核反应堆保护系统停堆断路器异常动作分析研究

Research and Analysis on Unexpected Action of Reactor Protection System Trip Breaker

本文通过深入分析某核电厂反应堆保护系统停堆断路器异常动作原因,研究核安全级控制系统与非核安全级控制系统间通讯及扫描周期的差异性和反应堆保护系统仪表质量位设置的特殊性,明确保护系统仪表质量位的阈值设计应该结合安全功能需求、工况和仪表特性进行综合考虑的原则,同时给出修改主蒸汽流量计超量程下限质量位阈值和调整机组下行时蒸汽发生器液位控制值的优化措施,增加了技术上和操作上的防护屏障,可以有效避免此类问题再次发生。该研究对核电厂机组安全稳定运行具有实际应用价值,并对后续机组及同行电厂保护系统动作机理研究具有借鉴意义。

The function of reactor protection system is to protect the integrity of the three nuclear safety barriers,which is an important system guarantee the safe operation of the reactor. Through in-depth analysis of a nuclear power plant reactor protection system trip breaker unexpected action, the differences of scan cycle in the nuclear safety and non-safety control system and the particularity of the quality bit are studied. It is clear that the design requirement of quality bit threshold should be combined with the safety function requirements, conditions, and instrument properties. At the same time, the optimization measures of modifying the mass level threshold of the main steam flowmeter over the lower limit of the range and adjusting the control value of the steam generator liquid level when the unit goes down are given. The technical and operational protection barriers are added, which can effectively avoid the recurrence of such problems. This research is valuable in application of safe and stable operation of nuclear power plant, and provides some references for reactor protection system action mechanism research of peer power plant.