FUEL PROCESSING APPARATUS FOR FUEL CELL, AND FUEL CELL SYSTEM

A fuel processing apparatus for a fuel cell according to an exemplary embodiment of the present invention includes a reforming reactor, a burner, a water gas reactor, and a valve. The reforming reactor produces reformed gas from a gas mixture of water and a raw material for power generation. The burner supplies heat to the reforming reactor. The water gas reactor includes a reactor main body which is supplied with the reformed gas from the reforming reactor and reduces concentration of carbon monoxide in the reformed gas, and a cooling flow path which is installed in the reactor main body. The valve controls a supply of a cooling medium to the cooling flow path while distinguishing a startup and a normal operation of the water gas reactor.