Inventory Control Strategy and Transient Control Characteristics of 5 Mw Small Modular Supercritical Co2 Brayton-Cycle Reactor System

Abstract

Based on the previously developed 5 MW small modular SCO 2 Brayton cycle reactor system analysis program, a series of model improvements and algorithm optimization were carried out, and the dynamic model of the inventory control system was built. Firstly, the mechanism of the inventory control method is discussed and the transient operating characteristics of system load following under inventory control strategy are analyzed. Finally, the system startup and shutdown control strategy are established. The results show that the volume and initial pressure of the SCO 2 storage tank determine the power regulation range of the inventory control system. The inventory control method and sliding pressure operation can realize load following within the range of 66.7% to 114.1% of the system rated output power. Compared with the bypass control method, inventory control avoids reactor power fluctuation and rotor speed rise and has an absolute advantage in maintaining cycle efficiency. The stepped startup strategy can ensure that the system reaches the rated power within 90 min. A reasonable startup and shutdown control strategy can ensure that the main parameters of the reactor do not exceed the nuclear safety limit and that the compressor operation curve is within the surge margin.

Keywords: The small nuclear reactor system (SMR), Supercritical CO2 Brayton cycle, Transient operation characteristics, Inventory control, Cycle startup and shutdown