[en] The first loop operation tests of Tritium Systems Test Assembly with 100 grams-level of tritium had been completed at Los Alamos National Laboratory in July, 1987. This test was the resumption of the previous milestone run halted on 26 June due to a mechanical failure of the refrigerator for the hydrogen isotope separation system. The objectives were (i) to operate the TSTA process loop for a week to demonstrate its major process systems such as the fuel cleanup system and the hydrogen isotope separation system, (ii) to demonstrate the safety systems such as the secondary containment system, tritium waste treatment system and tritium monitoring system, and to obtain handling experience with a large amount of tritium. This report describes characteristics of the safety systems observed during the milestone run. (author)