Decontamination of Proton Exchange Membranes After Tritium Exposure

Abstract

Canadian Nuclear Laboratories (CNL) is developing a Proton Exchange Membrane-based (PEM) electrolyser intended for tritium removal. Commercially available Nafion^® N-1110 membranes have been exposed to tritiated water (with a β activity of about 37 GBq/mL) prepared in the Tritium Facility at CNL. Three equivalent batches of Nafion^® N-1110 membranes (each with a dimension of 4 cm × 4 cm) were exposed to β-doses of 67 kGy, 155 kGy, and 255 kGy, respectively.

The exposed membranes required decontamination for characterization and testing. A few different decontamination methods have been experimentally studied. These methods can be categorized as water elution and chemical soaking. The measured tritium concentration in eluent decreased quickly in the first 30 days of water elution, followed by a slow decay afterwards until reaching a plateau after about 100 days. Chemical soaking proved to be more effective than the water elution method and high temperature facilitated the tritium release.

Keywords:

• Tritium
• proton exchange membrane
• decontamination
• β-radiation