Causes and Improvement Suggestions of Sacrificial Anode Shedding in a Nuclear Power Plant Circulating Water Pipe

Non-uniform dissolution and partial breakdown were found in aluminum sacrificial anodes in a nuclear power plant circulating water pipe in a short time. Through chemical composition analysis, electrochemical performance test, coating thickness analysis on the back of anode and the simulation of scour effect of seawater on sacrificial anodes with different installation methods, the reasons for sacrificial anode shedding were analyzed. The results showed that the low content of indium element resulted in non-uniform dissolution of sacrificial abodes. The large installation clearance between the back of sacrificial anode and protected pipe, insufficient coating thickness on the back of sacrificial anode and super-size casting shrinkage in sacrificial anode, reduced the binding force between anode body and anode iron core, and then caused sacrificial anode to fall off.