Separation of hydrogen isotopes is required for the long-term success of fusion energy. Various systems are being used to accommodate this need including cryogenic distillation, electrolysis, pressure swing absorption, and others. Currently, the cost, complexity, and size of these systems is, however, not amenable to long-term economic success.The use of palladium/silver (PdAg) membranes is well-established for hydrogen gas separation systems. This system has also been examined for use in hydrogen isotope separation. Isotope selectivity is however limited by inversely competing mechanisms of solubility and diffusivity, i.e. heavier isotopes have lower diffusivities but higher solubilities. The use of a thinner membrane could reduce/eliminate the diffusion-limited behavior of the material and provide improved isotope separation. Also, a thinner membrane can improve overall isotope permeability, reduce processing temperature requirements, and reduce the precious metal content of the system.Skyhaven Systems proposes to develop a hydrogen isotope separation system based on a microchannel design. The design will allow for a higher surface area-to-volume ratio that will reduce the separator system size and allow for easy scale-up. In the Phase I effort, Skyhaven will fabricate the proposed microchannel design, test the design for hydrogen isotope separation and permeability as a function of temperature, pressure, and membrane thickness, demonstrate the fabrication of a multi-element separation unit, and develop a model to describe the separation process. The separation of hydrogen isotopes from one another is desirable for multiple industries including nuclear fusion reactors, medical imaging, and cancer therapy. Other potential uses for this separator include separating isotopes in rare isotope beams (linear accelerators) and would also provide potential cost savings to businesses currently involved in pure hydrogen gas separation.
