核电汽机甩负荷后除氧器的瞬态分析

Transient Operation Analysis of Deaerator in Load Rejection Condition of Nuclear Power Turbine

在核电机组设备中,无论是核岛设备,还是常规岛设备,最重要的是确保设备安全和稳定运行。设计核电系统时,还需要考虑特殊工况下的运行条件。当汽机甩负荷后,低压加热器、高压加热器及除氧器的加热汽源将全部失去。为防止蒸发器的换热管因温差过大而被破坏,除氧器的供水水温仍应保持一定的温度。在保压蒸汽通入除氧器之前,凝结水不会被低压加热器加热。在水温很低的条件下,仍需保证给水温度不低于蒸发器所要求的供水温度。而且,在反应堆降负荷的过程中,利用通入的保压蒸汽,还必须在低负荷工况下维持稳定运行。为此,对盘式除氧器是否仍满足运行条件进行了分析和论证,分析了甩负荷过程中除氧器的瞬态压力和瞬态温度。当机组在低负荷下稳定运行时,对整个运行参数进行了传热计算,验证了除氧器可以在该工况下稳定运行。在设计方案上,确保了整体热力系统运行的安全性。

It is necessary to consider the operating requirements under special operating conditions when designing a nuclear power system. All heaters lose their heating steam source in the nuclear power unit rejection load condition. In order to prevent the heat exchanger tube from being damaged due to the large temperature difference, maintain pressure steam shall be connected to the deaerator so as to raise the temperature of the feedwater. In the process of reducing the load on the reactor, the maintain pressure steam is used to maintain the operation of the deaerator under low-load condition. Therefore, the transient pressure and transient temperature of deaerator during load rejection have been analyzed, and the heat transfer has been calculated. The sate operation of the deaerator is ensured by the design scheme.