Conceptual study of the cryocascade for pumping, separation and recycling of ITER torus exhaust

For compliance with the pump requirements of ITER operation a concept of a universal pumping system has been studied. Compact pump trains for installation into pumping ducts are proposed consisting of primary and secondary pumps. The primary pump to be applied in the molecular flow range has a required pump entrance surface of 0.24 m2. To maintain divertor pressures, adjustable throttle valves are planned to be installed in front of the primary pumps. Separation of the gas species takes place in the secondary pumps which are operated in the viscous flow range. The impurities and fuel (D-T) with protium and helium are pumped subsequently into three individual chambers which can be isolated from each other during regeneration. For the secondary pump a diameter of 220 mm and a length of less than 1 m are required.