LOCA后物理现象对压力容器水位测量影响分析

Analysis of Impact on Vessel Water Level Measurement due to Post-LOCA Physical Phenomenon

为了验证CPR1000核电站冷却剂失流事故(LOCA)下堆芯冷却监测系统(CCMS)压力容器水位(L VSL)测量的有效性,对LOCA后影响动压和静压测量的物理现象,以及顶盖的特殊现象对L VSL测量引入的误差进行了量化计算。结果表明,顶盖的特殊现象和冷管段或热管段破口流量对L VSL测量引入的误差在破口发生几分钟后可忽略,压力容器顶部破口流量以及控制棒导向管内水的滞留对L VSL测量引入很大的高估误差,结合状态导向事故处理程序SOP的分析表明,该高估误差不会阻碍事故处理安全重要操作的执行。

To assess the validity of the L VSL（vessel water level）measurement of the CCMS（core cooling and monitoring system）in CPR1000 nuclear power plants under condition of LOCA（loss of coolant accident）,the error of the L VSL measurement due to the post-LOCA physical phenomenon which may have impact on the measurement of dynamic and static pressures,and the special phenomenon in vessel-head was quantitatively calculated.The analysis results show that several minutes after discharging through the break,the error of the L VSL measurement induced by the special phenomenon in vessel-head and cold-leg or hot-leg break flow rate can be ignored.The flow rate of the break on the vessel-head and the stagnant water in the control rod guide tube will induce a significant over-estimated error to the L VSL measurement.The analysis combined with SOP（state oriented procedure）shows that the over-estimated error will not hinder the implementation of the safety important actions for accident management.