Robust Burn Control of a Fusion Reactor by Modulation of the Refueling Rate

An integrated zero-dimensional plasma-control code, ASH, has been developed and employed to study the possibility of controlling the burn condition of a fusion reactor of the International Thermonuclear Experimental Reactor type by modulating the refueling rate. A constant-gain proportional feedback controller is synthesized; the values of feedback gains are obtained by either pole placement or an design. Compared with the use of modulated auxiliary heating alone, modulation of the refueling rate can provide important additional leverage in tokamak burn control. A key feature of this system is the incorporation of robust control theory to allow for modeling uncertainties.