Plant-level dynamic modeling of a commercial-scale molten salt reactor system

Abstract

Ongoing research by the authors has led to a dynamic modeling approach that was verified against experimental data from the Molten-Salt Reactor Experiment (MSRE). These lumped-parameter models, characterizing the reactor dynamics, are nonlinear and represent changes in mass, energy, and temperature in all parts of the reactor plant. The reactivity feedback effects due to changes in temperature and Xe-135 concentration are taken into account. These models can be used to study both the time and frequency response to perturbations caused during normal operating conditions and during anomalies resulting from failure of certain sub-systems. A plant-level dynamic model of a representative molten salt reactor system developed based on the same methodology is presented here. A once-through steam generator providing superheated steam and reheated-regenerative Rankine cycle balance-of-plant system are coupled to the plant model. Results from simulation are presented for various transients and the resulting response of the plant is analyzed. Frequency response of the plant is also presented for various boundary conditions on the secondary side. Modeling results suggest that the inherent temperature-related feedbacks result in load-following characteristics that can be leveraged to engineer control systems offering a great deal of autonomy.