大型核电机组冷却剂屏蔽主泵动态模型及响应特性研究

为了提高核安全性,新型压水堆核电机组冷却剂主泵采用无轴密封式屏蔽电动机泵,但其转动惯量明显小于常规轴密封泵,因此具有不同的动态响应特性。针对屏蔽主泵转动惯量较小、对电压、频率波动敏感等特性,考虑运行过程中的摩擦转矩,建立了屏蔽主泵动态模型,并将其接入核电机组系统仿真模型。比较验证了主泵动态模型的有效性,并仿真分析了主泵惰转特性和频率、电压扰动响应特性及其对堆芯功率的影响。结果表明,摩擦转矩对屏蔽主泵半流量惰转时间有较明显影响,建模时应予以考虑;频率扰动对主泵转速、流量的影响比电压扰动更明显,在运行中应提高厂用电供电质量。

Study on Dynamic Model and Response Characteristics of Coolant Shielded Main Pump for Large Nuclear Power Plant

In order to improve the nuclear safety,the shaftless canned motor is applied to the reactor coolant system of the new ressurized water reactor.Because of the difference between the general shaft sealing pump and the shaftless canned pump,the shaftless canned pump has a less rotary inertia with different dynamic response characters.The main pump is sensitive to voltage and frequency fluctuation and has a less rotational inertia.Based on these characteristics,a dynamic model with friction torque taken into account of the shielded main pump is established and it has been connected to the simulation model nuclear power unit system.The effectiveness of the main pump dynamic model and the frequency and voltage disturbance response characteristics of the main pump have been simulated and verified.Besides,the influence on the core power is analyzed.The results show that the friction torque has a significant effect on the half-flow idling time of the main pump,and these characteristics should be taken into account.The influence of the frequency disturbance on the main pump speed and flow is more obvious than the voltage disturbance.Power supply quality should be improved in operation.