Study on operation characteristics of a compact megawatt nuclear power system

A novel compact megawatt nuclear power system with a heat pipe reactor coupled supercritical CO2 Brayton cycle has been proposed. To investigate its transient operational characteristics, this paper conducts open-loop dynamic response analyses and designs control systems for it under the load-following mode and the reactorfollowing mode. Subsequently, transient operational characteristics analysis of the system under different operating conditions is conducted. The results indicate that under load-following conditions, the rotation speed is highly sensitive to disturbances. The system can achieve a load variation of 0-100 % at a rate of 6 %FP/min, while at higher rates, there may be a decrease in speed due to exceeding the regulating range of the bypass valve. It can also accommodate continuous stepped load variations and operate at any desired load level. Under load rejection conditions, the system experiences significant fluctuations, but it can still maintain a new steady state and keep parameters within a safe range. In reactor-following mode, the system can achieve rapid power changes.