A mathematical model for predicting the dynamic response of the H. B. Robinson pressurized water reactor plant was formulated and compared with results from measurements made during full-power operation of the plant. The model was based on the basic conservation laws for neutrons, mass, and energy; design data from the safety analysis report were used to evaluate the necessary coefficients. The model included representations for point kinetics, core heat transfer, piping, pressurizer, and the steam generator. The experiment involved perturbations in control rod position and main steam valve opening. Periodic binary input signals and step inputs were used. Theoretical and experimental frequency responses were obtained from the model and the test data. The comparison showed that the model was capable of good predictions for reactivity perturbations and fair predictions for steam valve perturbations. A method was also demonstrated for using the test data for at-power determination of the differential control rod worth.