Development of a web-based radiological emergency preparedness system for nuclear accidents

•A radiological emergency preparedness system has been developed to predict the behavior of radionuclides in the environment.•The system consists of atmospheric and marine dispersion, and dose assessment modelswith a graphic user interface module.•The developed system is an important tool for nuclear emergency preparedness in Korea.•The information obtained using the system will be used as a tool to enable rapid government response to a nuclear accident.