核电厂SLC两系CPU信号不一致问题技术研究

核电厂重要厂用水和循环水过滤重要冷源系统中的压力信号由安全逻辑处理机柜内的两系CPU进行采集。安全逻辑机柜两系CPU的信号采集与运算周期同为固定的100ms,但两系CPU其运行是独立且不同步的,且每个CPU在每个周期内采集信号的时间点是固定不变的。当水锤波效应引起的压力波动产生小于100ms的信号被一系CPU采集,会立即非预期启动安全级电机和泵等设备。当两系CPU间逻辑执行不一致状态持续达40 s还会发出两系CPU不一致故障报警。通过分析研究,在CPU信号采集前端增加0.5s上升沿延时模块。结果表明:该研究解决了由于水锤波效应引起的压力波动所造成的闪发信号导致安全逻辑处理机柜内两系CPU不一致报警以及频繁非预期启动安全级电机和泵等设备的问题。

Research on Inconsistency of CPU Signals Between Sub-Systems in SLC of Nuclear Power Plant

The pressure signals in the important plant water and circulating water filtering important cold source system of the nuclear power plant are collected by the two series CPUs in the safety logic processing cabinet.The signal acquisition and operation period of the two series CPUs in the safety logic cabinet is the same as a fixed 100 ms,but the operation of the two series CPUs is independent and out of syne,and the time point of the signal collected by each CPU in each cycle is fixed.When the pressure fluctuation caused by the water hammer wave effect is less than 100 ms,the signal is collected by the first series CPU,the safety grade motor and pump will be started unexpectedly.W hen the logic execution inconsistency between CPUs of the two systems lasts for 40 seconds,the two series CPUs inconsistency fault alarm will be issued.Through the analysis and research,the 0.5 second rising edge delay module is added to the front end of CPU signal acquisition.The results show that the flash signal caused by the pressure fluctuation originated from the water hammer wave effect leads to the inconsistent alarm of the two systems of CPUs in the cabinet.And the unexpected frequent start-up of the safety grade motor and pump can be avoided.