ML15308A100

Public Meeting Presentation Slides Extended Power Uprate License Amendment Request NRC Public Meeting

ML15308A100
Person / Time
Site:	Browns Ferry
Issue date:	11/10/2015
From:	Doyle G Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation
Saba F, NRR/DORL, 415-1447
References
Download: ML15308A100 (37)

Text

Browns Ferry Nuclear Plant Extended Power Uprate License Amendment Request NRC Public Meeting Gerry Doyle Director EPU November 10, 2015

BFN EPU - Agenda Introductions G Doyle Extended Power Uprate (EPU) Overview G Doyle Submittal Format and Content/Approach D Green Disposition of Pre-Application Meetings Feedback D Green Electronic Reading Room D Green Proposed Audit Schedule D Green Acceptance Review Issues

• Replacement Steam Dryers P Donahue

• Containment Accident Pressure Credit Elimination P Donahue

• Spent Fuel Pool Criticality Analysis G Storey/J Kimberlin

• Analysis Code MICROBURN-B2 G Storey Questions/Comments G Doyle Browns Ferry EPU License Amendment Request l 2

BFN EPU - Introductions Gerry Doyle - Director, Extended Power Uprate (EPU)

Pete Donahue - EPU Engineering Manager Dan Green - EPU Licensing Manager Jeff Kimberlin - EPU Operations Support Manager Ed Schrull - Fleet Licensing Manager Greg Storey - Fleet BWR Fuels Engineering Manager Browns Ferry EPU License Amendment Request l 3

BFN EPU - Overview Browns Ferry EPU License Amendment Request l 4

BFN EPU - Submittal Format and Content/Approach New Consolidated License Amendment Request (LAR) Submittal Supersedes all previous Browns Ferry Nuclear Plant (BFN) Extended Power Uprate (EPU) submittals

- Previous submittals withdrawn

- Addresses current BFN conditions Format of RS-001, Review Standard for Extended Power Uprates Applied Lessons Learned

- Previous applicable NRC Requests for Additional Information addressed in new submittal Includes replacement of Steam Dryers Includes resolution of Containment Accident Pressure issue

- In accordance with SECY 11-0014, Use of Containment Accident Pressure in Analyzing Emergency Core Cooling System and Containment Heat Removal System Pump Performance in Postulated Accidents, guidance Applied improved submittal Verification and Validation process

- To ensure completeness and accuracy Browns Ferry EPU License Amendment Request l 5

BFN EPU - Submittal Format and Content/Approach (continued)

Applied Institute of Nuclear Power Operations (INPO)

Operating Experience (OE)

- Significant Event Report (SER) 5-02, Lessons Learned from Power Uprates

- INPO 09-005, Power Uprate Implementation Strategies - A Leadership Perspective

- INPO Event Report (IER) 14-20, Integrated Risk - Healthy Technical Conscience Applied results of Benchmarking

- Benchmarking of recent Boiling Water Reactor (BWR) Licensees with EPU LARs Monticello, Grand Gulf, Peach Bottom Applied BWR Owners Group (BWROG) Lessons Learned

- BWROG-TP-043, BWR Owners Group EPU Committee -

Extended Power Uprate (EPU) Lessons Learned and Recommendations Browns Ferry EPU License Amendment Request l 6

BFN EPU - Disposition of Pre-application Meetings Feedback Browns Ferry EPU License Amendment Request l 7

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 8

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 9

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 10

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 11

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 12

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 13

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 14

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 15

BFN EPU - Electronic Reading Room

• Facilitates NRC review Allows file sharing (e.g., calculations) with NRC reviewers Files may be opened and viewed by NRC reviewers, but copying, printing or downloading files is precluded Will not be used for Requests for Additional Information (RAIs)

- Normal NRC process will be used for RAIs

• URL for reading room portal https://bfepurr.certrec.com

• Access to reading room restricted to those NRC personnel granted access BFN reading room administrator grants specific NRC personnel access to the reading room

- Need NRC reviewer names and email addresses to assign user names and passwords

• Process NRC requests information to review (e.g., calculation)

Information is obtained and file uploaded by BFN reading room administrator After file is uploaded, an email is generated to NRC (Project Manager or reviewer, as determined by NRC), informing them that information is available for review If, after reviewing the reading room file, NRC determines information from file is needed, the Tennessee Valley Authority will submit the required information on the docket Browns Ferry EPU License Amendment Request l 16

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 17

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 18

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 19

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 20

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 21

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 22

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 23

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 24

BFN EPU - Proposed Audit Schedule

• Regulatory audits allow NRC to more efficiently conduct its review or gain insights on a licensees programs or processes

• Regulatory audits are conducted with the intent for the NRC to gain understanding, to verify information, and/or to identify information that will require docketing to support the basis of the licensing or regulatory decision Proposed audit schedule to facilitate NRC review of EPU LAR

- Replacement Steam Dryer Design and Analyses February 8 - 12, 2016

- Containment Accident Pressure Credit Elimination Analyses March 14 - 18, 2016

- Fuels Analyses March 21 - 25, 2016

- Other Audits, as needed Browns Ferry EPU License Amendment Request l 25

BFN EPU - Acceptance Review Issues

• Replacement Steam Dryers Analysis Methodology

- BFN Replacement Steam Dryer (RSD) acoustic load definition was developed using the GEH Plant Based Load Evaluation Methods

- For BFN, one acoustic load definition was developed that bounds the loading for all three BFN units

- The RSD for the initial unit at EPU conditions will have on-dryer instrumentation such that actual RSD loading can be compared to predicted loads Acoustic Vibration Suppressors (AVSs)

- AVSs were designed and installed on all three BFN units to reduce the depth of the standpipe cavity and eliminate an excessive resonance source

- Main Steam Line (MSL) strain gauge data, taken after the installation of the AVSs, shows that the acoustic resonance associated with the standpipes has been eliminated

- Stress analyses for the BFN RSDs used MSL acoustic data for each BFN unit taken with the AVSs installed Browns Ferry EPU License Amendment Request l 26

BFN EPU - Acceptance Review Issues

• Replacement Steam Dryers (continued)

Acoustic Side Branches (ASBs)

- BFN does not currently experience any significant resonances associated with the Safety Relief Valve (SRV) standpipes requiring ASB installation at BFN However, based on analyses, it is predicted that SRV resonance could occur at the increased steam flow velocities for EPU

- SRV resonance at BFN EPU conditions is addressed in the BFN SDAR (NEDC-33824P, EPU LAR Attachment 40)

- In addition, monitoring of main steam system piping vibration and SRV vibration at EPU conditions will be performed in accordance with the Flow Induced Vibration Analysis and Monitoring Program (EPU LAR Attachment 45)

Browns Ferry EPU License Amendment Request l 27

BFN EPU - Acceptance Review Issues

• Containment Accident Pressure Credit Elimination Residual Heat Removal Heat Exchanger Thermal Performance Testing

- EPU Design Fouling Resistance is 0.001521

- EPU Nominal Fouling Resistance (Fire Event) is 0.001097

• Preliminary results Browns Ferry EPU License Amendment Request l 28

BFN EPU - Acceptance Review Issues

• Spent Fuel Pool Criticality Analysis Fuel Uprate Safety Analysis Report (FUSAR) (EPU LAR Attachment 8) section 2.8.6.2 addresses spent fuel storage

- Summarizes results of the criticality safety analyses (CSA) of record

- AREVA fuel types that will reside in EPU cores evaluated BFN CSA reports comply with the requirements of DSS-ISG-2010-01, Staff Guidance Regarding the Nuclear Safety Analysis for Spent Fuel Pools CSAs included sensitivity studies for parameters potentially affected by EPU

- Power density sensitivity

+/- 50% variation in power density for a fixed void fraction Higher power density resulted in lower in rack k-infinity (k)

- Void history sensitivity Range of void histories between 0% and 90% studied Limiting void history used in the CSA High void history not limiting (typically 0% void history limiting)

- Control history sensitivity Uncontrolled history produces the limiting result No EPU impacts Browns Ferry EPU License Amendment Request l 29

BFN EPU - Acceptance Review Issues

• Spent Fuel Pool Criticality Analysis (continued)

- Fuel temperature sensitivity

+/- 100°F variation in fuel temperature In rack k shown to be insensitive to operating fuel temperature

- Power shape sensitivity No impact from EPU Lattices evaluated at the limiting exposure and void history combination

- Pool temperature sensitivity Higher decay heat from EPU operation could raise pool temperature Evaluation showed minimum pool temperature limiting Conclusions

- Parameters potentially affected by EPU operation studied

- CSA reports of record are applicable and conservative for EPU Browns Ferry EPU License Amendment Request l 30

BFN EPU - Acceptance Review Issues

• Spent Fuel Pool Criticality Analysis (continued)

Additional controls to prevent criticality during fuel movement

- Reactor Engineering creates Fuel Assembly Transfer Form (FATF), based on CSA

- Fuel moves are verified and tracked to be in accordance with FATF by the following Performer Concurrent Verifier A Senior Reactor Operator on the refuel bridge A Reactor Engineer on the refuel floor Separate individual at a remote location using installed camera on refueling bridge A Licensed Operator in the Control Room

- FATF requirements are input into the Bridge and Trolley Tracking System (BATTS) prior to fuel movement BATTS provides alternate indication/alarm when performing fuel movements in the reactor core or spent fuel pool Browns Ferry EPU License Amendment Request l 31

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 AREVA identified an issue with the MICROBURN-B2 analysis

- Related to convergence of the thermal hydraulic solution at low core flows

- Affects the version of the code used to support the BFN EPU LAR Nature of the issue

- Calculation of the bypass flow at low core flow conditions can oscillate between two values without reaching convergence (maximum iterations reached)

Presence of voiding in the upper bypass creates the convergence difficulties

- Code will continue to run with the unconverged hydraulic solution

- Results in the axial power shape not being correct in MICROBURN-B2

- Problem observed for core flows < 40% of rated Extent of condition

- Investigations show the thermal hydraulic stability analysis is affected Incorrect axial power shape affects stability results

- Flow dependent Critical Power Ratio (CPR) and Linear Heat Generation Rate limits include cases below 40% core flow Evaluations show these two analyses are not affected for EPU LAR

- All other analyses in the EPU LAR that involve MICROBURN-B2 are performed at core flows of 50% and higher

- FUSAR and Unit 3 Cycle 19 EPU Representative Reload Report affected Browns Ferry EPU License Amendment Request l 32

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 (continued)

Effect on FUSAR (ANP-3403P) (EPU LAR Attachment 8)

- Generic Delta Critical Power Ratio (CPR) over Initial Minimum CPR (MCPR)

Versus Oscillation Magnitude (DIVOM) line presented in Figure 2.8-3 will still be bounding Calculated points below the line will change slightly

- Small changes to decay ratio values in Tables 2.8-2 and 2.8-3 Backup Stability Protection region boundaries remain the same

- Operating limit CPR values presented in Table 2.8-1 will decrease slightly Values in current FUSAR report are conservative Stability will continue to not set the overall CPR operating limit when the analysis is rerun Effect on Unit 3 Cycle 19 EPU Representative Reload Report (ANP-3404P)

(EPU LAR Attachment 20)

- Operating limit CPR values presented in Table 4.3 decrease slightly Values in current revision of the report are conservative Stability will continue to not set the overall CPR operating limit when the analysis is rerun Corrective actions to prevent recurrence

- Improved convergence scheme in MICROBURN-B2 for low flow cases

- Message will be written to error file if the condition should occur Browns Ferry EPU License Amendment Request l 33

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 (continued)

AREVA identified a second issue during investigation of the MICROBURN-B2 flow convergence problem

- Related to application of the void quality correlation at low core flows Nature of the issue

- Void quality correlation used in the EPU LAR work has a low mass flux cutoff

- Cutoff is used to preclude non-physical results for calculations where very high quality conditions may occur (Anticipated Transient Without Scram with Core Instability)

- Cutoff may not be appropriate for calculations with low to moderate quality conditions Extent of condition

- Similar to the flow convergence issue, stability analysis may be affected Difference in results is on the order of normal cycle to cycle variation in results

- Other events at low flow shown not to be affected by this issue

- FUSAR and Unit 3 Cycle 19 EPU Representative Reload Report affected Corrective actions to prevent recurrence

- Issue still in discovery

- Corrective actions will be defined when discovery has been completed Browns Ferry EPU License Amendment Request l 34

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 (continued)

Browns Ferry EPU LAR Supplement

- Interim Report, addressing both issues, expected to be submitted by November 9, 2015 Supports continuing EPU LAR acceptance reviews

- Revised FUSAR and Unit 3 Cycle 19 EPU Representative Reload Report, addressing both issues, expected to be submitted by December 15, 2015 Browns Ferry EPU License Amendment Request l 35

BFN EPU - Acronym List

• ACRS - Advisory Committee on Reactor Safeguards

• IN - Information Notice

• ASBs - Acoustic Side Branches

• INPO - Institute of Nuclear Power Operations

• ATWS - Anticipated Transient Without Scram

• LA - License Amendment

• AVSs - Acoustic Vibration Suppressors

• LAR - License Amendment Request

• BATTS - Bridge and Trolley Tracking System

• LERF - Large Early Release Frequency

• BFN - Browns Ferry Nuclear Plant

• MAPLHGR - Maximum Average Planar Linear Heat

• Btu - British Thermal Unit Generation Rate

• BWR - Boiling Water Reactor

• MCPR - Minimum Critical Power Ratio

• BWROG - BWR Owners Group

• MSL - Main Steam Line

• CAP - Containment Accident Pressure

• MWt - Megawatt Thermal

• CDF - Core Damage Frequency

• NPSH - Net Positive Suction Head

• CPR - Critical Power Ratio

• NRC - Nuclear Regulatory Commission

• CRDA - Control Rod Drop Accident

• OE - Operating Experience

• CSA - Criticality Safety Analysis

• PCMI - Pellet-to-Cladding Mechanical Interaction

• DIVOM - Delta CPR over Initial MCPR Versus Oscillation

• PM - Preventive Maintenance Magnitude

• PRA - Probabilistic Risk Assessment

• ECCS - Emergency Core Cooling System

• PUSAR - Power Uprate Safety Analysis Report

• EHPMP - Emergency High Pressure Makeup Pump

• RAI - Request for Additional Information

• EPU - Extended Power Uprate

• RHR - Residual Heat Removal

• F - Farenheit

• RSD - Replacement Steam Dryer

• FATF - Fuel Assembly Transfer Form

• SDAR - Steam Dryer Analysis Report

• ft2 - square feet

• SE - Safety Evaluation

• FUSAR - Fuel Uprate Safety Analysis Report

• SER - Significant Event Report

• FIV - Flow Induced Vibration

• SLO - Single Loop Operation

• GDC - General Design Criteria

• SRP - Standard Review Plan

• hr - hour

• SRV - Safety Relief Valve

• HX - Heat Exchanger

• TIP - Traversing Incore Probe

• Hz - Hertz

• UFSAR - Updated Safety Analysis Report

• IER - INPO Event Report Browns Ferry EPU License Amendment Request l 36

BFN EPU - Questions/Comments Browns Ferry EPU License Amendment Request l 37

Browns Ferry Nuclear Plant Extended Power Uprate License Amendment Request NRC Public Meeting Gerry Doyle Director EPU November 10, 2015

BFN EPU - Agenda Introductions G Doyle Extended Power Uprate (EPU) Overview G Doyle Submittal Format and Content/Approach D Green Disposition of Pre-Application Meetings Feedback D Green Electronic Reading Room D Green Proposed Audit Schedule D Green Acceptance Review Issues

• Replacement Steam Dryers P Donahue

• Containment Accident Pressure Credit Elimination P Donahue

• Spent Fuel Pool Criticality Analysis G Storey/J Kimberlin

• Analysis Code MICROBURN-B2 G Storey Questions/Comments G Doyle Browns Ferry EPU License Amendment Request l 2

BFN EPU - Introductions Gerry Doyle - Director, Extended Power Uprate (EPU)

Pete Donahue - EPU Engineering Manager Dan Green - EPU Licensing Manager Jeff Kimberlin - EPU Operations Support Manager Ed Schrull - Fleet Licensing Manager Greg Storey - Fleet BWR Fuels Engineering Manager Browns Ferry EPU License Amendment Request l 3

BFN EPU - Overview Browns Ferry EPU License Amendment Request l 4

BFN EPU - Submittal Format and Content/Approach New Consolidated License Amendment Request (LAR) Submittal Supersedes all previous Browns Ferry Nuclear Plant (BFN) Extended Power Uprate (EPU) submittals

- Previous submittals withdrawn

- Addresses current BFN conditions Format of RS-001, Review Standard for Extended Power Uprates Applied Lessons Learned

- Previous applicable NRC Requests for Additional Information addressed in new submittal Includes replacement of Steam Dryers Includes resolution of Containment Accident Pressure issue

- In accordance with SECY 11-0014, Use of Containment Accident Pressure in Analyzing Emergency Core Cooling System and Containment Heat Removal System Pump Performance in Postulated Accidents, guidance Applied improved submittal Verification and Validation process

- To ensure completeness and accuracy Browns Ferry EPU License Amendment Request l 5

BFN EPU - Submittal Format and Content/Approach (continued)

Applied Institute of Nuclear Power Operations (INPO)

Operating Experience (OE)

- Significant Event Report (SER) 5-02, Lessons Learned from Power Uprates

- INPO 09-005, Power Uprate Implementation Strategies - A Leadership Perspective

- INPO Event Report (IER) 14-20, Integrated Risk - Healthy Technical Conscience Applied results of Benchmarking

- Benchmarking of recent Boiling Water Reactor (BWR) Licensees with EPU LARs Monticello, Grand Gulf, Peach Bottom Applied BWR Owners Group (BWROG) Lessons Learned

- BWROG-TP-043, BWR Owners Group EPU Committee -

Extended Power Uprate (EPU) Lessons Learned and Recommendations Browns Ferry EPU License Amendment Request l 6

BFN EPU - Disposition of Pre-application Meetings Feedback Browns Ferry EPU License Amendment Request l 7

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 8

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 9

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 10

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 11

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 12

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 13

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 14

BFN EPU - Disposition of Pre-application Meetings Feedback (continued)

Browns Ferry EPU License Amendment Request l 15

BFN EPU - Electronic Reading Room

• Facilitates NRC review Allows file sharing (e.g., calculations) with NRC reviewers Files may be opened and viewed by NRC reviewers, but copying, printing or downloading files is precluded Will not be used for Requests for Additional Information (RAIs)

- Normal NRC process will be used for RAIs

• URL for reading room portal https://bfepurr.certrec.com

• Access to reading room restricted to those NRC personnel granted access BFN reading room administrator grants specific NRC personnel access to the reading room

- Need NRC reviewer names and email addresses to assign user names and passwords

• Process NRC requests information to review (e.g., calculation)

Information is obtained and file uploaded by BFN reading room administrator After file is uploaded, an email is generated to NRC (Project Manager or reviewer, as determined by NRC), informing them that information is available for review If, after reviewing the reading room file, NRC determines information from file is needed, the Tennessee Valley Authority will submit the required information on the docket Browns Ferry EPU License Amendment Request l 16

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 17

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 18

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 19

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 20

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 21

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 22

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 23

BFN EPU - Electronic Reading Room (continued)

Browns Ferry EPU License Amendment Request l 24

BFN EPU - Proposed Audit Schedule

• Regulatory audits allow NRC to more efficiently conduct its review or gain insights on a licensees programs or processes

• Regulatory audits are conducted with the intent for the NRC to gain understanding, to verify information, and/or to identify information that will require docketing to support the basis of the licensing or regulatory decision Proposed audit schedule to facilitate NRC review of EPU LAR

- Replacement Steam Dryer Design and Analyses February 8 - 12, 2016

- Containment Accident Pressure Credit Elimination Analyses March 14 - 18, 2016

- Fuels Analyses March 21 - 25, 2016

- Other Audits, as needed Browns Ferry EPU License Amendment Request l 25

BFN EPU - Acceptance Review Issues

• Replacement Steam Dryers Analysis Methodology

- BFN Replacement Steam Dryer (RSD) acoustic load definition was developed using the GEH Plant Based Load Evaluation Methods

- For BFN, one acoustic load definition was developed that bounds the loading for all three BFN units

- The RSD for the initial unit at EPU conditions will have on-dryer instrumentation such that actual RSD loading can be compared to predicted loads Acoustic Vibration Suppressors (AVSs)

- AVSs were designed and installed on all three BFN units to reduce the depth of the standpipe cavity and eliminate an excessive resonance source

- Main Steam Line (MSL) strain gauge data, taken after the installation of the AVSs, shows that the acoustic resonance associated with the standpipes has been eliminated

- Stress analyses for the BFN RSDs used MSL acoustic data for each BFN unit taken with the AVSs installed Browns Ferry EPU License Amendment Request l 26

BFN EPU - Acceptance Review Issues

• Replacement Steam Dryers (continued)

Acoustic Side Branches (ASBs)

- BFN does not currently experience any significant resonances associated with the Safety Relief Valve (SRV) standpipes requiring ASB installation at BFN However, based on analyses, it is predicted that SRV resonance could occur at the increased steam flow velocities for EPU

- SRV resonance at BFN EPU conditions is addressed in the BFN SDAR (NEDC-33824P, EPU LAR Attachment 40)

- In addition, monitoring of main steam system piping vibration and SRV vibration at EPU conditions will be performed in accordance with the Flow Induced Vibration Analysis and Monitoring Program (EPU LAR Attachment 45)

Browns Ferry EPU License Amendment Request l 27

BFN EPU - Acceptance Review Issues

• Containment Accident Pressure Credit Elimination Residual Heat Removal Heat Exchanger Thermal Performance Testing

- EPU Design Fouling Resistance is 0.001521

- EPU Nominal Fouling Resistance (Fire Event) is 0.001097

• Preliminary results Browns Ferry EPU License Amendment Request l 28

BFN EPU - Acceptance Review Issues

• Spent Fuel Pool Criticality Analysis Fuel Uprate Safety Analysis Report (FUSAR) (EPU LAR Attachment 8) section 2.8.6.2 addresses spent fuel storage

- Summarizes results of the criticality safety analyses (CSA) of record

- AREVA fuel types that will reside in EPU cores evaluated BFN CSA reports comply with the requirements of DSS-ISG-2010-01, Staff Guidance Regarding the Nuclear Safety Analysis for Spent Fuel Pools CSAs included sensitivity studies for parameters potentially affected by EPU

- Power density sensitivity

+/- 50% variation in power density for a fixed void fraction Higher power density resulted in lower in rack k-infinity (k)

- Void history sensitivity Range of void histories between 0% and 90% studied Limiting void history used in the CSA High void history not limiting (typically 0% void history limiting)

- Control history sensitivity Uncontrolled history produces the limiting result No EPU impacts Browns Ferry EPU License Amendment Request l 29

BFN EPU - Acceptance Review Issues

• Spent Fuel Pool Criticality Analysis (continued)

- Fuel temperature sensitivity

+/- 100°F variation in fuel temperature In rack k shown to be insensitive to operating fuel temperature

- Power shape sensitivity No impact from EPU Lattices evaluated at the limiting exposure and void history combination

- Pool temperature sensitivity Higher decay heat from EPU operation could raise pool temperature Evaluation showed minimum pool temperature limiting Conclusions

- Parameters potentially affected by EPU operation studied

- CSA reports of record are applicable and conservative for EPU Browns Ferry EPU License Amendment Request l 30

BFN EPU - Acceptance Review Issues

• Spent Fuel Pool Criticality Analysis (continued)

Additional controls to prevent criticality during fuel movement

- Reactor Engineering creates Fuel Assembly Transfer Form (FATF), based on CSA

- Fuel moves are verified and tracked to be in accordance with FATF by the following Performer Concurrent Verifier A Senior Reactor Operator on the refuel bridge A Reactor Engineer on the refuel floor Separate individual at a remote location using installed camera on refueling bridge A Licensed Operator in the Control Room

- FATF requirements are input into the Bridge and Trolley Tracking System (BATTS) prior to fuel movement BATTS provides alternate indication/alarm when performing fuel movements in the reactor core or spent fuel pool Browns Ferry EPU License Amendment Request l 31

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 AREVA identified an issue with the MICROBURN-B2 analysis

- Related to convergence of the thermal hydraulic solution at low core flows

- Affects the version of the code used to support the BFN EPU LAR Nature of the issue

- Calculation of the bypass flow at low core flow conditions can oscillate between two values without reaching convergence (maximum iterations reached)

Presence of voiding in the upper bypass creates the convergence difficulties

- Code will continue to run with the unconverged hydraulic solution

- Results in the axial power shape not being correct in MICROBURN-B2

- Problem observed for core flows < 40% of rated Extent of condition

- Investigations show the thermal hydraulic stability analysis is affected Incorrect axial power shape affects stability results

- Flow dependent Critical Power Ratio (CPR) and Linear Heat Generation Rate limits include cases below 40% core flow Evaluations show these two analyses are not affected for EPU LAR

- All other analyses in the EPU LAR that involve MICROBURN-B2 are performed at core flows of 50% and higher

- FUSAR and Unit 3 Cycle 19 EPU Representative Reload Report affected Browns Ferry EPU License Amendment Request l 32

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 (continued)

Effect on FUSAR (ANP-3403P) (EPU LAR Attachment 8)

- Generic Delta Critical Power Ratio (CPR) over Initial Minimum CPR (MCPR)

Versus Oscillation Magnitude (DIVOM) line presented in Figure 2.8-3 will still be bounding Calculated points below the line will change slightly

- Small changes to decay ratio values in Tables 2.8-2 and 2.8-3 Backup Stability Protection region boundaries remain the same

- Operating limit CPR values presented in Table 2.8-1 will decrease slightly Values in current FUSAR report are conservative Stability will continue to not set the overall CPR operating limit when the analysis is rerun Effect on Unit 3 Cycle 19 EPU Representative Reload Report (ANP-3404P)

(EPU LAR Attachment 20)

- Operating limit CPR values presented in Table 4.3 decrease slightly Values in current revision of the report are conservative Stability will continue to not set the overall CPR operating limit when the analysis is rerun Corrective actions to prevent recurrence

- Improved convergence scheme in MICROBURN-B2 for low flow cases

- Message will be written to error file if the condition should occur Browns Ferry EPU License Amendment Request l 33

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 (continued)

AREVA identified a second issue during investigation of the MICROBURN-B2 flow convergence problem

- Related to application of the void quality correlation at low core flows Nature of the issue

- Void quality correlation used in the EPU LAR work has a low mass flux cutoff

- Cutoff is used to preclude non-physical results for calculations where very high quality conditions may occur (Anticipated Transient Without Scram with Core Instability)

- Cutoff may not be appropriate for calculations with low to moderate quality conditions Extent of condition

- Similar to the flow convergence issue, stability analysis may be affected Difference in results is on the order of normal cycle to cycle variation in results

- Other events at low flow shown not to be affected by this issue

- FUSAR and Unit 3 Cycle 19 EPU Representative Reload Report affected Corrective actions to prevent recurrence

- Issue still in discovery

- Corrective actions will be defined when discovery has been completed Browns Ferry EPU License Amendment Request l 34

BFN EPU - Acceptance Review Issues

• Analysis Code MICROBURN-B2 (continued)

Browns Ferry EPU LAR Supplement

- Interim Report, addressing both issues, expected to be submitted by November 9, 2015 Supports continuing EPU LAR acceptance reviews

- Revised FUSAR and Unit 3 Cycle 19 EPU Representative Reload Report, addressing both issues, expected to be submitted by December 15, 2015 Browns Ferry EPU License Amendment Request l 35

BFN EPU - Acronym List

• ACRS - Advisory Committee on Reactor Safeguards

• IN - Information Notice

• ASBs - Acoustic Side Branches

• INPO - Institute of Nuclear Power Operations

• ATWS - Anticipated Transient Without Scram

• LA - License Amendment

• AVSs - Acoustic Vibration Suppressors

• LAR - License Amendment Request

• BATTS - Bridge and Trolley Tracking System

• LERF - Large Early Release Frequency

• BFN - Browns Ferry Nuclear Plant

• MAPLHGR - Maximum Average Planar Linear Heat

• Btu - British Thermal Unit Generation Rate

• BWR - Boiling Water Reactor

• MCPR - Minimum Critical Power Ratio

• BWROG - BWR Owners Group

• MSL - Main Steam Line

• CAP - Containment Accident Pressure

• MWt - Megawatt Thermal

• CDF - Core Damage Frequency

• NPSH - Net Positive Suction Head

• CPR - Critical Power Ratio

• NRC - Nuclear Regulatory Commission

• CRDA - Control Rod Drop Accident

• OE - Operating Experience

• CSA - Criticality Safety Analysis

• PCMI - Pellet-to-Cladding Mechanical Interaction

• DIVOM - Delta CPR over Initial MCPR Versus Oscillation

• PM - Preventive Maintenance Magnitude

• PRA - Probabilistic Risk Assessment

• ECCS - Emergency Core Cooling System

• PUSAR - Power Uprate Safety Analysis Report

• EHPMP - Emergency High Pressure Makeup Pump

• RAI - Request for Additional Information

• EPU - Extended Power Uprate

• RHR - Residual Heat Removal

• F - Farenheit

• RSD - Replacement Steam Dryer

• FATF - Fuel Assembly Transfer Form

• SDAR - Steam Dryer Analysis Report

• ft2 - square feet

• SE - Safety Evaluation

• FUSAR - Fuel Uprate Safety Analysis Report

• SER - Significant Event Report

• FIV - Flow Induced Vibration

• SLO - Single Loop Operation

• GDC - General Design Criteria

• SRP - Standard Review Plan

• hr - hour

• SRV - Safety Relief Valve

• HX - Heat Exchanger

• TIP - Traversing Incore Probe

• Hz - Hertz

• UFSAR - Updated Safety Analysis Report

• IER - INPO Event Report Browns Ferry EPU License Amendment Request l 36

BFN EPU - Questions/Comments Browns Ferry EPU License Amendment Request l 37