The JAERI (Japan Atomic Energy Research Institute) Fuel Cleanup system (JFCU), which accepts simulated fusion reactor exhausts and produces pure hydrogen isotopes and tritium-free waste, was tested at the Tritium Systems Test Assembly (TSTA) with gram levels of tritium in 1991 under the US/Japan collaboration program on Fusion Technology. In 1991, the JFCU system integrity and safe operation with gram level tritium were demonstrated. Component performances with tritium were also measured and further subjects for R&D were uncovered. The resident tritium inventory of the JFCU was evaluated at about six grams during TSTA loop operation with a DT (1:1) mixture. After these tests, all tritium used in the experiments was recovered as hydrogen isotopes gases.