Abstract
In this research, a mathematical model for dynamic behavior of a small modular reactor core with natural circulation flow is presented by Simulink toolbox of Matlab software. First, point kinetic equation by considering one group delay neutron simulated in the Simulink environment to investigate the time dependent neutronics behavior that important parameters of this equation such as mean generation time, delay neutron, fuel and moderator reactivity coefficient are calculated using the MCNPX code. Mann's model with one-dimensional Dittus-Boelter heat transfer coefficient was also used to investigate the heat transfer process from fuel to coolant, and after completing the proposed model, the system's response to insert of a step reactivity was evaluated. The results of this research show that the proposed model has ability to predict the dynamic behavior of a small modular reactor core with natural circulation flow.