The vibration of the secondary cooling system the Kartini reactor works to remove heat from the primary cooling system so that the heating element stays below the safety limit of the specified operating temperature. One component that is supported is a pump that is needed one of them by the vibration analysis method. By using vibration analysis, the type of cause of damage to the pump can be detected without dismantling the pump, so that it can provide predictability of maintenance time, scheduling repairs, picking up damaged equipment before hazardous needs. Vibration measurement with vibration meter (Lutron VB 8202) is carried out on the bearing housing of the secondary cooling pump motor housing in the direction: vertical, horizontal and axial. The value of the vibration compared with the vibration pump standard (ISO 10816-3). From the results of pump vibration measurements, there are several pump parts whose conditions are classified as vibrations that can cause damage to these components, namely the pump motor section. The average vibration on the pump motor is 5.74 mm / s greater than 4.5 mm/s that is classified as a vibration velocity value which can cause damage to other pump components. The results of the symptom analysis of variations in the vibration of abnormal values in the pump motor are caused by looseness of rotation and damage to roller bearings.