In this study, based on accident scenarios that can actually occur when hydrogen fuel is applied to power plants, the damage range of four risk factors(toxicity, flammability, overpressure due to explosion, and thermal radiant heat) was analyzed in case of a hydrogen leak accident. When setting up scenarios, the environmental and topographical characteristics of power plants located on the inland and coast were reflected. This is to confirm the effect of regional turbulence, wind speed, and surrounding obstacles on the damage diffusion modeling results(range). Combined cycle power plants in the inland and coastal areas of South Korea were selected as risk assessment targets and compared. Through the results of this study, it is expected to identify possible risk factors as applying hydrogen fuel in power plants and be used basic data for the design of customized hydrogen fuel supply, storage facilities and safety system.