NOVELTY - A fuel cell power plant comprises a programmable controller programmed to control a fuel gas supply device (5, 10) to stop supplying fuel gas to an anode; control the oxidant gas supply device to supply dry oxidant gas to a cathode; control the electrical load to consume power; control the fuel gas purge device (15, 23) to supply dry oxidant gas to the anode when the residual fuel gas amount in the anode has decreased to a predetermined amount; and control the fuel gas purge device to stop supplying the dry oxidant gas to the anode when the residual fuel gas in the anode has been replaced with dry oxidant gas.    USE - The fuel cell power plant is used for a vehicle.    ADVANTAGE - The controller replaces the residual fuel gas in the anode with dry oxidant gas, then maintains the fuel cell stack in a closed state, thus preventing local cell formation in the anode due to mixing of the residual fuel gas with oxidant gas, and hence preventing corrosion of a catalyst layer of the cathode in a short period.    DETAILED DESCRIPTION - A fuel cell power plant comprises:    (1) a fuel cell stack comprising an anode and a cathode, which generates power according to a reaction of a fuel gas supplied to the anode and an oxidant gas supplied to the cathode;    (2) a fuel gas supply device which supplies the fuel gas to the anode;    (3) an oxidant gas supply device which supplies a dry oxidant gas to the cathode;    (4) a fuel gas purge device which supplies a dry oxidant gas to the anode;    (5) an electrical load which can be connected to the fuel cell stack to consume power generated by the fuel cell stack; and    (6) a programmable controller programmed to control the fuel gas supply device to stop supplying the fuel gas to the anode in response to an operation stop command from outside; control the oxidant gas supply device to supply the dry oxidant gas to the cathode; control the electrical load to consume the power generated by the fuel cell stack; control the fuel gas purge device to supply the dry oxidant gas to the anode when a residual fuel gas amount in the anode has decreased to a predetermined amount; and control the fuel gas purge device to stop supplying the dry oxidant gas to the anode when the residual fuel gas in the anode has been replaced with the dry oxidant gas.    An INDEPENDENT CLAIM is also included for a control method of a fuel cell power plant.    DESCRIPTION OF DRAWING(S) - The figure is a schematic diagram of a fuel cell power plant.    Fuel gas supply device (5, 10)    Anode effluent discharge passage (11)    Cathode effluent discharge passage (14)    Anode effluent purge valve (20)    Cathode effluent purge valve (24)