New models of generating plant with the light water reactor (PWR and BWR) have been developed for simulating the plant dynamics under not only the small power system disturbances but also the large disturbances. The developed plant model enables precise and effective analysis of power system dynamics considering the nuclear plant response to power system faults by combining the plant model with the conventional power system dynamics simulation program. This paper first describes the modeling of the nuclear plant, and next outlines the application for power system dynamics simulation with nuclear plant.