Research on Fast Opening Setpoint of Turbine Bypass Discharge Valve in Nuclear Power Plant

When the difference between the average temperature of primary loop and its reference value exceeds the setpoint, the discharge valves of turbine bypass system (GCT) are fully opened quickly. So, it is suitable for the demand of steam discharge under large transient conditions. The main parameters and discharge valves configuration of GCT in HPR1000 Nuclear Power Plant are newly designed. If the setpoint designs of GCT are unreasonable, there will be a risk of reactor trip at large transient conditions. Therefore, it is necessary to study the fast opening setpoint of discharge valves. The system analysis code was used to analyze the influence of fast opening setpoint at above transients. The operation margins and the dynamic response process of the valves under different fast opening setpoint were obtained. The setpoint has been successfully applied to HPR1000 nuclear power plant demonstration project. This research method can be used to design the setpoint of GCT discharge valves of other reactor types.