Research and development of OTEC, a renewable energy power generation facility using seawater heat, is underway worldwide, and the development of a demonstration plant has been promoted in Korea. However, for the commercialization of OTEC, alternative operating scenarios must be derived for various environmental changes. Therefore, preemptively identifying the risk factors of the system, analyzing the effects of the system, establishing control items, and verifying the results through simulation are necessary. This study proposes a method to minimize risk factors along with a risk analysis of the risk factors of MW-scale OTEC, such as refrigerant leakage and riser loss. The selected OTEC was designed for 1070 kW-class facilities, and 36.6% of the total power is consumed by seawater pumps and refrigerant pumps. The refrigerant was assumed to be leaked owing to the opening of the valve to the top of the refrigerant tank, and the performance change was confirmed by assuming that the refrigerant leaked at an average rate of approximately 21 kg/s. In addition, the riser loss assumed a rapidly changing deep water temperature, and the system was operated to stop when the deep water temperature increased up to 18°C.