Recent studies have shown that the most likely failure mechanism for a Hanford double-shell tank (DST) is some form of localized corrosion (pitting or stress corrosion cracking). No systems are in place at Hanford to facilitate the early detection of the onset of localized corrosion should it occur in a waste tank. Because of this, a program was started in 1995
to improve Hanford's corrosion monitoring strategy. A two-year laboratory study was started at Hanford in 1995 to provide a technical basis for using electrochemical noise (EN) based corrosion monitoring in Hartford nuclear waste tanks to detect the onset of any form of localized corrosion. Based on this study, a prototype system was constructed and deployed in
double-shell tank (DST) 241-AZ-101 in August, 1996. A first-generation full-scale system was designed and installed into 241-AN-107 in September 1997. A second-generation full-scale system was installed in 241-AN-102 in August 1998. A third-generation system was installed in 241-AN-105 in January 2000. The design of the 241-AN-105 system and the results of its first six months of operation are described in this report.
Keywords: electrochemical noise, EN, localized corrosion, pitting, SCC, stress corrosion cracking, corrosion monitoring