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http://dx.doi.org/10.5855/ENERGY.2014.23.2.149

A Study on the Resistance of Stress Corrosion Cracking due to Expansion Methods for Steam Generator Tubes in Nuclear Power Plants  

Kim, Young Kyu (Hongik University)
Song, Myung Ho (Korea Institute of Nuclear Safety)
Publication Information
Journal of Energy Engineering / v.23, no.2, 2014 , pp. 149-157 More about this Journal
Abstract
The steam generator tubes of nuclear power plants have various types of corrosion failures during the plant operation. The stress corrosion cracking which occurs on the outer surface of tube is called the secondary side stress corrosion cracking and mainly occurs in the expansion-transition area of tube. The causes are the concentration of impurities by the sludge pile-up related to the geometry of its region and the residual stress by tube expansion in the process of steam generator manufacturing. Especially the directionality and sizes of residual stresses are differed according to the tube expansion methods and the direction and the frequency of tube cracks depend on their characteristics. In bases on the plant experiences, it is notified that circumferential cracks of tubes expanded with explosive expansion method are dominantly occurred compared to those of tubes done with hydraulic expansion one. Therefore in this study, according to tube expansion methods frequencies and sizes of tube cracks with specific direction are compared by means of accelerated immersion test and also the crack morphology and the specific chemicals from water-chemistry environment are observed through the fracture surface examination.
Keywords
Steam Generator Tube; Intergranular Stress Corrosion Cracking; Explosive Expansion; Hydraulic Expansion; Expansion Transition Area; Residual Stress;
Citations & Related Records
Times Cited By KSCI : 3  (Citation Analysis)
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