电伴热法消除KLD10辐射监测取样管线冷凝水的产生

Method of electric heat tracing eliminating KLD10 radiation monitors sampling pipe condensation

田湾核电站辐射监测仪表在探测安全壳负压排气KLD10的放射性活度过程中,受取样管线前后端温差影响,取样管线内气体介质会发生冷凝现象,凝结水进入取样监测装置,造成仪表故障。通过对KLD10辐射监测仪表取样管线中存在冷凝水的原因分析、去除方案的论证,确定采用电伴热工艺方案。在总体设计思路、伴热线缆的选取、温度监测、PLC供电控制等方面对去除KLD10取样管线冷凝水的方案进行了阐述,并通过调试,解决了运行过程中出现的一些问题。通过对KLD10辐射监测取样管线加装电伴热系统后,不但消除了取样管线内气体介质被冷凝,而且避免了气溶胶的损失,有效保证了对安全壳负压排气的辐射监测取样及辐射监测仪表的正常运行,维护了辐射监测通道的完整性。

Tianwan nuclear power plant radiation monitor,which detects the volume activity of containment vacuum exhaust gas of KLD10 system,is influenced by temperature difference of sampling pipeline,the gaseous medium in the sampling pipeline will condense,the condensed water flowing into the monitor sampling facility will cause fault.Through analysis on condensation existing in the sampling pipeline of KLD10 radiation monitor and argument of the eliminate scenario,electric heat tracing process program is determined.Program on KLD10 sampling pipeline condensation is stated in the following aspects as general design,choice on electric heat tracing cables,temperature monitoring and PLC power supply control,through commissioning,some problems existed during operation are solved.After electric heat tracing system is added on KLD10 radiation monitor sampling pipeline,the phenomenon of condensation in the sampling pipeline is eliminated and avoided the loss of aerosol,effective monitoring on containment vacuum exhausted gas,ensuring normal operation of radiation monitor,and integrity of radiation monitor channel.