RS-15-049, Units 1 and 2 - LRA Impact Assessment Associated with Earlier Responses to Set 29 RAI B.2.1 .5-1a, Related to the License Renewal Application

Units 1 and 2 - LRA Impact Assessment Associated with Earlier Responses to Set 29 RAI B.2.1 .5-1a, Related to the License Renewal Application

ML15028A520
Person / Time
Site:	Byron, Braidwood
Issue date:	01/28/2015
From:	Gallagher M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-15-049
Download: ML15028A520 (5)

Text

Michael P. Gallagher Vice President, License Renewal Exelon Generation Exelon Nuclear 200 Exelon Way Kennett Square, PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 RS-15-049 January 28, 2015 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

LRA Impact Assessment Associated with Earlier Responses to Set 29 RAI B.2.1 .5-1a, related to the Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, License Renewal Application

References:

1. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon) to NRC Document Control Desk, dated May 29, 2013, "Application for Renewed Operating Licenses"

2. Letter from Michael P. Gallagher, Exelon, to NRC Document Control Desk, dated November 24, 2014, "Update Associated with Earlier Responses to Set 29 RAI B.2.1.5-1a, related to the Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, License Renewal Application" In Reference 1, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2 (BBS). In Reference 2, Exelon provided to the NRC staff the summary results of the analysis related to control rod drive mechanism (CROM) housing wear in response to request for additional information (RAI) B.2.1.5-1 a.

Exelon participated in the Pressurized Water Reactor Owners Group project, which generically qualified the control rod drive mechanism (CROM) nozzle (housing) with a conservative depth of inside surface wear. This project completed a detailed analysis demonstrating the ASME Code acceptance criteria was met for the hypothetical maximum possible housing wear depth of 0.1075 inches. The final analysis confirmed that the maximum possible housing wear depth of 0.1075 inches will not impact CROM housing integrity at Byron and Braidwood Stations, Units 1

January 28, 2015 U.S. Nuclear Regulatory Commission Page 2 and 2. The summary results of the detailed analysis were communicated to the Staff in Reference 2. The final portion of that letter indicated that the impact on the LRA was under evaluation at that time. This letter provides the outcome of that impact evaluation.

To assess the impact of the change in the fatigue cumulative usage factor as a result of the PWROG CROM Housing Wear Analysis, an analysis to determine an environmentally-assisted fatigue (EAF) cumulative usage factor was performed. The analysis satisfies the Fatigue Monitoring program enhancement for considering the effects of the reactor coolant environment on fatigue, committed in Section A.5 of the LRA (License Renewal Commitment 43), for this component. The results of the EAF analysis determined the EAF cumulative usage factor for sixty years can be maintained less than 1.0. The enhanced Fatigue Monitoring program will monitor transients used in the EAF analysis to maintain the EAF cumulative usage factor for the CROM housing location, with the assumed maximum wear depth, no greater than 1.0 during the period of extended operation.

A comprehensive review of the LRA was conducted to determine if any changes to the LRA were necessary as a result of the CROM Housing wear analysis. The review included, but was not limited to, the following sections: the reactor vessel scoping section (2.3.1.2), aging management review Tables (3.1 .1, 3.1.2-2) with the associated further evaluations, all of section 4 with specific attention to Sections 4.3.1, 4.3.2, 4.3.4, and 4.7, Appendices A and B with specific attention to Sections A.2.1.1, A.2.1.5, A.3.1 .1, B.2.1.1, B.2.1.5, and B.3.1.1. This review concluded that there is no impact to the LRA as a result of the consideration of the CROM Housing Wear Analysis.

The PWROG CROM Housing Wear Analysis (PWROG-14067-P) is not currently part of the Byron and Braidwood licensing basis. A new commitment is added to LRA Appendix A, Section A.5, to incorporate the PWROG CROM Housing Wear Analysis into the Byron and Braidwood licensing basis no later than six months prior to the period of extended operation. The Enclosure provides the new commitment associated with the CROM Housing Wear Analysis.

There are no other new or revised regulatory commitments contained in this letter.

If you have any questions, please contact Mr. Al Fulvio, Manager, Exelon License Renewal, at 610-765-5936.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on / - i.e ' 2ot)

Respectfully, M~---44 Vice President - License Renewal Projects Exelon Generation Company, LLC

January 28, 2015 U.S. Nuclear Regulatory Commission Page 3

Enclosure:

Byron and Braidwood Stations (BBS}, Units 1 and 2, License Renewal Commitment List Update cc: Regional Administrator- NRC Region Ill NRC Project Manager (Safety Review), NRR-DLR NRC Project Manager (Environmental Review), NRR-DLR NRC Senior Resident Inspector, Braidwood Station NRC Senior Resident Inspector, Byron Station NRC Project Manager, NRR-DORL-Braidwood and Byron Stations Illinois Emergency Management Agency - Division of Nuclear Safety

RS-15-049 Enclosure Page 1 of 2 Enclosure Byron and Braidwood Stations (BBS), Units 1 and 2, License Renewal Commitment List Update This Enclosure provides an update to the Byron and Braidwood Stations (BBS), Units 1 and 2, LRA Appendix A, Section A.5 License Renewal Commitment List, documenting that Commitment 49 has been added. Text associated with this addition is shown in bolded italics.

RS-15-049 Enclosure Page 2 of 2 As a result of the completion of activities at Byron and Braidwood Stations, an update is being made to the A.5 License Renewal Commitment List. Text inserted as a result of this update is shown in bolded italics.

A.5 LICENSE RENEWAL COMMITMENT LIST PROGRAM OR IMPLEMENTATION NO. COMMITMENT SOURCE TOPIC SCHEDULE*

Incorporate the analysis performed in PWROG-14067-P, Exelon letter CRDM Housing Wear Revision 0, Generic ASME Code Evaluation of a CRDM No later than six months prior to 49 RS-15-049 Analysis Housing with Inside Surface Wear into the Byron and the period of extended operation.

01/28/2015 Braidwood Units 1 and 2 licensing basis.