Standby Service Water Basins – Protective Coating failure

Underwater Coating Application to repair coating defects on carbon steel pipe (Nuclear Power Project – applicable to any industry with coated carbon steel in immersion service)

Coated carbon steel pipe in two concrete emergency cooling water basins demonstrated extensive coating failure and corrosion (see Figure 2) leading to thru-wall pitting of the pipe.  Corrosion rates were extremely high due to water chemistry and microbiologically influenced corrosion (MIC).

Both small and large areas were coated with an underwater epoxy.  Thousands of areas totaling several hundred square feet have been touched up.  Underwater applied coatings have been in service for over 5 years and are performing well.  Field adhesion testing was used to verify that adhesion values are adequate.