Coordinated control system design of HTR-PM plant

The modular high temperature reactor (MHTGR), which adopts helium as coolant and graphite as moderator and structural material, has inherent nuclear safety. Based upon multi-modular scheme, i.e. the outlet steam flows of multiple nuclear steam supply system (NSSS) modules are combined together to drive a single turbine, the inherent safety feature can be applicable to the plants at any desired power ratings. However, the power control method of classical single-modular nuclear power plants (NPPs) cannot be applied directly. The coordinated control system design of HTR-PM plant, which is the first multi-modular nuclear plant being constructed in the world, is proposed in this paper. Then, the control system design is verified based on the full-scale simulator of HTR-PM plant, and the simulation results in the cases of power ramp down and high pressure heater bypass are given, which show the feasibility of control system design and the acceptable transient performance of the closed-loop.