NOVELTY - The fuel reformer comprises a first burner (10) having a first end, a second end and a first opening in the first end, a second burner surrounding the first burner and having a first end, a second end and a second opening in the second-burner first end, a steam reforming reactor to be heated by heat generated from the first and second burners, and a fuel supply comprising a nozzle unit in the first burner for supplying a second oxidation fuel from an external source to the first burner. The second-burner second end is coupled to the first-burner second end to communicate a fluid.    USE - The fuel reformer is useful to produce hydrogen-rich gas, and in a fuel cell system to supply reformate to fuel cell stacks.    ADVANTAGE - The fuel reformer is capable of improving reformer endurance (prevention of deterioration), performance and efficiency by restricting a back pressure of a burner and complete oxidation (burning) in an environment-friendly manner.    DETAILED DESCRIPTION - The fuel reformer comprises a first burner (10) having a first end, a second end and a first opening in the first end, a second burner surrounding the first burner and having a first end, a second end and a second opening in the second-burner first end, a steam reforming reactor to be heated by heat generated from the first and second burners, and a fuel supply comprising a nozzle unit in the first burner for supplying a second oxidation fuel from an external source to the first burner. The second-burner second end is coupled to the first-burner second end to communicate a fluid. The fuel reformer is configured to receive a first oxidation fuel introduced into the first opening to flow through the first burner in a first direction and flow through the second burner in a third direction opposite to the first direction, and to discharge the second oxidation fuel from the nozzle unit in a second direction crossing the first direction. The fuel supply has a pipe shape with a closed end, and the nozzle unit is at the closed end. The nozzle unit comprises a pipe-shaped nozzle body having nozzle holes arranged in a radial direction of the pipe-shaped nozzle body, and is disposed to be spaced apart from an inner wall of the first burner or the first-burner second end. The nozzle holes are arranged in rows spaced apart from each other in the longitudinal direction of the pipe-shaped nozzle unit. The first burner comprises a first metal monolith having a cell density of 400-600 cell per square inch. An oxidation catalyst is coated on the first and second metal monoliths. The second burner comprises a second metal monolith having a cell density of 100-200 cell per square inch. The second metal monolith comprises chrome stainless, and first second and second second metal monoliths spaced apart from each other to form two rows. The first metal monolith is disposed closer to the first-burner second end than the first-burner first end. A fuel distributor is placed between the first opening and the first metal monolith, and is a circular plate having holes and configured to distribute the first oxidation fuel introduced into the first opening to surround the first metal monolith adjacent to an inner wall of the first burner. A flame preventing unit is provided between the fuel distributor and the first metal monolith, and has an identical cell density as that of the first metal monolith. The second oxidation fuel comprises an anode off gas discharged from a fuel cell stack. The anode off gas is supplied at a rate below 4 standard liters per minute. The steam reforming reactor is arranged for performing steam reform of a reforming fuel, and surrounds the first and second burners. A shift reactor is placed surrounding the first and second burners and the reforming reactor. The fuel reformer further comprises an ignition pipe having a first end coupled to the first burner second end, and an ignitor at a second end of the ignition pipe, where the second end is placed opposite to the first end.    DESCRIPTION OF DRAWING(S) - The figure shows a vertical sectional view of a fuel reformer.    First cylindrical partition (2)    Second partition (4)    Second end path (5)    Outer wall (6)    First burner. (10)