Conceptual design of Integrated Bivalent Auxiliary System (SABI) supporting the MITICA cooling plant and cryogenic plant

Abstract

The first ever built full-scale prototype of the ITER heating neutral beam injector is the MITICA experiment at PRIMA Neutral Beam Test Facility, under realization in Padova, Italy.This experiment consists of several in-vessel components: most of them are actively cooled by a large Cooling Plant, still under construction. Coolant is deionized water produced by a Chemical Control System (CCS).In the PRIMA facility, a cryogenic plant (currently in manufacturing phase) is also foreseen to serve the cryopumps to be installed in the MITICA Beam Line Vessel.During the installation of cooling plant and the design phase of cryogenic plant, two different issues came into evidence: waste water (produced by the CCS during operations) could not be delivered directly into the public network and the warm compressor of the cryogenic plant, originally air-cooled, changed to a water-cooled system.For the first issue the solution was found in a Water Treatment Unit (WTU) that requires the supply of hot water to distil the wastewater and to concentrate it.The second issue and the need to balance the heat loads and the cost and space constraints lead to an innovative system: it is essentially based on a high temperature water-water heat pump, by means of which the heat rejected by the warm compressor is used to heat up the WTU.Moreover this will reduce the operational costs by introducing a significant energy saving.