An automated liquid nitrogen refilling system for cryopumps in the 1-MW heating neutral-beam injector of the TCV tokamak

Abstract

A system for automated liquid nitrogen refilling of cryopumps in the neutral beam injector of the TCV tokamak (Switzerland) is described. The system includes industrially produced temperature and level monitors for cryogenic liquids, as well as an intelligent controller developed by the Budker Institute of Nuclear Physics on the basis of a field programmable gate array. The controller is used to control refilling of two cryopumps connected to a common nitrogen line and prevent emergency situations without operator attendance. Additional protection is ensured by the “timeout” mechanism used in different phases of the refilling cycle. The communication interface is available, and the user software is developed.