Mitigation effect of alkaline water chemistry upon intergranular stress corrosion cracking of sensitized 304 stainless steel

Citation
Y. Wada et al., Mitigation effect of alkaline water chemistry upon intergranular stress corrosion cracking of sensitized 304 stainless steel, J NUC SCI T, 38(8), 2001, pp. 621-632
Citations number
28
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Nuclear Emgineering
Journal title
JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY
ISSN journal
0022-3131 → ACNP
Volume
38
Issue
8
Year of publication
2001
Pages
621 - 632
Database
ISI
SICI code
0022-3131(200108)38:8<621:MEOAWC>2.0.ZU;2-6
Abstract
Alkaline water chemistry (AWC) has been studied as a new water chemistry co ntrol to mitigate intergranular stress corrosion cracking (IGSCC) of sensit ized type 304 stainless steel (SUS304). The AWC was found to be capable of reducing crack growth rates (CGRs) of the IGSCC. At first, the direct effec t of AWC upon IGSCC was studied experimentally. The 1/4T compact tension sp ecimen was used for measurement of CGRs of the SUS304 in high temperature a nd high purity water. Crack length was monitored by a reversing direct curr ent potential drop method. The CGR of SUS304 at 400ppb O-2 concentration wa s reduced ten-fold when solution pH was increased to 9. During this time, e lectrochemical corrosion potential (ECP) of the specimen did not change so much. Second, it was predicted by a radiolysis calculation that the AWC wou ld reduce H2O2 concentration under the hydrogen water chemistry (HWC). Sinc e the H2O2 concentration was more effectively suppressed by AWC, the requir ed hydrogen concentration in feedwater to lessen the ECP of the reactor com ponents was lower in AWC than at neutrality. Therefore, an indirect effect, that is moderation of the corrosive environment, could also be expected in addition to the direct moderation effect under HWC condition.