Comparison of Passive Feedback Control versus Idealized Control of Multi-Module HTGR SPR

Abstract

This report investigates the efficiency and performance of passive mass flow rate control in the operation of the Holos-Quad reactor. It discusses various active and passive control strategies, with a specific focus on the use of a movable vane for passive control of the mass flow rate, and introduces an adaptive Model Predictive Control (MPC) algorithm for active control of drum and mass flow rate. The effectiveness of the passive control method was assessed via a one-hour load follow scenario implemented with various control strategies. These included active drum control, active drum control with passive flow rate control, active flow rate control, and combined active drum and flow rate control. All strategies were successfully able to follow the scenario, regulated within constraints, and demonstrated minimum tracking error. The study found that active drum control offered a rapid and sensitive reactivity response, whereas mass flow rate control effectively minimized temperature change in materials. Among the tested control strategies, the active drum control combined with passive mass flow rate control proved most advantageous for reducing cost and minimizing temperature changes vital for reactor integrity maintenance. The report concludes by suggesting further research to incorporate more realistic constraints and control objective weights based on mechanical limits, safety limits, and costs. It also proposes enhancing the accuracy of primary and secondary system models of the reactor and expanding the cost function of the MPC for safer and more efficient operations.