凝汽器在役铜管涡流探伤判废标准

Rejection Criterion of Operating Condenser Tube by Eddy Current Detection

在役凝汽器铜合金管经过涡流探伤后,有部份管子超标判废,并在探伤后进行闷堵,使凝汽器冷却面积减少,当闷堵量达到一定比例后,要进行整批调管。大型机组调换一次铜管要耗资数百万元,每延长一个大修期的管子使用时间,可节约数十万元材料费用。为了保证凝结水水质和延长铜管的使用期限,对铜管涡流探伤判废基准的合理性进行探索,为今后制定在役凝汽器铜合金管涡流探伤判废标准提供参考依据。

Eddy current flaw detection is a prevailing non-destructive/ntest for condenser tube leakage identification. The leaked tubes identi-/nfied by the detection should be temporarily plugged which would reduce/nthe condenser cooling surface. When the plugged tubes has reached a/ncertain proportion to the total amount of the tubes, an expensive retu-/nbing has to be taken place. As the eddy current detection is a indirect/nmeasurement which uses the eqivalent aperture as the standard for reje-/nction criterion, the establishment of an appropriate standard for the/nreplacement of the tube should be carefully studied in order to obtain a/ngood compromise between safety and economy.