蒸汽发生器排污能力不足问题原因分析和处理

Cause Analysis and Treatment for Insufficient Blowdown of Steam Generator

田湾4号机组蒸汽发生器排污系统在进行排污时,其排污能力长期不能达到运行规程要求,且此时系统调节阀开度已超过90%,丧失了调节能力。另外由于原系统设备经过改造,相关参数特性发生改变,所以通过仿真建模计算分析原有管路阻力特性的方法无法进行。本文选择利用核电厂现有运行参数,直接计算整个管路的装置特性曲线,分析得出原因为泵能力不足,然后按照规程要求的系统流量,考虑调节阀开度问题,计算得出泵的最终扬程,完成新泵的选型,最终有效地解决了排污能力不足的问题,为后续核电厂改造中解决类似问题提供了参考依据。

During the discharge of the steam generator blowdown system of Tianwan Unit 4,the capacity cannot meet the requirement of operation regulation,and the control valve opening had exceeded 90%,which leads to the loss of control capacity.Due to the modification of the original system equipment,the relevant resistance characteristics have changed.Therefore,the method of simulating and modeling to analyze the resistance characteristics of the original pipeline cannot be carried out.Herein,we chooses to use the existed operation parameters to calculate the device characteristic curve of the whole pipeline,and analyzes the reason which is the insufficient pump capacity.Based on the required flowrate by the regulation,the pump head was calculated to complete the selection of the new pump,which has been considering the factor of control valve opening.Finally,the problem of insufficient blowdown capacity is effectively solved,which provides a reference basis for solving similar problems in subsequent power plant renovations.