Abstract: An electrochemical hydrogen isotope concentrating apparatus is disclosed. The apparatus includes an inlet stream of the hydrogen isotope to be concentrated. The apparatus also includes an electrochemical cell that includes a hydron exchange membrane containing hydrons of the hydrogen isotope, an anode on a first side of the hydron exchange membrane in fluid communication with the inlet stream, a cathode on a second side of the hydron exchange membrane, and an electrical circuit connection between the anode and the cathode. The apparatus further includes two outlet streams: a first outlet stream of the hydrogen isotope in fluid communication with the cathode, and a second outlet stream depleted of the hydrogen isotope in fluid communication with the anode.