RS-14-336, Units 1 and 2 - Supplemental Commitment Related to the October 31, 2014 Response to NRC Request for Additional Information, Set 42, Dated October 10, 2014, Related to License Renewal Application

Units 1 and 2 - Supplemental Commitment Related to the October 31, 2014 Response to NRC Request for Additional Information, Set 42, Dated October 10, 2014, Related to License Renewal Application

ML14330A480
Person / Time
Site:	Byron, Braidwood
Issue date:	11/22/2014
From:	Gallagher M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-14-336
Download: ML14330A480 (16)

Text

A lMichael R Gallagher Gen ratonVice President. License Renewal LA o G n r to Exelon Nuclear 200 Exelon Way Kennett Square. PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.coni rnichaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 RS-14-336 November 22, 2014 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:

Supplemental Commitment related to the October 31, 2014 Response to NRC Request for Additional Information, Set 42, dated October 10, 2014, 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 Lindsay R. Robinson, US NRC to Michael P. Gallagher, Exelon, dated October 10, 2014, "Request for Additional Information for the Review of the Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2, License Renewal Application, Set 42 (TAC NOS. MF1 879, MF1 880, MF1 881, and MF1882)"

3. Letter from Michael P. Gallagher, Exelon to US NRC, dated October 31, 2014, "Response to NRC Request for Additional Information, Set 42, dated October 10, 2014, 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, the NRC requested additional information (RAI) to support staff review of the LRA. In Reference 3, Exelon responded to the Reference 2, Set 42 RAI.

November 22, 2014 U.S. Nuclear Regulatory Commission Page 2 Based on NRC feedback resulting from staff review of the Reference 3 response, Exelon is supplementing the earlier Set 42 response with two additional commitments, for Braidwood only, related to the Flux Thimble Tube Inspection aging management program.

Enclosure A contains a description of and basis for the Flux Thimble Tube Inspection aging management program supplemental commitments.

Enclosure B contains updates to sections of the LRA (except for the License Renewal Commitment List) affected by the response.

Enclosure C provides an update to the License Renewal Commitment List (LRA Appendix A, Section A.5). 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 / 2-i. "20P" Respectfully, Michael P. Gallagher Vice President - License Renewal Projects Exelon Generation Company, LLC

Enclosures:

A. Supplemental Commitments Related to Request for Additional Information RAI B.2.1.24-1a B. Update to Affected LRA Sections C. License Renewal Commitment List Changes cc: Regional Administrator - NRC Region III 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-14-336 Enclosure A Page 1 of 6 Enclosure A Byron and Braidwood (BBS), Units 1 and 2 License Renewal Application Supplemental Commitment Related to Request for Additional Information RAI B.2.1.24-1 a

RS-14-336 Enclosure A Page 2 of 6

==

Introduction:==

During recent refueling outages at Braidwood Station, Units 1 and 2, difficulties in obtaining eddy current testing data as required by the Flux Thimble Tube Inspection program have been experienced. This issue has been entered into the corrective action program for resolution. To address this issue a multi-discipline team has been established to determine the cause of the issue and has developed actions to prevent future recurrence. A summary of the planned corrective actions to address this issue was provided in the response to RAI B.2.1.24-1 a. Based on these corrective actions there is confidence that the issue will be resolved and the required data obtained. Furthermore, the program currently accounts for situations when eddy current testing data cannot be obtained by replacing or removing from service flux thimble tubes which cannot be shown by analysis to be satisfactory for continued service. This is consistent with the recommendations in GALL Report AMP XI.M37, Element 7.

To provide further assurance that the intended function of the flux thimble tubes (i.e., reactor coolant pressure boundary) will be maintained if future difficulties in obtaining eddy current testing data are encountered at Braidwood Station, the Flux Thimble Tube Inspection (B.2.1.24) aging management program will be enhanced as follows:

1. For Braidwood Unit 1:

a. The 17 Braidwood Station, Unit 1 flux thimble tubes that exhibited indications of wear during eddy current testing performed during Al R15 Refueling Outage (Fall 2010),

will be replaced or removed from service during Al R18 Refueling Outage (Spring 2015), unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 8 (K-6), 9 (H-1 1), 12 (E-9), 14 (H-4),

18 (L-11), 19 (L-5), 21 (E-11), 23 (D-10), 36 (J-14), 37 (P-9), 41 (N-4), 44 (R-8), 45 (N-13), 48 (P-4), 54 (A-11), 55 (N-14))

b. The remaining Braidwood Station, Unit 1 flux thimble tubes, not replaced during Al R1 8, will be replaced or removed from service during Al R1 9 Refueling Outage (Fall 2016), unless eddy current data is obtained as required by the Flux Thimble Inspection Tube program.

c. Following Al R19, any Braidwood Station, Unit 1 flux thimble tube will be replaced every three (3) refueling outages or removed from service if eddy current data is not obtained in accordance with the Flux Thimble Tube Inspection program.

2. For Braidwood Unit 2:

a. The 29 Braidwood Station, Unit 2 flux thimble tubes that exhibited indications of wear during eddy current testing performed during A2R1 5 Refueling Outage (Spring 2011) and not replaced during A2R17 Refueling Outage (Spring 2014), will be replaced or removed from service during A2R18 Refueling Outage (Fall 2015), unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program.

(Flux thimble tubes 1 (J-8), 4 (H-6), 5 (F-8), 6 (J-10), 7 (F-7), 9 (H-1 1), 10 (L-8), 11 (G-5), 18 (L-11), 22 (K-12), 23 (D-10), 24 (H-13), 25 (N-8), 26 (H-3), 27 (C-8), 29 (N-6), 32 (L-13), 33 (C-5), 34 (H-2), 36 (J-14), 37 (P-9), 40 (F-14), 41 (N-4), 42 (D-3), 45 (N-13), 46 (J-l), 50 (R-6), 52 (L-15), 56 (N-2))

RS-1 4-336 Enclosure A Page 3 of 6

b. The remaining Braidwood Station, Unit 2 flux thimble tubes, not replaced during A2R17 or A2R18, will be replaced or removed from service during A2R19 Refueling Outage (Spring 2017), unless eddy current data is obtained as required by the Flux Thimble Inspection Tube program.

c. Following A2R1 9, any Braidwood Station, Unit 2 flux thimble tube will be replaced every three (3) refueling outages or removed from service if eddy current data is not obtained in accordance with the Flux Thimble Tube Inspection program.

The enhancement for both Braidwood Unit 1 and Braidwood Unit 2 will ensure that the currently installed flux thimble tubes will be conservatively replaced or removed from service if eddy current testing data is not obtained for the individual tubes as required by the program. In addition, part (c) of the enhancements ensures that if difficulties in obtaining eddy current testing data are encountered in the future, then the tubes for which eddy current testing data is not obtained will be replaced such that the intended function of the flux thimble tubes is maintained.

The following discussion provides the basis for the replacement frequency for flux thimble tubes if eddy current testing data is not obtained as required by the program. In addition, a summary of the basis for continued operation of the currently installed flux thimble tubes to the next refueling outage (for tubes that had indications of wear in Al R15 or A2R15) or to the subsequent refueling outage (for tubes that did not have indications of wear in Al R1 5 or A2R15) is provided.

Justification for Replacement Frequency:

The response to RAI B.2.1.24-1a is supplemented to enhance the Flux Thimble Tube Inspection (B.2.1.24) aging management program. The enhancement to the program will require any Braidwood Station flux thimble tube be replaced every three (3) refueling outages or removed from service if eddy current data is not obtained in accordance with the Flux Thimble Tube Inspection program. To determine the appropriate replacement frequency, the historic eddy current testing data over the first 15 refueling cycles for both units, when eddy current testing data was successfully obtained in accordance with the program requirements, was reviewed. Based on this review, none of the 116 flux thimble tubes at Braidwood Units 1 and 2 were required to be replaced due to age-related degradation (i.e., wear due to flow induced vibration) in less than four (4) refueling cycles and in fact, the majority of the original flux thimble tubes have remained in service through the first 15 refueling cycles. Therefore, it is concluded that replacements of flux thimble tubes on a three (3) refueling cycle frequency, if eddy current testing data is not obtained in accordance with the Flux Thimble Tube Inspection program, is very conservative and will ensure that flux thimble tubes are replaced well before age-related degradation challenges the intended function of the flux thimble tubes.

During recent refueling outages, indications of "higher than expected wear" have been entered into the corrective action program. The issue of higher than expected wear was addressed in the response to RAI B.2.1.24-1, request 1, in Exelon letter RS-14-165, dated June 9, 2014. As explained in the response, the higher than expected wear was measured after a flux thimble tube had been in service for only one (1) cycle of operation. Although

RS-14-336 Enclosure A Page 4 of 6 this issue was characterized as "higher than expected wear," as described in WCAP-1 2866, Bottom Mounted InstrumentationFlux Thimble Tube Wear, the highest wear rates are experienced during the first cycle of operation and, therefore, higher wear rates during the initial cycle of a newly installed flux thimble tube are expected. The operating experience evaluated in WCAP-1 2866 indicates that the wear rate decreases substantially with continued service.

In each case where flux thimble tube locations were identified as having higher than expected wear after only one (1) cycle of operation, the previously installed flux thimble tube had remained in service for 13 cycles before being replaced. Subsequent eddy current data (second cycle data) was obtained on some of these and confirmed that wear had stabilized and the wear rate had decreased significantly, consistent with the operating experience evaluated in WCAP-12866. Therefore, a replacement frequency of three (3) refueling outages is sufficient to ensure flux thimble tube integrity is maintained. In one instance, a flux thimble tube experienced a one-time increase in wear, greater than its normal wear.

The increased wear rate (11 % per cycle) was not excessive and subsequent eddy current data confirmed the wear rate returned to normal. In addition, this flux thimble tube remained in service for 16 cycles until replacement was required. Therefore, a replacement frequency of three (3) refueling outages is sufficient to ensure flux thimble tube integrity is maintained.

In conclusion, a three (3) refueling cycle replacement frequency is conservative even when the evaluation accounts for instances of "higher than expected wear" that have been experienced at Braidwood Station.

Tube Replacements to be Performed Next Refueling Outaqe (Unit 1 - Spring 2015; Unit 2 Fall 2015) if ECT Data is not Obtained:

To address the flux thimble tubes that are currently in service, the program is enhanced to require that tubes that exhibited indications of wear during eddy current testing performed during the 15 1h refueling outage at both Unit 1 and Unit 2, will be replaced or removed from service during the next scheduled refueling outage, unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program. For Unit 1, 17 flux thimble tubes exhibited indications of wear between 17% to 42% during eddy current testing performed during the 15 1h refueling outage (Fall 2010). These flux thimble tubes will be replaced or removed from service in the Spring 2015 refueling outage unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program. For Unit 2, 29 flux thimble tubes exhibited indications of wear between 12% to 44% during eddy current testing performed during the 15 th refueling outage (Spring 2011). These flux thimble tubes will be replaced or removed from service in the Fall 2015 refueling outage unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program. Five (5) other flux thimble tubes at Unit 2 also exhibited indications of wear during eddy current testing performed during the 15 1h refueling outage and have subsequently been replaced, as described below. Since existing analysis has determined that a flux thimble tube is capable of performing its intended function with up to 85% wall loss, the indications of wear on the flux thimble tubes that remain in service (between 17% and 42% on Unit 1 and between 12% and 44% on Unit 2) are well within acceptable parameters.

During the most recent refueling outages for both Unit 1 and Unit 2, an evaluation was completed to determine if the installed flux thimble tubes could be shown to be satisfactory for continued operation based on conservative projections utilizing historic testing data. Flux thimble tubes that could not be analytically shown to be satisfactory for continued service

RS-14-336 Enclosure A Page 5 of 6 were replaced or removed from service. At Braidwood Unit 1, two (2) flux thimble tubes were removed from service by capping during the most recent refueling outage. These two (2) flux thimble tubes will be replaced during the upcoming Spring 2015 refueling outage. At Braidwood Unit 2, seven (7) flux thimble tubes were replaced during the most recent refueling outage (Spring 2014). Although five (5) of these seven (7) flux thimble tubes exhibited indications of wear during eddy current testing performed during the 15 th refueling outage, these five (5) tubes will not be replaced or removed from service in the upcoming Fall 2015 refueling outage since, as discussed above, a review of operating experience demonstrates that newly installed flux thimble tubes can remain in service more than three (3) refueling outages. These five (5) flux thimble tubes will be replaced during the Fall 2018 refueling outage if eddy current data is not obtained in accordance with a three (3) refueling cycle replacement frequency specified in part (c) of the enhancements.

Tube Replacements to be Performed in Subsequent Refueling Outages (Unit 1 - Fall 2016; Unit 2 - Spring 2017 or Fall 2018) if ECT Data is not Obtained:

To address the remaining flux thimble tubes that did not exhibit indications of wear during eddy current testing performed during the 15 th refueling outage at both Unit 1 and Unit 2, the program will require tube replacement in subsequent refueling outages (Fall 2016 for Unit 1 and Spring 2017 for Unit 2) unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program.

At Braidwood Unit 1, the remaining 41 flux thimble tubes that did not exhibit indications of wear in A1R15 refueling outage (Fall 2010) will be replaced or removed from service in the subsequent refueling outage (Fall 2016) unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program. Of these 41 flux thimble tubes, 37 had each been in service for six (6) or more refueling cycles when eddy current testing was performed in the 15 1h refueling outage. There is reasonable assurance that the intended function of these tubes will be maintained through the Fall 2016 refueling outage since these tubes exhibited no indications of wear after being in service for six (6) or more refueling cycles.

The remaining four (4) flux thimble tubes had been replaced in the prior outage due to issues other than wear. The operating experience for these four (4) flux thimble tubes indicates that significant wear has not occurred at these locations prior to the replacement of the tube. Based on this it is concluded that the 41 flux thimble tubes that will not be replaced or removed from service in the upcoming Spring 2015 refueling outage are satisfactory for continued service until the following refueling outage.

At Braidwood Unit 2, the remaining 29 flux thimble tubes will be replaced or removed from service in subsequent refueling outages (Spring 2017 or Fall 2018) unless eddy current data is obtained as required by the Flux Thimble Tube Inspection program. Of these 29 flux thimble tubes, seven (7) were replaced in the most recent refueling outage (Spring 2014).

As discussed above, a review of operating experience demonstrates that newly installed flux thimble tubes remain satisfactory for continued service for more than three (3) refueling outages and, therefore, these seven (7) flux thimble tubes will be replaced in the Fall 2018 refueling outage in accordance with part (c) of the enhancements. The remaining 22 flux thimble tubes had each been in service for six (6) or more refueling cycles when eddy current testing was performed in the 15 1h refueling outage. There is reasonable assurance that the intended function of these tubes will be maintained to the Spring 2017 refueling outage since these tubes exhibited no indications of wear after being in service for six (6) or more refueling cycles.

RS-14-336 Enclosure A Page 6 of 6

==

Conclusion:==

In conclusion, with the enhancements to the Flux Thimble Tube Inspection (B.2.1.24) aging management program contained in this submittal, there is reasonable assurance that the intended function of Braidwood Station, Units 1 and 2 flux thimble tubes will be maintained if future difficulties in obtaining eddy current testing data is experienced. Replacement of flux thimble tubes when eddy current testing data is not obtained is consistent with the guidance provided in GALL Report AMP XI.M37.

RS-14-336 Enclosure B Page 1 of 5 Enclosure B Byron and Braidwood Stations, Units 1 and 2 License Renewal Application (LRA) Updates Note: To facilitate understanding, portions of the original LRA have been repeated in this Enclosure, with revisions indicated. Existing LRA text is shown in normal font. Changes are highlighted with bolded italicsfor inserted text.

RS-14-336 Enclosure B Page 2 of 5 As a result of the response provided in Enclosure A of this letter, LRA Appendix A, Section A. 1.1, page A-6 and A.2.1.24, page A-28, are revised as shown below. Additions are indicated with bolded italics.

A.1.1 NUREG-1801 Chapter XI Aging Management Programs The Byron and Braidwood NUREG-1801 Chapter XI Aging Management Programs (AMPs) are described in this section. The AMPs are either existing, existing with enhancements (enhanced) or new.

The following list reflects the status of these programs at the time of the License Renewal Application (LRA) submittal. Commitments for program additions and enhancements are identified in the Appendix A.5 License Renewal Commitment List.

24. Flux Thimble Tube Inspection (Section A.2.1.24) [Existing - Requires Enhancement]

A.2.1.24 Flux Thimble Tube Inspection The Flux Thimble Tube Inspection aging management program is an existing condition monitoring program that manages the loss of material in flux thimble tubes due to wear (i.e., wall thinning). Flux thimble tubes, which provide a path for the in-core neutron flux monitoring system detectors, establish part of the reactor coolant pressure boundary and are subject to flow-induced fretting which causes wear. The program uses the non-destructive examination methodology of eddy current testing to periodically inspect the full length of all flux thimble tubes, which encompasses the path from the reactor vessel instrument nozzle to the fuel assembly instrument guide.

The results of the periodic eddy current testing are evaluated and trended to determine if corrective actions are required or if the inspection frequency needs to be changed to ensure reactor coolant pressure boundary integrity is maintained. Corrective actions include flux thimble tube limited repositioning (one-time), replacement, or isolation (removal from service).

The Flux Thimble Tube Inspection program implements the recommendations of NRC IE Bulletin 88-09, "Thimble Tube Thinning in Westinghouse Reactors." This existing aging management program will continue to be implemented during the period of extended operation.

The Flux Thimble Tube Inspection aging managementprogram will be enhanced as follows:

1. For Braidwood Unit 1:

a. The 17 Braidwood Station, Unit 1 flux thimble tubes that exhibited indicationsof wear during eddy current testing performed during A 1R15 Refueling Outage (Fall2010), will be replaced or removed from

RS-14-336 Enclosure B Page 3 of 5 service during A 1R18 Refueling Outage (Spring2015), unless eddy current datais obtainedas requiredby the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 8 (K-6), 9 (H-11), 12 (E-9), 14 (H-4), 18 (L- 11), 19 (L-5), 21 (E- 11), 23 (D-10), 36 (J-14), 37 (P-9), 41 (N-4), 44 (R-8), 45 (N-13), 48 (P-4), 54 (A- 11), 55 (N-14))

b. The remainingBraidwood Station, Unit 1 flux thimble tubes, not replacedduring A 1R18, will be replaced or removed from service duringA 1R19 Refueling Outage (Fail2016), unless eddy currentdata is obtainedas requiredby the Flux Thimble Inspection Tube program.

c. Following A 1R19, any Braidwood Station, Unit 1 flux thimble tube will be replacedevery three (3) refueling outages or removed from service if eddy currentdata is not obtainedin accordancewith the Flux Thimble Tube Inspection program.

2. For Braidwood Unit 2:

a. The 29 BraidwoodStation, Unit 2 flux thimble tubes that exhibited indicationsof wear during eddy currenttesting performed during A2R15 Refueling Outage (Spring 2011) and not replaced during A2R17 Refueling Outage (Spring2014), will be replaced or removed from service during A2R18 Refueling Outage (Fail2015), unless eddy current data is obtainedas requiredby the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 4 (H-6), 5 (F-8), 6 (J-10), 7(F-7), 9(H-11), 10(L-8), 11 (G-5), 18(L-11), 22(K-12), 23(D-10),

24 (H-13), 25 (N-8), 26 (H-3), 27 (C-8), 29 (N-6), 32 (L-13), 33 (C-5), 34 (H-2), 36 (J-14), 37 (P-9), 40 (F-14), 41 (N-4), 42 (D-3), 45 (N-13), 46 (J-1), 50 (R-6), 52 (L- 15), 56 (N-2))

b. The remaining BraidwoodStation, Unit 2 flux thimble tubes, not replaced duringA2R17 or A2R18, will be replacedor removed from service during A2R19 Refueling Outage (Spring 2017), unless eddy current data is obtainedas requiredby the Flux Thimble Inspection Tube program.

c. Following A2R19, any Braidwood Station, Unit 2 flux thimble tube will be replaced every three (3) refueling outages or removed from service if eddy current data is not obtainedin accordance with the Flux Thimble Tube Inspection program.

These enhancements will be implemented in accordance with the schedule specified in the enhancement.

RS-14-336 Enclosure B Page 4 of 5 As a result of the response provided in Enclosure A of this letter, LRA Appendix B, Sections B.1.5, page B-10 and B.2.1.24, page B-153, are revised as shown below. Additions are indicated with bolded italics; deletions are shown with stiketlweughs.

B.1.5 NUREG-1801 CHAPTER XI AGING MANAGEMENT PROGRAMS The following NUREG-1801 Chapter Xl AMPs are described in Section B.2 of this appendix as indicated. Programs are identified as either existing or new to Byron and Braidwood. All programs are or will be consistent with programs discussed in NUREG-1801.

24. Flux Thimble Tube Inspection (Section B.2.1.24) [Existing - Requires Enhancement]

B.2.1.24 Flux Thimble Tube Inspection Enhancements Nee.

The following enhancements will be implemented in the following program elements:

1. For Braidwood Unit 1:

a. The 17 Braidwood Station, Unit 1 flux thimble tubes that exhibited indicationsof wear during eddy current testing performed during A 1R15 Refueling Outage (Fall2010), will be replaced or removed from service during A 1R18 Refueling Outage (Spring 2015), unless eddy current data is obtained as requiredby the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 8 (K-6), 9 (H-11), 12 (E-9), 14 (H-4), 18 (L- 11), 19 (L-5), 21 (E-11), 23 (D-10), 36 (J-14), 37 (P-9), 41 (N-4), 44 (R-8), 45 (N-13), 48 (P-4), 54 (A-11), 55 (N- 14))

b. The remaining BraidwoodStation, Unit 1 flux thimble tubes, not replacedduring A 1R18, will be replaced or removed from service during A 1R19 Refueling Outage (Fall2016), unless eddy currentdata is obtainedas requiredby the Flux Thimble Inspection Tube program.

c. Following A 1R19, any Braidwood Station, Unit 1 flux thimble tube will be replaced every three (3) refueling outages or removed from service if eddy currentdata is not obtainedin accordancewith the Flux Thimble Tube Inspection program.

ProgramElement Affected: CorrectiveActions (Element 7)

RS-14-336 Enclosure B Page 5 of 5

2. For Braidwood Unit 2:

a. The 29 BraidwoodStation, Unit 2 flux thimble tubes that exhibited indicationsof wear during eddy current testing performed during A2R15 Refueling Outage (Spring 2011) and not replaced during A2R17 Refueling Outage (Spring2014), will be replaced or removed from service during A2R18 Refueling Outage (Fall 2015), unless eddy current data is obtainedas requiredby the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 4 (H-6), 5 (F-8), 6 (J-10), 7(F-7), 9 (H-11), 10 (L-8), 11 (G-5), 18 (L-11), 22 (K-12), 23 (D-10),

24 (H-13), 25 (N-8), 26 (H-3), 27 (C-8), 29 (N-6), 32 (L-13), 33 (C-5), 34 (H-2), 36 (J-14), 37 (P-9), 40 (F-14), 41 (N-4), 42 (D-3), 45 (N-13), 46 (J-1),

50 (R-6), 52 (L-15), 56 (N-2))

b. The remainingBraidwood Station, Unit 2 flux thimble tubes, not replacedduring A2R17 or A2R 18, will be replacedor removed from service during A2R19 Refueling Outage (Spring 2017), unless eddy current data is obtainedas requiredby the Flux Thimble Inspection Tube program.

c. Following A2R19, any Braidwood Station, Unit 2 flux thimble tube will be replaced every three (3) refueling outages or removed from service if eddy current data is not obtained in accordance with the Flux Thimble Tube Inspection program.

ProgramElement Affected: CorrectiveActions (Element 7)

RS-14-336 Enclosure C Page 1 of 3 Enclosure C Byron and Braidwood Stations (BBS) Units 1 and 2 License Renewal Commitment List Changes This Enclosure identifies commitments made in this document and is an update to the Byron and Braidwood Station (BBS) LRA Appendix A, Table A.5, License Renewal Commitment List.

Any other actions discussed in the submittal represent intended or planned actions and are described to the NRC for the NRC's information and are not regulatory commitments. Changes to the BBS LRA Appendix A, Table A.5 License Renewal Commitment List are as a result of this submittal.

Notes:

" To facilitate understanding, portions of the original License Renewal Commitment List have been repeated in this Enclosure, with revisions indicated.

" Existing LRA text is shown in normal font. Changes are highlighted with bold italics for inserted text and 64ikethweughs for deleted text.

RS-14-336 Enclosure C Page 2 of 3 As a result of the response provided in Enclosure A of this letter, LRA Appendix A, Table A.5 License Renewal Commitment List, Item 24 on page A-80, is revised as shown below. The correspondence that led to this commitment modification is listed in the "SOURCE" column. Any other actions described in this submittal represent intended or planned actions. They are described for the NRC's information and are not regulatory commitments. Additions are indicated with bolded italics; deletions are shown with 6',t ÷ ,*e,-ughs.

NO. PROGRAM OR COMMITMENT IMPLEMENTATION SOURCE TOPIC COMMITMENTSCHEDULE ____

24 Flux Thimble Tube Existing prog.rm is;creditod. Ongoing Section A.2.1.24 Inspection Flux Thimble Tube Inspection is an existing programthat will be Schedule for flux thimble Exelon letter enhanced as follows: tube replacement activities RS-14-336 identified in commitment. 11/22/2014

1. ForBraidwood Unit I (Note 3):

a. The 17 Braidwood Station, Unit 1 flux thimble tubes that exhibited indicationsof wear during eddy current testing performed during A 1R15 Refueling Outage (Fall 2010), will be replaced or removed from service during A iR18 Refueling Outage (Spring2015), unless eddy current datais obtainedas requiredby the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 8 (K-6), 9 (H-11), 12 (E-9), 14 (H-4), 18 (L- 11), 19 (L-5), 21 (E-1 1), 23 (D-10), 36 (J-14), 37 (P-9), 41 (N-4), 44 (R-8), 45 (N-13), 48 (P-4), 54 (A- 11), 55 (N-14))

b. The remaining BraidwoodStation, Unit 1 flux thimble tubes, not replaced during A 11R18, will be replaced or removed from service during A 1R19 Refueling Outage (Fall2016), unless eddy current data is obtained as requiredby the Flux Thimble Inspection Tube program.

c. Following A 1R19, any BraidwoodStation, Unit 1 flux thimble tube will be replacedevery three (3) refueling outages or removed from service if eddy currentdata is not obtainedin accordancewith the Flux Thimble Tube Inspection program.

RS-14-336 Enclosure C Page 3 of 3 NO. PROGRAM OR COMMITMENT IMPLEMENTATION SOURCE TOPIC SCHEDULE

2. For Braidwood Unit 2 (Note3):

a. The 29 Braidwood Station, Unit 2 flux thimble tubes that exhibited indications of wear during eddy current testing performed during A2R15 Refueling Outage (Spring 2011) and not replaced during A2R17 Refueling Outage (Spring 2014), will be replaced or removed from service during A2R18 Refueling Outage (Fall2015),

unless eddy current data is obtainedas requiredby the Flux Thimble Tube Inspection program. (Flux thimble tubes 1 (J-8), 4 (H-6), 5 (F-8), 6 (J-10), 7 (F-7), 9 (H-1 1), 10 (L-8), 11 (G-5), 18 (L-11), 22 (K-12), 23 (D-10), 24 (H-13),

25 (N-8), 26 (H-3), 27 (C-8), 29 (N-6), 32 (L-13), 33 (C-5), 34 (H-2), 36 (J-14), 37 (P-9), 40 (F-14), 41 (N-4), 42 (D-3), 45 (N-13), 46 (J-1), 50 (R-6), 52 (L-15), 56 (N-2))

b. The remaining Braidwood Station, Unit 2 flux thimble tubes, not replacedduring A2R17 or A2R18, will be replaced or removed from service during A2R19 Refueling Outage (Spring 2017), unless eddy current data is obtainedas requiredby the Flux Thimble Inspection Tube program.

C. Following A2R19, any Braidwood Station, Unit 2 flux thimble tube will be replaced every three (3) refueling outages or removed from service if eddy current data is not obtainedin accordancewith the Flux Thimble Tube Inspection program.