Abstract: Based on the theory of hardware-in-the-loop simulation, the functions of the compact integral effects test facility at the University of California, Berkeley, and integral effects test simulating the integral thermal-hydraulic response of fluoride-salt-cooled high-temperature reactors (FHRs) under forced and natural circulation operation, were improved to better reflect the characteristics of this kind of reactor’s operation. Modifications made on the facility’s control system including a neutron kinetics model, a reactivity feedback model, and temperature control and power control models were the foundational work necessary to make the facility simulate the behavior of an FHR. Results from temperature control experiments indicate that the facility’s heater can respond rapidly to the controller’s output and achieve the target temperature, similar to prototypical fuel temperature behavior. Better power control parameters and control results were then obtained by optimizing PID parameters of the point-reactor-based power control model, laying the foundation for the subsequent optimization of control logic and the study of the impact of parameter uncertainties.