ML042580468
| ML042580468 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/31/2004 |
| From: | Framatome ANP |
| To: | Office of Nuclear Reactor Regulation, Pacific Gas & Electric Co |
| References | |
| DCL-04-112 51-5046570-01 | |
| Download: ML042580468 (151) | |
Text
Enclosure 5 PG&E Letter DCL-04-112 ENCLOSURE 5 SPECIAL REPORT 04-02 FRAMATOME-ANPREPORT 51-5046570-01 "EXAMINATION OF DIABLO CANYON UNIT 1 STEAM GENERATOR TUBE NO.
R20C54, FINAL REPORT, AUGUST 2004"
Examination of Diablo Canyon Unit 1 Steam Generator Tube No. R20C54 51-5046570-01 Final Report, August 2004 Prepared for Pacific Gas & Electric Company AW' AR EVA
20440-11 (3/30/2004)
DA ENGINEERING INFORMATION RECORD AR EVA Document Identifier 51 -
5046570 - 01 Title EXAMINATION OF DIABLO CANYON UNIT 1 STEAM GENERATOR TUBE NO. R20C54 PREPARED BY:
REVIEWED BY:
Name P.A. SHERBURNE Name C.E. MARTJN/JR.
2 Signature Va Date 8/30/2004 Signature D(t e Date
/
Technical Manager Statement: Initials Reviewer is Independent.
L. 5.
Remarks:
Sections of steam generator (SG) tube no. R20C54 were removed from Diablo Canyon Power Plant Unit 1 (DCPP-1) during the 1 R12 outage in April 2004. This tube was removed from SG '11 to meet the three-cycle frequency requirement of EPRI Report No. 1006255. Tube no. R20C54 had 3 eddy current (EC) indications representative of axially oriented OD stress corrosion cracks (ODSCC) at the Is? TSP (I H) intersection.
Laboratory -examination of the pulled tube was subsequently conducted in support of NRC GL 95-05 requirements for voltage-based alternate repair criteria (ARC) for axial ODSCC. The primary objectives of the examination were the following:
To physically characterize the tube degradation for correlation with field NDE results and to verify that the degradation morphology is consistent with the assumptions made in NRC GL 95-05.
- To determine the effect of degradation on the burst strength of the tubing and the leak rate under main steam line break (MSLB) conditions.
These examinations included receipt inspection and verification of identity, eddy current testing,,dimensional measurements, ambient temperature leak rate and burst testing, visual and stereovisual'inspections and photography, scanning electron microscopy (SEM) including energy dispersive spectroscopy'(EDS) and wavelength dispersive spectroscopy (WDS), fractography, metallography, and tensile testing.
Results of the laboratory examinations are described in this report.
Framatome ANP, Inc., an AREVA and Siemens company Page I
of 149
51-5046570-01 Page 2 of 149 RECORD OF REVISION DATE REV.
SECTION DESCRIPTION 8/03/2004 00 All Original Release 8/30/2004 01 Footnote, p.13 Section 2.2, p.16 Section 2.8, p.20 Section 2.9, p.21 Section 3, p.25 Section 4, p.27 Section 5, p.28 Table 3, p.30 Table 13, p.37 Figure 59, p.94 Figure 76, p.105 The report date was corrected.
The +Point coil voltage for the largest indication was changed to 4.OOV from 3.99V to be consistent with the value reported in the Framatome Data Management System (FDMS).
In the 2H TSP discussion, the axial extent of corrosion was changed from 0.86 inches to 0.795 inches to reflect axial length data adjusted for curvature of the burst fracture face.
Discussion was added to the paragraphs for R20C54-5B3 (2H TSP) to explain the curvature adjustment made to measured lengths for the axial corrosion profile. Reference 8 was added.
The summary of examinations was revised to reflect the use of adjusted corrosion length data for the 2H TSP corrosion profile.
Changed reference to Ref. 9 from Ref.-8.
Reference 8 (new) was added to the list of references.
FDMS data was added to Table 3.
A column for adjusted length data was added to Table 13.
A note was added to qualify the measurements shown in the figure.
Figure 76 was replaced with a new figure showing the depth of IGSCC plotted against adjusted axial distance.
A AR EVA 51-5046570-01 Examination of Diablo Canyon Unit I Steam Generator Tube No. R20C54 51-5046570-01 Final Report, August 2004 Framatome ANP, Inc.
- 155 Mill Ridge Road. Lynchburg, Virginia 24502-4341 434.832.3000. www.frarmatech.conm 3
A A R EVA 51-5046570-01 Citations This report was prepared by Framatome ANP, Inc.
155 Mill Ridge Road Lynchburg, Virginia 24502-4341 Principal Investigator P. A. Sherburne, P.E.
Advisory Engineer Examination of Diablo Canyon Unit I Steam Generator Tube No. R20C54, August 2004, Framatome ANP, Inc. Document No. 51-5046570-01.
Acknowledgements The author would like to acknowledge and thank the following people for their significant contributions to this project: Jim Begley, Jeff Fleck, Mark Harris, B.J. Hefner, AC Martin, George Owen, Greg Pillow, Mike Pop, and Steve Jensen and Woody White of BWXT.
4
A AR EVA 51-5046570-01 EXECUTIVE
SUMMARY
Sections of steam generator (SG) tube no. R20C54 were removed from Diablo Canyon Power Plant Unit 1 (DCPP-1) during the 1R12 outage in April 2004. This tube was removed from SG 11 to meet the three-cycle frequency requirement of EPRI Report No. 1006255.'
Tube no. R20C54 had 3 eddy current (EC) indications representative of axially oriented OD stress corrosion cracks (ODSCC) at the is TSP (1 H) intersection.
Laboratory examination of the pulled tube was subsequently conducted in support of NRC GL 95-05 requirements for voltage-based alternate repair criteria (ARC) for axial ODSCC.
The primary objectives of the examination were the following:
To physically characterize the tube degradation for correlation with field NDE results and to verify that the degradation morphology is consistent with the assumptions made in NRC GL 95-05.
To determine the effect of degradation on the burst strength of the tubing and the leak rate under main steam line break (MSLB) conditions.
These examinations included receipt inspection and verification of identity, eddy current testing, dimensional measurements, ambient temperature leak rate and burst testing' visual and stereovisual inspections and photography, scanning electron' microscopy (SEM) including energy dispersive spectroscopy (EDS) and wavelength dispersive spectroscopy (WDS), fractography, metallography, and tensile testing.
The laboratory examinations confirmed axial intergranular stress corrosion -cracking (IGSCC) in the 1H TSP region of this tube. A through wall defect was present in the 1H TSP region as confirmed by leak rate testing and later by SEM fractography. The total axial extent and through wall extent of this defect were 0.70 and 0.12 inches, respectively. "In addition, two'smaller IGSCC cracks were present at other circumferential'locations. :The burst pressure for this section was 5,819 psi. The corresponding free span region without defects burst at 11,695 psi.
The burst pressure for the 2H TSP section was 10,428 psi. Post-burst inspection revealed two patches of intergranular corrosion that had not been 'detected during 'eddy current inspection prior to tube pull.
These patches exhibited grid-like patterns of axial: and circumferential cracks, dubbed by the industry as "cellular corrosion" by virtue of its appearance. Cellular corrosion is generally shallow and transitions to predominantly axial cracks -as the cracking progresses. This behavior was confirmed in this examination by grinding radially through the two patches of corrosion. The maximum depth of the corrosion in the 2H burst region was found to be less than 48% through wall. A review of the eddy current data records confirmed that the corrosion was not detected by either the bobbin or rotating eddy current probes during the field inspection.
On.review, a small, single volumetric indication (SVI) was found in the post-pull rotating coil data.
SEM/EDSNWDS'analysis revealed the presence of sulfur on the "2H burst rupture surface.
Sulfur is known to be detrimental to Alloy 600 and has been previously implicated in intergranular corrosion.
5
A AR EVA 51-5046570-01 Table of Contents Section Page I
Introduction........................
13 1.1 Background.......................
13 1.2 Examinations Performed.......................
13 1.3 QualityAssurance......................
14 2
Tube Failure Analysis......................
15 2.1 Receipt Visual Inspection..................
15 2.2 Eddy Current Inspection..................
15 2.3 Leak Rate Testing..................
17 2.4 Furnace Oxidation................................................... 17 2.5 Post Oxidation Inspection..................
18 2.6 Sectioning Diagrams..................
18 2.7 Burst Testing..................
18 2.8 Macro Photography/Stereovisual Examination of Post-Burst Regions........... 19 2.9 SEM Fractography..................
20 2.10 EDS Analyses..................
21 2.11 Defect Metallography..................
22 2.12 Material Properties..................
24 3
Summary of Laboratory Examinations.............................
25 4
Conclusions.............................
27 5
References.............................
28 6
A AR EVA 51-5046570-01 List of Tables Page
- 1.
Diablo Canyon Unit 1 SG 11 Tube Receipt Inspection Summary............................... 29
- 2.
Bobbin Eddy Current Inspection Results Summary.................................................... 30
- 3.
Rotating Coil Eddy Current Inspection Summary........................................................ 30
- 4.
Review of Rotating Coil Eddy Current Data Acquired prior to and following Tube Pull.....................................................
30
- 5.
Summary of Leak Rate Tests.....................................................
30
- 6.
Rotating Coil Eddy Current Inspection Pre and Post Leak Comparisons.................... 31
- 7.
Room Temperature Burst Test Results.....................................................
31
- 8.
Burst Test Dimensional Measurements - Control Specimen...................................... 32
- 9.
Burst Test Dimensional Measurements - R20C54-3B2 (1 H)...................................... 33
- 10.
Burst Test Dimensional Measurements - R20C54-4B (Free Span)............................ 34
- 11.
Burst Test Dimensional Measurements - R20C54-5B3 (2H)....................................... 35
- 12.
Defect Burst Specimen Fractography Measurements - R20C54-3B (1H TSP)........... 36
- 13.
Defect Burst Specimen Fractography Measurements - R20C54-5B (2H TSP)............ 37
- 14.
Depth (in inches) of Radial Grinds in the 2H TSP Specimens.................................... 38
- 15.
Tensile Test Results..........................................................
38
- 16.
Bulk Chemistry Analysis.........................................................
38
- 17.
Summary Material Properties for Tube No. R20C54................................................... 39
- 18.
Depth of IGSCC near Axial Centerline of 1 H TSP...................................................... 40
- 19.
Depth of IGSCC at -0.1 inch above Axial Centerline of 1H TSP................................ 41 7
A AREVA 51-5046570-01 List of Figures Page
- 1.
Tube pull diagram - SG 11 tube no. R20C54............................................................ 42
- 2.
Receipt photograph of 1 H TSP intersection (section 3) at 00...................................... 43
- 3.
Room temperature leak rate for SG 11 tube no. R20C54, section 3 (1 H TSP)........... 43
- 4.
Axial crack NDE profile at 190 (SAI #1) at 1H TSP location for tube no. R20C54....... 44
- 5.
Axial crack NDE profile at 330° (SAI #2) at 1 H TSP location for tube no. R20C54..... 44
- 6.
Axial crack NDE profile at 292° (SAI #3) at 1 H TSP location for tube no. R20C54..... 45
- 7.
Post oxidation photograph of axial crack at -19° in 1 H TSP intersection of tube section R20C54-3 (7.6X)........................
45
- 8.
1H TSP Region at 0° (1.7X).......................
46
- 9.
1 H TSP Region at 450 (1.7X).......................
47
- 10.
1 H TSP Region at 900 (1.7X).......................
48
- 11.
1 H TSP Region at 1350 (1.7X).......................
49
- 12.
1 H TSP Region at 1800 (1.7X).......................
50
- 13.
1 H TSP Region at 2250 (1.7X).......................
51
- 14.
1 H TSP Region at 2700 (1.7X).......................
52
- 15.
1 H TSP Region at 315° (1.7X).......................
53
- 16.
2H TSP Region at 00 (1.7X).......................
54
- 17.
2H TSP Region at 450 (1.7X).......................
55
- 18.
2H TSP Region at 900 (1.7X).......................
56
- 19.
2H TSP Region at 1350 (1.7X)......................
57
- 20.
2H TSP Region at 1800 (1.7X).....................
58
- 21.
2H TSP Region at 2250 (1.7X).....................
59
- 22.
2H TSP Region at 2700 (1.7X).....................
60
- 23.
2H TSP Region at 3150 (1.7X).....................
61
- 24.
Axial crack in 1 H TSP region of R20C54-3B at -1190 (25.7X)...................................... 62
- 25.
Small axial cracks near 2850 in 1 H TSP region (83X)............................................... 63
- 26.
Overall sectioning diagram for R20C54-3 (1 H TSP)..............................................
64
- 27.
Sectioning of R20C54-3B2 for fractography and metallography................................. 64
- 28.
Overall sectioning diagram for R20C54-4 (free span).............................................. 65
- 29.
Sectioning of R20C54-4B2 burst region for stereovisual exam.................................. 65 8
A AR EVA 51-5046570-01
- 30.
Overall sectioning diagram for R20C54-5 (2H TSP).................................................. 66
- 31.
Sectioning of R20C54-5B3B for fractography and metallography............................... 66
- 32.
1 H TSP region at 0° after burst testing (1.7X)............................................................ 67
- 33.
1 H TSP region at 450 after burst testing (1.7X)........................................................... 68
- 34.
1 H TSP region at 90° after burst testing (1.7X)........................................................... 69
- 35.
1 H TSP region at 1350 after burst testing (1.7X)......................................................... 70
- 36.
1 H TSP region at 1800 after burst testing (1.7X)......................................................... 71
- 37.
1 H TSP region at 2250 after burst testing (1.7X)..........................................................
72
- 38.
i H TSP region at 2700 after burst testing (1.7X)............................................. I............. 73
- 39.
1 H TSP region at 3150 after burst testing (1.7X).......................................................... 74
- 40.
Burst centered at 19° in 1 H TSP region (1.7X)........................................................... 75
- 41.
Oxidized corrosion area on counterclockwise burst rupture surface of 1 H TSP (8X).. 76
- 42.
Oxidized corrosion area on clockwise burst rupture surface of 1 H TSP (8X).............. 77
- 43.
Secondary crack near 3500 in 1 H TSP, extending from -0.1 inches to -0.2 inches from the bottom of the TSP region (1 6.6X).78
- 44.
Secondary cracks near 3550 in 1 H TSP, extending from -0.5 inches to -0.7 inches from the bottom of the TSP region (16.6X).......................................... 79
- 45.
Fish mouth rupture at 3500 in free span section (1.7X)............................................... 80
- 46.
2H TSP region at O° after burst testing (1.7X)............................................................ 81
- 47.
2H TSP region at 450 after burst testing (1.7X)............................................................ 82
- 48.
2H TSP region at 900 after burst testing (1.7X))......................................................... 83
- 49.
2H TSP region at 1350 after burst testing (1.7X)......................................................... 84
- 50.
2H TSP region at 1800 after burst testing (1.7X).......................................................... 85
- 51.
2H TSP region at 2250 after burst testing (1.7X)......................................................... 86
- 52.
2H TSP region at 2700 after burst testing (1.7X)......................................................... 87
- 53.
2H TSP region at 3150 after burst testing (1.7X)......................................................... 88
- 54.
Burst centered at 300 in 2H TSP region (1.7X)........................................................... 89
- 55.
Counterclockwise burst rupture surface in 2H TSP (8X)............................................. 90
- 56.
Apex of counterclockwise burst rupture surface in 2H TSP (16.6X).................... I........ 91
- 57.
Clockwise burst rupture surface in 2H TSP (8X)......................................................... 92
- 58.
Apex of clockwise burst rupture surface in 2H TSP (16.6X)..
93
- 59.
Areas of intergranular corrosion in 2H TSP............................................................
94
- 60.
SEM mosaics of 1H burst rupture surface (bottom to left).......................................... 95
- 61.
SE image of bottom edge of IGSCC on burst rupture surface of 1 H TSP (50X).......... 96 9
A5 AR EVA 51-5046570-01
- 62.
BSE image of bottom edge of IGSCC on burst rupture surface of 1 H TSP (5OX)....... 96
- 63.
SE image showing transition to 100% TW IGSCC on burst rupture surface of 1 H TSP (50X)............................................................
97
- 64.
Detail of transition area shown in box in Figure 56 (15OX).......................................... 97
- 65.
BSE image of transition arfea to 100% IGSCC on burst rupture surface of 1 H TSP (50X).98
- 66.
SE image of top edge of IGSCC on burst rupture surface of 1 H TSP (5OX).99
- 67.
BSE image of top edge of IGSCC on burst rupture surface of 1 H TSP (5OX).99
- 68.
- 1) in 1 H TSP.100
- 69.
SEM mosaics of 2H burst rupture surface (bottom to left).101
- 70.
SE image of bottom edge of IGSCC on burst rupture surface of 2H TSP (5OX).
102
- 71.
BSE image of bottom edge of IGSCC on burst rupture surface of 2H TSP (50X).
102
- 72.
SE image of central region of burst rupture surface of 2H TSP (50X).103
- 73.
BSE image of central region of burst rupture surface of 2H TSP (5OX).103
- 74.
SE image of top edge of IGSCC on burst rupture surface of 2H TSP (5OX).104
- 75.
BSE image of top edge of IGSCC on burst rupture surface of 2H TSP (50X).
104
- 76.
Plot of depth of intergranular corrosion in 2H TSP (Section R20C54-5B3).105
- 77.
Free span burst rupture surface (lOX).............................................................
106
- 78.
Typical non-corroded ductile area on free span burst rupture surfacel02
- SE image (500X).106 79.
EDS analysis of area on 2H burst rupture surface.107 80 Typical copper colored deposits in free span areas (1.7X).108
- 81.
SEM/EDS analysis of copper colored deposits on tube OD...................................... 109
- 82.
53% TW defect near 2980 in centerline of 1 H TSP, corresponding to approximate location of secondary eddy current indication (46X)............................. 110
- 83.
Etched microstructure of crack shown in Figure 83 (480X).110
- 84.
40% TWV defect near 330° at centerline plus 0.10 inches of 1H TSP, corresponding to approximate location of secondary eddy current indication (59X).11
- 85.
Etched microstructure of cracking shown in Figure 85 (175X).11
- 86.
Overall mosaic of 5B3B31 (first face) (11.2X).112
- 87.
Area "A" in Figure 86 (146X).113
- 88.
Area 'B" in Figure 87.(99X).113
- 89.
Area UC" in Figure 80 (99X)............
1.........................
114
- 90.
Overall mosaic of 5B3BBI (second face) -(10.6X).115
- 91.
AreaKA"in Figure 90 (146X).116 10
A AR EVA 51-5046570-01
- 92.
Area "B" in Figure 90 (146X) 116
- 93.
Area "C" in Figure 90 (99X) 117
- 94.
Overall mosaic of 5B3BB1 (third face)
(1 0.OX).....................................................
118
- 95.
Area 'A" in Figure 94 (146X) 119
- 96.
Area 'B" in Figure 94 (146X).....................................................
119
- 97.
Overall mosaic of 5B3BB1 (fourth face)
(9.9X).....................................................
120
- 98.
Area "A" in Figure 97 (99X) 121
- 99.
Area 'B" in Figure 97 (146X) 121 100.
Corrosion area near top of 2H TSP in 5B3B2A (first face). (14.6X).
................... 122 101.
Overall mosaic of corrosion near bottom end of 2H TSP 123 in 5B3B2A (first face) (12.6X).....................................................
123..
1 102.
Area "A" in Figure 101 (99X)
.................................................... 124 103.
Area "B" in Figure 101 (99X) 124 104.
Corrosion area near top of 2H TSP in 5B3B2A (second face) (14.6X).
................. 125 105.
Overall mosaic of corrosion near bottom end of 2H TSP in 5B3B2A (second face) (13.7X)....................................................
126 106.
Area "A" in Figure 105 (99X) 127 107.
Area "B" in Figure 105 (146X)....................................................
127 108.
Corrosion area near top of 2H TSP in 5B3B2A (third face) (14.6X).
................... 128 109.
Overall mosaic of corrosion near bottom end of 2H TSP 129 in 5B3B2A (third face) (12.8X).....................................................
- 129 110.
Area "A" in Figure 109 (99X) 130 111.
Area "B" in Figure 109 (99X)
...................................... 130 112.
Corrosion area near top of 2H TSP IN 5B3B2A (fourth face) (14.6X).
.................. 131 113.
Area 'A" in Figure 112 (99X)....................................................... 131 114.
Overall mosaic of corrosion near bottom end of 2H TSP in 5B3B2A (fourth face) (17.5X)......................................................
132 115.
Area "A" in Figure 114 (146X) 133 116.
Corrosion area near top of 2H TSP in 5B3B2A (fifth face) (14.6X)
.................... 134 117.
Detail of area shown in box in Figure 116 (198X).....................................................
134 118.
Bottom end of 2H TSP in 5B3B2A (fifth face) (14.6X) 135 119.
Detail of area shown in box in Figure 118 (496X).....................................................
135 120.
Overall mosaic of corrosion on 5B3B2C (first face) (10.OX).
.................................. 136 121.
Area "A" in Figure 120 (492X).............................................
137 122.
Area "B" in Figure 120 (492X).............................................
137 11
'A AR EVA 51-5046570-01 123.
Area "C" in Figure 120 (199X)................................................
138 124.
Area "D" in Figure 120 (199X).................................................
138 125.
Overall mosaic of corrosion on 5B3B2C (second face) (9.9X).................................. 139 126.
Area "A" in Figure 125 (99X).................................................
140 127.
Area "B" in Figure 125 (146X)................................................
140 128.
Overall mosaic of corrosion on 5B3B2C (third face) (1 1.7X)..................................... 141 129.
Area "A" in Figure 128 (99X)................................................
142 130.
Last remnants of corrosion shown previously in lower left of Figure 125 (third face now) (49.6X)................................................
142 131.
Last remnants of corrosion shown previously in upper portion of Figure 128 (fourth face now) (146X)................................................
143 132.
Overall mosaic of 5B3B2E (first face) (1 0.4X)................................................
144 133.
Area "A" in Figure 132 (146X).................................................
145 134.
Area "B" in Figure 132 (146X)................................................
145 135.
Overall mosaic of 5B3B2E (second face) (9.7X)................................................
146 136.
Area "A" in Figure 135 (146X)................................................
147 137.
Area "B" in Figure 135 (146X)................................................
147 138.
Engineering stress/strain curve for tensile specimen R20C54-4C............................ 148 139.
Typical carbide distribution in R20C54 (678X)................................................
149 140.
Typical microstructure in R20C54, corresponding to same area as Figure 87 (678X).149 12
A A R EVA 51-5046570-01 1
Introduction
1.1 Background
Diablo Canyon Power Plant Unit 1 (DCPP-1) is one of two pressurized water reactor plants operated by the Pacific Gas and Electric Company. Unit' 1 is an 1125 MWe plant that went into commercial operation in May 1985. DCPP-1 has four Westinghouse Model 51 recirculating steam generators'with 3388 U-tubes each. The tubing material is 7/8 inch OD mill annealed Alloy 600, with a nominal wall thickness of 0.050 inch. The tubes were initially roll expanded -into -the tubesheet several inches from the primary side. Before unit startup,.the tubes were expanded along the full tubesheet depth using the'WEXTEX ebxplosive process to eliminate the tube to tubesheet crevice. The'tubes are. supported along their length by drilled-hole carbon steel tube support plates (TSP).
During the scheduled 1R12 outage in February 2004, sections of 1 tube -
R20C54 - were removed from steam generator 11 to -meet the' three-cycle frequency requirement of EPRI Report No. 1006255. During inspection, this tube was found to have a field bobbin coil eddy current (EC) indication at the 1 st TSP (1 H) intersection. This indication was confirmed by rotating coil EC to be axially oriented OD stress corrosion cracking (ODSCC).
1.2 Examinations Performed Laboratory examinations of the pulled tubes were conducted by Framatome ANP, Inc. (FANP) and by BWX Technologies, Inc. (BWXT) under contract to FANP, in support of NRC GL 95-05 requirements for voltage-based alternate repair criteria (ARC) for axial ODSCC.
The primary objectives of the examinations were the following:
- To characterize tube degradation (i.e., morphology, size, and extent) for correlation with field NDE results and to verify that the. degradation morphology is consistent with the assumptions made in NRC GL 95-05.
- To determine the effect of degradation on the burst strength of the tubing and the leak rate under main 'steam line break (MSLB) conditions.
These examinations included receipt inspection and verification of identity, eddy current testing, dimensional measurements, leak rate and burst testing, visual and stereovisual inspections and photography, scanning electron microscopy (SEM) including energy dispersive spectroscopy (EDS),
fractography, metallography, and tensile testing.
Data from these examinations1 are summarized and discussed in this report.
'Destructive examination data included in this report is from the following document: Examinations of Diablo Canyon Unit I Steam Generator Tube Sections from R20C54, BWX Report No. 1140-031-04-12, August 2004.
13
A AR EVA 51-5046570-01 1.3 Quality Assurance All examinations were performed as Safety Related work in accordance with Framatome ANP QA Program -and Quality Management Manual 56-5015885-02.
This program meets the requirements of 10CFR50, Appendix B. A QA Data Package for this work will be maintained by FANP in accordance with applicable procedures.
14
A AR EVA 51-5046570-01 2
Tube Failure Analysis 2.1 Receipt Visual Inspection Sections of tube number R20C54 from Diablo Canyon SG 11 were received at the Framatome ANP (FANP) SERF-4 facility on Wednesday, May 5 2004. The tube sections removed and their relative elevation -in the steam generator are illustrated in Figure 1. Section (piece) numbers 3, 4, and 5, containing the IH and 2H TSP locations and the free span tubing between these locations were unpacked, inspected, and prepared for testing. Results of the receipt inspection are documented in Reference 1 and are summarized in Table 1.
Figure 2 illustrates the typical as-received appearance of tube number R20C54 at the 1H TSP intersection. As can be seen in the photograph, the location at which the support plate contacted the tube is clearly visible from the remaining' accumulation of deposits.
rNote the almost complete absence of scale on the OD. With the exception of the TSP locations, the OD of all sections of R20C54 inspected was free of the scale normally found on pulled tubes.' This is attributable to steam generator'chemical cleaning operations conducted prior to tube removal. *A small amount of deposit
'remains at the TSP locations; at the 2H TSP, the remaining deposit had the appearance of having been "packed", or compressed, in the tube to TSP crevice region.
In general, the OD of the tube was gun-metal grey in color, with axial patches and spots of copper colored oxide (Figure 2) present on all of the sections.
During the receipt inspection, an axial notch -50% TWN was placed on the OD at the bottom end of each tube section using a Dremel tool and-small cut-off wheel. In subsequent examinations, all field and laboratory axial positions are referenced from the bottom end of the tube sections and all angular orientations are referenced to the notch, with angles increasing in the clockwise (CW) direction looking at the bottom end of the tube.
2.2 Eddy Current Inspection Following receipt inspection and prior to leak rate testing, tube sections R20C54-3 and R20C54-5 were inspected with bobbin coil and 3-coil rotating pancake coil (RPC). These inspections used a'Zetec 0.720 inch diameter M/ULC bobbin -coil and a Zetec 0.720-inch diameter Delta' head 3-coil RPC containing a 0.115-inch diameter pancake coil, a +Point'coil, and a 0.080-inch diameter high frequency pancake coil. Zetec ZAC/EddyNet 11i Patch 1.11 software was used for data acquisition and Ili Patch 1.9 software was used for data analysis.
The Examination Technique Specification Sheets (ETSS's) in PG&E Procedure NDE ET-7 Rev. 4 were followed for all data acquisition and analysis'. Complete details of the examinations, including graphics, can be found in Reference 2.
15
A AR EVA 51-5046570-01 Results of the receipt eddy current inspection are summarized and compared with data from both the initial in-generator examination (pre tube pull),and the on-platform (post tube pull) examination in Tables 2 and 3. In Table 3, the angular orientation of the indication in degrees is included in the "Call" column as measured 'clockwise (CW) from the reference slit in the bottom of the tube section.
The following paragraphs discuss the results for each tube section inspected.
R20C54-3, 1 H The field bobbin coil inspection identified a 5.60 volt (V) DOS2 indication approximately in the middle of the 1 H TSP. The +Point coil identified three single axial indications (SAI) at this location, with the largest indication measured-at 4.OOV. Following tube pull, the bobbin voltage increased to 6.71V (on platform) and 6.83V (in lab). The rotating probe voltage increased to 4.61V (on platform) and 4.48V (in lab). These increases in voltage may have occurred as a result of ligament tearing between micro cracks-and/or a change'in the width of the crack following removal of the tube from the steam generator; i.e., the primary crack may have opened up slightly when no longer constrained by the TSP or deposits within the TSP. The largest SAI was estimated to be 88 to 91% through wall and positioned 190 from the reference notch. The two smaller SAl's were positioned 330° and 2920 from the reference notch:
R20C54-5, 2H A dent indication (DNT) was recorded with the bobbin coil during the in-generator, on platform, and lab inspections in approximately the middle of the 2H TSP; however, no degradation was noted with either the bobbinor rotating coils.
The dent voltage decreased following tube pull, which may reflect removal of the influence of the tube support plate on the dent signal.
Although no degradation was initially reported, 2 patches of intergranular corrosion approximately 1800 apart were visually -observed within the' 2H TSP region following burst testing (see Section 2.8 for details). The tube had burst within the patch of corrosion centered at' 30' from the reference notch. As a result, the eddy current data acquired prior to and following the tube pull was reviewed once again to determine if the intergranular corrosion was detectable.
A careful review of the bobbin coil data revealed no indication of degradation other than the dent indication that was reported initially.
Review of the rotating coil data revealed a small volumetric indication only detectable after the tube section had been removed from the steam generator.
The location of the volumetric indication was -450 clockwise from the reference notch. To provide an estimate of its depth, a phase curve was set using the ASME standard drill holes.
Only the data acquired in the lab included a 2 A "DOS" indication is defined as a distorted support plate signal with a possible OD indication.
16
LIA AR EVA 51-5046570-01 U
calibration using the ASME standard, so no depth is given in the table for the platform data.
Results of the data review are summarized in Table 4.
2.3 Leak Rate Testing Room temperature leak rate testing was performed per EPRI guidelines[3 on the two sections of tubing containing the TSP intersections.,-The test setup used the'-
Framatome ANP insitu pressure test system and consisted of a full length tool head locked into the bottom end of each sample as a' water supply probe and a full length tool head locked into the top end of each tube'as a vent and stopper probe.
Test pressures included 1750 psi (normal operating pressure corrected for temperature and gauge effects), 2250 psi (intermediate pressure), and 2750 psi (MSLB pressure corrected for gage -effects and for the effect of temperature on material properties). The tests were conducted with approximately 2 minute hold periods at each of these pressures. Results of the leak test are summarized in Table 5.
The test pressure and leak rate versus time (time in seconds) results for tube section R20C54-3 are shown in Figure 3. Tube section R20C54-5 (2H TSP) did not leak at any of the pressure differentials tested. Tube section R20C54-3 (IH ITSP) developed a small leak at the highest pressure tested..The maximum leak' rate recorded during the 5 minute hold period was -0.002:gpm.'
After-2
-minutes, the" leakage decreased first to -0.001 gpm and then to less than detectable (<0.001 gpm). Although deionized water-was -used in the tests'to t
minimize the potential for particles in the water, it's possible that particulates in the pulled tube test specimen may have deposited within the crack.
I jComplete details of the leak rate tests can be found in Reference 4.
Following leak rate testing, the tube sections were reexamined visually and Section R20C54-3 (1H TSP) was'subjected to-repeat eddy current inspection with the 3-coillrotating probe.' The'eddy current inspection results before and after leak rate testing for-this section are summarized in Table 6. -Line by line phase angle sizing comparisons for the field (in-generator-and on-plafform), the lab receipt (pre leak rate' test),- and -the post leak rate test -eddy: current inspections are shown in Figures 4 through 6 for the-3 single axial indications.
Note that the indicated'flaw lengths increased for the primary defects' following LI Jleak rate testing.
2.4 Furnace Oxidation t
Because only-the -IH intersection leaked and thus -may have experienced ligament tearing during the leak rate test, Section R20C54-3 (1H TSP) was placed in an atmospheric furnace and held at 900OF for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to heat tint/oxidize U
any torn ligaments. The objective was to allow any tearing that occurred during leak rate testing to be distinguished from tearing that would occur later during 17
A AR EVA 51-5046570-01 burst testing.
The time and minimum temperature required to oxidize the ligaments were selected based on'a qualification test program carried out in advance of the leak rate testing.151 Figure 7 is a photograph of tube no.,R20C54-3 at -190 rotation taken following the oxidation step. As expected, the magnetite scale took on a burnished color as a result of oxidation.
Note that at this magnification, the suspected ODSCC defect at the -19° orientation is visible.
2.5 Post Oxidation Inspections Low magnification photographs were taken at 450 intervals at the TSP regions on
-both tubes to document their overall condition following the leak rate testing and furnace oxidation. These photographs are provided in Figures 8 - 23.
The bottom end of each tube segment is always positioned to the left in these
,photographs.
A photo mosaic of the axial crack that was detected by eddy current testing at:-
-190 on 1H is presented in Figure 24. It was visible from -0.2 inches to -0.6 inches from the bottom of the TSP region (after burst testing, the actual length was determined to be 0.7 inches, beginning at the bottom of 'the TSP region).
Possible cracks were also visible near '285', extending from -0.3 inches to -0.4 inches from the bottom of the TSP, as shown in Figure 25. 'These may correspond to the eddy current indication (SAI #3) identified at 2920. :No visible cracks were found that could be attributed to the eddy current indication (SAI #2) at 3300.
No visible evidence of corrosion was found in the 2H TSP region.
2.6 Sectioning Diagrams Detailed sectioning diagrams for all of the tube sections examined are provided in Figures 26 - 31. The secondary' defect locations indicated by eddy current testing are shown in Figure 27.
In the following discussions of test results, reference will be made to specific tube sections as defined in these diagrams.
2.7 Burst Testing Sections containing the 1 H (R20C54-3B)'and 2H (R20C54-5B) TSP regions were subjected to burst testing at room' temperature in accordance 'with EPRI guidelines for leak and burst testing 6], along with a free span region from Section R20C54-4. In -addition, a control sample' of virgin tubing was tested for baseline purposes.' The burst tests were performed simulating free span'conditions with no supports enveloping the tube segments. Silicon plastic bladders were used in all the samples, and 0.006":thick brass shim was used at the 1 H defect location in accordance with the-EPRI guidelines. These guidelines also stipulate a pressurization rate of 20 - 500 psi/sec, as measured between -2,000 psi and
-6,000 psi (prior to'yield), or up'to the point of rupture in the case of the defect specimens. -During these tests, the pressurization rates ranged from 602 to 772 psi/second. The higher pressurization rate is not believed 'to have affected the 18
A AR EVA 51-5046570-01 test results, since previous guidelines 7 1 had stipulated a pressurization rate of 200 - 2000 psi/sec, and hence these higher pressurization rates are consistent with earlier test guidelines and results.
Burst test results are summarized in Table 7.
Dimensional measurements required by the EPRI guidelines are provided in Tables 8 - 11. All fish mouth:
burst openings were axially oriented. Specimen R20C54-3B, which' contained':
the 1H TSP, burst at 5,819 psi. Specimen R20C54-5B, which contained the 2H TSP, burst at 10,428 psi.
Specimen R20C544B, which was the free 'span section, burst at 11,695 psi. The tube control sample, from heat #754225, burst at 10,145 psi.
2.8 Macro Photography/Stereovisual Examinations of Post-burst Regions Following burst testing, visual inspections were performed at low magnification to characterize the burst ruptures and associated areas of interest.
Low magnification photographs were taken at 450 intervals in the TSP regions, and of
'the burst opening on the free span section of tubing. Photographs were taken of additional selected areas during the stereovisual examinations -of these' tube sections as described in the following paragraphs. The bottom end of each tube segment is always to the left in these photographs.
Macro photographs of this tube section in 450 intervals are provided in Figures-32
- 39, and a similar photograph centered over the fish mouth opening at 190 is provided in Figure 40.
Higher magnification photographs of the f counter clockwise (CCW) and clockwise (CW) burst rupture surfaces, showing the oxidized intergranular corrosion areas, are provided in Figures 41 and -42. The burst region was located at approximately 190, with' the bottommost extent 6of the oxidized defect region near the bottom of the TSP.
SEM fractography (Section 2.9) later revealed a total axial extent of -0.7 inches and a length'of -0.12 inches where the defect was 100% through wall.
A secondary crack was located at -3500, parallel to the burst rupture, which extended from -0.1 inches to -0.2 inches from the bottom -of the TSP. This can be seen in Figure 43. Additional secondary cracks were located at -355°,' also parallel to the burst rupture, and which extended from -0.5 inches to -0.7 inches from the bottom of the TSP. These can be seen in Figure 44.
R20C54-4B (Free Span)
The fish mouth rupture on (nondefect) free span specimen R20C544B occurred near 350°. A photograph of the burst rupture is provided in Figure 45.
As described in Section 2.9, SEM fractography verified that the' failure was completely ductile, with no IGSCC present.
Macro photographs of this tube section in 450 intervals are provided in Figures 46
- 53, and a similar photograph centered over the fish mouth opening at 300 is 19
A ARIEVA 51-5046570-01 provided in Figure 54.
Higher magnification photographs of the CCW and CW burst rupture surfaces are provided in Figures 55 through 58. This sample was not oxidized in the furnace since it did not leak during leak rate testing. The burst region was at approximately 30°, and was contained within an area of intergranular corrosion which extended from QO0 to 90°, as shown in' the schematic drawing in Figure 59. A separate area of intergranular corrosion, which is also shown in the schematic drawing in Figure 59, extended from -235° to -3050.
From the macro photographs, it is apparent that the intergranular corrosion extended above the 0.75-inch long TSP intersection in the region from' 0° to 900. This was later confirmed by SEM fractography (Section 2.9), which revealed a total preburst axial extent of corrosion of -0.795 inches along the burst rupture surface.
This observation suggests that a small sludge pile or accumulation of deposits may have been present on top of the 2H TSP in this location from 00 to 90° during some period in time.
The intergranular corrosion in the 2350 to 3050 region appears to be contained within the 0.75-inch long TSP contact region.
2.9 SEM Fractography Standard internal distance calibrations on the SEM are routinely performed at 1OOX. To ensure that these calibrations were still valid at the 50X range used to obtain the photo mosaics, a section of metallic ruler that could be placed in the SEM was photographed adjacent to a calibrated stage micrometer used on the metallograph.
Comparisons between the 'calibrated stage micrometer,, the section of ruler, and the internal SEM calibrations, provided traceability and indicated that the measurements were accurate to +/-1% (+/-0.0005 inches for a 0.050 inch nominal wall thickness).
R20C54-3B2 (1 H TSP)
Low magnification photo mosaics of the counterclockwise (CCW) fracture surface from R20C54-3B2 are provided in Figure 60 (rotated 180° to keep axial bottom to the left in this report). The secondary electron (SE) image provides the best topographical information, whereas' the backscattered electron (BSE) image provides information on material density (less dense materials, such as oxides and plastic bladder material, show up darker).
Higher magnification photographs typifying the areas at the bottom, center, and top of the fracture surface are provided in Figures 61 - 67 (rotated 1800 to keep the axial bottom to the left throughout this report).
The actual depth measurements of intergranular corrosion were obtained from photographs such as these.
This data is tabulated in Table 12.
The starting point for these measurements was' at the bottom edge of the IGSCC, and axial lengths were measured at the mid-wall of the tubing. 'Based upon these measurements, the total axial extent of the intergranular corrosion was 0.7 inches, with 100%
through wall cracking (>0.052 inches) extending over an axial extent of 0.12 inches. A plot of the depth of intergranular corrosion is provided in Figure 68a.
No oxidized ductile tear regions, which would have indicated tearing during the 20
A AR EVA 51-5046570-01 leak test, were identified. Comparison of the measured crack depth profile vs.
the post-leak rate test RPC data is shown in Figure 68b. The measured crack depths were normalized using a nominal wall thickness of 0.052 inches.
R20054-5B3 (2H TSP)
Low magnification photo mosaics of the clockwise (CW) fracture surface from R20C54-5B3 are provided in Figure 69.
Higher magnification photographs typifying the areas at the bottom, center, and top of the fracture surface are provided in Figures 70 - 75. The actual depth measurements of intergranular Corrosion along the fracture surface were obtained from similar photographs,'and this data is tabulated in Table 13. The starting point for these measurements was at the bottom edge of the' corrosion, and axial lengths were measured at the mid-wall of the tubing.
Based upon
'these measurements, the total axial extent of the intergranular corrosion was, 0.86 inches, and the maximum depth was 0.0239 inches (46% TW based on a 0.052-inch nominal wall thickness). Since the non-corroded portion' of the tube wall experienced significant thinning and axial strainr prior to burst, the axial extent of corrosion as measured along the'fracture face was greater than the pre-burst length. The measured axial positions were adjusted in Reference 8 to account for this effect. The adjusted cumulative lengths are tabulated in Table 13 and the depth of the intergranular corrosion is plotted against these values in Figure 76 to illustrate the actual corrosion profile. As can be seen in 'the table and in Figure 76, the adjusted overall extent of intergranular corrosion is 0.795 inches, approximately 0.045 inches beyond the uppermost edge of the'2H TSP.
The location of the deepest'corrosion is between 0.679 and 0.735 inches from the bottom edge of the 2H TSP and therefore contained within the 2H TSP thickness.
R20C54-4B (Free span)
Secondary electron images showing the lack of corrosion in the free span burst sample are provided in Figures 77 and 78.
2.10 EDSIWDS Analyses R20C54-5B3 (2H TSP Region)
Areas on the burst rupture surface of R20C54-5B3 (2H TSP) were examined using energy dispersive spectroscopy (EDS) -to look for the-presence of detrimental elements that may have contributed to the intergranular corrosion.
This sample was selected since it had not been subjected to ihigh-temperature oxidation in the furnace (the 1 H TSP region was oxidized in this manner). Sulfur, silica, and potassium were detected on the fracture surface as shown in the EDS spectrum in Figure 79. The presence of sulfur was confirmed and trace levels of magnesium and'lead were also indicated by wavelength dispersive spectroscopy (WDS) analysis.
21
A AR EVA 51-5046570-01 Copper Colored Deposits in Free span Areas Copper colored deposits were visible on some areas of the tubing OD in the free span areas.
A typical example is shown in Figure 80.
EDS analysis was performed to identify this material, and as shown in Figure 81, it was composed of aluminum, zinc, and oxygen. Neither copper metal nor copper oxides were detected.
2.11 Defect Metallography Transverse Metallographic Cross-Sections Transverse metallographic cross-sections were prepared through two areas of
-the 1H TSP, corresponding to the axial locations of the secondary eddy-current' indications (SAI #2 and SAI #3 in Figure 27). The first of these -(SAI-#3) was at the approximate axial centerline of the TSP at 2920, and the second (SAI #2) was approximately 0.1 inches above the axial centerline of the TSP at 330Q.O These transverse metallographic cross-sections provided information on the extent and depth of IGSCC around the circumference of the tube away-from the actual burst region. Serial grinding was not performed on these samples, so the maximum depth of IGSCC observed does not necessarily reflect the actual maximum depth indicated by eddy current testing.
R20C54-3B2B1 (1 H TSP centerline)
Figure 82 is a polished cross-section showing a 53% through wall secondary crack at 2980 that corresponds to the approximate location of eddy current indication SAI #3 (at 2920). The intergranular nature of the cracking is apparent in the etched photomicrograph of the same area in Figure 83. A number of other axial intergranular penetrations were noted around the circumfere nce of the tube at this location, and these are tabulated in Table 18.
R20C54-3B2B2 (1 H TSP centerline + 0.1 inch)
Figure 84 is a polished cross-section showing a 40% through wall secondary_
crack at 330° that corresponds to the approximate-location of a secondary eddy current indication at 3300 (SAI #2). The intergranular nature of the cracking is apparent' in the etched photomicrograph of the same area in Figure 85. A number of other axial intergranular penetrations were noted around the circumference of the tube at this location, and these are tabulated in Table 19. It should be noted that several relatively deep cracks (47% to 65% TW) were located on both sides of the primary crack-(burst rupture) at 19°.
Radial Grinding Serial grinding was performed normal to the tube surface (radially) on mounted specimens taken from the 2H TSP region to better characterize the two regions of intergranular corrosion (see: Figures 31 and 59 for locations).
Each metallographic sample was flattened in a vise prior to mounting so that the ground surface would be parallel to the flattened tube-surface. Following each incremental grind, the specimens were polished and photographed using the 22
A AR EVA 51-5046570-01 backscattered electron imaging mode on the scanning electron microscope.
Serial grinding continued in -0.005 inch increments until all evidence of intergranular corrosion was no longer present. The depth of each polished face from the OD surface is provided in Table 14.
These areas of corrosion exhibited grid-like patterns of OD axial and circumferential cracks. By virtue of itsi appearance, the industry has dubbed this, type of degradation as "cellular corrosion". 'Cellular corrosion is generally shallow and transitions to predominantly axial cracks as the cracking progresses inward from the OD. As can be seen in the photographs discussed below, this 'behavior was observed during the radial grinding.
R20C54-5B3BB1 (2H TSP)
Sample 5B3B1 consisted of the region immediately clockwise from the burst rupture, extending from approximately 300 to 450. SEM fractography previously' characterized the burst rupture surface along the edge of-this. sample.
Intergranular corrosion was present through the fourth grind (0.022" from the OD), but none was present on the polished face after the fifth grind (0.028").
This is consistent with the maximum depth of 0.024" measured from SEM fractography on the burst rupture surface.
Overall photo mosaics of -each polished face, along with higher magnification photographs showing details of the intergranular corrosion, are provided in Figures 86 through 99.
R20C54-5B3B2A (2H TSP)
Sample 5B3B2A extended circumferentially from approximately 450 to 1200.- A corroded area was present near the upper portion of the 2H TSP (-0.6" to -0.9" from the bottom of the TSP), in the area from -45° to 800. A second corroded area was present in the bottom portion of the TSP (0.0" to -0.5" from the bottom-of the TSP), in the area from -450 to -90°. These two areas were photographed separately. Intergranular corrosion was present through -the fifth grind (0.028" from the OD), but was absent on the sixth polished face (0.036"). Overall photo mosaics of each face, along with higher magnification photographs showing details of'the intergranular corrosion, are provided in Figures 100 through'119.
For orientation purposes, a notch was placed on the bottom end at _900.'
R20C54-5B3B2C (2H TSP)
Sample 5B3B2C extended circumferentially from approximately 2250 to 3150. A corroded area extended over the region from approximately 2350 to 3050 in the upper half of the TSP. Intergranular corrosion was present through the fourth grind (0.022" from the OD), but was absent on the fifth polished face (0.027").
Overall photo mosaics of each face, along with higher magnification photographs showing details of the intergranular -corrosion, are -provided -in Figures 120 through 131. For orientation purposes, a notch was placed on the bottom end at
-2700.
23
A AR EVA 51-5046570-01 R20C54-5B3B2E (2H TSP)
Sample 5B3B2E consisted of the region immediately counterclockwise from the burst rupture, extending circumferentially from approximately 3400 to 300.
Intergranular corrosion was present through the second grind (0.018" 'from the OD surface), but was absent on the third polished face (0.026"). Overall photo mosaics of each face, along with higher magnification photographs'showing details of the intergranular corrosion, are provided in Figures' 132 through 137.
For orientation purposes, a notch was -placed on the bottom end at -0°.
2.12 Material Properties Tensile Testing One sample from a free span region was tensile tested at 700F, and the results are provided in Table 15. The engineering stress/strain curve is provided in Figure -138.
The nominal tubing OD was 0.873 inches and the nominal'wall thickness was 0.0524 inches.
Bulk Chemistrv A section of tubing was decontaminated for bulk chemical analysis. The analysis results presented in Table 16 are consistent with Alloy 600 material.
Microstructure A longitudinal metallographic sample was prepared from the free span region. A dual etch procedure using phosphoric and nital acid solutions was used to characterize the carbide distribution and 0'grain microstructure. '-The results are shown in Figures 139 and 140.
The carbide distributionr along the grain boundaries was very light, and intragranular matrix carbides were also present.
Hilliard Circular intercept measurements indicated an ASTM grain size of 8.5 (16.4 prm average grain intercept distance).
Summary The material properties discussed above are summarized and compared with the material test report values and 'with the ASME specification for SB-163 (Alloy 600) in Table 17. As can be seen in the table,' the material properties for tube no.
R20C54 are in agreement with both the material test report and the ASME specification.
24
A AR EEVA 51-5046570-01 3
Summary of Laboratory Examinations The following summary observations were made based on the results of the laboratory examinations documented in this report:
- Laboratory eddy current inspection of the pulled tube sections confirmed the presence of 3 defect'indications (SAI) at the IH TSP location and a dent indication (DNT) in approximately the middle of the 2H TSP location.
- The section of tubing from the 1 H TSP location developed a small leak when subjected to a pressure differential of 2750 psi (MSLB pressure corrected for gauge effects and for the effect of temperature on material properties). The maximum room temperature leak rate recorded was 0.002 gpm.
- Burst pressure for the section of tubing from the 1H TSP location was 5,819 psi. The location of the burst was at approximately 190, corresponding to the location of the largest eddy current defect indication. 'SEM fractography revealed a total axial extent of IGSCC of 0.7 inches, -0.12 inches of which was through wall. SEM fractography also confirmed that ductile" tearing of ligaments had not occurred during the preceding leak rate test.
- Transverse metallography of the post-burst 1H TSP section revealed a 40%
TW crack at 330° (-0.1 inches above the center of the TSP), in the approximate area of the second eddy current indication (SAI #2). A second transverse metallographic section near the centerline of the 1 H TSP revealed a 53% TW indication at 2980, in the approximate area of the third eddy current indication (SAI #3) reported at 2920.
- No defects were identified in the 2H TSP crevice during field eddy current testing; however, the tube section containing the crevice region burst at 10,428 psi at -300 in an area of intergranular corrosion. SEM fractography confirmed a preburst axial extent of intergranular corrosion of 0.795 inches, with a maximum depth of 0.0239 inches (46% TVW). The maximum depth of corrosion was located within the TSP thickness toward -the upper edge; however, the overall extent of co'rrosion suggests that a small sludge pile may have existed in this area (O° to 90°) during some period in time, creating the conditions for an aggressive environment to develop' outside -of the'tube-TSP intersection.
- A second patch of intergranular corrosion was also present in the upper half of the 2H TSP crevice from -235° to 3050. A review of the eddy current data records confirmed that neither area of degradation was detected by either the bobbin or rotating eddy current probes during the field inspection. A srmall, single volumetric indication was found in the post-pull'rotating coil data at
.450.
- Radial grinding demonstrated that the intergranular corrosion 'within the 2H TSP interface region became predominantly axially oriented as the corrosion progressed inward from the OD.
The morphology of the intergranular 25
Li A
AR EVA 51-5046570-01 corrosion and its behavior as it progressed inward from the OD is typical of cellular corrosion.
L EDSNVDS analysis revealed the presence of sulfur on the 2H burst rupture l
surface.
L Material properties for tube no. R20C54 were in agreement with the material test report values and with the ASME SB-163 specification.
L Ii L
L L
L L
26
A AREVA 51-5046570-01 4
Conclusions The laboratory examinations confirmed that axial OD intergranular stress corrosion cracking (IGSCC) was present in the 1H TSP region. The total axial extent and through wall portion of the primary defect were 0.70 and 0.12 inches, respectively.
In addition, two smaller IGSCC cracks were present at other circumferential locations. The burst pressure for this section was 5,819 psi. The corresponding free span region without defects burst at 11,695 psi.
The burst pressure for the 2H TSP section'was 10,428 psi. Post-burst inspection revealed two patches of intergranular corrosion that had not been detected during eddy current inspection prior to tube pull. The maximum depth-of the corrosion in the burst region was determined to be less than 46% through wall. A detailed review of the eddy current data records confirmed that corrosion-was not detected by either the bobbin or rotating eddy current probes during the in-generator inspection. A small, single volumetric indication (SVI) was found in the post-pull rotating coil data during the same review of the data records.
Radial grinding through these patches of intergranular corrosion showed that the orientation of the intergranular penetrations became predominantly axial as the corrosion progressed inward, which is typical behavior for 'cellular corrosion".
SEM/EDSNVDS analysis revealed the presence of sulfur on the 2H burst rupture" surface. Sulfur is known to be detrimental to Alloy 600 and has been previously implicated in intergranular corrosions9].
27
A AR EVA 51-5046570-01 5
References
- 1. Quality Control Inspection Report No. 6033666, 6/30/2004.
- 2. FANP Document No. 51-5044913-00, "Eddy Current Tube Pull Examination for PG&E Diablo Canyon Unit 1 -April 2004," 6/14/2004.
- 3. Steam Generator InSitu Pressure Test Guidelines: Revision 2, EPRI TR-10007904, August 2003.
- 4. FANP Document No. 51-5044611-00, "Diablo Canyon Unit 1 Tube Pull Leak Rate Test Results," 5/11/2004.
- 5. FANP Document No. 51-5025213-00, "7/8" OD RSG Tube (Alloy 600) Oxidation Test Results," 3/12/2003.
- 6. Steam Generator Tubing Burst Testing and Leak Rate Testing Guidelines, EPRI Report No. 1006783, Final Report, December 2002.
- 7. Guidelines for PWR Steam Generator Tubing Specification and Repair, Volume.
4, Revision 1, EPRI TR-016743-V4Rl, December 1997.
- 8. FANP Document No. 32-5050059-00, "Diablo Canyon 1 SG Tube Sample R20C54-5B3B Burst Fractography," 8/25/2004.
- 9. PWR Secondary Water Chemistry Guidelines - Revision 5, EPRI TR-1 02135-R5, Final Report, May 2000.
28
A AR EVA 51-5046570-01 Table 1. Diablo Canyon Unit I SG 11 Tube Receipt Inspection Summary As-Distance to receved On-site landmark from SapeLength bottom of Landmark comments Identification Length (in t
sco (inches) (innes)huesecin R20C54-3 26 25 7 15 Y2 Bottom of 1H OD scale is absent due to TSP on-site chemical cleaning; little smearable contamination present.
Some deposit buildup remains at I H TSP location.
Patches of copper colored '
oxide observed below TSP location, small spots of copper colored oxide observed above TSP.
24 1/2 Circumferential Field applied saw cut.
saw cut Partial through wall axial cut
-0.4 inches long placed inch above tube section;':
bottom with a Dremel tool to serve as 00 reference point for RPC inspection.
R20C54-4 28 %
28 /
26 %
Circumferential OD surface is free'of scale, (free span) saw cut with spots of copper colored oxide randomly distributed over lower half of section. '
00 reference point for RPC inspection transferred to Section 4 from Section 3 R20C54-5 36 36 11 %
Bottom of 02H OD scale absent; regions of TSP "compressed" magnetite present on OD within TSP location from 0 to 1800. No visible signs of denting.
Brown deposit buildup present on OD at bottom of TSP crevice location. Axial bands of copper colored oxide observed below TSP from 90 to 1200 and above TSP at 300 to 3400.
35 Circumferential 00 reference point for RPC saw cut inspection transferred to Section 5 from Section 4.
29
A AREVA 51-5046570-01 Table 2. Bobbin Eddy Current Inspection Results Summary Tube Location in Pre Tube Pull Post Tube Pull In Lab Section No.
SG Call Volts Phase Call Volts Phase Call Volts Phase R20C54-3 1H + 0.13" DOS 5.60 69 DOS 6.71 69 DOS 6.83 68 R20C54-5 2H + 0.11n DNT 3.27 175 DNT Ill 168 Table 3. Rotating Coil Eddy Current Inspection Summary Pre Tube Pull Post Tube Pre Leak Rate Test Section Data Location (In-Generator)
(On Platform)
(In Lab)
Neto.
Source in SG(OPlfom Call Volts Phase Volts Phase O
ati Volts Phase
_____________________O rie n tatio n_________
FDMSa 1 H+0.03 SAI 4.00 610 Ref. 2 1H+0.04 SAI#1 3.99 610 4.61 530 SAI/90%/19° 4.48 540 R20C54-FDMS I H+0.00 SAI 0.27 960 3
Ref. 2 1 H+0.04 SAI#2 0.27 940 0.23 1020 SAI/73%/3300 0.20 790 FDMS 1 H+0.07 SAI 0.08 1230 Ref. 2 1H+0.11 SAI#3 0.11 870 0.10 1250 SAI/68%/292 0 0.13 850 R20C54-FDMS 2H NDD N/A N/A 5
Ref. 2 2H NDD N/A N/A N/A N/A NDD N/A N/A a Framatome ANP Data Management System Table 4. Review of Rotating Coil Eddy Current Data for Section R20C54-5 Acquired prior to and following Tube Pull.
Tube No.
Location j
EC Call Volts Phase Max Depth Before Tube Pull 2H NDD N/A N/A N/A After Tube Pull R20C54-5 (2H)
SVI 0.18 1120 N/A Isn Lab, before Pressure esin R20C54-5 (2H)
SVI 0.15 1100 32% TW 30
A AR EVA 51-5046570-01 Table 5. Summary of Leak Rate Tests Tube Sample l Pressure Hold Hold Time Maximum Leak Avg. Pressurization No.
l Points, psi minutes Rate, gpm Rate, psifsec 1750 2
0.0000 20 R20C54-3B (IH) 2250 2
0.0000 6
2750 5
0.0020 4
1750 2
0.0000 19 R20C54-5B (2H) 2250 2
0.0000 12 2750 2
0.0000 14 Table 6. Rotating Coil Eddy Current Inspection Pre and Post Leak Comparisons Tube Sample Location in SG [
Pre Leak Test (In Lab)
Post Leak Test (In Lab) -
No.
Call Volts Phase l Call Volts Phase SAl SAI 1H + 0.04" (#1) 90% TW 4.48 540 92% T1 4.93 530
@190
@190 R20C54-3B (IH)
IH + 0.04' (#2)
SAl 0.20 790 77% 3W 0.33 770 SAIT
@3300 T
1 H + 0.11' (#3) 68% lW 0.13 85 67%
W 0.21 880 68 T W 0.3950@
2 2 Table 7. Room Temperature Burst Tests Sample Length Pressurization Rate Burst Pressure Tube Sample No.
Inhe slec:
si
_Inches Psilsecps Control tube 11.9 630 10,145 R20C54-3B (1H) 11.9 607
-5,819 R20C54-4B (free span) 12.1 620 11,695 R20C54-5B (2H) 12.1 772 10,428 31
A AREEVA 51-5046570-01 Table 8. Burst Test Dimensional Measurements - Control Specimen I Sample: Control Sample DefectAngle:
NA INITIAL LENGTH 11 15/16" Instrument= Ruler Calibration Due=
NA INITIAL DIAMETERS:
Bottom End, 00or Defect 0.877 Bottom end, ditto+900 0.876 Instrument = BW 1-0000-3549 Center, 00or Defect 0.876 Center, ditto+900 0.877 Calibration Due: 9/18/04 Top End, 00or Defect 0.877 Top end, ditto+900 0.876 INITIAL WALL THICKNESSES:
Bottom End, 00or Defect 0.05180 Bottom end, ditto+90° 0.05170 Instrument= BW 1006009 Bottom end, ditto+1800 0.05220 Bottom end, ditto+2700 0.05220 Calibration Due: 4/13/05 Top End, 00or Defect 0.05165 Top end, ditto+900 0.05160 Top end, ditto+1 800 0.05210 Top end, ditto+2700 0.05225 POSTTEST DIAMETERS:
Remote, aligned w/Rupture 1.061 Remote, difto+900 1.057 Instrument = BW 1-0000-3549 Burst (C/L-1"), at rupture 1.036 Burst (C/L-1"), ditto+900 1.078 Calibration Due: 9/18/04 l
Burst, at rupture 1.280
@ Burst, ditto+900 1.125 Burst (C/L+ 1"), at rupture 1.043 Burst (C/L+ 1"), ditto+900 1.077 BURST DIMENSIONS Burst Rupture Length 1.959 Burst Maximum Width 0.328 Distance From Bottom of Tube to Bottom of Burst Region 3.390 Burst Position, angle 900 32
A AR EVA 51-5046570-01 Table 9. Burst Test Dimensional Measurements - R20C54-3B (1H)
Defect Angle: 190 I
INITIAL LENGTH 11 15/16" Instrument = Ruler Calibration Due= NA INITIAL DIAMETERS:
Bottom End, 00or Defect 0.873 Bottom end, ditto+900 0.872 Instrument =
BW 1-0000-3549 Center, 00or Defect 0.875 Center, ditto+900 0.875 Calibration Due: 9/18/04 Top End, 00or Defect 0.872 Top end, ditto+900 0.872 l
INITIAL WALL THICKNESSES:
l Bottom End, 00or Defect 0.05180 Bottom end, ditto+900 0.05280 Instrument =
BW 1006009 Bottom end, ditto+1800 0.05290 Bottom end, ditto+2700 0.05230 Calibration Due: 4/13/05 Top End, 00or Defect 0.05185 Top end, ditto+900 0.05265 Top end, ditto+1 800 0.05310 Top end, ditto+2700 0.05200 POSTTEST DIAMETERS:
l Remote, aligned w/Rupture 0.873 Remote, ditto+900 0.873 Instrument BW 1-0000-3549 Burst (C/L - 1"), at rupture 0.870 Burst (C/L-1"), ditto+900 0.877 Calibration Due:
9/18104
@ Burst, at rupture 1.005
@ Burst, ditto+900 0.889 Burst (CIL+ 1"), at rupture 0.870 Burst (C/L+ 1"), ditto+900 0.876 BURST DIMENSIONS Burst Rupture Length 1.045 Burst Maximum Width 0.244 Distance From Bottom of Tube to Bottom of Burst Region 5.531 Burst Position, angle 190 33
A AREVA 51-5046570-01 Table 10. Burst Test Dimensional Measurements - R20C54-4B (Free Span)
LSample: R20C54-4B (Free span)
I Defect Angle:
NA I
INITIAL LENGTH 12 1/16" Instrument= Tape Calibration Due= NA' INITIAL DIAMETERS:
Bottom End, 00or Defect 0.873 Bottom end,'ditto+900 0.873 Instrument =
BW 1-0000-3549 Center, 00or Defect 0.872 Center, ditto+900 0.872 Calibration Due: 9/18104 Top End, 00or Defect 0.873 Top end, ditto+900 0.873 INITIAL WALL THICKNESSES:
Bottom End, 00or Defect 0.05130 Bottom end, ditto+900 0.05330 Instrument =
BW 1006009 Bottom end, ditto+1800 0.05360 Bottom end, ditto+2700 0.05235 Calibration Due: 4/13/05 Top End,O00or Defect 0.05160 Top end, ditto+900 0.05210 Top end, ditto+1800 0.05355 Top end, ditto+2700 0.05260 l
POSTTEST DIAMETERS:
l Remote, aligned w/Rupture 1.017 Remote, ditto+900 1.015 Instrument = BW 1-0000-3549 Burst (C/L-1"), at rupture 1.019 Burst (C/L-1"), ditto+900 1.052 Calibration Due: 9118/04
@ Burst, at rupture 1.246
@ Burst, ditto+900 1.095 Burst (CIL+ 1"), at rupture 1.015 Burst (C/L+ 1"), ditto+900 1.057 BURST DIMENSIONS Burst Rupture Length 1.941 Burst Maximum Width 0.390 Instrument BW 1-0000-3164 Distance From Bottom of Tube to Bottom of Burst Region 6.489 Calibration Due: 4/13/05 Burst Position, angle 3500
/
34
A AR EVA 51-5046570-01 Table 11. Burst Test Dimensional Measurements - R20C54-5B (2H) l Sample: R20C54-5B (2H1TSP)
I DefectAngle: NA INITIAL LENGTH 12 1/16" Instrument=
Tape Calibration Due= NA INITIAL DIAMETERS:
Bottom End, 00or Defect 0.873 Bottom end, ditto+900 0.872 Instrument =
BW 1-0000-3549 Center, 00or Defect 0.879 Center,ditto+900 0.880 Calibration Due: 9/18/04 Top End, 00or Defect 0.872 Top end, ditto+900 0.873
__l INITIAL WALL THICKNESSES:
Bottom End, 0°or Defect 0.05180 Bottom end, ditto+900 0.05305 Instrument =
BW 1006009 Bottom end, ditto+1800 0.05290 Bottom end, ditto+2700 0.05180 Calibration Due:
4/13/05 Top End, 00or Defect 0.05145 Top end, ditto+900 0.05280 Top end, ditto+1800 0.05360 Top end, ditto+2700 0.05200 POSTTEST DIAMETERS:
Remote, aligned w/Rupture 0.926 Remote, ditto+900 0.925 Instrument= BW 1-0000-3549 Burst (C/L - 1"), at rupture 0.913 Burst (C/L-1"), ditto+900 0.941 Calibration Due:
9/18/04
@ Burst, at rupture 1.160
@ Burst, ditto+900 0.964 Burst (C/L+ 1"), at rupture 0.911 Burst (C/L+ 1"), ditto+900 0.940 BURST DIMENSIONS Burst Rupture Length 1.475 Burst Maximum Width 0.383 Distance From Bottom of Tube to Bottom of Burst Region 5.402 Burst Position, angle 30° 35
A AR EEVA 51-5046570-01 Table 12. Defect Burst Specimen Fractography Measurements R20C54-3B2 (IH TSP)
Point 0
1 2
3 4
5 6
7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Incremental Length Segment (")
0.0000 0.0231 0.0418 0.0198 0.0205 0.0215 0.0182 0.0388 0.0027 0.0314 0.0171 0.0244 0.0154 0.0133 0.0457 0.0225 0.0529 0.0390 0.0070 0.0280 0.0208 0.0150 0.0049 0.0082 0.0150 0.0038 0.0356 0.0297 0.0086 0.0242 0.0235 0.0045 0.0048 0.0066 0.0053 0.0068 Cumulative Length (")
0.0000 0.0231 0.0649 0.0847 0.1052 0.1267 0.1449 0.1837 0.1865 0.2178 0.2349 0.2593 0.2746 0.2879 0.3337 0.3562 0.4091 0.4481 0.4551 0.4830 0.5039 0.5188 0.5237 0.5320 0.5470 0.5508 0.5864 0.6160 0.6247 0.6489 0.6724 0.6769 0.6818 0.6883 0.6936 0.7005 Depth IGSCC (")
0.0000 0.0130 0.0116 0.0217 0.0213 0.0274 0.0235 0.0290 0.0381 0.0388 0.0347 0.0440 0.0469 0.0521 0.0522 0.0522 0.0521 0.0508 0.0495 0.0363 0.0258 0.0150 0.0206 0.0131 0.0039 0.0080 0.0133 0.0085 0.0087 0.0000 0.0000 0.0039 0.0000 0.0000 0.0038 0.0000 Note: Starting reference point was at the axial bottom of the crack 36
A AREEVA 51-5046570-01 Table 13. Defect Burst Specimen Fractography Measurements R20C54-5B3B (2H TSP)
Point 0
1 2
3 4
5 6
7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 39A 40 41 42 43 Incremental Length Segment, in.
0.0000 0.0119 0.0109 0.0183 0.0081 0.0214 0.0174 0.0095 0.0148 0.0130 0.0093 0.0160 0.0163 0.0042 0.0081 0.0128 0.0149 0.0141 0.0093 0.0129 0.0184 0.0234 0.0130 0.0147 0.0367 0.0091 0.0359 0.0312 0.0188 0.0394 0.0232 0.0137 0.0360 0.0625 0.0452 0.0182 0.0210 0.0291 0.0034 0.0366 0.0060 0.0181 0.0132 0.0293 0.0221 Cumulative Length, in.
0.0000 0.0119 0.0228 0.0410 0.0492 0.0706 0.0879 0.0975 0.1122 0.1252 0.1346 0.1506 0.1669 0.1711 0.1792 0.1920 0.2069 0.2210 0.2303 0.2432 0.2616 0.2850 0.2981 0.3128 0.3495 0.3586 0.3944 0.4257 0.4445 0.4839 0.5071 0.5208 0.5567 0.6192 0.6645 0.6827 0.7037 0.7328 0.7362 0.7728 0.7788 0.7969 0.8102 0.8395 0.8616 Adjusted Depth Length, in.
IGSCC, in.
0.0000 0.0029 0.0110 0.0100 0.0210 0.0054 0.0379 0.0185 0.0454 0.0165 0.0651 0.0173 0.0811 0.0114 0.0899 0.0056 0.1035 0.0101 0.1155 0.0048 0.1241 0.0103 0.1389 0.0174 0.1540 0.0163 0.1579 0.0102 0.1653 0.0124 0.1771 0.0064 0.1909 0.0084 0.2039 0.0154 0.2125 0.0140 0.2244 0.0046 0.2414 0.0106 0.2630 0.0047 0.2750 0.0116 0.2886 0.0159 0.3224 0.0141 0.3308 0.0166 0.3639 0.0128 0.3927 0.0147 0.4101 0.0119 0.4465 0.0142 0.4679 0.0191 0.4805 0.0153 0.5137 0.0116 0.5714 0.0189 0.6131 0.0173 0.6299 0.0136 0.6493 0.0154 0.6761 0.0101 0.6793 0.0234 0.7131 0.0226 0.7186 0.0239 0.7353 0.0200 0.7475 0.0086 0.7746 0.0045 0.7949 0.0000 37
A ARE VA 51-5046570-01 Table 14. Depth (in inches) of Radial Grinds in the 2H TSP Specimens Metallographic Sample 5B3BBI l
5B3B2A 5B3B2C l
5B3B2E 1 st Face 0.005 0.005 0.006 0.011 2nd Face 0.011 0.011 0.011 0.018 3rd Face 0.017 0.017 0.015 0.026 (no corrosion) 4th Face 0.022 0.022 0.022 5 th Face 0.028 0.027 (no corro (no corro 6th Face0.036 6th Face
~~~~(no corrosion) _______________
Table 15. Tensile Test Results Property R20C54-4C Yield Strength (psi) 53,028 Tensile Strength (psi) 105,643 Total Elongation (%)
39.44 Reduction in Area (%)
37.8 Table 16. Bulk Chemistry Analysis Sample R20C54-4A Nominal Alloy 600 Element (wt. %)
(wt. %)
Ni Balance (75) 72 min (Ni + Co)
Cr 15.5 14-17 Fe 8.29 6-10 Al 0.077 C
0.021 0.15 max Co 0.047 Cu 0.16 0.5 max Mn 0.19 1.0 max P
0.009 Si 0.33 0.5 max S
0.003 0.015 max Ti 0.17 38
A AR EVA 51-5046570-01 Table 17. Summary Material Properties for Tube No. R20C54 Mill Test ASMVE SB-I163 Property R20C5 Report( 2)
Specifications3 Heat Number 7777 7777 Yield Strength, psi 53,028 49,000 Ultimate Tensile Strength, 105,643 106,000 psi10641000 Total Elongation, %
39.44 40 Reduction in Area, %
37.8 Not available ASTM Grain Size 8.5 Rockwell Hardness, RB Not 85 determined Carbide Distribution (Note 1)
Composition, wt%
Al 0.077 0.04 C
0.021 0.04 0.15 max Co 0.047 0.04 Added to Ni Cr 15.50 15.71 14.0- 17.0 Cu 0.16 0.21 0.5 max Fe 8.29 8.22 6.0 - 10.0 Mn 0.19 0.23 1.0 max Ni 75.0 75.17 72.0 min (+Co)
P 0.009 S
0.003 0.007 0.015 max Si 0.33 0.40 0.5 max Ti 0.17 0.33 Table 2-2 Notes:
(1) Carbides were primarily intragranular.
(2) Memo, David Beals to Joe Crockett dated April 17, 2004, 'Tube Pull SG 11 R20C54 (3) ASME Metals handbook Vol. 1 10th Edition, Materials Park, OH, March 1990.
39
A ARIEVA 51-5046570-01 Table 18. Depth of IGSCC near Axial Centerline of I H TSP (From Transverse Metallographic Sample R20C54-3B2B1)
Angular Orientation '
Depth degrees inWches
%TW 2
34 0.0204 39 40 0.0131 25 51 0.0079 15 52 0.0057 11 56 0.0077 15 59 0.0157 30 60 0.0062 12 62 0.0140 27 190 0.0176 34 238 0.0168 32 242' 0.0194 37 298 3 0.0277 53 316 0.0239 46 321 0.0182 35 328 0.0271 52 332 0.0257 49 340 0.0258 50 349 0.0223 43 352 0.0154 30 Notes:
1.
2.
3.
Angular orientations are relative and approximate.
% TW is based on measured 0.052-inch nominal wall thickness.
2980 corresponds to approximate location of SAI #3 (292°)
40
A ARE VA 51-5046570-01 Table 19. Depth of IGSCC At -0.1 inch above Axial Centerline of IH TSP (From Transverse Metallographic Sample R20C54-3B2B2)
Angular Orientation '
Depth Degrees inches
%TW 2 15 0.0243 47 18 0.0306 59 20 0.0339 65 220 0.0157 30 230 0.0154 30 250 0.0137 26 258 0.0215 41 262 0.0256 49 280 0.0215 41 330 3 0.0207 40 Notes:
1.
2.
3.
Angular orientations are relative and approximate.
% TW is based on measured 0.052-inch nominal wall thickness.
330° corresponds to approximate location of SAI #2.
41
A AR EVA 51-5046570-01 Diablo Canyon Unit 1 SG 1-1 Tube Sample Removal Pieces at Row 20 Cal 54 Piece 6 23.5 Inches Piece 5
.'38 Inches PIece 4
- 28.25 Inches Piece 3 25.875 Inches Piece 2 33.8125 Indies
.625 inch machined away Piece 1 20 Inches 1 Inch machined away Figure 1. Pulled tube diagram - SG 11 tube no. R20C54 42
A ARE VA 51-5046570-01 Figure 2. Receipt photograph of 1 H TSP intersection (section 3) at 0 degrees. Bottom (in SG) is to the left.
3000 2500 2000 2 1500 0.
1000 500 rll
(vI__
I I
rM
0.010 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0.000 I0 a.
0, e
EU U-0 200 400 600 Elapsed Time (seconds) 800 1000 12C I-Pressure at Defect -Low Flow Meotr I Figure 3. Room temperature leak rate for SG 11 tube no. R20C54, section 3 (1 H TSP) 43 coI
A AR EVA 51-5046570-01 e
Cl 100 90 80 70 60 50 40 30 20 10 0
-4 A "-,<,
7%
Arz-
'
"A,%
El /'
I /
W
1
J\\4
1
I A L 0.40
-0.30
-0.20
-0.10 0.00 0.10 0.20 Axial Distance from Center of I H TSP, inches 0.30 0.40
_- Before Tube Pull --
After Tube Pull A Before Pressure Test After Pressure Test Figure 4. Axial crack NDE profile at 19° (SAI #1) at 1 H TSP location for tube no. R20C54 00 90 80 70 60 SO 40 30 20 10 0
-0 IK
/I
0'T /7 N V t ill
11, jII I
I A
I i
I IIII
I I
.40
-0.30
-0.20
-0.10 0.00 0.10 0.20 Axial Distance from Center of IH TSP, Inches 0.30 0.40 Before Tube Pull -i-After Tube Pull ---
Before Pressure Test After Pressure Test I Figure 5. Axial crack NDE profile at 330° (SAI #2) at 1H TSP location for tube no. R20C54 44 CQ2-
A AR EVA 51-5046570-01 8o 70 60
£ 40 a.
30 10 20 10 0
4I I
lI I II 0.40
-0.30
-0.20
-0.10 0.00 0.10 0.20 Axial Distance from Center of I H TSP, Inches 0.30 0.40 l-_.- Before Tube Pull --wAfter Tube Pull A Before Pressure Test -
After Pressure Testl Figure 6. Axial crack NDE profile at 292° (SAI #3) at 1 H TSP location for tube no. R20C54 Figure 7. Post oxidation photograph of axial crack at,190 in 1H TSP intersection of tube section no.
R20C54-3. The bottom (in SG) of the tube section is to the left. (7.6X) 45 C03
A AREVA 51-5046570-01 Figure 8: 1 H TSP region at 00 (1.7X) 46
A AR EVA 51-5046570-01 Figure 9: 1 H TSP region at 45° 1.7X 47
Li U
I LI L"
LI-L ~
L LI zA AREVA 51-5046570-01 Figure 10: lH TSP region at 90° 1.7X 48
L Ii i L
iI It A
AREVA 51-5046570-01 Figure 11: IH TSP region at 1350 1.7X 49
A AR EVA 51-5046570-01 Figure 12: lH TSP region at 180° 1.7X 50
A AREVA 51-5046570-01 Figure 13: 1H TSP region at 225° 1.7X 51
A AR EVA 51-5046570-01 Figure 14: 1H TSP region at 2700 1.7X 52
A AREVA 51-5046570-01 Figure 15: lH TSP region at 315° 1.7X 53
A AR EVA 51-5046570-01 Figure 16: 2H TSP region at 00 1.7X 54
A AR EVA 51-5046570-01
-
-' -fl'E$r'
-S
,-
t4'-
k 4
fr' 4
4 Figure 17: 2H TSP region at 450 1.7X 55
A AREVA 51-5046570-01 Figure 18: 2H TSP region at 900 1.7X 56
A AR EVA 51-5046570-01 Figure 19: 2H TSP region at 1350 1.7X 57
A AREVA 51-5046570-01 Figure 20: 2H TSP region at 1800 1.7X 58
A AREEVA 51-5046570-01 Figure 21: 2H TSP region at 2250 1.7X 59
A AREVA 51-5046570-01 Figure 22: 2H TSP region at 2700 1.7X 60
A AR EVA 51-5046570-01
- 4"-*1
V 4
V
4 I
5
t Figure 23: 2H TSP region at 315° 1.7X 61
A AR EVA 51-5046570-01 Crack Figure 24: Axial crack at -19O in the I H TSP 25.7X 62 C0oL7
A AREVA 51-5046570-01 Qrack~s Figure 25: Small axial cracks near 2850 in 1H.
83X 63
A AREVA 51-5046570-01 P90r~rA-q I W T-qP 'I a &c_
LI A
3 15.5' 16.3' A
C*
ASP B
C TOM 10' 21.9' 26.
BOf 3'
R20C54-kA: SPARE 10' R20C54-3B: I H BURST SPECIMEN 11.9 R20C543C: SPARE 4.4' R20C54-3B { 1 H BURST SPECIMEN }
1 I1 3
l 5.6' 6.4' 11.
BOTTOM 7'
R20C5443B1: SPARE 5.6' R20C54-3SB2 1H TSP REGION 0.8' R20C54-3B3: SPARE 5.3' Figure 26: Overall sectioning diagram for R20C54-3B (I H TSP)
R20C54-3B2 (1 H TSP) 0 A
FISHMOU 900- _
B1
,B2: B3 270°- _
360° '
0 Bottom 04' 0.5' 0.8' THAT 19° R20C54-3B2A: SEM FRATOGRAPHY 0.8' R20C54-3B2B1: TRANSVERSE METALLOGRAPHY 0.4' R20C54-3B2B2: TRANSVERSE METALLGRAPHY 0.1' R20C54-3B2B3: SPARE 0.3'
-va-METALLOGRAPHIC FACE EXAMINED EDDY CURRENT SECONDARY CRACK LOCATIONS Figure 27: Sectioning of R20C54-3B2 for fractography and metallography 64
A AREVA 51-5046570-01 R20C54-4 (FREESPAN)
B C
- D12 D3 BOTTOM 2.0" 14.1' 26.2' 26.6-28.Z R20C544A: BULK CHEMISTRY 2.0' R20C54-4B: FREESPAN BURST SPECIMEN 12.1' R20C54-4C: TENSILE TEST I-21 R20C54-4D1: LONGITUDINAL METALLOGRAPHY 0.4" R20C54-4D2: SPARE 0.4" R20C54-4D3: SPARE 1.6' R20C54-4B 1
- 2, 3
BOTTOM 4.0-4.8" 11.9" R20C54-4B1: SPARE 4.0" R20C54-4B2: FISHMOUTH BURST REGION 0.8' R20C5414B3: SPARE 7.1" Figure 28: Overall sectioning diagram for R20C54-4 (free span) la FISHMOUTH AT 3500 360° L BOTTOM 0.8B R20C54-4B2A: SEM 0.8" R20C54-4B2B: SPARE 0.8" Figure 29: Sectioning of R20C54-4B2 burst region for fractography 65
A AREVA 51-5046570-01 R20C54-5 { 2H TSP }
11.8" 12.6' A
B C
BOTTOM 6.2 18.3B R20C5S4-5A SPARE 6Z R20CS4-5B: 2H BURST SPECIMEN 12.1' R20C5S4-5C: SPARE 17.6" R20C54-5B { 2H BURST SPECIMEN }
BOTTOM i 2AA 2Z 2.r 3A
]
1 5.4' 6.3" 3C 11.7 R20CS4-5B1: SPARE 2.Z R20CS4-5B2A: SEM 0.5' R20C54-5B2B: SPARE 0.5' P20054-5B3A: SPARE 2.7" R20054-5B3B: SECTION CONTANING 2H TSP 0.9" R20C5B583C: SPARE 5.4' Figure 30: Overall sectioning diagram for R20C54-5 (2H TSP)
R20C54-5B3B (2H TSP) 0"-
2E
--- B1 ---- - ------ -
90W.
2A.
FISHMOUTIH AT 30" 45" R20C54-583B1: SEM FRACTOGRAPHY/ RADIAL GRIND 0.9' R20C54-513B2A: RADIAL GRIND 0.
12(r-R20C54-5B382B: SPARE 0.9" R20C54-SB3B2C: RADIAL GRIND 0.9" R20CS4-SB3B2D: SPAPR 0.9" R2054-.513B2E: RADIAL GRIND 0.9" tW4-_
2B 270"-
360"-
20 2D 315" 0..
... I
.9 r
Figure 31: Sectioning of R20C54-5B3B for fractography and metallography 66
A ARE VA 51-5046570-01
- )
Figure 32: 1 H TSP region at 00 after burst testing.
1.7X 67
A AREVA 51-5046570-01 Figure 33: IH TSP region at 45° after burst testing.
1.7X 68
A AREEVA 51-5046570-01 Figure 34: IH TSP region at 900 after burst testing.
1.7X 69
A AREEVA 51-5046570-01 Figure 35: IH TSP region at 1350 after burst testing.
1.7X 70
A AREVA 51-5046570-01 Figure 36: IH TSP region at 1800 after burst testing.
1.7X 71
A AREVA 51-5046570-01
",, I Figure 37: IH TSP region at 2250 after burst testing.
1.7X 72
A AR EVA 51-5046570-01 Figure 38: IH TSP region at 2700 after burst testing.
1.7X 73
A AREVA 51-5046570-01 Figure 39: IH TSP region at 3150 after burst testing.
1.7X 74
A AREVA 51-5046570-01 Figure 40: Burst centered at 190 in IH TSP region.
1.7X 75
-A AREVA 51-5046570-01 Figure 41: Oxidized corrosion area on counterclockwise burst rupture surface of I H TSP.
8X 76
A ARE VA 51-5046570-01 Figure 42: Oxidized corrosion area on clockwise burst rupture surface of IH TSP. 8X 77
A AREVA 51-5046570-01 Crack Figure 43: Secondary crack near 3500 in 1 H TSP, extending from -0.1 inches to -0.2 inches from the bottom of the TSP region. 16.6X 78 CO&
A AR EVA 51-5046570-01 Cracks I
Figure 44: Secondary cracks near 3550 in I H TSP, extending from -0.5 inches to -0.7 inches From the bottom of the TSP region. 16.6X 79 C0n
A AREVA 51-5046570-01 Figure 45: Fish mouth burst rupture at 3500 in free span section. 1.7X 80
A AREVA 51-5046570-01 P
,-i
,. Pl.
4 -
-, - , -
-
wo
!,%"'- M
-4. -4 a
Li Figure 46: 2H TSP region at 00 after burst testing.
1.7X 81
A AREVA 51-5046570-01 Figure 47: 2H TSP region at 450 after burst testing.
1.7X 82
A AREr VA 51-5046570-01 Figure 48: 2H TSP region at 900 after burst testing.
1.7X 83
A AR EVA 51-5046570-01 Figure 49: 2H TSP region at 1350 after burst testing.
1.7X 84
A AREVA 51-5046570-01 C.
Figure 50: 2H TSP region at 1800 after burst testing.
1.7X 85
A AREEVA 51-5046570-01 Figure 51: 2H TSP region at 2250 after burst testing.
1.7X 86
A AR EVA 51-5046570-01 Figure 52: 2H TSP region at 2700 after burst testing.
1.7X 87
A AR EVA 51-5046570-01 Feb Figure 53: 2H TSP region at 315°1 after burst testing.
1.7X 88
I I Ii Ii i L
L Li' I
Li A
AR EVA 51-5046570-01 Figure 54: Burst centered at 300 in 2H TSP region.
1.7X 89
.A ARE VA 51-5046570-01 Figure 55: Counterclockwise burst rupture surface in 2H TSP. 8X 90
A AREVA 51-5046570-01 Figure 56: Apex of counterclockwise burst rupture surface in 2H TSP. 16.6X 91
A R
E51-5046570-01 ARENVA Figure 57: Clockwise burst rupture surface in 2H TSP. 8X 92
A AREVA 51-5046570-01 Figure 58: Apex of clockwise burst rupture surface in 2H TSP. 16.6X 93
A AREVA 51-5046570-01 0O0
.85"
- =
BURST FISHMOUTH (C/L-300) 1 1: INTERGRANULAR CORROSION
.9, I-
.75" -I BOTTOM TSP TOP TSP Figure 59: Areas of intergranular (cellular) corrosion in 2H TSP Note: The above measurements are based on visual observation of the burst tube section and are not intended to be exact representations of the preburst areas of corrosion.
94
.~c::
t:., r r-- rr-r-
r:: (:w rz: rr rz: r: r:
r-:
EZ A
AR EVA
- 51-5046570-01 AREV.
Figure 60A: Secondary electron image of IH burst rupture surface. 14.4X I
I
.I I i.
IIIi.
Figure 606: Backscattered electron image of IH burst rupture surface.
14.4X Figure 60: SEM mosaics of I H burst rupture surface (bottom to left) co VI
A AR EVA 51-5046570-01 Figure 61: SE image of bottom edge of IGSCC on burst rupture surface of I H TSP. 50X Figure 62: BSE image of bottom edge of IGSCC on burst rupture surface of IH TSP. SOX 96
L:
i I"
Li Li LI' Li L
Li LI Li LiLi Li ifI A
AREVA 51-5046570-01 Figure 63: SE image showing transition to 100% TW IGSCC on burst rupture surface of IH TSP. 5OX Figure 64: Detail of transition area shown in box in Figure 66. 15OX 97
L L
L Li A
AR EVA 51-5046570-01 Figure 65: BSE image of transition area to 100% IGSCC on burst rupture surface of I H TSP. 5OX 98
A AREVA 51-5046570-01 Figure 66: SE image of top edge of IGSCC on burst rupture surface of I H TSP. 50X Figure 67: BSE image of top edge of IGSCC on burst rupture surface of I H TSP. 50X 99
A AR EVA 51-5046570-01 0.06 0.05 CO 0
0.
C, 0.04 0.03 0.02
~~~~~I 1,,I,,,,I,...
,11 L
0.01 0
0 0.1 0.2 0.3 0.4 0.5 0.6 Axial Distance from Bottom of IGSCC, inches 0.7 0.8 Figure 68a: Measured crack depth on burst rupture surface in IH TSP 100 0.
0.
(U 1E O.
80 60 40 0
te b ei,,...It.e f. Ta.I 20 0
0 0.1 0.2 0.3 0.4 0.5 0.6 Axial Distance from Bottom of IGSCC, Inches I-l-Fractography Data A-d-RPC Data (SAI #1) I 0.7 0.8 Figure 68b: Comparison of measured crack depth vs. post leak rate RPC data Figure 68: Measured depth of IGSCC (SAI #1) in IH TSP 100
r.:
z r r-: r c: rz : r-::
r :
rz r:
r-rr: rz:
L..
r
- rz
=r:
A AR EVA 51-5046570-01 I
I 3,.-,
0 I>
3' 3
.3
-/
. I I
4
.: 5 :
Figure 69A: Secondary electron image of 2H burst rupture surface. 11 4X
.,3 33 3
d
,g ;'
3
XSiw 33
- a)I3:'
3'X
-t<" -T f
W image of 2H burst rupture surface.
11.4X i
r..e.
6 6.
B..
I ck
,s Figure 69B.: Backscattered 0
Figure 69: SEM mosaics of 2H burst rupture surface (bottom to left)
A ARE VA 51-5046570-01 Figure 70: SE image of bottom edge of IGSCC on burst rupture surface of 2H TSP. 50X Figure 71: BSE image of bottom edge of IGSCC on burst rupture surface of 2H TSP. 50X 102
A AREVA 51-5046570-01 Figure 72: SE image of central region of burst rupture surface of 2H TSP. 50X Figure 73: BSE image of central region of burst rupture surface of 2H TSP. 50X 103
A AR EVA 51-5046570-01 Figure 74: SE image of top edge of IGSCC on burst rupture surface of 2H TSP. 50X Figure 75: BSE image of top edge of IGSCC on burst rupture surface of 2H TSP. 50X 104
A AREVA 51-5046570-01 0.030 0.025 on 0.020 0
CM 0.015 0
D 0.010 0.005 0.000 4-0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.0 Distance From Bottom of 2H TSP, inches Figure 76: Plot of depth of intergranular corrosion in 2H TSP (Section R20C54-5B3) 0 105
A AR EVA 51-5046570-01 Figure 77: Free span burst rupture surface. loX Figure 78: Typical non-corroded ductile area on free span burst rupture surface.
SE image.
500X 106
A AREVA 51-5046570-01 Figure 79A: BSE image of an area on 2H burst rupture surface. 5000X mi Specbne: R20C54-583 EDS of sea 1, nage 116472.
Utcoed, 10 kV.
Aom : OSi, S*, K, Cr Fe, Ni Possim Trae: Mg S* - Coonfd usig WDS WDS mggest possbl (at ditcsfty Nmt) ce Pb.
Si Figure 79B: EDS spectrum of area I in Figure 79A, showing presence of sulfur.
Figure 79: EDS analysis of area on 2H burst rupture surface.
107 CIO
L, L
Li Li Li LI, U
A AREVA 51-5046570-01 Figure 80: Typical copper colored deposits in free span areas. 1.7X 108
A AREVA 51-5046570-01 Figure 81A: BSE image of typical copper colored deposit area. 50X ou Spechnn: R20CS4-SB2A EDS of ares 1, kTuge 116330.
Ukcoatsd, 20 kV.
Elements: C, O, Al, Si, Cr, I, Fe, M, Zn Low conc: P and/or Zr, S and/or Ho 0
jzn U
Figure 81 B: EDS analysis of area I in Figure 74A showing Al, Zn, 0.
Figure 81: SEMIEDS analysis of copper colored deposits on tube OD.
109 CO3
A AREVA 51-5046570-01 Figure 82: 53% TW indication near 2980 in centerline of IH TSP, corresponding to approximate location of secondary eddy current indication.
46X Figure 83: Etched microstructure of crack shown in Figure 82. 480X 110
A AREVA 51-5046570-01 Figure 84: 40% TW indication near 3300 at centerline +0.1 inches of IH TSP, corresponding to approximate location of secondary eddy current indication.
59X Figure 85: Etched microstructure of cracking shown in Figure 84.: 175X 111
A AREEVA 51-5046570-01 Figure 86: Overall mosaic of 5B3BB1 (first face) 11.2X 112
A AR EVA 51-5046570-01 Figure 87: Area "A" in Figure 86.
146X Figure 88: Area "B" in Figure 87.
99X 113
A ARE VA 51-5046570-01 Figure 89: Area "C" in Figure 80.
99X 114
A AREVA 51-5046570-01 Figure 90:- Overall mosaic of 5B3BBI (second face) 10.6X 115
A AREVA 51-5046570-01 Figure 91: Area "AA" in Figure 90. 146X
-- Figure 92: Area "B" in Figure 90. 146X 116
A ARIEVA 51-5046570-01 Figure 93: Area "C" in Figure 90. 99X 117
,,=;S v He
A AR EVA 51-5046570-01 Figure 94: Overall mosaic of 5B3BB1 (third face)
I0.0X 118
A AR EVA 51-5046570-01 Figure 95: Area "A" in Figure 94. 146X Figure 96: Area "B" in Figure 94. 146X 119
A AR~EVA 51-5046570-01 Figure 97: Overall mosaic of 5B3BB1 (fourth face) 9.9X 120 X
a Y
E
A AREVA 51-5046570-01 Figure 98: Area "A" in Figure 97. 99X Figure 99: Area "B" in Figure 97. 146X 121
A AREVA 51-5046570-01 Figure 100: Corrosion area near top of 2H TSP in 5B3B2A (first face). 14.6X 122
A ARFEVA 51-5046570-01 Figure 101: Overall mosaic of corrosion near bottom end of 2H TSP in SB3B2A (first face). 12.6X 123
A AREVA 51-5046570-01 Figure 102: Area "A" in Figure 101. 99X Figure 103: Area "B" in Figure 101. -99X 124
A AREVA 51-5046570-01 Figure 104: Corrosion area near top of 2H TSP in 5B3B2A (second face). 14.6X 125
A ARE VA 51-5046570-01 Figure 105: Overall mosaic of corrosion near bottom end of 2H TSP in 5B3B2A (second face). 1 3.7X 126
A AR EVA 51-5046570-01 Figure 106: Area "A" in Figure 105. 99X Figure 107: Area "B" in Figure 105. 146X 127
A AR EVA 51-5046570-01 Figure 108: Corrosion area near top of 2H TSP in 5B3B2A (third face). 14.6X 128
A AREVA 51-5046570-01 Figure 109: Overall mosaic of corrosion near bottom end of 2H TSP in 5B3B2A (third
-face). -12.8X 129
A5 AR EVA 51-5046570-01 Figure 110: Area "Al" in Figure 109. 99X Figure 111: Area "B" in Figure 109. 99X 130
A ARE VA 51-5046570-01
, ": 1, I
. 4.....
Figure 112: Corrosion area near top of 2H TSP IN 5B3B2A (fourth face). 14.6X Figure 113: Area-"A" in Figure 112. 99X 131
A AR EVA 51-5046570-01 1=-
M ML Figure 114: Overall mosaic of corrosion near;bottom end of 2H TSP in 5B3B2A (fourth face). 1 7.5X 132
A AR EVA 51-5046570-01 Figure 115: Area "A" in Figure 114. 146X 133
A AR EVA 51-5046570-01 Figure 116: Corrosion area neartop of 2H TSP in 5B3B2A (fifth face). 14.6X Figure 117: Detail of area shown in box in Figure 116. 198X 134
A AR EVA 51-5046570-01 Figure 118: Bottom end of 2H TSP in 5B3B2A (fifth face). 014.6X Figure 119: Detail of area shown-in box in Figure 118. 496X 135
A AR EVA 51-5046570-01 Figure 120: Overall mosaic of corrosion on 5B3B2C (first face). 10.OX 136
A AREVA 51-5046570-01 Figure 121: Area "A" in Figure 120. 492X Figure 122: Area "B"- inFigure120.' 492X 137
A AR EVA 51-5046570-01 Figure 123: Area "C" in Figure 120. 99X Figure 124: Area "D" in Figure 120. 199X 138
A ARIEVA 51-5046570-01 Figure 125: Overall mosaic of corrosion on 5B3B2C (second face). 9.9X 139
A AREVA 51-5046570-01 I.i I U
I I
k I-,
Figure 126: Area "A" in Figure 125. 99X Figure 127: Area "B" in Figure 125. 146X 140
A AREVA 51-5046570-01 Figure 128: Overall mosaic of corrosion on 5B362C (third face). 11.7X 141
A AREEVA 51-5046570-01 Figure 129: Area "A" in Figure 128. 99X Figure 130: Last remnants of corrosion shown previously in lower left of Figure 125 (third face now). 49.6X 142
A AREVA 51-5046570-01 Figure 131: Last remnants of corrosion shown previously in upper portion of Figure 128 (fourth face now). 146X 143
A: -
AREVA-51-5046570-01 Figure 132:
Overall mosaic of 5B3B2E (first face)
I O.4X 144
A AR EVA 51-5046570-01 Figure 133: Area "A" in Figure 132. 146X Figure 134: Area "B" in Figure 132. 146X 145
,A.
AR EVA-51-5046570-01 Figure 135:
Overall mosaic of 5B3B2E (second face) 9.7X 146
A AREVA 51-5046570-01 Figure 136: Area "A" in Figure 135. 146X Figure 137: Area "B" in Figure 135. 146X 147
L L
L L
I :
IL~
L I i L
L I.
L A
AREVA 51-5046570-01 0
= CO t,
0 t C
.0 C =
0W (U
3 Jun.. 2004 File: R20C544C 21 Cl 6
d o to -;
,a C;
V, o f-0 )
C)
C.
a)
S 0)
CU 0
, o; 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 Engineering Strain-Figure 138: Engineering stress/strain curve for tensile specimen R20C54-4C 148
A ARIEVA 51-5046570-01 Figure 139: Typical carbide distribution in R20C54. 678X Figure 140: Typical microstructure in R20C54, corresponding to same area as Figure 80.
678X 149