核电站复式低加性能降低原因分析及治理探讨  

Analysis and Treatment of Duplex Low-pressure Heater Reduced Performance in Nuclear Power Plants

作　　者：刘勇[1] 周帅 陈伟[1] 赵清森[1] LIU Yong;ZHOU Shuai;CHEN Wei(Suzhou Nuclear Power Institute Co.,Ltd.;Yangjiang Nuclear Power Plant Co.,Ltd.)

机构地区：[1]苏州热工研究院有限公司,江苏苏州215004 [2]阳江核电有限公司

出　　处：《电站系统工程》2025年第2期71-74,共4页Power System Engineering

摘　　要：某核电机组复式低压加热器第1级加热器疏水管水封在机组满功率运行期间会随着运行时间增加出现水封失效,换热性能降低,导致机组出力损失2~3 MW。对水封丢失及影响机组出力的原因进行研究分析,根本原因为1号低压加热器抽汽管线的布置方式导致复式低加管束只能采用上下布置形式,结构限制致使1号低压加热器排空气管线无法布置在管束中间区域,仅能布置在壳体两端。直接原因为现场排气管线直径较小,管线太长,流动阻力偏大。不凝结气体未能及时排出,导致管束换热能力下降,引起出口温度降低而影响机组效率。抽汽流量降低后,U型水封的水位不断降低,最终降低至0.8 m后无法维持而丢失。提出了两种提升排气能力改造方案,为提高核电站机组出力能力提供改造方向。During the full power operation of a CPR1000 nuclear power unit,the U type drain pipe of the first stage heater in the duplex low-pressure heater will fail as the operating time increases,resulting in a decrease in heat exchange performance and a loss of 2~3MW in unit output.The reasons for the loss of water seals and their impact on the unit output are researched.The root cause is that the layout of the extraction pipeline of the No.1 low-pressure heater resulted in the double low-pressure heater tube bundle being arranged only in an up-down arrangement,and the structural limitations made it impossible to place the exhaust air pipeline in the middle area of the tube bundles.The direct reason is that the diameter of the on-site exhaust pipeline is small,the pipeline is too long,then the flow resistance is too high.The un-condensable gas was not discharged quickly,causing a decrease in the outlet temperature and affecting the unit efficiency.After the extraction flow rate decreased,the water level of the U type water seal continued to decrease,and eventually dropped to 0.8m,which could not be maintained and was lost.Two renovation plans have been proposed to enhance the exhaust capacity,providing direction for improving the output capacity of nuclear power plant units.

关 键 词：复式低加 排空气管线 U型水封 换热能力 机组出力 

分 类 号：TK267[动力工程及工程热物理—动力机械及工程]