NOVELTY - The hydrogen-producing fuel processing assembly (10) comprises a hydrogen-producing region (19) adapted to receive a feed stream (16) containing a carbon-containing feedstock, to produce a mixed gas stream containing hydrogen gas as a majority component and to operate within a hydrogen-producing pressure range, and a feedstock delivery system adapted to deliver a portion of the feed stream to the hydrogen-producing region. The feedstock delivery system is in communication with a liquid supply containing the carbon-containing feedstock, and includes a pump assembly (100).    USE - The assembly is useful for processing fuel to produce a product hydrogen stream that is useful as feed or fuel stream for a fuel cell stack.    ADVANTAGE - The fuel processing assembly is capable of efficiently and reliably producing the hydrogen gas with high performance.    DETAILED DESCRIPTION - The hydrogen-producing fuel processing assembly (10) comprises a hydrogen-producing region (19) adapted to receive a feed stream (16) containing a carbon-containing feedstock, to produce a mixed gas stream containing hydrogen gas as a majority component and to operate within a hydrogen-producing pressure range, and a feedstock delivery system adapted to deliver a portion of the feed stream to the hydrogen-producing region. The feedstock delivery system is in communication with a liquid supply containing the carbon-containing feedstock, and includes a pump assembly (100) adapted to draw a liquid inlet stream containing carbon-containing feedstock from the liquid supply and to emit a liquid outlet stream intermittently within or above the hydrogen-producing pressure range, an inlet conduit through which the liquid inlet stream is drawn to the pump assembly, an outlet conduit through which the liquid outlet stream is emitted from the pump assembly, a delivery conduit in fluid communication with the outlet conduit and the hydrogen-producing region and a stall prevention mechanism. The pump assembly has an inlet for receiving the liquid inlet stream and an outlet for emitting the liquid outlet stream. A delivery stream is delivered to the hydrogen-producing region through the delivery conduit. The stall prevention mechanism includes a check valve positioned between the outlet conduit and the hydrogen-producing region and adapted to isolate pressure in the outlet conduit from pressure in the hydrogen-producing region during periods in which the pump assembly is not emitting the liquid outlet stream within or above the hydrogen-producing pressure range, and a bleed conduit in fluid communication between the outlet conduit and one of the liquid supply, the inlet conduit, the pump assembly and a burner associated with the hydrogen-producing fuel processing assembly. A bleed stream (120) intermittently flows through the bleed conduit. The stall prevention mechanism is adapted to reduce pressure in the outlet conduit during the periods. The bleed conduit includes an orifice that is sized relative to the outlet conduit to reduce pressure in the outlet conduit during periods. The stall prevention mechanism further includes a restriction valve adapted to selectively permit and selectively restrict flow of the bleed stream through the bleed conduit. The restriction valve is a solenoid valve. The restriction valve is operatively linked to the pump assembly to permit flow of the bleed stream through the bleed conduit when pressure in the outlet conduit is less than the hydrogen-producing pressure range and when the pump assembly does not emit the liquid outlet stream within or above the hydrogen-producing pressure range, and is adapted to restrict flow of the bleed stream through the bleed conduit when pressure in the outlet conduit is within or above the hydrogen-producing pressure range and when the pump assembly emits the liquid outlet stream within or above the hydrogen-producing pressure range. The pump assembly includes a positive displacement pump that is adapted to receive the liquid inlet stream during a refill stroke and to emit the liquid outlet stream during a discharge stroke. The stall prevention mechanism is adapted to restrict flow of the bleed stream through the bleed conduit during the discharge stroke of the positive displacement pump. The restriction valve is operatively linked to the positive displacement pump to permit and to restrict flow of the bleed stream through the bleed conduit during the positive displacement pump's refill stroke. The positive displacement pump has an internal chamber. The bleed conduit is in fluid communication between the outlet conduit and the internal chamber, and is integral to the pump assembly. An INDEPENDENT CLAIM is included for a method for delivering feedstock within a hydrogen-producing pressure range to a hydrogen-producing region of a hydrogen-producing fuel processing assembly.    DESCRIPTION OF DRAWING(S) - The diagram shows a fuel processing assembly with a feedstock delivery system.    Fuel processing assembly (10)    Feed stream (16)    Hydrogen-producing region (19)    Pump assembly (100)    Bleed stream. (120)