Apparatus and method of producing heavy water involving catalytic-electrolytic exchange processes

A method of producing heavy water involving a composite catalytic-electrolytic deuterium exchange process comprising passing liquid water from feed or a previous enrichment stage through a catalytic deuterium exchange region containing a hydrogen gas/liquid water deuterium exchange catalyst and then through an electrolytic cell region, said cell including an anode and cathode connected to an electrical power supply and separated from each other by an electrolyte permeable diaphragm and an electrolyte, passing hydrogen gas in countercurrent relation to the liquid water through the catalytic deuterium exchange region to effect deuterium exchange between the gas and the liquid and then to the electrolytic cell where the hydrogen gas is at least partially consumed by the anode and hydrogen gas is evolved at the cathode, passing the hydrogen gas evolved at the cathode to the catalytic exchange region to pass therethrough, taking the water from the anode side of the electrolytic cell, said water being depleted in deuterium and passing to waste or back to a previous stage, and taking as output a portion of the water from the cathode side of the electrolytic cell, said water being enriched in deuterium and passing to further enrichment stages.