Design Proposal For MITICA Cryogenic Plant

The MITICA Neutral Beam Injector, under construction in Padua at Consorzio RFX, will be equipped with a large cryosorption pump (composed by two halves). The cryopump, installed inside the MITICA Beam Line Vessel, will be supplied by a dedicated cryogenic plant with gaseous Helium (GHe) at 80 K and super critical Helium (ScHe) at 4.6 K. The design proposal for MITICA cryogenic plant is described in this paper. The cryogenic plant is divided in two main closed circuits: the 4.6 K circuit and the 80 K circuit. The first one is supplied by a Helium refrigerator via a LHe control cryostat acting as a thermal buffer due to the variable pulsed heat loads expected during MITICA operation. The second circuit is supplied by an 80 K facility where the refrigeration power is given by liquid nitrogen (LN2). Due to the expected large LN2 consumptions, a Nitrogen refrigerator is foreseen to recover and re-liquefy the evaporated LN2.