Advancing electrochemical technology for tritium separation: an application for fission and fusion energy

Abstract

This comprehensive review delves into the critical domain of tritium enrichment and hydrogen production, essential for the advancement of nuclear fusion and sustainable energy systems. It highlights the significance of tritium in fusion reactors which rely on a closed D-T fuel cycle, and the environmental challenges posed by tritium from Nuclear Power Reactors. The manuscript meticulously explores diverse tritium separation methods with particular emphasis on electrochemical approaches, especially proton exchange membrane (PEM) electrolysis. It examines advanced materials such as Nafion-graphene membranes, palladium membrane, and proton-conducting ceramics–while Pt, Ir, Au and their oxide as anode and Pt-C and Pt as cathode–elucidating their impact on separation factor. The advantages of electrolysis, including its simplicity, scalability, and ability to produce high-purity hydrogen while leveraging the Kinetic Isotope Effect (KIE) for tritium separation, are discussed in contrast to traditional, energy-intensive techniques like cryogenic distillation. Furthermore, the review covers separation mechanisms involving quantum sieving, chemical affinity, and isotope fractionation (IF), as well as the properties and potential of various separation materials like zeolites, metal–organic frameworks, and 2D materials. Tritium storage aspects, electrode materials, and PEM design and stability considerations are also addressed. Future research directions focus on enhancing material durability, optimizing separation efficiency, and reducing costs to meet the demands of large-scale fusion applications. This will lead to sustainable fusion energy development. Future advancements can significantly lower tritium enrichment cost due to coupling electrolysis with fuel cell and modern materials for electrodes and membrane. These efforts will increase the separation factor, enrichment factor and lower the cost due to optimization of KIE, IF and improved faraday efficiency.