Microstructural and Microchemical Characterization of Primary-Side Cracks in an Alloy 600 Nozzle Head Penetration and its Alloy 182 J-Weld from the Davis-Besse Reactor Vessel
Cracks in Alloy 600 and Alloy 182 upper-head-penetration welded components from the Davis-Besse pressurized-water reactor were characterized by high-resolution analytical transmission electron microscopy. Axial cracks in the Alloy 600 nozzle and both axial and circumferential cracks in the weld metal were examined at scales ranging from mm to less than 1 nm. Despite different metallurgical structures in the wrought nozzle and weld alloys, the observations in both materials revealed characteristic penetrative intergranular attack and corrosion products indicating that the degradation occurred by intergranular stress corrosion cracking (IGSCC) during service. Sulfur impurities and sulfide particles found near crack tips in the Alloy 600 nozzle also indicated that the IGSCC in this material was assisted by impurities from the primary-water environment.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 948776
- Report Number(s):
- PNNL-SA-45694; AF3510000; TRN: US0901708
- Resource Relation:
- Conference: 12th International Conference on Environmental Degradation in Materials in Nuclear Systems - Water Reactors, 567-578
- Country of Publication:
- United States
- Language:
- English
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