Dynamic model of ITER Front-End Cryopumps Distribution System: Torus cryopumping and regeneration scenarios

•A dynamic model of the cryogenic distribution system of ITER torus cryopumps is developed.•The model results for a 100K regeneration cycle confirm the capability of the system to meet the pumping requirements for the 3000s plasma pulse.•The model allows the optimization of the system control and can enable a virtual commissioning useful to anticipate dynamic integration issues. The ITER vacuum system will use first of a kind cryopumps to provide high vacuum conditions to the torus vacuum vessel, the cryostat, and the neutral beam injectors. In order to evacuate the high gas flows required by the plasma scenarios, the cryopumps will need sequential regeneration with unprecedented high frequencies. The Front-End Cryopumps Distribution System, made of 12 cold valve boxes and 1 warm regeneration box, will provide helium to each of the cryopumps at the required pressure, temperature and mass flowrate, with dynamic synchronization with plasma pulses, in order to control the pumps behaviour during pumping and regeneration. A model of the cryopumps and their cryogenic distribution system is being developed, with the purpose of simulating the cryogenic process in dynamic scenarios and optimize the final design and the control of the system. This paper presents the dynamic model of the torus subsystem, made of 6 torus cold valve boxes, and the connected cryopumps, during operation and 100K regeneration scenarios. The preliminary simulation results will be presented, giving useful information for a refined setting of parameters like pressures, mass flow rates, and valves control. These results are suitable to be used to optimize the distribution system final design and commissioning.