A 2:1 mixture of LiF and BeF{sub 2} (FLIBE), is a potential tritium breeder material for fusion reactors, in particular, the Advanced Safe Pool Immersed Reactor (ASPIRE). A limited experimental campaign was conducted in an effort to test the postulates of the ASPIRE concept: namely, that MoF{sub 6} is effective in controlling the tritium species by maintaining the FT form and that MoF{sub 6} can serve as a source to plate out Mo on surfaces, thereby making the FLIBE system compatible with the corrosive FT. It was demonstrated experimentally that successive additions of MoF{sub 6} achieved quantitative (i.e., greater than 99.7%) conversion of H{sub 2} to HF. Thus, MoF{sub 6} is effective in controlling the tritium species. The degree of conversion of H{sub 2} to H demonstrates that H does not attack MO to form H{sub 2}. This supports the postulate that the system is compatible with Mo. Thus, if it were possible to plate out and maintain a coating of Mo on all surfaces in contact with the FLIBE system, the ASPIRE concept could work. Thermodynamic calculations also confirmed that MoF{sub 6} should be capable of quantitatively (>99.9%) converting H{sub 2} to HF. There is both experimental and theoretical more » evidence that a number of MoF{sub x} species are present in both the gas phase and the FLIBE solution. 17 refs., 3 figs., 3 tabs. « less