Today, after more than twenty years of operation, the Egypt second research reactor (ETRR2's) electrical power system needs to be re-evaluated in order to be sure that the system is still adequate for present situation of continuous operation under different circumstances, which may be severe in someinstances. In the process of revaluation of the ETRR2's electrical power system, it is important to calculate the short circuit currents at several locationsin the system. For any electrical system, it is well known that determination of the short circuit current at different locations of the system is very important for two main reasons: first, selection of the short circuit rating for each equipment or switchboard and second, selection of the rating and setting for protective devices in the protection scheme. This work presents an analytical short circuit study of the ETRR2's electrical power system by building its model using Electrical Transient and Analysis Program (ETAP software), which was not available during the ETRR2 design stage at the time. The built model was validated by comparing its simulation results with the designer calculation that was performed on limited points of the system. The authors take the advantages of this new advanced software to evaluate the system in every point we need in the system. Depending on the results of this study, it is feasible to decide which protective device or equipment that needs upgrading to be adequately rated for present operating circumstances. Also, the verified model can be used in future expansion,