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U.S. Department of Energy
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Oxide-film compositions on alloy 600 tubes from steam generators: Palo Verde and Saint Laurent. Final report

Technical Report ·
OSTI ID:354914
Alloy 600 tubing from the second support plate intersection zone of Steam Generator 2 of the Saint Laurent B1 Nuclear Power Station was examined. Also examined was tubing from the Palo Verde Nuclear Station, which was from a free span crevice formed by deposits bridging bowed tubes. Corrosion products on the tubing with SCC were characterized to assess the possibility of using the composition of these films to determine the local environment in steam generator crevices. The Auger in-depth composition profiles of the corrosion product films on the fracture faces were in accordance with MULTEQ calculations and suggested that crevice chemistries were alkaline to highly alkaline. The presence of Cu, which was detected on tubes from both plants, could have raised the electrochemical potential above the corrosion potential, decreasing the resistance of the tubes to IGA/SCC. Sulfur in a ratio of sulfide/sulfate of 1/4 on the Palo Verde tubing could have contributed to SCC in these tubes.
Research Organization:
Electric Power Research Inst., Palo Alto, CA (United States); Rockwell International Science Center (United States)
Sponsoring Organization:
Electric Power Research Inst., Palo Alto, CA (United States)
OSTI ID:
354914
Report Number(s):
EPRI-TR--104066
Country of Publication:
United States
Language:
English