The integration and tests of the shattered pellet injection system on EAST

Abstract

A SPI system specifically designed for EAST has been integrated and commissioned to carry out plasma rapid shutdown. This system is capable of injecting pellets with quantities ranging from 7 to 14 Pa m3 and at velocities between 150 and 400 m/s, as determined after conducting a series of bench tests. A two-stage differential pumping system designed to remove the propellant gas has had its efficiency assessed through the application of pumping equations and the fourth-order Runge-Kutta routine. For the purpose of facilitating remote control of the SPI system, a control system based on EPICS has been developed. This system enables an automated workflow for pellet formation and launch, which includes stages such as pellet formation, strengthening pellet, awaiting trigger, launching pellet, baking gun barrel, and cooling cold head, with the entire process taking 600 s. Furthermore, rapid shutdown experiments using Ne shattered pellet injection have been conducted, demonstrating the system's high reliability and reproducibility on EAST.