Fuel Recycling Feedback Control Via Real-Time Boron Powder Injection in East with Full Metal Wall

Abstract

The feedback control of fuel recycling through real-time boron powder injection, solving  the issue of the continuously increased recycling in long pulse plasma discharge, has been successfully developed and implemented in EAST. The feedback control system mainly includes four parts: the impurity powder dropper (IPD), diagnostic system measuring fuel recycling level represented by Dα emission , plasma control system (PCS) implementing the Proportional Integral Derivative (PID) algorithm, and signal converter connecting IPD and PCS. Based on this control system, both active control and feedback control experiments were carried out in EAST with full metal wall. The active control results show that the fuel recycling could be gradually decreased to a very low level with increased PCS control voltage. In feedback control experiments, it was also observed that the Dα emission was reduced below the target Dα value by adjusting boron injection flowrate, which indicates the fuel recycling feedback control was successfully achieved. The technique provides a potential new method for fuel recycling control of long pulse and high parameter plasma operation in future fusion devices.

Keywords: Fuel recycling, feedback control, boron powder, EAST