Investigations on ³He: Hydrogen Isotope Separation Employing Palladium/Silver Membranes

Abstract

Tritium resulting from separation processes is being stored in metal hydrides. In time, because of radioactive decay, tritium converts into ³He, which accumulates in the storage vessel. The recovery of ³He is a topic of high interest because of its wide range of applications in health care, security, and advanced research. Currently, at ICSI Râmnicu Vâlcea, a method is under development based on gas chromatography, Pd/Ag membrane permeation, and cryogenic distillation for ³He separation and enrichment having as sources both the cover gas of nuclear reactors and tritium storage containers. This paper reports the investigation of using Pd/Ag membranes for helium separation from hydrogen isotopes by experimental determination of the operating performance of the membrane in view of process integration. Tests have been performed at different temperatures in the domain of 100°C to 350°C for different hydrogen partial pressures in the upstream side of the membrane in the domain of 150 to 300 kPa, while the downstream part was continuously purged with a preliminary vacuum pump. The results for the membrane parameters are in good agreement with previous literature reports and will be utilized for the dimensioning and establishing of operating parameters of the membrane used for intermediate separation of helium isotopes from hydrogen.

Keywords:

• Helium-3
• membrane permeation
• helium isotope separation
• palladium/silver membrane

Acknowledgments

This work was carried out through the “Nucleu” Program, contract number 9N/2019, developed with the support of the Ministry of Research, Innovation and Digitalization, project number PN19110104, “Innovative CECE Process Solution for Promoting a New Decontamination Technology of Liquid Waste Poorly Concentrated in Tritium and for Recovery of Deuterium.”

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Romanian Ministry of Research, Innovation and Digitalisation [PN19110104].