NOVELTY - A steam reforming reactor comprises at least one hydrogen-selective, hydrogen-permeable gas separation module comprising a porous substrate, an intermediate porous layer overlying the porous substrate and including a powder having a Tamman temperature higher than the Tamman temperature of the porous substrate, and a hydrogen-selective membrane overlying the intermediate porous layer.    USE - For a steam reforming process for producing high purity hydrogen used in fuel cells.    ADVANTAGE - The invention is durable for a high temperature operation by preventing intermetallic diffusion while being thin enough to provide high fluxes of hydrogen gas. It has more uniform heating and more control over temperatures at points to avoid hot spots. It has minimal production of NOx within the integrated reactor and demonstrates greater efficiency than any power generating system.    DETAILED DESCRIPTION - A steam reforming reactor comprises a reaction chamber comprising a catalyst bed (70) to produce reaction products comprising hydrogen gas from a hydrogen-producing feedstock; and at least one hydrogen-selective, hydrogen-permeable gas separation module to receive the reaction products from the catalyst bed and to separate the reaction products into product stream comprising hydrogen and a byproduct stream. The gas separation module comprises a porous substrate, an intermediate porous layer overlying the porous substrate and including a powder having a Tamman temperature higher than the Tamman temperature of the porous substrate, and a hydrogen-selective membrane overlying the intermediate porous layer. INDEPENDENT CLAIMS are also included for:    (A) a steam reforming process for the production of hydrogen, comprising reacting steam with a hydrogen-producing feedstock at 200-700degreesC and 0.1-20 MPa in a steam reforming reaction chamber containing a reforming catalyst to produce a mixture of hydrogen and carbon dioxide with a lesser amount of carbon monoxide; and separating hydrogen from the reaction chamber and from carbon dioxide and carbon monoxide with a hydrogen-selective, hydrogen-permeable gas separation module; and    (B) an integrated steam reforming reactor-hydrogen fuel cell comprising the inventive reactor where the product stream containing hydrogen is delivered from the reactor to an anode compartment of a hydrogen fuel cell and the byproduct stream from the reactor is delivered to a cathode compartment of the hydrogen fuel cell.    DESCRIPTION OF DRAWING(S) - The figure is a schematic diagram of the reactor.    Catalyst bed (70)    Tube (71, 72)    Inlet (85)    Outlet (86)