PURPOSE:To be able to keep the inner surfaces of condenser tubes under the optimum condition from the standpoint of anticorrosion and heat transfer performance by installing a ferrous ion injection facility and/or operating a sponge ball cleaning facility corresponding to the flow time of seawater as cooling water and seawater quality. CONSTITUTION:At the inner surfaces of condenser tubes, specified anticorrosive films are formed by the flow of cooling water with injected ferrous ion and after a polarization resistance value is kept over 10OMEGAcm<2>, normal operation is carried out in detecting the polarization resistance and heat transfer characteristic of the tubes. At that time, when chloride is not implanted into cooling water, the resistance value should be kept over 5X10<3>OMEGAcm<2> and heat transfer characteristic should not be under a design value and when implanted, the resistance value should be kept over 2X10<4>OMEGAcn<2> and heat transfer characteristic not under the design value and further, when cooling water is polluted by containing sulphur ion, the resistance value over 5X10<3>OMEGAcm<2> and heat transfer value not under the value reduced by about 10% of the design value and under said conditions, the operation of ferrous ion implantation into cooling water and sponge ball cleaning operation for the inner surfaces of the condenser tubes are carried out.
