ULNRC-05292, Clarification of Response to Request for Additional Information Regarding 10 CFR 50.55a Request to Support Application of Structural Weld Overlays for Pressurizer Nozzle Welds

Clarification of Response to Request for Additional Information Regarding 10 CFR 50.55a Request to Support Application of Structural Weld Overlays for Pressurizer Nozzle Welds

ML071020041
Person / Time
Site:	Callaway
Issue date:	04/05/2007
From:	Fitzgerald D AmerenUE, Union Electric Co
To:	Document Control Desk, NRC/NRR/ADRO
References
FOIA/PA-2008-0001, ULNRC-05292, ULNRC-05385, ULNRC-05395
Download: ML071020041 (4)

Text

AmerenUE PO Box 620

/

Callaway Plant Fulton, MO 65251 April 5, 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Ladies and Gentlemen: ULNRC-05395 WAmeren DOCKET NUMBER 50-483 Ui F CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

CLARIFICATION OF RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING 10 CFR 50.55a REQUEST TO SUPPORT APPLICATION OF STRUCTURAL WELD OVERLAYS FOR PRESSURIZER NOZZLE WELDS Reference 1: AmerenUE letter ULNRC-05292, "Request for Relief from ASME Section XI Repair and Replacement Requirements: Proposed Alternatives for Application of Structural Weld Overlays to Pressurizer Nozzle Welds," dated August 14, 2006 Reference 2: AmerenUE letter ULNRC-05385, "Response to Request for Additional Information Regarding 10 CFR 50.55a Request for Relief from ASME Section XI Repair and Replacement Requirements: Proposed Alternatives for Application of Structural Weld Overlays to Pressurizer Nozzle Welds," dated March 26, 2007 By letter dated August 14, 2006 (Reference 1), and pursuant to 10 CFR 50.55a(a)(3), AmerenUE (Union Electric Company) submitted a request for relief from identified requirements of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, as needed for support of the planned installation of full structural weld overlays for pressurizer nozzle welds at Callaway plant.' The purpose of the overlays is to address, in a pre-emptive manner, primary water stress corrosion cracking concerns that have been identified by the industry for welds associated with Alloy 600/82/182 components exposed to pressurized water reactor primary coolant.

The submitted relief request, which is still under review by the NRC staff, would be applicable to Callaway Plant's Repair/Replacement program (as established by the ASME Section XI Code), and involves utilization of an alternate approach to ASME Section XI requirements in connection with the installation of the weld overlays. From the NRC staff' s review of the request is, several a subsidiary ofAmeren Corporation A04`7

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ULNRC-05395 April 5, 2007 Page 2 questions were identified and then provided to AmerenUE as a request for additional information (RAI). Responses to the NRC's RAI questions were subsequently provided by AmerenUE in a letter dated March 26, 2007 (Reference 2).

On April 4, 2007, the NRC notified AmerenUE that a particular response to one of the RAI questions required clarification. The applicable RAI question, identified as RAI question 8b), asked AmerenUE to address the preservice inspection (PSI) liquid penetrant test (PT) to be performed on the installed weld oeverlays and what acceptance criteria will be used.

In response to the subject RAI question, AmerenUE noted, "All NDE will be performed /2 inch from each side of the overlay weld in accordance with Nonmandatory Appendix Q, Q-4100. The PSI acceptance criteria to be applied will be in accordance with Nonmandatory Appendix Q, Q-4200." The NRC staff asked for clarification of this response with regard to the acceptance criteria to be used for the final PT. AmerenUE hereby notes, pursuant to the requested clarification, that the acceptance criteria for the final PT shall satisfy NB-5300.

AmerenUE notes that no new regulatory.commitments are made in connection with this letter.

For any additional questions regarding this matter, please contact Tom Elwood at 314-554-4593 (acting for the Superintendent, Licensing during the current refueling outage).

Sincerely, David T. Fitzgerald Manager - Regulatory Affairs TBE/

. UL-NRC-05395 April 5, 2007 Page 3 cc: Mr. Bruce S. Mallert Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-7D 1 Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360

,, ULNRC-05395 April 5, 2007 Page 4 bcc: C. D. Naslund S. L. Klang A. C. Heflin D. M. Stepanovic D. T. Fitzgerald S. L. McCracken T. E. Herrmann M. G. Hoehn II L. E. Thibault K. A. Mills G. A. Hughes T. B. Elwood D. E. Shafer G. A. Forster S. L. Gallagher (100) A160.0761 L. M. Belsky (NSRB)

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Send to the following:

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