A reactor, system and method for producing hydrogen features a reactor containing a heating stream channel and a hydrogen channel with a reaction channel positioned there between. A heat transfer sheet separates the heating stream channel and the reaction channel and a porous support plate separates the reaction channel and the hydrogen channel. A membrane constructed from palladium, vanadium, copper or alloys thereof covers the porous support plate. The heating stream channel receives a heating stream so that heat is provided to the reaction channel through the heat transfer sheet. A catalyst is positioned in the reaction channel and the reaction channel receives a reaction stream including a mixture of supercritical water and a hydrocarbon fuel so that hydrogen is produced in the reaction channel and is passed through the membrane into the hydrogen channel. The hydrogen separation may alternatively be accomplished in a separator device distinct from the reactor via either a membrane or pressure swing adsorption.