During the time period from 4/19 -5/5/89, the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory (IANL) conducted its longest continuous integrated loop operation to date. This provided an opportunity to test some hitherto unproven capabilities of the TSTA Fuel Cleanup System (FCU). Previous FCU tests were reported in [l]. The purpose of the FCU is to remove impurities from a stream of hydrogen isotopes (42) representative of torus exhaust gas. During this run impurities loadings ranging from 60 to 179 sccm of 90% Np and 10% CH4 were fed to the FCU. Each of the two FCU main flow molecular sieve beds (MSB's) were filled to breakthrough three times. The MSB's were regenerated during loop operations. PESCRIPTION 0 F THE T STA FCU Purification The FCU, shown schematically in Figure 1, employs 77 K MSB's (Linde 5A) to remove impurities from 92. MSBl and MSB2 are used to purify the main flow path (nominally 50/50 D/T), while MSB3 and MSB4 purify the neutral beam gas (nominally 100% Dg). During this run impurities were only added to the main flow path.Before the impurities break through on one bed, its exhaust is routed to the inlet of the companion bed (path not shown). In this way an MSB can be taken to 100% loading, leaving an insignificant amount of co-adsorbed Q2 when an KSB is regenerated.

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