Modeling Nuclear Containment Liner Steel Liner Corrosion

摘要

Corrosion of containment liners has been observed on the outside surface that is in contact with the concrete containment building. Corrosion initiated on the outer surface of the liner, or the surface that is in contact with the concrete containment building wall, has been associated with foreign material left embedded in the concrete. Macrocell-accelerated localized corrosion appears to be the corrosion mechanism for outer diameter corrosion (OD-corrosion) of steel containment liners. Once initiated, localized corrosion can continue to propagate over a period of many years because the thick sections of concrete have sufficient water content and the ionic conductivity necessary to support the electrochemical corrosion reactions. The model presented depicts the electrochemical current density (and therefore corrosion rate) estimated due to the steel liner and rebar interaction with the foreign material at the point the foreign material is in contact with the liner. The model can be used to determine the probability of containment liner failure due to corrosion for the possible situation of a foreign material at the liner/concrete interface creating the macrocell as discussed above.