Off-design performance and power-control strategy for combined cycle coupled with high-temperature gas-cooled reactor

Highlights: • A power-control strategy for the CC-HTGR was developed. • Control method called integral mass flow control. • The bottoming cycle runs is adjusted by sliding pressure. • The topping cycle is controlled by the inventory. • CC-HTGR can operate efficiently in the load range of 100% to 30%. - Abstract: High-Temperature Gas-cooled Reactors (HTGRs) have excellent development prospects because of their inherent safety and multiple application areas, such as hydrogen production. The combined cycle coupled with HTGR is a type of cycle for cascade utilization of energy that can efficiently convert heat from HTGR. In this paper, an off-design control strategy, called integral mass flow control, is proposed. The calculation model is discussed, and the performance at partial load is analyzed. When the load changes, the topping cycle is controlled by the inventory, and the bottoming cycle is adjusted by sliding pressure (the temperature of the main steam remains unchanged, and the pressure changes with the load), while the mass flow of the topping cycle and that of bottoming cycle changes synchronously. With this control strategy, the combined cycle coupled with the HTGR can be operated safely and efficiently within a load range of 100% to 30%.