The increasing global demand for energy, coupled with the need for sustainable and environmentally friendly solutions, has led to a renewed focus on Small Modular Reactors (SMRs). These innovative nuclear reactors offer enhanced flexibility, scalability, and safety features, making them an attractive alternative to traditional large-scale nuclear power plants. SMRs can be integrated into decentralized energy systems, providing a stable and reliable backbone for renewable energy sources. This study presents a comprehensive simulation of SMRs performance using MATLAB, analyzing their dynamic response to load changes in a power grid. The simulation utilizes a detailed reactor model that combines neutronics and thermohydraulic models, along with a steam generator and turbine governor model. A proportional-integral (PI) controller is implemented to regulate the reactor's output, with parameters optimized using the Particle Swarm Optimization (PSO) algorithm to ensure precise control under varying conditions. The results demonstrate the potential of SMRs to efficiently adapt to dynamic load scenarios, highlighting their role in supporting a cleaner and more sustainable energy future.