Failure Analysis of Anchor Bolt of Container in Nuclear Island

During checking the anchor bolt torque of the container in nuclear island of a nuclear power plant, a bolt had broken. The visual examination, chemical analysis, metallography, phase analysis, SEM and electrochemical tests were performed and analyzed, The results showed that acid-washing solution seeped into the anchor hole during the container tank pickling and passivating. The bolt was tapered off to some extent due to crevice corrosion and galvanic corrosion and ruptured ultimately during the torque check. Several measures for the corrosion control were proposed.