ML042660231
| ML042660231 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/30/2004 |
| 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: ML042660231 (38) | |
Text
BWXT SERVICES, INC.
1140-025-02-24 190 BSE 100X Figure 7.3.3.3: Low magnification BSE micrograph showing the cracking that initiated from the exposed cladding surface (left side of figure). The maximum crack depth is approximately 0.055" below the cladding surface.
BWXT SERVICES, INC.
1140-025-02-24 191 SE 100X SE 1,000X Figure 7.3.3.4: SE micrographs of the circumferential cracking in the J-groove weld. The maximum circumferential cracking depth is approximately 0.032" below the surface. Cracking was interdendritic in nature.
BWXT SERVICES, INC.
1140-025-02-24 192 4X Figure 7.3.4.1: Macro photograph of the opened-up circumferential cracking in the J-groove weld at ~30o. The underside surface of the J-groove weld (in contact with RCS) is shown. Refer to Figures 5.6 and 5.8 for the sample location. The rectangular sample (A2A6A2C2) is secured to the round SEM stub with black carbon tape.
BWXT SERVICES, INC.
1140-025-02-24 193 SE 15X SE 200X Figure 7.3.4.2: SE micrographs showing the shallow circumferential cracking in the J-groove weld. Cracking was interdendritic.
BWXT SERVICES, INC.
1140-025-02-24 194 4X Figure 8.1.1.1: Macro photograph of sample A1B2. Refer to Figures 5.13 and 5.14 for the sample location. The white box shows area enlarged in Figure 8.1.1.2.
BWXT SERVICES, INC.
1140-025-02-24 195 Etched 18X Figure 8.1.1.2: Low magnification micrograph showing horizontal striations aligned with the major axis of the RV head low alloy steel plate (SA-533, Gr. B (mod), Cl. 1). The striations are due to the segregation of carbides, which promote a slightly faster local corrosion rate along the striations. Note that this micrograph is a mirror image of Figure 8.1.1.1.
BWXT SERVICES, INC.
1140-025-02-24 196 Etched 48X Figure 8.1.1.3: Higher magnification micrograph, which indicates a slightly faster local corrosion rate along the striations.
Etched 375X Figure 8.1.1.4: Micrograph showing the typical tempered martensitic microstructure of SA-533, Gr. B (mod), Cl. 1 low alloy steel plate.
BWXT SERVICES, INC.
1140-025-02-24 197 4X Figure 8.1.2.1: Macro photograph of metallurgical mount A1B4. Refer to Figures 5.13 and 5.14 for the sample location. The white box indicates the area shown at higher magnification in Figure 8.1.2.2.
BWXT SERVICES, INC.
1140-025-02-24 198 Etched 18X Figure 8.1.2.2: Higher magnification micrograph showing the horizontal striations aligned with the major axis of the RV head low alloy steel plate (SA-533, Gr. B (mod), Cl. 1). However, unlike Figure 8.1.1.3, the striations do not appear to promote a faster corrosion rate locally.
BWXT SERVICES, INC.
1140-025-02-24 199 Etched 48X Figure 8.1.2.3: At higher magnification, the local corrosion rate along the striations is increased only very slightly.
Etched 375X Figure 8.1.2.4: Micrograph showing the typical tempered martensitic microstructure of SA-533, Gr. B (mod), Cl. 1 low alloy steel plate.
BWXT SERVICES, INC.
1140-025-02-24 200 SE 18X SE 15X Figure 8.1.3.1: Low magnification SE micrographs of cavity wall surface near 90°. The surface contains generally round depressions measuring ~0.039" or less in diameter.
BWXT SERVICES, INC.
1140-025-02-24 201 SE 50X SE 150X Figure 8.1.3.2: Higher magnification micrographs of the cavity side wall near 90°.
BWXT SERVICES, INC.
1140-025-02-24 202 SE 100X SE 1,000X Figure 8.1.3.3: SE micrographs showing corrosion products on cavity side wall near 90°.
BWXT SERVICES, INC.
1140-025-02-24 203 Figure 8.2.1.1: Low magnification photographs showing macro etch results.
Arrows indicate corrosion grooves associated with corresponding micro-structural banding. Macro etch was performed on two surfaces of sample A1D2E ground with 400 grit paper. Etchant: 10% nital.
A1D2E (face perpendicular to cavity sidewall)
A1D2E (face parallel to cavity sidewall)
A1D1
- 1
BWXT SERVICES, INC.
1140-025-02-24 204 4X Figure 8.2.2.1: Macro photograph of metallurgical mount A1D2B1. Refer to Figures 5.13, 5.15, and 5.16 for the sample location. The white box indicates the area shown at higher magnification in Figure 8.2.2.2.
BWXT SERVICES, INC.
1140-025-02-24 205 Etched 18X Figure 8.2.2.2: Slightly higher magnification micrograph showing the horizontal striations aligned with the major axis of the RV head low alloy steel plate (SA-533, Gr.
B (mod), Cl. 1). Striations appear to be caused by a very slightly faster local corrosion rate. Note that this micrograph is a mirror image of Figure 8.2.2.1.
BWXT SERVICES, INC.
1140-025-02-24 206 Etched 48X Figure 8.2.2.3: Higher magnification detail of Figure 8.2.2.2, which suggests a slightly faster local corrosion rate along the striations.
Etched 375X Figure 8.2.2.4: Micrograph showing the typical tempered martensitic microstructure of SA-533, Gr. B (mod), Cl. 1 low alloy steel plate.
BWXT SERVICES, INC.
1140-025-02-24 207 4X Figure 8.2.3.1: Macro photograph of metallurgical mount A1D2D1. Refer to Figures 5.13, 5.15, and 5.16 for the sample location. The white box indicates the area shown at higher magnification in Figure 8.2.3.2.
BWXT SERVICES, INC.
1140-025-02-24 208 Etched 18X Figure 8.2.3.2: Higher magnification detail of Figure 8.2.3.1 showing the horizontal striations aligned with the major axis of the RV head low alloy steel plate (SA-533, Gr.
B (mod), Cl. 1). Striations appear to be caused by a very slightly faster local corrosion rate.
BWXT SERVICES, INC.
1140-025-02-24 209 Etched 48X Figure 8.2.3.3: Higher magnification detail of Figure 8.2.3.2, which suggests a slightly faster local corrosion rate along the striations.
Etched 375X Figure 8.2.3.4: Micrograph showing typical tempered martensitic microstructure of SA-533, Gr. B (mod), Cl. 1 low alloy steel plate.
BWXT SERVICES, INC.
1140-025-02-24 210 SE 18X BSE 18X Figure 8.2.4.1: SE (top) and BSE (bottom) micrographs of the cavity wall surface near 270°. The surface contained rounded depressions measuring 0.020" in diameter or less. Orientation of micrographs: lower portion of cavity to the right and upper portion to the right. Nozzle #3 is closer to lower edge of micrograph.
BWXT SERVICES, INC.
1140-025-02-24 211 SE 15X SE 50X Figure 8.2.4.2: SE micrographs of cavity side wall near 270°. These micrographs suggest that larger (~1 mm dia.) shallower depressions are caused by acid boiling and smaller (~0.3 mm dia.) deeper depressions are caused by inclusions.
BWXT SERVICES, INC.
1140-025-02-24 212 SE 150X SE 1,500X Figure 8.2.4.3: Higher magnification SE micrograph showing corrosion products on cavity side wall near 270°.
BWXT SERVICES, INC.
1140-025-02-24 213 Figure 8.3.1.1: Macro photograph of metallographic mount A2A7D. Refer to Figures 5.1 and 5.11 for the sample location.
Low alloy steel Stainless steel cladding Corrosion undercut
BWXT SERVICES, INC.
1140-025-02-24 214 Etched 48X Figure 8.3.1.2: Micrograph showing the edge of the exposed cladding in the undercut region. Note: the micrograph is a mirror image of the macrograph in Figure 8.3.1.1.
Etched 48X Figure 8.3.1.3: Micrograph showing intergranular attack (IGA) and intergranular or interdendritic cracking in the cladding. The maximum depth of the crack tip is approximately 0.047" below the exposed cladding surface.
BWXT SERVICES, INC.
1140-025-02-24 215 Etched 100X Etched 375X Figure 8.3.1.4: Micrographs showing intergranular attack (IGA) and intergranular or interdendritic cracking on the exposed cladding surface.
BWXT SERVICES, INC.
1140-025-02-24 216 Etched 100X Etched 375X Figure 8.3.1.5: Micrographs showing the interface between the low alloy steel (above the fusion line) and the stainless steel cladding (below the fusion line).
BWXT SERVICES, INC.
1140-025-02-24 217 Etched 375X Etched 375X Figure 8.3.1.6: Micrographs showing typical stainless steel cladding microstructure.
The interdendritic solidification structure is delineated by small pools (or islands) of ferrite in an austenitic matrix.
BWXT SERVICES, INC.
1140-025-02-24 218 4X Figure 8.3.2.1: Macro photograph of metallographic mount A2A7F.
Refer to Figures 5.1 and 5.11 for the sample location.
Low alloy steel Stainless steel cladding
BWXT SERVICES, INC.
1140-025-02-24 219 Etched 41X Figure 8.3.2.2: Micrograph showing the exposed cladding surface. A slight undercut is evident in the low alloy steel. Note: the micrograph is a mirror image of the macrograph in Figure 8.3.2.1.
BWXT SERVICES, INC.
1140-025-02-24 220 Etched 100X Etched 375X Figure 8.3.2.3: Micrographs showing intergranular attack (IGA) and intergranular or interdendritic cracking. The maximum depth of the crack tip is approximately 0.024" below the exposed cladding surface.
BWXT SERVICES, INC.
1140-025-02-24 221 Etched 100X Etched 375X Figure 8.3.2.4: Micrographs showing the interface between the low alloy steel (above the fusion line) and the stainless steel cladding (below the fusion line).
BWXT SERVICES, INC.
1140-025-02-24 222 Etched 100X Etched 375X Figure 8.3.2.5: Micrographs showing the typical stainless steel cladding microstructure. The interdendritic solidification structure is delineated by small pools (or islands) of ferrite in an austenitic matrix.
BWXT SERVICES, INC.
1140-025-02-24 223 4X Figure 8.3.3.1: Macro photograph of metallographic mount A2A7K.
Refer to Figures 5.1 and 5.11 for the sample location.
Low alloy steel Stainless steel cladding Corrosion undercut
BWXT SERVICES, INC.
1140-025-02-24 224 Etched 48X Figure 8.3.3.2: Micrograph showing the edge of the exposed cladding in the undercut region. Note: the micrograph is a mirror image of the macrograph in Figure 8.3.3.1.
Etched 48X Figure 8.3.3.3: Micrograph showing minor intergranular attack (IGA) in the exposed cladding surface.
BWXT SERVICES, INC.
1140-025-02-24 225 Etched 100X Etched 375X Figure 8.3.3.4: Micrographs showing the interface between the low alloy steel (above the fusion line) and the stainless steel cladding (below the fusion line).
BWXT SERVICES, INC.
1140-025-02-24 226 Etched 100X Etched 375X Figure 8.3.3.5: Micrographs showing the typical stainless steel cladding microstructure. The interdendritic solidification structure is delineated by small pools (or islands) of ferrite in an austenitic matrix.
DISTRIBUTION (COMPANY LIMITED): This information is freely available to all Company personnel. Written approval by the sponsoring unit is required only if release outside the Company is requested.
BWXS Framatome ANP, Inc.
FENOC J. W. Hyres (2)
Hongqing Xu (4)
Todd Pleune (10)
Project File (3)
Steve Fyfitch (1)
KEY WORDS: DAVIS-BESSE, REACTOR VESSEL HEAD, BORIC ACID CORROSION, PRIMARY WATER STRESS CORROSION
- CRACKING, PWSCC, STAINLESS STEEL CLADDING, TENSILE TESTING, ELECTRICAL DISCHARGE MACHINING, SCANNING ELECTRON MICROSCOPY, SEM, METALLOGRAPHY, ALLOY 600, CONTROL ROD DRIVE MECHANISM NOZZLES, CRDM NOZZLES, ALLOY 182, J-GROOVE WELD, FLUORESCENT PENETRANT TESTING, DENTAL MOLDS