ML051650266
| ML051650266 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/03/2005 |
| From: | Fadel D Indiana Michigan Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| AEP:NRC:5055-06 | |
| Download: ML051650266 (9) | |
Text
Indiana Michigan Power INDIANA Cook Nuclear Plant MICHIGAN One Cook Place Bridgman, MI 49106 PCERU'U AEP~com A unit of American Electric Power June 3, 2005 AEP:NRC:5055-06 10 CFR 50.55a Docket No:
50-315 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop O-P1-17 Washington, DC 20555-0001 Donald C. Cook Nuclear Plant Unit 1 PRESSURIZER SAFETY NOZZLE STAINLESS STEEL SAFE END WELD CIRCUMFERENTIAL FLAW EVALUATION This letter is being submitted for Nuclear Regulatory Commission (NRC) review and approval in accordance with the requirements of the American Society of Mechanical Engineers (ASME) Code,Section XI, 1989 Edition, Paragraph IWB-3640.
During the Unit 1 Cycle 20 Refueling Outage, Indiana Michigan Power Company (I&M) personnel performed non-destructive examinations (NDE) of the Unit 1 pressurizer Alloy 82/182 welds.
During the examinations, I&M identified the need to perform a repair on weld 1-PRZ-23, and a weld overlay was applied for the repair. The subsequent NDE of the repair found the weld overlay to be acceptable in addressing weld 1-PRZ-23. However, the NDE identified the presence of a flaw in the pressurizer safety nozzle stainless steel safe end weld (1-RC-9-01F). The flaw did not meet the acceptance criteria of the ASME Code,Section XI, 1989 Edition, Table IWB-3514-2 and an evaluation in accordance with ASME Code,Section XI, 1989 Edition, Paragraph IWB-3640 was performed for both an axially oriented flaw and a circumferentially oriented flaw by Westinghouse Electric Company (Westinghouse) personnel. As the consequences of circumferential flaw growth are more significant than the consequences of axial flaw growth, the summary of the circumferentially oriented flaw evaluation is provided as Attachment 1 to this letter.
The Westinghouse evaluation summary report has undergone two editorial revisions. Revision 1 incorporated owner review comments to the Westinghouse evaluation, and Revision 2 revised the proprietary classification of the evaluation to allow public disclosure. Revision 2 of the summary is being provided for NRC review and approval. to this letter provides the design loads that were provided to Westinghouse personnel for use in the flaw evaluation using the ASME Code,Section XI, 1989 Edition, Appendix C guidelines.
The Westinghouse evaluation determined that the flaw was acceptable and would experience negligible growth over the life of the plant (60 years).
Based on the evaluation,
U. S. Nuclear Regulatory Commission Page 2 AEP:NRC:5055-06 Westinghouse personnel concluded that the circumferential flaw met the ASME Code,Section XI, 1989 Edition, Paragraph IWB-3640 flaw acceptance criteria and was acceptable for the duration of the plant life and did not require repair.
Based on the above information and the evaluation summarized in Attachment 1, subject to NRC review and approval, I&M concludes that the pressurizer nozzle weld 1-RC-9-O1F is acceptable for service, and system operability is maintained.
This letter contains no new commitments.
Should you have any questions, please contact Mr. John A. Zwolinski, Safety Assurance Director, at (269) 466-2428.
Sincerely, Engineering Vice President RGV/rdw Attachments: 1. Pressurizer Safety Nozzle (SST Safe End Weld) Circumferential Flaw Evaluation
- 2. AEP Design Information Transmittal DIT-B-02976-00 C:
R. Aben - Department of Labor and Economic Growth, w/o attachments J. L. Caldwell - NRC Region III K. D. Curry - AEP Ft. Wayne, w/o attachments J. T. King - MPSC, w/o attachments C. F. Lyon - NRC Washington, DC MDEQ - WHMD/HWRPS, w/o attachments NRC Resident Inspector to AEP:NRC:5055-06 Pressurizer Safety Nozzle (SST Safe End Weld)
Circumferential Flaw Evaluation i
Westinghouse Non-Proprietary Class 3 Westinghouse Westinghouse Electric Company Nuclear Services P.O. Box 355 Pittsburgh, Pennsylvania 15230-0355 USA Mr. Paul Donavin American Electric Power Donald C. Cook Nuclear Plant One Cook Place Bridgman, MI 49106 Direct tel:
Direct fax:
e-mail:
Purchase Order.
Sales order Our ref 412-374-4378 412-374-3451 harschkewestinghouse.com C-7693 Release 05-007 33762 AEP-05-50 Revision 2 May 24,2005 American Electric Power Donald C. Cook Unit 1 Pressurizer Safety Nozzle (SST Safe End Weld) Circumferential Flaw Evaluation References I. AEP Design Information Transmittal (DIT) No. DIT-S-01505 dated 5/18/2005,
Subject:
Provide Ultrasonic Data from Weld 1-RC-9-OIF Examination for IWB 3600 Analysis.
- 2.
ASME Code Section XI, "Rules of In-service Inspection of Nuclear Power Plant Components,"
1989 Edition (no addenda).
- 3. Westinghouse Letter AEP-0545, "Pressurizer Safety Nozzle (SST Safe End Weld) Axial Flaw Evaluation," dated 05/4/2005.
During the inspection of the pressurizer butt welds at D. C. Cook Unit 1, a circumferential indication was detected in the stainless steel safe end weld on one of the three pressurizer safety valve nozzles.
Per the request of American Electric Power (AEP), Westinghouse has performed an evaluation of the circumferential indication discovered in the pressurizer safety nozzle stainless steel (SST) safe end weld.
The purpose of the evaluation is to demonstrate that the detected circumferential flaw is acceptable for the duration of the plant life (60 years) without repair. The following provides a brief summary of the evaluation and the associated results:
Westinghouse Electric Company LLC P.O. Box 355 Pittsburgh, PA 15230-0355
° 2005 Westinghouse Electric Company LLC All Rights Reserved Official Record Electronically Approved in EDMS 2000 A BNFL Group company
.1
. p.
Page 2 Our ref: AEP-05-50 Revision 2 May 24, 2005 As-Found Circumferential Flaw Configuration Ill L0.30"l 0.646" 0.64" 4
_)
2a= 0.29" S=0.09" Inside Surface Flaw Evaluation To remain as a sub-surface flaw, the criteria S > 0.4a must be met [2], therefore maximum allowable sub-surface flaw (2a) = 0.45" based on S = 0.09".
The maximum allowable circumferential flaw is determined to be 75% of the wall thickness using the flaw evaluation procedures in Section XI Appendix C [2] as the guidelines.
Using the fatigue crack growth reference curve for austenitic steel in air from Section XI Appendix (C [2],
the fatigue crack growth for the as-found sub-surface flaw for 10, 20, 30 and 40 years is negligible and is shown below:
Initial crack Crack depth after depth (a) 10 years 20 years 1
30 years 1
40 years 0.145" 0.145" 0.145" 0.145" 0.145" The design transient cycles used in the fatigue crack growth calculation is based on a plant life of 40 years. Since the design transient cycles for a plant life of 40 years are the same as that for 60 years.
Fatigue crack growth for 60 years is also expected to be negligible.
Conclusion The as-found circumferential flaw in the pressurizer safety nozzle stainless steel weld has been shown to meet the Section XI IWB-3640 flaw acceptance criteria using the flaw evaluation procedures in-Section XI Appendix C as the guidelines. The flaw is acceptable for the duration of the plant life (60 years) and no repair is necessary.
This letter supersedes Westinghouse Letter AEP-05-45, entitled "Pressurizer Safety Nozzle (SST Safe End Weld) Axial Flaw Evaluation" [3] and Westinghouse Letter AEP-05-50, entitled "Pressurizer Safety Nozzle (SST Safe End Weld) Circumferential Flaw Evaluation" (Revision 0 dated 05/18/2005 and Revision I dated 05/19/2005). Reference 2 has been changed to reflect ASME Code Section XI, 1989 Edition (no addenda), which is currently the Code of record at D.C. Cook. This document is considered Westinghouse Non-Proprietary Class 3.
A BNFL Group company
Page 3 Our ref: AEP-05-50 Revision 2 May24, 2005 If you have any specific questions regarding the information in this letter, please contact Mr. Chris Ng of Westinghouse Piping Analysis and Fracture Mechanics (724) 722-6030 or me at (412) 374-4378.
Very truly yours, WESTINGHOUSE ELECTRIC COMPANY Kyle Harsche Customer Projects Manager A BNFL Group company to AEP:NRC:5055-06 AEP Design Information Transmittal DIT-B-02976-00
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AEP DESIGN INFORMATION TRANSMITTAL (DIT)
DIT Form, Part ii originating Organization,-
SAFETY-RELATED' AEP DIT No DIT-B02976-00 El NON-SAFETY-RELATED oOther(specify)
D.C. Cook Unit: 1 Page I
of 2
System Designation RCS. Reactor Coolant System To Mr. Di Tang, Westinghouse
Subject:
Provide design inputs for design of the weld overlay on weld l-PRZ-23 of pressurizer safety valve line nozzle.
Paul R. Donavin Principal Engineer 4/21/05 Preparer Position Preparer's Signature Date T. Satyan-Sharna Principal Engineer 4/21/05 Reviewer Position Date
_ _ C_
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O__n g h or Approver Position Approver's Signature Date Status of Information: 0 Approved for Use D Unverified Method and Schedule of Verification for Unverified DMTs N/A CR#
None Holds Associated with Unverified DrTs:
None Description of Information:
The information contains operating pressures and temperature, piping loads, and design Codes.
The operating pressure is 2085 psig, Operating Temperature is 631IF, (Ref.3) and the piping loads are attached from Reference 1.
Purpose of Issuance (Including any Precautions or Umitations):
Provide operating parameters for weld overlay design on 1-PRZ-23.
Source of Information:
Engineering Judgemnent Used? 0 Yes 0 No Controlled Reference / Document No.:
- 1. Teledyne Engineering Services, TR-5364-3, Rev.0 (Archived)
Uncontrolled Reference / Document No.:
- 2. ASME B&PV Nuclear Code Case N-504-2
- 3. RfTIME Record for 2/15105 at 00:00 Distribution: Copy to Requestor Di Tang, Westinghouse Copy to DIT Administrator File Original to NDM (Transmitted by D1T Administrator)
This form is derived from the information in 12-EHP-5040-DES-001, Control of Design Input.
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~CONTET QUA1Y IS This form is derived from the information in 12-EHP-5040-DES-001, Control of Design Input.