This paper presents the development of a flexible and user-friendly reactor core dynamic model of a CANadian Deuterium Uranium (CANDU) reactor for control system applications using the commercial simulation package MATLAB/SIMULINK. The reactor core is divided into 14 zones, and a set of coupled kinetics equations are developed to describe the dynamic behavior of the zones. The interaction between neighboring zones is characterized in terms of coupling coefficients, which basically describe the possibility of a neutron born in one zone causing a nuclear reaction in another zone. The model also includes the dynamics of the xenon and iodine. Nondimensionalized representations of the reactor dynamic model are derived in detail. It is demonstrated that vectorization of dynamic variables can significantly simplify the modeling and simulation process for a multizone reactor. Transient behavior of the reactor has been simulated using the developed model.