Electrochemical Conversion of Radioactive Gas Phase Species

Open Access
Author:
Zafred, Gianfranco Alexio
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 23, 2009
Committee Members:
  • Clinton Matthew Mench, Thesis Advisor
  • Matthew M Mench, Thesis Advisor
Keywords:
  • radioactive
  • Electrochemical
Abstract:
In this study, radioactive gas phase materials that are extremely expensive to dispose of using conventional means were converted into easily and inexpensively disposable substances using electrochemical methods. This research was motivated by the need to develop radioactive gas disposal methods that are more efficient and less expensive then conventional technologies. Tritium, and C-14 tagged carbon dioxide, carbon monoxide, and hydrocarbons were the gases studied. The two main components that were vital to this study were a polymer electrolyte fuel cell and a carbon dioxide absorption bubbler. The fuel cell directly converted tritium gas to tritiated water, and carbon monoxide and hydrocarbons to carbon dioxide, hydrogen, and water. The carbon dioxide bubbler absorbed the gas and converted it into CaCO3 precipitate in water. Various measures were used to gauge the performance and conversion of the radioactive gas including measurement of pH, current, and voltage recovery of the fuel cell. The research confirmed that the tritium gas performed nearly identical to conventional hydrogen in a fuel cell. The equivalent cost to dispose of the gases converted during this feasibility study would have been over a quarter of a million dollars through the conventional combustion-based methods. The overall design goal of this project was successful. A working system that safely and efficiently converted radioactive gas phase materials into benign liquid and solid forms was developed and validated on a variety of gases for a fraction of the cost of conventional disposal techniques.