Hydrogen embrittlement due to mild condensate contamination by sea water ingress through condenser tube leakages: A case study

This paper presents an investigation on failed SA210-A1 rear riser water wall tubes through visual inspections, chemical analysis, video boroscope inspections, and microscopic examinations. Close inspections on the failed tubes revealed hard and thick dark brown scales deposited on the internal surfaces. Chemical constituents of the scales were confirmed to have magnetite from corrosion product. Cost saving observations by video boroscopes showed a severe degree of corrosion attacks on the internal tube surfaces. Microscopic examinations revealed significant evidence of decarburization with presence of macro- and micro-cracks. Hydrogen damage in the localized low-pH condition that caused the embrittlement of the material was evidenced by the findings of the investigation, and the root cause of the problem was believed to be due to mild sea water impurities through condenser tube leakages.

Research Highlights
► Cost saving observations by video boroscope showed a severe degree of corrosion attacks.
► Contamination by sea water ingress was the main root cause of the failure.
► Materials embrittlement was caused the localized low pH hydrogen attacks.
► Losing controls of plant water chemistry causing the problem are presented.