Proton exchange membrane electrolyzers (PEMEs) have potential interest for use for hydrogen isotope separation from water. In order for PEMEs to be fully utilized, more information is needed on the stability of Nafion when exposed to radiation. This work examines Nafion 117 under varying total dosage and dose rate and in water or air. Analytical tools, such as infrared spectroscopy, ion exchange capacity, dynamic mechanical analysis, and total inorganic carbon-total organic carbon (TIC-TOC) were used to characterize the exposed membranes. The water from saturated membranes was analyzed by fluoride and sulfate emissions and TIC-TOC, which provided important data on the stability of the membranes during radiation exposure.