NOC-AE-06002068, Response to Request for Additional Information: Proposed Alternative to ASME Section XI Requirements for Application of a Weld Overlay (RR-ENG-2-43)

Response to Request for Additional Information: Proposed Alternative to ASME Section XI Requirements for Application of a Weld Overlay (RR-ENG-2-43)

ML062850090
Person / Time
Site:	South Texas
Issue date:	09/28/2006
From:	Rencurrel D Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
G25, NOC-AE-06002068, RR-ENG-2-43, STI: 32060797, TAC MD1414, TAC MD1423
Download: ML062850090 (4)

Text

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September 28, 2006 NOC-AE-06002068 File No.: G25 10 CER 50.55a U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 South Texas Project Units 1 and 2 Docket No. STN 50-498, STN 50-499 Response to Request for Additional Information:

Proposed Alternative to ASME Section XI Requirements for Application of a Weld Overlay (RR-ENG-2-43) (TAC Nos. MD1 414-1423)

References:

(1) Letter dated May 1, 2006, from M. J. Berg, STPNOC, to NRC Document Control Desk, "Proposed Alternative to ASME Section XI Requirements for Application of a Weld Overlay (RR-ENG-2-43)," (NOC-AE-06002000)

(2) Letter dated August 22, 2006, from M. J. Berg, STPNOC, to NRC Document Control Desk, "Response to Request for Additional Information on Proposed Alternative to ASME Section Xl Requirements for Application of a Weld Overlay (RR-ENG-2-43) (TAC Nos. MD141 4-1 423)," (NOC-AE-06002055)"

(3) Letter dated September 19, 2006, from David W. Rencurrel, STPNOC, to NRC Document Control Desk, "Commitment in Support of Proposed Alternative to ASME Section XI Requirements for Application of a Weld Overlay (RR-ENG-2-43) (TAO Nos. MD141 4-1 423)," (NOC-AE-06002066)

STP Nuclear Operating Company (STPNOC) provides the attached responses to NRC questions regarding requested alternatives to the requirements of the American Society of Mechanical Engineers (ASME) Code,Section XI for installation and examination of full structural weld overlays for dissimilar metal and safe end-to-piping stainless steel (SS) butt welds.

Reference 1 is the initial request for relief, and reference 2 is the response to the first set of NRC questions. Reference 2 includes commitments to perform flaw evaluations and shrinkage stress effects analyses and to submit a final evaluation report. Reference 3 provides a commitment to provide inspection results following completion of the weld overlays. To provide clarification of actions to be taken by STPNOC, these previously stated commitments are re-issued with appropriate rewording to address the NRC request for additional information (RAI) received September 21, 2006.

STPNOC will complete stress analysis summaries of the pre-emptive weld overlay prior to restart of Unit 1 and will provide the summaries to the NRC within four weeks after restart from the Unit 1 (Fall 2006) refueling outage. Similarly, stress analysis summaries will be completed prior to the restart of Unit 2 and provided to the NRC within four weeks after restart from the Unit 2 (Spring 2007) refueling outage. This commitment supports the response to RAI #2.

STI: 32060797 ID L

NOC-AE-06002068 Page 2 of 3 For each unit, STPNOC will provide the weld overlay ultrasonic examination results to the NRC.

Included in the results will be a discussion of any repairs to the overlay material and/or base metal and the reason for the repair. The results will be submitted within 14 days after completion of the last ultrasonic examination of the weld overlays for each unit. This commitment addresses RAI #2.

Data provided in the report will include disposition of indications using ASME Section Xl standards. Subsequent inservice examination of the structural weld overlays will be in accordance with ASME Section XI, Appendix Q, Q-4300. This commitment addresses RAI #1.

The restated commitments are listed in the attachments.

To support activities to be performed in the Unit 1 Fall 2006 refueling outage, NRC approval of the subject relief request is requested by October 2, 2006.

If you have any questions, please contact either Mr. P. L. Walker at (361) 972-8392 or me at (361) 972-7867.

David W. Rencurrel Vice President Engineer ga

& Strategic Projects PLW

Attachment:

List of Commitments

NOC-AE-06002068 Page 3 of 3 cc:

(paper copy) (electronic copy)

Regional Administrator, Region IV A. H. Gutterman, Esquire U. S. Nuclear Regulatory Commission Morgan, Lewis & Bockius LLP 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Mohan C.Thadani U. S. Nuclear Regulatory Commission Richard A. Ratliff Steve Winn Bureau of Radiation Control Christine Jacobs Texas Department of State Health Services Eddy Daniels 1100 West 49th Street NRG South Texas LP Austin, TX 78756-3189 C. Kirksey City of Austin Senior Resident Inspector J. J. Nesrsta.

U. S. Nuclear Regulatory Commission R. K. Temple P. 0. Box 289, Mail Code: MN1 16 E. Alarcon Wadsworth, TX 77483 City Public Service C. M. Canady Jon C.Wood City of Austin Cox Smith Matthews Electric Utility Department 721 Barton Springs Road Austin, TX 78704

Attachment NOC-AE-06002068 Page 1 of 1 LIST OF COMMITMENTS The following table identifies the actions in this document to which the STP Nuclear Operating Company (STPNOC) has committed. Statements in this submittal with the exception of those in the table below are provided for information purposes and are not considered commitments.

Please direct questions regarding these commitments to Philip Walker at (361) 972-8392.

Commitment Expected CR Action Completion Dates Nos.

STPNOC will complete stress analysis summaries of the pre- 11/28/2006 (Unit 1) 05-15744-42 emptive weld overlay prior to restart of Unit 1 and provide the052/07(nt)0514-4 summaries to the NRC within four weeks after restart from the052/07(nt)0-14-4 Unit 1 (Fall 2006) refueling outage.

Similarly, stress analysis summaries will be completed prior to the restart of Unit 2 and provided to the NRC within four weeks after restart from the Unit 2 (Spring 2007) refueling outage.

For each unit, STPNOC will provide the pre-emptive weld 11/07/2006 (Unit 1) 05-15744-43 overlay ultrasonic examination results to the NRC within 14 05/07/2007 (Unit 2) 05-15744-45 days after completion of UT examination of the weld overlays. The results will include:

" A list of indications detected.1

" The disposition of all indications using the standards of ASME Section Xl, IWB-3514-2 and/or IWB-3514-3 criteria, and

" The type and nature of the indications, if possible.2 Included in the results will be a discussion of any repairs to the overlay material and/or base metal and the reason for the repair.

Subsequent inservice examination of the structural weld overlays will be in accordance with ASME Section Xl, Appendix Q, 0-4300.

1. The recording criteria of the ultrasonic examination procedure to be used for the examination weld overlays (PDI-UT-8, Revision F) require that all indications, regardless of amplitude, be investigated to the extent necessary to provide accurate characterization, identity, and location. Additionally the procedure requires that all indications, regardless of amplitude, that cannot be clearly attributed to the geometry of the overlay configuration be considered flaw indications.

2. Ultrasonic examination procedure PDI-UT-8, Revision F, requires that all suspected flaw indications be plotted on a cross-sectional drawing of the weld and that the plots should accurately identify the specific origin of the reflector.