Session: Corrosion and Material Protection in Nuclear Systems
Is Localized Corrosion a Necessary Precursor to Alkaline Nitrate SCC of Carbon Steels? (C2026-00432)
Monday, March 16, 2026
11:30 AM - 12:00 PM Central
Location: 371 DE
Earn .5 PDH
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Stress corrosion cracking (SCC) and localized corrosion are the two primary documented threats to the integrity of carbon steel radioactive waste storage tanks at the Hanford Site. Numerous studies on localized corrosion and SCC in alkaline nitrate-rich waste simulants have been completed. Anecdotal evidence, such as iron oxides at SCC initiation sides, has pointed to a possible link between the two mechanisms, but despite the large volume of published literature no experimental link between localized corrosion and SCC has been established. To address these issues, a series of electrochemical experiments were designed and conducted on carbon steels and high purity iron in simplified simulants and crevice forming conditions. Additional tests using slow strain rate specimens with crevice formers in the gage were conducted to evaluate the susceptibility to SCC in nitrate simulants. The results show that the breakdown potential is influenced by the scan rate, and the breakdown potential increases with the concentration of hydroxide. Crystallographic pitting, preferential dissolution of ferrite and grain boundary attack were observed in samples immersed in all simplified simulants. These findings may be relevant to establish a transition to SCC given the addition of stress to the system.
