田湾核电站1、2号机组主给水泵暖泵系统改造

Main Feedwater Pump Warm Pump System Modification of Tianwan NPP Unit 1&2

田湾核电站1号、2号机组中原设计的主给水泵暖泵系统暖泵时间太长,不能满足运行要求。对原暖泵系统运行情况及主要存在的缺陷进行了分析,提出了两种拟采用的改造方案,并通过对这两种改造方案的可行性进行了对比分析,确定了通过改造主给水泵出口逆止阀旁路管线以达到暖泵的要求,并通过7次试验,确定了最终的改造方案——4级节流孔板分级降压。通过对改造管线及未改造管线运行一个大修周期后的各个部位壁厚减薄情况的对比分析,证明了该改造方案满足主给水泵的暖泵要求,并且有效降低了管道冲刷腐蚀速率。

As Tianwan Nuclear Power Plant Unit 12 were designed,the warm pump time of the original design main feedwater pump warm pump system is too long to meet the operation requirements.This paper analyzes the running situation and the main defects of original warm pump system,and puts forward two retrofit schemes.Based on the comparison and analysis of the feasibility of these two improved schemes,it is decided to meet the warm the pump requirement through reforming the main feed water pump outlet non-return valve bypass line.And through the seven tests,Level-4 throttling orifice grading decompression is determined as the final improved scheme.Finally by comparing and analyzing any part of the wall thinning of the transformation pipeline and unimproved pipeline after running an overhaul cycle,it is shown that the improved scheme can satisfy the demands of the main feed water pump warm pump and effectively reduce the piping erosion corrosion rate.