Analytical transmission electron microscopy characterizations have been performed on intergranular stress-corrosion crack tips in cold-worked 316LSS after crack-growth tests in high-temperature water environments. Stable crack propagation rates were established in BWR oxidizing (2000 ppb O2) and BWR hydrogen water chemistry (74 or 1560 H2). Samples were then removed under load for cross-section, crack-tip preparation. General crack and crack-tip characteristics were similar in all cases with cracks narrowing to nm dimensions and thin, oriented, Cr-rich oxide wall films running into the leading grain boundary. However, subtle structure and composition differences in the tip oxides have been identified between cracks produced in oxidizing versus hydrogenated conditions. These variations are believed to result from chemistry and electrochemistry differences at the crack tip.
Revised: July 22, 2010 |
Published: August 23, 2007
Citation
Bruemmer S.M., and L.E. Thomas. 2007.COMPARISON OF IGSCC CRACK-TIP CHARACTERISTICS PRODUCED IN BWR OXIDIZING WATER AND BWR HYDROGEN WATER CHEMISTRY CONDITIONS. In 13th International Conference on Environmental Degradation of Materials in Nuclear Power Systems, 1711-1724. Toronto, :Canadian Nuclear Society. PNWD-SA-7882.