment of effects on performance and scenario access with the new tungsten divertor, qualification of ITER continuous control and Exception Handling (EH) algorithms, development of response models and control solutions for scenario control, and the development of robust real-time disruption avoidance and prevention tools.