论文部分内容阅读
About a decade ago,it was discovered that chloride had a much larger effect on SCC of low alloy pressure vessel steels than sulfate.This talk summarizes recent findings on the effect of <5 ppb chloride on the stress corrosion cracking of pressure vessel steels in BWR water,and addresses the relevance in PWR primary water.There is a synergy among corrosion potential,stress intensity factor,chloride,yield strength and perhaps sulfur content of the steel that can cause elevated growth rates.With operating time,pressure vessel steels accumulate radiation damage,and in addition to the effect on fracture toughness,the radiation damage produces a significant enhancement in yield strength,which in turn has a large effect of SCC susceptibility.Despite the surprising finding that chloride had a potent effect,little evaluation of other impurities-such as nitrate,fluoride,phosphate,chromate,etc.-has been performed.