RS-18-095, Response to Request for Additional Information Regarding Braidwood Station Fourth Lnservice Inspection Interval Relief Request 14R-03

Response to Request for Additional Information Regarding Braidwood Station Fourth Lnservice Inspection Interval Relief Request 14R-03

ML18212A352
Person / Time
Site:	Braidwood
Issue date:	07/31/2018
From:	Gullott D Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-18-095
Download: ML18212A352 (3)

Text

RS-18-095 10 CFR 50.55a July 31, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-72 and NPF-77 N RC Docket Nos. STN 50-456 and STN 50-457

Subject:

Response to Request for Additional Information Regarding Braidwood Station Fourth lnservice Inspection Interval Relief Request 14R-03

References:

1) Letter from D. M. Gullatt (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Braidwood Station, Units 1 and 2, Relief Requests 11 Associated with the Fourth lnservice Inspection lnterval, dated March 19, 2018 (ADAMS Accession No. ML18078A185)

2) Letter from D. M. Gullatt (Exelon Generation Company, LLC) to U.S. Nuclear 11 Regulatory Commission, Braidwood Station, Units 1 and 2, Supplement to Relief Request 14R-03 Associated with the Fourth lnservice Inspection 11 lnterval, dated May 3, 2018 (ADAMS Accession No. ML18124A154)

3) Email from J. Wiebe (U.S. Nuclear Regulatory Commission) to L.A. Simpson (Exelon Generation Company, LLC), "Preliminary RAls for Braidwood Relief 11 Request 14R-05, dated July 11, 2018 By letter dated March 19, 2018 (Reference 1), as supplemented by letter dated May 3, 2018 (Reference 2), Exelon Generation Company, LLC (EGG) submitted a request in accordance with Paragraph 50.55a(z)(2) of Title 1O of the Code of Federal Regulations (10 CFR) for a proposed 11 alternative to the requirements of Section XI, Rules for lnservice Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) for Braidwood Station, Units 1 and 2. The EGG proposed alternative, 14R-03, would permit performance of an alternative repair of leaking control rod drive mechanism canopy seal welds in lieu of specified ASME Code requirements.

In Reference 3, the NRC requested additional information to complete its review of Relief Request 14R-03. The requested information is provided in the attachment of this letter.

There are no regulatory commitments contained within this letter.

July 31, 2018 U.S. Nuclear Regulatory Commission Page 2 Should you have any questions concerning this letter, please contact Ms. Lisa A. Simpson at (630) 657-2815.

Respectfully, David M. Gullatt Manager - Licensing Exelon Generation Company, LLC

Attachment:

Response to Request for Additional Information cc: NRC Regional Administrator, Region Ill NRC Senior Resident Inspector, Braidwood Station NRC Senior Resident Inspector, Byron Station Illinois Emergency Management Agency - Division of Nuclear Safety

ATTACHMENT Response to Request for Additional Information By letter dated March 19, 2018 (ADAMS Accession No. ML18078A185), as supplemented by letter dated May 3, 2018 (ADAMS Accession No. ML18124A154), Exelon Generation Company, LLC (EGG) submitted a request in accordance with Paragraph 50.55a(z)(2) of Title 1O of the Code of Federal Regulations (1 O CFR) for a proposed alternative to the requirements of 11 11 Section XI, Rules for lnservice Inspection of Nuclear Power Plant Components, of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) for Braidwood Station, Units 1 and 2. The proposed alternative, 14R-03, would permit performance of an alternative repair of leaking control rod drive mechanism canopy seal welds in lieu of specified ASME Code requirements.

In an email dated July 11, 2018, the U.S. Nuclear Regulatory Commission (NRG) requested additional information to complete its review of Relief Request 14R-03. The NRC's request for additional information (RAI) and EGC's response are provided below.

NRC RAI 11 11 Section 5, Proposed Alternative and Basis for Use, of the licensee's proposed alternative 11 states, The CROM canopy seal weld flaws will not be removed, but an analysis of the repaired weldment will be performed, prior to entering Mode 4, to assure that the remaining flaw will not 11 propagate unacceptably. In a previous relief request dated September 19, 2013 (ADAMS Accession No. ML13263A372), with a supplement dated January 24, 2014 (ADAMS Accession No. ML14024A588), the licensee stated that it will use applicable portions of ASME Code Case 11 N-504-4, Alternative Rules for Repair of Class 1, 2, and 3, Austenitic Stainless Steel Piping, 11 Section XI, Division 1, for repair by weld overlay to provide a new leakage barrier and that the remaining flaw analysis would be using Paragraph (g) of ASME Code Case N-504-4. Provide a description of methods to be used for the current design of the weld overlay and perform the flaw growth analysis and a basis for why the chosen methods are acceptable.

EGC Response As referenced in the NRG RAI, EGG submitted Braidwood relief request 13R-11 by letter dated September 19, 2013 (ADAMS Accession No. ML13263A372), as supplemented by letter dated January 24, 2014 (ADAMS Accession No. ML14024A588), which proposed an alternative method of repair and nondestructive examination for control rod drive mechanism (CROM) canopy seal welds. The alternative repair involved the use of applicable portions of ASME 11 Code Case N-504-4, Alternative Rules for Repair of Classes 1, 2, and 3 Austenitic Stainless 11 Steel Piping,Section XI, Division 1. Relief request 13R-11 was authorized for the Braidwood third 10-year ISi interval of the Braidwood Station, Units 1 and 2, lnservice Inspection Program by NRG letter dated April 28, 2014 (ADAMS Accession No ML14084A549).

11 ASME Section XI Code Case N-504-4 was incorporated into Nonmandatory Appendix Q, Weld 11 Overlay Repair of Classes 1, 2, and 3 Austenitic Stainless Steel Piping Weldments, with the 2007 Edition of ASME Section XI. Weld overlays are addressed by Nonmandatory Appendix Q, which has been endorsed by the NRG. Since the Code of record for Braidwood, Units 1 and 2 fourth 10-year lnservice Inspection interval is the 2013 Edition, EGG would be performing required repairs to the reactor CROM canopy seal welds in accordance with ASME Section XI, Nonmandatory Appendix Q, not ASME Code Case N-504-4.

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