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1741746 
Journal Article 
Advanced TEM characterization of stress corrosion cracking of Alloy 600 in pressurized water reactor primary water environment 
Sennour, M; Laghoutaris, P; Guerre, C; Molins, R 
2009 
Yes 
Journal of Nuclear Materials
ISSN: 0022-3115 
393 
2 
254-266 
WOS:000270251400008 
Advanced transmission electron microscopy techniques were carried out in order to investigate stress corrosion cracking in Alloy 600 U-bend samples exposed in simulated PWR primary water at 330 degrees C. Using high-resolution imaging and fine-probe chemical analysis methods, ultrafine size oxides present inside cracks and intergranular attacks were nanoscale characterized. Results revealed predominance of Cr(2)O(3) oxide and Ni-rich metal zones at the majority of encountered crack tip areas and at leading edge of intergranular attacks. However, NiO-structure oxide was predominant far from crack tip zones and within cracks propagating along twin boundaries and inside grains. These observations permit to suggest a mechanism for intergranular stress corrosion cracking of Alloy 600 in PWR primary water. Indeed, the results suggest that stress corrosion cracking is depending on chromium oxide growth in the grain boundary. Oxide growth seems to be dependent on oxygen diffusion in porous oxide and chromium diffusion in strained alloy and in grain boundary beyond crack tip. Strain could promote transport kinetic and oxide formation by increasing defaults rate like dislocations. (C) 2009 Elsevier B.V. All rights reserved.