Fusion fuel purification during the Tritium Systems Test Assembly 3-week loop experiment

The Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory has conducted its longest continuous integrated loop operation to data. This provided an opportunity to test some hitherto unproven capabilities of the TSTA fuel cleanup system (FCU). The purpose of the FCU is to remove impurities from a stream of hydrogen isotopes (Q ₂) representative of torus exhaust gas. During this run, impurities loadings ranging from 60 to 179 sccm of 90% N₂ and 10% CH₄ were fed to the FCU. Each of the two FCU main flow molecular sieve beds (MSBs) were filled to breakthrough three times. The MSBs were regenerated during loop operations. The experiment yielded two principle findings. The first is that using the cryogenic molecular sieve is very robust method for removing impurities from fusion fuels. While loop flow rates, pressures, and impurities concentrations varied, the MSBs continued unaffected, completely removing impurities. The second is that the first step in the MSB regeneration process proved to be very effective