Fusion Science and Technology / Volume 54 / Number 2 / August 2008 / Pages 470-474
Technical Paper / Water Processing
These days more and more modern electrolysis cells are operated with new solid polymer membranes. These membranes prevailing DuPont's Nafion® are not only used for electrolysis but as well for the wide spectrum of fuel cells due to their good mechanical and chemical stability and the high proton conductivity. For that reason it is intended to use these solid polymer membranes for the electrolyzer units in the ITER Water Detritiation System (WDS). The influence of Tritium during water electrolysis to the membrane material is still not sufficiently investigated. Therefore long-term experiments of solid polymer membranes were performed at Tritium Laboratory Karlsruhe (TLK). The chemical degradation and durability behavior of the used Nafion® 117 membrane are investigated in details under tritiated water conditions. For comparison a second cell was operated with demineralized water for the same period.
In addition to the experimental rigs with single Nafion® membranes, two industrial electrolyzer units equipped with Nafion® membranes were operated during different tritium experiments at TLK. Before operation they had been modified to be compatible for tritium operation. After long operation period no degradation in the performance of the electrolyzers is observable.