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Ill] BFN Fire Risk Reduction and Nuclear NFPA 805 Transition

• Robert Whalen

• Keith Polson

• Joseph Shea

• Brenda Simril

• Ching Guey

• Todd Stafford

Vice President, Nuclear Engineering

Vice President, Browns Ferry Nuclear Plant

Corporate Manager, Nuclear Licensing

Senior Manager, Fire Protection

Senior Manager, PRA

Browns Ferry Fire Protection Program Owner

2

[i!lil BFN Fire Risk Reduction and Nuclear NFPA 805 Transition

• Objectives:

• Describe TVA Fleet Strategy for Fire Risk Reduction

• Review BFN Fire Protection Program Background

• Discuss Completed and Ongoing Fire Risk Reduction Modifications

• Discuss the Status of NFPA 805 Transition Project Including:

• Major Project Elements, Challenges and Milestones

• Submittal Schedule

3

TVA Fleet Fire Risk Reduction

Nuclear Strategy

• Fleetwide Strategy

- Reduce reliance on operator manual actions (OMAs)

in fire safe shutdown procedures

- Resolve Multiple Spurious Operation (MSO) issues

- Improve fire protection system material condition

• Additional Site Specific Strategies

- BFN: Implement NFPA 805 Transition

- SQN and WBN: Develop Fire PRAs

4

TVA Fleet Fire Risk Reduction

Nuclear Strategy - Browns Ferry Detail • Upgrade Fire Safe Shutdown Analysis

Reduce number of Operator Manual Actions - Eliminate high risk Self-Induced Station Blackout (SISBO) strategy - Shift from "single success path" strategy

• Modify the plant and procedures in parallel with development of NFPA 805 analysis and application

Achieve significant reduction in fire risk earlier in near term Identify and implement near term or "pull forward" activities Example: Reanalysis of turbine building and intake pumping station safe shutdown strategies and implementation of interim 551 revisions

• Drive the project to an aggressive schedule

5

BFN Fire Protection ProgramIl! BackgroundNuclear

• Plant design and construction influenced historical approach to Appendix R compliance

- Shared electrical system

- Safe shutdown analysis was based on minimal systems and components

• Resultant safe shutdown analysis utilized operator manual actions (OMAs) in lieu of cable separation

- Originally "'1400 time critical OMAs in 40 SSls

6

BFN Fire Protection Program~ Background - (Continued)Nuclear

• Safe shutdown analysis was developed to guarantee limited set of systems and components assuming a loss of offsite power (LOOP) occurred

- Self Induced Station Blackout (SISBO) Strategy

• Analysis did not consider Multiple Spurious Operations (MSOs)

7

Nuclear

Risk Reduction Plant and Procedure

Modifications

Operator Manual Action Reduction Efforts:

• TVA prioritized reduction of OMAs in parallel to developing NFPA 805 transition plan

• OMA resolution strategies included:

- Performing analysis changes for Time Critical OMAs

- Implementing feasible near term modifications

8

Risk Reduction Plant and Procedure U!il ModificationsNuclear

Operator Manual Actions Changes Achieved to Date:

• Eliminated 1V36 actions to open shop breaker at Battery Board 3 - Breaker made spare and required by procedure to remain open

for Appendix R purposes

• Eliminated 1V70 actions to start Unit 3 Diesel auxiliary transformer fans - Analysis changed to credit automatic fans start

• Revised 1V740 HVAC restoration actions from 60 min or 120 min to 4 hours based upon new room heatup analyses - Actions involve securing non-credited HVAC train and placing

credited HVAC train in service

9

Risk Reduction Plant and Procedure[i!] ModificationsNuclear

Reduction of Time-Critical OMAs «60 Minutes): - Note: Slight upward curve due to additional OMAs to mitigate Common Accident Signal

logic issues (LER 50-259-2005-005)

1600 1400 1200 1000 800 600 400 200

o

'"

" " " -----­~

I I I

Time Criticallll.G.2 OMAs

I

- Time Criticallll.G.2 OMAs

Mar-09 Sep-09 Sep-l0 11-Sep

10

Risk Reduction Plant Modifications and Procedure RevisionsNuclear

Risk Reduction Modifications:

• Installation of Incipient Detection in 250V Reactor Motor Operated Valve (RMOV) Board lA

- High Risk Ignition Source in Significance Determination Process (SOP)

- Status: Complete

• Provided covers for cable trays to increase time to damage

Installed solid bottom or top tray covers above Electrical Board Rooms for all 3 units, totaling ~100 ft of cable tray

High Risk Areas in SOP

- Status: Complete

1

Risk Reduction Plant and Procedure ModificationsNuclear

Risk Reduction Modifications (Continued):

• Turbine Building and Intake Fire area Separation

- Subdivided large fire area into 4 smaller fire areas

- New 3 hour fire barrier

- New fire safe shutdown strategy and procedures

- Status: Complete

• Installation of protective fusing for Shutdown Board 3EC

- Eliminates high risk OMA in SDP

- Status: Spring 2012 Unit 3 Refueling Outage

12

Risk Reduction Plant and Procedure ModificationsNuclear

Turbine Building Fire Area Separation - Additional Detail:

• New 3 Hour Barrier installed

- Separates Common Turbine Building from Intake Structure and Cable Tunnel

• Revised Associated Safe Shutdown Analysis and SSls

Used new shutdown strategies planned for NFPA 805 transition

Eliminated SISBO actions

Subdivided into 4 new fire areas

Reduced time critical OMAs for fires in Turbine Building/Intake Area as shown in table below

Previous 881s Revised 881s

Procedure 88125-1 88125-11 88125-1 88125-2 88125-3 88126

Time 22 25 8 3 3 3 critical OMAs

13

Pull Forward Projects Risk Reduction

TURBINE 00 00

BUILDING 00 FUEL OIL

G 0 ELEV 565 'w'ATER

HAT CH TANKS £

EACTDR BUILDING

L [GFND

. '.l KOS[ STATIm

MJLTJ -PURPOSE DRY Al PORTABLE

INTAKE PUMP STATION

~ 'IRE [lOOR

INTAKE STRUCTURE CABLE TUNNEL

BFN Fire Protection Risk Reduct ion and NFPA 80S Transition Status

12/06/2011 14

1m Risk Reduction Plant and Procedure Nuclear Modifications

Turbine Building Fire Area Separation:

....,--­ .,

New 3-hr rated fire barrier separating TB from Intake Pumping Station Tunnel

15

Risk Reduction Plant and Procedure

ModificationsNuclear

Safe Shutdown Instruction (SSI)Branching Step Revision:

• Implemented procedure changes to all 40 551s to provide alternate pathway options

- Entry conditions remained unchanged

- Operator allowed to use alternate paths IF the original 551 path cannot be executed as written (such as due to component fault)

- Procedure revisions also included warnings for major systems/trains to avoid using for a fire on one unit which could adversely impact the other units

- 5tatus: Complete (April, 2011)

16

Extrapolated SDP Risk for Risk-Reduction Measures

Nuclear (Trend Illustration Only)

Extrapolated SDP Risk for Various Risk-Reduction Measures 2.s0E-Os

.... til 2.00E-Os Qj

> .... Qj Cl. u. LsOE-Os0 u .::.:. II)

li: "C LOOE-OS Qj +' til

E ';' II)

LLJ s.00E-06

O.OOE+OO

-+-Extrapolated SDP Risk for Unit 1

~Extrapolated SDP Risk for Unit 2

-I-Extrapolated SDP Risk for Unit 3

Pull-Incipient Provide *551

Forward *551divisional RevisionSDP Fire

As BranchingDetection (AugOriginal tray

Currently Step (Q2 SDB protection 2011, FAValue

Scoped 2011)(Q12011) (Q12011) 25,26)

(Oct 2010)

2.29E-Os L8sE-Os L67E-Os L26E-Os 6.30E-06 s.68E-06

2.13E-Os L8sE-Os L70E-Os 1.38E-Os 6.88E-06 6.49E-06

1.66E-Os L3sE-Os 1.33E-Os L12E-Os s .s8E-06 s.lsE-06

SDB

protective I NFPA 80S fusing

(U3, Q2 Based 551

2012)

s.68E-06

6.49E-06

2.90E-06

LOOE-06

LOOE-06

LOOE-06

* Assume 50% reduction of the SDP risk based on SSI revision which provides guidance on use of EOI and alternate flow path

17

[ml NFPA 805 Transition Project Status Nuclear

Project Organization Overview

• TVA Corporate engineering leadership role

- PRA and fire protection group greatly strengthened

• Benchmarked industry for lessons learned to determine most effective project organization

• Four separate contract firms selected based on specialized skills and knowledge of the NFPA 805 transition process

• Detailed resourced and logic tied schedule in place to manage the project

• Project has full resource support from TVA leadership 18

~ NFPA 805 Transition Project Status Nuclear

Major Project Elements • Upgrade of Fire Safe Shutdown Analysis

- Inclusion of 11 additional systems - "'1,600 components in Appendix R - "'2,750 components for NFPA 805 - Inclusion of Offsite Power - New shutdown strategies to utilize the additional systems

• Circuit Analysis and Cable Routing for Additional SSA and PRA Components - '" 5,550 cables in Appendix R - '" 11,150 cables in NFPA 805

• Revised SAFE Model for Separation Analysis '" 13,000 cable- equipment logic relationships in Appendix R

- '" 29,000 cable- equipment logic relationships in NFPA 805

19

U!il NFPA 805 Transition Project Status Nuclear

Major Project Elements (Continued) • Upgrade PRA to model plant response to fire damage

• Modeling of Fire Scenarios

- "'3,000 fire scenarios

- Plant walkdowns to identify target cables

• Fi re Area Assessments

Establish shutdown method and credited train

Determine Variances from Deterministic Requirements (VFDRs)

"'40 Fire Areas

• Fire Risk Evaluations

20

Nuclear NFPA 805 Transition Project Status

Project Challenges • Identification of Target Cables in Plant

- Extensive plant walkdown of Fire Zones of Influence (ZOls)

• Initial Fire PRA Quantification - Process requires multiple iterations

• Multiple Spurious Operations scope was much larger than originally anticipated, requiring further analysis and documentation

21

NFPA 805 Transition Project Status II!D Nuclear

Major Project Milestones:

• Upgrade Safe Shutdown Analysis

- Status: rv 80% complete

• Circuit Analysis and Cable Routing

- Status: >90% complete

• Upgrade SAFE Database Model

- Status: >90% complete

• Fire PRA Peer Review / Completion of Fire PRA tasks

- In Progress - As discussed on Subsequent Slides

22

NFPA 805 Transition Project Status Nuclear

Major Project Milestones (cont):

• NSCA Fire Area Assessments

- In Progress

• Fire Risk Evaluations (FREs) for variances from deterministic requirements (VFDRs) identified in Fire Area Assessments

Industry standard is to perform this effort in series after completion of NSCA Fire Area Assessments

TVA has developed a staggered approach to support aggressive project schedule

• LAR preparation and submittal

23

NFPA 805 Transition Project Status U!il Nuclear

Fire PRA Peer Review/Completion of Fire PRA Tasks

• Recent assessment by ANS Fire Peer Review Standard Chair

- Assessment was element of project plan

- Outcome was decision to move the fire PRA Peer Review from week of October 24, 2011 to week of January 23, 2012

• PRA quantification is in progress and on target for peer review

• TVA team is participating in BWROG peer reviews and workshops to incorporate best practices from pilot plants and

other NFPA 805 plants

• TVA PRA Group is evaluating EPRI new fire PRA methods

- TVA understands that NRC approval would be required prior to crediting these methods

24

~ NFPA 805 Transition Project Status Nuclear

• TVA is on track for January 2012 Fire PRA Peer Review - Fire PRA Available for Potential Stand Alone Submittal - March 2012

• TVA is committed to strategy of parallel plant modification and NFPA 805 application development - Have identified additional plant modifications based on evolving Fire

PRA

• TVA updated projected schedule for submittal of complete NFPA 805 License Amendment Submittal - First Quarter CY 2013

25

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