Design and test of the KSTAR vacuum pumping system

The Korea Superconductor Tokamak Advanced Research (KSTAR) device is a tokamak mainly composed of a vacuum vessel, superconducting magnets, and cryostat. The internal volume of the vacuum vessel is about 110 m3 with a target pressure of 1 × 10−6 Pa, while the volume of the cryostat is 450 m3 with a target pressure of 5 × 10−3 Pa. To attain these target pressures, two identical vacuum pumping systems consisting of dry pumps, mechanical booster pumps, turbo-molecular pumps, and cryopumps were installed. The control system of the vacuum pumping systems was built using the experimental physics and industrial control system (EPICS), which has various merits such as easy access, convenient extension and flexible integration. The pump-down test of the pumping ducts was successfully executed under the control of the EPICS system.