A model-based methodology for developing a real-time expert system for process disturbance management has been presented in the companion paper. The application of the methodology to a target process - the main feedwater system of a pressurized water reactor (PWR) nuclear plant employing a complex control scheme - is presented in this paper. The performance test of the resulting real-time expert system, MOAS II, demonstrates that the expert system successfully fulfills its intended objectives, i.e., early detection of occurring disturbance, correct diagnosis of the disturbance cause, and presentation of optimal control advice to the operator. Therefore, the model-based technique lends itself to the development of a valuable operator aid for on-line process disturbance management.