ML20147G337
| ML20147G337 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 02/29/1988 |
| From: | Hoffman J VERMONT YANKEE NUCLEAR POWER CORP., YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20147G315 | List: |
| References | |
| NUDOCS 8803080196 | |
| Download: ML20147G337 (74) | |
Text
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Ve mont Yankee Nuclear Power Station Justification for Long Term operation for l Vermont Yankee Core Spray Hozzle Weld overlays
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Vermont Yankee Nuclear Power Corporation [ l Joww R. HoFFM AN. P.E. YANKEE ATCHIC ELECTRIC CCMPANY i l 3 ... _ .... .... . Framlagnam, toassachusetts 01701 0803080196 880301 PDR ADOCK 05000271 P PDR
TABLE OF CONTENTS
. 1. Summary................................................................ 1-1
- 2. Background ............................................................ 2-1
- 3. Weld Overlay Design.................................................... 3-1
- 4. Long Term Operation with Weld overlays................................. 4-1 4.1. As-built Data..................................................... 4-1 4.2. Design Stress Data................................................ 4-1 4.3. Flav Growth Studies............................................... 4-2
- 5. 1987 Refueling Outage Inspections...................................... 5-1
- 6. Evaluation of Lov Alloy Steel Stress Corrosion Cracking................ 6-1 7 . Sumary o f Conservat isms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
- 8. Conclusion............................................................. 8-1
- 9. References............................................................. 9-1 Appendices A. Supporting Data for F1gures.............................................A-1 B. Stress Data for Core Spray Nozzle and Safe End. . . . . . . . . . . . . . . . . . . . . . . . . .B-1 C. Method of Analysis for Weld Overlay Stresses............................C-1 D. Benchmarking of SUPERSAP Computer Program. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-1 E. Results of 1987 Weld Overlay Inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E-1 F. Development and Application of Weld Overlays............................F-1 1
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LIST OF FIGURES 2-1: Reactor Pressure vessel............................................... 2-1 2-2: Core Spray Safe End and Nozzle........................................ 2-2 2-3: Safe End Weld Detail.................................................. 2-3 3-1: Completed Weld Overlay................................................ 3-2 4-1: Core Spray Safe End Axial Stress Profile.............................. 4-4 4-2: Core Spray Safe End Axial Stress Intensity Profile.................... 4-5 4-3: Core Spray Nozzle Weld Overlay Stress Distribution. . . . . . . . . . . . . . . . . . . . 4-6 6-1: Crack Profile in Lov Alloy Steel BWR Nozzle........................... 6-4 C-1: Safe End, Nozzle and Reactor Pressure Vessel Finite Element Model......C-4 C-2: Inlet Nozzle - Principal (Hoop) Stress - 1000 psi Pressure.............C-5 C-3: Pressure Case, 0 = 00..................................................C-6 C-4: Vermont Yankee Core Spray Nozzle - Hoop Stress Contours................C-7 C-5: Vermont Yankee Core Spray Nozzle Weld Overlay Model Detail.............C-8 C-6: Vermont Yankee Core Spray Nozzle Weld Ove'. lay - Compressive Stress.....C-9 C-7: Vermont Yankee Core Spray Nozzle - Maximum Principal Stress...........C-10 C-8: Vermont Yankee Core Spray Nozzle - One-half Nominal Shrinkage.........C-11 F-1: Base Metal Hardness Profiles Af ter Overlay Welding. . . . . . . . . . . . . . . . . . . . .F-5 F-2: Weld Layer Chemistry - SA 508 Base Metal and Inconel 82 Weld Metal.....F-6 F-3: 'Ihermal Profiles Under overlay with and without Water at ID Surface....F-7 11
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. j Justification for Long Tern Operation - for : '- Vermont Yabl.eelCbre Spray Nozzle Weld OV rlayo \
- 1. Summary In May 1986 Vermont Yankee applied veld overlays to the safe end to nozzle velds on the two core spray nozzles on the reactor pressure vessel.1'* In J5nuary 1987 Vermont Yankee submitted an
( engineering report to the USNRC demonstrating that at least two cycles of operation with the overlays was justified.' The USNRC approved operation with the overlays through cycle 13 (scheduled to end in February 1989) providing satisfacrery results were obt'4neda from ultrasonic examinations conducted during the cycle - 12 refueling outage.**** This report-discusses the factors related to long term operation of the veld overlays and demonstrates that long term operation in accordance with the guidelines of NUREG-0313 Rev. 2 s
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is justified." Flav growth evaluations were performed using the guidelines 3 provided in NUREG-0313 Pev 2. A flav just below the threshold of detectability was assumed and no credit was taken for any residual stress benefit from the veld overlay. Even using this very conservative approach an unlimited serv'ce i life was predicted.
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The recent lov alloy steel nozzle cracking incidents have been evaluated with respect to their impact on the use cf veld overlays. For the geometry and applied stress conditions of the Vermont Yankee core spray nozzles the possibility of lov alloy steel stress corrosion cracking provides no additional structural integrity concerns. l 1-1 I I
\ 4't. Background
- The two core spray nozzles (called the N5 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 mata with the 8' inch core spray piping, as shown in Figure-2-2.
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Th3 nozzle ic fcbriccted froc.SA508 CL2 lov alloy otool; tho safe end is fabricated from SB166 Alloy 600 (Inconel 600). Both I' components are forgings. The nozzic is clad with Incottel 182 weld metal to allow for velding the safe end to the nozzle without having to perform a subsequent post veld beat treatment.
,- The safe end is velded to the nozzle with Inconel 82 veld metal.
The details of the veld joint are shown in Figute 2-1. 1 2 4
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l, Gn.rgan., llli'!. ,w ., . f 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 veld metal on the face of the nozzle. Since Inconel 182 has been shown to be susceptible to IGSCC the
$oints were considered flawed and a veld overlay was applied.
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- 3. Weld overlay Design
- The veld overlay was designed in accordance with the requirements of the ASME Code, Section XI. The design stress information was taken from the original stre's report for the reactor pressure vessel.*
Because the SA508 CL2 nozzle material is a hardenable alloy specialized velding procedures were developed to allow velding without a subsequent post veld heat treatment. The procedures were based on the concepts discussed in References 7 and 8. Mockup testing was performed to develop site specific welding procedures. Qualification testing was performed to demonstrate that the desired material toughness recovery was achieved. The approach was to apply a three layer Inconel veld overlay as a butter-temper process to achieve the desired post veld heat treatment effect as well as to provide a minimum 0.125 inch thick weld deposit so that subsequent velding could be performed without any special controls relative to material embrittlement.* Based on the design stress conditions a veld overlay thickness of 0.41 inches was required; allowing for the 0.125 butter-temper layers, a total ow rlay thickness of 0.535 inches was required. The finished veld overlay is shown in Figure 3-1. A full discussion on the development and application of the i weld overlays is contained in Appendix F. 3-1
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Wl@ 4AUGE WW21< MMOJ54C5J _ di G WELD GAUGE DATA Location Initial Post Weld 6 0 8.4G2. 8.4%7 , oIS 90 g la;c 8.347 . m.4 180 g, ~42 4 B,3OJL ..ogu 210 Re A13 ' B. SIS -
+ ,003 DIMENSIONAL DATA Incation A B C D E F 0 L 22D e18i L El3 11AO 4 t 5I d. . VJE 90 EAn n '1Al LtM 1.149 2 t> 8e L 312'-
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- 4. Lcng Tara Op3rcticn with Wold Ovoricy3
, ALARA and economic considerations make it desirable to qualify the core spray nozzle veld overlays for long term operation.
In order to demonstrate that long term operation is justified in accordance with USNRC guidelines, the veld overlays have been re-evaluated using as-built data and updated design information. 4.1. As-built Data The actual veld 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 lovest 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.* Since this analysis represents current design j methodology an6 analytical approaches the stresses from this i l analysis were used in re-evaluating the as-installed weld l l overlays. Us)ng the revised stress information a minimum overlay 1* thickness of 0.314 inches was determined to be required.51 l 4-1 i
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4.3. Flav Jrowth Studies ; Flav growth studies ** vere performed to determine the time period available before the original flav vould grow deep enough to penetrate into the minimum required 0.314 inch overlay. The original flav size was judged to be-in the range of 30 to 35 percent of wall thickness; for conservatism, a flav 75 percent of the original safe end vall thickness was assumed. This selection was based on the fact that the ultrasonic examination technique used on the overlays is demonstrated capable of detecting a flav in the upper 25 percent of the original safe end. The first evaluation was performed using the criteria from No credit was taken for any residual stress benefit
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NUREG-0313.* from the veld overlay. A residual stress pattern from NUREG-0313 was corbined with the applied primary membrane, primary bending and secondary thermal stresses from the stress report
- to create the applied stress field. The applied stresses were adjusted for the combined thickness of the safe end and overlay, as permitted by NUREG-0313 Rev 2 and discussed in Reference 16.
Figure 4-1 shovs the net stress profile through the safe end in the axial direction. Figure 4-2 shows the net stress intensity profile resulting from that stress field. As can be seen due to the negative stress intensity region at the flav tip no flav growth beyond 75 percent deep is predicted. A flav shallover than 75 percent could propagate, but it would arrest. The second evaluation considered the effect of the local veld shrinkage caused by the veld overlay. A two-dimensional axisymmetric model of the reactor pressure vessel and core spray i nozcle was developed. 4-2 ,
The axial shrinkage obtained from the co-built dato veo . applied to the model by adjusting the nodal temperatures. A discussion of the methods of analysis and the benchmarking of the computer program is contained in Appendices C and D, respectively. As can be seen from Figure 4-3, approximately 90 percent of the original safe end and nozzle ur. der the veld overlay is in compression. This result is consistent with other studies on veld overlay induced stresses **. The analysis considered the normal rcactor pressure and applied loads, so the indicated stress profile is the net stress profile. Since the stress profile is compressive, no flav growth would be predicted; this conclusion is consistent with laborator'y and field observations on flawed pipe overlays. In summary, using the USNRC evaluation criteria provided in NUREG-0313 Rev 2, taking no credit for the veld overlay induced stresses, it has been demonstrated that no flav growth is pred'cted beyond 75 percent of the original vall thickness. In addition, using actual data from the veld overlay application, it has been shown that a significant compressive stress field is developed under the veld overlay. Thus, even if the NUREG-0313 Rev 2 residual stress field is neglected there is l still no predicted flav growth beyond 75 percent of original vall thickness. I 4-3
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4 b ~_ \ ( n 40.00 - - 3 Vermont Yankee Core Spray Safe End Net Thru-wall Stress Profile
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- 5. 1987 Refueling Outage Inspection 9
- During the 1987 refueling outage, following cycle 12, non-destructive examinations were conducted on the veld overlay, underlying basemetal and nozzle basemetal adjacent to the overlay. Liquid penetrant examination was performed on the overlay surface, the overlay end tapers and the nozzle and safe end base metal adjacent to the overlay. Ultrasonic examinations were conducted using techniques based upon the EPRI weld overlay inspection program with modifications demonstrated and qualified on the Vermont Yankee veld overlay nozzle mockup. The examinations were conducted by Level II and Level III personnel qualified in accordance with SNT-TC-AA and the EPRI veld overlay flav examination qualification program. No relevant indications were detected.
Details of the inspection techniques were submitted to the USNRC.1' A copy of the letter is included ts Appendix E to this report. f 5-1
- 6. Evaluation of Low Alloy St001 StrGOD C3rrcsiCn CICcking
- In 1987, stress corrosion cracking was detected in the SA 508 lov alloy steel portion of a reactor recirculation inlet of an overseas boiling water reactor. The cracking was initiated in the Inconel 182 veld butter and extended axially into the nozzle approximately % inch, as shown in Figure 6-1.
In January 1988 cracking was reported in a recirculation inlet nozzle at a domestic boiling water reactor (Brunswick 2). The cracking initiated in the Inconel 182 cladding at the inside diameter of the nozzle and extended in a circumferential direction and through vall into the SA 508 nozzle base metal. The significance of these discoveries will be discussed and their impact on the use of veld overlays on lov alloy steel nozzles will be evaluated. The existence of the foreign reactor flav and the depth of penetration is consistent with the stress field and corrosion behavior of a field velded nozzle to safe end butt veld.2d For a non-overlayed nozzle the maximum depth of penetration would be expected to be less than M inch. The presence of a veld overlay would not increase the propensity to cracking or the flav growth rate; in fact, the compressive stress field would tend to inhibit flav growth. ! The recirculation system at Brunswick 2 has a significant number of weld overlays. The normal operating stresses combined with the shrinkage stresses resulting from the veld overlays on i the pipe velds are considered sufficient to cause stress corrosion cracking in Inconel 182 and SA 5082', so the discovery of the flav is not considered to be causad-by a new phenomena. l i 6-1 l l
Ultrasonic oxGoinctiono conductcd at Varcont YonkGs in 1986
- prior to the application of the veld overlays revealed no cracking in the. nozzle or safe end basemetal; as stated in Section 5 the examinations in 1987 also revealed no evidence of basemetal cracking.
To evaluate the consequences of potential lov alloy steel stress corrosion cracking in the core spray nozzles the following conservative evaluation was conducted:
- 1. assume an infinitely long longitudinal flav
- 2. assume that the hoop stress equals the primary membrane plus bending stress
- 3. assume that the nozzle is not veld overlayed.
Using these assumptions, an 80 percent deep flav vould have a stress intensity factor of approximately 72 ksi-rin. A flav this deep would be detectable by ultrasonic examination even through the veld overlay. f From Appendix A to ASME Section XI, this corresponds to a ! metal temperature 30F above RTwoe. The nozzle material certification shows that the Charpy V-notch impact energy is equal or greater than 120 ft-lbs at 40F. This infers an RTwoe vell below 40F. Thus, at ambient conditions the required toughness would be achieved. Since the RTwo, of the reactor vessel beltline is governing for Vermont Yankee (currently at an adjusted RTwo, of 69F)**, the structural integrity of the nozzle is not threatened. In conclusion, lov alloy steel stress corrosion cracking provides no special problems relative to veld overlays. Weld overlays vill not initiate or accelerate flaw growth in the 6-2
nozzle welds to which they are applied; the realistic conclusion is that the overlay vill suppress any flaw growth. While it is true that a weld overlay makes volumetric inspection of the overlayed nozzle more difficult, flav detection
.1:s assured long before the structural integrity of the nozzle would be affected. Thus, it is concluded that the nozzle cracking incidents provide no new concerns relative to the suitability of weld overlass as a long term stress corrosion cracking mitigation measure.
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- 7. Summary of conservatisms
. The results presented above demonstrate that long term 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 ASME Section XI flawed pipe evaluation process
$s conservative.
- 2. Ctde minimum values are used for required material pr operties .
- 3. Lounding loads are used for the stress analysis.
- 4. The USNRC residual stress profile is a conservative approximation (i.e. underestimates) the probable as-velded compressive residual stress profile.
- 5. The overlay thickness used in the evaluation is the minimum value of 16 readings.
- 6. The flaw growth calculations assumed a full 360 degree flaw, even though the actual flav was considerably smaller.
- 7. The flav depth used in the studies is more than two times larger than the best estimate flav size.
- 8. Unlike overlays on stainless steel pipe, the overlay velding 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.
- 9. The method used to assess the compressive stress due to the veld overlay significantly underpredicts the actual magnitude of the compressive stresses.
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- 8. Conclusion It has been demonstrated that continued operation with veld overlays on the core spray nozzles beyond cycle 13 vill not infringe on the code required structural integrity of the veld j overlays or the reactor pressure vessel.
The evaluation shows that unlimited life of the overlays is to be expected. Confirmation of that evaluation vill be obtained by performing periodic ultrasonic examination of the veld overlays during refueling outages in accordance with NUREG-0313 Rev 2 requirements. i s I J J 1 8-1 l
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- 9. Roforcnc00 ;
- 1. Letter from VYNPC to USNRC, dated May 5, 1986 (FVY 86 36).
- 2. Letter from USNRC to VYNPC, dated June 23, 1986 (NVY 86-113).
- 3. Letter from VYNPC to USNRC, dated January 12, 1987 (FVY 87-07). ,
- 4. Letter from USNRC to VYNPC, dated May 28, 1987 (NVY 87-81). >
- 5. NUREG-0313 Revision 2, issued January 25, 1988.
- 6. Chicago Bridge and Iron Stress Report 9-6202-1, Section I-S-7, 7 August 1969.
- 7. EPRI Report NP-3614, "Repair Welding of Heavy Section Steel Components in LWRs", July, 1984.
- 8. ASME Code Case N-432, "Repair Welding Using Automatic or Machine Gas-Tungsten Arc Welding (GTAW) Temperbead Technique, Section XI, Division 1, February 20, 1986.
9._toField Aeolication of a Non-Post Weld Heat Treat Weld Overlav an Allov Steel Reactor Pressure Vessel Nozzle; Hoffman, l Mullins, Willens, Darby; Presented at EPRI Seminar on Repair Welding Alternatives for Nuclear Power Plant Components, Charlotte, NC, March 11, 1987.
- 10. General Electric Company Report 23A4904, "Core Spray Nozzle Stress Report", December 13, 1985.
- 11. ASME Boiler and Pressure Vessel Code, Section XI, Subsection IWB-3641, 1983 Edition thru Winter 1986 Addenda.
- 12. EPRI Interim Report for Project EPRI-1566-2. ;
- 13. Letter from VYNPC to USNRC, dated October 20, 1987 (FVY 87-100)
- 14. General Electric Company Presentation to USNRC, Bethesda ,
i Maryland, September 22, 1987. ,
- 15. pc-CRACK User's Manual, Version 1.2, Structural Integrity ,
Associates, San Jose, CA., March 1987.
- 16. Scott Paul M., "Assessment of Design Basis for Load-Carrying Capacity of Weld-Overlay Repairs", NUREG/CR-4877, April 1987.
- 17. Meeting between Carolina Power & Light and USNRC at Bethesda, Maryland, January 27, 1988. ,
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- 18. Vermont Yankee Technical Specifications. ;
I i 9-1 l
4 A. Supporting Data for Figures A-1
I to pc-CRACK (C) COPYRIGHT 1983, 1937 STRUCTURAL INTEGRITY ASSOCIATES, INC.
- SAN JOSE, CA (408)978-8200 VERSION 1.2 STRUCTURAL REINFORCEMENT SIZING EVALUATION STRUCTURAL REINFORCEMENT SIZING FOR CIRCUMF. CRACK, WROUGHT / CAST STAINLESS VERMONT' YANKEE CORE SPRAY SAFE END WELD OVERLAY WALL THICKNESS = 0.9140 MEMBRANE STRESS = 8507.0000 BENDING STRESS = 1666.0000 STRESS RATIO =- 0.4366 ALLOWABLE STRESS =233OO.OOOO FLOW STREES=69900.OOOO L/ CIRCUM O.00 0.10 0.20 0.30 0.40 0.50 FINAL A/T O.7500 0.7500 0.7500 0.7500 0.7500 0.7441 REINFOPCEMENT THICK. O.3047 0.3047 0.3047 0.3047 0.3047 0.3143 END OF pc-CRACK
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NRC NUREG-0313 Rev 2 Fracture Mechanics Spreadsheet l Normalized Actual Depth Stress j Thru-wall ' Position Residual Stress O.OO 1.00000 0.00 38.00 0.05 0.67614 0.05 25.69 0.10 0.39519 0.09 15.02 0.15 0.15631 0.14 5.94 0.20 -0.04160 0.18 -1.58 0.25 -0.19998 0.23 -7.60 0.30 -0.32055 0.27 -12.18 0.35 -0.40534 0,32 -15.40 0.40 -0.45669 0.37 -17.35 0.45 -0.47724 0.41 -18.14 0.50 -0.46994 0.46 -17.86 0.55 -0.43803 0.50 -16.64 0.60 -0.38506 0.55 -14.63 0.65 -0.31489 0.59 -11.97 0.70 -0.23169 0.64 -0.80 0.75 -0.13992 0.69 -5.32 0.80 -0.04434 0.73 -1.68 0.85 0.04997 0.78 1.90 0.90 0.13764 0.82 5.23 0.95 0.21297 0.87 0.09 1.00 0.27000 0.91 10.26 I i I i l l l L
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- Als 'NRC-NUREG-0313 Rev 2 Fracture Mechanics Spreadsheet A3: 'Thru-wall C3: ' Normalized A4: 'FOsition !
C4: ' Residual Stress A6: (F2) O C6: (F5) SSUM(1+(-6.91*A6)+(8.687*A6^2)+(-0.48*A6^3)+(-2.027*A6^4)) ) A7: (F2) 0.05 C7: (F5) eSUM(1+(-6.91*A7)+(8.687*A7^2)+(-0.48*A7^3)+(-2.027*A7^4)) j A8: (F2) 0.1 CB: (F5) GSUM(1+(-6.91*A8)+(8.687*AB^2)+(-0.48*AB^3)+(-2.027*A8^4)) A9: (F2) 0.15 C9: (F5) OSUM(1+(-6.91*A9)+(8.687*A9^2)+(-0.48*A9^3)+(-2.027*A9^4)) A10: (F2) 0.2 C10: (F5) eSUM(1+(-6.91*A10)+(8.687*A10^2)+(-0.48*A10^3)+(-2.027*A10^4)) A11: (F2) 0.25 C11: (F5) eSUM(1+(-6.91*A11)+(8.687*A11^2)+(-0.48*A11^3)+(-2.027*A11^4)) A12: (F2) 0.3 C12: (F5) 95UM(1+(-6.91*A12)+(8.687*A12^2)+(-0.48*A12^3)+(-2.027*A12^4)) A13: (F2) 0.35 C13: (F5) GSUM(1+(-6.91*A13)+(8.687*A13^2)+(-0.48*A13^3)+(-2.027*A13^4)) A14: (F2) 0.4 C14: (F5) eSUM(1+(-6.91*a14)+(8.687*A14^2)+(-0.48*A14^3)+(-2.027*A14^4)) A15: (F2) 0.45 C15: (F5) GSUM(1+(-6.91*A15)+(8.687*A15^2)+(-0.48*A15^3)+(-2.027*A15^4)) A16: (F2) 0.5 C16: (F5) eSUM(1+(-6.91*A16)+(8.687*A16^2)+(-0.48*A16^3)+(-2.027*A16^4)) A17: (F2) 0.55 C17: (F5) eSUM(1+(-6.91*A17)+(0.687*A17^2)+(-0.48*A17^3)+(-2.027*A17^4)) A18: (F2) 0.6 C18: (F5) eSUM(1+(-6.91*A18)+(8.687*A18^2)+(-0.48*A18^3)+(-2.027*A18^4)) A19: (F2) 0.65 C19: (F5) GSUM(1+(-6.91*A19)+(8.687*A19^2)+(-0.48*A19^3)+(-2.027*A19^4)) A20: (F2) 0.7 C20: (F5) eSUM(1+(-6.91*A20)+(8.687*A20^2)+(-0.48*A20^3)+(-2.027*A20^4)) A21: (F2) 0.75 C21: (F5) eSUM(1+(-6.91*A21)+(8.687*A21^2)+(-0.48*A21^3)+(-2.027*A21^4)) A22: (F2) 0.8 C22: (F5) eSUM(1+(-6.91*A22)+(8.687*A22^2)+(-0.48*A22^3)+(-2.027*A22^4)) A23: (F2) 0.85 C23: (F5) eSUM(1+(-6.91*A23)+(8.687*A23^2)+(-0.48*A23^3)+(-2.027*A23^4)) A24: (F2) 0.9 C24: (F5) SSUM(1+(-6.91*A24)+(8.687*A24^2)+(-0.48*A24^3)+(-2.027*A24^4)) A25: (F2) 0.95 C25: (F5) SSUM(1+(-6.91*A25)+(8.687*A25^2)+(-0.48*A25^3)+(-2.027*A25^4)) . A26: (F2) 1 C26: (F5) GSUM(1+(-6.91*A26)+(8.687*A26^2)+(-0.48*A26^3)+(-2.027*A26^4)) i t
to pc-CRACK (C) COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. SAN JOSE, CA (408)978-8200 VERSION 1.2 LEAST SQUARE CURVE FIT OF STRESS PROFILE CURVE FIT FOR NUREG-0313 RESIDUAL STRESS T!RM COEFFICIENT C0 3.9137E+01 C1 -3.115E+02 C2 5.1432E+02 C3 -2.265E+02 COEFFICIENT OF DETERHINATION R^2= 0.9989 CORRELATION COEFFICIENT = 0.9978 X VALUE Y VALUE Y CALC DIFF 0.0000E+00 3.8000E+01 3.9137E+01 -1.137E+00 5.0000E-02 2.5690E+01 2.4820E+01 8.7010E-01 9.0000E-02 1.5020E+01 1.5103E+01 -8.335E-02 1.4000E-01 5.9400E+00 4.9867E+00 9.5329E-01 1.8000E-01 -1.580E+00 -1.589E+00 9.3579E-03 2.3000E-01 -7.600E+00 -8.056E+00 4.5559E-01 2.7000E-01 -1.218E+01 -1.193E+01 -2.485E-01 3.2000E-01 -1.540E+01 -1.530E+01 -1.022E-01 3.7000E-01 -1.735E+01 -1.718E+01 -1.704E-01 4.1000E-01 -1.814E+01 -1.773E+01 -4.095E-01 4.6000E-01 -1.786E+01 -1.737E+01 -4.914E-01 5.0000E-01 -1.664E+01 -1.634E+01 -2.954E-01 5.5000E-01 -1.463E+01 -1.429E+01 -3.407E-01 5.9000E-01 -1.197E+01 -1.213E+01 1.6077E-01 6.4000E-01 -8.800E+00 -8.932E+00 1.3249E-01 6.9000E-01 -5.320E+00 -5.337E+00 1.7057E-02 7.3000E-01 -1.680E+00 -2.289E+00 6.0892E-01 7.8000E-01 1.9000E+00 1.5933E+00 3.0672E-01 8.2000E-01 5.2300E+00 4.6507E+00 5.7934E-01 8.7000E-01 8.0900E+00 8.2692E+00 -1.792E-01 9.1000E-01 1.0260E+01 1.0896E+01 -6.355E-01 END OF pc-CRACK
1 , to pc-CRACK > (C) COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. SAN JOSE, CA (408)978-8200 VERSION 1.2 LINEAR ELASTIC FRACTURE NECHANIC3 EVALUATION VY CORE SPRAY SAFE END K VS A CRACK NODEL:CIRCUNFERENTIAL CRACK IN CYLINDER (T/R=0.2) CALL THICKNESS = 1.4540 STRESS COE7FICIENTS CASE ID CO C1 C2 C3
- APPLIED 9.9020 0.0000 0.0000 0.0000 NUREG 39.1374 -311.4989 514.3236 -226.5071 NETSTRS 45.3620 -311.4989 514.3236 -226.5071 CRACK ---------------STRESS INTENSITY FACTOR---------
DEPTH CASE CASE CASE APPLIED MUREG NETSTRS 0.0228 2.928 10.379 12.220 0.0456 4.158 13.146 15.760 0.0684 5.114 14.322 17.537 0.0912 5.930 14.595 18.323 0.1140 6.658 14.266 18.451 0.1368 7.324 13.506 18.110 0.1596 7.971 12.485 17.496 0.1824 8.604 11.255 16.663 0.2052 9.213 9.840 15.631 l 0.2280 9.803 8.286 14.449 l 0.2508 10.376 6.631 13.154
- 0.2736 10.940 4.904 11.781 1 0.2964 11.510 3.178 10.413 l
0.3192 12.131 1.570 9.197 0.3420 12.750 -0.034 7.981 l 0.3648 13.368 -1,619 6.785 O.3876 13.985 -3.168 5.624 0.4104 14.602 -4.668 4.511 0.4332 15.220 -6.107 3.461 0.4560 15.886 -7.360 2.627 0.4T88 16.564 -8.496 1.917 l 0.5016 17.246 -9.520 1.321 0.5244 17.933 -10.421 0.852
- 0.5472 18.624 -11.190 0.517 1 0.5700 19.320 -11.817 0.328 1 0.5928 20.041 -12.523 0.076 0.6156 20.790 -13.373 -0.304 0.6384 21.545 -14.154 -0.611 l
l l \
VERSION 1.2' PAGE 2 pc-CRACK 0.6612 22.307 -14.868 -0.846 0.6840 23.075 -15.518 - 1.012 0.7068 23.850 -16.106 -1.113 0.7296 24.642 -16.564 - 1.073 i 0.7524 25.525 -16.331 -0.285 O.7752 26.418 -15.948 0.660 0.7980 27.320 -15.412 1.762 1 0.8208 28.231 -14.726 3.021 , 0.8436 29.152 -13.890 4.435 ! 0.8664 30.081 -12.907 6.003 0.8892 31.076 11.708 7.827 0.9120 32.103 -1C.337 9.844 0.9348 33.141 -8.820 12.013 0.9576 34.189 -7.165 14.327 0.9304 35.247 -5.379 16.779 1.0032 36.316 -3.471 19.359 1.0260 37.436 -1.847 21.686 1.0488 38.639 -0.904 23.385 1.0716 39.854 0.009 25.062 1.0944 41.082 0.871 26.696 1.1172 42.322 1.661 28.266 1.1400 43.575 2.356 29.748 END OF pc-CRACK I i - - - - ~ , . - - , , , - - - . - - , - - - - - - - , . - - - - , , - r.- -, - - - - - - - - - , , , . , .-----v- w, - - , e-- .
to L pc-CRACK (C) COPYRIGHT 1984, 1937 STRUCTURAL INTEGRITY ASSOCIATES, INC.
. SAN JOSE,lCA (408)978-8200 VERSION 1.2 LINEAR ELASTIC FRACTURE MECHANICS EVALUATION VERMONT YANKEE CORE SPRAY N0ZZLE (ASSUME NO OVERLAY)
CRACK MODEL LONGITUDINAL CRACK IN CYLINDER (T/R=0.1) WALL THICKNESS = 0.9140 STRESS COEFFICIENTS CASE ID CO C1 C2 C3 MYSURGE 16.7500 0.0000 0.0000 0.0000 NRC 38.8020 -309.6470 511.6590 -225.4730 NRCRESID .1.0211 -8.1486 13.4647 -5.9.335 APPLIED 9.9020 0.0000 0.0000 0.0000 CRACK ---------------STRESS INTENSITY FACTOR---------------- DEPTH CAS'd CASE CASE CASE MYSURGE NRC NRCRESID APPLIED 0.0146 3.818 8.233 0.217 2.257 0.0292 5.519 11.070 0.291 3.263 0.0439 6.906 12.875 0.339 4.083 0.0585 8.143 14.102 0.371 4.814 . 0.0731 9.293 14.937 0.393 5.494 0.0877 10.387 15.482 0.407 6.140 0.1024 11.489 15.853 0.417 6.792 ; 0.1170 12.588 16.050 0.422 7.442 - 0.1316 13.676 16.'083 0.423 8.085 l 0.1462 14.757 15.974 0.420 8.724 0.1609 15.835 15.741 0.414 9.361 ' 0.1755 16.914 15.398 0.405 9.999 O.1901 18.036 14.997 0.395 10.662 f 0.2047 19.209 14.547 0.303 11.356 4 0.2194 20.393 14.019 0.369 12.056 . 0.2340 21.588 13.420 0.353 12.762 0.2486 22.795 12.762 0.336 13.475 l 0.2632 24.014 12.051 0.317 14.196 l 0.2779 25.310 11.309 0.298 14.962 > 0.2925 26.823 10.535 0.277 15.857 l 0.3071 28.362 9.688 0.255 16.767 0.3217 29.927 8.773 0.231 17.692 0.3364 31.517 7.795 0.205 18.632 0.3510 33.132 6.762 0.178 19.586 . O.3656 34.771 5.679 0.149 20.556 0.3602 36.743 4.543 0.120, 21.721 , O.3948 38.750 3.314 0.087 22.908 ! i i I i
~- - - , - -
- , - . - ---,---,,n.., .,--,.-r, ,, , , . . . - - - ,, - - - - - , - . ,
pr.-CRACK VERSIDN 1.2 PAGE 2
- 0.4095 40.703 1.994 0.052 24.115 0.4241 42.870 0.537 0.015 25.343 0.4387 44.981 -0.904 -0.024 26.591
- 0.4533 47.125 -2.478 -0.065 27.859 0.4680 49.809 -3.325 -0.088 29.445 0.4826 52.713 -3.945 -0.104 31.162 0.4972 55.670 -4.595 -0.121 32.910 0.5118 58.678 -5.271 -0.139 34.688 0.5265 61.737 -5.967 -0.157 36.497 0.5411 64.846 -6.677 -0.176 38.334 0.5557 68.262 -7.010 -0.184 40.354 0.5703 71.996 -6.919 -0.182 42.561 0.5850 '75.790 -6.768 -0.178 44.804 0.5996 79.645 -6.547 -0.172 47.083 0.6142 83.559 -6.246 -0.164 49.397 0.6288 87.531 -5.853 -0.154 51.745 0s6435 91.699 -5.556 -0.146 54.209 0.6581 96.346 -5.779 -0.152 56.956 0.6727 101.061 -5.944 -0.156 59.744 0.6873 105.844 -6.039 -0.159 62.571 0.7020 110.693 -6.053 -0.159 65.438 0.7166 115.608 -5.978 -0.157 68.343 0.7312 120.G87 -5.802 -0.153 71.287 END OF pc-CRACK I
- - - - - .. . . . . = . . . -
l l 220 u l 200 - 180 - g 160 - K
; 140 - Ic u 120 - Ia E
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y 60 - t b 40 - 2 u. 20 - o
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-100 -50 0 +50 +100 +150 +200 (T-RTNDT), ( F)
Figure 2.4 - Lower Bound Toughness Curves From Tests of SA-5338-1, SA-508-2, and SA-508-3 Steel (Section XI, Fig. A-4200-1).
.. . , m_ _ _ _ .-
I to
. pc-CRACK (C) COPYRIGHT 1024, 1937 STRUCTURAL INTEGRITY ASSOCIATES, INC.
- SAN JOSE, CA (408)978-8200 VERSION 1.2 STRUCTURAL REINFORCEMENT SIZING EVALUATION STRUCTURAL REINFORCEMENT SIZING FOR CIRCUMF. CRACK, WROUGHT / CAST STAINLESS COMPARISON WITH USER'S MANUAL PROBLEM FOR BENCHMARKING WALL THICKNESS = 0.6100 MEMBRANE STRESS = 6.4S70 BENDING STRESS = 13.1450 STRESS RATIO = 1.1582 ALLOWABLE STRESS = 16.9500 FLOW STRESS = 50.8500 L/ CIRCUM 0.00 0.10 0.20 0.30 0.40 0.50 FINAL A/T 0.7500 0.7500 0.7500 0.7383 0.6846 0.5889 REINFORCEMENT THICK. 0.2033 0.2033 0.2033 0.2162 0.2811 0.4259 END OF pc-CRACK I
b
Table I-4 OUTPUT. TEX Wednesday, April 22, 1987 Parmt o ta pc-CRACK (C) COPYRIGHT 1984, 1987 STRUCTURAL INTEGRITY ASSOCIATES, INC. SAN JOSE, CA (408)978-8200 VERSION 1.2 STRUCTURAL REINFORCEMENT SIZING EVALUATION STRUCTURAL REINFORCEMENT SIZING FOR CIRCUHF. CRACK, WROUGHT / CAST STAINL ESS SAMPLE PROBLEM I WALL TEICKNESS= 0.6100 MEMBPJulE STRESS: 6.4870 ' BENDING STRESS: 13.1450 STRESS RATIO: 1.1582 ALLOWABLE STRESS: 16.9500 ' FLOW STRESS = 50.8500 L/ CIRCUM 0.00 0.10 0.20 0.30 0.40 0.50 FINAL A/T 0.7500 0.7500 0.7500 0.7383 0.6848 0.5889 REINFORCEMENT THICK. 0.2033 0.2033 0.2033 0.2182 0.2811 0.4259 i 4 t i I-17 l
B. Stress Data for Core Spray Nozzle and Safe End 9" B-1
REVCION STATUS SHSST 23A4904
,GENERALOiticiaic - -" ' -- 2 l
I NVCLE AR ENERGY SUSINESS OPER ATIONS 1 oocustNT TITLE CORE SPRAY N0ZZLE l l STRESS REPORT I Leo &No on 06acahisow or omoves pup REACTOR SYSTDI - YT upg gygg go, _ PRODUCT SUMKARY SECTION 7 MEVISIONS lC 0 DMH-1960 i k l l l l l l 74? LED l I l
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22^0' 2 wuct ARaNE ov GENERA V L P) E LECTRIC = =o. BUSINESS OPERATIONS Egv g CERTIFICATION OF STRESS REPORT This certification with the documents listed below provides the basis for the Stress Report for a BWR Core Spray Nozzle Replacement Safe-End and Thermal Sleeve, required by Paragraph NA-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 Nozzle 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 III, 1980 Edition, with Addenda to and including Summer 1982. LISTED DOCUMENTS Document Revision Type of Document Title Number Number Stress Report Reactor Vessel - Core Spray Nozzle 23A4904 0
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Or N Nfg A.S.s,). Y:1,.*v. Certifiedby:'b b fo P.E. Numbers m o 23575 Regj 6J red Profy sional ineer w th .% e015 State: A\Oris 4*, _As Date: \ L/ts /h5
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10.E '5 1:.550 9.75- 12.12 5 S.00- 11.750 13.440 9.750 D:!. TENS:0NS ARE IN INCHES Tigure / SATE DiD GEOMETRY l l l l l l
23A4904 ,, ,,. 4, NUctA m Ecov GEN ER AL U ELECTRIC SUSINESS OPERATION $ REV 0 ' PRIMARY STRESS ANALYSIS POR SECTION C-C. DESIGN CONDITIONS COMPONENT MEMBRANE MEMBRANE PLUS BENDING b (in)* 6.717 6.717 a (in)* 5.778 5.778 c (in)* 6.248 - t (in) 0.939 0.939 _ A (in**2) 36.860 36.860 2 (in**3) 115.791 107.697 L (in) - SATE-END 14.50 SLEEVE 20.56
$6 (ksi) 7.692 8.364 Sr (ksi) 3.663 8.515 Sx (ksi) -0.578 -1.250 TAU 6: (ksi) 0. 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 = PSI - PS3 (ksi) 8.280 < Se = 17.3 9.902 < 1.5*Se = 25.9 S123 = PS2 - PS3 (ksi) 4.231 9.476
/
SI12 = PSI - PS2 (ksi) 4.049 0.426 Pn, a 8.2SO S
*These include corrosion allowance, f8 : 9.1034 3 60 fW
, . .ha /62.2 pec I
U w -
C. Method of Analysis for Weld overlay stresses s. C-1 l l
The analysis of the core spray nozzle wold ovorloy vac
, - performed using the IBM PC-based finite element program sUPERSAP,** which is an enhancement of the well known s&P IVa*
program. i A two-dimensional axisymmetric model of the nozzle and one j t quarter of the reactor pressure vessel was developed. The radius + of the pressure vessel was adjusted to be 3.2 times the actual vessel radius to provide the proper stress concentration effects.** In actuality, for the region of the nozzle in consideration for this study, the correction is not really necessary. The model is shown in Figure C-1. t The first analysis performed was the unmodified nozzle subjected to a pressure of 1050 psig to verify the model. The nozzle hoop stress agreed within 4 percent of the value compute , using thin cylinder theory. The stress contours agree with typical nozzle analyses reported in References C4 and C5. See l Figures C-2, C-3 and C-4. ; The model was modified to incorporate the veld overlay, as s shown in Figure C-5. The measured axial shrinkage from the veld overlay l appitcation was obtained from the overlay data.a* The lower 4 value from the two overlays was a shrinkage of 0.009 inches over an 8.362 gage length. Due to the heat of welding and the associated reduced material strength the shrinkage is a combination of elestic and I plastic deformation. Since SUPERSAP is a linear program the shrinkage was approximated by imposing a decreased temperature field across the veld overlay nodes. 1 l C-2 i rv--+,_.m-_-_-_- , , . _ . _ , , , _ _ . . . _ . _ _ _ _ , _ , _ , _ _ _ _ _ _
If the constraint imposed by the surrounding nozzle and safe
- and is neglected, the required temperature differential can be obtained from the relationship 61/1 = Ea4T, where E is Young's modulus, a is the thermal expansion coefficient and 61/1 is the normalized shrinkage. .
A computed 4T of 160F was applied to the appropriate nodes and a stress analysis performed. , The analysis considsred the shrinkage stress, a pressure of 1050 psig and the steady state nozzle applied loads. As can be seen from Figure C-6, a significant region of compressive stress is created in the hoop stress direction. Figure C-7 shows the same analysis in the maximum principal stress direction; there is still a significant region of compressive stress. The conservatism of this approach can be verified by i examining the displacements of the overlay nodes. The actual t
; displacements from the analyais are only on the order of 0.002 inches, well smaller than t'te intended 0.009 inches, due to the constraint of the surrounding structure. Sensitivity studies showed that the region of compressive stress was not significantly altered by increasing the shrinkage, even though 1
the magnitude of the peak compressive stress was directly proportional to the shrinkage. Compare Figures C-6 and C-8. f The above analyses demonstrate that the veld overlays apply . a net compressive stress to a region of the nozzle and safe end significantly larger than that neces sary to suppress future flaw j growth. t I C-3 '
f
.e s
/
i Ve%g, WM
/
}
fin;f, Ike1t Reactor Vessel and Core Spray Nozzle and kfe End , i i 4 Fig C-1: Rfe Erd, Nozzle and Rector Pressure Yessel Finite Elerent Wodel l C-4 t
b hm O O M m O MSI EI S 'I N~ IIE
ED
- ~ E & - ~ .
= E = I $ $ w $ $ $ -
----====z=====e> -
4 I *e 3
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i
's 9
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,, 9 0'
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a < .. .< rw,,,,.,&+,,e v .a , i i i d i i i i a a i E u C-5
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n. t STRESS COMPONENT ey Maximum k Stress Minimum i . Stress < l
- 3 5 31,, '
/
!l X
' tf Gf
- l i
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2= Figure C-3. Pressure Case, 6=0' REF C4 C-6
iiis 3 ear 9 y Vermont Yankee Core Spray Nozzle
'a 4 5 Hoop Stress Contours E # Reaciar Pressure = 1050 psig g 379 C"3 e s S.
2 [ ssia e 2078 r - w
" A o 1 O
@ 777 3
\ _
November 8,1987 N"MlZZLE 4-NODE ELElENTS > CENTROID KRMAL STR.
~
\
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\\\T\\\\-
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~ ,
# , , n liy
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.M M M N N M M M M M M Fig, C-5: Weld Overlay Wodel Detail C-6
a . . 3 Ce %rc Spral Nozzlc Overlay
. 8 Ion of Conpressive Stress er j Reactor Pressure = 1050 psig j
.< N*(mal Applicd Loads i.. g.InG I ShriQ ,
g ? E
- 2 M
8 8 E
" / 2 my N w es...
November 10, 1987 N30VRLAY 4-t01E ELEENTS > CENTROID N[RMAL STREAS o
?<
9 4
- ~
7 tt
9' , 2 Vermont Yankee Core Spray Nozzle
; Region of Compressive Stress 1
i Reactor Presure = 1050 psig i a 4' Normal Applied Loads i a w 9 Et Nominal Shrinkoge o as a' O O V ! f l w i 1 i i N i Novenloer- 14, 1997 N50VRLAY 4-NODE ELEMENTS > CENTROID MAX PRINCIPAL STRESS
.. g N A"
% d Q
c Gll, Q 0
.as @
q, %
'. W g
d gg3Y . " 1 r ( # e' ... Y o h$ b ' a %aa (DD 3 '%
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h" p ./ ,. Fig. C-8 Vermont Yankee Core Spray Nozzle - One-half Nominal Shrinkage C-11
l R3forGncGO C1. Algor Interactive Systems, Software User Gu!de for SUPERSAP. C2. Rathe, K., Peterson, F., Wilson, E., "SAP IV - A Structural Analysis Program for Static and Dynamic Response of Linear l Systems", EERC 73-11, Earthquake Engineering Research Center, l j University of California, Berkeley, California, April 1974. l C3. Raju, P.P., Truitt, J.B., "Three-Dimensional versus Axisymmetric Finite-Element Analysis of a Cylindrical Vessel Inlet Nozzle Subject to Internal Pressure - A Comparative Study", Transactions of the ASME, Volume 100, May 1978. C4. EPRI Report NP-339, "Improved Evaluation of Nozzle Corner Cracking", March 1977. C5. WCAP-10561, "Yankee Primary Nozzles: Transient Development, Thermal Analysis, Stress Analysis and Fracture Evaluation", Westinghouse Electric Corporation , May 1984. C6. Vermont Yankee Engineering Design Change EDCR 85-1. C-12 i
D. Benchmarking of 8UPERSAP Computer Program t D-1
Tho cecputor prcgrco uscd for thic ctudy 10 tho IBM PC-baccd finite element program SUPERSAP.** It is an enhancement of the well known program SAP IV.** The original SAP IV program has been utilized and expanded upon by rany organizations, among then General Electric Company'8 and Brookhaven National Laboratory.** The Brookhaven Laboratory version, called EPIPE is used as a benchmark program for piping analysis computer programs. The General Electric Company program SAP 4007 is fully benchmarked under a 10CFR50 Appendix B quality assurance program and is used for teactor design. One of the program elements, called Type 4 (two dimensional axisymmetric solid) was used for the study. The suitability of the element is demonstrated by the following sample problem, the solution of a two dimensional axisymmetric pipe section subjected to thermal and pressure loadings. D-2
VE04001 THICK WALLED CYLINDER, PRESSURE AND TEMPERATURE Problem Definition s Ref ASME Pressure Vessel and Piping 1972 Computer Programs Verification, ed. by I.S. Tuba and W.B. Wright, ASME Publication I-24, Problems 3 and 4. E = 28 x 105 psi ~ l v = 0.25 e = 7.5 x 10-5 in/in/'F l
* 'O' '
,L p = 2000 psi
,, n a c non
-* y = 100'F 3
3 3 7 , 3 f YL 3v y T, = 0'T l T' R T= log (Ro/Ryog(f) l t l Problem Formulation . Note that with element type 4 the pressure can be applied only to the I-J face, so the numbering sequence of the elements must take this into account. Since the temperature is variable, the temperature at each node must be input. Use of the elemont load multipliers provides for the pressure as load case 1, and the thermal load as load case 2. Since this is a portion of a long cylinder, the Z displacements are prohibited, so only the Y ' degrees of freedom are active. Discussion of Results Classical ANSYS SAP IV ALGOR Error [ Pressures (psi) inside hoop stress 5200 5192 5199.3 5199 0.013% > outside hoop stress 3200 3197 3201.7 3202 0.053% Temperatures (psi) ! inside hoop stress -15,870 -15,723 -15,839 -15,840 0.20% < outside hoop stress 12,128 12,209 12,140 12,140 0.10%
2 1 1 S 1 I X A Y 5 0 1 9 4 8 7
)
5 1 0 0 4 0 6 6 E V . ( 7 8 9 2 1 1 5 5 4 y r a u n 1 a J 5 2 2 1 0 1 3 N,N
VE04001
. 3 EXAMPLE VE04001
, --- CUTPUT FILE ---
h l **** SUPERSAP ANALYSIS VERSION: 7.1 ) RELEASED: 7/30/85 OATE: February 5, 1987 TIME: 16:03:41 INPUT FILE........... .YE04001 EXAMPLE VE04001 -- TMiCK WALLED CYLINDER, PRESSURE AND TEMPERATURE
**** CONTROL INFORMATION 4
NUMBER OF NODE PolNTS (NUMNP) = 12 NUMBER OF ELEMENT TTPES (NELTYP) = 1 NUMBER OF LOAD CASES (LL) = 2 NUMBER OF FREQUENCIES (NF) = 0 GEOMETRIC STIFFNESS FLAG (GEOSTF) = 0 ANALYSl3 CODE (NDYN) = 0 SOLUTION MODE (MODEX) = 0 NUMBER OF ITERATION VECTORS (NAD) = 0 EQUATIONS PER BLOCK (KECB) = 0 TAPE 10 SAVE FLAG (NIOSV) = 0 NODAL DEFLECTION PRINTlHG (DEFPCH) = 0 CVERALL MATRIX PRINTING (GENPRT) = 0 ELEMENT MATRIX PRINTING (ELPRT) = 0 i WElGHT AND C.G. FLAG (IWTCG) = 0 BANDwlDTH MINIMlZATION FLAG (MINBND) = 0 FILE FORMAT FLAG (IPLT) = 0 NUMBER OF RESPONSE SPECTRA (NRSC) = 0 GRAVITATIONAL CONSTANT (GRAV) = 3.8640E+02 TOTAL BLANK COMMON (MTOT) = 30000 SANDwlDTH MINIMlZATION S P E C I F I' ED
**** NODAL DATA NODE BOUNDARY CONDITION CODES NODAL PolHT COORDINATES No. DX D) DZ RX RT RZ X Y Z T I 1 0 1 1 1 1 .000E+00 1.000E+01 .000E+00 1.000E+02 2 1 0 1 1 1 1 .000E+00 1.000E+01 1.000E+00 1.000E+02 3 1 0 1 1 1 1 .000E+00 1.100E+01 .000E+00 7.6?iE+01 4 1 0 1 1 1 1 .000E+00 1.100E*01 1.000E+00 7.649Ee11 5 1 0 1 1 1 1 .000E=00 1.200E+01 .000E*00 5.503E+01 6 1 0 1 1 1 1 .000E+00 F.200E+01 1.000E+00 5.503E+01 7 1 0 1 1 1 1 .000E+00 f.300E*01 .000E+00 3.529E+01 8 1 0 1 1 1 1 .000E+00 1.300E+01 1.000E+00 3.529E+01 9 1 0 1 1 1 1 .000E*00 1.400E+01 .000E+00 1.702E*01 10 1 0 1 1 1 1 .000E+00 1.400E+01 1.000E+00 1.702E*01 11 1 0 1 1 1 1 .000E+00 1.500E+01 .000E+00 .000E+00 12 1 0 1 1 1 1 .000E+00 1.500E+01 1.000E+00 .000E+00
**** TWO-O l HEN S ION AL SOLID ELEMENTS AXISYMMETRIC ANALYSl3 .
I NUMBER OF ELEMENTS = 5 NUMBER OF MATERIALS = l 1 MAXIMUM TEMPERATURES PER MATERIAL * , 1 ANALYSIS CODE = 0 AXISYMMETRIC.... 0 PLANE STRAIN.... 1 PLANE STRESS.... 2 l lNCOMPATIBLE DISPLACEMENT MODES = 0 INCLUDE......... 0 SUPPRESS........ 1 m - o su i
VE04001
**** MATERIAL PROPERTIES MATERIAL l.D. NUMBER = 1 NUMBER OF TEMPERATURES = 1 WEIGHT DENSITY = .0000E+00 MASS DENSITY = .0000E+00 SETA ANGLE = .0000E+00 TEMPERATURE E(N)/ E(S)/ E(T)/ NU(NS) NU(NT) NU(ST) G(NS)
ALPHA (N) ALPHA (S) ALPHA (T)
.0 2.800E-07 2.800E+07 2.800E+07 .250 .250 .250 1.120E+07 ~
7.500E-06 7.500E-06 7.500E-06
**** ELEMENT LOAD MULTIPLIERS CASE A CASE B CASE C CASE D TEMP .000E+00 1.000E+00 .000E+00 .000E+00 PRES 1.000E+00 .000E+00 .000E+00 .000E+00 X-DIR .000E+00 .000E+00 .000E+00 000E+00 Y-DIR .000E+00 .000E+00 .000E+00 .000E+00 2-DIR 000E+00 .000E+00 .000E+00 .000E+00
**** ELEMENT CONNECTIVITY DATA ELEM NODE NODE NODE NODE MAT'L REFERENCE l-J FACE OP THICKNESS NO. I J K L INDEX TEMP PRESSURE 1 2 1 3 4 1 .000E+00 2.000E+03 20 .000E+00 2 4 3 5 6 1 .000E+00 .000E+00 20 .000E+00 3 6 5 7 8 1 .000E+00 .000E+00 20 .000E*00 4 8 7 9 10 1 .000E*00 .000E+00 20 .000E+00 5 to 9 11 12 1 .000E+00 .000E+00 20 .000E+00
**** BANDWIDTH MINIMlZATION
=
MINBND (BANDWIDTH CONTROL PARAMETER) 1
**** MINIM 12ER DID NOT NEED TO REDUCE BANDWIDTH
**** EQUATION PARAMETERS TOTAL NUMBER OF EQUATIONS = 12 BANDWIDTH = 4 NUMBER OF EQUATIONS IN A BLOCK = 12 NUMBER OF BLOCKS = 1 BLOCKING MEMORY (KILOBYTES) = 240 AVAILABLE MEMORY (KILOBYTES) = 240 i
**** NODAL LOADS (STATIC) OR MASSES (DYNAMIC)
N0DE LOAD X-AXIS Y-AXIS Z-AXIS X-AXIS Y-AXIS Z-AXIS NUMBER CASE FORCE FORCE FORCE MOMENT MOMENT M0 MENT
**** ELEMENT LOAD MULTIPLIERS LOAD CASE CASE A CASE B CASE C CASE D
! 1 1.000E+00 .000E+00 .000E+00 .000E+00 l 2 .000E+00 1.000E+00 .000E=00 .000E+00 i l **** STIFFNESS MATRIX PARAMETERS l MINIMUM NON-ZERO DIAGONAL ELEMENT = 1.4056E+08 MAXIMUM DIAGONAL ELEMENT = 3.8364E+08 MAXIMUM / MINIMUM = 2.7295E+00 AVERAGE DIAGONAL ELEMENT = 2.8552E+08 DENSITT OF THE MATRIX = 7.9167E+01 l t
VED4001-
+++* TWO-DIMENSIONAL SOLID ELEMENT S1RESSES FACE Or CENTRolD (GLOBAL Y-Z)
FACE 1: L-1 SIDE (LOCAL)
. FACE 2: J-K SIDE (LOCAL)
FACE 3: 1-J Sire (LOCAL) FACE 4: K-L Sl9E-(LOCAL) ELEM CASE F -----~~----- STRESS COMPONENTS ------------ PRINCIPAL STRESSES NO.(MODE)A (IN-PLANE) C ' E SIEMA-11 SIGMA-22 SIGMA-33 TAU-12 SIGMA-MAX SIGMA-MIN 1 1-J -1.678E+03 7.938E+02 4.853E+03 .000E+00 7.938E+02 -1.678E+03 1 11 7.993E+02 -1.673E+03 4.870E+03 -2.319E+02 8.209E+02 -1.694E+03 1 1 2 7.993E+02 -1.673E+03 4.870E+03 2.319E+02 8.209E+02 -1.694E+03 1 1 3 -1.979E+03 8.052E+02 E3.19sE-03T .000E+00 8.052E+02 -1.979E+03 1 1 4 -1.356E+03 8.046E+02 4.373E+03 .000E+00 8.046E+02 -1.356E+03 1 2 0 -5.951E+02 -2.164E+04 -1.183E+04 000E+00 -5.951E+02 -2.164E+04
. 1 2 1 -2.165E+04 -6.086E+02 -1.187E+04 5.168E+02 -5.933E+02 -2.167E+04 1 2 2 -2.165E+04 -6.086E+02 -1.187E+04 -5.668E+02 -5.933E+02 -2.167E+04 1 2 3 -1.178E+02 -2.499E+04r-1.Se4E+os3 .000E+00 -1.178E+02 -2.499E+04 1 24 -1.189E+03 -1.840E+04 -8.173E+03 .000E+00 -1.189E+03 -1.840E+04 2 1 0 -1.131E+03 7.958E+02 4.315E+03 .000E+00 7.958E+02 -1.131E+03 2 11 7.999E+02 -1.127E+03 4.327E+03 -1.881E+02 8.181E+02 -1.146E+03 2 12 7.999E+02 -1.127E+03 4.327E+03 1.881E+02 8.181E+02 -1.146E+03 2 1 3 -1.361E+03 8.037E+02 4.576E+03 .000E+00 8.037E+02 -1.361E+03 2 1 4 -8.868E+02 8.034E+02 4.100E*03 .000E+00 8.034E+02 -8.868E+02 2 2 0 -1.280E+03 -1.536E*04 -4.905E+03 .000E+00 -1.280E+03 -1.536E+04 2 2 1 -1.536E+04 -1.284E+03 -4.919E+03 2.151E+02 -1.281E+03 -1.536E+04 2 2 2 -1.536E+04 -1.284E+03 -4.919E+03 -2.151E+02 -1.281E+03 -1.536E+04 2 2 3 -1.160E+03 -1.840E+04 -8.185E+03 .000E+00 -1.160E+03 -1.840E+04 2 24 -1.475E+03 -1.239E+04 -1.852E+03 .000E+00 -1.475E+03 -1.239E+04 3 1 0 -7.108E+02 7.972E+02 3.899E+03 .000E+00 7.972E+02 -7.108E+02 3 1.1 8.003E+02 -7.077E+02 3.909E+03 -1.563E+02 8.163E+02 -7.237E+02 3 1 2 8.003E+02 -7.077E+02 3.909E+03 1.563E+02 8.163E+02 -7.237E+02 3 1 3 -8.898E+02 8.028E+02 4.101E+03 .000E+00 8.028E+02 -8.898E+02 ,
3 1 4 -5.207E+02 8.026E+02 3.731E+03 .000E*00 8.026E+02 -5.207E+02 3 2 0 -1.342E*03 -9.597E+03 8.924E+02 .000E+00 -1.342E+03 -9.597E+03 3 2 1 -9.596E+03 -1.341E+03 8.945E+02 -3.472E+01 -1.341E+03 -9.596E+03 3 2 2 -9.596E+03 -1.341E+03 8.945E+02 3.472E+01 -1.341E+03 -9.596E+03 3 2 3 -1.456E+03 -1.239E+04 -1.860E+03 .000E+00 -1.456E+03 -1.239E+04 3 24 -1.278E+03 -6.857E+03 3.494E+03 .000E+00 -1.278E+03 -6.857E+03 4 1 0 -3.804E+02 7.981E+02 3.573E+03 000E+00 7.981E+02 -3.804E+02 4 11 8.005E+02 -3.779E+02 3.5E0E+03 -1.326E+02 8.153E+02 -3.926E+02 i 4 1 2 8.005E+02 -3.779E+02 3.580E+03 1.326E+02 8.153E+02 -3.926E+02
.000E+00 8.022E+02 -5.228E+02 i
4 1 3 -5.228E+02 8.022E+02 3.732E+03 4 1 4 -2.298E+02 8.021E+02 3.438E+03 .000E+00 8.021E+02 -2.298E+02
- 4 2 0 -9.952E+02 -4.280E+03 5.846E+03 .000E+00 -9.952E+02 -4.280E+03 l 4 21 -4.276E+03 -9.912E+02 5.858E+03 -2.161E+02 -9.770E+02 -4.290E+03 4 2 2 -4.276E+03 -9.912E+02 5.858E+03 2.161E+02 -9.770E+02 -4.290E+03 4 2 3 -1.265E+03 -6.856E+03 3.489E+03 .000E+00 -1.265E+03 -6.856E+03 4 24 -7.583E+02 -1.737E+03 8.103E+03 .000L+00 -7.583E+02 -1.737E+03 5 1 0 -1.160E+02 7.987E+02 3.311E+03 .000E+00 7.987E+02 -1.160E+02 5 1 1 8.007E+02 -1.140E+02 3.317E+03 -1.143E+02 8.148E+02 -l.281E+02 5 1 2 8.007E+02 -1.140E+02 3.317E+03 1.143E+02 8.148E+02 -1.281E+02 i
i 5 1 3 -2.312E+02 8.018E+02 7.439E+03 .000E+00 8.018E+02 -2.312E+02 5 14 5.279E+0? 8.017E+02 C.202E-03) .000E+00 8.017E+02 5.279E+00 5 2 0 -3.756E+02 6.578E+02 1.0ISE+04 .000E+00 6.578E+02 -3.756E+02 5 21 6.638E+02 -3.696E+02 1.017E+04 -3.499E+02 7.712E+02 -4.769E+02 5 2 2 6.638E+02 -3.696E+02 1.017E+04 3.499E+02 7.712E+02 -4.769E+02 5 2 3 -7.501E+02 -1.736E+03 8.100E+03 .000E+00 -7.501E+02 -1.736E+03 5 24 -2.350E+01 3.029E*03 (}.244E-043 .000E+00 3.029E+03 -2.350E+01 I S
YE04001
**** STATIC ANALYSIS LOAD CASE = '
1 DISPLACEMENTS / ROTATIONS (DEGREEF) 0F UNRESTRAINED N00ES NODE X- Y- Z- X- Y- Z-NUMBER TRANSLATION TRANSLATION TRANSLATION ROTATION ROTATION ROTATION 1 .0000E+00 1.9668E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 2 .0000E+00 1.9668E-03i .0000E+00 .0000E+00 .0000E+00 .0000E+00 3 .0000E+00 1.8565E-03 .0000E+00 0000E+00 .0000E+00 .0000E+00 4 .0000E+00 1.8565E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 5 .0000E+00 1.7704E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 6 .0000E+00 1.7704E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 7 .0000E+00 1.7031E-03 .0000E+00 .0000E+00 .0000E+00 .0000E*00 8 .0000E+00 1.7031E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 9 .0000E+00 1. 6 5 0 5 E- 03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 10 .0000E+00 1.6505E-03 .0000E+00 .0000E+00 .0000E+00 .C000E*00 11 .0000E+00 1.6097E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 12 .0000E+00 1.6097E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00
**** STATIC ANALYSIS LOAD CASE = 2 DISPLACEMENTS / ROTATIONS (DEGREES) 0F UNRESTRAINED N0 DES NODE X- Y- Z- X- Y- Z-NUMBER TRANSLATION TRANSLATION TRANSLATION ROTATION ROTATION ROTATION 1 .0000E+00 4.0721E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 2 .0000E+00 4.0721E-03 .0000E*00 .0000E+00 .0000E+00 .0000E+00 3 .0000E+00 5.0115E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 4 .0000E+00 5.0115E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 5 0000E+00 5.6400E-03 .0000E+00 .0000E+00 0000E+00 .0000E+00 6 .0000E+00 5.6400E-03 0000E+00 .0000E+00 .0000E+00 .0000E+00 7 .0000E+00 6.0085E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 8 .0000E+00 6.0085E-03 .0000E+00 .0000E+00 .0000E*00 .0000E+00 9 .0000E+00 6.1551E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 10 .0000E+00 6.1551E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00 11 .0000E+00 6.1090E-03 .0000E+00 .0000E+00 0000E+00 .0000E+00 12 .0000E+00 6.1090E-03 .0000E+00 .0000E+00 .0000E+00 .0000E+00
$O
References ! D1. Algor Interactive Systems, Software User Guide for SUPERSAP. , 1 D2. Bathe, K., Peterson, F., Wilson, E., "SAP IV - A Structural l Analysis Program for Static and Dynamic Response of Linear Systems", EERC 73-11, Earthquake Engineering Research Center, University of California, Berkeley, California, April 1974. D3. NEDO-10909, "User's Manual, SAP 4G07, Static and Dynamic Analysis of Mechanical and Piping Components by Finite Element Methods", Revision 7, December 1979. . D4. Bezler, P., Hartzman, M., and Reich, M., "EPIPE - An Elastic Piping Program for Static and Dynamic Analysis, NUREG/CR-1698. t l t l l D-9 l
E. Results of 1987 Weld overlay Inspections { t l' E-1
VERMONT YANKEE NUCLEAR POWER CORPORATION RD 5, Box 169, Ferry Road, Brattleboro,VT 05301 , , , , , ENGINEERING OFFICE 1671 WOACEST ER ROAD
** FRAMINGH AM. M ASS ACHUSETTs ot701
. 1stt*<o tsit4 n dico Detober 20, 1987 FVY 87-100 .
United States Nuclear Regulatory Cornission Washington, DC 20555 Attention: Office of Nuclear Reactor Regulation Mr. V. L. Rooney, Senior Project Manager Project Directorate I-3 Division of Reactor Projects I/II
References:
(a) License No. DPR-28 (Docket No. 50-271) (b) Letter, VYNPC to USNRC, FVY 86-36, dated May 5, 1986 (c) Letter, VYNPC to USNRC, TVY 86-49, dated June 2, 1986 (d) Letter, USNRC to VYNPC, NYY 86-113, dated June 16, 1986 (e) Letter, VYNPC to USNRC, TVY 87-07, dated January 12, 1987 (f) Letter, VYNPC to USNRC, FVY 87-50, dated May 7, 1987 (g) Letter, USNRC to VYKPC, NVY 87-81, dated May 28, 1967 Subj ect: 1987 Outage Core Spray Safe-End Weld Overlay Inspection Results
Dear Sir:
By letter dated May 28,1987 (Reference (g)), the Nuclear Regulatory Commission (NRC) approved Vermont Yankee's plans to inspect the two overlay repaired core spray safe-ends instead of replacing the= during the 1987 refueling outage, nat letter also requested Ver=ent Yankee to provide the results of the inspection no later than three weeks after plant startup following the 1967 refueling outage. In accordance with that request Ver=ent Yankee herein provides the 1987 refueling outage liquid penetrant and ultrasonic exarination results of the Vermont Yankee Core Spray System safe-end to reactor vessel nozzle weld overlay repair welds. nese examinations showed the weld overlays and the underlying no::le, weld, and safe-end material to be free from new or propagating defects, ne exs**a.ation results are discussed below. D e.11guld penetrant examination was conducted prior to ultrasonic examination. ne solvent removable red dye technique was used to examine the weld overlay surface, the overlay end tapers, and the safe-end and no: le base material 1:=cediately adjacent to the overlay. Exarination parameters were consistent with ASME, Section II, and Yankee Atomic Electric Co=pany (YAEC) Procedure YA-PE-2. n e examinatien was conducted by Level III personnel
- -~ , - ,
October 20, 1987 i United States Nuclear Regulatory Commission page 2 Attention: Mr. V. L. Rooney qualified in accordance with SNI-TC-1A. Independent substantiating interpretation was conducted by a second Level III. Minor nonrelevant indications were noted between weld beads in the as-welded end tapers. These indications initiated the secondary substantiating interpretation and were detenmined not relevant to this examination, nor were they located so as to mask potentially relevant indications. Ultrasonic examination to detect possible flaws was conducted using two Level II and one Level III exaniner qualified at the EPRI NDE Center to examine weld overlay repairs. An additional Level III examiner qualified in accordance with the EPRI NDE Center program for sizing of planar flaws was also on staff to serve as technical reviewer and to aid in measuring indications if found. Examination techniques were based upon the EPRI weld overlay inspection methodology with modifications and additions empirically demonstrated on the Vermont Yankee weld overlay mockup. The EPRI overlay ISI methodology relies on detection of crack faces utilizing 600 or 700 refracted longitudinal i waves incident at, or nearly perpendicular to, an oriented, propagating crack face. Transducer size selection is a function of long-range overlay roughness. Transducer focal length is based on ampirical calibration demonstration. The program icplemented at Vermont Yankee was significantly more in depth than the EPRI methodology, even though Vermont Yankee has determined the inspection of Incenel weld overlays to be somewhat less difficult than stainless steel overlays. Enhanced surface preparation requirements at installation allowed Vermont Yankee more latitude in transducer selection. Transducer size and focal length were selected based upon the parameters believed necessary for proper examination. Each transducer was then demonstrated capable of detecting diffracted signals within its focal range. l particular attention was paid to the WOL-base metal interf ace. By application l of 700 (with accompanying OD creeping wave), 600, and 450F transducers nominally focused at 1.5",1.7", and 1.9" of retal path, respectively, angle beam scans were conducted looking for both axial and circumferential flaws. In addition, a 00 (straight bea=) interrogation of the entire volume was made to detect any developing indications as might be experienced at the weld j overlay interface. Based on the results of these examinations, wherein neither relevant liquid penetrant indications nor ultrasonic indications were found, Vermont Yankee concluded that acceptable overlay service had been da=onstrated for this fuel cycle and that replacament of the core spray safe-ends during the 1987 outage was not warranted. We are currently updating our weld overlay documentation to incorporate the results of this inspection and the relevance of the Bk'R nozzle cracking detected in a foreign reactor. Upon completion of this effort, we will notify you of our evaluation results and future plans with regard to replacement of the saf e-ends. . 4
*
- w~-w+~.- --,~e--,.n __ . , , _
United States Nuclear Regulatory Comission October 20, 1987 Attention: Mr. V. L. Rooney Page 3 -o We trust that this infonnation is acceptable; however, Vermont Yankee is available to meet with you to present additional information regarding the 1987 refueling outage inspection methodology and results at your convenience. Very truly yours. VERMONT YAEKEE NUCLEAR POWER CORPORATION
. A J
R. W. Cap tick Licensing Engineer ,
^'
RWO/25.193 e P e 5
F. Development and Application of Weld Overlays F-1
The EPRI/ Utility BWR Owners Group for IGSCC Research was
- formed in 1977 to address the causes and cures for intergranular stress corrosion cracking in BWR piping systens. In 1985 EPRI and Georgia Power Company recognized that one potential area for IGSCC did not have a suitable mitigation approach other than replacement. This was the nozzle to safe end weld on the reactor pressure vessel.
In order to address this shortcoming EPRI, Georgia Power and Structural Integrity Associates initiated a research effort to develop a veld overlay repair process that would not require a post veld heat treatment. EPRI had previously demonstrated that machine gas tungsten arc welding (GTAW) was superior to the Code-approved shielded metal arc (SMAW) half bead process ri. This new process was approved in ASME Code Case N-432"*. The research strategy was to apply the existing EPRI approach to a lov alloy steel nozzle as a weld overlay, instead of a cavity repair. The details of the development program vill be reported in an EPRI report scheduled for publication in 1988. The principal outcome of the project was demonstration that a l Veld overlay could be applied to a lov alloy steel nozzle with i l adequate material tempering without post veld heat treatment. The researchers demonstrated that result on the same plate used in the earlier project identical tempering results were achieved. t When potential IGSCC was detected in the Vermont Yankee core spray nozzle to safe end welds a decision was made to apply veld overlays. F-2 L ,,
1 Plant specific development was performed at Vermont Yankee, l i first on carbon steel pipe and then on a fabricated mockup using SA 508 and Inconel 600. The purpose of the development program I was to select equipment specific welding parameters and then verify that tnose paraceters achieved the proper degree of tempering in the SA 508 material. The overlay was designed to be applied in two portions. The first portion was the butter / temper layers. The purpose of this portion was to 1) achieve proper tempering of the base metal,
- 2) accommodate the dilution resulting from applying Inconel 82 on SA 509 and 3) provide the code required "butter" to allow subsequent velding to be performed without post veld heat treatment.
The development program showed that a three layer butter / temper region of at least 0.125 inch thickness achieved all three goals. Figure F-1 shows a plot of hardness in the lov alloy steel after one and three layers of veld metal were applied. As can be seen, the third layer achieved a hardness reduction below the target value of Rockwell C35. Figure F-2 shows the veld layer chemistry after one, two and three layers. The third layer has achieved a chemistry very close to Inconel 82, ensuring that subsequent layers vill be i undiluted Inconel 82. Finally, the 0.125 inch thickness satisfies ASME Code l requirements for velding on cladding"2 l i I F-3 i i \_
The second portion of the overlay is the actual structural
' overlay. The rules of ASME Section XI'* vere used to design the overlay. The input loads were taken from the reactor vessel design report **.
Since the overlays were being applied at the end of the recirculation system replacement outage it was desired to have a minimum impact on the critical path. To support this need a study was performed to determine if the effect of applying the structural portion of the overlay without water in the nozzle (the butter / temper portion must be applied dry to ensure proper pre- and post heat). As can be seen from Figure F-3 the temperature pattern, and thus the residual stress pattern, in the nozzle under the overlay is the same with or without water inside the nozzle. For this reason the overlay was allowed to be applied wet or dry. (In actuality, plant conditions were such that the overlays were applied with the core spray nozzles flooded.) In summary, it is Vermont Yankee's conclusion that a satisfactory veld overlay can be applied to a lov alloy steel nozzle providing the following conditions are satisfied:
- 1. develop and qualify equipment and vendor specific welding procedures,
- 2. apply a three layer (minimum) butter / temper layer at least 0.125 inches thick, using the pre- and post heat requirements of ASME Code Case N-432,
- 3. apply a full structural overlay, designed in accordance with ASME Section XI, vet or dry,
- 4. observe the Code requirements for overlay length,
- 5. ensure a proper surface finish to allow ultrasonic examination, following the EPRI inspection guidelines.
F-4
Micro Htrdnaca Area Inco 82 Weld y Metal overlay p S M ' s _ _ _ _ _ _ _ _ __ \ ._ _ __ _l_ _; - - -
- i-HAZ _/ \ ,
- I I .
Inconel 600 I L w! A508 CL2 8
- / \
/
Inco 82 Weld Metal _ .- Inco 182 Weld Metal Rc41 400 I Rc35.5 350 4 8 4
. a
' 4 R#3O 300 a
e o a 4
Rc22 250 K'
. i'
** 0 91 200 8 A-i E79 n 150 3
W h 100 50
.030' .040' .050* 060' .070* .000* .090*
0' .010' .020* DEPTH BEffW FUBION LINE
* = First Layer Bardt.ess.
e - Third Layer Mardness After Temper Heat Treatment. 4 - Final Layer hardness. FIDEf. TWIIe AND FINAL 1AYER MICRO RAPDNESS Fig. F-1: Base Metal Hardness Profiles After Overlay Welding l F-5
SAMPLE A SAMPLE C SAMPLE C 1ST LAYER 2ND LAYER 3RD LAYER
% XRF FE 50.16 AL 19.04 7.37
.115 .220 .169 P .010 SI
.004 .004
.144 .108 TI .130
.147 .243 .274 CU .070 .047 MN .040 2.03 3.03 3.34 NI 35.70 .57,86
;CR 66.61 10.16 16,91 1G.30 FC .011 .029 TA .023
.021 .007 <.002 ND 1.38 2.45 2.69
( l l l l i l ) Fig. F-2: Weld Layer Chemistry - SA 508 Base Metal and Inconel 82 Weld Metal l l F-6 l
1r 6 T EMP ER A T'JR E ' (c) 5 ICD 3 300 C 500 D 70g
/ .,,.___A_._.
a r. n , - " p,tr//sa ! % -. - E 9Ca i p.,,_. w- _M.- , F 1100 l o.u,C s% M#v#
~
G H ']500 I 17CO J 19CO K 2100
+ A+
Teaterat.,re 315tribution heing the App 16Catton of SetenJ '441d Overlay layer with C aling '.a'e l% 3de TEMPERAYlC7 c.= > A 100. 0 300' c 500
~; ' -- _ g3s ~ - gl[ s , ----_
0 E 700 900
?
a y ge [- - - [ r -{ 2 8 F 1100
- G 13Cn
/
H 150b I 1700 J 1900 K 2100
-=/ _ _ . _ _ _ _ . . _ _ _ . _ _ _ _ . - .. =
Tmrature Olstribution During the AppitCatton of SecoM Weld Overlay tayee with 40 Cooling Water In$10e Fig. F-3: %ernal Profiles Under overlay with and Without Water at ID Surface F-7 . ii
I References F1. EPRI Report NP-3614, "Repair Welding of Heavy Section Steel Components in LWRs", July, 1984. F2. ASME Code Case N-432, "Repair Welding Using Automatic or Machine Gas-Tungsten Arc welding (GT.t?) Temperbead Technique, Section XI, Division 1, February 20, 1986. F3. ASM4 Boiler and Pressure Vessel Code, Section XI, Subsection IWB-3641, 1983 Edition thru Summer 1965 Addenda. F4. Chicago Bridge and Iron Stress Report 9-6202-1, Section I-S-7, August 1969. 4 F-8 _ _ . _ _ _ . _ _ . _ _ . _ _ _ _._ __ _ _. _ ._.__ _}}