J. R. Wermer, D. G. Tuggle, E. N. Schmierer, D. A. Lohmeier, and M. C. Whitcomb
Engineering Sciences and Applications Division, Tritium Science and Engineering Group, Los Alamos National Laboratory, Los Alamos, NM 87545 USA)
A metal hydride-based tritium clean-up system has been successfully operated for more than two years on a helium glovebox which was used for handling metal tritide powders. Residues of the metal tritides serve as a source of high atmospheric tritium activity levels in the glovebox--the metal tritide reacts readily with oxygen and moisture impurities in the glovebox atmosphere to release HT or T2 gas. During the operational period, the clean-up system has removed several thousand curies of tritium gas from the glovebox while maintaining very low levels of oxygen and moisture. The system maintained a tritium activity in the glovebox of 300-500 mCi/m3. The clean-up system consists of two beds: 1) a ZrMnFe (in a 10% by weight Al binder, SAES ST909) bed operating at 600-700 C followed by 2) a Zr2Fe (SAES ST198) bed operating at 250 C. The ST909 serves to condition the gas stream by cracking hydrogenous impurities (such as H20 and hydrocarbons) and absorbing oxygen and carbon. The ST198 bed absorbs the hydrogen isotopes from the flowing stream.
Data on the performance of this system will be presented including the tritium removal rate during normal operation and the effect of various parameters (bed temperature, flow rate, and impurity levels, etc.) on the performance. Data will also be reported on the recovery of hydrogen isotopes from the ST198 bed. The behavior of the system during experiments employing very high moisture levels (introduced intentionally for glovebox decontamination) will also be reported.