Memory Effects in Measurements of Low Tritium Concentrations as Required for the Outlet of the TEP System of the ITER Fuel Cycle

One of the tasks of the Tritium Laboratory Karlsruhe (TLK) is the development of a fuel clean-up system for future fusion reactors. The current reference process for the Tokamak Exhaust Process (TEP) system of ITER is called CAPER and consists of three different steps; the third step is based on counter current isotopic swamping to recover trace amounts of tritium in the so called PERMCAT. For testing the efficiency of the PERMCAT tritium concentrations below 3.7*10¹⁰ Bqm^-3 need to be measured in a process gas, challenging real time measurement, a wide measurement range of at least 4 orders of magnitude and low memory effects. The sampling technique used at TLK to measure the tritium concentration at the outlet of the PERMCAT is discussed in details with regards to memory effects.