Assessment of Operational Space for Long-pulse Scenarios in ITER

摘要

Introduction Straightforward transport calculations suggest a certain chosen transport model for a chosen set of actuators, current, I_p density, n and input power, P_(aux). To provide energy multiplication Q = P_(fus) /P_(aux)≥ 5 for long pulse (LP), ?t = 1000 s hybrid and steady-state (SS) operation [1] with configuration of heating and current drive systems (H&CD) designed for ITER [2] high pedestal pressure and improved core confinement are typically assumed [3]. It remains unclear whether the obtained operational points (OPs) are unique or optimal, what improvement of confinement is needed if any, how to provide operation within the design and physical limits. To clarify these issues we propose for ITER analyses the inversed transport task (ITT) approach. The ITT assumes that the set and configuration of the H&CD systems is already specified, P_(aux) = ∑ P_k, (P_k: P_(NbI) = 33 MW, P_(EC) = 20 MW, P_(IC) =20 MW) and there is no synergism between them. Then, using CD efficiencies calculated by codes validated versus experiments [6] we define the confinement required for LP and SS operation and operational space (OS), i.e. the range of actuators, I_p, n, P_k where such operation is possible within the design and physical limits.