Abstract
Corrosion behaviour of carbon steel used as reinforcing steel for reactor containment buildings (RCBs) in nuclear power plants (NPPs) was investigated by galvanostatic polarization tests. To examine the effect of prepassivation on depassivation of carbon steel surface, samples were prepassivated by 2-day immersion in saturated Ca(OH)2 solution with NaCl (0.05 M or 0.1 M) or without NaCl. Also, some samples were tested without prepassivation. Prepassivated and unprepassivated samples were galvanostatically polarised in Ca(OH)2 solutions of pH 12 with 0.001 M, 0.003M, and 0.005 M NaCl. Without regard to the prepassivation conditions, all the samples tested in Ca(OH)2 solutions of pH 12 with 0.003 M and 0.005 M NaCl suffered from pitting within 1 hour. However, no pitting was observed on the samples tested in Ca(OH)2 solutions of pH 12 with 0.001M over 100 hours, indicating the chloride threshold concentration of the carbon steel should be 0.001 M and 0.003 M. Since the prepassivation was performed in saturated Ca(OH)2 solutions with high concentrations of NaCl, it was expected that would be incorporated into the surface film on the prepassivated samples. However, all the samples with and without prepassivation showed the same chloride threshold concentration. This implies that the chloride ions incorporated into surface films during the prepassivation do not affect the depassivation of the carbon steel in Ca(OH)2 solution.
| Original language | British English |
|---|---|
| Pages | 1622-1629 |
| Number of pages | 8 |
| State | Published - 2016 |
| Event | European Corrosion Congress, EUROCORR 2016 - Montpellier, France Duration: 11 Sep 2016 → 15 Sep 2016 |
Conference
| Conference | European Corrosion Congress, EUROCORR 2016 |
|---|---|
| Country/Territory | France |
| City | Montpellier |
| Period | 11/09/16 → 15/09/16 |
Keywords
- Carbon steel
- Depassivation of rebar
- Prepassivation
- Reactor containment buildings