Investigation on efficiency of gas liquid contactor used as tritium extraction unit for HCLL-TBM Pb-16Li loop

Abstract

One of the main open issues in the design of the HCLL Test Blanket System for nuclear fusion energy applications is the design and testing of the Tritium Extraction Unit (TEU). The lead-lithium alloy which, in the HCLL blanket project, is used both as tritium breeder and neutron multiplier, will generate tritium that must be extracted with an efficiency as high as possible in order to keep low the tritium concentration in the liquid metal, then minimizing tritium permeation into the main coolant, the consequent CPS load and, last but not least, tritium permeation into the Port Cell through the PbLi loop pipes. Gas-liquid contactors (GLC) and, more in detail, packed columns are the reference technology for TEU of European ITER HCLL-TBS. An experimental campaign on a GCL packed column was performed in TRIEX (TRItium Extraction) facility in ENEA Brasimone Research Centre. Starting from the experimental results a parametric analysis was performed in order determine the basic parameters of the gas extraction process and consequently the efficiency of this technology in different operative conditions.Experiments were conducted at a constant temperature of 450°C varying the mass flow rate in the range 0,1–0,35kg/s for lead lithium and 5–150 Nl/h for Ar stripping gas. The hydrogen partial pressure in lead lithium at extractor inlet was investigated in the range between 8.000–14.300Pa.The experimental results have shown a tritium extraction efficiency in the range between 10 and 30% in good agreement with past experimental results obtained in MELODIE loop in CEA using similar packing material.