Preliminary results from a nonlinear dynamic model of the Molten Salt Demonstration Reactor (MSDR) plant are presented. This model is coupled to an integral economizer Once-Through Steam Generator (OTSG) model with variable boiling length to simulate operation at different power levels. The reactivity effect of Xe-135 is also integrated to investigate open-loop load-following operation. Simulation results show that the reactor model is stable for the investigated reactivity perturbations. A load-following excursion is simulated by varying the feedwater flow rate through the steam generator. Results show that the MSDR can follow load demand in a stable manner through temperature-based reactivity feedbacks alone without requiring operator input. Future work involves development of instrumentation systems and control strategies to achieve near autonomous plant operation.