RS-14-078, Response to NRC Requests for Additional Information, Set 7, Dated February 18, 2014 Related to the License Renewal Application

Response to NRC Requests for Additional Information, Set 7, Dated February 18, 2014 Related to the License Renewal Application

ML14073A118
Person / Time
Site:	Byron, Braidwood
Issue date:	03/13/2014
From:	Gallagher M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-14-078
Download: ML14073A118 (34)

Text

10 CFR 50 10 CFR 51 10 CFR 54 RS-14-078 March 13,2014 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:

Response to NRC Requests for Additional Information, Set 7, dated February 18, 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 John W. Daily, US NRC to Michael P. Gallagher, Exelon, dated February 18, 2014, "Requests for Additional Information for the Review of the Byron Nuclear Station, Units 1 and 2, and Braidwood Nuclear Station, Units 1 and 2, License Renewal Application - Aging Management, Set 7 (TAC NOS.

MF1879, MF1880, MF1881, AND MF1882)

In the Reference 1 letter, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2 (BBS). In the Reference 2 letter, the NRC requested additional information to support the staffs' review of the LRA.

March 13,2014 U.S. Nuclear Regulatory Commission Page 2 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.

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. AI Fulvio, Manager, Exelon License Renewal, at 610-765-5936.

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

Executed on Respectfu Ily, tr2erIddfUt,t---....::...--

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 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-14-078 Enclosure A Page 1 of 18 Enclosure A Byron and Braidwood Stations, Units 1 and 2 License Renewal Application Responses to Requests for Additional Information RAI B.2.1.16-1 RAI B.2.1.16-2 RAI 3.1.2.3-1 RAI 3.1.2.3-2

RS-14-078 Enclosure A Page 2 of 18 RAI B.2.1.16-1, Corrosion and flow blockage in fire protection piping Applicability: Byron Nuclear Station, Units 1 and 2 (Byron) and Braidwood Nuclear Station, Units 1 and 2 (Braidwood)

Background:

During its review of plant-specific operating experience, the staff identified instances of potential flow blockage of fire water systems at Byron. Examples include:

• Corrective action reports AR 01088598, AR 01482910 and AR 00798599 document a sprinkler alarm not clearing and finding flow blockage during inspections. These ARs span 2008 to 2013.

• Although addressed by the corrective action program, the operating experience program element of license renewal application (LRA) Section B.2.1.16 states that in March 2008 nine spray nozzles for an auxiliary transformer were discovered plugged during a deluge system flush.

The NRCs recent Information Notice (IN) 2013-06, Corrosion in Fire Protection Piping Due to Air and Water Interaction, identifies blockages in fire sprinkler piping due to accumulation of corrosion products. The associated operating experience has caused the staff to reconsider the current approach in Generic Aging Lessons Learned (GALL) Report aging management program (AMP) XI.M27, Fire Water System, that allows the use of non-intrusive techniques for identifying loss of material to be used in lieu of internal visual inspections or flow tests for identifying blockages. Non-intrusive inspection techniques cannot reliably be used to ensure that the system remains functional because quantities of corrosion products sufficient to block flow could be released into the system despite the remaining pipe wall thickness meeting wall thickness acceptance criteria. In addition, as stated in IN 2013-06, degradation in fire protection systems can be detected before a loss of function by inspecting and testing the systems in accordance with National Fire Protection Association (NFPA) standards. Consequently, the staff considers that the recommendations in AMP XI.M27 should be changed as follows (interim staff guidance is currently being finalized):

• Inspections and tests related to loss of material and flow blockage should meet NFPA recommendations, as listed in the attached Table 1, Fire Water System Inspection and Testing Recommendations.

• For portions of water-based fire protection systems that are designed to be normally dry but are periodically subjected to flow (e.g., dry-pipe or preaction sprinkler system piping and valves), augmented inspections consisting of periodic wall thickness measurements, and either visual examinations or full flow testing should be performed in the portions of this piping that are not configured to completely drain.

LRA Section B.2.1.16, Fire Water System, states that system functional tests, flow tests, flushes, and inspections are performed in accordance with the applicable guidance from NFPA codes and standards and that these activities are performed to ensure that system and component intended functions are maintained. However, the LRA also states that pipe wall thickness inspections are capable of evaluating the inner diameter of the piping as it applies to the flow requirements of the fire protection system.

RS-14-078 Enclosure A Page 3 of 18 Issue:

Based on its reviews during the AMP audit, it is not clear to the staff that the Byron and Braidwood Fire Water System program is consistent with the staff considerations above. In addition, it is not clear how pipe wall thickness inspections are capable of evaluating the inner diameter of the piping as it applies to the flow requirements of the system.

Request:

1. Either confirm that the current Fire Water System program conducts inspections and tests related to loss of material and flow blockage of associated components in accordance with the guidance in Table 1, below, including aspects such as the type of inspection or test, frequency of performance, acceptance criteria, etc., or provide justification to demonstrate that the current activities will adequately manage the effects of aging so that the intended functions will be maintained.

2. If wall thickness evaluations will be used in lieu of conducting flow tests or internal visual examinations, state the bases for why wall thickness measurements in the absence of flow testing or internal visual examinations provide reasonable assurance that the intended functions of in-scope fire water system components will be maintained consistent with the current licensing basis (CLB) for the period of extended operation (PEO). In addition, either provide the technical bases for how pipe wall thickness inspections are capable of evaluating the inner diameter of the piping as it applies to the flow requirements of the fire protection system, or modify that statement in the LRA to reflect technically justifiable bases.

3. Either confirm that follow-up volumetric examinations will be conducted whenever internal visual inspections detect surface irregularities indicative of material loss below nominal wall thickness, or provide the bases for why the visual inspection alone will provide reasonable assurance that the intended functions of in-scope fire water system components will be maintained consistent with the CLB for the PEO. Alternatively, add a requirement to the program to conduct follow-up volumetric examinations.

4. For portions of water-based fire protection system that are designed to be normally dry but are periodically subjected to flow and are not configured to completely drain, state the following:

a. The inspection method to ensure that fouling is not occurring.

b. The parameters to be inspected.

c. When inspections will commence and the frequency of subsequent inspections.

d. The extent of inspections and the basis for the extent of inspections if it is not 100 percent.

e. Acceptance criteria.

f. How much of this piping will be periodically inspected for wall thickness and how often the inspections will occur.

5. If necessary, provide revisions to LRA Section 3 Table 2s, Appendix A, and Appendix B.

Table 1 Fire Water System Inspection and Testing Recommendations1, 2, 5 Description NFPA 25 Section Sprinkler Systems Sprinkler inspections 5.2.1.1 Sprinkler testing 5.3.1 Standpipe and Hose Systems Flow tests 6.3.1

RS-14-078 Enclosure A Page 4 of 18 Table 1 Fire Water System Inspection and Testing Recommendations1, 2, 5 Private Fire Service Mains Underground and Exposed Piping Flow 7.3.1 Tests Hydrants 7.3.2 Fire Pumps Suction screens 8.3.3.7 Valves and System-Wide Testing Main drain test 13.2.5 Deluge valves 13.4.3.2.2 - 13.4.3.2.5 Water Spray Fixed Systems Strainers (refueling outage interval and 10.2.1.6, 10.2.1.7, 10.2.7 after each system actuation)

Operation Test (refueling outage interval) 10.3.4.3 Foam Water Sprinkler Systems Strainers (refueling outage interval and 11.2.7.1 after each system actuation)

Operational Test Discharge Patterns 11.3.2.6 (annually)6 Storage tanks (internal - 10 years) Visual inspection for internal corrosion Obstruction Investigation Obstruction, internal inspection of piping3 14.2 and 14.3 Notes:

1. All terms and references are to the 2011 Edition of NFPA 25. The staff is referencing the 2011 Edition of NFPA 25 for the description of the scope and periodicity of specific inspections and tests. This table specifies those inspections and tests that are related to age-managing applicable aging effects that are associated with loss of material and flow blockage for passive long-lived in-scope components in the fire water system. Inspections and tests not related to the above should be continued to be conducted in accordance with the plants current licensing basis. If the current licensing basis states more frequent inspections than required by NFPA 25 or this table, the plants current licensing basis should be continued to be met.

2. A reference to a section includes all sub-bullets unless otherwise noted (e.g., a reference to 5.2.1.1 includes 5.2.1.1.1 through 5.2.1.1.7).

3. The alternative nondestructive examination methods permitted by 14.2.1.1 and 14.3.2.3 are limited to those that can ensure that flow blockage will not occur.

4. (Not Used)

5. Items in areas that are inaccessible for safety considerations due to factors such as continuous process operations, radiological dose, and energized electrical equipment shall be inspected during each scheduled shutdown but at least once every refueling outage interval.

6. Where the nature of the protected property is such that foam cannot be discharged, the nozzles or open sprinklers shall be inspected for correct orientation and the system tested with air to ensure that the nozzles are not obstructed.

RS-14-078 Enclosure A Page 5 of 18 Exelon Response:

1. The recommendations for inspections and tests related to loss of material and flow blockage of associated components provided in Table 1 of Request 1 above are addressed as follows:

Fire Water System Inspection and Testing NFPA 25 Description Byron and Braidwood Fire Water System AMP Activities Section Sprinkler Systems Sprinkler Visual inspections of sprinkler systems for age-related degradation (e.g., corrosion) or indications 5.2.1.1 inspections of leakage are performed at least annually.

As stated in Enhancement 1 of the Fire Water System (B.2.1.16) aging management program, the sprinkler heads within the scope of license renewal will be replaced or tested after 50 years in Sprinkler testing 5.3.1 service in accordance with Section 5.3.1.1.1 of the 2002 edition of NFPA 25. This is equivalent to the requirements made in Section 5.3.1 of the 2011 edition of NFPA 25 for the sprinklers installed at Byron and Braidwood.

Standpipe and Hose Systems Flow testing at the hydraulically most remote hose connection of each zone of the automatic standpipe system is not performed. However, as described below, the program will be enhanced to perform main drain testing annually, in accordance with Section 13.2.5 of NFPA 25 (see Enhancement 3). The hose stations are supplied by the same headers as the sprinkler and deluge systems. Therefore, the performances of the main drain tests ensure flow blockage in the fire Flow tests 6.3.1 water headers is not occurring. In addition, the Fire Water System (B.2.1.16) aging management program includes flushing and flow verification at each hose station on a frequency of at least once every five (5) years. Flow verification at each hose station in combination with main drain testing provide reasonable assurance that internal flow blockage capable of preventing the system from performing its intended function is not occurring.

Private Fire Service Mains Underground and Flow testing of the underground fire water header at flows representative of those expected during Exposed Piping 7.3.1 a fire is performed on a three (3) year frequency to determine the internal condition of the piping.

Flow Tests Flushing of fire hydrants is performed annually to verify the hydrants are functioning properly and Hydrants 7.3.2 to prevent the build-up of sedimentation in the header.

RS-14-078 Enclosure A Page 6 of 18 Fire Water System Inspection and Testing NFPA 25 Description Byron and Braidwood Fire Water System AMP Activities Section Fire Pumps The suction screens for the intake bays are not in scope for license renewal at BBS. The results of any inspections of the suction screens provide no indication of the condition of the internal surface Suction screens 8.3.3.7 of components within the scope of the Fire Water System (B.2.1.16) aging management program.

Therefore, the inspections of the suction screens described in NFPA 25Section 8.3.3.7 are not applicable.

Valves and System-Wide Testing The Fire Water System (B.2.1.16) aging management program will be enhanced to require the performance of main drain tests annually, in accordance with NFPA 25, Section 13.2.5. As a result Main drain test 13.2.5 of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 3 as shown in Enclosure C.

At Byron, full flow testing of the deluge fire suppression systems for the transformers (i.e., SAT, UAT, MPT) is performed on a frequency of at least once every three (3) years. The Fire Water System (B.2.1.16) aging management program will be enhanced to require air flow testing of all other deluge systems performed on a three (3) year frequency to verify that internal flow blockage is not occurring. As a result of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 4 as shown in Enclosure C.

13.4.3.2.2 -

Deluge valves 13.4.3.2.5 At Braidwood, full flow testing of the deluge fire suppression systems for the transformers (i.e.,

SAT, UAT, MPT) is performed on a frequency of at least once every three (3) years. Air flow testing of all other deluge systems is performed on a three (3) year frequency to verify that internal flow blockage is not occurring.

Surveillance and testing of active functions of system components (e.g., deluge valve cycling and trip testing) will continue in accordance with current licensing basis requirements.

RS-14-078 Enclosure A Page 7 of 18 Fire Water System Inspection and Testing NFPA 25 Description Byron and Braidwood Fire Water System AMP Activities Section Water Spray Fixed Systems Inspections of mainline strainers for the water spray fixed systems are performed as described below. Individual nozzle strainers are not installed at Byron and Braidwood.

The Fire Water System (B.2.1.16) aging management program includes visual inspections of the internal surface of mainline strainers for the water spray fixed systems on a frequency of at least once every six (6) years. Although LR-ISG-2012-02 recommends the inspection of mainline strainers for the water spray fixed systems on a refueling outage frequency, NFPA 25 recommends inspections of mainline strainers on a five (5) year frequency. Since the Fire Protection System is a stagnant system, there is normally no flow through the mainline strainers for the water spray fixed systems and, therefore, buildup of sedimentation or debris on the strainers is unlikely. The mainline strainers for the water spray fixed systems only experience flow during automatic system actuation and periodic flow testing or flushing. In addition, a review of the last ten (10) years of inspection results for Fire Protection System mainline strainers for the water spray fixed systems Strainers (refueling (over 40 total inspections) has identified zero instances of flow blockage. Finally, any potential flow 10.2.1.6, outage interval and blockage of the strainers would be identified during periodic flow testing of the system performed in 10.2.1.7, after each system accordance with NFPA 25 Sections 13.2.5 and 13.4.3.2.2 - 13.4.3.2.5 since the strainers are 10.2.7 actuation) located within the flow path that is tested for obstruction.

Based on the above, periodic inspections of strainers for water spray fixed systems performed on a frequency of at least once every six (6) years is justified. If foreign material capable of causing flow blockage is identified it will be entered into the corrective action program and corrective actions will be taken, including potentially increasing the frequency of inspections, if appropriate.

In addition, at Byron the mainline strainers for the water spray fixed systems are inspected when the system is reset after automatic system actuation. At Braidwood, the Fire Water System (B.2.1.16) aging management program will be enhanced to require strainer inspections when the system is reset after automatic system actuation. As a result of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 5 as shown in Enclosure C.

RS-14-078 Enclosure A Page 8 of 18 Fire Water System Inspection and Testing NFPA 25 Description Byron and Braidwood Fire Water System AMP Activities Section Spray nozzles for water spray fixed systems are visually inspected for obstructions at least once per refueling cycle during periodic surveillance activities (e.g., deluge valve cycling, main drain testing, alarm testing).

In addition, the water discharge patterns for the deluge fire suppression systems for the transformers (i.e., SAT, UAT, MPT) is observed to ensure that patterns are not impeded by plugged nozzles and to ensure that obstructions do not prevent discharge patterns from wetting Operation Test surfaces to be protected during full flow testing performed on a three (3) year frequency. The (refueling outage 10.3.4.3 discharge patterns are observed during periodic full flow testing of the deluge systems. The three interval)

(3) year frequency is consistent with the requirements of NFPA 25, Section 13.4.3.2.2.4.

At Byron, the program will be enhanced to include air flow testing of all other deluge systems to ensure that nozzles are not obstructed, as described above in the Deluge Valves section of this table (see Enhancement 4). At Braidwood, the existing program includes air flow testing of all other deluge systems to ensure that nozzles are not obstructed on a three (3) year frequency. The three (3) year frequency is consistent with the requirements of NFPA 25, Section 13.4.3.2.2.4.

Foam Water Sprinkler Systems Inspections of mainline strainers for the foam fire suppression systems are performed as described below. Individual nozzle strainers are not installed at Byron and Braidwood.

The Fire Water System (B.2.1.16) aging management program includes visual inspections of the internal surface of mainline strainers for the foam fire suppression systems on a frequency of at least once every six (6) years. Although LR-ISG-2012-02 recommends the inspection of mainline Strainers (refueling strainers for the foam fire suppression systems on a refueling outage frequency, NFPA 25 outage interval and 11.2.7.1 recommends inspections of mainline strainers on a five (5) year frequency. Since the Fire after each system Protection System is a stagnant system, there is normally no flow through the mainline strainers for actuation) the foam fire suppression systems and, therefore, buildup of sedimentation or debris on the strainers is unlikely. The mainline strainers for the foam fire suppression systems only experience flow during automatic system actuation and periodic flow testing or flushing. In addition, a review of the last ten (10) years of inspection results for Fire Protection System mainline strainers for the foam fire suppression systems (over 50 total inspections) has identified zero instances of flow blockage.

RS-14-078 Enclosure A Page 9 of 18 Fire Water System Inspection and Testing NFPA 25 Description Byron and Braidwood Fire Water System AMP Activities Section Based on the above, periodic inspections of strainers for foam fire suppression systems performed on a frequency of at least once every six (6) years is justified. If foreign material capable of causing flow blockage is identified it will be entered into the corrective action program and corrective actions will be taken, including potentially increasing the frequency of inspections, if appropriate.

In addition, at Byron the mainline strainers for the foam fire suppression systems are inspected when the system is reset after automatic system actuation. At Braidwood, the Fire Water System (B.2.1.16) aging management program will be enhanced to require strainer inspections when the system is reset after automatic system actuation. As a result of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 5 as shown in Enclosure C.

Spray nozzles for foam fire suppression subsystems are visually inspected for obstructions at least once per refueling cycle during periodic surveillance activities (e.g., alarm testing).

In addition, the existing program includes air flow testing of the foam fire suppression subsystems Operational Test to ensure that nozzles are not obstructed. Air flow testing of the foam fire suppression systems is Discharge Patterns 11.3.2.6 performed at least once every three (3) years. The three (3) year frequency is consistent with the (annually) requirements of NFPA 25, Section 13.4.3.2.2.4. The testing frequency for individual foam fire suppression subsystems is based on prior testing results. If plugging or flow blockage is identified it is entered into the corrective action program and corrective actions are taken, including potentially increasing the frequency of testing, if appropriate.

Visual inspections of the internal surface of the foam concentrate tanks are currently performed Visual every 15 years. The program will be enhanced to perform visual inspections of the internal surface Storage tanks inspection of the foam concentrate tanks on a ten (10) year frequency. As a result of this change, LRA (internal - 10 years) for internal Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron corrosion and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 6 as shown in Enclosure C.

RS-14-078 Enclosure A Page 10 of 18 Fire Water System Inspection and Testing NFPA 25 Description Byron and Braidwood Fire Water System AMP Activities Section Obstruction Investigation The Fire Water System (B.2.1.16) aging management program provides for flushing and flow testing of water-based fire suppression systems to detect and prevent flow blockage. In addition, visual inspections of system piping are performed for degradation and evidence of flow blockage when the piping is made accessible during routine maintenance activities (e.g., strainer inspections, valve inspections or replacements, trim piping inspections). To confirm flow blockage in the Fire Protection System is not occurring, the Fire Water System (B.2.1.16) aging management program will be enhanced to include non-destructive examinations capable of Obstruction, 14.2 and detecting internal flow blockage (e.g., digital radiography) or internal visual inspections, every five internal inspection 14.3 (5) years. Visual inspections will be performed by opening a flushing connection at the end of one of piping (1) main and by removing a sprinkler toward the end of one (1) branch line in each structure containing in-scope water-based fire suppression systems. Evidence of internal flow blockage will be entered into the corrective action program. If internal flow blockage that could result in failure of the system to deliver the required flow is identified, then an obstruction investigation will be performed. As a result of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 7 as shown in Enclosure C.

RS-14-078 Enclosure A Page 11 of 18

2. Wall thickness evaluations will not be used in lieu of conducting inspections for flow blockage (i.e., non-destructive examinations capable of detecting flow blockage or internal visual inspections) or flow tests. Flow testing or inspections for flow blockage will be performed as described in response to Request 1. Wall thickness measurements will be performed to monitor the condition of the piping and provide reasonable assurance that age-related degradation of the piping will be managed such that minimum wall thickness will be maintained. As a result, LRA Section B.2.1.16 is revised as shown in Enclosure B of this response to clarify that wall thickness evaluations will not be used in lieu of conducting flow tests or inspections for flow blockage.

3. The internal visual inspections required by the Fire Water System (B.2.1.16) aging management program are primarily intended to detect internal flow blockage rather than loss of material. Detection of loss of material is provided for by periodic volumetric examinations of system piping, flow testing, leakage testing, and external inspections for indications of system leakage. Performance of these aging management activities provide reasonable assurance that the pressure boundary intended function of Fire Protection System components is maintained consistent with the current licensing basis through the period of extended operation. In addition, existing procedures require the as-found condition of the piping to be documented, including quantification of deposit accumulation and localized wall loss during internal visual inspections. The condition of the piping is characterized with regard to the accumulation of deposits, biomass, corrosion, etc. Noticeable deposits in excess of a normal oxide layer, which could be indicative of wall loss below nominal, are documented. If tubercles are present, they are sampled and preserved for analysis. Inspection results that are unusual or unexpected (e.g., surface irregularities indicative of significant loss of material) are documented in the corrective action program for evaluation. 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.

The results of prior inspections of Fire Protection System piping are captured in an inspection database for trending and for determination of locations of future periodic volumetric examinations. Fire Protection System piping is risk ranked based on susceptibility of corrosion and consequences of leaks to determine locations for inspection. Corrosion susceptibility is determined based on many factors including flow conditions, material, piping size, configuration, and the results of prior inspections (including the guided wave survey). The consequence of leaks considers the safety and production consequences, and considers the impact of leakage or spray on nearby safety-related and production-related equipment.

4. 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) Flow testing or visual inspections of the internal surface of portions of the system that meet the above criteria will be 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.

RS-14-078 Enclosure A Page 12 of 18 (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 (5) 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.

(f) As stated above in Part (d), 20% of the 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, will be subjected to volumetric examinations on a five (5) year frequency.

As a result of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 8 as shown in Enclosure C.

5. As a result of the response to this RAI, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B of this response. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised as shown in Enclosure C.

RS-14-078 Enclosure A Page 13 of 18 RAI B.2.1.16-2, Guided wave and ultrasonic inspections of fire water system components Applicability: Byron

Background:

The operating experience program element of LRA Section B.2.1.16, Fire Water System states that Byron performed an analysis in March 2007 to identify any common causes for the 14 through-wall leaks that were identified in the fire water system between January 2002 and January 2007. The analysis concluded that the likely cause of the leaks was microbiologically-induced corrosion (MIC).

Enhancement No 2 to the program will [p]rovide 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. In addition, the LRA states that guided wave inspections are used to identify locations of potential wall thinning caused by MIC and follow-up ultrasonic examinations are performed to determine if piping replacement is required.

Issue:

The corrective actions associated with the leaks that have occurred in the fire water system included guided wave and ultrasonic examinations. The LRA states, [f]ollow-up ultrasonic testing is performed at locations identified by the guided wave inspections to determine if replacement of piping is required. It appears to the staff that the corrective actions may have been effective to date because they include chemical treatments to mitigate the spread of MIC and inspections to appropriately identify components that should be replaced. Although the program basis document states that non-intrusive inspections are performed on a representative number of locations, the staff notes that the implementing procedures for the Fire Water System program do not specify the current process of using guided wave and ultrasonic examinations and do not include a minimum number of inspections to be conducted.

Request:

In regard to guided wave testing in conjunction with ultrasonic wall thickness measurement, provide details showing that the current implementing procedures reflect the use of this technique and that these examinations include the most susceptible portions of the system.

Also provide details showing that the current implementing procedures include a minimum number of locations to be inspected at the current frequency of 3 years.

If the above information is not included in the current implementing procedures, either provide the basis to demonstrate that, without this information in the implementing procedures, the effects of aging will be adequately managed by the Fire Water System program so that the intended functions of the associated components will be maintained consistent with the CLB for the PEO, or provide an enhancement to revise the current implementing procedures to reflect the above information.

RS-14-078 Enclosure A Page 14 of 18 Exelon Response:

In March 2007, a common cause analysis was performed in response to fourteen (14) through-wall leakage events in the Fire Protection System at Byron between January 2002 and January 2007. The common cause analysis identified microbiologically influenced corrosion (MIC) as the most likely cause for the majority of the leakage events. The Exelon raw water corrosion program allows for the use of guided wave examinations as a non-destructive screening methodology to identify potential areas of general and localized loss of material. A one-time guided wave survey of the water-filled Fire Protection System piping was performed as part of the corrective actions taken to address these leakage events. The result of the guided wave survey was used to determine locations of potential wall-thinning caused by MIC. Follow-up ultrasonic testing (UT) of locations identified in the guided wave survey has been performed.

Additional corrective actions, up to and including repair and replacement of piping, have been performed in locations where follow-up ultrasonic testing indicated significant loss of material.

Ongoing periodic guided wave inspections, however, are not credited as qualified inspections as part of the Fire Water System (B.2.1.16) aging management program.

Ongoing periodic ultrasonic testing of Fire Protection System piping is performed to ensure that MIC is identified prior to loss of system function. Ultrasonic testing of Fire Protection System piping is performed utilizing a 100% scan method rather than a point-to-point grid UT method to ensure that the localized MIC aging mechanism is detected. Fire Protection System piping is risk ranked based on susceptibility of corrosion and consequences of leaks to determine locations for inspection. Corrosion susceptibility is determined based on many factors including flow conditions, material, piping size, configuration, and the results of prior inspections (including the guided wave survey). The consequence of leaks considers the safety and production consequences, and considers the impact of leakage or spray on nearby safety-related and production-related equipment. The preceding guidance is provided in existing station procedures, however, no specific procedural guidance is currently provided that identifies the minimum number of locations to be inspected. Therefore, the Fire Water System (B.2.1.16) aging management program will be enhanced to require a minimum of 30 UTs of Fire Protection System piping every three (3) years at Byron Station.

As a result of this change, LRA Sections A.2.1.16 and B.2.1.16 are revised as shown in Enclosure B. The Byron and Braidwood LRA Table A.5 Commitment List, Item 16, is also revised to add Enhancement 9 as shown in Enclosure C.

RS-14-078 Enclosure A Page 15 of 18 RAI 3.1.2.3-1 Aging management of core barrel assembly (barrel plates and nozzles)

Applicability: Byron and Braidwood

Background:

LRA Table 3.1.2-3 indicates that the core barrel assembly (barrel plates and nozzles) will be managed by the PWR Vessel Internals Program for the effects of changes in dimension, cracking and loss of fracture toughness. The staff noted that Section 4 of MRP-227-A and LRA Appendix C do not identify the core barrel assembly (barrel plates and nozzles) in the primary, expansion or existing program inspection categories. The staff also noted that MRP-191 does not identify the core barrel assembly (barrel plates and nozzles) as categorized as a Category A component.

Issue:

Since the core barrel assembly (barrel plates and nozzles) is not identified in LRA Appendix C, Section 4 of MRP-227-A or MRP-191, it is not clear to the staff how the PWR Vessel Internals Program will be used to manage the effects of changes in dimension, cracking and loss of fracture toughness in these components. Specifically, the applicant has not identified the details of the inspection for these components, including details on the inspection category, inspection method, frequency, coverage and acceptance criteria, expansion link, and, any additional programmatic criteria.

Request:

• Explain and justify how the core barrel assembly (barrel plates and nozzles) will be managed for effects of changes in dimension, cracking and loss of fracture toughness by the PWR Vessel Internals Program. The response should address, but is not limited to, the inspection category, inspection method, frequency, coverage and acceptance criteria, expansion link, and, any additional programmatic criteria associated with the inspection.

• Revise the LRA, as necessary (e.g., LRA Table 3.1.2-3, LRA Appendix B.2.1.7, response to Applicant/Licensee Action Item No. 2, LRA Appendix C).

Exelon Response:

• The core barrel assembly is a large welded structure consisting of an upper core barrel and lower core barrel. The upper and lower core barrel cylinders are fabricated from welded plates. The upper core barrel includes the outlet nozzles and is welded at the top to the core barrel flange. The lower core barrel is welded to the core support plate (lower support forging). A circumferential weld joins the upper core barrel and lower core barrel together. The core barrel assembly (barrel plates and nozzles) will be managed for effects of change in dimension, cracking, and loss of fracture toughness through the inspection of the various associated core barrel welds listed in LRA Appendix C, Tables A and B.

The associated core barrel assembly welds include:

- Core Barrel Assembly: Lower Core Barrel Flange Weld,

- Core Barrel Assembly: Upper Core Barrel Flange Weld,

RS-14-078 Enclosure A Page 16 of 18

- Core Barrel Assembly: Upper and Lower Core Barrel Cylinder Girth Welds,

- Core Barrel Assembly: Core Barrel Axial Welds, and

- Core Barrel Assembly: Core Barrel Outlet Nozzle Welds.

The examination coverage of the welds, listed above, includes the adjacent base metal, which includes the core barrel plates and nozzles. The inspection category, inspection method, frequency, coverage and acceptance criteria, and expansion link are defined in LRA Appendix C for the various associated core barrel welds.

• No changes to the LRA are required as a result of this response.

RS-14-078 Enclosure A Page 17 of 18 RAI 3.1.2.3-2, Aging management of core barrel assembly (upper and lower core barrel cylinder girth welds)

Applicability: Byron and Braidwood

Background:

Table A of LRA Appendix C identifies the Core Barrel Assembly: Upper and Lower Core Barrel Cylinder Girth Welds as being managed for the effects of cracking, loss of fracture toughness and changes in dimensions as a primary inspection category component in the PWR Vessel Internals Program.

Table B of LRA Appendix C identifies the Lower Internals Assembly: Lower Support Forging as being managed for the effects of cracking, loss of fracture toughness and changes in dimensions as an expansion inspection category component in the PWR Vessel Internals Program.

Issue:

The staff noted that both components were identified as being inspected by the PWR Vessel Internals Program; however, neither of the components discussed above was identified by the applicant in its aging management review results in LRA Table 3.1.2-3. In accordance with 10 CFR 54.21(a)(1) and (a)(3), the applicant is to identify and list those structures and components subject to an aging management review and demonstrate that the effects of aging on these components will be adequately managed for the PEO, respectively.

Request:

• Justify the discrepancy described above between LRA Table 3.1.2-3 and Tables A and B in LRA Appendix C. If necessary, revise LRA Table 3.1.2-3.

• Confirm that all reactor vessel internals components that are within the scope of license renewal and subject to aging management are identified in LRA Section 3.1. This is to include, but is not limited to, components in the primary, expansion, existing program and no additional measure inspection categories of the PWR Vessel Internals Program.

o If the applicable components are not identified, revise LRA Section 3.1 accordingly or justify that revisions are not needed to identify all reactor vessel internals components that are subject to an aging management review and to demonstrate that the effects of aging on these components will be adequately managed for the period of extended operation in accordance with 10 CFR 54.21(a)(1) and (a)(3), respectively.

Exelon Response:

• LRA Table 3.1.2-3 is updated to include line items for the Core Barrel Assembly: Upper and Lower Core Barrel Cylinder Girth Welds and Lower Internals Assembly: Lower Support Forging to establish consistency between LRA Table 3.1.2-3 and Tables A and B in LRA Appendix C.

RS-14-078 Enclosure A Page 18 of 18 LR-ISG-2011-04, Updated Aging Management Criteria for Reactor Vessel Internal Components for Pressurized Water Reactors, was used as guidance for the line item selection.

Changes to LRA Table 3.1.2-3 are provided in Enclosure B.

• A review of the items listed in LRA Table 3.2.1-3 determined all the components classified as Primary, Expansion, or Existing Program and applicable to Byron and Braidwood Station, Units 1 and 2, are accounted for in LRA Table 3.1.2-3 with the exception of the items discussed above. This review also determined that not all of the components classified as No Additional Measures and applicable to Byron and Braidwood Station, Units 1 and 2 are accounted for in the aging management review.

LRA Table 3.1.2-3 is updated to include the aging management review of the missing components. No changes to the PWR Vessel Internals Inspection Plan provided in LRA Appendix C were required as a result of this review.

LR-ISG-2011-04, Updated Aging Management Criteria for Reactor Vessel Internal Components for Pressurized Water Reactors, was used as guidance for the line item selection.

Changes to LRA Section 3.1.2.1.3 and Table 3.1.2-3 are provided in Enclosure B.

RS-14-078 Enclosure B Page 1 of 11 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.2.1.16-1 RAI B.2.1.16-2 RAI 3.1.2.3-2 Note: To facilitate understanding, the original LRA pages 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 strikethroughs for deleted text.

RS-14-078 Enclosure B Page 2 of 11 As a result of the responses to RAI B.2.1.16-1 and RAI B.2.1.16-2 provided in Enclosure A of this letter, LRA Appendix A, Section A.2.1.16, pages A-21 and A-22, is revised as shown below.

Pre-existing text from the LRA is formatted in normal font. Additions are indicated with bolded italics.

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 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.

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.

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.

RS-14-078 Enclosure B Page 3 of 11 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) 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.

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).

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.

RS-14-078 Enclosure B Page 4 of 11 As a result of the responses to RAI B.2.1.16-1 and RAI B.2.1.16-2 provided in Enclosure A of this letter, LRA Appendix B, Section B.2.1.16, pages B-109 and B-110, is revised as shown below. Pre-existing text from the LRA is formatted in normal font. Additions are indicated with bolded italics; deletions are shown with strikethroughs.

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.

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 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 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 (1) pipe wall thickness to ensure against loss of system intended function and (2) the inner diameter of the

RS-14-078 Enclosure B Page 5 of 11 piping as it applies to the flow requirements of the fire protection system. 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.

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.

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.

RS-14-078 Enclosure B Page 6 of 11 (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 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

RS-14-078 Enclosure B Page 7 of 11 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) 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. 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)

RS-14-078 Enclosure B Page 8 of 11 As a result of changes to the PWR Vessel Internals aging management program identified in the response to 3.1.2.3-2, LRA Section 3.1.2.1.3, page 3.1-4, is revised as shown below. Revisions are indicated with bold italics for inserted text:

3.1.2.1.3 Reactor Vessel Internals Materials The materials of construction for the Reactor Vessel Internals components are:

• Cast Austenitic Stainless Steel

• Nickel Alloy

• Stainless Steel

• Stainless Steel Bolting

RS-14-078 Enclosure B Page 9 of 11 As a result of changes to the PWR Vessel Internals aging management program identified in the response to 3.1.2.3-2, LRA Table 3.1.2-3, page 3.1-87, is revised as shown below. Revisions are indicated with bold italics for inserted text:

Table 3.1.2-3 Reactor Vessel Internals Component Type Intended Material Environment Aging Effect Aging Management NUREG-1801 Table 1 Notes Function Requiring Programs Item Item Management Core Barrel Assembly: Structural Support to Stainless Steel Reactor Coolant and Change in Dimension PWR Vessel Internals IV.B2.RP-270 3.1.1-59 D Core Barrel Axial Welds maintain core Neutron Flux (B.2.1.7) configuration and Cracking PWR Vessel Internals IV.B2.RP-387a 3.1.1-53 B flow distribution (B.2.1.7)

Water Chemistry (B.2.1.2) IV.B2.RP-387a 3.1.1-53 A Loss of Fracture PWR Vessel Internals IV.B2.RP-388a 3.1.1-59 B Toughness (B.2.1.7)

Loss of Material Water Chemistry (B.2.1.2) IV.B2.RP-24 3.1.1-87 A As a result of changes to the PWR Vessel Internals aging management program identified in the response to 3.1.2.3-2, LRA Table 3.1.2-3, page 3.1-88, is revised as shown below. Revisions are indicated with bold italics for inserted text:

Table 3.1.2-3 Reactor Vessel Internals (continued)

Component Type Intended Material Environment Aging Effect Aging Management NUREG-1801 Table 1 Notes Function Requiring Programs Item Item Management Core Barrel Assembly: Structural Support Stainless Steel Reactor Coolant and Change in Dimension PWR Vessel Internals IV.B2.RP-270 3.1.1-59 D Upper and Lower Core to maintain core Neutron Flux (B.2.1.7)

Barrel Cylinder Girth configuration and Cracking PWR Vessel Internals IV.B2.RP-387 3.1.1-53 B Welds flow distribution (B.2.1.7)

Water Chemistry IV.B2.RP-387 3.1.1-53 A (B.2.1.2)

Loss of Fracture PWR Vessel Internals IV.B2.RP-388 3.1.1-59 B Toughness (B.2.1.7)

Loss of Material Water Chemistry IV.B2.RP-24 3.1.1-87 A (B.2.1.2)

RS-14-078 Enclosure B Page 10 of 11 As a result of changes to the PWR Vessel Internals aging management program identified in the response to 3.1.2.3-2, LRA Table 3.1.2-3, page 3.1-91, is revised as shown below. Revisions are indicated with bold italics for inserted text:

Table 3.1.2-3 Reactor Vessel Internals (continued)

Component Type Intended Material Environment Aging Effect Aging Management NUREG-1801 Table 1 Notes Function Requiring Programs Item Item Management Lower Internals Structural Support Stainless Steel Reactor Coolant and Change in Dimension PWR Vessel Internals IV.B2.RP-270 3.1.1-59 D Assembly: Lower to maintain core Neutron Flux (B.2.1.7)

Support Forging configuration and Cracking PWR Vessel Internals IV.B2.RP-291a 3.1.1-53 B flow distribution (B.2.1.7)

Water Chemistry IV.B2.RP-291a 3.1.1-53 A (B.2.1.2)

Loss of Fracture PWR Vessel Internals IV.B2.RP-290a 3.1.1-59 B Toughness (B.2.1.7)

Loss of Material Water Chemistry IV.B2.RP-24 3.1.1-87 A (B.2.1.2)

As a result of changes to the PWR Vessel Internals aging management program identified in the response to 3.1.2.3-2, LRA Table 3.1.2-3, page 3.1-93, is revised as shown below. Revisions are indicated with bold italics for inserted text:

Table 3.1.2-3 Reactor Vessel Internals (continued)

Component Type Intended Material Environment Aging Effect Aging Management NUREG-1801 Table 1 Notes Function Requiring Programs Item Item Management Reactor Vessel Internals Structural Support Stainless Steel, Reactor Coolant and No additional aging PWR Vessel Internals IV.B2.RP-265 3.1.1-59 A, 5 Components (Various to maintain core Nickel Alloy, Neutron Flux management for reactor (B.2.1.7)

No Additional configuration and Cast Austenitic internal No Additional Measures flow distribution Stainless Steel Measures components Components) unless required by ASME Section XI, Examination Category B-N-3 or relevant operating experience exists

RS-14-078 Enclosure B Page 11 of 11 As a result of changes to the PWR Vessel Internals aging management program identified in the response to 3.1.2.3-2, LRA Table 3.1.2-3, page 3.1-95, is revised as shown below. Revisions are indicated with bold italics for inserted text:

Plant Specific Notes:

5. Various reactor vessel internal components with a final classification of No Additional Measures. No Additional Measures are indicated as Category A components in MRP-191, Table 7-2, Categorization of Westinghouse Reactor Internals Components or as Final Group N in MRP-227-A, Table 3-3, Final Disposition of Westinghouse Internals.

RS-14-078 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 NRCs 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.2.1.16-1 RAI B.2.1.16-2 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 in bold italics for inserted text.

RS-14-078 Enclosure C Page 2 of 3 As a result of the responses to RAI B.2.1.16-1 and RAI B.2.1.16-2 provided in Enclosure A of this letter, LRA Appendix A, Table A.5 License Renewal Commitment List, line item 16 on page A-76, is revised as shown below. Pre-existing text, from the LRA is formatted in normal font. Additions are indicated with bolded italics.

A.5 LICENSE RENEWAL COMMITMENT LIST PROGRAM OR IMPLEMENTATION NO. COMMITMENT SOURCE TOPIC SCHEDULE 16 Fire Water Fire Water is an existing program that will be enhanced to: Program to be enhanced prior Section A.2.1.16 to the period of extended

1. Replace sprinkler heads or perform 50-year sprinkler head testing operation. Exelon letter using the guidance of NFPA 25 Standard for the Inspection, RS-14-078 Testing and Maintenance of Water-Based Fire Protection Inspection schedule identified 03/13/2014 Systems (2002 Edition), Section 5.3.1.1.1. This testing will be in commitment.

performed at the 50-year in-service date and every 10 years thereafter. RAI B.2.1.16-1 RAI B.2.1.16-2

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 Note 3 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)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)

Note 1 (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.

RS-14-078 Enclosure C Page 3 of 3 PROGRAM OR IMPLEMENTATION NO. COMMITMENT SOURCE TOPIC SCHEDULE

7. Perform non-destructive examinations capable of detecting internal flow blockage (e.g., digital radiography) 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. 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 Note 3 (Byron only) .