Dynamic simulation and optimization of load change operation of high-temperature gas-cooled reactor pebble-bed module

High-temperature gas-cooled reactor pebble-bed module (HTR-PM) is a new type of advanced nuclear power plant developed in China. In this paper, a dynamic process model is developed in hierarchical modules, with a thermodynamic model based on IAPWS-IF97 embedded for the calculation of the physical and transport properties. Based on the developed differential-algebraic equation (DAE) model, a dynamic optimization is conducted to minimize the transient operation time at load changes. Both the synchronous and the asynchronous module operation modes are tested. A comparison with previous rule-based operation results shows that dynamic optimization can achieve better performance in transient operation.