Exelon Generation® Exelon Nuclear 200 Exelon Way Fax · Michael P. Gallagher Exelon Generation® Vice President. License Renewal Exelon Nuclear 200 Exelon Way RS-14-169 June 16,

Michael P. Gallagher

Exelon Generation® Vice President. License Renewal Exelon Nuclear

200 Exelon Way

RS-14-169

June 16, 2014

Kennett Square. PA 19348

610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com

[email protected]

10 CFR 50 10 CFR 51 10 CFR 54

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

References:

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

Responses to NRC Requests for Additional Information, Set 27, dated May 21 , 2014, and Correction of Previously Submitted Information related to the Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2, License Renewal Application

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 May 21 , 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 27 (TAC NOS. MF1879, MF1880, MF1881, and MF1882)"

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 to support staff review of the LRA.

Enclosure A contains the responses to these requests for additional information.

Enclosure B contains updates to sections of the LRA (except for the License Renewal Commitment List) affected by the responses. As explained further in Enclosure B, the updates to LRA Sections A.2.1.16 and B.2.1.16 reflect these LRA sections as revised by all previous RAI responses associated with the Fire Water System aging management program.

June 16, 2014 U.S. Nuclear Regulatory Commission Page 2

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.

Enclosure D provides the current revision of the Plant Specific Notes following Table 3.1.2-4, Steam Generators - Summary of Aging Management Evaluation. Exelon letter RS-14-130, dated May 12, 2014 inadvertently omitted the revision to Plant Specific Note 4 that had previously been made in Exelon letter RS-14-051, dated February 27, 2014. See Enclosure D for additional details.

Enclosure D also provides the current revision of LRA Sections A.3.1.1 and B.3.1.1, both associated with the Fatigue Monitoring aging management program, including all modifications made in previous RAI responses. The versions of these documents last submitted to the NRC, in Exelon letter RS-14-150, dated May 23, 2014, inadvertently omitted text that had previously been added in Exelon letter RS-14-002, dated January 13, 2014. See Enclosure D for additional details.

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

Respectfully,

Michael P. Gallagher Vice President - License Renewal Projects Exelon Generation Company, LLC

Enclosures: A. Responses to Requests for Additional Information B. Updates to affected LRA sections C: License Renewal Commitment List Changes D: Latest Versions of LRA Sections A.3.1.1 and B.3.1 .1

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-14-169 Enclosure A Page 1 of 9

Enclosure A

Byron and Braidwood Stations (BBS), Units 1 and 2

License Renewal Application

Responses to Requests for Additional Information

RAI B.2.1.16-1a RAI B.2.1.16-1b RAI 3.5.2.10-1


RAI B.2.1.16-1a Applicability: Byron Station (Byron) and Braidwood Station (Braidwood), all units Background: The applicant’s response, dated March 13, 2014, to Request 1 for request for additional information (RAI) B.2.1.16-1 states that the Fire Water System program will be enhanced to include non-destructive examinations (NDE) “capable of detecting internal flow blockage (e.g., digital radiography) or internal visual inspections.” The response also states that inspections will be performed by opening a flushing connection at the end of one [emphasis added by NRC] main in each structure containing in-scope water-based fire suppression systems. Issue: The staff notes that the National Fire Protection Association (NFPA) 25, Section 14.2.2, requires an internal inspection of every other wet pipe system (in buildings with multiple wet pipe systems) and that the alternate systems (not inspected during the previous inspection) be inspected during the next inspection. Since the response only stated that one main in each structure will be opened, it is not clear whether there are multiple wet pipe systems in any of the structures containing in-scope fire water systems and, if so, whether all wet pipe systems will be inspected as stated in NFPA 25. The staff also notes that LR-ISG-2012-02 AMP XI.M27 Table 4a limits the alternative NDE methods, which are permitted by NFPA 25, Sections 14.2.1.1 and 14.3.2.3, to those that can ensure that flow blockage will not occur. Because of its similarity to raw water applications in fire water systems, the staff further notes that the Electric Power Research Institute (EPRI) TR-102063, “Guide for the Examination of Service Water System Piping,” cites radiography as an effective NDE method capable of measuring the extent of occlusions or biofouling conditions. Although the EPRI guide includes ultrasonic testing, the discussion of its capability is limited to wall thickness measurement. Because the response proposes digital radiography as an example and not the only method, it was not clear how other NDE methods, if used, would be demonstrated to be capable of detecting flow blockage. Request:

1. State whether there are multiple wet pipe systems in any of the structures containing in-scope fire water systems and, if there are, confirm that internal inspections will be conducted as stated in NFPA 25, Section 14.2.2, or provide the basis for not conducting the internal inspections on every other wet pipe system every five years.

2. If NDE methods other than digital radiography are used, state how the other NDE methods will be demonstrated to be capable of detecting flow blockage.


Exelon Response:

1. There are multiple wet pipe sprinkler systems in some of the structures containing in-scope fire water systems at Byron and Braidwood. The Fire Water System (B.2.1.16) aging management program will be revised to require internal visual inspections or radiographic testing at the end of one (1) fire main and the end of one (1) branch line on half of the wet pipe sprinkler system every five (5) years. The wet pipe sprinkler systems that are not inspected during a five (5) year period will be inspected during the subsequent five (5) year period. LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B to reflect this change. LRA Table A.5, Item 16 is revised as shown in Enclosure C to reflect this change.

2. The Fire Water System (B.2.1.16) aging management program will be revised to specify that radiographic testing is the only nondestructive testing technique approved for detection of flow blockage in the Fire Protection System. LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B to reflect this change. LRA Table A.5, Item 16 is revised as shown in Enclosure C to reflect this change.


RAI B.2.1.16-1b Applicability: Byron and Braidwood Background: RAI B.2.1.16-1 requested that either: (a) it is confirmed that follow-up volumetric examinations will be conducted whenever internal fire water system visual inspections detect surface irregularities indicative of material loss below nominal wall thickness [emphasis added by NRC]; or (b) the bases be provided for why the visual inspection alone will provide reasonable assurance that the current licensing basis intended functions of in-scope components will be met. The applicant’s response, dated March 13, 2014, to RAI B.2.1.16-1 states that noticeable deposits in excess of a normal oxide layer, which could be indicative of wall loss below nominal, are documented; inspection results that are unusual or unexpected (e.g., surface irregularities indicative of significant loss of material [emphasis added by NRC]) are documented in the corrective action program for evaluation; and, based on the results of the evaluation, appropriate corrective actions are taken including repair, replacement, or follow-up volumetric examinations to quantify the remaining wall thickness, as applicable. Issue: The staff noted that LR-ISG-2012-02 AMP XI.M27 states that, “[i]nternal visual inspections used to detect loss of material are capable of detecting surface irregularities that could be indicative of wall loss below nominal pipe wall thickness due to corrosion and corrosion product deposition. Where such irregularities are detected, followup volumetric examinations are performed.” Based on the wording “surface irregularities indicative of significant loss of material,” it is not clear to the staff that surface irregularities indicative of wall loss below nominal would be documented in the corrective action program. It is also not clear to the staff that volumetric wall thickness measurements would be conducted when visual inspection results reveal surface irregularities that could be indicative of wall loss below nominal pipe wall thickness. Request:

1. State whether surface irregularities indicative of wall loss below nominal would be documented in the corrective action program.

2. State whether volumetric wall thickness measurements would be conducted when visual

inspection results reveal surface irregularities that could be indicative of wall loss below nominal pipe wall thickness.

3. If not, state the basis for the portion(s) of the response that represent an exception to

LR-ISG-2012-02 AMP XI.M27.


Exelon Response:

1. The nominal pipe wall thickness is tabulated for various pipe sizes and schedules in ASME B36.10M, Welded and Seamless Wrought Steel Pipe. The wall thickness values listed in this ASME standard are the design wall thicknesses for new piping from the pipe manufacturer. However, variations in the wall thickness are permissible due to mill tolerances in the manufacturing process (generally 12.5%). As such, acceptable new piping from the manufacturer could have a wall thickness as much as 12.5% below the nominal wall thickness prior to the occurrence of any age-related degradation. Since the nominal wall thickness is the design wall thickness of new piping, any indications of loss of material, no matter how trivial, would be an indication of wall loss below nominal. The piping managed by the Fire Water System (B.2.1.16) aging management program will have been exposed to a raw water environment for approximately 40 years before the program is implemented. Uniform corrosion of steel piping in a raw water environment is expected to occur and, as such, the wall thickness of all Fire Protection System piping can be expected to be below the nominal wall thickness. However, due to the low pressure of the system, the pressure boundary function of Fire Protection System piping is maintained at wall thicknesses well below nominal. The results of visual inspections that indicate the condition of the Fire Protection System piping is as-expected (i.e., the surface is subject to uniform general corrosion with no noticeable deposits of corrosion products in excess of a normal oxide layer) will be acceptable. Internal visual inspections are incapable of providing a quantitative assessment of the amount of wall loss of system components and instead provide only a qualitative assessment of the internal condition of the system. Since internal visual inspections are inherently qualitative, the use of quantitative acceptance criteria (e.g., wall loss beyond 12.5% of nominal wall thickness is unacceptable) is not practical. As such, visual inspection results will be entered into the corrective action program if unexpected levels of degradation are identified. Unexpected levels of degradation include excessive accumulation of corrosion products and appreciable localized corrosion (e.g., pitting) beyond a normal oxide layer. Therefore, all surface irregularities that could be indicative of wall loss below nominal pipe wall thickness identified during internal visual inspections of the Fire Protection System will not be documented in the corrective action program.

2. As discussed above, uniform general corrosion of the Fire Protection System piping is

expected due to the service environment. Therefore, the wall thickness of the Fire Protection System piping is expected to be below nominal due to the amount of time the system has been in service. General corrosion of the system is expected to be relatively uniform throughout the system. Since, as described above, internal visual inspections are inherently qualitative and are incapable of providing a quantitative assessment of the amount of wall loss of system components, the Fire Water System (B.2.1.16) aging management program provides for periodic volumetric wall thickness measurements of system piping to monitor the condition of system piping. The program relies on guided wave inspections as a screening tool to identify locations for follow-up ultrasonic testing. In addition, the program provides for internal visual inspections or radiographic testing (RT) of system piping for internal flow blockage. In addition to detecting flow blockage, the internal visual inspections provide qualitative information on the condition and level of degradation of the internal surface of Fire Protection System piping. If unexpected degradation is identified during internal visual inspections, the condition will be entered into the corrective action program and appropriate corrective actions will be performed.


Corrective actions may include follow-up volumetric inspections, if appropriate. Therefore, volumetric wall thickness measurements will not necessarily be conducted when visual inspection results reveal surface irregularities that could be indicative of wall loss below nominal pipe wall thickness.

3. GALL Report, Revision 2, AMP XI.M27, “Fire Water System,” recommended the

performance of periodic wall thickness measurements using non-intrusive techniques to manage loss of material of Fire Protection System piping. LR-ISG-2012-02 revised AMP XI.M27 to recommend that periodic non-intrusive wall thickness measurements no longer be used in lieu of internal visual inspections since wall thickness measurements alone are incapable of detecting internal flow blockage in system piping. However, since internal visual inspections alone are incapable of accurately determining the extent of loss of material, the revised program in LR-ISG-2012-02 recommends follow-up volumetric inspections whenever surface irregularities indicative of wall loss below nominal are identified during internal visual inspections that are performed to detect loss of material.

The BBS Fire Water System (B.2.1.16) aging management program utilizes the best practices from GALL Report, Revision 2, AMP XI.M27 and the subsequent revision to AMP XI.M27 provided in LR-ISG-2012-02. The BBS Fire Water System (B.2.1.16) aging management program provides for periodic volumetric examinations to monitor for loss of material in system piping as well as internal visual inspections or RT to monitor for flow blockage. Follow-up volumetric inspections will be performed as determined by the 10 CFR Part 50 Appendix B corrective action program when visual inspections identify unexpected levels of degradation. This approach is consistent with the intent of the NRC’s guidance on aging management of Fire Protection System piping in that both volumetric inspections (for loss of material) and internal visual inspection or RT (for flow blockage) are performed. It is well established that periodic wall thickness measurements of representative segments of Fire Protection System piping is an effective means of managing age-related loss of material. The volumetric inspections provided for by the Fire Water System (B.2.1.16) aging management program are not performed in lieu of inspections for flow blockage. In addition to the volumetric inspections, periodic internal visual inspections or RT will be performed to monitor for flow blockage. Internal visual inspections will only provide qualitative information on the condition and level of degradation of the internal surface of Fire Protection System piping. Since acceptable new piping can have a wall thickness as much as 12.5% below the nominal wall thickness and since the Fire Protection System operates at low pressure, identification of surface irregularities indicative of wall loss below nominal during internal visual inspections is an overly restrictive threshold for requiring entry of the condition into the corrective action program and follow-up volumetric inspections. Instead the program requires that if unexpected levels of degradation are identified during internal visual inspections, then the condition is entered into the corrective action program. The program relies on the 10 CFR Part 50 Appendix B corrective action program to determine if follow-up volumetric inspections are warranted. In conclusion, there is reasonable assurance that the BBS Fire Water System (B.2.1.16) aging management program will ensure that aging is adequately managed such that


intended functions are maintained consistent with the current licensing basis through the period of extended operation based on the following:

1. The BBS program incorporates the best practices from GALL Report, Revision 2,

AMP XI.M27 and the subsequent revision to AMP XI.M27 provided in LR-ISG-2012-02 with respect to detection of loss of material and flow blockage (i.e., internal visual inspection or RT will be performed to detect flow blockage and volumetric inspections will be performed to detect loss of material).

2. Volumetric inspections for loss of material will not be performed in lieu of inspections for flow blockage but rather in addition to these inspections.

3. Internal visual inspections will provide qualitative information on the condition and level of degradation of the internal surface of Fire Protection System piping and degraded conditions beyond the expected level of degradation will be entered into the corrective action program for evaluation.

4. Due to the low pressure of the Fire Protection System, the pressure boundary function of system piping is maintained at wall thicknesses significantly below nominal.

LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B to clarify that internal visual inspections of Fire Protection System piping are primarily for detection of flow blockage and provide only qualitative assessment of loss of material.


RAI 3.5.2.10-1 Applicability: Byron and Braidwood Background: Title 10 of the Code of Federal Regulations (10 CFR) Part 54.21 (a)(3) states that for structures and components (SCs) subject to an aging management review (AMR) it shall be demonstrated that the effects of aging will be adequately managed so that the intended function(s) will be maintained consistent with the current licensing basis for the period of extended operation. LRA Table 3.5.2-10, “Main Steam & Auxiliary Feedwater Tunnels and Isolation Valve Rooms Summary of Aging Management Evaluation,” states that polymer blowout panels exposed to air- indoor (uncontrolled) or air-outdoor will be managed for change in material properties by the Structures Monitoring Program. The AMR items cite generic note J, which states that neither the component nor the material and environment combination is evaluated in NUREG-1801, “Generic Aging Lessons Learned (GALL) Report,” Revision 2. The AMR items also cite plant specific note 1, which states that the blowout panels are constructed of extruded polystyrene. Issue: Although the scope of the Structures Monitoring Program has been enhanced to include inspection of blowout panels, the parameters monitored or inspected and acceptance criteria for this material have not been specified in the program elements. Unlike GALL Report aging management programs (AMPs) XI.M36, “External Surfaces Monitoring of Mechanical Components,” and XI.M38, “Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components,” GALL Report AMP XI.S6, “Structures Monitoring Program,” does not include examples of inspection parameters for polymeric components. Based on the staff’s review of this material exposed to an air-indoor and air-outdoor environment, the staff noted that at high temperatures, this material may begin to degrade. The staff does not have sufficient information to conclude that the visual inspections performed under the Structures Monitoring Program would identify a change in material properties, prior to a loss of intended function. Request: State how the visual inspections performed under the Structures Monitoring Program would identify a change in material properties for these components, and provide the acceptance criteria by which they would be evaluated. Exelon Response: Visual inspections performed under the Structures Monitoring (B.2.1.34) aging management program will identify a change in material properties of polymeric (i.e., polystyrene) blowout panels through observations of discoloration, cracking, crazing, and loss of material. These visual indicators for changes in material properties of polymeric materials are consistent with examples of parameters described in GALL Report AMPs XI.M36, “External Surfaces Monitoring of Mechanical Components,” and XI.M38, “Inspection of Internal Surfaces of Miscellaneous Piping and Ducting Components” for inspections of rigid mechanical polymeric


materials. The polystyrene blowout panels are not flexible, therefore physical manipulation of the material is not required to augment visual inspection to determine a change in material properties. Acceptance criteria for inspection of polymeric structural components will consist of no observations of discoloration, cracking, crazing, or loss of material indicative of a change in material properties that could result in a loss of component intended function (e.g., pressure relief, shelter and protection). In order to ensure proper aging management of polymeric materials, the Structures Monitoring (B.2.1.34) aging management program will be enhanced to address the inspection and inspection parameters of polymeric materials. LRA Appendix A, Section A.2.1.34, and Appendix B, Section B.2.1.34, are revised as shown in Enclosure B of this letter to include the new enhancement. The Byron and Braidwood LRA Table A.5 Commitment List, Item 34, is also revised as shown in Enclosure C of this letter.

RS-14-169 Enclosure B

Page 1 of 10

Enclosure B

Byron and Braidwood Stations, Units 1 and 2 License Renewal Application (LRA) updates resulting

from the responses to the following RAIs:

RAI B.2.1.16-1a RAI B.2.1.16-1b RAI 3.5.2.10-1

Note: To facilitate understanding, the original LRA pages have been repeated in this Enclosure, with revisions indicated. Existing LRA text and text inserted as a result of the responses to previous RAIs is shown in normal font. Changes are highlighted with bolded italics for inserted text and strikethroughs for deleted text. In addition, Exelon Letter RS-14-078, dated March 13, 2014, inadvertently omitted text that had previously been inserted into LRA Sections A.2.1.16 and B.2.1.16 as part of the response to RAI 3.0.3-2 (Exelon Letter RS-14-003, dated January 13, 2014). This enclosure corrects this discrepancy. Text inserted into LRA Sections A.2.1.16 and B.2.1.16 as a result of the responses to RAI B.2.1.16-1a and RAI B.2.1.16-1b is highlighted by bolded italics. Text deleted as a result of the response to RAI B.2.1.16-1a is highlighted by strikethroughs. Existing text from the LRA and text inserted as a result of the responses to RAI 3.0.3-2 (Exelon Letter RS-14-003, dated January 13, 2014), RAI B.2.1.16-1 (Exelon Letter RS-14-078, dated March 13, 2014), and RAI B.2.1.16-2 (Exelon Letter RS-14-078, dated March 13, 2014) is shown in normal font.


Page 2 of 10 As a result of the responses to RAI B.2.1.16-1a and RAI B.2.1.16-1b provided in Enclosure A of this letter, LRA Appendix A, Section A.2.1.16 is revised as shown below. Text inserted as a result of the responses to RAI B.2.1.16-1a and RAI B.2.1.16-1b is highlighted by bolded italics. Text deleted as a result of the response to RAI B.2.1.16-1a is highlighted by strikethroughs. Existing text from the LRA and text inserted as a result of the responses to RAI 3.0.3-2 (Exelon Letter RS-14-003, dated January 13, 2014), RAI B.2.1.16-1 (Exelon Letter RS-14-078, dated March 13, 2014), and RAI B.2.1.16-2 (Exelon Letter RS-14-078, dated March 13, 2014) is shown in normal font.

A.2.1.16 Fire Water System The Fire Water System aging management program is an existing condition monitoring program that provides for system pressure monitoring, system header flushing, buried ring header flow testing, pump performance testing, hydrant full flow flushing and full flow verification, sprinkler and deluge system flushing and flow testing, hydrostatic testing, and inspection activities. Major component types managed by this program include sprinklers, fittings, valves, hydrants, hose stations, standpipes, tanks, pumps, and aboveground and buried piping and components. There are no underground (i.e., below grade but contained within a tunnel or vault) piping and components within the scope of the Fire Water System aging management program. This program manages aging effects of loss of material due to corrosion (including MIC), reduction in heat transfer due to fouling, and flow blockage due to fouling. Opportunistic visual inspections, performed when the internal surface of the system is made accessible due to normal plant maintenance activities, and existing volumetric non-destructive examinations (i.e., guided wave and ultrasonic inspections) will be credited to ensure age related degradation is identified prior to loss of system intended function. At Byron only, the program will be enhanced to require a minimum of 30 volumetric examinations during each three year interval. In addition, the program will be enhanced to perform additional inspections as described in the Enhancements below. Internal visual inspections are primarily relied upon for detection of flow blockage. Internal visual inspections are only capable of providing qualitative assessments of the internal condition of system piping with respect to loss of material. If unexpected levels of degradation are identified then the condition is entered into the corrective action program for evaluation. Unexpected levels of degradation include excessive accumulation of corrosion products and appreciable localized corrosion (e.g., pitting) beyond a normal oxide layer. Buried ring header flow tests measure hydraulic resistance and compare results with previous testing as a means of evaluating the internal piping conditions. Monitoring system piping flow characteristics ensures that signs of loss of material will be detected in a timely manner. System functional tests, flow tests (including air flow tests), flushes, and inspections are performed in accordance with the applicable guidance from National Fire Protection Association (NFPA) codes and standards. The program will be enhanced to include annual main drain testing in accordance with NFPA 25, Section 13.2.5. These activities are performed periodically to ensure that the loss of material due to corrosion aging effect is managed such that the system and component intended functions are maintained.


Page 3 of 10

In addition, the program will be enhanced to require portions of the water-based fire protection system that are: (a) normally dry but periodically subjected to flow and (b) cannot be drained or allow water to collect be subjected to augmented testing beyond that specified in NFPA 25. The augmented testing will include: (1) periodic full flow tests at the design pressure and flow rate or internal visual inspections and (2) volumetric wall-thickness examinations. Inspections and testing will commence five (5) years prior to the period of extended operation and will be conducted on a five (5) year frequency thereafter. In addition, the internal coatings of components within the scope of this program are periodically visually inspected to ensure that loss of coating integrity is detected prior to (1) loss of component intended function, including loss of function due to accelerated degradation caused by localized coating failures, and (2) degradation of downstream component performance due to flow blockage. The Fire Water System aging management program will be enhanced to:

1. Replace sprinkler heads or perform 50-year sprinkler head testing using the guidance of NFPA 25 “Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems” (2002 Edition), Section 5.3.1.1.1. This testing will be performed at the 50- year in-service date and every 10 years thereafter.

2. Provide for chemical addition, accompanied with system flushing to allow for adequate dispersal of the chemicals throughout the system, to prevent or minimize microbiologically induced corrosion (Byron only) 3. Perform main drain testing annually, in accordance with NFPA 25, “Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems,” Section 13.2.5. 4. Perform air flow testing of deluge systems that are not subject to periodic full flow testing on a three (3) year frequency to verify that internal flow blockage is not occurring (Byron only). 5. Perform inspections of Fire Protection System strainers when the system is reset after automatic actuation for signs of internal flow blockage (e.g., buildup of corrosion particles) (Braidwood only). 6. Increase the frequency of visual inspections of the internal surface of the foam concentrate tanks to at least once every ten (10) years. 7. Perform non-destructive examinations capable of detecting internal flow blockage (e.g., digital radiography) radiographic testing or internal visual inspections every five (5) years at the end of one (1) fire main and the end of one (1) sprinkler system branch line in each structure containing in-scope water-based fire suppression systems in half of the wet pipe sprinkler system within the scope of license renewal. If internal flow blockage that could result in failure of the system to deliver the required flow is identified, then perform an obstruction investigation.


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8. Perform augmented testing beyond that specified in NFPA 25 on those portions of the water-based fire protection system that are: (a) normally dry but periodically subjected to flow and (b) cannot be drained or allow water to collect. The augmented testing will include: (1) periodic full flow tests at the design pressure and flow rate or internal visual inspections and (2) volumetric wall-thickness examinations. Inspections and testing will commence five (5) years prior to the period of extended operation and will be conducted on a five (5) year frequency thereafter. 9. Perform a minimum of 30 volumetric examinations of Fire Protection System piping during each three year interval (Byron only).

These enhancements will be implemented prior to the period of extended operation, with the testing and inspections performed in accordance with the schedule described above.


Page 5 of 10 As a result of the responses to RAI B.2.1.16-1a and RAI B.2.1.16-1b provided in Enclosure A of this letter, LRA Appendix B, Section B.2.1.16 is revised as shown below. Text inserted as a result of the responses to RAI B.2.1.16-1a and RAI B.2.1.16-1b is highlighted by bolded italics. Text deleted as a result of the response to RAI B.2.1.16-1a is highlighted by strikethroughs. Existing text from the LRA and text inserted as a result of the responses to RAI 3.0.3-2 (Exelon Letter RS-14-003, dated January 13, 2014), RAI B.2.1.16-1 (Exelon Letter RS-14-078, dated March 13, 2014), and RAI B.2.1.16-2 (Exelon Letter RS-14-078, dated March 13, 2014) is shown in normal font.

B.2.1.16 Fire Water System

Program Description

The Fire Water System aging management program is an existing condition monitoring program that manages the loss of material aging effect for the water-based fire protection system and associated components, through the use of system pressure monitoring, system header flushing, buried ring header flow testing, pump performance testing, hydrant full flow flushing and full flow verification, sprinkler and deluge system flushing and flow testing, hydrostatic testing, and inspection activities. This program manages aging effects of loss of material due to corrosion (including MIC), reduction in heat transfer due to fouling, and flow blockage due to fouling. In addition, the Fire Water System aging management program manages the loss of coating integrity aging effect for the components with internal coatings within the scope of the program.

The program applies to water-based fire protection systems that consist of sprinklers, fittings, valves, hydrants, hose stations, standpipes, tanks, pumps, and aboveground and buried piping and components. The program manages aging of fire protection components exposed to outdoor air and raw water. There are no underground (i.e., below grade but contained within a tunnel or vault) piping and components within the scope of the Fire Water System aging management program at Byron and Braidwood Stations. Aging of the external surfaces of buried fire main piping is managed as described in the Buried and Underground Piping (B.2.1.28) aging management program.

The fire water system is maintained at the required normal operating pressure and monitored such that a loss of system pressure is immediately detected and corrective actions initiated. The program ensures that testing and inspection activities are performed and the results are documented and reviewed by the Fire Protection system manager for analysis and trending. These monitoring methods are effective in detecting the applicable aging effects and the frequency of monitoring is adequate to prevent significant age-related degradation.

Opportunistic visual inspections, performed when the internal surface is made accessible due to normal plant maintenance activities, and existing volumetric non-destructive examinations (i.e., guided wave and ultrasonic inspection) of piping will be credited to ensure age related degradation is identified prior to loss of system intended function. Selected portions of the fire protection system piping located aboveground and exposed to water will be inspected by non-intrusive volumetric examinations, to ensure that aging effects are managed and that pipe wall thickness is within acceptable limits. Pipe wall thickness inspections will be performed before the


Page 6 of 10

end of the current operating term and continued at a frequency of at least once every 3 years during the period of extended operation. At Byron only, as a result of operating experience, the program will be enhanced to require a minimum of 30 volumetric examinations during each three year interval. These inspections will be capable of evaluating pipe wall thickness to ensure against loss of system intended function. Wall thickness evaluations will not be used in lieu of conducting flow tests or inspections for flow blockage. The program will be enhanced to perform additional inspections as described in the Enhancements below. Internal visual inspections or radiographic testing will be performed at the end of one (1) fire main and the end of one (1) branch line on half of the wet pipe sprinkler system every five (5) years. The wet pipe sprinkler systems that are not inspected during a five (5) year period will be inspected during the subsequent five (5) year period. Internal visual inspections are primarily relied upon for detection of flow blockage. Internal visual inspections are only capable of providing qualitative assessments of the internal condition of system piping with respect to loss of material. If unexpected levels of degradation are identified then the condition is entered into the corrective action program for evaluation. Unexpected levels of degradation include excessive accumulation of corrosion products and appreciable localized corrosion (e.g., pitting) beyond a normal oxide layer.

In addition, periodic visual inspections of components with internal coatings are performed. The visual inspections ensure that loss of coating integrity is detected prior to (1) loss of component intended function, including loss of function due to accelerated degradation caused by localized coating failures, and (2) degradation of downstream component performance due to flow blockage.

Buried ring header flow tests measure hydraulic resistance and compare results with previous testing as a means of evaluating the internal piping conditions. Monitoring system piping flow characteristics ensures that signs of loss of material will be detected in a timely manner.

50-year sprinkler head testing will be conducted using the guidance provided in NFPA 25. Performance of the initial 50-year tests will be determined based on the date of the sprinkler system installation. Subsequent inspections will be performed every 10 years after the initial 50-year testing.

At Byron only, as a result of operating experience, an enhancement to allow for chemical addition, accompanied with system flushing to allow for adequate dispersal of the chemicals throughout the system, to prevent or minimize microbiologically induced corrosion has been included in the Fire Water System aging management program. In addition, the program is enhanced to require a minimum of 30 volumetric examinations during each three year interval to address Byron operating experience.

System functional tests, flow tests (including air flow tests), flushes, and inspections are performed in accordance with the applicable guidance from National Fire Protection Association (NFPA) codes and standards. The program will be enhanced to include annual main drain testing in accordance with NFPA 25, Section 13.2.5. These activities are performed periodically to ensure that the loss of material due to corrosion aging effect is managed such that the system and component intended functions are maintained.


Page 7 of 10

For portions of the water-based fire protection system that are: (a) normally dry but periodically subjected to flow and (b) cannot be drained or allow water to collect the Fire Water System (B.2.1.16) aging management program will be enhanced to require augmented testing beyond that specified in NFPA 25. Augmented testing of these portions of the water-based fire protection system will be performed as follows:

a. Full flow testing at the design pressure and flow rate or internal visual inspections

of the internal surface of portions of the system that meet the above criteria will be periodically performed to ensure flow blockage is not occurring. In addition, volumetric examinations will be performed to verify that significant loss of material is not occurring.

b. Flow testing and visual inspections will be capable of detecting flow blockage. Volumetric examinations will measure wall thickness and detect age-related loss of material.

c. Inspections and testing will commence five (5) years prior to the period of extended operation and will be conducted on a five (5) year frequency thereafter.

d. Flow testing and visual inspections will monitor for flow blockage in 100% of the applicable portions of the water-based fire protection system. Volumetric examinations will be performed on 20% of the applicable portions of the water-based fire protection system. The 20% of piping that is inspected in each five year interval will be in different locations than previously inspected.

e. Reduction in flow such that the system is not capable of performing its intended function will be entered into the corrective action program. Wall thickness measurements below nominal wall thickness will be entered into the corrective action program.

NUREG-1801 Consistency

The Fire Water System aging management program will be consistent with the ten elements of aging management program XI.M27, “Fire Water System,” specified in NUREG-1801.

Exceptions to NUREG-1801

None.

Enhancements

Prior to the period of extended operation, the following enhancements will be implemented in the following program elements:

1. Replace sprinkler heads or perform 50-year sprinkler head testing using the guidance of NFPA 25 “Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems” (2002 Edition), Section 5.3.1.1.1. This testing will be performed at the 50- year in-service date and every 10 years thereafter. Program Elements Effected: Parameters Monitored/Inspected (Element 3), Detection of Aging Effects (Element 4)

2. Provide for chemical addition, accompanied with system flushing to allow for adequate dispersal of the chemicals throughout the system, to prevent or minimize


Page 8 of 10

microbiologically induced corrosion (Byron only). Program Elements Effected: Preventive Actions (Element 2)

3. Perform main drain testing annually, in accordance with NFPA 25, “Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems,” Section 13.2.5. Program Elements Effected: Parameters Monitored/Inspected (Element 3), Detection of Aging Effects (Element 4)

4. Perform air flow testing of deluge systems that are not subject to periodic full flow testing on a three (3) year frequency to verify that internal flow blockage is not occurring (Byron only). Program Elements Effected: Parameters Monitored/Inspected (Element 3), Detection of Aging Effects (Element 4)

5. Perform inspections of Fire Protection System strainers when the system is reset after automatic actuation for signs of internal flow blockage (e.g., buildup of corrosion particles) (Braidwood only). Program Elements Effected: Detection of Aging Effects (Element 4)

6. Increase the frequency of visual inspections of the internal surface of the foam concentrate tanks to at least once every ten (10) years. Program Elements Effected: Detection of Aging Effects (Element 4)

7. Perform non-destructive examinations capable of detecting internal flow blockage (e.g., digital radiography) radiographic testing or internal visual inspections every five (5) years at the end of one (1) fire main and the end of one (1) sprinkler system branch line in each structure containing in-scope water-based fire suppression systems in half of the wet pipe sprinkler system within the scope of license renewal. If internal flow blockage that could result in failure of the system to deliver the required flow is identified, then perform an obstruction investigation. Program Elements Effected: Detection of Aging Effects (Element 4)

8. Perform augmented testing beyond that specified in NFPA 25 on those portions of the water-based fire protection system that are: (a) normally dry but periodically subjected to flow and (b) cannot be drained or allow water to collect. The augmented testing will include: (1) periodic full flow tests at the design pressure and flow rate or internal visual inspections and (2) volumetric wall-thickness examinations. Inspections and testing will commence five (5) years prior to the period of extended operation and will be conducted on a five (5) year frequency thereafter. Program Elements Effected: Scope of Program (Element 1), Detection of Aging Effects (Element 4)

9. Perform a minimum of 30 volumetric examinations of Fire Protection System piping during each three year interval (Byron only). Program Elements Effected: Parameters Monitored/Inspected (Element 3), Detection of Aging Effects (Element 4)


Page 9 of 10 As a result of the response to RAI 3.5.2.10-1 provided in Enclosure A of this letter, LRA Appendix A, Section A.2.1.34, page A-38, is revised to add Enhancement 17 as shown below. Text inserted as a result of the response to RAI 3.5.2.10-1 is highlighted by bolded italics. Existing text from the LRA is shown in normal font. A.2.1.34 Structures Monitoring The Structures Monitoring aging management program will be enhanced to:

17. Perform visual inspections of polymeric components, such as blowout panels, for changes in material properties. Observations of material discoloration, cracking, crazing, and loss of material will provide visual indications of changes in material properties prior to a loss of component intended function.

These enhancements will be implemented prior to the period of extended operation.


Page 10 of 10

As a result of the response to RAI 3.5.2.10-1 provided in Enclosure A of this letter, LRA Appendix B, Section B.2.1.34, page B-225, is revised to add Enhancement 17 as shown below. Text inserted as a result of the response to RAI 3.5.2.10-1 is highlighted by bolded italics. Existing text from the LRA is shown in normal font. B.2.1.34 Structures Monitoring Enhancements


17. Perform visual inspections of polymeric components, such as blowout panels, for

changes in material properties. Observations of material discoloration, cracking, crazing, and loss of material will provide visual indications of changes in material properties prior to a loss of component intended function. Program Elements Affected: Parameters Monitored or Inspected (Element 3), Detection of Aging Effects (Element 4), Acceptance Criteria (Element 6)

RS-14-169 Enclosure C Page 1 of 4

Enclosure C

Byron and Braidwood Stations (BBS) Units 1 and 2

License Renewal Commitment List Changes This Enclosure identifies commitments made or revised 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 the Exelon response to the following RAIs:

RAI B.2.1.16-1a RAI 3.5.2.10-1

In addition, an editorial discrepancy related to the title of the aging management program referenced in LRA Appendix A, Table A.5, Item 16 is corrected. Notes:

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

Existing text from the LRA and text inserted as a result of the responses to previous RAIs is shown in normal font. Changes are highlighted with bolded italics for inserted text and strikethroughs for deleted text.


As a result of the response to RAI B.2.1.16-1a provided in Enclosure A of this letter, LRA Appendix A, Table A.5 License Renewal Commitment List, Item 16 on page A-76, is revised to modify Enhancement 7 as shown below. In addition, an editorial discrepancy related to the title of the program is corrected as shown below. Text inserted as a result of the response to RAI B.2.1.16-1a and the correction of the editorial discrepancy is highlighted by bolded italics. Text deleted as a result of the response to RAI B.2.1.16-1a is highlighted by strikethroughs. Existing text from the LRA and text inserted as a result of the responses to RAI B.2.1.16-1 (Exelon Letter RS-14-078, dated March 13, 2014) and RAI B.2.1.16-2 (Exelon Letter RS-14-078, dated March 13, 2014) is shown in normal font.

A.5 LICENSE RENEWAL COMMITMENT LIST

NO. PROGRAM OR

TOPIC COMMITMENT

IMPLEMENTATION SCHEDULE

SOURCE

16 Fire Water System Fire Water System is an existing program that will be enhanced to: 1. Replace sprinkler heads or perform 50-year sprinkler head testing

using the guidance of NFPA 25 “Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems” (2002 Edition), Section 5.3.1.1.1. This testing will be performed at the 50-year in-service date and every 10 years thereafter.

2. Provide for chemical addition accompanied with system flushing to allow for adequate dispersal of the chemicals throughout the system, to prevent or minimize microbiologically induced corrosion (Byron only) Note 3.

3. Perform main drain testing annually, in accordance with NFPA 25,

“Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems,” Section 13.2.5.

4. Perform air flow testing of deluge systems that are not subject to

periodic full flow testing on a three (3) year frequency to verify that internal flow blockage is not occurring (Byron only)Note 1.

5. Perform inspections of Fire Protection System strainers when the

system is reset after automatic actuation for signs of internal flow blockage (e.g., buildup of corrosion particles) (Braidwood only)Note 1.

6. Increase the frequency of visual inspections of the internal surface

of the foam concentrate tanks to at least once every ten (10) years.

Program to be enhanced prior to the period of extended operation. Inspection schedule identified in commitment.

Section A.2.1.16 Exelon letter RS-14-078 03/13/2014 RAI B.2.1.16-1 RAI B.2.1.16-2 Exelon letter RS-14-169 06/16/2014 RAI B.2.1.16-1a


NO. PROGRAM OR

TOPIC COMMITMENT


SOURCE

7. Perform non-destructive examinations capable of detecting

internal flow blockage (e.g., digital radiography) radiographic testing or internal visual inspections every five (5) years at the end of one (1) fire main and the end of one (1) sprinkler system branch line in each structure containing in-scope water-based fire suppression systems in half of the wet pipe sprinkler system within the scope of license renewal. If internal flow blockage that could result in failure of the system to deliver the required flow is identified, then perform an obstruction investigation.

8. Perform augmented testing beyond that specified in NFPA 25 on

those portions of the water-based fire protection system that are: (a) normally dry but periodically subjected to flow and (b) cannot be drained or allow water to collect. The augmented testing will include: (1) periodic full flow tests at the design pressure and flow rate or internal visual inspections and (2) volumetric wall-thickness examinations. Inspections and testing will commence five (5) years prior to the period of extended operation and will be conducted on a five (5) year frequency thereafter.

9. Perform a minimum of 30 volumetric examinations of Fire

Protection System piping during each three year interval (Byron only)Note 3.


As a result of the response to RAI 3.5.2.10-1 provided in Enclosure A of this letter, LRA Appendix A, Table A.5 License Renewal Commitment List, Item 34 on page A-87, is revised to add Enhancement 17 as shown below. Text inserted as a result of the response to RAI 3.5.2.10-1 is highlighted by bolded italics. Existing text from the LRA and text inserted as a result of the responses to RAI 2.1-3 (Exelon Letter RS-13-274, dated December 19, 2013) and RAI B.2.1.34-1 (Exelon Letter RS-14-097, dated April 17, 2014) is shown in normal font.

A.5 LICENSE RENEWAL COMMITMENT LIST

NO. PROGRAM OR

TOPIC COMMITMENT


SOURCE

34 Structures Monitoring Structures Monitoring is an existing program that will be enhanced to:

17. Perform visual inspections of polymeric components, such as blowout panels, for changes in material properties. Observations of material discoloration, cracking, crazing, and loss of material will provide visual indications of changes in material properties prior to a loss of component intended function.

Program to be enhanced prior to the period of extended operation. .

Section A.2.1.34 Exelon letter RS-13-274 12/19/2013 RAI 2.1-3 Exelon letter RS-14-097 04/17/2014 RAI B.2.1.34-1 Exelon letter RS-14-169 06/16/2014 RAI 3.5.2.10-1

RS-14-169 Enclosure D Page 1 of 9

Enclosure D – Current Revision of LRA Sections

Exelon letter RS-14-078, dated March 13, 2014, inadvertently omitted text that had previously been inserted into LRA Sections A.2.1.16 and B.2.1.16 as part of the response to RAI 3.0.3-2 (Exelon letter RS-14-003, dated January 13, 2014). As a result, Exelon has performed a review of correspondence submitted to the NRC as part of the Byron and Braidwood license renewal project. Based on this review it has been determined that similar issues have occurred related to the Plant Specific Notes following Table 3.1.2-4, Steam Generators – Summary of Aging Management Evaluation and the Fatigue Monitoring (B.3.1.1) aging management program.

Exelon letter RS-14-130, dated May 12, 2014 inadvertently omitted the revision to Table 3.1.2-4, Steam Generators – Summary of Aging Management Evaluation, Plant Specific Note 4, that had previously been made in Exelon letter RS-14-051, dated February 27, 2014.

Exelon letter RS-14-150, dated May 23, 2014 (RAI 4.3.9-1, RAI 4.6.5-1, RAI 4.6.6-1) inadvertently omitted text in LRA Sections A.3.1.1 and B.3.1.1 that had previously been added in Exelon letter RS-14-002, dated January 13, 2014 (RAI B.3.1.1-2).

This enclosure contains the current revision of the Plant Specific Notes following LRA Table 3.1.2-4, including all modifications made to the Plant Specific Notes in previously submitted RAI responses. In addition, this enclosure contains the current revision of LRA Sections A.3.1.1 and B.3.1.1, including all modifications made to these sections in previously submitted RAI responses. This information is provided for clarity to show, in one document, the integrated revisions to the affected LRA sections provided in previous RAI responses. This letter contains no revisions to the Table 3.1.2-4 Plant Specific Notes or to LRA Sections A.3.1.1 and B.3.1.1 that have not been previously submitted.


As discussed in the cover letter, the Plant Specific Notes following Table 3.1.2-4, Steam Generators – Summary of Aging Management Evaluation are provided below, including revisions from all previous RAI responses. The entire section is shown in normal font indicating that no additions or deletions to the Plant Specific Notes are being made as part of this submittal.

Table 3.1.2-4, Steam Generators Summary of Aging Management Evaluation

Plant Specific Notes:

1. The TLAA designation in the Aging Management Programs column indicates that cumulative fatigue damage for this component is evaluated in Section 4.3 and Section 4.7.

2. The Flow-Accelerated Corrosion (B.2.1.8) aging management program will be used to manage wall thinning due to mechanisms other than FAC in stainless steel pipe in treated water > 140°F environments.

3. The Steam Generators (B.2.1.10) program inspection activities include periodic visual inspection of the steam generator secondary side internal components and eddy current testing of the steam generator tubes. The steam generator CASS components are non-pressure retaining, do not perform an intended function at low temperatures, and are not subjected to loads that would result in a non-ductile failure at low temperatures. No additional inspection activities are required to manage the loss of fracture toughness due to thermal aging embrittlement.

4. During power operation, the carbon steel components of the Steam Generators, including the shell, nozzles, instrument bosses, and manways, have an external temperature greater than 212 degrees Fahrenheit and are at a greater temperature than the air-indoor (uncontrolled) environment/air with borated water leakage. During refueling outages, the containment ventilation system is placed in service to dehumidify and reduce containment air dew point temperatures. Therefore, wetting due to condensation and moisture accumulation will not occur during power operation or refueling outages, and loss of material (due to general, pitting, and crevice corrosion) does not apply.

5. NUREG-1801 specifies a plant-specific program. The Steam Generators (B.2.1.10) program will be used to verify the effectiveness of the Water Chemistry (B.2.1.2) program to ensure that cracking due to stress corrosion cracking/primary water stress corrosion cracking is not occurring.

6. Not used.

7. NUREG-1801 specifies a plant-specific program. The Steam Generators (B.2.1.10) program will be used to verify the effectiveness of the Water Chemistry (B.2.1.2) program to ensure that cracking due to stress corrosion cracking/primary water stress corrosion cracking is not occurring. This item is only applicable to Unit 1 since a license amendment (Adams Accession Number: ML12262A360), approved by the NRC, redefined the Unit 2 steam generator pressure boundary in which the tube-to-tubesheet welds are no longer included and do not perform a license renewal intended function. Therefore the Unit 2 steam generator tube-to-tubesheet welds are not in scope for license renewal.


8. The aging effect/mechanism of reduction of heat transfer due to fouling in not in NUREG-1801 for this component, material, and environment, however, it is applicable to this combination. The Water Chemistry (B.2.1.2) program and Steam Generators (B.2.1.10) program are used to manage the aging effects for this component, material, and environment combination.

9. The Unit 1 steam generator Class 1 drain line is ¾ inches NPS which is outside the scope of the One-Time Inspection of ASME Code Class 1 Small Bore-Piping aging management program which is limited to piping and systems less than 4 inches NPS and greater than or equal to 1 inch NPS. The aging effect of cracking will be managed by the ASME Section XI Inservice Inspection, IWB, IWC, and IWD (B.2.1.1) program and Water Chemistry (B.2.1.2) program.


As discussed in the cover letter, LRA Appendix A, Section A.3.1.1 is provided below, including revisions from all previous RAI responses. The entire section is shown in normal font indicating that no additions or deletions to Section A.3.1.1 are being made as part of this submittal. A.3.1.1 Fatigue Monitoring

The Fatigue Monitoring aging management program is an existing preventive program that manages cumulative fatigue damage of the reactor pressure vessel (RPV) components, reactor coolant pressure boundary piping components, and other components. The Fatigue Monitoring aging management program manages fatigue of piping, piping elements, piping components, bolting, reactor vessels, reactor vessel internals, supports, heat exchangers and other components.

The Fatigue Monitoring aging management program monitors and tracks critical thermal, pressure, and seismic transients to ensure each analyzed component does not exceed the number of allowable cycles, thus ensuring that the cumulative usage factor (CUF) for each analyzed component does not exceed the design limit of 1.0 through the period of extended operation. The Fatigue Monitoring program also monitors and tracks other design basis events such as LOCAs. The number of allowable cycles is based on the design fatigue analyses transient inputs. The program requires comparison of the actual operational transient parameters to the applicable design transient definitions to assure the actual operational transients are bounded. If an allowable cycle limit is approached or the severity of an actual operational transient is not bounded by the applicable design transient definition, then this condition is entered into and addressed within the corrective action program to ensure that the design CUF limit is not exceeded. The Fatigue Monitoring aging management program will be enhanced to:

1. Address the cumulative fatigue damage effects of the reactor coolant environment on component life by evaluating the impact of the reactor coolant environment on critical components for the plant identified in NUREG/CR-6260. Additional plant-specific component locations in the reactor coolant pressure boundary will be evaluated if they are more limiting than those considered in NUREG/CR-6260.

2. Monitor and track additional plant transients that are significant contributors to component fatigue usage.

3. Evaluate the effects of the reactor coolant system water environment on the reactor vessel internal components with existing fatigue CUF analyses to satisfy the evaluation requirements of ASME Code, Section III, Subsection NG-2160 and NG-3121.

4. Increase the scope of the program to include transients used in the analyses for ASME Section III fatigue exemptions, the allowable stress analyses associated with ASME Section III and ANSI B31.1, and the flaw evaluation analyses performed in accordance with ASME Section XI, IWB-3600.

These enhancements will be implemented prior to the period of extended operation.


As discussed in the cover letter, LRA Appendix B, Section B.3.1.1 is provided below, including revisions from all previous RAI responses. The entire section is shown in normal font indicating that no additions or deletions to Section B.3.1.1 are being made as part of this submittal.

B.3.1.1 Fatigue Monitoring

Program Description The Fatigue Monitoring aging management program is an existing preventive program that manages cumulative fatigue damage of the reactor pressure vessel (RPV) components, reactor coolant pressure boundary (RCPB) piping components, and other components subject to air-indoor uncontrolled, air with borated water, condensation, diesel exhaust, neutron flux, reactor coolant, treated water, treated borated water, and steam. The Fatigue Monitoring aging management program manages cumulative fatigue damage of piping components, piping elements, bolting, reactor vessels, reactor vessel internals, supports, heat exchangers and other components. The program reviews the temperature, pressure, and seismic profiles of the actual operational transients and counts them in the appropriate design transient category.

The Fatigue Monitoring aging management program monitors and tracks critical thermal, pressure, and seismic transients to ensure each analyzed component does not exceed the number of allowable cycles, thus ensuring that the cumulative usage factor (CUF) for each analyzed component does not exceed the design limit of 1.0 through the period of extended operation. The Fatigue Monitoring aging management program also monitors and tracks other design basis events such as LOCAs. The number of allowable cycles is based on the design fatigue analyses transient inputs. The program requires comparison of the actual operational transient parameters to the applicable design transient definitions to assure the actual operational transients are bounded. If an allowable cycle limit is approached or the severity of an actual operational transient is not bounded by the applicable design transient definition, then this condition is entered into and addressed within the corrective action program to ensure that the design CUF limit is not exceeded. The fatigue cycle monitoring data was used to project the numbers of cycles that will occur during 60 years. These projections show that the current 40 year allowable cycle limits will not be exceeded in 60 years. Therefore, the current 40 year cycle limits will be maintained for the period of extended operation. The Fatigue Monitoring aging management program will be enhanced to monitor additional plant transients that are significant contributors to cumulative fatigue damage.

Maintaining the number of cumulative cycles below the analyzed allowable cycle limits assures that the fatigue analyses remains valid. If a cycle limit is approached or the severity of an actual operational transient is not bounded by the applicable design transient definition, the condition is entered into the corrective action program. Fatigue analyses exists for BBS reactor pressure vessels (RPV) components, reactor coolant pressure boundary (RCPB) piping components, and other components (e.g. pumps, heat exchangers, spent fuel pool racks, spent fuel pool liner) in accordance with ASME Section III, Class 1 fatigue design requirements per the current licensing basis. This includes the analyses provided in the original stress reports as well as subsequent analyses developed to evaluate design changes, power rerates, and operational events. These Class 1 fatigue analyses have been identified as Time-Limited Aging


Analyses (TLAAs) that are evaluated in Section 4.0 of the Byron and Braidwood License Renewal Application. In addition, components designed in accordance with ASME Section III, Class 2 and 3 and ANSI B31.1 requirements have been identified as having implicit fatigue Time-Limited Aging Analyses (TLAAs). The program will be enhanced to increase the scope of the program to include transients used in the analyses for ASME Section III fatigue exemptions, the allowable stress analyses associated with ASME Section III and ANSI B31.1, and the flaw evaluation analyses in accordance with ASME Section XI, IWB-3600.

In addition, the program will be enhanced to evaluate the cumulative fatigue damage effect of the reactor coolant environment on reactor pressure vessel (RPV) components and reactor coolant pressure boundary (RCPB) piping components by performing environmentally assisted fatigue analyses for critical locations selected accordance with NUREG/CR-6260 guidance. Additional plant-specific component locations in the reactor coolant pressure boundary will be evaluated if they are more limiting than those considered in NUREG/CR-6260. Environmentally-adjusted cumulative usage factors (CUFen) were computed for each wetted material within the analyzed component or system to assure the limiting case was analyzed. The resulting 60-year CUFen values did not exceed the limit of 1.0. If a CUFen allowable cycle limit is approached, the condition will be entered into and addressed within the corrective action program.

The program will also be enhanced to evaluate the effects of the reactor coolant system water environment on the reactor vessel internal components with existing fatigue CUF analyses to satisfy the evaluation requirements of ASME Code, Section III, Subsection NG-2160 and NG-3121.

NUREG-1801 Consistency

The Fatigue Monitoring aging management program will be consistent with the ten elements of aging management program X.M1, “Fatigue Monitoring,” specified in NUREG-1801.

Exceptions to NUREG-1801

None.

Enhancements


1. Address the cumulative fatigue damage effects of the reactor coolant environment on component life by evaluating the impact of the reactor coolant environment on critical components for the plant identified in NUREG/CR-6260. Additional plant-specific component locations in the reactor coolant pressure boundary will be evaluated if they are more limiting than those considered in NUREG/CR-6260. Program Elements Affected: Scope of Program (Element 1), Preventive Actions (Element 2), Parameters Monitored/Affected (Element 3), Acceptance Criteria (Element 6); Corrective Actions (Element 7)


2. Monitor and track additional plant transients that are significant contributors to

component fatigue usage. Program Elements Affected: Scope of Program (Element 1), Preventive Actions (Element 2), Parameters Monitored/Affected (Element 3), Acceptance Criteria (Element 6), Corrective Actions (Element 7)

3. Evaluate the effects of the reactor coolant system water environment on the reactor vessel internal components with existing fatigue CUF analyses to satisfy the evaluation requirements of ASME Code, Section III, Subsection NG-2160 and NG-3121. Program Elements Affected: Scope of Program (Element 1), Preventive Actions (Element 2), Parameters Monitored/Affected (Element 3), Acceptance Criteria (Element 6), Corrective Actions (Element 7)

4. Increase the scope of the program to include transients used in the analyses for ASME Section III fatigue exemptions, the allowable stress analyses associated with ASME Section III and ANSI B31.1, and the flaw evaluation analyses in accordance with ASME Section XI, IWB-3600. Program Elements Affected: Scope of Program (Element 1), Preventive Actions (Element 2), Parameters Monitored/Affected (Element 3), Acceptance Criteria (Element 6), Corrective Actions (Element 7)

Operating Experience

The following examples of operating experience provide objective evidence that the Fatigue Monitoring program will be effective in ensuring that the intended functions are maintained consistent with the current licensing basis for the period of extended operation: Byron Station

1. In April 2008, during review of Byron Unit 1 plant transient data, engineering observed a large temperature increase of 171°F in approximately one (1) hour in the pressurizer surge line. Since the Byron Technical Specifications and UFSAR chapter 3.9 limit Pressurizer heat-up rate to less than 100 F in an hour, engineering questioned whether the observed temperature increase in pressurizer surge line was applicable to Pressurizer Tech Spec requirements. Research of the Byron design basis showed that pressurizer surge line temperature transients had been analyzed by Westinghouse in 2002. The existing analysis concluded that during plant heatup and cooldown, the pressurizer surge line can undergo temperature changes as observed in the 2008 Byron transient. The analysis concluded that the surge line temperature transients affected only the pressurizer surge line and not the Pressurizer. The effects on the pressurizer surge line were bounded by the surge line stratification study and 2008 observed surge line temperature variations were within the analyzed limits.

This example provides objective evidence that the Fatigue Monitoring aging management program challenges potential discrepancies with respect to transient severity; investigates their potential impact; and utilizes the corrective action program for investigation.


2. In 2012, Byron Unit 2 experienced a loss of offsite power. During this event the

charging system auxiliary pressurizer spray line was valved in to provide pressurizer spray flow in support of the reactor shutdown. During the event, the auxiliary pressurizer spray line water temperature difference exceeded the 320°F differential temperature in the Technical Specifications. This condition was entered into the corrective action program and evaluated in accordance with the Fatigue Monitoring aging management procedure. The transient was evaluated against the pressurizer "Auxiliary Spray Actuation" design transient definition and was confirmed to exceed the 320 °F differential temperature. Therefore, this event was counted as an occurrence against the "Auxiliary Spray Actuation" transient category. The design cycle limit for this transient category is 10 occurrences. Thus, the identified transients with no prior occurrences, was still within the allowable limit of 10 cycles. Review of the Class 1 fatigue analysis showed that the bounding differential temperature of 625 °F is specified as an input to Byron specific fatigue analysis, for a total of 10 cycles. Therefore, the fatigue effects of the 2012 operational transient was analyzed and determined to be bounded by the existing Byron plant design basis.

This example provides objective evidence that the Fatigue Monitoring aging management program effectively monitors plant transients; utilizes the corrective action program; performs evaluations to ensure that actual operational transients are bounded by design transient definitions; and actual occurrence of operational transient cycles are counted against the appropriate cycle transient category.

Braidwood Station

1. In 2006, while performing the Braidwood operational transient cycle counting surveillance, the Fatigue Monitoring program engineer identified some potential design transient definition discrepancies in the site procedure. This condition was entered into the corrective action program. The potential discrepancies had no immediate effect on either of the Braidwood Unit 1 and 2 fatigue monitoring cycle counts. After review of: historical records, technical specifications, the UFSAR, and design basis fatigue analyses procedure changes that clarified design transient definitions and provided additional guidance were recommended. The procedure change recommendations and guidance were approved by corporate and Westinghouse subject experts. The recommendations and guidance were then incorporated into the site Fatigue Monitoring program procedure.

This example provides objective evidence that the Fatigue Monitoring aging management program challenges discrepancies; investigates their potential impact; utilizes the corrective action program; and implements program improvements.

2. In August 2011, the Fatigue Monitoring program engineer reviewed an INPO operating experience (OE) report, that was entered into the corrective action program, that identified another PWR had been operating with a Chemical and Volume Control System (CVCS) letdown flow rate of 120 gpm when their fatigue design basis analysis assumed a normal letdown flow operation at 75 gpm. The OE report stated that the operation of letdown flow rate at 120 gpm resulted in non-conservative design transient assumptions for Class 1 fatigue analysis.


The program engineer recognized that the two Braidwood units also normally operate with the letdown flow rates at the maximum allowable flow rate 120 gpm and not the designed flow rate of 75 gpm. Review of fatigue analysis revealed that letdown operation at 120 gpm is an evaluated transient. The fatigue analysis assumes that the letdown flow is increased to 120 gpm in one step from the normal design value of 75 gpm, and kept at the 120 gpm for 6 hours, and then returned to the design flow of 75 gpm in one step. This event is assumed approximately twice a day or 24,000 times during the 40 year design life of the plant. At Braidwood, the temperature changes due to: the increase in the letdown flow rate from 75 to 120 gpm; the long-term letdown operation at 120 gpm; and the eventual decrease in the letdown flow rate from 120 to 75 gpm would constitute one occurrence in the cycle count. Therefore, the existing fatigue analysis bounded the normal operation of the Chemical and Volume Control System (CVCS) letdown flow at a continuous rate of 120 gpm.

This example provides objective evidence that the Fatigue Monitoring aging management program is proactive in reviewing and evaluating industry operating experience and utilizes the corrective action program for resolution of identified issues.

The above examples provide objective evidence that the existing Fatigue Monitoring aging management program effectively monitors, tracks, and counts operational transients to prevent the aging effect of cumulative fatigue damage. A review of the operating examples showed that inspections have not identified any instances of significant age-related degradation. Problems identified would not cause significant impact to the safe operation of the plant, and adequate corrective actions are taken to prevent recurrence. Appropriate guidance for re-evaluation, repair, or replacement is provided for locations where cumulative fatigue damage may approach established limits. Assessments of the Fatigue Monitoring program aging management are performed to identify the areas that need improvement to maintain the quality performance of the program. Therefore, there is confidence that implementation of the Fatigue Monitoring aging management program will effectively identify age-related degradation prior to failure.

Conclusion

The enhanced Fatigue Monitoring program will provide reasonable assurance that the cumulative fatigue damage aging effect will be adequately managed so that the intended function(s) of components within the scope of license renewal are maintained consistent with the current licensing basis during the period of extended operation.

Documents

Exelon Generation® Exelon Nuclear 200 Exelon Way Fax · Michael P. Gallagher Exelon Generation® Vice President. License Renewal Exelon Nuclear 200 Exelon Way RS-14-169 June 16,