ML042660365
| ML042660365 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/01/2004 |
| From: | Hyres J BWXT, BWXT Services |
| To: | Framatome ANP, Office of Nuclear Reactor Regulation |
| References | |
| ORNL/NRC/LTR-04/15 1140-025-02-24 | |
| Download: ML042660365 (28) | |
Text
BWXT SERVICES, INC.
1140-025-02-24 122 100X 375X Figure 6.1.1.5: Typical clad microstructure near RCS side surface of the cladding. No intergranular attack (IGA) was present.
BWXT SERVICES, INC.
1140-025-02-24 123 SEM micrograph showing EDS locations.
EDS results for Area 1.
Figure 6.1.2.1: SEM micrograph showing the three deepest cracks in A2A7M. Crack tips are 0.042" to 0.069" (1.1 to 1.75 mm) below the surface. It is noted that these three crack tips are at approximately the same distance of 0.199" (5.06 mm) from the underside surface. EDS scans of areas 1, 2, and 3 and line scans 1 and 2 (not included) indicated a generally uniform chemical composition (including Cr content) across the cladding thickness.
BWXT SERVICES, INC.
1140-025-02-24 124 EDS results for Area 2.
EDS results for Area 3.
Figure 6.1.2.1 (cont.): EDS results for Areas 2 and 3.
BWXT SERVICES, INC.
1140-025-02-24 125 100X 300X Figure 6.1.2.2: SEM micrographs showing interdendritic crack path along the elongated ferrite pools.
BWXT SERVICES, INC.
1140-025-02-24 126 Figure 6.2.1.1: 4X macro photograph of metallurgical mount A2A7N.
Refer to Figure 5.11 for the sample orientation.
Exposed cladding surface RCS side (underside of cladding)
BWXT SERVICES, INC.
1140-025-02-24 127 Etched 48X Figure 6.2.1.2: Micrograph of a crack observed on A2A7N. The crack tip is estimated to be approximately 0.036" (0.91 mm) below the surface.
BWXT SERVICES, INC.
1140-025-02-24 128 100X 375X Figure 6.2.1.3: Micrographs showing intergranular attack (IGA) and intergranular cracking on the exposed stainless steel cladding.
BWXT SERVICES, INC.
1140-025-02-24 129 100X 375X Figure 6.2.1.4: Typical clad microstructure in the mid-thickness of the cladding.
BWXT SERVICES, INC.
1140-025-02-24 130 100X 375X Figure 6.2.1.5: Typical clad microstructure near RCS side surface of the cladding. No intergranular attack (IGA) was present.
BWXT SERVICES, INC.
1140-025-02-24 131 SEM micrograph showing EDS locations.
EDS results for Area 1.
Figure 6.2.2.1: SEM micrograph showing the three deepest cracks in A2A7N. The maximum crack depth was approximately 0.056" (1.42 mm). EDS scans of areas 1, 2, and 3 and lines 1 and 2 (not included) indicated a generally uniform chemical composition (including Cr content) across the cladding thickness.
BWXT SERVICES, INC.
1140-025-02-24 132 EDS results for Area 2.
EDS results for Area 3.
Figure 6.2.2.1 (cont.): EDS results for Areas 2 and 3.
BWXT SERVICES, INC.
1140-025-02-24 133 SE 500X BSE 500X Figure 6.2.2.2: Higher magnification SEM micrographs of crack tip, showing the interdendritic crack path along the elongated ferrite pools.
BWXT SERVICES, INC.
1140-025-02-24 134 Sample A2A7S Knoop Microhardness 0.0 50.0 100.0 150.0 200.0 250.0 300.0 0.000 0.050 0.100 0.150 0.200 0.250 0.300 Distance from Upper Clad Surface, inches Microhardness, HK Figure 6.3.1.1: 4X macro photograph of metallurgical mount A2A7S. Refer to Figure 5.11 for the sample orientation. Knoop microhardness values exhibited lower hardness readings toward the exposed clad side (left side of graph), which was in contrast to A2A7M.
Exposed cladding surface RCS side (underside of cladding)
BWXT SERVICES, INC.
1140-025-02-24 135 100X 375X Figure 6.3.1.2: Micrographs showing intergranular attack (IGA) and intergranular or interdendritic cracking on the exposed stainless steel cladding.
BWXT SERVICES, INC.
1140-025-02-24 136 As-polished 48X Etched 48X Figure 6.3.1.3: Micrographs of cracking observed on sample A2A7S.
Different cracks are shown.
BWXT SERVICES, INC.
1140-025-02-24 137 100X 375X Figure 6.3.1.4: Typical clad microstructure in the mid-thickness of the cladding.
BWXT SERVICES, INC.
1140-025-02-24 138 100X 375X Figure 6.3.1.5: Typical clad microstructure near RCS side surface of the cladding. No intergranular attack (IGA) was present.
BWXT SERVICES, INC.
1140-025-02-24 139 SEM micrograph showing EDS locations.
EDS results for Area 1.
Figure 6.3.2.1: SEM micrograph of the three deepest cracks in A2A7S. The maximum crack depth was approximately 0.056 (1.42 mm). These three crack tips are approximately the same distance from the underside surface. EDS scans of areas 1, 2, and 3 and lines 1 and 2 (not included) indicated a generally uniform chemical composition (including Cr content) across the cladding thickness.
BWXT SERVICES, INC.
1140-025-02-24 140 EDS results for Area 2.
EDS results for Area 3.
Figure 6.3.2.1 (cont.): EDS results for Areas 2 and 3. Note that the Cr peak was set at full screen height for Area 2.
BWXT SERVICES, INC.
1140-025-02-24 141 BSE 50X BSE 300X Figure 6.3.2.2: Higher magnification SEM micrographs of crack tip, showing the interdendritic crack path along the elongated ferrite pools.
BWXT SERVICES, INC.
1140-025-02-24 142 SE 500X SE 500X Figure 6.3.2.3: Secondary electron SEM images of crack tip, showing the interdendritic crack path along the elongated ferrite pools.
BWXT SERVICES, INC.
1140-025-02-24 143 Exposed cladding surface Figure 6.4.1.1: Low magnification SEM mosaic showing the opened main crack (sample A2A7-L1A). Refer to Figures 5.11 and 5.12 for the sample location. The exposed cladding surface is oriented downward in the SEM micrographs.
BWXT SERVICES, INC.
1140-025-02-24 144 BSE 50X BSE 500X Figure 6.4.1.2: Near mosaic area A. Heavy deposits are present toward the exposed side of the cladding (darker contrast in BSE micrograph).
Fracture morphology is interdendritic in nature.
BWXT SERVICES, INC.
1140-025-02-24 145 SE 50X SE 500X Figure 6.4.1.3: Near mosaic area B. Cracking is intergranular/interdendritic.
BWXT SERVICES, INC.
1140-025-02-24 146 BSE 150X SE 500X Figure 6.4.1.4: Near mosaic area "C". Fracture mode is intergranular or interdendritic for in-service cracking and ductile tearing for lab opened-up fracture.
BWXT SERVICES, INC.
1140-025-02-24 147 BSE 50X SE 300X Figure 6.4.1.5: Near mosaic area "D". Fracture mode is intergranular or interdendritic for in-service cracking and ductile tearing for lab opened-up fracture (upper right).
BWXT SERVICES, INC.
1140-025-02-24 148 BSE 25X SE 500X Figure 6.4.1.6: Near mosaic area "E". Cracking is intergranular/interdendritic.
BWXT SERVICES, INC.
1140-025-02-24 149 SE 1,000X EDS results for area 1 above.
Figure 6.4.1.7: SEM micrograph and EDS results for deposited region near area "E".
The corrosion deposits contained carbon, oxygen, along with iron, aluminum, silicon, and chromium. Possible trace levels of nickel and chlorine were also detected in this area.