Characterization of deposits in Dampierre-1 steam generator support plate crevices
Westinghouse and EDF have independently characterized the chemical and physical properties of tube support plate crevice assemblies removed from a retired steam generator at the Dampierre-1 plant. In addition to obtaining SEM photomicrographs at numerous crevice locations, the crevice chemistry was evaluated by EDS, EPMA, ICP, and X-ray diffraction. The crevice porosity distribution was determined by image analysis of the photomicrographs. The Westinghouse evaluations found considerable radial and axial variation in both the porosity and constituent distributions. The porosity was reduced at the tube surface and along the edges of the crevice by precipitation of bulk contaminants, while it was reduced adjacent to the tube support plate by the precipitation of dissolved iron emanating from the corrosion of the tube support plate. Largely because of subtle differences in the regions selected for examination, the EDF evaluation found less porosity reduction and a more uniform constituent distribution. Significant porosity reductions, either at the tube surface or along the crevice boundary are likely to reduce the sensitivity of the tube corrosion kinetics to changes in the bulk water chemistry.
- OSTI ID:
- 203821
- Report Number(s):
- CONF-950816-; ISBN 1-877914-95-9; TRN: 96:009787
- 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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