HANARO is exhausted into the atmosphere through a secondary cooling tower for maintaining the core temperature. In this study, performance characteristics were investigated after performing maintenance on major equipment in cooling tower. The blade angle was adjusted to 16 degrees and the filler was changed to remove the interference factor of air volume by the sludge. The survey method measured the vibration during operation of the motor and the reducer. After start-up, the distribution of heat was checked with thermo-graphic camera. As a result, the overall distribution of heat was shown in the third reducer. The measured results can be used for determining the wear and tear according to the start-up time. Therefore, the measured result can determine the wears and tears of the motor and reducer according to the operation time.