NOVELTY - A reforming fuel cell system is controlled by generating hydrogen-containing reformate, passing reformate through first reactor, reacting reformate with oxygen, inputting anode effluent into combustor, adjustably inputting oxidant into combustor, and transferring heat from exhaust stream to first reactor.    USE - Used in controlling of reforming fuel cell system.    ADVANTAGE - The invention is capable of heating fuel processor (10) components quickly to achieve high operating temperatures for start-up. It maximizes heat input into the fuel processor while minimizing tendency to form carbon. It minimizes use of electrical energy during start-up and the reliance on catalytic reactions.    DETAILED DESCRIPTION - The controlling of reforming fuel cell system involves generating hydrogen-containing reformate in a reformer (14), the reformate having level of carbon monoxide; passing the reformate through first reactor to reduce the level of carbon monoxide; reacting the reformate with oxygen in a fuel cell stack (22) to create electrical energy and an anode effluent; inputting the anode effluent into combustor to generate exhaust stream; adjustably inputting oxidant into the combustor to control temperature of the exhaust stream; and transferring heat from the exhaust stream to the first reactor such that the temperature of the first reactor is maintained within an operating range.    An INDEPENDENT CLAIM is also included for a method of rapidly starting fuel processing system comprising generating heated gas stream in heating device; directing heated gas stream through first side of heat exchanger; directing water through second side of heat exchanger (16) to produce steam stream; heating the first reactor with the steam stream at first rate of heating; heating second reactor with steam stream at second rate of heating; and controlling the heating device to adjust the heated gas stream to control the first and second rates of heating.    DESCRIPTION OF DRAWING(S) - The figure is a schematic view illustrating the fuel processor.    Fuel processor (10)    First burner system (12)    Reformer (14)    Heat exchanger (16)    Reactor (20)    Fuel cell stack (22)    Second burner system (24)