Embrittlement of Alloy 400 by lead in secondary side steam generator environments
- Chalk River Labs., Ontario (Canada)
An investigation of intergranular attack and cracking of Alloy 400 steam generator tubes from an Ontario Hydro nuclear power plant identified lead as a possible embrittling agent. The aim of the present work was to establish whether Alloy 400 is susceptible to solid metal embrittlement (SME) or any other cracking mechanism by lead. A program of constant extension rate tensile (CERT) tests on Alloy 400 was performed, concentrating on the role of lead oxide in secondary side water. These show that a high level of lead ({>=}1,700 ppm), added as PbO, results in intergranular cracking. Changing from reducing to oxidizing conditions at 2,000 ppm lead exacerbates cracking, as does the addition of sulphate and chloride ions. PbO is thought to enhance nickel dissolution at the grain boundaries producing Metallic lead in the process. Metallic lead itself is not thought to be the embrittling agent. Sulphate and chloride exacerbate the cracking because they form semi-protective films thereby focusing nickel dissolution in regions of film rupture.
- OSTI ID:
- 203806
- Report Number(s):
- CONF-950816-; ISBN 1-877914-95-9; TRN: 96:009772
- Resource Relation:
- Conference: 7. international symposium on environmental degradation of materials in nuclear power plants: water reactors, Breckenridge, CO (United States), 6-10 Aug 1995; Other Information: PBD: 1995; Related Information: Is Part Of Seventh international symposium on environmental degradation of materials in nuclear power systems -- Water reactors: Proceedings and symposium discussions. Volume 1; Airey, G.; Andresen, P.; Brown, J. [eds.] [and others]; PB: 664 p.
- Country of Publication:
- United States
- Language:
- English
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