ML20207Q346
| ML20207Q346 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee  |
| Issue date: | 01/12/1987 |
| From: | Hoffman J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | |
| Shared Package | |
| ML20207Q343 | List: |
| References | |
| NUDOCS 8701270195 | |
| Download: ML20207Q346 (41) | |
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(- ENCLOSURE 1 u ~,...)
Vermont Yankee Nuclear Power Station Justification for Multi-Cycle Operation for Vermont Yankee Core Spray Nozzle Weld Overlays e%
X, s' \ Vermont Yankee Nuclear Power Corporation JowN R. H orrw AN. P.E. 4 kY M YANMEE ATOMIC ELECTRIC COMPANY sets woectsTEn none F n&MINGuaw ma S S AC e*W5 ttTS 08 70s 8701270195 870112 R ADOCK 05000271 PDR
t t TABLE OF CONTENTS 1 . 8unun a r y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1
- 2. Background.............................................. 2-1 3 . We l d Ov e r l a y De s i gn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1
- 4. Ex tended Operat i on wi th Wel d Overl ays. . . . . . . . . . . . . . . . . . . 4-1 4.1. A s- b u i l t D a t a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1
- 4. 2 . De s i g n S t r e s s D a t a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1
- 4. 3 . F l aw G r ow t h S t u d i e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1
- 5. Pl ans f or 1987 Re f u e l i n g 0u t age . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 d . Sununar y of Con se r v a t i sms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
- 7. Conclusion.............................................. 7-1
- 8. References.............................................. 8-1 Appendices A. Supporting Data for Figures..............................A-1 B. Stress Data for Core Spray Nozzle and Safe End...........B-1 C. Ul t r ason i c I n sp e c t i on Da t a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
i e LI ST OF FIGURES 2-1: Reactor Pressure Vesse1................................ 2-1 2-2: Core Spray Safe End and Nozz1e......................... 2-2 2-3: Sa f e En d We l d De t a l 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 3-1: Comp l e t e d We l d 0v e r l ay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 4-1: Core Spray Nozzle Flaw Growth Rate - NRC NUREG-0313 Dat.4-2 4-2: Inconel Flaw Growth Rate Data.......................... 4-4 4-3: Core Spray Nozzle Flaw Growth Rate - Inconel Data...... 4-5 4-4: Core Spray Nozzle Stress Intensity vs Flaw Depth Profil.4-5 4-5: NUREG-0313 Residual Stress Profile..................... 4-6 e w - - - ------ ,
F t Justification for Multi-cycle Operation for Vermont Yankee Core Spray Nozzle Weld Overlays
- 1. Sunnary In May 1986 Vermont Yankee applied weld overlays to the safe end to nozzle welds on the two core spray nozzles on the reactor pressure vessel. At that time the USNRC authorized operation for one fuel cycle. This report presents the results of a study performed to justify continued operation beyond one fuel cycle.
As will be' demonstrated in the following sections, even the most conservative assessment of the overlay design supports operation beyond Cycle 13 (the plant is currently in Cycle 12). A realistic evaluation demonstrates that operation to end of life with the overlays is acceptable. l l l l l l l I t 1-1
I r
2. Background
The two core spray nozzles (called the H5 nozzles) are located on the shell portion of the reactor vessel, 180 degrees apart, as shown in Figure 2-1. The nozzles and safe ends are sized for a 10 inch connection, with a reducer being used to mate with the 8 inch core spray piping, as shown in Figure 2-2.
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- The nozzle is f abricated from SA50_8 CL2 low alloy steel; the safe end is fabricated from SB166 Alloy 600 (Inconel 400). Both components are forgings.
The nozzle is clad with Inconel 182 weld metal to allow for welding the safe end to the nozzle without having to perform a subsequent post weld heat treatment. The safe end is welded to the nozzle with Inconel 82 weld metal . The details of the weld joint are shown in Figure 2-3.
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't wn.e er e a sY$?' ws s Fig. 2-2: Core Spray Safe End and Nozzle During ultrasonic examination in April 1986 indications typical of intergranular stress corrosion cracking (IGSCC) were detected in the Inconel 182 weld metal on the face of the nozzle. Since Inconel 182 has been shown to be susceptible to IGSCC the joints were considered flawed and a weld overlay.
was applied. A description of the examination technique and a sumary of the Indications found is contained in Appendix C. 2-2 --,~........_.c..,,m-. . _ _ _ _ . - _ _... ,. ....,..,,. , , ,.
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- 3. Weld Overlay Design
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The weld overlay was designed in accordance with the requirements of the ASME Code, Section XI. The stress information was taken fran the original stress report for the reactor pressure vessel, Reference 2. Because the SA508 CL2 nozzle material is a hardenable material, specialized welding procedures were developed to allow welding without a subsequent post weld heat treatment. The procedures were based on the concepts discussed in References 3 and 4. Nockup testing was performed to develop site specific welding procedures. Qualification testing was performed to demonstrate that the desired material toughness recovery was achieved. The basic approach was to apply a three layer Inconel weld overlay using a butter-temper process to achieve the desired post weld heat treatment effect as well as to provide a minimum 0.125 inch thick weld deposit so that subsequent welding could be performed without any special controls relative to material embrittlement of the nozzle. Based on the design stress conditions a weld overlay thickness of 0.41 inches was required; allowing f or the 0.125 butter-temper layers, a total overlay thickness of 0.535 inches was required. The finished weld overlay is shown in Figure 3-1. 3-1
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- 4. Extended Operation with Weld Overlays As stated above, USNRC authorization was received for operation with the N5 weld overlays. In order to be able to schedule replacement of the core spray safe ends with minimum impact on plant outage time operation beyond Cycle 13 (currently scheduled to end in Spring 1989) is desired.
In order to achieve this goal the weld overlay has been re-evaluated using as-built dimensions for the overlay and updated design information. 4.1. As-built Data The actual weld overlay thickness was measured following installation. Measurements were taken at four locations 90 degrees apart on the nozzle side and the safe end side of each overlay. The average overlay thickness was 0.571 inches. The lowest reading (at only one location) was 0.540 inches. For conservatism, 0.540 inches was selected as the installed overlay thickness. 4.2. Design Stress Data As part of the process of designing replacement safe ends a new stress analysis was performed for the core spray nozzle and safe end (Reference 5). Since this analysis represents current design methodology and analytical approaches the stresses from this analysis were used in re-evaluating the as-installed weld overlays. Using the revised stress information a minimum overlay thickness of 0.305 l Inches was determined to be required, in accordance with Reference 6. 4.3. Flaw Growth Studies Flaw growth studies were performed to determine the time period available before the original 65 percent deep flaw would grow deep enough to penetrate into the minimum required 0.305 inch overlay. l The first, and most conservative, evaluation was performed using the l criteria from NUREG-0313, Revision 2, May 1986 Draft. No credit was taken for any residual stress benefit from the weld overlay. A residual stress pattern 4-1
e . from NUREG-0313 Rev 2 was combined with the applied primary membrane, primary
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bending and secondary thermal stress from Reference 5 to create the applied stress field. The IGSCC flaw growth rate curve from NUREG-0313 Rev 2 was used. The resulting flaw depth after 30000 hours was 0.90 inches, still below the surface of the nozzle, which is 0.914 inches thick. The results of this study are shown in Figure 4-1. E
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W WE Flun sizaI le6CC Full luMil - IRC GINE Fig. 4-1: Core Spray Nozzle Flaw Growth Rate - NRC NUREG-0313 Data Laboratory data and field experience demonstrate that IGSCC flaw growth in inconel is slower than in sensitized stainless steel. Figure 4-2 shows that the available IGSCC flaw growth data for Inconel can be bounded by a curve
- defined by the following equation (Reference 9)
da/dt = 1.078 x 10-8 (K)2 26 , Using this equation for flaw growth, and the applied stress field discussed above, the predicted flaw depth after 30000 hours is .66 inches, as shown in Figure 4-3. The final evaluation considered the ef f ect of the weld overlay induced 4-2
residual stress combined with the applied stress field. Since the net stress field is compressive no flaw growth would be predicted. Figure 4-4 shows the stress intensity profile for the weld overlay. Thus it is concluded that operation beyond Cycle 13 would not result in flaw growth that would infringe on the required overlay thickness, even using the most conservative flaw growth assumptions. i . I 4-3
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- 5. Plans for 1987 Refueling Outage During the 1987 refueling outage, following Cycle 12, the weld overlays will be ultrasonically examined utilizing techniques capable of detecting flaws in the weld overlay and lack of bond between the weld overlay and the nozzle or safe end.
Ultrasonic examinations will be conducted consistent with the methods and requirements of the EPRI training program for weld overlay examination. This program will be reviewed by Vermont Yankee to determine if any adjustments to the program, procedures or qualifications are required for use with inconel weld overlay material . I P O 5-1
- 4. Summary of Ocaservatisms The results presented above demonstrate that continued operation with core spray nozzle overlays is justified.
The significance of the results is enhanced by understanding the conservatisms that are present in the evaluations. To assist that understanding the conservatisms are presented below
- 1. The ASNE Section XI flawed pipe evaluation process is conservative, as demonstrated in References 7 and 8.
- 2. Code minimum values are used for required material properties.
- 3. Bounding loads are used for the stress analysis.
- 4. The USNRC residual stress profile is a conservative approximation (i.e. underestimates) the probable as-welded residual stress profile, underpredicting the likelihood of crack arrest.
- 5. The Inconel IGSCC growth flaw curve is the upper bound of available data.
- 6. The overlay thickness used in the evaluation is the minimum value of 16 readings.
- 7. The flaw growth calculations assumed a full 360 degree flaw, even though the actual flaw was considerably smaller. The multiple flaws could be enclosed in an arc segment less than twenty percent of the nozzle circumference.
- 8. Unlike overlays on stainless steel pipe, the overlay welding does not sensitize the underlying inconel or low alloy steel basemetal. Thus, the development of IGSCC parallel to the surface of the overlay (i.e. developing " lack of bond") is not a credible event.
4-1
- 7. ConcInslen It has been demonstrated that continued operation with weld overlays on the core spray nozzles beyond Cycle 13 will not infringe on the Code required structural integrity of the weld overlays.
The realistic evaluation shows that unlimited life of the overlays is to be expected. Confirmation of that assessment will be obtained by performing an ultrasonic examination of the weld overlays during the 1987 refueling outage. i e e 0 7-1
. 8. References
- 1. Le tter f rom UR4RC to VYNPC, dated June 23, 1986 (NVY 86-113).
- 2. Chicago Bridge and Iron Stress Report 9-6202-1, Section I-S-7, August 1969.
- 3. EPRI Report NP-3614, " Repair Welding of Heavy Section Steel Components in LWRs", July, 1984.
- 4. ASME Code Case N-432, " Repair Welding Using Automatic or Nachine Gas-Tungsten Arc Welding (GTAW) Temperbead Technique, Section XI, Division 1 February 20, 1986.
- 5. General Electric Company Report 23A4904, ' Core Spray Nozzle Stress Report", December 13, 1985.
- 6. ASNE Boiler and Pressure Vessel Code, Section XI, Subsection IWB-3641, 1983 Edition thru Winter 1985 Addenda.
- 7. EPRI Report NP-4690-SR, " Evaluation of Flaws in Austenitic Steel Piping",
July 1986.
- 8. EPRI Report NP-4883-SP, " Evaluation of Flawed Pipe Experiments",
November 1986.
- 9. SIA Report SIR-86-015, " Development of Inconel Weld Overlay Repair for Low Alloy Steel Nozzle to Safe End Joint", Structural Integrity Associates, July 1986 (Draft Report).
8-1
i l A. Supporting Data for Figures t A-1
pc-CRACK
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(C) COPYRI GHT 1984, 1986 , STRUCTURAL INTEGRITY ASSOCI ATES, INC. I SAN JOSE, CA (408)978-8200 VERSI ON 1.1 WELD OVERLAY SIZING EVALUATION WELD OVERLAY SIZING FOR CIRCUMF. CRACK, WROUGHT / CAST STAINLESS VERMONT YANKEE CORE SPRAY SAFE END WELD OVERLAY WALL - THI CKNESS= 0.9140 MEMBRANE STRESS = 3763.2000 BENDING STRESS = 4984.7000 STRE SS RAT I O= 0.3754 ALLOWABLE STRESS =23300.0000 FLOW STRESS =69900.0000 L/CI RCUM 0.00 0.10 0.20 0.30 0.40 0.50 FINAL A/T 0.7500 0.7500 0.7500 0.7500 0.7500 0.7500 OVERLAY THICKNESS 0.3047 0.3047 0.3047 0.3047 0.3047 0.3047 END OF pc-CRACK 4 f 4 a , - - . - - - ~ . . w ,-, - - - , . - - - ~ , . - - . . , - . - - . - - , - - - - - . . _ - - - - - . - - _ . . - - - - . ~ . , ,. .,,---- _-_ = - - . - , - - . ,
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- pc-CRACK (C) COPYRI GHT 1984, 1986 STRUCTUh4L INTEGRITY ASSOCI ATES, INC.
' 944 JOSE , CA (408)978-8200 (ERSI ON 1.1 STRESS CORROSION CRACK GROWTH ANALYSIS VY CORE SPRAY N0ZZLE IGSCC FL' A W GROWTH - NRC MODEL ( Fi gure 4 -1 )
; INITI AL CRACK SIZE = 0.5940 WALL THICKNESS = 1.4540 MN< CRACK SIZE FOR SCCG= 1.1490 g.
STRESS CORROSION CRACK GROWTH LAW (S) N Kthres K1C UN4 ID C NRC 3,5900E-08 2.1610 0.0000 500.0000 STRESS COEFFICIENTS CO C1 C2 C3 CASE ID VYWELDOVL -13.6306 -112.8590 214.8675 -70.7867 NRCRESI D 1.0211 -8.1486 13.4647 -5.9335 NRC 38.8020 -309.6470 511.6590 -225.4730 APPLIED 10.9650 0.0000 0.0000 0.0000 Kmax CASE ID SCALE FACTOR NRC 1.00 APPLI ED 1.00 TIME PRINT J TIME INCREMENT INCREMENT l 30000.0 500.0 3000.0 Cb4CK MODEL CIRCUMFERENTI AL CRACK IN CYLINDER (T/R=0.1) 2--------- C RACK -------------------------ST RE S S I NT ENS I TY FACTOR ---------- ; CASE CASE CASE CASE
, DEPTH Vn4ELDOJL NRCRESID NRC APPLIED 0.27 10.36 3.27 0.0230 -4.50 O.0460 -6.97 0.34 13.11 4.64 0.0689 -9.23 0.38 14.27 5.71 0.0919 -11.41 0.38 14.53 '
6.62 i 0.1149 -13.54 0.37 14.20 7.44 0.1379 -15.63 0.35 13.44 8.18
-17.77 0.33 12.45 8.92 0.1609 0.30 11.25 9.64 0.1838 -19.93 10.35 0.2068 -22.07 0.26 9.87 0.22 8.34 11.03 O.2298 -24.18 11.70 0.2528 -26.26 0.18 6.71 l
, _ . . , _ ~ . _ . . - _ . . _ - - . - _ - . . . _ . . _ , . _ _ . _ _ _ . . . . - _ . . . - . _ . - . _ _ , . _ , . _ _ _ . _ - _ . _ . _ . _ . _ . . . _ . . . - - .
PAGE 2 pc-CRdCK VERSION 1.1 0.2758 -28.30 0.13 5.01 12.35 0.2987 -30.35 0.09 3.29 13.02 0.3217 -32.46 0.04 1.57 13.73 0.3447 -34.52 -0.00 -0.16 14.43 0.3677 -36.53 -0.05 -1.88 15.14 0.3907 -38.49 -0.09 -3.59 15.85 0.4136 -40.38 -0.14 -5.26 16.55 0.4366 -42.21 -0.18 -6.88 17.26 0.4596 -44.20 -0.21 -8.12 18.12 0.4826 -46.11 -0.24 -9.27 18.99 0.5056 -47.95 -0.27 -10.33 19.87 O.5285 -49.69 -0.30 -11.28 20.76 0.5515 -51.34 -0.32 -12.13 21.66 0.5745 -52.89 -0.34 -12.85 22.57 0.5975 -54.44 -0.36 -13.52 23.52 0.6205 -55.93 -0.37 -14.10 24.50 0.6434 -57.32 -0.38 -14.58 25.48 0.6664 -58.59 -0.39 -14.94 26.48 0.6894 -59.75 -0.40 -15.19 27.49 0.7124 -60.77 -0.40 -15.33 28.52 0.7354 -61.77 -0.41 -15.46 29.58 0.7583 -62.81 -0.41 -15.68 30.71 0.7813 -63.73 -0.42 -15.83 31.85 0.8043 -64.50 -0.42 -15.90 33.00 0.8273 -65.13 -0.42 -15.89 34.17 0.8503 -65.62 -0.42 -15.81 35.35 0.8732 -65.96 -0.41 -15.63 36.54 0.8962 -65.90 -0.37 -14.24 37.84 0.9192 -65.66 -0.34 -12.73 39.15 0.9422 -65.22 -0.29 -11.10 40.47 0.9652 -64.59 -0.25 -9.36 41.81 0.9881 -63.76 -0.20 ~7.52 43.17 1.0111 -62.73 -0.15 -5.60 44.53 1.0341 -61.85 -0.12 -4.57 46.01 1.0571 -60.88 -0.10 -3.91 47.54 1.0801 -59.66 -0.08 -3.20 49.08 l 1.1030 -58.20 -0.07 -2.49 50.64 1.1260 -56.48 -0.05 -1.77 52.22 1.1490 -54.51 -0.03 -1.07 53.81 TIME KMAX DA/DT DA A A/THK l 3000.0 10.16 5.3865E-06 0.0027 0.6098 0.419 6000.0 10.46 5.7365E-06 0.0029 0.6265 0.431 9000.0 10.86 6.2204E-06 0.0031 0.6446 0.443 12000.0 11.39 6.8930E-06 0.0034 0.6644 0.457 l I 15000.0 12.08 7.8273E-06 0.0039 0.6866 0.472 18000.0 13.01 9.1839E-06 0.0046 0.7123 0.490 21000.0 14.20 1.1104E-05 0.0056 0.7431 0.511 24000.0 15.70 1.3776E-05 0.0069 0.7808 0.537 27000.0 17.92 1.8344E-05 0.0092 0.8294 0.570
PAGE 3 pc-CRACK VERSION 1.1 30000,0 22,29 2.9390E-05 0.0147 0.8997 0.619 END OF pc-CRACK 1 i i 1 t e
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' (C) COPYRI GHT 1984, 1986 STRUCTURAL INTEGRITY ASSOCIATES, INC.
- S44 JOSE, CA (408)978-8200
' VERS I ON 1.1 STRESS CORROSION CRACK GROWTH ANALYSIS 4
' VY CORE SPRAY N0ZZLE IGSCC FLAW GROWTH - INCONEL W/NRC RESIDUAL STRESS ( Fi g a rc
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INITI AL CRACK SIZE = 0.5940 1 WALL THI CKNESS= 1.4540 MNK CRACK SIZE FOR SCCG= 1.1490 STRESS CORROS!ON CRACK GROWTH LAW (S) LAW ID C N Kthres K1C q INCONEL 1.0780E-08 2.2600 0.0000 500.0000 1 STRESS COEFFICI ENTS CASE ID CO C1 C2 C3 i' VYWELDOVL -13.6306 -112.8590 214.8675 -70.7867 NRCRESI D 1.0211 -8.1486 13.4647 -5.9335 l NRC 38.8020 -309.6470 511.6590 -225.4730 APPLI ED 10.9650 0.0000 0.0000 0.0000 i 5 Kmax CASE ID SCALE FACTOR APPLIED 1.00 i NRC 1.00 1
'j TIME PRINT TIME INCREMENT INCREMENT 2 30000.0 500.0 3000.0 i
t j CR4CK MODEL:CI RCUMFERENTI AL CRACK IN CYLINDER (T/R=0.1) CRACK -------------------------STRESS INTENSITY FACTOR------------------------ DEPTH CASE CASE CASE CASE VYWELDOVL NRCRESID NRC APPLIED 0.0230 -4.50 0.27 10.36 3.27 0.0460 -6.97 0.34 13.11 4.64 l 0.0689 -9.23 0.38 14.27 5.71
- 0.0919 -11.41 0.38 14.53 6.62 0.1149 -13.54 0.37 14.20 7.44 0.1379 -15.63 0.35 13.44 8.18 0.1609 -17.77 0.33 12.45 8.92 O.1838 -19.93 0.30 11.25 9.64 0.2068 -22.07 0.26 9.87 10.35 0.2298 -24.18 0.22 8.34 11.03 i
0.2528 -26.26 0.18 6.71 11.70 t s I 1 I
--4, - _ _ _
VERSION 1.1 PAGE 2 pc CRACK 0.2758 -28.30 0.13 5.01 12.35 0.-2987 -30.35 0.09 3.29 13.02 0.3217 -32.46 0.04 1.57 13.73 0.3447 -34.52 -0.00 -0.16 14.43
- 0. 3 677 -36.53 -0.05 -1.88 15.14 0.3907 -38.49 -0.09 -3.59 15.85 0.4136 -40.38 -0.14 -5.26 16.55 0.4366 -42.21 -0.18 -6.88 17.26 0.4596 -44.20 -0.21 -8.12 18.12 0.4826 -46.11 -0.24 -9.27 18.99
- 0.5056 -47.95 -0.27 -10.33 19.87 0.5285 -49.69 -0.30 -11.28 20.76 0.5515 -51. 34 -0.32 -12.13 21.66 0.5745 -52.89 -0.34 -12.85 22.57 0.5975 -54.44 -0.36 -13.52 23.52 0.6205 -55.93 -0.37 -14.10 24.50 0.6434 -57.32 -0.38 -14.58 25.48 0.6664 -58.59 -0.39 -14.94 26.48 0.6894 -59.75 -0.40 -15.19 27.49 0.7124 -60.77 -0.40 -15.33 28.52 0.7354 -61.77 -0.41 -15.46 29.58 0.7583 -62.81 -0.41 -15.68 30.71 0.7 813 -63.73 -0.42 -15.83 31.85 0.0043 -64.50 -0.42 -15.90 33.00 0.0273 -65.13 -0.42 -15.89 34.17 0.C503 -65.62 -0.42 -15.81 35.35 36.54 0.0732 -65.96 -0.41 -15.63 0.8962 -65.90 -0.37 -14.24 37.84 0.9192 -65.66 -0.34 -12.73 39.15 0.9422 -65.22 -0.29 -11.10 40.47 0.9652 -64.59 -0.25 -9.36 41.81 0.9881 -63.76 -0.20 -7.52 43.17 1.0111 -62.73 -0.15 -5.60 44.53 1.0341 -61.85 -0.12 -4.57 46.01
-60.88 -0.10 -3.91 47.54 1.0571 49.08 1.0 801 -59.66 -0.08 -3.20 1.1030 -58.20 -0.07 -2.49 50.64 1.1260 -56.48 -0.05 -1.77 52.22 1.1490 -54.51 -0.03 -1.07 53.81 TIME KMAX DA/DT DA A A/THK 3000.0 10.02 1.9718E-06 0.0010 S.5999 0.413 6000.0 10.13 2.0175E-06 0.0010 0.6059 0.417 9000,0 10.23 2.0649E-06 0.0010 0.6120 0.421 12000.0 10.34 2.1141E-06 0.0011 0.6183 0.425 15000.0 10.46 2.1730E-06 0.0011 0.6247 0.430 18000,0 10.61 2.2432E-06 0.0011 0.6314 0.434 21000.0 10.76 2.3171E-06 0.0012 0.6382 0.439 24000.0 10.93 2.3966E-06 0.0012 0.6453 0.444 27000.0 11.13 2.4981E-06 0.0012 0.6527 0.449
PAGE 3 pb-CRAbK VERSION 1.1 30b O O .0 11.34 2.6065E-06 0.0013 0.6604 0.454 END OF pc-CRACK k l I
e . tm
- pc-CRACK (C) COPYRI GHT 1984,'1986 STRUCTURAL INTEGRITY ASSOCI ATES, INC. - SAN JOSE , CA (408)978-8200 VERSI ON 1.1 STRESS CORROSION CRACK GROWTH ANALYSIS W CORE ' SPRAY N0ZZLE IGSCC FLAW GROWTH W/ WELD OVERLAY INITI AL CRACK SIZE = 0.5940 WALL THICKNESS = 1.4540 t%X CRACK SIZE FOR SCCG= 1.1490 STRESS CORROSION CRACK GROWTH LAW (S)
LAW ID C N Kthres K1C INCONEL 1.0780E-08 2.2600 0.0000 500.0000 STRESS COEFFICIENTS CASE ID CO C1 C2 C3 VYWELDOVL -13.4306 -112.8590 214.8675 -70.7867 NRCRESID 1.0211 -8.1486 13.4647 -5.9335 NRC 38.8020 -309.6470 511.6590 -225.4730 APPLIED 10.9650 0.0000 0.0000 0.0000 Kmax CASE ID SCALE FACTOR APPLIED 1.00 VYWELDOVL 1.00 TIME PRINT TIME INCREMENT INCREMENT 30000.0 500.0 3000.0 CRACK MODEL CIRCUMFERENTI AL CRACK IN CYLINDER (T/R=0.1) C R A C K ------------- ------------ ST R E S S I NT EN S I TY F A CT O R ------------------------ DEPTH CASE CASE CASE CASE VYWELDOVL NRCRESID NRC APPLIED 0.0230 -4.50 0.27 10.36 3.27 , 0.0460 -6.97 0.34 13.11 4.64 0.0689 -9.23 0.38 14.27 5.71 0.0919 -11.41 0.38 14.53 6.62 0.1149 -13.54 0.37 14.20 7.44 0.1379 -15.63 0.35 13.44 8.18 0.1609 -17.77 0.33 12.45 8.92 0.1838 -19.93 0.30 11.25 9.64 0.2068 -22.07 0.26 9.87 10.35 0.2298 -24.18 0.22 8.34 11.03 0.2528 -26.26 0.18 6.71 11.70
PAGE 2 pc-CRACK VERSION 1.1 0.2758 -28.30 0.13 5.01 12.35 0.2987 -30.35 0.09 3.29 13.02 0.3217 -32.46 0.04 1.57 13.73 0.3447 -34.52 -0.00 -0.16 14.43 0.3677 -36.53 -0.05 -1.88 15.14 0.3907 -38.49 -0.09 -3.59 15.85 0.4136 -40.38 -0.14 -5.26 16.55 0.4366 -42.21 -0.18 -6.88 17.26' O.4596 -44.20 -0.21 -8.12 18.12 0.4826 -46./1 -0.24 -9.27 18.99 0.5056 -47.95 -0.27 -10.33 19.87 0.5285 -49.69 -0.30 -11.28 20.76 0.5515 -51.34 -0.32 -12.13 21.66 0.5745 -52.89 -0.34 -12.85 22.57 ' 0.5975 -54.44 -0.36 -13.52 23.52 O.6205 -55.93 -0.37 -14.10 24.50 0.6434 -57.32 -0.38 -14.58 25.48 0.6664 -58.59 -0.39 -14.94 26.48 0.6894 -59.75 -0.40 -15.19 27.49 0.7124 -60.77 -0.40 -15.33 28.52 0.7354 -61.77 -0.41 -15.46 29.58 0.7583 -62.81 -0.41 -15.68 30.71 0.7813 -63.73 -0.42 -15.83 31.85 0.8043 -64.50 -0.42 -15.90 33.00 0.0273 -65.13 -0.42 -15.89 34.17 0.8503 -65.62 -0.42 -15.81 35.35
-0.41 -15.63 36.54 0.8732 -65.96 37.84 0.8962 -65.90 -0.37 -14.24 0.9192 -65.66 -0.34 -12.73 39.15 ; 0.9422 -65.22 -0.29 -11.10 40.47 0.9652 -64.59 -0.25 -9.36 41.81 0.9881 -63.76 -0.20 -7.52 43.17 1.0111 -62.73 -0.15 -5.60 44.53 1.0341 -61.85 -0.12 -4.57 46.01 1.0571 -60.88 -0.1C -3.91 47.54 1.0801 -59.66 -0.08 -3.20 49.08 1.1030 -58.20 -0.07 -2.49 50.64 1.1260 -56.48 -0.05 -1.77 52.22
, 1.1490 -54.51 -0.03 -1.07 53.81 t TIME KMAX DA/DT DA A A/THK END OF pc-CRACK I l
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- pc-CRACK (C) COPYRI GHT 1984, 1986 STRUCTUR4L INTEGRITY ASSOCIATES, INC.
SW4 J OSE , CA (408)978-8200 VERSI ON 1.1 LINEAR ELASTIC FRACTURE MECHANICS EVALUATION CORE SPRAY N0Z2LE K VS A ( F p re 4-4) Cm4CK MODEL CIRCUMFERENTI AL CRACK IN CYLINDER (T/R=0.1) WALL THI CKNESS= 1.4540 STRESS COEFFICIENTS D4SE ID CO C1 C2 C3 VYWELDOVL -13.6306 -112.8590 214.8675 -70.7867 NRCRESID 1.0211 -8.1486 13.4647 -5.9335 NRC 38.8020 -309.6470 511.6590 -225.4730 APPLIED 10.9650 0.0000 0.0000 0.0000 C RACK ------------------------ST R ESS I NT EN S I TY FACT O R------------------------ DEPTH CASE CASE CASE CASE VYWELDDVL NRCRESID NRC APPLIED 0.0230 -4.50 0.27 10.36 3.27 0.0460 -6.97 0.34 13.11 4.64 0.0689 -9.23 0.38 14.27 5.71 0.0919 -11.41 0.38 14.53 6.62 0.1149 -13.54 0.37 14.20 7.44 0.1379 -15.64 0.35 13.44 8.18 0.1609 -17.77 0.33 12.45 8.92 O.1838 -19.93 0.30 11.25 9.64 0.2068 -22.07 0.26 9.87 10.35 0.2298 -24.18 0.22 8.34 11.03 0.2528 -26.26 0.18 6.71 11.70 0.2758 -28.30 0.13 5.01 12.35 0.2987 -30.35 0.09 3.29 13.02 0.3217 -32.46 0.04 1.57 13.73 0.3447 -34.52 -0.00 -0.16 14.43 0.3677 -36.53 -0.05 -1.88 15.14 0.3907 -38.49 -0.09 -3.59 15.85 0.4136 -40.38 -0.14 -5.26 16.55 4 0.4366 -42.21 -0.18 -6.88 17.26 0.4596 -44.20 -0.21 -0.12 18.12 0.4826 -46.11 -0.24 -9.27 18.99 0.5056 -47.95 -0.27 -10.33 19.87 0.5285 -49.69 -0.30 -11.28 20.76 0.5515 -51.34 -0.32 -12.13 21.66 0.5745 -52.89 -0.34 -12.85 22.57 0.5975 -54.44 -0.36 -13.52 23.52 0.6205 -55.93 -0.37 -14.10 24.50 I
p'c-C RACK VERSION 1.1 PAGE 2 0.6434 -57.32 -0.38 -14.58 25.48
'0.6664 -58.59 -0.39 -14.94 26.48 0.6894 -59.75 -0.40 -15.19 27.49 0.7124 -60.77 -0.40 -15.33 28.52 0.7354 -61.77 -0.41 -15.46 29.58 0.7583 -62.81 -0.41 -15.6S 30.71 0.7813 -63.73 -0.42 -15.S3 31.85 0.8043 -64.50 -0.42 -15.90 33.00 0.8273 -65.13 -0.42 -15.89 34.17 0.8503 -65.62 -0.42 -15.81 35.35 0.8732 -65.96 -0.41 -15.63 36.54 0.8962 -65.90 -0.37 -14.24 37.84 0.9192 -65.66 -0.34 -12.73 39.15 0.9422 -65.22- -0.29 -11.10 40.47 0.9652 -64.59 -0.25 -9.36 41.81 0.9881 -63.76 -0.20 -7.52 43.17 1.0111 -62.73 -0.15 -5.60 44.53 1.0341 -61.85 -0.12 -4.57 46.01 1.0571 -60.88 -0.10 -3.91 47.54 1.0801 -59.66 -0.08 -3.20 49.08 7 1.1030 -58.20 -0.07 -2.49 50.64 1.1260 -56.48 -0.05 -1.77 52.22 1.1490 -54.51 -0.03 -1.07 53.81 END OF pc-CRACK d
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B. Stress Data for Core Spray Nossle and Safe End B-1 i
REVISION STATUS sMt;T 23A4904 cont .N .,,,,, 2 ,,, m i S'EN ER AL f) ELECTRIC NUCLEAR ENERGY SU$lNESS OPERAT10NS oOCUMENT TITLE CORE SPRAY N0ZZLE TYPE LEGEND on OEsenEinow 0F Gnours , REACTOR SYSTEM - TY taPL ITEM NO, PRODUCT
SUMMARY
SECTION 7 C O DMH-1960 i 747 LED l \ l l
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muci.sansNa :v => - -. > SUSINESS OPERATIONS 8ENERALOitiernic mev 0 CERTIFICATION OF STRESS REPORT This certification with the documents listed below provides the basis for the Stress Report for a BWR Core Spray Nogale Replacement Safe-End and Thermal Sleeve. required by Paragraph MA-3350 of the ASME Boiler and Pressure vessel Code. Section III, 1980 Edition, with Addenda to and including Summer 1982. I certify that to the best of my knowledge and belief, the Stress Report for the Core Spray Nossle Replacement Safe-End and Thermal Sleeve is correct and complete, and in compliance with the requirements of the certified Design Specification. General Electric Document 23A4322. Revision 0, and Article NB-3000 of the ASME Boiler and Pressure Vessel Code, Section 111, 1980 Edition, with Addenda to and including Summer 1982. LISTED DOCUMENTS 4 Document Revision Type of Document Title Number Number Stress Report Reactor Vessel - Core Spray Nozzle 23A4904 0 l o .
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Certified by:9 L 2 P.E. Number: mO2SMS Reg: 6F red Professional $N ineer N: M.43:05
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23u m . ... n NUCLEAR ENERGY BUSINESS OPERATIONS GENER AL $ ELECTRIC REV O l 1 l l Cp Dr
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l l l0i y/ . 10 2 '5 1:.550 9.75- 12.12 5 S.00- 11.750 13.440 9.750 D1'EN5:ONS ARE IN INCHES i Figure / SATE END CEOMETRY
5 23A4904 ,,, ,,, 4, NUCLEAR ENERGY BUSINESS OPERATIONS GENER AL $ ELECTRib gy g PRIMARY STRESS ANALYSIS FOR SECTION C-C, DESIGN CONDITIONS COMPONENT MEMBRANE MEMBRANE PLUS BENDING b (in)* 6.717 6.717 a (in)* 5.778 5.778 e (in)* 6.248 - t (in) 0.939 0.939 A (in**2) 36.860 36.860 1 (in**3) 115.791 107.697 L (in) - SAFE-END 14.50 SLEEVE 20.56 Se (ksi) 7.692 8.364 7 Sr (ksi) 3.663 8.515 < Sx (ksi) -0.578 -1.250 TAUOz (ksi) O. O. TAUx0 (ksi) 0.199 0.199 PS1 (ksi) 7.702 8.652 PS2 (ksi) 3.653 8.226 PS3 (ksi) -0.578 -1.250 S113 = PS1 - PS3 (ksi) 8.280 < Se = 17.3 9.902 < 1.5*Se = 25.9 SI23 = PS2 - PS3 (ksi) 4.231 9.476 SI12 = PS1 - PS2 (ksi) 4.049 0.426
*These include corrosion allowance. fg = SSf-3%3 gu es c9BS 2. ,=re Adys+ s+resses Q o.cisg f avv o.c coun 4 0 11oyle J)v cdne.rs di CCe roue s
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2344904 . ... 34 NUCLEAR ENERGY BustNESS OPERATIONS GENER AL h ELECTRIC REV 0
, inner Element Outer Element Location Number Number 1 284 287 2 235 232 3 158 161 4 110 114 a
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p3nu na-n s 1 Figure 2 P+Q STRESS ANALYSIS LOCATIONS
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23A4904 .o.. , so N LEAR ENEOCY BUSINESS OPERATIONS GEN ER AL A O ELECTRIC #EV 0 . PRIMARY PLUS SECONDARY STRESS RANCES LIMITING - THERMAL LIMITING THERMAL BENDING LIMITING (2) (3) CASES RANGE TOTAL P+Q -Q b ALLOWABLE (1) STRESS STRESS Q , KSI b P+Q RANGE (3 S ) SECTION SURFACE STATE STATE RANGE KSI KSI* 1 2 KSI I STRTSHUT CSOP-1 65.331 82.383 17.052 51.75 1 0 STRTSHUT CSOP-1 72.428 116.164 48.638 51.75 1 STRTSHUT CSOP-2 54.377 83.710 29.333 51.75 2 O DSNNYDRO CSOP-2 46.446 57.024 12.778 51.75 I DSNHYDRO CSOP-3 20.793 53.386 32.593 51.75 3 0 DSNHYDRO CSOP-3 - 35.923 - 51.75 7 I STRTSHUT ZI.ROLOAD - 33.958 - 51.75 4 O STRTSHUT ZER0 LOAD - 29.707 - 51.75 I STRTSHUT CSOP-1 62.170 71.226 9.056 51.75 5 0 STRTSHUT CSOP-2 64.233 67.993 5.546 51.75 (1) I = Inside; O = Outside. . (2) In cases where (P+Q) meets the allowable, the value of Q and (P+Q-Q ) *** *
- b b listed. *
(3) S,value is at the design reactor temperature of 575'F. Sm ci = kpc = /t. 979 p:/ z. At';u!f .Tfrett b . 93T f G c co u n 'l- br
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e C. Ultrasonic Inspection Data O C-1
1 l 0 l l Summary The Vermont Yankee core spray nozzle to safe end welds were examined during the 1985-1986 refueling outage. Both welds were examined ultrasonically using m&9ual and P-scan techniques intended for use with multiple Inconel weld layers. P-scan showed three closely spaced indications in the circunferential direction (parallel with the weld longitudinal axis) on the NSB no:21e. The N5A nozzle showed no indications. Nanual axial examination of N5B showed seven axial indications, with a concentration of indications in the region showing the circumferential indications. N5A showed seven randomly spaced axial indications. Examination Techniaue Both nozzle to safe end welds were initially examined using nominal Code manual examination techniques employing refracted longitudinal beams. Using this method no indications were noted. However, because of the high " noise" level experienced during the examination overall confidence in the technique Was l oW. Utilizing the P-scan system with the same transducers used during the manual examination, several areas containing coherent reflectors were discriminated in the overall " noise" of the examination. Evaluation as to the nature of the reflectors was inconclusive. The relectors were located very close to the nominal alloy steel /Inconel interface, and the signal to noise ratio was quite low. C-2
- ., 6 4
In parallel with the core spray nozzle examinations, work was in progress t to optimize examination of the N2 nozzle to safe end welds. This effort had shown that a particular series of focused refracted longitudinal wave probes were effective in examining multiple stainless steel weld butters and clads. Though not directly proven for the Vermont Yankee configuration these transducers had also been utilized for Inconel weld examinations at other reactors. The large " footprint" of these transducers (2.5" x 2.5') prohibited scanning normal to the weld. By machining the transducer contact surf aces it was possiole to scan parallel with the weld. Manual examination with these transducers showed the axial indications discussed in the Summary. C-3
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