Abstract: A reaction hydrogen production control mechanism is provided that includes, a solid sodium borohydride mixture, a liquid fuel reactant, at least one liquid delivery medium (LDM), a movable boundary interface (MBI) and a reaction zone, where the MBI is disposed to provide a constant contact between a reacting surface of the solid fuel mixture and the primary LDM to form the reaction zone. A reaction in the reaction zone includes a hydrolysis reaction. The MBI moves according to a spring, gas pressure, or an elastic membrane. Product paths are disposed to transfer reactants from the system. The product paths can include a channel on a surface of the solid fuel mixture, a channel disposed through the solid fuel mixture, a channel disposed about the solid fuel mixture, a contained region disposed about the solid fuel mixture, or a conduit abutting the solid fuel mixture.

Abstract: A hydrogen generator that includes a solid fuel mixture, a liquid reactant, a liquid delivery medium (LDM), a movable boundary interface (MBI), a reaction zone, wherein the MBI provides constant contact between a reacting surface of the solid fuel mixture and the liquid reactant delivered by the LDM to form the reaction zone, and a product separation media, fluidly coupled to the reaction zone by a fluid junction, that degasses a product. The hydrogen generator may further include auxiliary LDMs disposed throughout the hydrogen generator, wherein said auxiliary LDMs may be operated based on a ratio of the liquid reactant flow rate to the hydrogen generation rate.