This article characterizes vibration signals using Artificial Neural Network (ANN) method to develop an effective and reliable feature sets for detecting and diagnosing faults in a centrifugal pump (ETRR-2 research reactor core coolant pumps). In this paper, a modular ANN are used for modeling the ETRR-2 research reactor core coolant pumps vibration monitoring. The input and the output signals of the vibration transducer are used as input source data for the ANN model. The amplitudes and frequency domain are inputted to the ANN separately from the vibration data. It is noted that the features statistical have good results based on frequency and amplitudes domains. The ANNs are used to detect the misalignment, unbalance severity, looseness bearing, and anti-fraction. The results are very useful for maintenance making decision. This methodology can be used for the research reactor coolant pumps. Hence, it may turn out to be a powerful tool for early detection of pump fault.