Abstract: Currently throughout the world, gas turbine (power generation system) is used for fulfilling energy needs. Beside its abundant usage, it has high risk due to its unexpected failure nature. Thus, to mitigate the risk of gas turbine unexpected failure, risk assessment is important to be carried out. In this study, risk assessment is used to estimate the probability and magnitude of risk due to the unexpected system failures by considering different repair assumptions for gas turbine system. In order to measure the risk for different repair assumptions, the probability of failure and consequences are required. The probability of failure estimated using parametric Recurrent Data Analysis (RDA) approach while the consequences of failure analyzed based on reported data. The results indicated that minimal repair assumption leads to minimum risk compared to perfect and imperfect repair assumptions. Based on the results, it is concluded that the maintenance team need to follow minimal repair in order to minimize the expected cost of failure.