An affordable structural material that will not corrode in the presence of high-temperature, high-pH, hydrogenated water has not been discovered. Even the best corrosion-resistant alloys rust, the only thing that makes one more corrosion resistant than another is the rate at which the corrosion occurs. The process is the same for both iron- and nickel-based alloys in prototypical primary reactor coolant. When these alloys are exposed to primary reactor coolant at high temperature under prototypic coolant chemistries, oxygen will diffuse into the base metal at the wetted surface and convert the elements in the alloy from the metallic state to an oxide state. Oxidation of these alloys is generally found to be congruent or nonselective (i.e., the elements oxidize in proportion to their weight percentages within the alloy), and the initial form and structure of the metal oxides is the same for both iron- and nickel-based alloys.

Even the best corrosion-resistant alloys rust, the only difference being the rate at which the corrosion occurs.

The Corrosion Source

Key Takeaway: Even the best corrosion-resistant alloys rust, the only difference being the rate at which the corrosion occurs.