This invention relates to an automation system for nuclear power plants. This system comprises operation plan making means, supervisory control means, and control means for controlling controlled objects. The operation plan making means makes a new operation plan to restore a normal operating condition which existed before the plant condition deviated from the normal operation range. The supervisory control means outputs control commands according to an operation plan under abnormal condition when the plant operating condition deviates from the normal operation range. Furthermore, the supervisory control means outputs control commands according a new operation plan prepared by the operation plan making means after an operation according to an operation plan under abnormal condition has been finished. The control means for controlling controlled objects controls the controlled objects according to control commands output from the supervisory control means.