Design of 4.5 K High Pumping Speed Cryo-Pump for China Fusion Engineering Test Reactor Torus

We reported the design and evaluation of a lab-built 4.5 K cryo-pump, capable of operating at a high pumping speed for pumping the torus chamber to the required high vacuum in China Fusion Engineering Test Reactor (CFETR) by timely removing neutral particles in plasma discharge.First, the condensing area was determined by calculating the effective pumping speed at the divertor's opening;second, the temperature distribution of the cryo-panel surfaces was simulated to verify the feasibility of the newly-designed cryo-pump by calculating the heat loads of cryo-panels and thermal radiation shields at steady operation;and finally, the overall layout and operation scheme of the cryo-pumps were established according to the pumping characteristics of the torus chamber.We suggest that the new cryo-pump be of some basic and technological interest in R&D of the subsequent test reactor.