NUREG/CP-0194

Volume 3 of 3

EPRI 1020621

Final Report

Methods for A4pplying Risk

Analysis to Fire Scenarios

(MARIA FIRES) -2008

NRC-RES/EPRI Fire Workshop

Volume 3

Module 3: Fire Analysis

Based on the Joint

NRC-RES/EPRI Training Workshops

Conducted in 2008

September 28 - October 2, 2008, and

November 17-20, 2008, Bethesda, MD

David Stroup

Felix Gonzalez

Hugh Woods

U.S. Nuclear Regulatory Commission

Office of Nuclear Regulatory Research

Washington, DC 20555-0001

Electric Power Research Institute

3420 Hillview Avenue

Palo Alto, CA 94303
AVAILABILITY OF REFERENCE MATERIALS

IN NRC PUBLICATIONS

NRC Reference Material

As of November 1999, you may electronically access

NUREG-series publications and other NRC records at

NRC's Public Electronic Reading Room at

http://www.nrc.gov/readinQ-rm.htrnl.. Publicly released

records include, to name a few, NUREG-series

publications; Federal Register notices; applicant,

licensee, and vendor documents and correspondence;

NRC correspondence and internal memoranda;

bulletins and information notices; inspection and

investigative reports; licensee event reports; and

Commission papers and their attachments.

NRC publications in the NUREG series, NRC

regulations, and Title 10, Energy, in the Code of

Federal Regulations may also be purchased from one

of these two sources. 1. The Superintendent of Documents

U.S. Government Printing Office

Mail Stop SSOP

Washington, DC 20402-0001

Internet: bookstore.gpo.gov

Telephone: 202-512-1800

Fax: 202-512-2250

2. The National Technical Information Service

Springfield, VA 22161-0002

www.ntis.gov

1-800-553-6847 or, locally, 703-605-6000

A single copy of each NRC draft report for comment is

available free, to the extent of supply, upon written

request as follows:

Address: U.S. Nuclear Regulatory Commission

Office of Administration

Mail, Distribution and Messenger Team

Washington, DC 20555-0001

E-mail: DISTRIBUTION@nrc.gov

Facsimile: 301-415-2289

Some publications in the NUREG series that are

posted at NRC's Web site address

http:/!www.nrc.qov/readinq-rm/doc-collections/nuregs

are updated periodically and may differ from the last

printed version. Although references to material found

on a Web site bear the date the material was accessed,

the material available on the date cited may

subsequently be removed from the site.

Non-NRC Reference Material

Documents available from public and special technical

libraries include all open literature items, such as

books, journal articles, and transactions, Federal

Register notices, Federal and State legislation, and

congressional reports. Such documents as theses,

dissertations, foreign reports and translations, and

non-NRC conference proceedings may be purchased

from their sponsoring organization.

Copies of industry codes and standards used in a

substantive manner in the NRC regulatory process are

maintained atThe NRC Technical Library

Two White Flint North

11545 Rockville Pike

Rockville, MD 20852-2738

These standards are available in the library for

reference use by the public. Codes and standards are

usually copyrighted and may be purchased from the

originating organization or, if they are American

National Standards, fromAmerican National Standards Institute

11 West 42nd Street

New York, NY 10036-8002

www.ansi.org

212-642-4900

Legally binding regulatory requirements are stated

only in laws; NRC regulations; licenses, including

technical specifications; or orders, not in

NUREG-series publications. The views expressed

in contractor-prepared publications in this series are

not necessarily those of the NRC.

The NUREG series comprises (1) technical and

administrative reports and books prepared by the

staff (NUREG-XXXX) or agency contractors

(NUREG/CR-XXXX), (2) proceedings of

conferences (NUREG/CP-XXXX), (3) reports

resulting from international agreements

(NUREG/IA-XXXX), (4) brochures

(NUREG/BR-XXXX), and (5) compilations of legal

decisions and orders of the Commission and Atomic

and Safety Licensing Boards and of Directors'

decisions under Section 2.206 of NRC's regulations

(NUREG-0750).

DISCLAIMER: Where the papers in these proceedings have been authored by contractors of the U. S. Government, neither the

U.S. Government nor any agency thereof, nor any U.S. employee makes any warranty, expressed or implied, or assumes any

legal liability or responsibility for any third party's use or the results of such use, of any information, apparatus, product, or

process disclosed in these proceedings, or represents that its use by such third party would not infringe privately owned rights.

The views expressed in these proceedings are not necessarily those of the U. S. Regulatory Commission.
Methods for Applying Risk Analysis to

Fire Scenarios (MARIAFIRES)-2008

NRC-RES/EPRI Fire PRA Workshop

Volume 3 - Module 3: Fire Analysis

NUREG/CP-0194 EPRI 1020621

Final Report

July 2010

U.S. Nuclear Regulatory Commission

Office of Nuclear Regulatory Research (RES)

Washington, DC 20555-0001

U.S. NRC-RES Project Manager

M. H. Salley

Electric Power Research Institute (EPRI)

3420 Hillview Avenue

Palo Alto, CA 94303

EPRI Project Manager

R. P. Kassawara
COURSE TRAINING INSTRUCTORS AND PROJECT MANAGERS

Sandia National Laboratories (SNL)

1515 Eubank SE

Albuquerque, NM 87185

Steven Nowlen

Mardy Kazarians (Kazarians & Associates)

Frank Wyant

Jeff LaChance

Science Applications International Corp. (SAIC)

1671 Dell Ave, Suite 100

Campbell, CA 95008

Bijan Najafi

Francisco Joglar-Biloch

Dan Funk (EDAN Engineering)

Richard Anoba (Anoba Consulting Services)

J.S. Hyslop/ Kendra Hill

U.S. NRC-RES Project Managers

CITATIONS

This report was prepared by:

R.P. Kassawara

EPRI Project Manager

U.S. Nuclear Regulatory Commission,

Office of Nuclear Regulatory Research (RES)

Washington, DC 20555-0001

Electric Power Research Institute (EPRI)

3420 Hillview Avenue

Palo Alto, CA 94303

Principal Investigators:

D. Stroup

F. Gonzales

Principal Investigator:

R. Kassawara

This report describes research sponsored jointly by the U.S. Nuclear Regulatory Commission,

RES, and EPRI.

The report is a corporate document that should be cited in the literature in the following manner:

Methods for Applying Risk Analysis to Fire Scenarios (MARIAFIRES), NRC-RES/EPRI Fire

PRA Workshop, Volume 3 -Module 3: Fire Analysis, U.S. Nuclear Regulatory Commission,

Office of Nuclear Regulatory Research (RES), Washington, DC 20555-0001, and Electric Power

Research Institute (EPRI), Palo Alto, CA, NUREG/CP-0194 and EPRI 1020621.

NUREG/CP-0194 and EPRI 1020621, Volume 3,

has been reproduced from the best available copy

ii
DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITIES

THIS DOCUMENT WAS PREPARED BY THE ORGANIZATION(S) NAMED BELOW AS AN

ACCOUNT OF WORK SPONSORED OR COSPONSORED BY THE ELECTRIC POWER RESEARCH

INSTITUTE, INC. (EPRI). NEITHER EPRI NOR ANY MEMBER OF EPRI, ANY COSPONSOR, THE

ORGANIZATION(S) BELOW, OR ANY PERSON ACTING ON BEHALF OF ANY OF THEM:

(A) MAKES ANY WARRANTY OR REPRESENTATION WHATSOEVER, EXPRESS OR IMPLIED,

(I) WITH RESPECT TO THE USE OF ANY INFORMATION, APPARATUS, METHOD, PROCESS, OR

SIMILAR ITEM DISCLOSED IN THIS DOCUMENT, INCLUDING MERCHANTABILITY AND FITNESS

FOR A PARTICULAR PURPOSE, OR (11) THAT SUCH USE DOES NOT INFRINGE ON OR

INTERFERE WITH PRIVATELY OWNED RIGHTS, INCLUDING ANY PARTY'S INTELLECTUAL

PROPERTY, OR (111) THAT THIS DOCUMENT IS SUITABLE TO ANY PARTICULAR USER'S

CIRCUMSTANCE; OR

(B) ASSUMES RESPONSIBILITY FOR ANY DAMAGES OR OTHER LIABILITY WHATSOEVER

(INCLUDING ANY CONSEQUENTIAL DAMAGES, EVEN IF EPRI OR ANY EPRI REPRESENTATIVE

HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES) RESULTING FROM YOUR

SELECTION OR USE OF THIS DOCUMENT OR ANY INFORMATION, APPARATUS, METHOD,

PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS DOCUMENT.

ORGANIZATION THAT PREPARED THIS DOCUMENT:

U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research

NOTE

For further information about EPRI, call the EPRI Customer Assistance Center at

800.313.3774 or

e-mail askepritepri.com.

Electric Power Research Institute, EPRI, and TOGETHER ... SHAPING THE FUTURE OF ELECTRICITY

are registered service marks of the Electric Power Research Institute, Inc.

ABSTRACT

The U.S. Nuclear Regulatory Commission (NRC) approved the risk-informed and

performance-based alternative regulation 10 CFR 50.48(c) in July 2004, which allows licensees

the option of using fire protection requirements contained in the National Fire Protection

Association (NFPA) Standard 805, "Performance Based Standard for Fire Protection for LightWater Reactor Electric Generating Plants, 2001 Edition," with certain exceptions. To support

licensees's use of that option, NRC and the Electric Power Research Institute (EPRI) jointly

issued NUREG/CR-6850 (EPRI 1011989) "Fire PRA Methodology for Nuclear Power

Facilities," in September 2005. That report documents the state-of-the art methods, tools, and

data for conducting a fire probabilistic risk assessment (PRA) in a commercial nuclear power

plant (NPP) application. The report is intended to serve the needs of a fire risk analysis team by

providing a general framework for conduct of the overall analysis as well as specific

recommended practices to address each key aspect of the analysis. Participants from the U.S.

nuclear power industry supported demonstration analyses and provided peer review of the

program. Methodological issues raised in past fire risk analyses, including the Individual Plant

Examination of External Events fire analyses, are addressed to the extent allowed by the current

state-of-the-art and the overall project scope. Although the primary objective of the report is to

consolidate existing state-of-the-art methods, in many areas, the newly documented methods

represent a significant advance over previous methods.

NUREG/CR-6850 does not constitute regulatory requirements, and NRC participation in

this study neither constitutes nor implies regulatory approval of applications based on the

analysis contained in this document. The analyses/methods documented in this report represent

the combined efforts of individuals from RES and EPRI. Both organizations provided specialists

in the use of fire PRA to support this work. The results from this combined effort do not

constitute either a regulatory position or regulatory guidance.

In addition, NUREG/CR-6850 can be used for risk-informed, performance-based

approaches and insights to support fire protection regulatory decision-making in general.

On 14-16 June 2005, NRC's Office of Nuclear Regulatory Research (RES) and EPRI

conducted a joint public workshop for about 80 attendees at the EPRI NDE Center in Charlotte,

NC. A second workshop was held the following year, on 24-26 May 2006, in NRC's Two White

Flint North Auditorium in Rockville, MD. About 130 people attended the second workshop.

Based on the positive public response to these two workshops, a more detailed training class was

developed by the authors of NUREG/CR-6850. Two detailed training workshops were

conducted in 2007: on 23-27 July and again on 27-30 August, both at EPRI in Palo Alto, CA.

About 100 people attended each of these workshops. In 2008, two more workshops were held

from 29 September through 2 October, and again from 17-20 November in Bethesda, MD, near

NRC Headquarters. The two workshops attracted about 170 participants including domestic

representatives from NRC Headquarters and all four regional offices, U.S. Department of

Energy, National Aeronautics and Space Administration, EPRI, NPP licensees/utilities, Nuclear

Steam Supply System vendors, consulting engineering firms, and universities. Also in

iii
attendance were international representatives from Belgium, Canada, France, Japan, South

Korea, Spain, and Sweden.

The material in this NUREG/CP was recorded at the workshops in 2008 and adapted by

RES Fire Research Branch members for use as an alternative training method for those who were

unable to physically attend the training sessions. This report can also serve as a refresher for

those who attended one or more training sessions and would be useful preparatory material for

those planning to attend a session.

NRC Disclaimer: This document's text and video content are intended solely for use as training

tools. No portions of their content are intended to represent NRC conclusions or Regulatory

Positions, and they should not be interpreted as such.

iv
CONTENTS OF VOLUME 3

A B S T R A C T ...... ......................................... ........................................................ iii

ACKNOW LEDGEMENTS ...................................................................................... vii

LIST OF ACRONYMS ......................................................................................... ix

I INTRODUCTION - FIRE ANALYSIS OVERVIEW ........................................................... 1-1

1.1 EPRI Perspective ......................................................................................................... 1-1

2 FIRE ANALYSIS SLIDES ..................................................................................................... 2-1

Session la: Plant Partitioning .............................................................................................. 2-1

Session 1b: Example Problems ......................................................................................... 2-14

Session 2a: Fire Ignition Frequency .................................................................................. 2-19

Session 2b: Example Problems ........................................................................................ 2-48

Session 3: Scoping Fire Modeling ..................................................................................... 2-65

Session 4: Heat Release Rate .......................................................................................... 2-83

Session 5: Fire Severity .................................................................................................... 2-97

Session 6a: Damage Criteria ........................................................................................... 2-108

Session 6b: Example Problems ...................................................................................... 2-119

Session 7: Detailed Fire Modeling and Single Compartment Fire Scenarios ................... 2-130

Session 8: Detection and Suppression ........................................................................... 2-148

Session 9: Special Fire Models Part 1 ............................................................................. 2-164

Session 10a: Special Fire Models Part 2 ......................................................................... 2-192

Session 10b: Example Problems ..................................................................................... 2-201

Session 11 a: Main Control Room Fire Analysis ............................................................... 2-215

Session 11 b: Example Problems ..................................................................................... 2-234

Session 12: Multi-Compartment Fire Analysis ................................................................ 2-249

Session 13: Seismic Fire Interaction ............................................................................... 2-259

CONCLUSION ......................................................................................................................... 3-1

P a rt 1 : In te g ra tio n ................................................................................................................ 3 -1

Part 2: Lessons Learned and Insights ................................................................................. 3-6

Part 3: Perspective ............................................................................................................ 3-20

V
CONTENTS OF VOLUME 3 (CONTINUED)

A PPENDIC ES ................................................................................................... A-1

Appendix A: Questions Asked in Module 3 Sessions ........................... A-1

Appendix B: Reference Tables and Figures ................................................................... B-1

Appendix C: Exercise Set Solutions ............................................................................... C -1

Session ib: Example Problems (Plant Partitioning) ........................... C -1

Session 2b: Example Problems (Fire Ignition Frequency) ...................... 0 -6

Session 6b: Example Problems (Scoping Fire Modeling) .............................................. C-19

Session 10b: Example Problems (Detailed Fire Modeling) ............................................. C-31

Session 11 b: Example Problems (Main Control Room Fire Analysis) ............................. C-53

vi
Acknowledgements

The authors of this report greatly appreciate the efforts and contributions made by Carli Follett, David

Yates, and Thomas DeBold, summer interns from the University of Maryland's Fire Protection

Engineering Department, during development of this NUREG/Conference Proceedings report. As part of

their summer internship, they were tasked to analyze, evaluate, organize, and edit information in the

videos of this report and to develop its first draft under direct supervision of the authors. They compiled

all the video files and presentation materials used during the training sessions and used their knowledge to

create, organize, edit, and deliver a user-friendly report of the highest quality possible.

We also acknowledge the other Fire Research Branch members Kendra Hill, Aixa Belen-Ojeda, Jason

Dreisbach, Jessica Kratchman, Gabriel Taylor, J.S. Hyslop, and Mark Henry Salley for their support and

contributions during its development. Their input and encouragement facilitated its timely completion

and greatly benefited the final product.

In addition, we want to extend our gratitude to Nathan White and Thomas Kardaras of the Information

Technology and Infrastructure Branch for their quick responses addressing all our computer needs and

issues during development of the report. We greatly appreciate the support of Linda Stevenson (the

agency publication specialist) and Guy Beltz (the agency printing specialist) whose invaluable support

and expertise were critical to ensuring the published report's quality.

Also, several other 2009 Office of Nuclear Regulatory Research summer interns, specifically Minh Dang,

Daniel Breedlove, Ashley Carnes, and Anders Gilbertson, made valuable contributions to this project,

both technical and editorial, that contributed to its overall quality.

vii

LIST OF ACRONYMS

ACB

ACRS

AEP

AFW

AGS

AOP

AOV

ATHEANA

ATS

ATWS

BAT

BNL

BWR

CBDT

CCDP

CF

CCPS

CCW

CDF

CFD

CFR

CLERP

CM

CR

CRS

CST

CVCS

CWP

DC

EDG

EDS

EF

El

EOP

EPR

EPRI

Air-cooled Circuit Breaker

Advisory Committee on Reactor Safeguards

Abnormal Event Procedure

Auxiliary Feedwater

Assistance General Supervisor

Abnormal Operating Procedure

Air Operated Valve

A Technique for Human Event Analysis

Automatic Transfer Switch

Anticipated Transient Without Scram

Boric Acid Tank

Brookhaven National Laboratory

Boiling-Water Reactor

Causal Based Decision Tree

Conditional Core Damage Probability

Cable (Configuration) Factors

Center for Chemical Process Safety

Component Cooling Water

Core Damage Frequency

Computational Fluid Dynamics

Code of Federal Regulations

Conditional Large Early Release Probability

Corrective Maintenance

Control Room

Cable and Raceway (Database) System

Condensate Storage Tank

Chemical and Volume Control System

Circulating Water Pump

Direct Current

Emergency Diesel Generator

Electrical Distribution System

Error Factor

Erroneous Status Indicator

Emergency Operating Procedure

Ethylene-Propylene Rubber

Electric Power Research Institute

ix
FEDB Fire Events Database

FEP Fire Emergency Procedure

FHA Fire Hazards Analysis

FIVE Fire-Induced Vulnerability Evaluation (EPRI TR 100370)

FMRC Factory Mutual Research Corporation

FPRAIG Fire PRA Implementation Guide (EPRI TR 105928)

FRSS Fire Risk Scoping Study (NUREG/CR-5088)

FSAR Final Safety Analysis Report

HEAF High Energy Arcing Fault

HEP Human Error Probability

HFE Human Failure Event

HPI High-Pressure Injection

HPCI High-Pressure Coolant Injection

HRA Human Reliability Analysis

HRR Heat Release Rate

HTGR High Temperature Gas-cooled Reactor

HVAC Heating, Ventilation, and Air Conditioning

ICDP Incremental Core Damage Probability

ILERP Incremental Large Early Release Probability

INPO Institute for Nuclear Power Operations

IPE Individual Plant Examination

IPEEE Individual Plant Examination of External Events

IS Ignition Source

ISLOCA Interfacing Systems Loss of Coolant Accident

KS Key Switch

LCO Limiting Condition of Operation

LERF Large Early Release Frequency

LFL Lower Flammability Limit

LOC Loss of Control

LOCA Loss-of-Coolant Accident

LPG Liquefied Petroleum Gas

LWGR Light-Water-cooled Graphite Reactors (Russian design)

MCB Main Control Board

MCC Motor Control Center

MCR Main Control Room

MG Motor-Generator

MFW Main Feedwater

MOV Motor-Operated Valve

MQH McCaffrey, Quintiere and Harkleroad's Method

MS Main Steam

MSIV Main Steam Isolation Valve

NC No Consequence

NEI Nuclear Energy Institute

NEIL Nuclear Electric Insurance Limited

NFPA National Fire Protection Association

NPP Nuclear Power Plant

X
NPSH Net Positive Suction Head

NQ cable Non-Qualified (IEEE-383) cable

NRC U.S. Nuclear Regulatory Commission

P&ID Piping and Instrumentation Diagram

PE Polyethylene

PM Preventive Maintenance

PMMA Polymethyl Methacrylate

PORV Power-Operated Relief Valve

PRA Probabilistic Risk Assessment

PSF Performance Shaping Factor

PTS Pressurized Thermal Shock

PVC Polyvinyl Chloride

PWR Pressurized-Water Reactor

Q cable Qualified (IEEE-383) cable

RBMK Reactor Bolshoy Moshchnosty Kanalny (high-power channel reactor)

RCIC Reactor Core Isolation Cooling

RCP Reactor Coolant Pump

RCS Reactor Coolant System

RDAT Computer program for Bayesian analysis

RES Office of Nuclear Regulatory Research (at NRC)

RHR Residual Heat Removal

RI/PB Risk-Informed / Performance-Based

RPS Reactor Protection System

RWST Refueling Water Storage Tank

SCBA Self-Contained Breathing Apparatus

SDP Significance Determination Process

SGTR Steam Generator Tube Rupture

SI Safety Injection

SMA Seismic Margin Assessment

SNPP Simplified Nuclear Power Plant

SO Spurious Operation

SOV Solenoid Operated Valve

SRV Safety Relief Valve

SSD Safe Shutdown

SSEL Safe Shutdown Equipment List

SST Station Service Transformer

SUT Start-up Transformer

SW Service Water

SWGR Switchgear

T/G Turbine/Generator

THERP Technique for Human Error Rate Prediction

TGB Turbine-Generator Building

TSP Transfer Switch Panel

UAT Unit Auxiliary Transformer

VCT Volume Control Tank

VTT Valtion Teknillinen Tutkimuskeskus (Technical Research Centre of Finland)

xi
VVER The Soviet (and now, Russian Federation) designation for light-water

pressurized reactor

XLPE Cross-Linked Polyethylene

ZOI Zone of Influence

xii
1 INTRODUCTION - FIRE ANALYSIS OVERVIEW

Within the context of a nuclear power plant (NPP), fires present a special hazard because fire can damage

multiple equipment intended to mitigate core damage. This determination of fire damage is made through

fire modeling using simple empirical approaches to complex, computer codes such as CFAST or FDS.

NUREG/CR-6850 provides the framework for including fire models in fire probabilistic risk assessment

(PRA) and describes simple empirical models to assess fire damage. Extensive information on the more

complex approaches such as CFAST and FDS is referred to NUREG-1824, the verification and validation

of several fire models.

Cables are important fire damage targets in fire PRA models. Simple empirical models to evaluate cable

damage, including damage to cables in different trays, are included in the methods presented. Thresholds

for cable damage, primarily to thermoset and thermoplastic cables, are also discussed. Besides simple

empirical models, more complex rule sets to evaluate high-energy arcing faults are also presented in this

part of the training.

The treatment of heat-release rates has been expanded in NUREG/CR-6850, and distributions of heatrelease rates for many types of fire sources have been provided. For example, heat-release rates for

electrical cabinets depend on the configuration of cables in the cabinet and the cabinet itself. In addition,

the severity factor concept, which refers to that portion of the heat-release rate above which damage

occurs, has been improved.

Besides explicit fire modeling, the "Fire" portion of this training describes how fire-suppression activities

are treated and evaluated. Fire suppression includes prompt suppression, such as for'hot work, and

automatic and manual fire suppression. Fire damage is generally evaluated in fire PRA under success and

failure of fire suppression.

This module also describes how to divide the plant into regions to be used for analysis. A fire

compartment is a common region applied in fire PRA. Fires producing damage across regions are also

considered. Moreover, guidance on counting components and transferring those counts to fire frequency

is provided. Guidance for a qualitative assessment of seismic-fire interactions is included.

1.1 EPRI Perspective

"Methods for Applying Risk Analysis to Fire Scenarios (MARLAFIRES)" is a collection of the materials

that are presented at the fire PRA course provided by the Electric Power Research Institute (EPRI) and

the U.S. Nuclear Regulatory Commission's (NRC's) Office of Nuclear Regulatory Research (RES). The

training and resulting presentation material is detailed and represents in excess of 60 hours of classroom

instruction. The training focuses on the fire PRA methods documented in the joint EPRI/RES publication

1011989 and NUREG/CR-6850 along with clarifications, enhancements, and additions provided via the

Frequently Asked Question (FAQ) process for NFPA 805.

The intent of the publication is to provide to the public the training material used at the fire PRA training.

This material is not intended to be a substitute for direct interaction that is provided in the periodically

offered fire PRA courses; rather, it is meant to augment that training and to serve as a reference.

Enthusiastic future students can use the material to become familiar with the general principles of fire

PRA prior to arrival at the course. Students who have already taken the course can use the material for

1-1
reference. The material consists of a series of reports that document the presentations including some

speakers' notes and text. In addition, an edited version of a recorded training session is also available via

a separate product number. This video version can be used in a similar manner to the documentation

(e.g., for reference or in preparation for the course) and includes the actual recorded and edited course.

This material is being provided With the hope that those who plan to attend the course can arrive more

informed, those who have already attended can have a reference, and those who have been unable to

attend can have a resource to gain a more complete understanding of the intent and goals of EPRI

1011989 and NUJREG/CR-6850.

1-2
2 FIRE ANALYSIS SLIDES

Session la: Plant Partitioning

2-1
Slide 1 Notes:

U. S.' N R C

SWb r1lborw

RECTRI C O

EPRIINRC-RES FIRE PRA

METHODOLOGY

Task 1: Plant Partitioning

- Joint RES/EPRI Fire PRA Workshop

September, 2008

Washington, DC

Aibotion of U.S. NRC Ofrceof Nucletr Regulatory Research (RES) & Electric Power Research Institute (EPRI)

Slide 2 Notes:

P Scope lant Partitioning

The following topics are covered:

- Task 1: Plant Partitioning Analysis

- Define Global Analysis Boundary

- Partition into physical analysis units or Compartments

- Problem sets from the Sample Problem

W' d°oy WA ° t°O, (IS. NRC1O: °0f Ndnt Rft 

Task I: Ptant Pahtl~onltngReahiRS& IdiPw R nhItueERI

2-2
Slide 3 Notes:

Support Task A: Plant Walkdowns

Just a Quick Note....

* You cannot complete a Fire PRA without walkdowns

* Expect to conduct a number of walkdowns, especially for

key areas (e.g., those analyzed in detail)

* Walkdowns can have many objectives and support many

tasks:

- Partitioning features, equipment/cable mapping, fire ignition

source counting, fire scenario definitions, fire modeling, detection

and suppression features, recovery actions HRA

* Walkdowns are generally a team activity so coordinate

them to optimize personnel time and resources

FPr P54 worA M"W • 200a WfhlntmO A [ý AO OflcwSNAOfie W Rg y TS. fpIP0 .,AAOrAng R0,h ASS) & AehA#A PowerAS, Mrh ,.Iug (PPA4

Slide 4 Notes:

Plant General Partitioning CommentlObservation

The recommended practice for Task 1 has changed little

from prior methods.

- That means you can likely benefit from a previous analysis

e.g., your IPEEE fire analysis

However: watch out for new equipment/cables, new initiators when

screening

PAm P5A Workshop, 2208, Washingfm DCNcAS C l A oAlab ai US SNC Office RgatArY

Task 1: PI-an PAAAIAA ReA, (ASS &E fIt Power Ae.e5hInCARut (EPRA)

2-3
Slide 5 Notes:

! Task 1: Plant Partitioning Key Definitions: Compartment vs. Fire Area/Zone

We talk mainly about Fire Compartments which are defined

in the context of the Fire PRA only

- Defining Fire Compartments is necessary for analysis management

- Also known as Physical Analysis Units

* Fire Areas are defined in the context of your regulatory

compliance fire protection program

* Fire Zones are generally defined in the context of fire

protection features (e.g., detection, suppression, hazards)

- Fire zones have no direct meaning to the Fire PRA context and we

avoid using this term

• Physical Analysis Unit is another term coined lately

Fus PRA Wo*.SP. 2008. WM. sh0l• M S Rewnrh C* (RES° S" NR r O Nuc 0020 R°

Task 1: Pntalt P80twnllg l Res (RES) & Eý ý Rea I e (EPRO

Slide 6 Notes:

! Task 1: Plant Partitioning Task Objectives and Output

There are two main objectives to Task 1:

1. Define the Global Analysis Boundary

* The maximum physical extent of the plant that will be considered in the

Fire PRA

2. Divide the areas within the Global Analysis Boundary into analysis

Compartments (Physical Analysis Units)

* The basic physical units that will be analyzed and for which risk results

will be reported

Task output is the definition of these two aspects of the

analysis

Firm PR Workso,5 . 2006. Washington Dc C A C30oa o d US NRC 00f2Of NeRegu atoý3y

Trsk I: P-a Ph a,oooning R h (-) & 003,00 030- e (00PR

2-4
Slide 7 Notes:

Task Task Input 1: Plant Partitioning

* No real input from any other task is required (it is, after all,

Task 1)

- There is a link to the equipment and cable selection Tasks 2 and 3

- You may also find yourself iterating back to this task later in the

analysis - that is fine, just be careful to track any changes

* What do you need to support this Task?

- Layout drawings that identify major structures, walls, openings

. Drawings that identify Fire Areas are especially helpful

- Plan and elevation drawings are helpful

- You will need to do a walkdown to support/verify decisions

Fire PRA Workshop, 2008, W.SIVl-gtOl Sk 7 W dt oebeo. et U.S, NRC OffiAe o4 NU08-. 08504,yW

Task 1: FUet ParMInSMg ft , (WDS) dtPtil08 rei IAlitfl F-PRO

Slide 8 Notes:

! Task 1: Plant Partitioning Task Breakdown in Steps

Task 1 is defined in terms of the following steps:

Step 1: Selection of Global Plant Analysis Boundary

Step 2: Plant Partitioning

Step 3: Compartment Information Gathering and Characterization

Step 4: Documentation

Fme PRA Workm*op, 2008. W irngtfon Sl d A Coieorelre. U.S SOC S dO k 0011107

TsO 1: Plbnt PafOhlonlng 0ar*h ISS S FkIt P RtSh SOufe COPR

2-5
Slide 9 Notes:

Task 1: Plant Partitioning

Selection of Global Plant Analysis Boundary

We want a Liberal definition of the global analysis

boundary

- It's OK to include obviously unimportant areas, we'll drop them

quickly, but better to do this formally

* Encompass all areas of the plant associated with both

normal and emergency reactor operating and support

systems, as well as power production

* Sister Units should be included unless they are physically

and functionally separated

- No shared areas, no shared systems, no shared components and

associated cables, no conjoined areas (e.g., shared walls)

Fe PRA Po ,ra W. 2008, Wmhtgton C A CoonoUS NRC 0Mm dNucRP~guAar.y

Task 1: Pnff ftrtonlV RnwiacIZ (RiO) Z=Ectrc =or -=nEtM (FF0

Slide 10 Notes:

Task 1: Plant Partitioning Selection of Global Plant Analysis Boundary (2)

* Begin with your protected area: everything within the

protected area should be included in the Global Analysis

Boundary

- In most cases that will capture all risk-important locations

* If necessary, expand the boundary to include any other

locations that house equipment or cables identified in

Tasks 2 or 3

- This is the Task 2/3 link mentioned before!

- Example: If your offsite power related equipment is outside the

protected area, you need to expand Global Analysis Boundary to

capture it

Fim PRA WOraFhF. 2008, Wasmgton DC I s1t t O A C] abor olS. NRC Offim N/ati RýguJtey Task 1: Ptlnt Prltitioning R.5..r¢h (RES) & Firerri Pa... Resrb0 Th~tituA (EPRI)

2-6
Slide 11 Notes:

Task Selection 1: Plant of Global Partitioning Plant Analysis Boundary (3)

* Problem Set 01-01

* By the end of the analysis, you need to provide a fire risk

disposition for all locations within the global analysis

boundary

- That may be anything from screened out qualitatively to a detailed

risk quantification result

Fm_ PRA W___, 200a DC _hgn A -ok 6 U&S. NýRC OfflWN- RIWol

Task : Pb.r rfltftrnlng F I (ýS) I .... X-0

Slide 12 Notes:

Task 1: Plant Partitioning

Plant Partitioning into Fire Compartments (1)

* We divide the Global Analysis Boundary into smaller

pieces (compartments) for the purpose of tracking and

reporting risk results

* A compartment can be many things, but when it comes

down to it, a compartment is:

A well-defined volume within the plant ... that is

expected to substantially contain the adverse effects of

fires within the compartment.

Ts1 PinPt W 08P0, waefon g. Cc S (AREdS,& E6 CS.eNR 

0

- -9,RrCh I PR

Task 1: M- nt Paffoning Rws-rc (RES) & Ebskdd 0, - lna~ - -d (EPRI)

2-7
Slide 13 Notes:

r Task Plant Partitioning 1: Plant Partitioning into Fire Compartments (2)

* This task is often subjective -judgment is required

* Ideally: Compartments = Rooms

- Locations that are fully defined by physical partitioning features

such as walls, floors, and ceilings

* But the ideal is not the only solution - other features and

elements may be credited in partitioning

- That's where judgment comes into play!

- What will you credit as a Partitioning Feature?

Fke PRA WoMpO , 2008, WslMnMon DC C (R ES &Nn7 f Pl . -0, (EUI R#

TRk 1: plant PM ontng Rerch (RdES) A U-t* w e U. (EPRO

Slide 14 Notes:

g Task 1: Plant Partitioning Plant Partitioning into Fire Compartments (3)

* A good starting point is your Fire Areas, but you are by no

means limited to equating Fire Compartments to Fire Areas

- A Fire Area may be partitioned to two or more Compartments

- You may combine two or more Fire Areas into a single

Compartment

* In the end: { I Compartments } = { Global Analysis Bnd. }

- No omissions

- No overlap!

F-e PRA Worsop, 2008, WOaeington C 'DC 7 RM50 R o & S . R , St n (EPR O

Task 1: Plant Part(Ioning R.- (RES) & Et P R .. M (ER#

2-8
Task 1: Plant Par

Plant Partitioning in

So what can you cre

- Bottom line: anything

You do need to just

elements maintaine

- In the end, your parti

results, but..

- Don't go crazy - ther

- General guideline: try

multi-compartment sc

Re PPA ýWop. 2M58, Wýkn DC

T*M : M,1 Pfl5On

Slide 15 Notes:

titioning

to Fire Compartments (4)

dit as a partitioning feature:

you can justify - see text for examples

ify your decisions with the exception of structural

d as rated fire barriers

tioning decisions should not affect the risk

e are disadvantages to over-partitioning

y to minimize the need to develop and analyze

cenarios

A Cý -a~oa• U, S, . R ed u aa

SRli deS & 080 (ERR Notes: 

Slide 16 Notes:

! Task Plant Partitioning 1: Plant Partitioning into Fire Compartments (6)

There are some things that you should not credit in

partitioning:

- Partial height walls

- Radiant energy shields

- Beam pockets

- Equipment obstructions (e.g., pipes)

- (ANS Standard says: Raceway or other localized fire barriers may

notbe credited in partitioning)

Problem Set 01-02

F"e PRA Worshlop, 2008, M0W02, 0 DC • A C -bratinoOU.S. NRC OR °f5uO1iSM(aY

Tk 1: PkantPrtitoning R---,h (RES) . -COR - -R 00ch -- In-00te (ERR)

2-9
Slide 17 Notes:

Task Plant Partitioning 1: Plant Partitioning into Fire Compartments (7)

Final Point: You need a system to identify/name your Fire

Compartments

- Something both consistent and logical - but whatever works for

your application and plant

- Often makes sense to use Fire Area designations in naming

schemes

. Example: Fire Area 42 might become Fire Compartments 42A, 42B...

- Use your naming scheme consistently throughout the Fire PRA

* Documentation, equipment/cable tracing, database, etc.

Fse PRA Wor*shop, 2008, WashingtC DC S61 a ceoe of U.S CRC 0f c ONU R.ty

Task 1: Punt peat fosnl g Re--h (RES) & ecrisc P -oerReMeh ,,sfufe (EPRi)

Slide 18 Notes:

! Task 1: Plant Partitioning Compartment Information Gathering and... (1)

Later tasks need certain information about each

compartment. They include, but are not limited to the

following:

- Compartment boundary characteristics

- Ventilation features, and connections

- Fire protection features

- Fire source hazards

- Identification of all adjacent compartments

- Identification of components/systems/cables

- Access routes to the fire compartment

- SSD human actions credited in each compartment

Fire PRA Worksho, 2008, Washingtow O C AS;;1 Co8] A os oa US NRC Ole oN RPAs•y

-.& f: p-*n Ps -,Eoiehg Re-eh (-ES) . Flet Poer - R-ee.h - u.- (-0 ,

2-10
Slide 19 Notes:

Task 1: Plant Partitioning Compartment Information Gathering and... (1)

* A thorough plant walkdown is needed to confirm and

gather information about each fire compartment.

* Initially it is not expected that all information pieces to be

collected and documented.

- As work on fire PRA progresses, additional information, as

needed, is collected and documented

- This task, similar to other later tasks, is expected to be

*revisited and compartment definitions modified as

additional information is obtained.

Ff- PRA WVr*Mp. 200$, fthgUon 0C [j 1;c_=9 A U-1 NRC 0d000w ghy

m'aWd( f: Pbant Parpnwlongnh R~a~ftýh (RES) & Sf0 Ro n rn hnflf l- (EPR0

2-11
Slide 20

! Task 1: Plant Partitioning Compartment Information Gathering and... (2)

ire Compartment ID #

ire Compartment Switchgear Access Room

uilding uxiliary Building

Buandary Characteristics The compartment is bounded by 3-hr rated fire walls, ceiling and floor.

entilation Features The ventilation is provided by the Auxiliary Building HVAC system"'i. The

eqquipment housed in this compartment can function properly and perform their

safe shutdown duties in case of total loss of the HVAC system.

ire Protection Features nhe fire protection features of this compartment includes:

1. Handheld extinguishers inside the compartment (2 units)1•'

.Wet hose reel outside the door inside the stairwellm 1

3 Smoke detectors attached to the ceiling (6 units)`"

Fire Sources The following ignition sources were identified in this compartment,

1. MCC-A

Z MCC-B

3.125VAC-A

4. 125VAC-B

5. ATS

6. Lighting Fixtures (10 units)(1')

Additionally the following combustibles are present:

1. Cable trays containing thermoset control cables

. Wooden desk used by the electrical department")

dijacent Compartments The following compartments share a wall, ceiling or floor with this compartment:

1. Switchgear Room A

2* Switchgear Room B

3 Stairwell

. Charging pump room

5. Cable spreading room

Access Routes 1. This room can be accessed from outside through the stairwell

2 Sw.tchyeat Rooms A and B are accessed through this room

=omponents/ystems/Cables See the component and cable lists provided in Tasks 2 and 3. Present

SS Human Actions Credited To be completed after Task 12 is completed.

in this Compartment I

(1) Provided here to demonstrate how this part of the step may be addressed. These features are not intended to

be included in the fire PRA of this example plant,

Fire PRA Workshop, 2008, Washington DC

Task 1: Plant Partitioning

.. l.. 20 . A Collaboration of U.S. NRC Office of Nuclear Regulatory

. S .. Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-12
Slide 21 Notes:

! Task Summary 1: Plant Partitioning

* Plant Partitioning is the first step of fire PRA.

Done in three steps

1. Define global plant analysis boundaries to include all those area that will be addressed by the fire PRA

2. Define fire compartments in such a way that all the areas

identified in the preceding step are covered, there are no overlaps

and there is a balance between size and number of compartments

selected

3. Confirm the selected compartments through a walkdown and

record important information that will be used later.

r- PRA W'o.rRop, 2MOR, bRMIn OC L A C~o~bqkd of U S NRC C2=0 Wf N 0lotR y

Tnsk 1: PMant PMrronlng R0e0h (REU) & EltrA ,R° AC h osiRe f (:55S

2-13
Session 1b: Example Problems

2-14
Workshop Problems for Task 1: Plant Boundary Definition and Partitioning

Workshop Problem Set 01-01

Step I - Selection of Global Plant Analysis Boundary: Using Drawing # 01 in the Sample

Package and the information provided in other drawings, identify the Global Plant Analysis

Boundaries in terms of plant areas. Make a complete list of plant areas shown on Drawing #01

in the matrix provided below. Specify whether or not the area shall be included within the

Global Plant Analysis Boundaries and then provide the basis of your decision.

Plant Area Included? Basis

4 .4

4 .4

2-15
Plant Area Included? Basis

________ 4

2-16
Workshop Problem Set 01-02

Step 2: Plant Partitioning: Using the drawings provided in the Sample Package, identify the set

of fire compartments that you will consider for the fire PRA. In the following matrix (1) list

selected compartments, (2) give each an identification number, (3) identify the associated plant

area for each compartment from the Solution Statement for Problem Set 01-01. Provide

comments where warranted.

Fire Comp. Fire Compartment Plant Area Comments

ID # Descriptor

+ 4 +

2-17
Fire Comp. Fire Compartment Plant Area Comments

ID # Descriptor

2-18
Session 2a: Fire Ignition Frequency

2-19
Slide 1 Notes:

CU.S.NRC

nit Mi

R=~~IEECIRIC MOWR c-a ERHER.C INTtMfE

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Task 6: Fire Ignition Frequency

Joint RES/EPRI Fire PRA Workshop

September, 2008

Washington DC

I A Collabortio, of U.S. NRC Office of Nulear Regulatory Research (RES)& Electric Pow,, Research Institute (EPRIJ

Slide 2 Notes:

! FIRE IGNITION FREQUENCIES Purpose of Task 6

In Task 6, the ignition frequencies associated with fire ignition sources are established.

- Generic frequencies

- Plant specific experience

- Uncertainties

To be presented in two parts:

* 1. How to estimate location specific frequencies

* 2. How generic frequencies were put together

Fire PRA Fire Worksop, 200M, Washnglon DC A CAo-Mkabo•: NRC OfH0d N SU ucwledRe to

Task 6: Fre gnition FIqueny R,.och RES} £010000 Po R -o -rh1n6, (EPRq

2-20
Slide 3 Notes:

FIRE IGNITION FREQUENCIES Assumptions

The model developed for estimating fire ignition frequencies

is based on the following assumptions:

- Frequencies remain constant over time

- Total ignition frequency for an equipment type is the same for all

plants

- Within each plant, ignition frequency is the same for all equipment of

the same type.

Rh' PRA Wo,1nws% 2008, ýMton DC W A C -' us.anaflU.& NRC OfM, &c NUw Ra•,°a

atM 6: FhvWh. lataFn~ rcy -...r (-S) * 0*1, -o,,as0 -St 1(00

Slide 4 Notes:

g FIRE General IGNITION ApproachFREQUENCIES

To establish the fire frequency of a fire compartment, the

ignition frequencies associated with each ignition source of

the compartment are added together.

- AJL = 7- AIsWLWSJL

summed over all ignition sources

Where:

AJL : Fire frequency associated with compartment J at location L

Als: Plant level fire ignition frequency associated with ignition

source IS

WL: Location weighting factor

WISJ.L: Ignition source weighting factor

Fire PRA Wokshop, 2000, Wasington DC ACdsatorat U Sof0 NRC OR/coWf w• Rsgaty

Task. 6, Fe Ignitio Fnqu y Rý R -h (REES) & 80 - , e.arch - ,aJluf. (I8EpR

2-21
Slide 5 Notes:

! FIRE IGNITION FREQUENCIES Plant Level Frequency (Aks)

Plant level fire ignition frequency covers all the equipment of

the same type in the entire unit.

Examples:

- 2.1 E-02 is the frequency per year of fires within a unit that involve

pumps.

- 7.4E-03 is the frequency per year of transient fires within the turbine

building of a unit.

Fit* PR4 Wot4shoP. 2008, Washington DC i A Co niioS UUS. nd4 O ofNctec Rqgulahoy

Thsh 6: FPr. Ifgnon •t..y Rh a . hESE h Es h W .P'E- b) 0 Ins.- (-P0I)

2-22
Slide 6

FIRE IGNITION FREQUENCIES

Plant Level Frequencies (Als)

Table 6 -1

Fire Frequency Bins and Generic Frequencies

Generic Split Fractions for Fire Type

•ID Location Ignition Source Mode Freq I (Equipment Type) (per rx yr) Electrical Oil Transient Hotwork Hydrogen HEAF_

1 Battery Room Batteries All 7.5E-04 1.0 0 0 0 0 0 .

2 Containment (PWR) Reactor Coolant Pump PowerI 6.1E-03 0.14 0.86 0 0 0 0

4 Control Room Main Control Board All 2.5E-03 1.0 0 0 0 0

8 Diesel Generator

Room A Pel Generators All 2.1 E-02 0.16 0.84 0 0 0 0

11 LPlant-Wide I Cable fires caused by Power 2.OE-03 0 0 0 1.0 0 0

Ignition Frequency Bi 4.6E-03 1.0 0 0 0 0

Components

1t Plant-Wide Electrical Cabinets All 4.5E-02 1.0 0 0 0 0 0

Components

20 Plant-Wide Off-gas/H2 Recombiner Power 4.4E-02 0 0 0 0 1.0 0

Components (BWR)

27 Transformer Yard Transformer - Catastrophic2 Power 6.OE-03 1.0 0 0 0 0

32 Turbine Building Main Feedwater Pumps Power 1.3E-02 0.11 0.89 0 0 0 0

2. S:: Soriun' 65.01060, b.-or .dfnitiun

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency Side....... . A Collaboration of U.S. NRC Office of Nuclear Regulatory i ................................... 6 R Research aSlide (RES) & Electric Power Research Institute (EPRI)

Notes:

2-23
Slide 7

FIRE IGNITION FREQUENCIES

Plant Level Frequencies (A s)

T

Ire Frequency Bins and Ge 'c Frequencies

,#ýr rqLoycatinon G 1n Ignition Sou Equipment TI

Generic

rpe) (per rx yr)

.p..' ra.-n .... .. -r. yp

Electricall Oil Transient Hotwork I Hydrogenl HEAF'

,,,J-l. -i - i-I. I- I--I ± ____

0 0 %0..Lattery Room__..aoo~fatteries All I 7.5E-04 1 1.0 0 0 0 0 0

2 Containment (PR) Reactor Coolant Pump Power 6.1E-03 0.14 0.86 .0 1 0 0

4 Control Room Main Control Board Allf 2.5E-03 1.0 0 1 10 :0 O

________4-L L-4 0 4 4-

8

11 P

C

14 P

C

15 P

C

20 P

C

3241T

.See Se

mini i -16 0.841 0 0 0 0

ID Location

1 Battery Room

2 Containment (PWR)

4 Control Room

8 Diesel Generator Room

0 0 0 1.0 .0 0

.0 0 0 0 0 0

.0 0 0 0 0 0

0 0 0 0 1.0 0

.0 0 0 0 0

11 0.89 0 0 0 0

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency

.Slide7 .. A Collaboration of U.S. NRC Office of Nuclear Regulatory I. . Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-24
Slide 8

I FIRE IGNITION FREQUENCIES

Plant Level Frequencies (Als)

Table 6 -1

Generic Split Fractions for Fire Type cation Ignition Source M Freq ID Lo (Equipment Type) e (per ro yr) Electrical Oil Transient Hotwork Hydrogen HEAF'

1 Battery Room ris-All 7.5E-04 1.0 0 0 0 0 0

2 Containment (PWR) Reactor Coolan ump Power 6.1E-03 0.14 0.86 0 0 0 0 X

4 Control Rn ha C n nt; l B I n n n n n n

8 Diesel Gt

Room

11 Piant-Wic ID Location Ignition Source

ComponE (Equipment Type)

14 Plant-Wid

Compon 1 Battery Room Batteries 15 Plant-W ic

ComponE 2 Containment (PWR) Reactor Coolant Pumps

20 Plant-Wic

compon 4 Control Room Main Control Boards

27. Transfor

8 Diesel Generator Room Diesel Generators 32 Turbine B

1. S" Appendi. I

2. See OSecio 6.5.6 balom for a efinition.

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency Side..... . A Collaboration of U.S. NRC Office of Nuclear Regulatory .Slide8 .. Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-25
Slide 9

FIRE IGNITION FREQUENCIES

Plant Level Frequencies (A1s)

Table 6 -1

r.- Frequency Bins and G I"

ID , Location Ignition Source

(Equipment Type)

I Generic Split Fractions for Fire Type

Mode Freq HEAF pore r yr) EiectricailTransienotwork ydrogen .EAF'1_> 1 2Containment Bltery Room (PWR) Reactor att er i7.5--04 Coolant Pump Power 1R1.0 1o0 1a0 0 16.1IE-0 0O. 14 10.861 0 0 0 0j1

I I J I I J J I I I I

m - r -R Anl 1 i95 .p- I TM I I n I n I n I n

Generic Split Fractions for Fire Type Ignition SourceFreq

(Equipment Type) (per rx yr) Electrical Oil Transient Hotwork Hydrogen HEAF 1

Batteries All 7.5E-04 1.0 0 0 0 0 0

Reactor Coolant Pump Power 6.1E-03 0.14 0.86 0 0 0 0

Transients and Hotwork Power 2.OE-03 0 0 0.44 0.56 0 0

Main Control Board All 2.5E-03 1.0 0 0 0 0 0

i ,- iunrnn• ll mann i ln =mn ~ PowT~ werl 1 771-I 12 u []ll 89 [] II u [] u

i•=1 I ....... I . . . . I .. . . I . . . I .. . I I I i I 1. See Appendix M for a descnption of high-energy arcing fault (HEAF) fires.

2. See Section 6.5.6 ,elm for a definition.

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency

Sd I A Collaboration of U.S. NRC Office of Nuclear Regulatory lid........ Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-26
FIRE IGNITION FR

Location Weighting F

Location weighting fact

for those cases where E

units of the same plant.

- All frequencies were de

- Examples: Turbine Bul

- Example: WL = 2.0 if th

units

Fk P • Won*F. nA 2M, l*ngl0 DC

moo 6: Fk 1900X0, Flq -ly

Slide 10 Notes:

EQUENCIES

actor (WL)

or adjusts the plant level frequencies common location is shared among

eveloped per unit basis

Iding, Auxiliary Building, Control Room

e Turbine Building is shared between two

7, A;W boato ol U E nR Wfký ofý R.04.

e (RES) 11 N sPRO

Slide 11 Notes:

FIRE IGNITION FREQUENCIES

Ignition Source Weighting Factor (WsjL)

Ignition source weighting factor is the fraction of an ignition source type found in a specific compartment.

- Need to count all the items belonging to one ignition source type in

one unit

Necessitates a thorough plant walk-down and review of engineering

documents

- Example: if there are two battery rooms in one unit, each housing

one battery set, WIS,J.L = 0.5

- Transients and cables are based on specific models

Fkv PRA Wo,00000, 2008, Wa4000o DC [111 A CDO,0ooo 08 N.C O00 Nu00 R4oV

T.sk 6: FPi Inio.n FPu.•-y R -0r,0 (RES) & E R.arh 00.u (EPRO

2-27
Slide 12 Notes:

FIRE IGNITION FREQUENCIES Procedure

The following procedure can be used to estimate location

specific fire ignition frequencies:

* Step 1. Mapping plant ignition sources to generic sources,

* Step 2. Plant fire event data collection and review,

* Step 3. Plant specific updates of generic ignition

frequencies,

* Step 4. Mapping plant-specific locations to generic locations,

* Step 5. Location weighting factors,

* Step 6. Fixed fire ignition source counts,

* Step 7. Ignition source weighting factors, and

* Step 8. Ignition source and compartment fire frequency

evaluation.

W ' O 1 5;•' n F S ?DC A Cowonfr.,& °VNRC 5?ce °N a.t Rqiy

T 6: F&Rm Igitio, Fr y R (RES) & E•C • . - (EýR#

Slide 13 Notes:

FIRE IGNITION FREQUENCIES Step 1. Mapping Plant Ignition Sources

Every plant equipment item should be mapped to one of the

ignition frequency bins.

- Must be capable of initiating a fire

- Must be located in the buildings, compartments and plant areas

considered for fire risk analysis

- If no matching bin, then the following approach may be used:

- Characteristics of the source

- Percentage of the time in operation

- Past fire histories within the plant

- Relevant past fire histories or frequency estimates not associated

with the plant

Problem Set 06-01

FM,? PPR4 WokUOp, 2008, t sh n D3 Sl A Cd• a U.S NRCOf &,?NN . RbR týoy

Task 6: Fm Igniion Fmqnncy Rfe- (RES) & EictE -oRs sE -h (EpRR)

2-28
FIRE IGNITION FR

Step 2. Plant Fire Eve

Plant specific fire event

specific fire ignition freq

- Are plant specific fire ig

* Repeated set of event

* Events that cannot be

- Unusual fire occurrenc

- May be selective in pla

Ff. PP4 wot*shw, Xp 8, wa00flto DC

TaW 6," Fi IgnR10on Frequency

Slide 14 Notes:

EQUENCIES

nt Data Collection

data is needed to establish plant

luencies.

gnition frequencies warranted?

mapped to a bin

e patterns

nt specific frequencies

RS d (RES)15 &N(

Slide 15 Notes:

! FIRE IGNITION FREQUENCIES Step 2. Plant Fire Event... (2)

Example:

- The following events have taken place:

* Event 1: Fire in MCC-A because of breakers not properly engaging the

bus bars.

* Event 2: Fire in 125VAC-A panel. The fire was extinguished when 4kV

bus-A was de-energized from the control room. Fire resulted from arcing

of supply lead to one of the fittings connecting to a controller to the bus.

- Both fires can be included in the frequency analysis.

- Plant has been in commercial operation for 10 years.

- Both events should be mapped to Bin # 15 "Electrical Cabinets"

- 2/10 = 0.2, is 4 time greater than 0.045, Bin #15 frequency

Problem Sets 06-02 and 06-03 (Examples)

Fire PRA Wo,•shop, 2008, Washiton DC A Co-Ow & VUS. NRC Os-fýeN Rgu

Task 5. Fire Ignition Freque y R.- (Re) & - s-h u (P)

2-29
Slide 16 Notes:

FIRE IGNITION FREQUENCIES Step 3. Plant Specific Frequencies (A1s)

Bayesian approach can be used to estimate plant specific fire

ignition frequencies.

- Uncertainty distributions of generic frequencies as the prior

- Possible double accounting of FEDB events

Fk. FAA WýO,ý* 2008. Dc A Co#80oO &of 0 S. NRC Offkl N& - R010 Y

T. 6: Fft lgldft FqnY S Rea (RES) & E-dft o e fR, ftl - (EMORI

2-30
Slide 17

UFIRE IGNITION FREQUENCIES

Steps 4/5. Plant-Specific Locations and WL

Plant specific locations should be mapped to the bin .definition

locations.

Example:

Plant Specific Bin Location WL

Location

Emergency Battery Battery Room Number of site units that

Enclosure share common set of

batteries.

Main Control Room Control Room Number of site units that

share the same control

room.

Control Building Control I Auxiliary I Number of site units that

Primary Auxiliary Reactor Building share the same building

Building type.

- Problem Sets 06-04 and 06-05

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-31
Slide 18 Notes:

! FIRE Step 6. IGNITION Fixed Fire FREQUENCIES Ignition Source Counts

To establish ignition source weighting factor, Wlsu, for each

compartment, it is necessary to obtain the total number of

relevant items per bin.

- For shared tocations, entire site should be considered

- Visual examination (recommended approach)

- Document review or computerized database

- Counting method for each bin

Fiue PtAW W*k 2 Washingto 00 8 A CtboratnaU.S NRC OffceadNuCleRgstaV

Task 6: Fkt fgtnlýor Fsýsf y Rk.S., (RES) & ElýCtn* Pit-ower h POlkA. (EPRI)

Slide 19 Notes:

FIRE IGNITION FREQUENCIES

Step 6. (cont'd)

Examples:

" Bin ]- Batteries. Each bank of interconnected sets of batteries

located in one place should be counted as one battery set.

Cellsmay not be counted individually.

" Bin 5- Cable Fires Caused by Welding and Cutting:....

Assume that all exposed cables (i.e., cables that are not in

conduits or wrapped by noncombustible materials) have an

equal likelihood of experiencing a fire caused by welding and

cutting across the entire location....

" Bin 14- Electric Cabinets: Electrical cabinets represent..

switchgears, motor control centers, DC distribution panels,

relay cabinets .... Free standing electrical cabinets should be

counted by their vertical segments,...

Fir PRA Workshop, 2000, Washington DC sca s oO

Task 6: 5)10 IgntonPq cRy .s-h (RES) & E- P- R-Sorch 100•fufe (EPRI)

2-32
Slide 20

FIRE IGNITION FREQUENCIES

Step 6. Related FAQs

- FAQ 06-0016 - Ignition source counting guidance for electrical cabinets.

(Status: Closed)

Cabinet is not an outlier -

Count = 1

Cabinet is same as standard -

Count = 1

Internal dividers are not solid -

Count = 6

Internal dividers are solid -

Count = 6

Slide . 20 A Collaboration of U.S. NRC Office of Nuclear Regulatory ..... S -ie 0 Research (RES) & Electric Power Research Institute (EPRI)

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency

Notes:

2-33
Slide 21

I FIRE IGNITION FREQUENCIES

Step 6. Related FAQs (cont'd)

FAQ 06-0016 - Continued.

Three independent cabinets -

Count = 3

Panel is an outlier, using a 4'

standard cabinet -

Count = 3

Cabinet is an outlier, no evaluation of

contents, based on reference cabinet -

Count = 3 due to variation from the

standard length and depth

The counts should depend on the

cable termination load and devices

in the panel by comparing it with a

reference cabinet.

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency 1 A Collaboration of U.S. NRC Office of Nuclear Regulatory i e...................................... j Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-34
Slide 22 Notes:

! FIRE Step 6. IGNITION Related FAQs FREQUENCIES (cont'd)

FAQ 06-0017 - Ignition source counting guidance for high

energy arcing faults. (Status: Closed)

- Split Bin # 16 into:

* Bin 16a - Low-voltage panels (480 to 1,000 V) - 4.8E-04/ry (mean)

* Bin 16b - medium-voltage panels (> 1,000V) - 1.4E-03/ry (mean)

- Counting method remains unchanged (i.e., vertical sections)

- Self consistent within each new bins

FAQ 06-0018 - Ignition source counting guidance for main

control board. (Status: Closed)

- There is a one-to-one correspondence between App. L and Bin 4.

- Main Control Board is just the horseshoe.

- All other electrical cabinets in the Main Control Room should be

counted with other cabinets in the plant.

Fk. PP.A Wo•. ý2. W r;;;;- ;-- a A C2Mntab °s" NRC OffFdý NdU& RnutýtY

T.8kg; Fin Ignikon Fnqmr-y L....... (nnw Ios V *,cn.. ý yf' - (-)8

Slide 23 Notes:

I FIRE IGNITION FREQUENCIES Step 6. Related FAQs (cont'd)

FAQ 06-0031: Ignition source counting guidance

clarifications and extensions (Status: Closed)

- Bin 14 - Electric motors: clarifies guidance, provides for excluding

small motors of 5hp or less and totally enclosed motors.

- Bin 21 - Pumps: provides for excluding small sampling pumps, and

other pumps of 5hp or less

- Bin 23 - Transformers: provides for excluding dry transformers of

45KVA or less

- Bin 26 - Ventilation subsystems: clarifies that intent is to exclude

small subsystems powered by motors of 5hp or less (consistent with

electric motors bin 14)

FiRb P0 Wo0sho, 2008. Washingt• DC 23 A olab080ndof U.S. NRC Oftf Nd NW RVeg•atoay

TPek 6: Fir Igntion Frequency R-Scb0 (RES & - 000. -E(.d¢ R -Sf, -nrt (EM0()

2-35
Slide 24 Notes:

! Step FIRE 6. IGNITION Related FAQs FREQUENCIES (cont'd)

FAQ 07-0035: High energy arc faults in bus ducts (Status:

Open)

- Issue:

. Guidance document is silent on topic

- General approach to resolution: '

* Acknowledge potential for such events (e.g., Diablo Canyon 5/2000)

* Provide plant wide frequency and counting/partitioning guidance

Provide zone of influence and scenario development guidance

- Status:

* FAQ resolution has been drafted and reviewed

* Final revisions in process

F.. PRA Wo,*shw, 2002. W-•hflo, DC m A Cal U. NC OM 0N00080

T.. 6: Fin Ignition Frequency --- Re (ySS C 6l.5* pon, Re~t. *r80. (EF00

Slide 25 Notes:

FIRE IGNITION FREQUENCIES Step 6. Related FAQs (cont'd)

FAQ 08-0042: Cabinet Fire Propagation (Status: Open)

- Issue:

* Guidance provides conflicting language regarding propagation of fire from cabinets (Chapter 6 versus Appendix G) and definition of "well-sealed

cabinets)

* Implication for Step 6: you exclude well-sealed cabinets from cabinet

count if contents are below 440V (see Vol. 2, Page 6-17)

- General approach to resolution:

Clarify and expand definition of "well-sealed and robustly secured

cabinets" (which will not propagate fires)

- Status:

* FAQ resolution has been drafted and reviewed by RES/EPRI team

* Industry and NRC staff reviews pending

FpRA W.rks2P28, W8, h6gto DC A CoflbC.I., SI S NR00Offn dS.uC.rRnahiw

T.k 6: FiM Ignikon Fnwucy R,.&00 (S) & 01 F, Power e 08tu (EPRO

2-36
Slide 26 Notes:

FIRE IGNITION FREQUENCIES Step 6. Related FAQs (cont'd)

FAQ 08-0048 Fire Frequency Trends (Status: Open)

- Issue:

* Fire frequency analysis may not reflect industry trends (i.e., towards

reduced fire frequencies)

- General approach to resolution:

* Work is under way within EPRI team to determine if statistically significant

fire frequency trends can be demonstrated

* Fire frequencies for one or more ignition source bins may be modified (up

or down depending on trends)

- Status:

* Work to date remains largely within the EPRI team

* Review/input by RES team pending

Fb, pRA Worhp 2, WaDD. - D 2 A CoUab,,CS, oUS. NRC 0D'G oNkdruo

Task 6: Fim IgniUon Frequeny R I-nh (RES) & El-t20 p. Re d (FO(00 -h o 

Slide 27 Notes:

FIRE IGNITION FREQUENCIES Step 7. Ignition Source Weighting Factor (WIs,J,L)

Ignition source weighting factors are evaluated for all the

compartments identified in Task 1 and for all ignition sources identified in Step 1 of this Task.

- Countable items

Example: 2 pumps in compartment J of 50 pumps in the unit

Wbs,j,L =2/50 = 0.04

- Transients - apportioned based on maintenance, occupancy and

storage

- Large systems - ad-hoc method based on specific characteristics of

the system

. Examples: hydrogen gas distribution system, turbine/generator oil system

* Problem Sets 06-08, 06-09 and 06-10

FmR PRA WoOS&Op, 2000, WhgI DC = A CO~auS NCOffiReuoy

TLM 9: Fir gnl Fe n(R•) & E)00l O(tr .,RI08*(0O 00..u (E0R4

2-37
Slide 28 Notes:

FIRE IGNITION FREQUENCIES Step 7. WIS,J,L-- Transients

Transient fire frequencies are apportioned based on

qualitatively estimated rating levels for (1) maintenance

activities, (2) occupancy level and traffic density and (3)

storage (temporary and permanent) of combustible and

flammable materials.

- Five rating levels are used:

* No (0) - Can be used only for those compartments where transients are

precluded by design (administrative restrictions do not apply).

* Low (1)-Reflects minimal level of the factor.

* Medium (3)-Reflects average level of the factor.

* High (10)-Reflects the higher-than-average level of the factor.

Very high (50)-Reflects the significantly higher-than-average level of the

factor (only for "maintenance" influencing factor).

Fkv PRA Wo*WW, 2008, Wo-wton DC S 8 A 8bo0505a U.S NRC Oftice W• .

0

l

8

0,kIo

Tak s: Fi Ignlton Fuqnncy Rý(msh (RE,'tV £ E Powe Rnnerh 8 e (EARS

2-38
Slide 29

! FIRE IGNITION FREQUENCIES Step 7. WIS,J,L- Transients (2)

Table 6-3

Description of Transient Fire Influencing Factors

Influencing No (0) Low (1) Medium (3)

Factor

Maintenance Maintenance Small number Average

activities of PM/CM number of

during power work orders PM/CM work

operation are compared to orders.

precluded by the average

design. number of

work orders

for a typical

compartment.

Occupancy Entrance to Compartment Compartment

the with low foot not

compartment traffic or out of continuously

is not possible general traffic occupied, but

during plant path. with regular

operation. foot traffic.

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency .:ý- .I A Collaboration of U.S. NRC Office of Nuclear Regulatory

............. ......... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-39
Slide 30

FIRE IGNITION FREQUENCIES

Step 7. WIS,J,L- Transients (3)

The following normalization equations are used:

- For General Transients:

WGTJL = (nm,j,L + no,JL + ns,jL/NGTL

NGTL = nm,iL + i,L + ns, id)

(summed over i, all compartments of location L)

- For Transient Fires Caused by Welding and Cutting:

WWC,JL = nm,j/Nwc

Nwc = •E n, iL

(summed over i, all the compartments of location L)

- For Cable Fires Caused by Welding and Cutting:

WCF, J =nmJ WCableJ /NcF

NcF =EnmiL 'WCablel

(summed over i, all compartments of location L)

Problem Sets 06-11

Fire PRA Workshop, 2008, Washington DC A Collaboration of U.S. NRC Office of Nuclear Regulatory

Task 6: Fire Ignition Frequency Sld .e.. 30... .. Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-40
Slide 31

FIRE IGNITION FREQUENCIES

Step 8. Fire Frequency Evaluation

The fire frequency (generic or plant-specific) for each ignition

source, A1sj, can now be calculated using the data quantified

in the preceding steps.

AJL -- AISWLWIS,J,L

summed over all ignition sources

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency

I 3 A Collaboration of U.S. NRC Office of Nuclear Regulatory

1....... 31._..... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-41
FIRE IGNITION FR

Determination of Gen

The generic fire frequen

experience of U.S. nucl

- Large uncertainties

- Two stage Bayesian ap

- EPRI Fire Event Datab

- Analysis of each event

- FAQ 08-0048 - Fire Ig

R. PRA Wo0800A 2008. Negr,, DC

mao: NP*. lntoni. Fftsy

Slide 32 Notes:

EQUENCIES

eric Fire Frequencies

ncies are based on the collective ear power industry.

pproach

ase (FEDB)

nition Frequency (in process)

520.32 A CooIOno U&,dU NRC 080t2e o09 O.N8(RKat Raaaj ioES)& Eý R-s Po• Rw chO•ft EPRIO

Slide 33 Notes:

FIRE IGNITION FREQUENCIES

Fire Event Data

EPRI's Fire Event Data Base (FEDB) was used to establish

the historical fire events for generic fire frequency estimation.

- Licensee event reports

- Industry sources (e.g., NEIL and ANI)

- Various studies

- Specific plant data

- Individual event follow-up

Fim PRO Wo,*shop, 2008, Washingfn DC s A CoSabosafon otUS NRC Offi ar Reg.tat fco t 

Task 6: Fre Ignlion FP ueanoy R n..h -. (ESS) 45E- P- R.Sah Inlbt e (ESR,)

2-42
Slide 34 Notes:

FIRE IGNITION FREQUENCIES

Event Data Analysis

For each event, information was reviewed and the following

were established:

Event Report Contents

- Occurrence date

- Plant type (i.e., PWR vs. BWR)

- Plant status (operating mode)

- Fire Location

- Fire Cause

- Initiating equipment and

combustibles

- Detection and suppression

information

- Severity related information

- Event description (narrative)

Fh. PRA 5bo*MR, 2008, W500,OlVto DC

T1.k 0: FR lglton Fr.qu.ncy

Event Analysis and Assignments

- Challenging?

- Location

- Ignition source

- Operating mode

- High energy arcing (electrical

cab.)

- Suppression data

* Prompt?

* Supp. Curve Category (e.g.

electrical)

* Duration

.147 * C .,o l S 5Hj ' S NRC ftc l Rq.*.Nry Rrn.0-8 (RE5) &500 E0.r•PowerA INO 0n5u80E

2-43
Slide 35

FIRE IGNITION FREQUENCIES Number of Events

For each plant and bin combination, the number of events

were estimated using the following eight possible event

classifications:

Table C-1

Fire Event Classifications and Frequency Estimation Action

Information Deficiencies Frequency Estimation

Class. # Action

Known Plant Known Op. Challenging Multiplier Method of

Mode Fire inclusion

1 Yes Yes Yes 1 As is

2 Yes Yes Undetermined q As is

3 Yes No Yes p As is

4 Yes No Undetermined qp As is

5 No Yes Yes 1 Distribute

among units

Distribute

6 No Yes Undetermined q amongiuts

among units

Distribute 7 No No Yes p among units

Distribute 8 No No Undetermined qp among units

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency Siude 35 A Collaboration of U.S. NRC Office of Nuclear Regulatory

....... I I. Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-44
Slide 36 Notes:

FIRE IGNITION FREQUENCIES Reactor Years

For each plant, two time periods were established - (1)

power production mode and (2) low power or shutdown mode

- Assumed 62% capacity factor prior to 1994

- NUREG-1350 data for post 1994 capacity factors

- Total reactor years since initial commercial operation

- Added the reactor years of the units for multi-unit sites

Fir. PRA Workshop, 2008, WW20.0tf. CC A 0r . NRC -0 - 0 ft.

Tlk M F1r. 1g.10- FM.u- R - (RES) & ECR010 P-r fet h oCC (EPRI)

2-45
Slide 37

FIRE IGNITION FREQUENCIES Generic Fire Ignition Frequencies

# of Total RDAT Output # Location Ignition Source Events Ev ns Reactor Years Mean Me n 5% 5509 50% 95%%

1 Battery Room Batteries 1.0 2486 7.5E-04 2.OE-05 3.2E-04 2.4E-03

2 Containment (PWR) Reactor Coolant Pump 6.5 1089 6.1E-03 3.1E-04 3.6E-03 1.7E-02

3 Containment (PWR) Transients and hotwork 2.4 1089 2.OE-03 1.3E-04 1.1E-03 5.9E-03

4 Control Room Main control board 5.5 2486 2.5E-03 8.4E-05 1.2E-03 7.3E-03

5 Control/Auxiliary/Rea Cable fires caused by 2.0 1674 1.6E-03 3.1E-05 6.4E-04 5.OE-03

ctor Building welding and cutting

6 Control/Auxiliary/Rea Transient fires caused by 12.6 1674 9.7E-03 8.9E-05 2.4E-03 3.3E-02

.ctor Building welding and cutting

7 Control/Auxiliary/Rea Transients 6.0 1674 3.9E-03 1.6E-04 2.2E-03 1.1E-02

ctor Building

8 Diesel Generator Diesel generators 49.5 2486 2.1E-02 1.9E-03 1.2E-02 6.6E-02

Room

9 Plant-Wide Air compressors 5.0 2486 2.4E-03 3.8E-05 9.OE-04 7.9E-03

Components

Fire PRA Workshop, 2008, Washington DC

Task 6: Fire Ignition Frequency 1 A Collaboration of U.S. NRC Office of Nuclear Regulatory S j Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-46
Slide 38

FIRE IGNITION FREQUENCIES

Concluding Remarks

Fire ignition frequency evaluation (Task 6) uses a mix of plant specific and generic information to establish the ignition frequencies for specific compartments and from that for

specific fire scenarios.

- Generic fire ignition frequencies based on industry experience

- Elaborate data analysis method

- Frequencies binned by equipment type

- Methodology to apportion frequencies according to relative

characteristics of each compartment

FM PRA Wo,&kshp• M M~gw ,e. DC Coyaakn 0, UAS. NRC OMfc Ne RýWgRtWy

T.k 6: Re Ignlen Fteqeny Reesýh (RSS) & Se~oc Ree h kn5l&Ee (EPR1I

Notes:

2-47
Session 2b: Example Problems

/

2-48
Workshop Problems for Task 6: Fire Ignition Frequency

Workshop Problem Set 06-01

Step 1: Mapping plant ignition sources to generic sources: Using the information provided in

this Sample Package, map the items listed in the following table to generic sources.

Equipment Equipment Description Equipment Bin # Bin Description / Comment\

ID Type

HPI-B High pressure safety injection pump B

MOV-1 HPI valve

MOV-5 RWST isolation valve

BAT-B Train B Battery

RCP-1 *Reactor coolant pump 1

AOV-1 /

(SOV-1)

SOy-i) Pilot operated relief valve

PT-1 RCS pressure transmitter

EDG-A Train A Emergency Diesel Generator

MCC-B1 Train B 480 V Motor Control Center

ATS-1 Automatic Transfer Switch Panel

VITAL-A Train A 120 VAC Vital Bus

SWGR-A Train A 4160 V Bus

LC-A Train A 480 V Load Center

SST-A Train A Station Service Transformer

BC-A Train A Battery Charger

DC BUS-A Train A 125 VDC Bus

PNL-A Train A 125 VDC Panel

INV-A Train A Inverter

AFW-A Motor driven AFW pump A

AFW-B Steam driven AFW Pump B

SUT-1 Startup Transformer

2-49
Workshop Problem Set 06-02 (Example)

Step 2: Plant Fire Event Data Collection and Review: The following tables provide examples

of fire events data collected for the sample nuclear power plant.

Fire Event # 1

Event date: January 1, 2007

Event Description: At approximately 16:49, a fire resulted from a shorf caused by the slabs on the

MCC-A breakers not properly engaging the bus bars. As a result of a short, insulation on some

wires ignited, resulting in a fire. The fire was discovered immediately by employees who

extinguished the blaze with portable fire extinguishers. Damage was confined to the cabinet where

the fire occurred, located inside the motor control center.

Should this event be considered in fire frequency calculation? Yes

Basis: The event occurred during power operation. Extent of damage was sufficient to render the

ignition source inoperable and the flames and hot gases threatened the integrity of other items

nearby.

Associated Bin ID # per Table 6-1 of Ref.1: 15

Bin Location: Plant-wide components

Bin Description:Electrical Cabinets

Basis: The fire was initiated in an MCC. An MCC is considered an electrical cabinet.

Fire Event # 2

Event date: February 1, 2007

Event Description: A fire occurred in the 120VAC-A panel. The fire was extinguished when 4kV

bus-A was de- energized from the control room. Fire resulted from arcing of supply lead to one of

the fittings connecting to a controller to the bus. Problems have been previously experienced with

this type of devices in other plants.

Should this event be considered in fire frequency calculation? Yes

Basis: The event occurred during power operation. Extent of damage was sufficient to render the

gnition source (i.e., 120VAC bus) inoperable and threaten the integrity of other items nearby.

Associated Bin ID # per Table 6-1 of Ref.1: 15

Bin Location: Plant-wide components

Bin Description:Electrical Cabinets

Basis: The fire was initiated in a 120VAC panel, which is considered as an electrical cabinet.

2-50
Workshop Problem Set 06-03 (Example)

Step 3: Plant Specific Updates of Generic Ignition Frequencies: The following bullets

provide a sample discussion of how the fire events presented in the previous sections were

treated in the Fire PRA.

* The two events identified in the preceding step are certainly significant and should be

included in a statistical analysis of fire frequency (e.g., Bayesian update of generic

frequencies.)

* Plant has been in commercial operation for 10 years.

" Both events should be mapped to Bin # 15 "Electrical Cabinets"

* The resulting frequency can be approximated by 2/10 = 0.2 per electrical cabinet year.

* The estimated frequency is 4 times greater than 0.045, Bin #15 generic frequency

" Fire PRA analysts decided not to include this plant specific experience in the fire frequency

analysis. The decision is based on the following: "The two events do not point out an

unusual trend in electrical cabinet fires. The two panels where the fires had occurred were

dissimilar items. Therefore, the plant experience is not deemed to be indicative of unusually

high electrical cabinet fire tendency at this plant."

" For all other bins, the experience is no events in 10 years (both power and shutdown) or 8

years (assuming 20% outages). If subjected to Bayesian update, the impact of this

experience on bin frequencies is minimal.

2-51
Workshop Problem Set 06-04

Step 4: Mapping Plant-Specific Locations to Generic Locations: Using the information

provided in this Sample Package, map the items listed in the following table to the applicable

generic locations provided in NUREG/CR 6850. Note that some of the compartments may map

to more than one Generic Location.

Step 5: Location Weighting Factors: Assign the location weighting factors of the Fire

Compartments in the following table.

Fire Plant Fire Compartment Plant Area Generic Location WL

Comp. # I

1

2

3

4A

4B

5

6

9

10

11

14

7

8A

8B

12

15

13

14

Main Control Room

Aux Bldg El. 0 Ft

Cable Spreading Room

RHR Pump Room

AFW Pump Room

Battery Room A

Battery Room B

SWG Access Room

Switchgear Room A

Switchgear Room B

Stairway

Containment

DG-A Room

DG-B Room

Turbine Bldg El. 0 Ft

Battery Room 1

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Auxiliary Building

Containment

DG Bldg.

DG Bldg.

Turbine Building

Turbine Building

Yard

Intake Structure

Yard

Intake Structure

2-52
Workshop Problem Set 06-05

Step 5: Location Weighting Factors: At a two-unit nuclear power plant, the Main Control Room

is shared between the two units. The control room consists of two separate Main Control Boards

that do not share any controls and are dedicated to one unit each. There are 5 electrical cabinets

in the control room in addition to the Main Control Boards that are shared between the two units.

a. For Unit 1, establish the Location Weighting Factor of the Main Control Board

b. For Unit 1, establish the Location Weighting Factor of the electrical cabinets.

c. For Unit 1, establish the Location Weighting Factor of transient fires in the Main Control Room

2-53
Workshop Problem Set 06-06

Step 6: Fixed Fire Ignition Source Counts: Estimate the ignition source counts for only those

items that are noted under each picture and are visible in the foreground of the picture:

Electrical Panels: Electrical Panels:

Transformers:

Transformers: Electrical Panels:

Transformers:

Electrical Panels: Electrical Panels:

2-54
Electrical Panels: Electrical Panels:

Electrical Panels:

(These are sealed panels with low voltage

circuits)

2-55
Workshop Problem Set 06-07

Step 6: Fixed Fire Ignition Source Counts: Estimate the ignition source counts for the components identified in Step 1 above.

Bin # and Description (per Table 6-1)

1 2 8 j 4 [ 9 110 141 15 16 121 23a 23b 29

'0

0=

o

0 C

00.

7U

0£

0

(U

0

C

0

C,

(I,

0

0

0

0

C.)

C[

0

CL

E

0

(U

0

(U

C.)

0

(U

0

T.

0

LU

C.2

(U

0U

G-.

C IL uJ

(U

0.E

IL

0=

(U

C

I0=

El-

(U

0

'0

XFMR- FMR- •FMR-

# Compartment Plant Area BAT RCP DG MCB AC BC EM EC HEAF PMP XFMR il Yrd Dry Oil Yard

1 Main Control Room Control/Aux/Reactor Building

2 Aux Bldg El. 0 Ft Control/Aux/Reactor Building

3 Cable Spreading Room Control/Aux/Reactor Building

4A RHR Pump Room Control/Aux/Reactor Building

4B AFW Pump Room Control/Aux/Reactor Building

5 Battery Room A Plant Wide Components

6 Battery Room B Plant Wide Components

9 SWG Access Room Plant Wide Components

10 Switchgear Room A Plant Wide Components

11 Switchgear Room B Plant Wide Components

14 Stairway Plant Wide Components

7 Containment Containment

8A DG-A Room Plant Wide Components

8B DG-B Room Plant Wide Components

12 Turbine Bldg El. 0 Ft Plant Wide Components

15 Battery Room 1 Plant Wide Components

13 Yard Plant Wide Components

14 Intake Structure Plant Wide Components

Total

2-56
Workshop Problem Set 06-08

Step 7: Ignition Source Weighting Factors: For an NPP, the fire PRA analysts have counted 23

pumps within the Plant Analysis Boundary.

* For RHR Pump RHRP-C located in RHR Pump room (FZ-03A), which in turn is located

in the Auxiliary Building, establish the IS, J and L subscripts of:

WIS,J,L =

" For the same RHR Pump, RIHRP-C, calculate the Ignition Source Weighting Factor

* RHR Pump room FZ-03A contains three pumps. Calculate the ignition source weighting

factor for the pumps in this compartment.

2-57
Workshop Problem Set 06-09

Step 7: Ignition Source Weighting Factors: For an NPP, the fire PRA analysts have counted

351 electrical cabinet vertical sections within the Plant Analysis Boundary.

* 480VAC MCC-A is composed of 32 breakers arranged in 8 vertical segments. Calculate

the ignition source weighting factor for this MCC.

WMCCB

* 4kV non-lE Switchgear 1 is composed of 8 breakers. Each breaker takes up one vertical

segment of the switchgear. Calculate the ignition source weighting factor for this

electrical panel.

WSWG-1 =

" The local control panel, CP-1, for the chemicals addition system located in the Reactor

Building has the following dimensions: 2' Deep, 12'Long, 8'High. There are no

partitions within the panel. Calculate the ignition source weighting factor for this

electrical panel.

Wcp_ -

2-58
Workshop Problem Set 06-10

Step 7: Ignition Source Weighting Factors: Using the information provided in the solution for Problem Set 06-07, calculate the

component weighting factors for the components listed below.

Bin # and Description (per Table 6-.1

1 1 2 18 14 19.. ...1.10 1 14.1 15• 1 16.1. 21]1 23a 2

.(.

a)

a)

C

•E

00.

C.5

(U

0

(U

a)

C

a) 0

(U

a)

0

0

m

C

0

.E

0

.U

a.

E

0o

(U

a)

a)

(U

C-,

a)

(U

U)

.)

,';

(U

a)

C

(U

C-,

C.)

U

a)

w

a)

C

a)-

"-U.

Lu

.0

"R0.

E

dm

0

(S

a)

E

0

0=

(U

I--

E(

0 4-t•

(-0

# Compartment Plant Area BAT RCP DG MCB AC BC EM EC HEAF PMP XFMR- XFMR- XFMR- Dry Oil Yard

1 Main Control Room Control/Aux/Reactor Building _

2 Aux Bldg El. 0 Ft Control/Aux/Reactor Building _

3 Cable Spreading Room Control/Aux/Reactor Building_

4A RHR Pump Room Control/Aux/Reactor Building

4B AFW Pump Room Control/Aux/Reactor Building

5 Battery Room A Plant Wide Components

6 Battery Room B Plant Wide Components

9 SWG Access Room Plant Wide Components

10 Switchgear Room A Plant Wide Components

11 Switchgear Room B Plant Wide Components

14 Stairway Plant Wide Components

7 Containment Containment

8A DG-A Room Plant Wide Components

8B DG-B Room Plant Wide Components

12 Turbine Bldg El. 0 Ft Plant Wide Components

15 Battery Room 1 Plant Wide Components

13 Yard Plant Wide Components

14 Intake Structure Plant Wide Components

2-59
Workshop Problem Set 06-11

Transient Ignition Source Weighting Factors: An NPP is composed of three compartments

with the following characteristics:

Compartment 1:

* Houses the Steam Driven Auxiliary Feedwater Pump

" The pump has required major maintenance once per year

* The room is at a comer of the Auxiliary Building separated from other parts of the

building with 3-hour rated walls and one access door

* The lubricating oils of this and other large safety related pumps are stored in this room.

* All cables are in open bottom and open top cable trays

* The total amount of cables in the room is 1,000 lbs.

Compartment 2:

* Houses the one of three High Pressure Injection Pumps

* The pump has required major maintenance once per three years

* The room is at a comer of the Auxiliary Building separated from other parts of the

building with 3-hour rated walls and one access door

* There are no other items in this room except for the pump.

* All cables are inside conduits

" The total amount of cables in the room is 1,000 lbs.

Compartment 3:

" Houses 480VAC MCC

" The MCC has never required any major maintenance since installation 15 years ago

" The room is the passageway between the radiation control and other parts of the

Auxiliary Building

" The room contains coveralls and other radiation protection related clothing items

" All cables are in open bottom and open top cable trays

" The total amount of cables in the room is 10,000 lbs.

2-60
A. Enter the influencing factors for each compartment and category:

Influencing Factor Cable Run (selfignited cable

Compartment Maintenance Occupancy Storage fires)

Compartment 1 I. 4 4 +

Compartment 2

Compartment 3 + + 4

Total

B. Calculate the ignition source weighting factors for each compartment

Transients fires Cable fires Cable Run (selfCompartment General caused by caused by Cable cable Transients welding and welding and ignited cable

cutting cutting fires)

Compartment 1

Compartment 2

Compartment 3

Total

C. Calculate the ignition frequencies for each compartment

Transients fires Cable fires Cable Run (selfGeneral caused by caused by Cable cable

Transients welding and welding and ignited cable

cutting cutting fires)

Total Location 3.90E-03 9.70E-03 1.60E-03 4.40E-03

Frequency (Iry)

Compartment 1

Compartment 2

Compartment 3

2-61
Transients and Cable Fire (Count. kInition Source Weiqhtinq Factor and Frequency)

Count Weighting Factors Frequency

C (1) C - - - 0) - n - - a, -- U -

CO : -3C Q) LL0 0 a) -- 0- Do "

0 o CC - C• CnW- C: 0 0, Q)c 0~: 0 C ~~~C - io

0 x

Control Aux. / Reactor Building

1 Main Control Room 300 1 10 10 300 0.64 3.5E-01 0.2 2.5E-03 5.6E-04 1.9E-03

2 Aux Bldg El. 0 Ft 6 1 1 1 6 0.09 7.0E-03 0.2 3.5E-04 1.1E-05 1.9E-03

3 Cable Spreading Room 549 1 1 1 549 0.09 6.4E-01 0.2 3.5E-04 1.0E-03 1.9E-03

4A RHR Pump Room 1 1 1 1 1 0.09 1.2E-03 0.2 3.5E-04 1.9E-06 1.9E-03

4B AFW Pump Room 1 1 1 1 1 0.09 1.2E-03 0.2 3.5E-04 1.9E-06 1.9E-03

Total 5 14 14 857 _ ______3.90E-03 1. 60E-03 9.70E-03

Plant Wide Components

5 Battery Room A 1 1 1 1 1 0.05 4.2E-04 0.03 4.5E-04 8.3E-07 1.5E-04

6 Battery Room B 0 1 1 1 0 0.05 -- 0.03 4.5E-04 -- 1.5E-04

9 SWG Access Room 1.6 1 1 1 1.6 0.05 6.7E-04 0.03 4.5E-04 1.3E-06 1.5E-04

10 Switchgear Room A 10 3 1 3 30 0.11 1.3E-02 0.09 1.1E-03 2.5E-05 4.6E-04

11 Switchgear Room B 80 3 1 3 240 0.11 1.OE-01 0.09 1.1E-03 2.OE-04 4.6E-04

14 Stairway 0 1 1 3 0 0.08 -- 0.03 7.5E-04 -- 1.5E-04

7 Containment 0 1 1 1 0 0.05 -- 0.03 4.5E-04 -- 1.5E-04

8A DG-A Room 218 3 1 1 654 0.08 2.7E-01 0.09 7.5E-04 5.5E-04 4.6E-04

8B DG-B Room 218 3 1 1 654 0.08 2.7E-01 0.09 7.5E-04 5.5E-04 4.6E-04

12 Turbine Bldg El. 0 Ft 80 10 1 3 800 0.21 3.3E-01 0.31 2.1E-03 6.7E-04 1.5E-03

15 Battery Room 1 0 1 1 1 0 0.05 -- 0.03 4.5E-04 -- 1.5E-04

13 Yard 0 1 1 1 0 0.05 -- 0.03 4.5E-04 -- 1.5E-04

14 Intake Structure 6 3 1 1 18 0.08 7.5E-03 0.09 7.5E-04 1.5E-05 4.6E-04

Total 32 13 21 2398.6 1 1 1 1 1 9.90E-03 2. OOE-03 4.90E-03

2-62
Ignition Frequencies by Bin and Compartment (part I of 2)

Co

CO0)

0

0

-)

0

C-)

w)

aL

E

:3a--

0

rj) C

LD(-D

CD

0

o9

Q.

E

0

C--

U o9 rnCa)

0

w

00U

Co

0a)

C LL

-C C

M <

E,

E

I0

U)

0) 0

Cn

(D

0)

Generic Frequency 7.5E-04 6.1E-03 2.1E-02 2.4E-03 1.8E-03 4.6E-03 4.5E-02 1.5E-03 2.1E-02 9.9E-03 9.9E-03

Compartment and Associated Freq.

1 Main Control Room 1.1 E-02 3.3E-04

2 Aux Bldg El. 0 Ft 7.2E-03 2.OE-03 6.OE-03

3 Cable Spreading Room 6.2E-03

4A RHR Pump Room 7.2E-03 2.OE-03 3.OE-03

4B AFW Pump Room 6.4E-03 6.0E-03

5 Battery Room A 4.7E-04 2.5E-04

6 Battery Room B 9.1E-04 2.5E-04

9 SWG Access Room 1.1 E-02 9.9E-03

10 Switchgear Room A 1.5E-02 6.OE-04 7.9E-03 3.8E-04 5.0E-03

11 Switchgear Room B 1.7E-02 I 6.OE-04 7.9E-03 3.8E-04 5.0E-03

14 Stairway 6.6E-04 I

7 Containment 3.2E-03 6.6E-04 3.OE-03

8A DG-A Room 1.8E-02 1.1 E-02

8B DG-B Room 1.8E-02 1.1E-02

12 Turbine Bldg El. 0 Ft 6.5E-02 2.5E-04 2.4E-03 6.OE-04 1.9E-02 7.5E-04 3.0E-03 9.9E-03

15 Battery Room 1 4.5E-04

13 Yard 2.6E-03

14 Intake Structure 1.1E-03

2-63
Ignition Frequencies by Bin and Compartment (part 2 of 2)

" " Q)

C~ 0

(CU

CU

0m

C

rY

C0

C-)

x

0

c

0

0-

U)

a)

(I)

Cn

EL

E

U- LL

(0

H0)

L..

x

w

(D

H

c-C• Q)

0) ~00

(9

HGeneric Frequency 2.2E-03 2.5E-03 4.4E-03 1.9E-03 [1.6E-03 1.3E-02 9.5E-03 3.9E-03 6.5E-03

Compartment

1 Main Control Room 2.5E-03 9.OE-04

2 Aux Bldg El. 0 Ft 1.8E-05 7.7E-06

3 Cable Spreading Room 1.6E-03 7.1E-04

4A RHR Pump Room 3.OE-06 1.3E-06

4B AFW Pump Room 3.OE-06 1.3E-06

5 Battery Room A 3.OE-06 1.3E-06

6 Battery Room B

9 SWG Access Room 4.8E-06 2.1E-06

10 Switchgear Room A 3.OE-05 1.3E-05

11 Switchgear Room B 2.4E-04 I1.OE-04

14 Stairway

7 Containment

8A DG-A Room 6.5E-04 2.8E-04

8B DG-B Room 6.5E-04 2.8E-04

12 Turbine Bldg El. 0 Ft 2.4E-04 1.OE-04 9.5E-03 3.9E-03 6.5E-03

15 Battery Room 1

13 Yard 2.2E-03

14 Intake Structure 1.8E-05 7.7E-06

2-64
Session 3: Scoping Fire Modeling

2-65
Slide 1 Notes:

*'U.S.NRC E~~~ KICIOi

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module III: Scoping Fire Modeling Task 8

and Appendix F

Joint RES/EPRI Fire PRA Course

September and November 2008

Bethesda, MD

IACCoftabortio, of U.S. NRC Office of Nucl~earRegulatory Research (RES)&S Elactrio Po-~ Research I,,otitute (EPRI)

Slide 2 Notes:

I SCOPING FIRE MODELING Objectives

The objectives of this module are:

* Describe the process of screening ignition sources

* Describe the concept of zone of influence (ZOI)

* Describe the recommended walk down

* Review the walk down forms

* Describe how to update the fire ignition frequencies

calculated in Task 6 with the screening results

Joint Ft. PRA CoG-, Sept d No, 2008 7 A Ctooo~ra s. NRC OffS NM050 Regulotoy

Module 4: Scoplng R. Modelng Task 8 & Appendx F (e500h IRES) S El0ti E P - o sealh h s u- (EPRI)

2-66
Slide 3 Notes:

SCOPING FIRE MODELING

Interfaces

* Inputs for this task

- PRA equipment list, Task 2

- List of ignition sources in each compartment, Task 6

- Room geometry

- Types of ignition sources and targets

* Output from this task

- Revised compartment fire ignition frequencies

- List of potential fire scenarios to be analyzed in Task 11

Jodnt Fkv PRA Cour-, Sept & Nov. 2008 Soo 3 Co'3OOsoq 000U0S NOOC 0*fae NN WRefu00oy

Modu.e t Soopig S RC R. Mo ig 7t k 8 & AppeWndi F -ro (RES) &A7.8t0 P0o- e Re0 s508 (FRlRt)

Slide 4 Notes:

! Screening SCOPING Ignition FIRE MODELING Sources

Any ignition source can be screened if a postulated fire will

not damage or ignited equipment in the compartment.

* By screening the ignition source, its frequency contribution

is eliminated, reducing the compartment frequency.

* It is recommended to use the 98th percentile of the

probability distributions for peak HRR.

* A walk down is strongly recommended.

Jotnt Fim PR. C-e Sept & Nft, 2W8 d A Cdlob°stonaUS NRC Or.- °- N st e o Y

M 'od N#: 0Splg R• Modlng T. k 8 & AppdiF R.r-- (-RES) .V-eoerRsaa&00 7s5,00a (E-R0

2-67
Slide 5

I SCOPING FIRE MODELING

The Zone of Influence (ZOI)

The zone of influence is the region in the compartment where a

target will be damaged if exposed to fire conditions generated by a

specific ignition source.

* The ZOI has 5 distinct regions:

- Flames

- The fire plume

- The ceiling jet

- The hot gas layer

- Flame radiation region

t (* Fla= radiaton rmgon

Joint Fire PRA Course, Sept. & Nov. 2008 Slide 5

Module #: Scoping Rre Modeling Task 8 & Appendix F ..................-........

A Collaboration of U. S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-68
Slide 6 Notes:

! SCOPING FIRE MODELING Task 8: Recommended Steps

5 steps for conducting Task 8

1. Preparation for walk down

2. Plant walk down and screen ignition sources

3. Verification of screened ignition sources

4. Calculation of severity factors

5. Calculation of revised fire frequency

Motfp. - PRS Conp.. SRM S Nao. TOO sind . Coý aa.4O pi U NRC oit.W o== NR.-m.Pay Modah. t• Scoping RA Maodeap Task l AppanallaF Rt~rch (RES) & lectric PowaipRe$arih •ippal PEeRt

Slide 7 Notes:

! SCOPING FIRE MODELING Step 1: Preparation for Walk down

It is recommended that walk down forms are prepared for each

compartment to be visited

Create a list of ignition sources in each compartment. - Equipment counted in Task 6

- Flag equipment in the PRA equipment list created in Task 2

Assigned a HRR to each ignition source (98th percentile of the pdf)

Workshop Problem 08-01

Collect damage criteria information for the equipment in the room

- Qualified/Unqualified cables, solid state equipment etc.

Workshop Problem 08-02

a Develop and document zone of influences in each

compartment

,0o01 Ra. PP.A Cou., Sept Nay. ftol SOa 2008005 S a 4l. Ol U.S. NRC oa l MaduI. #: acapina PR Madeing Tak 8 & Appendix F PRES) (ebeJi a 8.0,5 P& RaOý PO&O. (EPRO

2-69
Slide 8

Notes:

2-70
Slide 9

SCOPING FIRE MODELING

Step 1: Alternative Models for Zone of Influence

- Smoke or hot gas layer: MQH model

T = 7ýb + 6.85. OA hkAT Jt 

A,,Cd~k T Sok

Lk. d4 - tc, th t~F :::t < tIth 2 h, t tp

h= -th t>_tp 4. kl m "Cp) 

dFlame raiaontexm

Input Parameters:

•T.m,: Ambient temperature (0c)

.Qf: Fire heat release rate (kW)

-A.: Opening area (or sum of opening areas) (M2

) 'J

*H.: Height of opening [m]

-AT: Internal surface area of the room (not including opening area) (M2

)

*k: Thermal conductivity of wall material (kW/m- 0

C)

*dm: Density of wall material (kg/m 3

)

:c : Specific heat of wall material (kJ/kg-°C)

*th: Wall thickness (m)

•t: Time value (sec)

Joint Fire PRA Course, Sept. & Nov. 2008 s A Collaboration of U.S. NRC Office of Nuclear Regulatory

Module #P Scoping Fire Modeling Task 8 & Appendix F Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-71
Slide 10

p

SCOPING FIRE MODELING

Step 1: Example Calculation for Room Temperature

T=T•,,b +6.85.

Skd:Ct t < tp

I L- t >--tp

Qf • 2 1/3

A0 ýH 0 hk AT

th

2

tP =.c -

MQH Temperature Correlation

Inputs

Ambient temperature [C] 20

Duration [sec] 1200

Opening area [m2] 3

Height of opening [m] 3

Room length [m] 37

Room width [m] 37

Room height [m] 8

Thermal conductivity [kW/mK] 0.0014

Density [kg/m3] 2000

Specific heat [kJ/kg] 0.88

Wall thickness [m] 0.6

HRR [kW] 9500

Results

Room Temp [C] 327

hk =

. tin

Joint Fire PRA Course, Sept. & Nov. 2008 S Shlide 10 I

Module #: Scoping Fire Modeling Task 8 & Appendix F 2 .

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-72
Slide 11

SCOPING FIRE MODELING

Step 1: Alternative Models for Zone of Influence

Flame height and fire plume: Heskestad's models

L = 0. 2 3 5Q0 / -1.02D

Input Parameters:

*RO: Fire heat release rate (kW)

*D: Fire diameter (m)

S= Ta.b "+- 25 (kfOf (1- Y5 5/3

SK((Hp-Fe)-Zo)

Input Parameters:

•Tab: Ambient temperature (0C)

Skf: Fire location factor

-Qf: Fire heat release rate (kW)

*Fe: Fire elevation (m)

.HP: Target height measured from the floor (m)

-Xr: Irradiated fraction of the heat release rate (FIVE recommends 0.4)

•1D: Plume diameter (m)

i ............................ .

Joint Fire PRA Course, Sept. & Nov. 2008 e A Collaboration of U.S. NRC Office of Nuclear Regulatory

Module #: Scoplng Fire Modeling Task 8 & Appendix F I..,........................ Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-73
Slide 12 ! SCOPING FIRE MODELING

Step 1: Example Calcs for Flame Height and Plume Temp

L =O.235Qf Y5.-.

(kf -- (1 . - r 2/5 y /

3

Tpl = Zamb +25 ((H•H -Fe j- zo)

z.=0.083of Y - 1.02D

Heskdestad's Flame Height Correlation

Inputs

Fire diameter [m] 0.6

HRR [kW] 250

Results [m]

Flame height [m] 1.5

Heskestad's Plume Temperature Correlati

Inputs

Ambient temperature [C] 20

Fire location factor 1

HRR [kW] 1375

Fire elevation [m] 0

Target Elevation [m] 3.7

Radiation Fraction 0.40

Fire Diameter [m] 1

Results

Plume Temp [C] 328

Joint Fire PRA course, Sept. & Nov. 2008- l.de.12-

M o d u le # : .S o p in g F ir e M o d e lin g T a s k 8 & A p p e n d ix F - . .............. . .....

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-74
Slide 13 Notes:

! Step SCOPING 1: Related FIRE FAQMODELING

FAQ 08-0043

- Issue:

* Guidance for placement of a cabinet fire (the source location) suggests

inspecting cabinet contents and placing fire at fuel location

* Applicants would prefer a "one size" approach less conservative than

placing on top of cabinet that would not require internal inspection

- General approach to resolution:

* RES/EPRI teams are debating merits of general application of fire

protection SDP approach - place fire 1 foot below cabinet top (unless top

is unsealed or vented)

- Status: Open

* Team position has been drafted and is under review

* Staff final review pending

FoW . PRA Co- S~t & Mo.2ý ___ A Coýaod US. RC.Nn . ýwyO

MoA.A. e-Scopi,,g .dMOSQ Th.* A APP~nd5 pý (RES) & I ý PR- (EPRI)

2-75
Slide 14

I SCOPING Step 1: Alternative FIRE MODELING Models for Zone of Influence

- Flame Radiation: Point Source Model

qirr 4 •R 2

Input Parameters:

*Qf: Fire heat release rate (kW)

*R: Distance from flames (m)

*Xr: Irradiated fraction of the heat release rate (FIVE recommends 0.4)

*D: Fire diameter (m)

Joint Fire PRA Course, Sept. & Nov. 2008 Slide 14

Module #: Scoping Fire Modeling Task 8 & Appendix F ............ .

A Collaboration of U. S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-76
Slide 15

SCOPING FIRE MODELING

Step 1: Example calculation for flame radiation

•. ifQf X

qirr - 4;7R2

Point Source Flame Radiation Model

Inputs

Fire heat release rate [kW] 317

Radiation fraction 0.40

Distance from flames [m] 1.5

Results

Heat flux [kW/m2] 4.5

Workshop problem 08-03

Joint Fire PRA Course, Sept. & Nov. 2008 Sl

Module #: Scoplng Fire Modeling Task 8 & Appendix F

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-77
Slide 16 Notes:

! SCOPING FIRE MODELING Step 2: Plant Walk down and Screening IS

During the walk down, equipment in the room is subjected to

fire conditions from each ignition source using the ZOI.

Take the opportunity to verify & improve task 6 counting

Document location of ignition sources and reasons for screen/noscreen decisions '

If ignition sources are not screened, document location of affected

equipment and which fire generated condition affected it.

Do not screen:

Oil fires

Cables

Interconnected cabinets

Workshop problem 08-04

Joint Fke pRA Cou-C. Sept & Nov. 2W.8 a C caoMeo- ol UC. NRC Off. o -Ndee'RWMMy

Module #: Sopping Fm MdeIg 'sek 8 &Appendixr ReFreM (NEC) A Rlednu PoerResr lI~tle ipRIi

Slide 17 Notes:

! SCOPING Step 3: Verification FIRE MODELING of Screened IS

It is important to verify that fire damage to the ignition source

itself is not risk significant

1. Do not screen equipment in the PRA equipment list

2. If loss of the ignition source results in a trip (automatic or

manual) but no equipment contributing to the CCDP are

lost, compare the ignition source fire frequency with the

random frequency of the trip it causes.

3. If loss of the ignition source results in both a trip (automatic

or manual) and loss of one or more components

contributing to the CCDP, add a fire-induced sequence

using the ignition source fire frequency and the

corresponding CCDP model with the damaged components

set to fail.

ointr e PRAC.• , Sept. & Nov, 2008 C, ! 0 CIebonetnuiS.C NRCOwiuee-dtntRegiStory

Module 0: Sopfnt RF Modeling Tlsk 8 d Appendix F Reeeeh (RES) A Seadc Powex Re.-eI x- (EPRO

2-78
Slide 18 Notes:

! SCOPING FIRE MODELING Task 8: Calculation of Severity Factors

For each unscreened ignition source, calculate the severity

factor using the appropriate probability distribution for peak

HRR.

* Determine the heat release rate required for damaging

equipment

* This require information gathered during the walk downs!

Joint FE PRA CoGr-., Sept. & NOV. 2008 A C - lWoOc ýo UtS. NRC O*2. dt Nu Rego6(oy

Moduke N: Soop/ng R Mod*Rng Tsu 8 L Appendi F R.-e (RES) & eLOtlo PO R.O-btIt - (EPR)

2-79
Slide 19

SCOPING FIRE MODELING Task 8: Calculation of Severity Factors

I~~~~T 6 &aT.O.dC. Mason~1 t.1s~~r C-... 14. b... 8a )8di ~m i~s.th t Unqiaiodt C"). Rt. tno a'm.t 08. Ca") &mO. ..dDz.m

Pr

Q (kW)

HRR Gamma

kW (Btuls) Distribution

Case Ignition Source HRR 98th P

1 1 Vertical 

to one cabinets with qualified cable, fire limited 69 211 0.84 59.3 cable bundle

2 Vertical cabinets with qualified cable, fire in 211 702 01 216

more than one cable bundle

3 Vertical cabinets with unqualified cable, fire 90 211 16 41

limited to one cable bundle

4 Vertical cabinets with unqualified cable, fire in 232 464 2.6 67.8

more than one cable bundle closed doors

L- 08". 56d 1A9.)

* o(o) 63(1) 36u() o0

2 MO(D) ios('00) 00(76) 0213

3 66N,6"1 'sa1,01 'W (INA) e

4 i88(188) 2,1(2"o) 18o(12) o5

6 ±9a1250) 297(70 M8(27j) &07"

7 31720( 6(300 3" ""1323) 00"s

a M8"OW) 32 ('" *D. (373) 000'

o Work(sho problem) 0511

61 ~ ~ se 10to 47906) 1(73) 0-6

I I 9±9(016) sw(593) 661(82) 0964

U. 5611(m) ioo (NO1 MW(2 660

13 80030.0) 406(4"1 GU686(3 o611

1a 868(88) M72(01 M68(6229 000,

Is '78788 '*

9 

Ot1)72) 0.001

*Workshop problem 08-05

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

5 Vertical cabinets with unqualified cable, fire in 232 1002 1 0.46 1 386 more than one cable bundle open doors I

6 Pumps (electrical fires)

7

8 142 317 1 1.8 1 57.4

Joint Fire PRA Course, Sept. & Nov. 2008 Slide 19

Module #: Scoping Fire Modeling Task 8 & Appendix F ........................ I 

Notes:

2-80
Slide 20

I SCOPING FIRE MODELING

Task 8: Calculation of Revised Fire Frequency

Fir# Ana __________1_20

coprneeer _t____________1___

I. -- tn•t i

_ _ I-* _I

IRR Cacuted Critical 98th

E901) ID

ýablnet A

:eabial a

:abifet C

Fire Coeditbn

Flames

Plume

cftmhq lot

Dist to Tn•#mq

49 1___ 21i j N 34E-01 j 1.0E.04 3!ZE.

401 211 Yes G.OE+OO t.OE-04 0

4870 211 Yes I 0.OE,,O

o"arit .eiaj

Joint Fire PRA Course, Sept. & Nov. 2008 Slide 20

Module #: Scoping Fire Modeling Task 8 & Appendix F ...........................

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-81
Slide 21 Notes:

! SCOPING FIRE MODELING Concluding Remarks

Task 8 is intended for screening fixed ignition sources. As a

result of the screening, the compartment frequencies may be

reduced, and a preliminary list of potential fire scenarios for

detailed evaluation in Task 11 is developed.

* A detailed walk down is recommended

Analysts should take the opportunity to review the

equipment count made for task 6 and/or improve it.

J.int Frk PPA Co-' SPPt & ft,' 2W8 FSOP A C -LOanmoO 0a U'S. SC Nn WO sfl.N . R.nuOýf

Modu?. #: S, g Fr Modelng To 8 & ApOndl F P - r.0 RES] & 8.0000 R 0000tW -O0 (EPR5o

2-82
Session 4: Heat Release Rate

2-83
=. .

Slide 1 Notes:

-USNRC E 2 1SACH NSITUTE

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module III: Heat Release Rates

Appendix G

Joint RES/EPRI Fire PRA Course

September and November 2008

Bethesda, MD

A Collaboration of US, NRC Office of Nuclear Regulatory Research (RES) & Electric Pow-r Res...rh Institute (EPRIO

Slide 2 Notes:

HEAT Objectives RELEASE RATES

The objectives of this module are:

1. Define heat release rate and heat release rate profile

2. Review the recommended peak heat release rate values

for typical ignition sources in NPP

3. Describe the method provided for developing heat release

rate profiles for fixed and transient ignition sources in NPP

NOTE: Appendix G recommends values for ignition sources only. Heat release rates associated with fires propagating

outside of the ignition source have to be evaluated

accordingly.

Joint Fir PRA course. Sept. & Nov. 2008 a A C o S US. NRC 500 o 0 00500000

Module /0.0 H.1 RaShn. R... Appeo-.do S 00005 (RESG & 00..e R0- a 220020. -0 (pR50

2-84
Slide 3

!HEAT RELEASE RATES Definition

Definition: Heat generated by a burning object per unit time.

* Q=h".Allc- A BTU/secorKW

* m" is burning rate [kg/s-m2], AHC is heat of comb [kJ/kg], A is

area [M2]

* Equivalent terms: energy release rate, fire intensity, fire

power

* HRR profile describes fire intensity (Q) as a function of time

Q --

2oý .a) 0

Time

Joint Fire PRA course, Sept. & Nov. 2008 Slide 3 j A Collaboration of U.S. NRC Office of Nuclear Regulatory

Module IIll Heat Release Rates Appendix G . Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-85
Slide 4 Notes:

HEAT RELEASE RATES HRR Profile

The HRR profile can be expressed as a constant or as a function of time

* Incipient stage: Not recommended to be modeled

- Duration and intensity are uncertain

* Growth: Depends on the fuel and geometry of the scenario

- Based on engineering judgment and/or experimental observations

* Fully developed: Usually after the fire reaches its peak

intensity

- Also known as steady burning

- Starts at ignition if the growth period is not considered

- A constant fire intensity should the the peak heat release rate of the

profile

* Decay: In general, less hazardous conditions than the growth

and fully developed stage

Join Fie PRA oounae. So . & Nov. 2008 5 A Coh lbn of U & NRC Ot0 WNueNRegatWr

Module M: Hunt RCeOese fthes Apunndll G •W.OO (JRES) .E no, r R blod- (0Ro0

Slide 5 Notes:

HEAT RELEASE RATES HRR Profile - Related FAQs

FAQ 08-0045 Cabinet Fires (Status: Open)

- Issue:

* Fire growth recommendations for electrical cabinets does not include

consideration of an incipient stage (e.g., pre-ignition heating and

generation of un-burned pyrolysates which might be detected)

- General approach to resolution:

. No clear resolution approach has yet been developed

- Status:

* A problem statement has been generated

* FAQ may be withdrawn - not amenable to short-term solution

Joint FiR. PRA -ou00, SOO & Nov.20U8 O A d n o.S NR0 O8- Nd'Re0ýtOY

Modute 08: Heet Relese 4-ao Appendto G Oe.,h (RES-) 8 1-8d PO Re - K 000800 00ýRO

2-86
Slide 6 Notes:

HEAT HRR Profile RELEASE - Related RATES FAQs (continued)

FAQ 08-0052 Transient Fires (Status: Open)

- Issue:

No guidance on fire growth times for transient fires

* Guidance not clear as to which non-suppression curve would apply to

transient fires in the MCR (i.e., transient curve or MCR curve)

- General approach to resolution:

* Review existing test data and develop guidance for transient fire

growth times

* Clarify non-suppression curve application for this case

- Status:

* Initial team position drafted and undergoing review within the teams

* Staff and industry reviews pending

",t Fim PRA couae, Sept No&, 2008 A dS. U NRC ORC od NW Reggtwy

Modue M: Hweee e. Rs Append,& G -.... 1 (RES) A 0,etrc Fewer R- -h on (EPRI)

Slide 7 Notes:

! HEAT RELEASE RATES HRR Profile - Related FAQs (continued)

FAQ 08-0044 Pump Oil Fires (Status: Open)

- Issue:

* Guidance for large oil spill and fire is generating conservative results

especially in the case of MFW pump fires (high frequency of large

release compared to experience base)

- General approach to resolution:

* Provide an alternative approach and revised fire frequencies for leaks

and spills from higher volume circulating oil/lubrication systems

- Status:

* General consensus that a revised treatment is appropriate and

.needed

* RES/EPRI team discussion of the specific resolution approach

continues, reviews ongoing

* NRC 805 team and industry 805 task force reviews pending

Join Fire PRA -o00, Snpt & No- 2008 [Ž;L7 A ý &bSNn o0 50 S NRCOY 100Nu 00 Re

Module 1: Het Reftse Rates Appendix G - - (R-) I - - - - - f

2-87
Slide 8 Notes:

HEAT RELEASE RATES Fixed Ignition Sources

The methodology recommends heat release rate values for

various fixed ignition sources

* Vertical cabinets

- Open/closed

- Qualified/Unqualified cables

* Pumps (electrical fires)

* Electric motors

* HRR for flammable liquid fires should be calculated as Q0=Ih.AH .A

* Separate guidance for cables, pressurized oil and hydrogen

fires

Join FAin PRA ,- S.PN. & 2008 so a A C, RO-o 4 US NRC 0 oov, 4 8Nu 010y

ModuM W: Hflt Re.e RAM Appendlx G R nh fiS) & 0- P n 200. - R0

Slide 9 Notes:

HEAT Recommended RELEASE Peak RATES HRR Values

Recommended peak HRR values were developed based on

expert judgment

* Expert panel included the EPRI/NRC-RES Fire Risk Requantification Study research team with expertise in fire

behavior/phenomena.

* Values are expressed as probability distributions. The panel

identified the 7 51h and 9 8 th percentiles of the distribution for

peak HRR.

* Primary sources of information included NUREG/CR 4527

and VTT publications

* Gamma distribution selected:

- Only positive values starting at 0 kW

- Values in the same order of magnitude

Joint Fmr PRA 4u0 , Sept. & NoV. 2008 A COPSa0oIIO of US NRC Offico NusJe0Reuto

ModUu- IhlH Ries W---0 e Rats f(RES) APPlo40x G E-.ttdOPor Roe, h 0nStO*. (E-)

2-88
Slide 10

I Recommended HEAT RELEASE Peak RATES HRR Values

Example distribution developed

by the expert panel

• 75 th = 232 kW

* 98th = 464 kW

• z=2.6

* { =67.8

Joint Fire PRA course, Sept. & Nov. 2008 . .0

Module It. Heat Release Rates Appendix G

Peak HRR Distribution

0 500

HRR

1000

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-89
Slide 11

IHEAT RELEASE RATES

Recommended Peak HRR Values

HRRHRR Gamma Distribution

Ignition Source kW (Btufs)

75th 98th Ot 0

Vertical cabinets with qualified cable, fire limited to 69' 211 2 0.84 59.3

one cable bundle (65) (200) (0.83) (56.6)

Vertical cabinets with qualified cable, fire in more than 211 2 702 3 0.7 216

one cable bundle (200) (665) (0.7) (204)

Vertical cabinets with unqualified cable, fire limited to 90£ 211 2 1.6 41.5

one cable bundle (85) (200) (1.6) (39.5)

Vertical cabinets with unqualified cable, fire in more 232 - 464 ' 2.6 67.8

than one cable bundle closed doors (220) (440) (2.6) (64.3)

Vertical cabinets with unqualified cable, fire in more 232 " 10027 0.46 386

than one cable bundle open doors (220) (950) (0.45) (366)

69 2112 0.84 59.3 Pumps (electrical fires) (65) (200) (0.83) (56.6)

M 32 69 2.0 11.7 MOtOrS (30) (65) (2.0) (11.1)

*See report for footnotes

Joint Fire PRA course, Sept. & Nov. 2008

Module Ill: Heat Release Rates Appendix G Slide 1 1 A Collaboration of U.S. NRC Office of Nuclear Regulatory ......................................... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-90
Slide 12

I HEAT RELEASE RATES

Fire Growth in Electrical Cabinets

The methodology suggests a fire

growth rate for electrical cabinet

fires

* The fire grows to its peak HRR

in approximately 12 min

* The fire burns at its peak HRR

for approximately 8 min

" Based on experiments reported

in NUREG/CR4527

Joint Fire PRA course, Sept. & Nov. 2008 Slide 12

Module IIl Heat Release Rates Appendix GI

Units in MIneet Test Time to Peak Steady Burning Thne to DecOy

STI 7 8 15

1T2 0 11 17

ST3 10 8 18

ST4 14 3 17

ST5 8 9 17

ST6 8 17 25

ST' to 7 25

STO 1( 20 30

ST9 10 10 20

$T10 10 20 30

ST11 1I 2 20

PCT1 11 10 21

PCT2 12 2 14

PCT3 13 14 27

PCT4a 1e 0 16

PCT4c 16 0 16

PCT5 17 0 17

PCT6 11 0 11

Test 21 4 14 Il

Tt 23 10 0 10

Tes 24 12 0 12

Anrage 11.4 7.1 19

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-91
Slide 13

HEAT RELEASE RATES

Fire Growth in Electrical Cabinets

The t

2 function is recommended for modeling the growth phase of

the fire ( ( 2

0(t) = MinLQpeakQopeok ~

Heat Release Rate

T time to

~peak

0 5 10 15 20

Time [min]

Joint Fire PRA course, Sept. & Nov. 2008 A Collaboration of U.S. NRC Office of Nuclear Regulatory

M•odule ti Heat Release Rate Anandix f. G ................... ....................... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-92
Slide 14 Notes:

! HEAT RELEASE RATES Assigning HRR Values to Electrical Cabinets

A visual examination of the interior of the cabinet is

recommended

* Identify openings in the cabinet walls

* Identify type of cable: qualified/unqualified

* Identify cable bundles

* Qualitatively determine if a fire can propagate from one

bundle to another

* Select the appropriate peak HRR probability distribution

Jokdu PRA : -,J Spt 4 fte. 2W08S 4 PO R0 d tda 08d RO

M---------- -8* ---- ---- Apeni -aW - 0 .8 (AES) . £00 -08 - 00 -. SfA- (-qP

2-93
Slide 15

I HEAT RELEASE RATES

Examples

By visual examination:

• More than one cable bundle

- Assuming qualified cable, select distribution with 75th = 211

kW, 98th =702 kW

Joint Fire PRA course, Sept. & Nov. 2008 id'e 1- I A Collaboration of URS. NRC Office of Nuclear Regulatory

Module /ill. Heat Release Rates Appendix G .......... eI. ..... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-94
Slide 16

I HEAT RELEASE RATES

Examples

By visual examination:

* Only one cable bundle

* Assuming qualified cable, select distribution with 7 5 th = 69

kW, 98th= 211 kW

Joint Fire PRA course, Sept. & Nov. 2008

Module Ilh Heat Release Rates Appendix G

S A Collaboration of U.S. NRC Office of Nuclear Regulatory

.16 Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-95
Slide 17 Notes:

! HEAT Transient RELEASE RATES Ignition Sources

The peak HRR for transient fires is also characterized with a gamma probability distribution

* Gamma distribution: - 7 51h = 135 BTU/s, 9 8th = 300 BTU/s

- c= 1.9, 3 = 53.7

* Applicable only to localized transient combustibles (trash

cans, etc.)

* Not applicable to flammable liquid transient fires

JOkAt F PRA coc, e, Xect & AbM 2000 B s A Cchb°adU& NRC 0 f °Ncc- w RcccaboY

MOdsM m, H-. RW2as. Rats ARAS- u x G Rescch Ethni Pc..r R rchV0 m• .r (E0R

Slide 18 Notes:

! Concluding HEAT RELEASE RemarksRATES

Peak HRR values are recommended for some typical fixed

and transient ignition sources in NPP fire scenarios

* Values are for localized ignition source (not for fires

propagating outside the ignition source)

* HRR for flammable liquid fires can be calculated from

fundamental equations

* HRR for "solid" ignition sources are generally expressed as

probability distributions based on experimental data and

expert judgment

Joint Fitm PZA C , Sept & Nft. 2,06 WWfcodNuc s A Cootkcf S NRC g00orV

Module C Ht . Res- Ra- Apcun•Wt S R*OaO• ARES) & Cin Pow, Resc In S (EPRG

2-96
Session 5: Fire Severity

2-97
Slide 1 Notes:

(ŽU.S.N RC LICUIC POWEI azei I :ESEARCH INSTITUT,

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module III: Fire Severity

Joint RES/EPRI Public Workshop

September 2008

Washington DC

Collboration of U.S. NRC Ofice of Nuclear Regulatory Research (RES) & VItcS Power Research Institute (EPRO

Slide 2 Notes:

! FIRE PurposeSEVERITY

-A uniform methodology has been developed to define the

severity of a fire.

- Severity factor concept

- Based on heat release rate

- Standardized cases

Fee PRA Workshop, W8, Woshongtf- LC A CoIobomion AS NRC Mao o Mu R .01.R1eatoo

Modlu. t0: I Neal. Fs e S 0.00,5 (RES) POe e h ba l0 'Elm

2-98
Slide 3 Notes:

FIRE SEVERITY

Severity Factor Concept

- Severity Factor is..

- A simplified, one parameter representation of a very complex

phenomenon (i.e., fire) influenced by a large number of factors.

- Defined as the conditional probability that given a fire has occurred,

it is of.certain severity (it is defined here through heat release rate).

- Quantified in combination with Non-Suppression Probability.

Fý. PRA WorkshW. 2W08. ' nt o DC A8 CN0 U n nUS NRG Oý NaN W R uAf

Modul. ID: Fk. S-nW.y R {RES) ESwh &Dodec Powr ,maxh slO (EPR0

2-99
Slide 4

! FIRE SEVERITY

Severity Factor Concept (cont'd)

The combination of Severity and Non-Suppression Factors

are calculated from the following equation: JdJda (t)~

SFk .P,,k = A -t '.Pp tsupp > t)dt

Where:

Pdam(t) : The probability of target set damage before time t.

Psupp (tsupp > t): Probability of suppression taking place after time t

Fire PRA Workshop, 2008, Washington DC

Module IIh Fire Severity

Slide 4 A Collaboration of U.S. NRC Office of Nuclear Regulatory

S...e...1. Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-100
Slide 5

FIRE SEVERITY

Probability of Damage Estimation

* Probability of damage before time t is estimated using

complex fire spread and propagation models.

- Heat release rate is a key parameter of the analysis

- Assuming a known heat release rate, specific features of the

compartment, ignition source, and target set configuration, time to

damage can be calculated.

- Since heat release rate is expressed with a probability distribution,

. the time to damage can be expressed with a probability distribution

Fire PRA Workshop, 2008, Washington DC

Module IIh1 Fire Severity

S A Collaboration of U.S. NRC Office of Nuclear Regulatory .......... dResearch (RES) & Electric Power Research Institute (EPRI)

Notes:

2-101
Slide 6

IIFIRE SEVERITY

Severity Factor Estimation Process

Severity factor is estimated using discretized probability

distributions for heat release rate and non-suppression.

Heat Release Rate (HRR) Heat Retease Rate Time to Damage (t)

54 ==ý HRR Values HRRI HRR2 HRR3 HRR4 .... HRRn

Individual Severity Factor Pt P2 P3 P4 aP

Time to damage 1 t2 tz I .... t I

Prob. of supp. after damage PNSt PNS2 PN-a PNts. PNSn

Fire PRA Workshop, 2008, Washington DC

Module II: Fire Severity

Slide 6 A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-102
Slide 7

FIRE SEVERITY

Heat Release Rate Distributions

The heat release rate of the following equipment classes

have been defined:

HRR (Btu/s)

Case Ignition Source 75t th

75th 98th

1 Vertical cabinets with qualified cable, fire limited to 65 200

one cable bundle

2 Vertical cabinets with qualified cable, fire in more 200 665

than one cable bundle

3 Vertical cabinets with unqualified cable, fire limited 85 200

to one cable bundle

4 Vertical cabinets with unqualified cable, fire in more 220 440

than one cable bundle closed doors

5 Vertical cabinets with unqualified cable, fire in more 220 950

than one cable bundle open doors

6 Pumps (electrical fires) 65 200

7 Motors 30 65

8 Transient Combustibles 135 300

Fire PRA Workshop, 2008, Washington DC

Module Ill Fire Severity .. .de7 I A Collaboration of U.S. NRC Office of Nuclear Regulatory . . Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-103
Slide 8

FIRE SEVERITY Heat Release Rate Distribution - Example

Table E-1

HRR Distribution for Vertical Cabinets with Qualified Cables, Fire

Limited to One Cable Bundle

Heat Release Rate (Btu/s) Severity Factor Bin

Lower Upper Point Value (PI)

1 0 25 10.5 0.446

2 25 50 36 0.219

3 50 75 61 0.129

4 75 100 87 0.078

5 100 125 112 0.048

6 125 150 137 0.030

7 150 175 162 0.019

8 175 200 187 0.012

9 200 225 212 0.007

10 225 250 237 0.005

11 250 275 262 0.003

12 275 300 287 0.002

13 300 325 312 0.001

14 325 350 337 0.001

15 350 Infinity 405 0.001

Fire PRA Workshop, 2008, Washington DC

Module IIl Fire Severity

.lide 8.. . A Collaboration of U.S. NRC Offie of Nuclear Regulatory S. .Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-104
FIRE SEVERITY

Severity Factor for 01

The severity factor fo

established from the

1. Determine the amoun

2. Assign a severity fact

more of the amount o

3. Assign a severity fact

the amount of oil spill

This approach is bein

Fka PRA Wo*sh, 20•0 Wh,•gfwo DC

Mod.). W. Fh S-.Hr

Slide 9 Notes:

il Spill Fires

r oil spills are recommended to be

following steps:

nt of oil that can be spilled in the room.

or of 0.02 to a scenario consisting of 98% or

if oil spilled and ignited.

or of 0.98 to a scenario consisting of 10% of

ed and ignited.

ng revisited in FAQ 07-0044.

S~.g A C~orDhobO U S. NRC OM• dNXSW RSDA.IOV

RrNmoR (RES) & Ekd'Ie Ron, Ren tR (EPRI)

Slide 10 Notes:

! FIRE SEVERITY Severity Factor for Other Ignition Sources

The following notes address ignition sources not covered in

the preceding discussions:

- Cable fires:

* Heat release rate is established using fire propagation modeling

* Severity factor = 1.0 may be used where target damage can be

ascertained

- High-energy arcing faults:

. Severity factor = 1.0 within zone of influence

- Catastrophic transformer fires in the transformer yard

. Severity factor = 1.0 within zone of influence

- Non-catastrophic transformer fires in the transformer yard

* Generally not modeled, otherwise use sevedty factor = 1.0 within zone of

influence

- Other fires in the transformer yard:

* Depending on the item burning, the heat release rate of similar devices

may be used.

Fir PRA Wo5*MoV, 2008, Wos•Rglo DC s A CaIOPoI CO0U.S. NRC DOtN RWnbo

Module I.: Ft Suo1y4 R -h (RES) A Eletri Rowe RAesrch Isfj iePRh)

2-105
Slide 11

I FIRE SEVERITY

Frequency Bins and HRR Distributions

Table 11-1

Recommended Severity Factors... for Ignition Sources in the Frequency

Model

ID Location Ignition Source HRR Distribution Category

1 Battery Room Batteries Electric motors

2 Containment Reactor coolant Pump Pumps (Electrical)/Oil spills

(PWR)

4a Control Room Electrical cabinets Applicable electrical cabinet

4b Control Room Main control board See Appendix L

5 Control/Auxiliary/ Cable fires caused by Assume 1.0

Reactor Building welding and cutting

6 Control/Auxiliary/ Transient fires caused Transients

Reactor Building by welding and cutting

21 Plant-Wide Pumps Pump (Electrical)/Oil spills

Components

Fire PRA Workshop, 2008, Washington DC

Module Ill: Fire Severity

S lide I1 I A Collaboration of U.S. NRC Office of Nuclear Regulatory .. . . Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-106
Slide 12 Notes:

! FIRE SEVERITY Concluding Remarks

- Severity Factor provides an adjustment to ignition frequency

to account for the severity of the fire.

- It is tied to the heat release rate

- It is estimated in concert with probability of non-suppression

- Specific cases have been developed

- Guidance is provided for other cases

Fil, PRA WoRt hop, 2008, Was,,hgblm DC F ACCobotC • ofUS. NRC 0ffi0 N M/ea atOy

ModJ4 88: R.P S.ý,yl4' R..CA (RES) &CMCCCPCwR.SrCA Cn*W (CR88

2-107
Session 6a: Damage Criteria

2-108
Slide 1 Notes:

qft.S.NRC

W

LECTRIC POWE2

Come I "ESIARCH INSTITUTE

EPRIINRC-RES FIRE PRA

METHODOLOGY

Module III: Damage Criteria

Joint RES/EPRI Fire PRA Course

September and November 2008

Bethesda, MD

A CoIlaboration of U.S. NRC Office of NucIearRegulatory Research (RES) & Electric Power Research Institute (EPRI)

Slide 2 Notes:

! Damage Criteria Damage Thresholds

Damage (or Failure) Threshold: the minimum value of an

exposure environment parameter that can lead to the failure

of the damage target of interest within the timescale of the

fire

- Can be a temperature - exposure to high temperatures such as in a

hot gas layer or fire plume

- Can be a radiant heat flux - generally due to direct radiant heating

from the luminous flame zone of a fire

- In theory, it could be a minimum smoke density, but we aren't that

smart (more on smoke shortly)

Joint FiR PIA Course., Sept A N., 2008 sldeS Cdleboatlon dUS. NRC OWie of NXde Reg1datsy

Nodule IN. Damege rii Re(~si, (RS) S Eleatric PWes Recearsh ,Instut (EPR

2-109
Slide 3 Notes:

! Damage Damage Thresholds Criteria

Damage thresholds are of primary interest to Task 8 - Scoping Fire Modeling

- We use damage thresholds mainly when screening out specific fire

ignition sources

* If a fire source cannot damage any target, or ignite any secondary

combustible, then we screen that source out of the analysis as nonthreatening (more on Task 8 later)

- Also Note: If an electrical cable is damaged, we assume that it will

also be ignited

- Arcing when a cable short circuits will ignite the cable based on testing

experience

Joint F.. P'o CoMM,., Sept. A No. 2w0 8 A00o..... f.S.. NRC0.o... .. . R.. ,Y

Module IN. Damps c3fhrie Reseah (RCS) A Sn1fdo Pu0,, R-b-h o -onotofe (EPRA)

Slide 4 Notes:

! Damage Criteria Damage Thresholds

Damage Threshold is specific to the damage target and

procedure deals mainly with the following:

- Electrical Cables

* Thermoset

* Thermoplastic

- Electronics and integrated circuit devices

For other devices (e.g., motors, switchgear, etc.) look at the

cables and supporting controls or electronics

- Example: A pump is fed by power cables, and those cables are

generally more vulnerable to fire damage than the pump itself

Join! Firo PRA Co,•w, Sept. & No. 2008 A C - &ab SonoflU. NRC Oft, Of*Noo Rw uaý

Module Oil Damagp Criora RP-eemh (fRES) A El- o.,f ResO h 1,s(#U, (E0 t)

2-110
Slide 5 Notes:

! Damage Criteria Damage Thresholds

-Some items are considered invulnerable to fire-induced

damage:

- Ferrous metal pipes and tanks

- Passive components such as flow check valves

- Concrete structural or partitioning elements except when considering

random failure likelihood in multi-compartment scenarios

. i.e., we do not consider fire-induced structural failure of concrete

Things you still need to watch for:

- Soldered piping (e.g., air/gas lines that are soldered copper)

- Flexible boots/joints/sleeves on piping (e.g., the Vandellos scenario)

- Exposed structural steel given a very large fire source (e.g.,

catastrophic loss of the main TG set - more later)

[1 ~ USM nR oiaM.Rg, JO FkO PRA CO-, So. & NoW. 2008 hoen ý (RES) NRCONreO. Nu R. (EPRo

Uodul I.N, 0 .. W. O NF_ B- E R-c - EPRO

2-111
Slide 6

Damage Criteria

Damage Thresholds

The following are defined as generic damage thresholds for

the most common damage targets - cables:

Table H-1r Damage Criteria for Electrical Cables - Generic

Screening Criteria for the Assessment of the Ignition and Damage

Potential of Electrical Cables [See Ref 8-1]

Radiant Heating Criteria Temperature Criteria

Cable Type

Thermoplastic 6 kW/m 2 (0.5 BTU/ft2s) 205°C (400°F)

Thermoset 11 kW/m 2 (1.0 BTU/ft2s) 3300C (6250F)

* And electronics:

- 3 kW/m 2 (0.25 BTU/ft 2) and 651C (150'F)

- If needed, assume ignition properties same as thermoplastic cables:

6 kW/m 2 (0.5 BTU/ft2) and 2050C (4000F).

Joint Fire PRA Course, Sept. & Nov. 2008 A Collaboration of U. S. NRC Office of Nuclear Regulatory

Module Ill: Damage Criteria ... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-112
Slide 7 Notes:

! Damage Thresholds Criteria

- For additional rules related to damage criteria, see H.1.1;

e.g.:

- Cables in conduit: potential damage targets, but will not contribute to

fire growth and spread - no credit to conduit for delaying the onset of

thermal damage.

- Cables coated by a fire-retardant coating: treat as exposed cables for

damage purposes - coating may slow the subsequent spread of fire,

but we are NOT specific here.

JO"I Fm PRA Cou-r, Sept. & No, 2MOO Sl,? A Co&boUM oU NRC O N ýRe nU-YR.O,4alo,

MWoIU IRI: DnV.R. 0,0s'.. RImR (RES) 000e00 Po.Re...fh 0004. EPRI

2-113
Slide 8

Damage Criteria

Damage Thresholds

Plant-specific or product-specific damage thresholds may

,be used if appropriate basis is established

- Report provides some references for information specific to many

popular types and brands of cables

- Example: Table..p

Fadlure termper-atures for Spec|ifi Cable products as Reported in Talble 5 of Reference H,2

Ca of CFailure

Manufacturer Decription of Cable Tested Threshold ('C)

Brand Rex Cross-lr.ked polyehylene (XLPE) Ir.sulatior. Chlorosulfonated 385

Polyethylne (CSPE) Jacket. 12 AlIG. 3-Contductor (31C).

Rockbes.os FPhewa0 in. lIfadlJ-on XLF E Ilnsulauon. Neoprene Jacket. 320-322

12 AWG. V/C. eco V

Rav chi lav .Rwol. XLPE Ilsutaion. 12 AWG. 1C. 4500 V 3M--38.

samnuel MOON oekrcth Polyse:. Cros-Linltd Pely*W,.n (XLPO) Intsulation. 12W307

MCPe Jacke., 12 AWG.0 VC and Drain

Anaconda SinGle Conductors Renoved From: Anaconda Y Flam.@ Guard 381

Fa.me Retardant. (FR) Ethylene Propylene (EP). Ethylene

Propyler.e Rubber (EFR) Insulation. Chlcrinated Polyethylene

___ CFEJacbi._2 AWO. 2/C. 8Vl V

AAnaconda naconda Flame-Guard EP. EPR Insulatcn. Indmidual CSPE 324

Jamket. Overall CSPE Jacket. 12 AWG. 31C. 1030 V

Okonite Okolon. EPR Ins,.dation. CSPE Jacket. 12 AWG, IVC.

COO V

387

Joint Fire PRA Course, Sept. & Nov. 2008

Module Ill: Damage Criteria

[Slide 8 •• A Collaboration of U.S. NRC Office of Nuclear Regulatory j Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-114
Damage Criteria

Damage Time

* It is both appropriate a

during Task 11 - Deta

- At the threshold exposi

prolonged (e.g., 30 min

- As exposure conditions

decreases (e.g., to as I

- Consideration of time

assessment of the non

How long do you have

Jo4t FRe PRA Cauos, SW & H-s 2008

WMd.% X. V... Cor•

Slide 9 Notes:

and desirable to consider damage time

iled Fire Modeling

ure condition, damage times may be

iutes or more)

increase in severity, time to damage

ittle as a few seconds)

o damage allows for a more realistic

-suppression probability

to put the fire out before damage occurs?

Slide 10 Notes:

Damage Criteria

Damage Time

Two general approaches to damage time analysis:

- Direct modeling of target thermal response

* Use a fire model to predict the temperature response of the target

* When the predicted temperature of the target reaches the damage

threshold, assume target failure

* Catch: need fire model that does target response calculation

- Empirical approach (e.g. SDP)

Predict the peak exposure condition (temperature or heat flux)

* Use a look-up table to estimate time to damage

* Catch: look-up tables currently only available for generic thermoset and

thermoplastic cables

Join) ri. PRA Cour-. Sopt. & Nov., 2008 1 A Co-abo of olUS NRC Office 0fNslwrReglatoy

Module 5t: O -ge Cdr•fl. Re0a04h (RES) IE- 0.., -oer h nt (-)P8!

2-115
Slide 11

I Damage Criteria

Damage Time

* Example of the

Time to Damage

look-up tables:

Joint Fire PRA Course, Sept. & Nov. 20

Module IIIh Damage Criteria

Table H-5: Failure Time-Temperature Relationship for

Thermoset cables (Table A.7.1 from reference H.6).

Exposure Temperature Time to Failure

oC OF (minutes)

330 625 28'

350 660 13

370 700 9

390 735 7

410 770 5

430 805 4

450 840 3

470 880 2

490 (or greater) 915 (or greater) I

08 Slide 11 A Collaboration of U.S. NRC Office of Nuclear Regulatory

id Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-116
Slide 12 Notes:

! Damage Smoke Damage Criteria

-Appendix T provides an extended discussion of current

knowledge regarding smoke damage

- This is about smoke and the failure of equipment

- It is not about the impact of smoke on people

- We are interested in short-term damage

- Within the time scale of the fire scenario including plant shutdown

- We do not consider longer term issues such as corrosion leading to

failure some days or weeks after a fire

Joint Fite PRA Cou- e Sept. & Nov. 2008 •S;;; 12 A CSd boo o 1W a S0NC - 1-RaO N UCOReato

modf. IM: oal .. cl w R0 (CES) I £ 0 PooCRSCPo- R h tfOeN (EPRC

Slide 13 Notes:

! Damage Smoke Damage Criteria

* Bottom Line: Some components are known to be vulnerable

* to smoke damage, but it takes a dense exposure to cause

short term damage

* So what are the vulnerable components?

- High voltage switching equipment (arcing)

- High voltage transmission lines (arcing)

- Devices such as strip chart recorders that are dependent on fine

mechanical motion (binding)

- Un-protected printed circuit cards (deposition and shorting)

- e.g., exposed within a panel and not provided with a protective coating

Joint Fire PIA Cowne, Sept. & Nov. 2008 S 1 201000000,, oUS NRC 0Cc. o(0N000cRowuat°, Module SOf Dangq. CrOrAS 0.0.h (CEO) 0201 P•oeOt~cp R Oh InsOtt (20100

2-117
Slide 14 Notes:

I Damage Criteria Smoke Damage

- Smoke damage is assessed on an empirical basis:

- We don't set quantitative thresholds

- We don't try to use fire models

- You should consider the potential failure of vulnerable

components due to smoke as a part of your damage target set

JOml Fk PRA Go., SW. & t,. 2MQ8 j. A COPOdtO toS. NRC QIIO. ofR•ty

MoM IN, D,,. " RSfNlofh (RES) & E•f• Pton Rflýoh ý nýlmtl 55PR0

Slide 15 Notes:

! Damage Criteria Smoke Damage

-Assume that vulnerable components adjacent to or

connected to the fire source will be damaged by smoke:

- Within the same electrical cabinet or housing as a fire source

- e.g. given a panel fire, the whole panel is lost due to smoke and/or heat

- In an adjacentcabinet if the cabinet-to-cabinet partitions is not wellsealed

- In a common stack of electrical cubicles

- In a nearby cabinet with a direct connection to the fire source

- e.g., a shared or common bus-duct

Joint Fire PRA Cou-e, Sepf. & Nov. 2,08 ] A Cofto•fot fl S NRC O[SoN INNS ReoCOtoo,

Modue Pt: IM P,.. 541.0 ReS, h (RES) & EOe Poe•. RP- h fmt0, (EPRI)

2-118
Session 6b: Example Problems

2-119
Workshop Problems on Task 8: Scoping Fire Modeling

This handout includes workshop problems on the different steps of Task 8: Scoping Fire

Modeling. Problems are grouped by steps.

Step 1: Preparation for Walkdown

Step 1 has three sub-steps: 1) Estimate heat release rate for fixed ignition source screening, 2)

Target and intervening combustibles damage or ignition criteria, and 3) Develop a zone of

influence.

Workshop problem 08-01:

Step 1.1: Estimate heat release rate for fixed ignition source screening: Assign a heat

release rate to the ignition sources depicted in the pictures of the following Table 08-01. For

this exercise, assume that the plant has a mix of qualified and unqualified cables. The heat

release rates are listed in Table E-1 of NUREG/CR-6850.

Table 08-01: Inputs for Workshop problems 1 = • . 98~~th P retl

Ignition Source Table E-1 Case 98 HPercentile Justification

HRR

Dry transformer

Fire protection panel _________ ___________ ___________

2-120
Ignition Source Table E-1 Case 9 8 th Percentile

HRR Justification

2-121
Workshop Problem Set 08-02:

Step 1.2: Target and intervening combustible damage and ignition criteria: Assign

damage criteria to the ignition sources depicted in Table 08-01. For this exercise, assume that

the plant has a mix of thermoset and thermoplastic cable. Generic damage criteria are listed in

Table H-1 of NUREG/CR-6850.

Table 08-02: Inputs for workshop problem 2

Target/intervening Damage Criteria Justification

Combustible

Cables in a ladder back tray

Cables in a solid tray

Theromset cable in a conduit

Motor operated valve (MOV).

Cabinet with a solid state device

2-122
Workshop Problem Set 08-03

Step 1.3: Develop zone of influence: Calculate the heat release rate required for generating

target damage for the following ignition source/target combination and determine if the ignition

source can be screened. Use the engineering calculations described in NUREG-1805 for

determining the heat release rate value.

Target in the hot gas layer:

* A cable tray target is located near the ceiling in a room approximately 21' by 7' and has

a normally closed door on each end. The room is approximately 20' high. The inside

walls of the MCC room are reinforced concrete. There is one MCC cabinet in the room.

The MCC cabinet has unqualified cable.

2-123
* Target subjected to flame impingement or fire plume temperatures: 0 A vertical cable tray is located 5' ft from a floor based ventilation subsystem.

2-124
* Target subjected to flame radiation:

2 A conduit is located 3 ft from a battery charger with qualified cable.

2-125
Workshop Problem Set 08-04

Step 2: Plant Walkdown: Inspect the ignition source and target combination in the pictures

included in Table 08-03 and determine the appropriate zone of influence calculation necessary.

laDle u0-u0: Inputs for worKshop problems I

Ignition Zone of Influence Distance Ignition Source Source/Target

2-126
Ignition Igniton Source SurceSource/Target Ignition Zone of Influence Distance

i i i

2-127
Step 3: Verification of Screened Ignition Sources

No workshop problem for Step 3.

Workshop Problem Set 08-05

Step 4: Calculation of Severity Factors: Calculate the severity factors for the ignition source

and target combinations listed in Workshop Problem 08-03. Use the results of Workshop

Problem Set 08-03 as inputs to this exercise.

* Target in the hot gas layer

* Target subjected to flame impingement or plume temperatures

" Target subjected to flame radiation

2-128
Workshop Problem Set 08-06

Step 5: Calculation of Revised Compartment Fire Frequency. Determine a revised

compartment ignition frequency for switchgear room A assuming the walkdown results listed in

Table 08-04.

Table 08-04: Summary of Task 8 calculations

Equipme Measur Tab Roo

nt Cou nt u C Fire Fr ed d E-1 le Critical HR R Roo m Hi m Calculat ed HRR Roo m Screen Severe ty Cou nt

Descripti nt Condition Distanc Eas HRR Area Heig e Tern ed Facto Tas

on e (ft) Cas (Table E-()2) (k (F) r kA8 e (ft2 (ih) (k) p(F_

Train A flame or Do Not

4160 V 8 plume 1.7 9 Screen 1350 20 7 N/A No 1.00 8.00

Bus

Train A

480 V 6 flam .9 Do Not 1350 20 401 N/A No 1.00 6.00

Load radiation Screen

Center

Train A

Station flame Do Not

Service 1 radiation 9 Screen 1350 20 336 N/A No 1.00 1.00

Transfor

mer

Battery Train Aflame A plame or 2.9 4 464 1350 20 25 264 No 0.98 0.98

Charger

125 VDC Train Aflame flame or 0.7 4 464 1350 20 1 264 No 1.00 8.00

Bus

Train A flame

125 VDC 1 radiation 2.8 4 464 1350 20 129 264 No 0.60 0.60

Panel

Train A 1 flame

Inverter ine radiation radiation 2.0 4 464 1350 20 64 264 No 0.88 0.88

Table 08-05: Comparison of switchgear room A ignition frequency

Task 6 Switchgear Room A I 1.5E-02

Task 8 Switchgear Room A 1.5E-02

2-129
Session 7: Detailed Fire Modeling and Single Compartment

Scenarios

2-130
Slide 1 Notes:

eU.S.NRC EP2I~

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module II: Task 11a - Detailed Fire

Modeling and Single Compartment Fire

Scenarios

Joint RES/EPRI Fire PRA Course

September and November 2008

Bethesda, MD

I A Colabot,.i of U.S. KNRC Oi.ý oafNMworR.f toty R. h (RES)&& 1f.0tt Po ReS.AR. h fnsd0 (FF0

Slide 2 Notes:

Module I1-10: TOPICS

The objectives of this module are:

* Describe the process of fire modeling for a single fire

compartment

* The outcome of this activity is the extent and timing of fire

damage within the compartment

-o~ Fme FR Coase Spt & ft, 2008 A-ol.O~~ dONSCCreW&eO.Ao, Module 80 Task hft -O.tlýd F Modelig & Sl., 0001RE & 0000. o.o oote (0005 COeopfl,,nt Flr* Socorlos

2-131
Slide 3 Notes:

! Role Module and 11-10: ScopeFIRE MODELING

Fire modeling: An approach for predicting various aspects of

fire generated conditions

- Requires idealization and/or simplifications of the physical processes

involved

- Departure of the fire system from this idealization can affect the

accuracy and validity

* Fire scenario: A set of elements representing a fire events

- Fire source/initiation

- Fire growth

- Fire propagation (room heating, HEAF, intervening combustibles, etc.)

- Active fire protection features, e.g., detection/suppression

- Passive fire protection features, e.g., fire stops

- Target sets, i.e., cables, habitability, etc.

JoWRe PRA C- SW. & 2W8 So. j• A on ,. Modul COMpafe W. T-k Rre It. S-11.r - M&. N -WMo in & Sige -rhRES)& O W (EPRO

2-132
Slide 4

Notes:

2-133
Slide 5 Notes:

! Module Characterize 11-10: Fire PROCESS Compartment

* Information on compartment geometry that can impact fire growth

- Size and shape, e.g., ceiling soffit or beam pocket

- Boundary construction and material

- Ventilation

* Fire protection systems and features

- Fixed detection systems

- Fixed fire suppression systems, water or gaseous

- Manual detection

- Fire brigade

- Internal fire barriers and stops, e.g., ERFBS

* Problem 11a-01, 11a-02

JoRt Fle PRA Co-s.. SWpl. & No, 20M8 A caooot U. NO C O~b. oAtal.wgttov

Modofl T Oath.. ff- Dl d Rn Mocftlng 0 • In ±.h R000h IRESJ & U Sn. PoAr- ,St 000.PR0

C-*ýt Fil. Scen-l0

Slide 6 Notes:

SModule 11-10: PROCESS Identify/Characterize Fire Sources

* Location within the compartment, type, size, initial intensity, growth

behavior, severity/likelihood relationship, etc.

* Estimate frequency of ignition for the ignition source.

* Example of fires events involving typical ignition sources

- Oil or liquid spill fires (Characterization described in appendix G)

- Oil or flammable liquid spray fires (Characterization described in appendix G)

- General fires involving electrical panels (Characterization described in

appendices G, L & S)

- High energy arcing faults events (Characterization described in appendix M)

- Cable fires (Characterization described in appendix R)

- Hydrogen fires (Characterization described in appendix N)

- Transient fuel materials (Characterization described in appendices G & S)

* Problem 11a-03

Jo"t Fm PRA Cou-, Se.t. & No. 2008 Module. I50.00: T 1. O.,tale 5,. Modelng & sl .Sin de A Cd~a~o# otnn dU.S NRC Olc)oo - u Regulato (E Coobpar•,nt Pin Somafloo Oaf 030030P.~oo ,1f EO

2-134
Slide 7 Notes:

! Module 11-10: PROCESS Identify/Characterize Secondary (intervening) Combustibles

- May include,

- Overhead raceways,

- Cable air-drops,

- Stored materials,

- Electrical panels,

- Construction materials, etc.

* The information provided should describe

- Relative proximity of the secondary combustibles to the fire ignition

source

- Configuration of the secondary combustible.

* Example problem on step 4

Joint Fft Plm Co-rSen.t 8 N-o, 2008

Modulef STa l . Detailed Fire Modeling & Single s A COoO../of US. NRC 0/te oNuc/e. R.OA./oO.

Cotn/oonent Fire = d.s /&c A

Slide 8 Notes:

Module 11-10: PROCESS

Identify/Characterize Target Sets

Each target set should be a subset of the fire PRA components and

circuits (i.e., cables) present in the compartment.

- Target sets associated to PRA components can be identified by examining the associated CCDP.

- Those subgroups with very small CCDP may be ignored as insignificant

contributors to fire risk.

- Check for possibility of spurious actuations due to cable fires inside the

compartment under analysis. Spurious actuations may generate the need of

evaluating important scenarios.

Fire modeling should have information on target location within the

compartment available.

- If complete routing information is not available, the analyst must justify target selection process and the corresponding impacts in the Fire PRA model.

- Routing by exclusion OK (from a compartment, from a set of raceways...)

* Identify failure modes of equipment due to fire damage to the equipment or associated circuits.

* Example problem on Step 5

JOint Fin PRA Cours, Se. p ftN. 2008 A Co -o d U.S NRC Omw & Nuw RegW-a Module IMI Task 11a - Dfetled F"o Modeling & Single R.-A (RES) 6 c - h 1-- EPR/

ComparOre-nt Fle Scenarios

2-135
SModule 11-10: PRO( Select Fire Scenarios

Fire scenarios should t

- Selected scenarios sho

case impacting the corn

- Selected scenarios sho

that are important to the

- Selected scenarios sho

e.g., scenarios that cha

- The list of postulated fir.

fixed and transient igniti

Joit Fre PRA Coure, SepL & No- 2008

ModiaM X. Trsk 11. - DO/Md Rn Modeing &S

Conp~aaMdt e ObaMdos

Slide 9 Notes:

CESS

ake the following into consideration:

uld reflect the objective of fire modeling, in this

ponents and circuits of interest to safety

uld represent a complete set of fire conditions

objective

uld challenge the conditions being estimated,

Ilenge habitability if manual action is of interest

a scenarios should include those involving

on sources

rnf j~_9 A C -O~O,,L I -C 0-0 NCMI O~O InaaR.-o/ (nEn) .Elafrt P .,or 00800* (eF80•

Slide 10 Notes:

SModule 11-10: PROCESS Select Fire Scenarios (cont'd)

Approach to selection of fire scenarios is highly dependent on fire

compartment hazard profile, i.e., location and amount of fire source and

combustibles and the location and number of potential targets. In

general,

- In compartment with few fire source and many target sets (e.g., a switchgear

room), start with an ignition source, postulate potential growth and

propagation to other combustibles and postulate damage to the closest target

set that may be exposed to the specific fire

- In compartments with many fire sources and few potential targets (e.g., a

PWR turbine building), start with potential target sets

- In compartments with many fire sources and many potential target (e.g., a

PWR auxiliary building),

Close source/target combinations, and

* Always include that fire scenario most likely (all factors considered) to cause widespread damage (may be driven by fire source characteristics, fire spread potential, or by fire protection systems and features)

Workshop problem 11a-04

Joint Fim PRA Cou-, SpL & ftv. 2008 __ __ A ab ~sonc- NR O wS wc obeoy

Module. fi: Task 11, - DOatMO4 Rm Modaling & Sing/a Sd (RaS) & 6OC- ot Ra fte- aI-stute (EPRO

Comarbant Rn srnio.

2-136
Slide 11 Notes:

! Module 11-10: PROCESS Conduct Fire Growth and Propagation

- Select fire modeling tool depending on the characteristics of

each scenario

- Empirical rule sets

- Hand calculations

- Zone models

- Field models

- Analyze fire growth and spread to secondary combustibles

* Estimate resulting environmental conditions

* Estimate time to target set damage

* Workshop problem 1 la-05 to 1 la-08

W• •rA, PRA C-., SWL A & NOv ý 2M 2008 * A uCaa US 20CtýWc k.Rq..tcy

-snt It. RSSM (RU) SC~t SILIAd.nt&SPR

2-137
Slide 12

Module 11-10: PROCESS

Hand Caics - NUREG 1805

02.1 TemperatureNV.xls

02.2_TemperatureFV.xls

02.3_TemperatureCC.xls

03_H RRFlameHeightBurningDurationCalculation.xls

04_FlameHeightCalculations.xls

05.1_HeatFluxCalculationsWindFree.xls

05.2_HeatFluxCalculationsWind.xls

05.3_ThermalRadiation_From Hyd roca rbonFi reballs.xls

06_IgnitionTimeCalculations.xls 09 Plume TemperatureCalculations.xls

07_Cable_H RRCalculations.xls 10_DetectorActivationTime.xls

08_BurningDurationSoild.xls 13_Compartment_ FlashoverCalculations.xls

09_PlumeTemperatureCalculations.xls 14_CompartmentOverPressureCalculations.xls

15_ExplosionClaculations.xls

16_BatteryRoomFlammableGas Conc.xls

17.1_FRBeamsColumnsSubstitutionCorrelation.xls

17.2_FRBeamsColumnsQuasiSteadyStateSpraylnsulated.xls

17.3_FRBeamsColumns_QuasiSteadyStateBoard_lnsulated.xls

17.4_FRBeamsColumnsQuasiSteadyStateUninsulated.xls

18_VisibilityThroughSmoke.xls

Joint Fire PRA Course, Sept. & Nov. 2008 . A Collaboration of U.S. NRC Office of Nuclear Regulatory

Module I1: Task 1la - Detailed Fire Modeling & Single LSli.de .12 Research (RES) & Electric Power Research Institute (EPRI)

Compartment Fire Scenarios

Notes:

2-138
Slide 13 IModule 11-10: PROCESS

Hand Caics - NUREG 1805

LAYER EIrNT A ROOM FRE WSH NATURAL VII.AT1ON

CO•M•PARG Rr wnE TIEISALLY TYUCKEPT* MOUNARIDS

I-R

Joint Fire PRA Course, Sept. & Nov. 2008

Module /ill Task Ila - Detailed Fire Modeling & Single

Compartment Fire Scenarios

Slide13 A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-139
Slide 14 Notes:

! Module 11-10: PROCESS Hand Calcs - FIVE-Revl

* More than ten years after FIVE, most of the equations are still

considered "State-of-the-Art"

* A revision of the quantitative fire hazard techniques in FIVE

* Most of the hand calculations in the original EPRI publication and

some other models available in the fire protection engineering

literature

- 4 stage heat release rate profile based on t2 growth

- Heskestad's flame height.model

A radiation model from a cylindrical flame to targets

- Models for velocity of plume and ceiling jet flows

- Model for plume diameter as a function of height

- MQH model for room temperature

- Model for visibility through smoke

JO"nt Fkl PRA Cou, , SeP.. & N.v, 2008 A CAIoon o US NRC OONuCR& RbOu/tO~

Mdufle IN: Task 11 - Detid Fir Modeing & Sing.l ReunN ORES) & Be00CC P0. ReOl0 00t0* rEPRO)

Co-Wmfrtna FPn S.H.0

2-140
Slide 15

Notes:

2-141
Slide 16

Notes:

2-142
Slide 17

Notes:

2-143
Slide 18

Notes:

2-144
Slide 19 Notes:

! Module 11-10: PROCESS Fire Detection/Suppression Analysis

* Assess fire detection timing

* Assess timing, reliability, and effectiveness of fixed-fire suppression

systems

* Assess manual fire brigade response

* Estimate probability of fire suppression as a function of time

* Workshop problem 11 a-09

Jokl FRe PRA Course, SW. & Nov, 2008 U n coea oe doS. ups oSIM.twpopRuaf

ModUoft IS. : 18. .0 .sled RI Noottng Stt* e Sing 1 oe, o fRES) 8 EIOSt• • Roboeht~e FF80

CotMptl.rnt Fto Seneds

Slide 20 Notes:

! Module Calculate 11-10: PROCESS Severity Factor

* The time to target damage, and as a result the non-suppression

probability is a function of the postulated heat release rate

* The severity factor should be calculated in combination with the

non-suppression probability

-Workshop problem 11 a-10, 11 a-11

Joint FR.e PRA Co.e-, Sept. & Nov. 2008WO A o o S. NR O oN , R o Module Teek I: SIf De-stted R, ModPJttg £ Pingle S* (E O S & P StJr o efm Reh olefey

Coepaneot File SC=oatlo

2-145
Slide 21

I Module 11-10: PROCESS

Calculate Fire Scenario Frequency

Severity factor for

scenario k

T

Ak =-Ili,k

Ignition frequency for

scenario k

*SVk ~ns,k

Non-suppression

probability for scenario k

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Joint Fire PRA Course, Sept. & Nov. 2008 .

Module Ill. Task Ila - Detailed Fire Modeling & Single Slde 21..

Compartment Fire Scenarios

Notes:

2-146
Slide 22 Notes:

! Module Document 11-10: Analysis PROCESS Results

- The first tier documentation should be sufficient in detail to

allow for an independent reader to understand

- Scenarios postulated, the basis for their selection and analysis,

- The tools utilized in the analysis and basis for selection,

- The final results of the analysis

* The second tier documentation should provide the details

of each individual analysis performed including:

- Details of scenario selection process,

- The fire modeling analyses performed

* All specific considerations and assumptions should be

recorded clearly.

Jokt Rm PPA Co-n. SPt S Nov. 2ft, 0 A C - & U0& N8 O I

ModUo 0: Task 11, - hd Mf ý m M2W 0 & Snge o•o0 4SESE0RCO d • rl 1 , o0

CmPsFl S,

2-147
Session 8: Detection and Suppression

2-148
Slide 1 Notes:

c*U.SNRC ELEOTRIC POW11

EPSIEEARMI ISEITUT1

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module II: Detection and Suppression

Appendix P

Joint RES/EPRI Fire PRA Course

September and November 2008

Bethesda, MD

A Colleborstion of U.S. NRC Office of NuclearRegulatory Research (RES)& EecJtc Poower Research Institute (EPRO

Slide 2 Notes:

D Objectives ETECTION & SUPPRESSION

The objectives of this module are:

* Describe the process for calculation the non-suppression

probability

* Describe the assumptions underlying the recommended

approach for determining the non-suppression probability.

Joint Fire PRA Course, Sept & No, 2008 Slid. Cl01,, 5 of UIS. NIRC 0n,0 of Nfu• Rsgdil.oy

Modul Is: Detection and Soppnsslon Appendx P Res-th (RES) 4 •£5000 pOwer Rw - eh Xntn- dX)PRO

2-149
Slide 3 Notes:

g DETECTION Generalities & SUPPRESSION

State of the art fire models do not have the capabilities of

modeling the effects of all the different fire detection and

suppression strategies available in NPP fire scenarios.

* Time to target damage and non suppression probabilities

are independent calculations

* The time to target damage is an input to the

detection/suppression analysis

JoiM RF. PRA Co•o. Sept & Nov 2008 E Ct] 40 (RES) A Vedn0 P o- NIear -e (toP

Mýdle P: OM .ct end Sopp I..on Appendix P R lRS 48000 Power R hSte (8,R8)

Slide 4 Notes:

! DETECTION & SUPPRESSION Crediting a Fire Det or Supp System

Detection and suppression systems can be credited in the

fire PRA if they are effective and available

* Effectiveness - Will the system detect/control the fire?

- Designed, installed and maintained according to the code of record

and fire protection engineering judgment

- Based on the specific characteristics of the postulated fire scenario

* Available - Probability of the system operating upon

demand

Joint Fire PRA CnoreC, Sept & Nov. 2008 S A CoWlboi-on a0 U.S NRC OCice od Nue Rngauo ry

Module IN. Detection end Suppression Appendix P R_ h ("'5S) - C-fl Poer e0•0 - h teO (-R0)

2-150
Slide 5 Notes:

! DETECTION & SUPPRESSION Fire Detection and Suppression Systems

The following fire detection and suppression systems are

considered in the recommended approach:

- Fire Detection

- Prompt detection

- Automatic detection

- Delayed detection

* Fire Suppression

- Prompt suppression

- Automatic suppression

- Manually actuated fixed suppression

- Manual suppression

JOInR Fie PRA Coon. Sopt A No. 20W 8 A C of U S NRC 050. ofN(dr R I)a•

UM IN, DeONCIon ad Suppý on Appendix P RC~i EROS) & 000.0 R*rth 00(0* (PR04

2-151
Slide 6

! DETECTION & SUPPRESSION Detection-Suppression Event Tree

F1 PQ FS AD AS MD En d8

A OK

a 0OK

C OK<

D OK<

E NS

F OK P, =E+I+M+N

0 OK<

4 0OK

I NS

J 01

K OK

U NS

Joint Fire PRA Course, Sept & Nov. 2008 Slide 6 A Collaboration of U.S. NRC Office of Nuclear Regulatory

Module Ill : ... ,....... A ndix P Research (RES) & Electric Power Research Institute (EPRI) -#If, Vý

Notes:

2-152
Slide 7

IgDETECTION & SUPPRESSION

Detection-Suppression Event Tree

Sequence Detection Suppression

A Prompt detection by Prompt suppression

B * Coniunous fire watch Fire suppression by an automaticall, acuated fixed system

C - Contnuously occupied Fire suppression by a manually acmated fixed system

D 9 High sensitivity detectors Fire suppression by the fire brigade

E Fire damage to target items

F Automatic detection by Fire nuppression by an automatica•ly actuated fixed system

G * Heat detectors Fire suppression by a manually actuated fixed system

H * Smoke deteetors Fire suppression by the fire brigade.

I Fire damage to target items

j Delayed detection by Fire suppression by an automatically actuated fixed system

K * Rosntg fire watch Fire suppression by a manually actuated fxed sýstem

L * Control room verification Fire suppression by the fire brigade

M Fire damage to target items

N Fire. damaae to te, items

Joint Fire PRA Course, Sept & Nov. 2008

Module ii1: Detection and Suppression Appendix P r Slide 7 A Collaboration of U.S. NRC Office of Nuclear Regulatory ....... I Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-153
Slide 8 Notes:

! DETECTION & SUPPRESSION Prompt Detection and Suppression

" Prompt detection

- Assume 1.0 if a continuous fire watch is credited or in-cabinet

detection is available for fires postulated inside cabinets

- Justify the use of 1.0 if an incipient fire detection system is available

- Assume 0 if automatic or delayed detection only are credited

" Prompt suppression

- Credit prompt suppression in hot work fire scenarios

- Probability is obtained from the welding suppression curve

Joint RMe PRA Cows. Spt & Noe. 2008 A * Cooaton oU S NRC 0,•05 oNCOO'R500lO1Y

MoulelU Detm ion ad Svupp fon Apendlx P 5 h ( WS) 5 & -i ft ResMai - 1.10- 105. (FRI)

Slide 9 Notes:

I DETECTION & SUPPRESSION Automatic Detection and Suppression

* Automatic detection

- Assume a probability of failure no larger than 0.05. This the

unreliability for halon systems reported in NSAC 179L.

- Check for availability!

-Automatic suppression (from NSAC 179L)

- Halon systems = 0.05

- CO 2 systems = 0.04

- Wet pipe sprinklers = 0.02

- Deluge or pre-action = 0.05

- Check for availability!

Joint Fin PRA Conse, Sept & Nw. dOSS A COlflanomaIonf U.S. NRC Ofin NdlS r Reud.aoV

Module Ii DOefection -nd Suppnssnon Appendix P (REh SRS) & Elet-c Pner Rns•wh 1--05 (EPRI)

2-154
Slide 10 Notes:

DETECTION & SUPPRESSION

Delayed Detection and Suppression

Delayed detection

- Assume 1.0 - All fires will eventually be detected

- Compare time to target damage Vs time to detection and

suppression

Delayed suppression

- Probability of fire brigade suppression is obtained from the

suppression curves

- Manual actuation of fixed fire suppression systems should include

human reliability analysis.

JoAnt Ft. PRA Co-rs. Sapt a Nov., 2008 A Cdboa mofi SOS. NRC Offa. o0NW ft.ORegatoy

M.d IN: DlofBtf.o0 and Suppmnoslon App-na P 0.00.0 (RES) A EýSC P -Ow 1-0410• (EPR0

Slide 11 Notes:

! DETECTION Detection -'Related & SUPPRESSION FAQ

FAQ 08-0046 Incipient Detection (Status: Open)

- Issue:

* Methodology provides no approach for crediting incipient fire detection

systems

- General approach to resolution:

. Develop an approach that would credit these systems

- Status:

* Initial drafts of a proposed approach are under discussion within the

RES/EPRI teams

* Work continues to try to establish a firm technical basis

* NRC staff and industry review pending

JoInt FI PRA Coors. Sept & Nv. 200W8 b A 000a0,00., w- °u 5 NOV Ora' Nu.o OesdflY " 

Modl. I[H: D5.Ndon and SuppmeIon AppndixP P.0e0,0 (OSS 0 80db Pow0 R.0000h 000ut (FFR0

2-155
! DETECTION & SUI Suppression Curv

The suppression curves 1/1/81

- Developed with the "sup

time was not available, t

* Data do not include sup

automatic systems, and

* Do not include time to d

Io Fl,1 MA C- S.A A Nov. 28 U~odAM lt: OftlcUon a.nd Snppqmlro tnd

Slide 12 Notes:

PPRESSION

es

were developed using FEDB data after

pression time" field. If the suppression

:he "duration" field was used.

ervised burn-outs, fires suppressed with

self-extinguished fires.

etection or fire brigade response.

Slide 13 A r SRC NoteNs:flSV

Slide 13 Notes:

! DETECTION Suppression & Curves SUPPRESSION - Related FAQ

FAQ 08-0050 Fire Brigade Response (Status: Open)

- Issue:

* The fire non-suppression curves as cited as reflecting suppression

performance afterfire brigade response time but a significant fraction of

the duration data used in curves includes brigade response time

* Fire brigade may not be getting adequate credit for suppressing fires prior

to damage

- General approach to resolution:

* EPRI team has reviewed data and proposed an alternative set of nonsuppression curves that would include fire brigade response time

- Status:

* Work to date has largely been confined to EPRI team

* NRC team is currently reviewing proposed resolution

* Staff and industry reviews pending

JointflPRA CouMe, Sept & Nov. 2008 i i A Ca•hmien U.S NRC Offi of 2N2pR.Sy

Modu.e IN: D.e-d.on and Suppmlon Appendix P P0s'th (RES) ,00Stc PP R005' "Sýt't IEPRI)

2-156
Slide 14 Notes:

! DETECTION Selection of Suppression & SUPPRESSION Curves

The suppression curve should be selected based on the type of

postulated fire.

* For prompt suppression by a welding fire watch, use the.

welding suppression curve

* If the fire watch is not successful, an appropriate suppression

curve should be selected depending on the combustibles

ignited due to hot work activities.

Jt/r P PRA Co-sn% Rapt S Nay. M- 1008 .R S/A. 1 A CAot gUS. NRC O& ap.R

Mn W.- De conand Suppatasson Appendix P -s.,rh (RES) & ElARC Powa R n~t/u. fU5 (EPR)

2-157
Slide 15

Notes:

2-158
Slide 16

Notes:

2-159
Slide 17

DETECTION & SUPPRESSION

Suppression Curves

P~e-Adam

5lb 5Ih 9th

Suppression curve Mean50

Percentile Percentile Percentile

T/G fires 21 749 0.03 0.02 0.03 0.04

Control room 6 18 0.33 0.15 0.32 0.58

PWR containment 3 23 0.13 0.04 0.12 0.27

Outdoor transformers 14 373 0.04 0.02 0.04 0.06

Flammable gas 5 195 0.03 0.01 0.02 0.05

Oil fires 36 404 0.09 0.07 0.09 0.11

Cable fires 5 21 0.24 0.09 0.22 0.44

Electrical fires 114 942 0.12 0.10 0.12 0.14

Welding fires 19 99 0.19 0.13 0.19 0.27

Transient fires 24 199 0.12 0.08 0.12 0.16

High energy arcing faults 3 239 0.01 0.00 0.01 0.03

All fires 250 3260 0.08 0.07 0.08 0.08

Joint Fire PRA Course, Sept & Nov. 2008 Slide 17

Module I01 Detection and Suppression Appendix P ............. .

A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-160
Slide 18 Notes:

! DETECTION & SUPPRESSION Dependencies

The following dependencies in suppression analysis could

be important:

* Between automatic detection and suppression

- Example: control panel for a gaseous suppression system

* Between actuated barriers and fire suppression systems

* Between safe shutdown capabilities and automatic

suppression

- Example: crediting fire fighting water for core injection, heat removal

or secondary heat removal

* Between manual and automatic suppression

Moent FPRA Ctinse. SVppss on. 2000 A Ch OR S. C P 00100 o &ROe A Onop

ModalIf. etilDfCon and Slupplon loAppofldloP Li 1] Re-oiv (RESi & Ehaft Pý, R--e., - (EPR4.0

Slide 19 Notes:

DETECTION & SUPPRESSION

Example

The scenario consists of an MCC fire affecting a target in the

hot gas layer.

* The room is equipped with a smoke detection system and a

manually activated fire suppression system

* Using fire modeling

- Time to smoke detection = 1 min

- Time to target damage = 15 min

* From fire drill records and/or plant procedures

- Brigade response time = 7 min

- Time to manually actuate the suppression system will not be less

than 10 min

- Time to delayed detection assumed to be 15 min

Jont Rm PRA Course, SoPE & No.2000 A CdlaloOtOn of U, NRC 0ffieo N2R8 ReuatOy

Module 0g: DeOec/on and Suppession Appendix P Rei¢h lOES) £0030 Po Re$Orh Intitut (ERR)

2-161
Slide 20

Notes:

2-162
Slide 21 Notes:

SDETECTION & SUPPRESSION Concluding Remarks

The non-suppression probability is credited in Task 11,

detailed fire modeling

* Target damage is evaluated assuming no

detection/suppression capabilities in the room

* The time to target damage is an input to the detection and

suppression analysis.

* The recommended approach includes an event tree

capturing prompt, automatic, and delayed detection and

suppression capabilities

* The event tree may need to be modified depending on the

scenario

Joint RF PRA Co,,• SWL & Nov- 208 S-; 21 A CO-IO,&&.° US . NR ulrl aty

Modo AN, DeKtoon and Suwpowion Appende P RP -t- (RES) & -Eýto Powerth Ins. UteM (EPR-)

2-163
Session 9: Special Fire Models Part 1

2-164
Slide 1 Notes:

MU.S.NRC

nc srd

EUCTRIC POWER E17ralu RESEARCH 91511TWlt

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module III: Task 11, Special Fire Models

Part I

Joint RES/EPRI Fire PRA Course

September and November 2008

Bethesda, MD

A Collaboration of U.S. NRC Office of Nuoler Regulatory Research (RES) & Electfic Power Research Institute (EPRO

Slide 2 Notes:

FIRE MODELS

* Generally computational fire models are developed to

estimate extent and timing of fire growth

* There are fire scenarios critical to NPP applications that

are beyond capability of existing computational fire

models

- Special models are developed for prediction of consequences of

such scenarios, based on a combination of:

* Fire experiments,

* Operating experience, actual fire events

* Engineering judgment

Joint Fire PRA Cou-e, Sept & Nov. 2008 A I olUS. IOostlon -RC Of-iv If Nu, Regulatoly

Module I0: Task 11, Speolal Fire Models PSrt 1 osf (-ES) &.85r P ower R ,h s 5 (CR0Q

2-165
Slide 3 Notes:

Th

! SPECIAL MODELS

* Cable fires (modified from IPEEE approaches)

- Cable spreading room and cable tunnel fire risk

* High energy arcing faults (new)

- Switchgear room

Fire propagation to adjacent cabinets (consolidation)

- Relay room

* Passive fire protection features (consolidation)

JObf Fkv PRA Cowfl, SWt. A NOV. 2008 s A 0o ,A d U S. NRC Ot%" SN V

MUOCA, W.n I: i1. Spec

tm2

Pb ModWS Pft"f ReSh (OOS) ( & a EI S wnec #• fEPR

Slide 4 Notes:

SPECIAL MODELS (Part 2)

" Main control board (new)

* Hydrogen fires (new)

" Turbine generator fires (new)

" Smoke damage (consolidation of research - new

risk analysis guidance)

Joint Fir PRA CO-e, S. pL & N-5. 2008 s A CoUaboRl of U SNC Of. On N AW orV

Moý18e o.. Tas 11, Spec1al FIn Models P-rh Fs RI (IRES) & OeS PoIeVResearch Inst8,Ae lePRf

2-166
Slide 5 Notes:

! CABLE FIRES (1 of 9)

* No generalized analytical theory is available to accurately

model cable fires in all possible configurations in

commercial nuclear plants.

* Most of the information compiled for this appendix is in the

form of flammability parameters derived from experiments or

correlations also developed from experimental data.

* The amount of experimental evidence and analytical tools

available to model cable tray fires is relatively small when

compared to the vast number of possible fire scenarios that

can be postulated for NPPs

* Simplification of these scenarios will be needed

Joint FmD PRA Co s, Sept. & Nov. 2008 S A Cooý mtoin od US. N R Off" . O Nfle R e oy

Mode SI: in s ? 1. Speci1 S.1 Model. pa r I R-s.h (RES) &E/m 6t04o0 80 hant-ýt.- (-pm)

Slide 6 Notes:

! CABLE FIRES (2 of 9)

Scenarios involving cable fires may start as:

Self-ignited cable fires

- Postulate self ignited cable fires in unqualified cables only

- Self ignited cable fires should be characterized by a cable mass ratio

(mass of cables in the room / mass of cables in the plant)

representative of the scenario.

- Cable mass ratio is equivalent to the severity factor

Or as secondary fires caused by fixed or transient fire

sources

- Cable fires caused by welding & cutting should be postulated in both

qualified and unqualified cables.

Joint F.m PR8 Cor.-, Sept Nov.208 20b0008 p A oP.S, 0R0 OffioNut•wM l eA 

Madule Ifl: Task 11, Special Fire Modets Pt I R-seah (RES) & B- 1550 PA 8r c 8.4. (EPRI)

2-167
Slide 7

Notes:

2-168
Slide 8

! CABLE FIRES (4 of 9)

Heat release rate from cable

fires

* qbs: bench scale heat release

rate per unit area

- A: burning area

-Length of the ignition source

times tray width

Joint Fire PRA Course, Sept. & Nov. 2008 Slide

Module /i. Task 11, Special Fire Models Part I ..................

Q , :- 0. 4 5 q . bs • A

Bench Scale HRR Values Under a Heat Flux of 60 kWlm2

,

Material Bench Scale HRR

Material__ [kWnl']

XPEI/FRXPE 475

XPEtNeoprene 354

XPE/Neoprene 302

XPE/XPE 178

PEIPVC 395

PE/PVC 359

PE/PVC 312

PEJPVC 589

PE, NylonlPVC. Nylon 231

PE, Nylon/PVC. Nylon 218

A Collaboration of U.S. NRC Office of Nuclear Regulatory 8 ....... RResearch (RES) & Electric Power Research Institute (EPRI)

Notes:

2-169
Slide 9

Notes:

2-170
Slide 10

I CABLE FIRES (6 of 9)

Flame spread model

e Vertical trays

- 6 is assumed to be 2 mm

- q" is assumed as 25 kW/m 2

" Horizontal trays

- 6 is assumed to be zf

- q" is assumed as 70 kW/m 2

Joint Fire PRA Course, Sept & Nov. 2008

Module It., Task 11, Special Fire Models Part I

4(4 6 9 2 

iz(kPXT _g Tom

Cable tray

Zf

xp

de A Collaboration of U S. NRC Office of Nuclear Regulatory ... 0 Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-171
Slide 11 Notes:

CABLE FIRES (7 of 9)

Example

Material properties

PVC cables:

- K =0.000192 kW/m K

- p =1380 kg/m3

- Cp = 1.289 kJ/kg K

-Tg = 218'C

- XPE cables: - K = 0.000235 kW/m K

- p = 1375 kg/m3

- C = 1.390 kJ/kg K

Tip= 3300C

"tA F" PRA Ga-e Swp a ft, Z"0 A-6 A Cd- O00 0 RCTA .,e00

MA N.- 0.5 11, 3peed Pý Moýt ~ft7 I I L - ,0 rw RS £ 0.00 000 0.000 0 0 fRXl9

Slide 12 Notes:

I CABLE FIRES (8 of 9)

Example

- Horizontal trays

- Flame spread for XPLE cable = 0.3

mm/sec (-0.05'/min)

- Flame spread for PVC cable = 0.9

mm/sec (-0.2'/min)

Joknt Fne PRA Co-rt0 SSpt0 & ft, 2M0 .

Module X. le: to f, SpeaT RModels Po? _(

ACýýa 'S Ný ý ýNý RýdWý

2-172
Slide 13

I CABLE FIRES (9 of 9)

Example

" Vertical spread in cables

" PE/PVC cables

Batch Sca HRR Flo gspd Rnae -ra

Materil [kV1 rate [mm a] rate [ft~UWn

PEVC 395 156 31

PVETC 359 137 27

F.PVC 312 112 22

psVC 589 251 52

* The heat release rate for XPE cable is

178 kW/m 2 . Using these inputs, the

estimated flame spread is 11 mm/sec

(2 ft/min)

Joint Fire PRA Course, Sept. & Nov. 2008 Slie 13 A Col

Module It. Task 11, Special Fire Models Part I ; ............. . Rese

I

laboration of U.S. NRC Office of Nuclear Regulatory

arch (RES) & Electric Power Research Institute (EPRI)

Notes:

2-173
Slide 14

I FIRE PROPAGATION IN CABLE TRAY

WITH RG 1.75 SEPARATION (1 of 2)

STACKS

35 0

35o/

n=3

n=2

n= 1 ill"

'I

/

kCable tray stack

Ignition Source

Characteristic length

Ln,1 = Ln +2(hn,+iTan(350))

Joint Fire PRA Course, Sept. & Nov. 2008

Module II: Task 11, Special Fire Models Part I

idel4-- A Collaboration of U.S. NRC Office of Nuclear Regulatory

[-.................i Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-174
Slide 15 Notes:

FIRE PROPAGATION IN CABLE TRAY STACKS WITH RG 1.75 SEPARATION (2 OF 2)

* First tray to second tray: 4 minutes after ignition of first tray

* Second tray to third tray: 3 minutes after ignition of second

first tray

* Third tray to fourth tray: 2 minutes after ignition of third tray

* Fourth tray to fifth tray: 1 minute after ignition of fourth tray

* Balance of trays in stack: 1 minute after ignition of fifth tray

Joint Fft PP. Cous., S•w•. Not ft, 2008 A CobboOtkfl U0 U NRC flwt.&ORg•htov

Modutit tmt T.St 1, ,tn t RPOD Uodes Pit I R ot E S) & Ek N R- 40• (E4 CPR0

Slide 16 Notes:

WITH FIRE PROPAGATION IN CABLE TRAY STACKS RG 1.75 SEPARATION (2 OF 2) (cont'd)

* If there is a second stack of cable trays next to the first

stack, spread to the first (lowest) tray in the second stack will

be assumed to occur concurrent with spread of fire to the

third tray in the original stack.

* Subsequent spread of fire in the second stack will mimic the

continued growth of fire in the first stack (e.g., the second

tray in the second stack will ignite within 2 minutes of the

first tray in the second stack - at the same time as the fourth

tray in the first stack.)

* Fire spread will occur at the same rate to stacks on either or

both sides of the original stack

Jnd Fim PRA Cou-, Sept. & Nov. 2008 0 A CoabnrfltVC NRC ORin. OtNnCtar Rgtov

Modutt. tle, Tas 1.80 Speciat Fire Modets Ptra i ROeo0 (RES) & Ctns PoE- , R0.-.. -tate EpR00

2-175
Slide 17 Notes:

F Related IRE PROPAGATION FAQ IN CABLE TRAY STACKS

FAQ 08-0049 (Status: Open)

- Issue:

* The cable fire empirical spread model (tray-to-tray, stack-to-stack) has

been misapplied in pilot applications

* Reviewers concluded that misapplication resulted in very conservative

fire growth and risk results

- General approach to resolution:

. Clarify the bounds of the empirical model to avoid misapplication

- Status:

* Proposed resolution has recently completed final review within the RES

and EPRI teams

* Staff and industry final review pending

* Final revision, as needed, pending

- Note: as a follow-on, team plans to generate a new FAQ to address

broader needs relative to cable fire growth modeling

JOwt Ff PRA Cou, SPt & No. 2008 L S • U O5.egu5go,

Mod.le 1X Task 11, Spfcttnwft Modet PII ' (SOS) S P008 00n 08 h SA (EFS)

Slide 18 Notes:

HIGH ENERGY ARCING FAULTS (1 of 16)

Definition

- Rapid release of electrical energy in the form of heat,

vaporized copper, and mechanical force.

-An arc is a very intense discharge of electrons between two

electrodes that are carrying an electric current. The arc is

created by the flow of electrons through charged particles of

gas ions that exist as a result of vaporization of the

conductive material.

Joint Fi, PRA Course. Sopt, & No, 2008 S A 080abo00,n oA U. NRC Off. oNL080eguAtor

MduAe 111, Task 11. Sp-cal IM, Modes Pont I R h (RES) & B0ct50 PoeW pRe h IIsI~o (EPRI)

2-176
Slide 19 Notes:

! HIGH ENERGY ARCING FAULTS (2 of 16)

Scope

* Switchgears

* Load centers

* Bus bars

More than 440 V

* Oil filled outdoor transformers are addressed separately

Jomt Fft PRA Co-s. Sept. 4M. 208 ; •S A CO_19-O] -S N- OffisW. M -ROV Aoy Uod015 ID: Thtl.• Sp cM! F#n ModelS PaflI Rester tRES) & 85045 Rean, 0.0.0 050. lEPRS

Slide 20 Notes:

! HIGH ENERGY ARCING FAULTS (3 of 16)

General characteristics of HEAF events (from FEDB)

* Indications of heavy smoke in the area, which may delay

identification of the fire origin and whether the fire is still

burning.

* In nearly all of these events, the HEAF initiates in the feed

breaker cubicle. This is because this is where most of the

electrical energy in a high-energy cabinet resides.

* HEAFs occurring in 480V switchgears did not report

damage beyond the switchgear itself, but some resulted in

the cabinet opening.

Joinl Fime PRO Co-s, Sept & Nov. 2W80 A Cdlsbo , f S. NOV of Nucl Re00t05

Module 10h Task 11, Special F Models Part1 I Rear (RFS) 05045 P0.,r R 0r1h IruEPRO"

2-177
HIGH ENERGY AR

General characteristics

* Initial use of fire extin

HEAF events regard]

Halon, or dry chemica

suppressed with wate

* No conclusions can b

fixed fire suppression

one event was succe

Halon system.

* Durations of the fires

over an hour. The sh

* that do not result in la

device itself or extern

"I tR. PRA Co- St. d 18ov. f 008

Modul. I: T7.k 11, Specb Flý Modes Pan

Slide 21 Notes:

CING FAULTS (4 of 16)

of HEAF events (from FEDB)

guishers may be ineffective in severe

ess of the extinguishing agent (C02,

al). The fires were eventually

r by the fire brigade.

e made regarding the effectiveness of

systems for the ensuing fire. Only

ssfully suppressed with an automatic

involving HEAF range from minutes to

ort durations generally reflect events

Irge ensuing fire(s), either in the

al fires.

RE-:=2t (R-ES) & 8.0•0c Power Rh i4.14- (EPRI)

Slide 22 Notes:

HIGH ENERGY ARCING FAULTS (5 of 16)

General characteristics of HEAF events (from FEDB)

* Sustained fires after the initial HEAF involve combustible

materials (cable insulation, for the most part) near the

cabinet.

* Damage may extend to cables and cabinets in the vicinity of

the high-energy electrical cabinet.

* Damage to cabinet internals and nearby equipment (if

observed) appears to occur relatively early in the event.

Joint Fite PRA Co, St. & V.0 2008.0 A C00• 0 &0.2 U.0058 S., NRC OfOfC a ofNler Rnogu ty

Module IN, TaSk 11, SpeciFla Models Part Re5=h 0 (RES) d E-e P R.- 85 Int (EPR0

2-178
HIGH ENERGY AR

The arcing or energetic

devices consists of two

damage characteristics

and effectiveness.

- The first phase is a sh

followed by ensuing fir

device itself, as well a:

such as overhead exp

that may be ignited du

Jownl Fn, PRA Coco., Sept. & •o. 2W00

ModuM : Tsk 11, Specj /R Modýt PInt

Slide 23 Notes:

CING FAULTS (6 of 16)

fault scenario in these electrical

distinct phases, each with its own and detection/suppression response

ort, rapid release of electrical energy

*e(s) that may involve the electrical

s any external exposed combustibles,

osed cable trays or nearby panels,

ring the energetic phase.

Af M NRzOr ,()s 

Slide 24 Notes:

! HIGH ENERGY ARCING FAULTS (6 of 16) (contd)

The second phase, i.e., the ensuing fire(s), is treated similar

to electrical cabinet fires described else where in this

procedure, with one distinction. Any closed electrical cabinet

subject to a HEAF is opened to a fully ventilated fire. In

dealing with postulated switchgear and load center fires,

both phases should be considered.

Joint Fire PRA Cou-, Sept, & NOV. 2008 S A C",aOO a o S. NRC Stks oa Nkt" RePtata

Modut W.t: Task 11, Special Fit MOdets p35 (-) IRES & 0000 - Po ,-sear O•att SPOt

2-179
Slide 25

HIGH ENERGY ARCING FAt

The zone of influence

Joint Fire PRA Course, Sept & Nov. 2008 IS 2

Module III: Task 11, Special Fire Models Part I ..

Notes:

2-180
Slide 26 Notes:

HIGH ENERGY ARCING FAULTS (8 of 16)

High-Energy Phase: The zone of influence

* The initial arcing fault will cause destructive and

unrecoverable failure of the faulting device, e.g., the feeder

breaker cubicle, including the control and bus-bar sections.

* The next upstream over-current protection device in the

* power feed circuit leading to the initially faulting device will

trip open, causing the loss of all components fed by that

electrical bus. This fault may be recoverable if the initial

faulting device can be isolated from the feeder circuit.

* The release of copper plasma and/or mechanical shock will

cause the next directly adjoining/adjacent switchgear or load

center cubicles within the same cabinet bank and in all

directions (above, below, to the sides) to trip open.

J0it Mluft Fk IN, PP.4 T.0 11S Come. I. SPdJ SW.L 0F8'0.* & ftý 2008 ppdf F-___ .

08.0fE)8E 0 orE O .E

Slide 27 Notes:

HIGH ENERGY ARCING FAULTS (9 of 16)

High-Energy Phase: The zone of influence

Any unprotected cables that drop into the top of the panel in

an open air-drop configuration will ignite.

- Cables in conduit or in a fire wrap are considered protected in this

context. In other words, if cables are protected (i.e., not exposed) by

conduit or fire wrap, they are assumed damaged, but not ignited, and

they do not contribute to the fire load.

- Armored cables with an exposed plastic covering are considered

unprotected in this context.

Exposed cables, or other exposed flammable or

combustible materials or transient fuel materials located

within this same region (0.9 m (3) horizontally) will be

ignited.

Joint Fire PRA Coupe, Sept & No,. 2008 ( S A Coho ofU S NRC Office 

0

N8.uatof'

ModuoleU: Task IN , Space. Ff,.Models Part Remh (RES) & eCfA* Pew ReSah I.Wo le (FBoR)

2-181
Slide 28 Notes:

! HIGH ENERGY ARCING FAULTS (10 of 16)

High-Energy Phase: The zone of influence

Any unprotected cables in the first overhead cable tray will be ignited

concurrent with the initial arcing fault provided that this first tray is within

1.5 m (5') vertical distance of the top of the cabinet. The cable tray fire

will propagate to additional trays consistent with the approach provided

for the treatment of cable tray fires elsewhere in this document,

assuming that the time to ignition of the first tray is zero rather than the

normal 5 minutes.

- This applies to any cable tray located directly above the panel.

- This applies to any cable tray above the aisle way directly in front of, or

behind, the faulting cabinet, provided some part of that tray is within 0.3 m

(12") horizontally of the cabinet's front or rear face panel.

- Cables in conduit or in a fire wrap are considered protected in this context.

- Armored cables with an exposed plastic covering are considered

unprotected in this context

JoF Fko PRA C -, Sept. & hOb 2M58 . A A o U S NnC 150 a No Wft• R

Module in: T.ý 11, Spac~m El, Models Per1 -e05 (RES) & d -r - 1 - (•QEPI

Slide 29 Notes:

1 HIGH ENERGY ARCING FAULTS (11 of 16)

High-Energy Phase: The zone of influence

Any vulnerable component or movable/operable structural element located

within 0.9 m (3) horizontally of either the front or rear panels/doors, and at

or below the top of the faulting cabinet section, will suffer physical damage

and functional failure.

- This will include mobile/operable structural elements like fire dampers and fire

doors.

- This will include potentially vulnerable electrical or electromechanical

components such as cables, transformers, ventilation fans, other cabinets, etc.

- This will exclude fixed structural elements such as walls, floors, ceilings, and

intact penetration seals.

- This will exclude large components and purely mechanical components such

as large pumps, valves, major piping, fire sprinkler piping, or other large piping

(1" diameter or greater).

- This may include small oil feed lines, instrument air piping, or other small

piping (less than 1" diameter).

Joint Fmr PRA Co-, Sept. & Nov. 2W58 S A Co-o&•raot oaUS. NRC Ste ,tNý,esrRVUoWy

Modui ID: Task 11, Spcifl Re Models Parn 29 Re1F Oh (RES) &UEl trtc Po R1es1 h ntoiut (EMRI)

2-182
! HIGH ENERGY Al

- In the case of bus du

assumed damaged a

- The entire length of th

- Any cable (damage o immediately adjacent

- Equipment connected

- If there are fire barriei

be credited to limit da

the damage and/or ig

limited to one side of

compartment fire scen

barrier(s).

JON2 Fire PA Cr, Sept. & N-v. 2008

MO&t is.: Co 1, Spmcbl FIte Models Prt

Slide 30 Notes:

RCING FAULTS (12 of 16)

cts, the following equipment should be

nd/or ignited

e bus duct.

r ignition) or combustibles (ignition only)

to the bus duct.

Ito the bus duct.

rs along the length of the bus duct, these can

mage and/or ignition. It may be assumed that

nition from a arcing fault in the bus duct is

the fire barrier, except when analyzing multinarios that account for failure of the fire

S ACOILO Uoo S. NRC Offraldee•r08e,Y

ea (RES) & Eer0o PoweB ft r - ch rte 1- (EP

Slide 31 Notes:

HIGH ENERGY ARCING FAULTS (13 of 16)

Detection and Suppression

* The amount of smoke from any damaging HEAF event

expected to activate any smoke detection system in the

area.

* Manual suppression by plant personnel and the fire brigade

may be credited to control and prevent damage outside the

initial ZOI from ensuing fires.

* Separate suppression curves are developed for these fires

documented in Appendix P to the Fire Modeling procedure.

Jotnl FiP PRA Co-, S. 0

1 Nov. 20W8 Fpýj, A &of U&S NRC OOoNucýeeRý lalog y

Module Ill: Tsk 11, Special Fie Models I Resea S & I Elct C E. oon Ros.sr) -ru- (ER)

2-183
! HIGH ENERGYAR

Modeling HEAF in the

* Identify the equipmen

generated. As indicat

the most part, 4160 V

centers, and bus bars

* Two types of initiating

identified equipment:

- A HEAF event with an

- A regular equipment fir

ot R.e PTA C-,. Sp. ecA M, 2M

ModeM IN, T.0 11, Spýei FR. Me.W. p., I

Slide 32 Notes:

ICING FAULTS (14 of 16)

Fire PRA

t in the room where a HEAF can be

ed earlier, this equipment includes, for

to 440 V switchgear cabinets, load

events should be postulated for each

ensuing fire, and

re (no HEAF).

Slide 33 Notes:

HIGH ENERGY ARCING FAULTS (15 of 16)

Non Suppression Probability and Severity Factors

Assign a generic frequency for HEAFs listed in Task 6, and apportion it

with the location and ignition source weighting factors to the equipment

under analysis.

* Assume targets in the ZOI are damaged at time zero.

* The probability of no manual suppression for the targets in the ZOI is

1.0.

* The severity factor for a scenario consisting of targets in the ZOI only is

1.0.

* Probability of no automatic suppression for targets in the ZOI is 1.0

* The probability of no manual suppression for targets outside the ZOI can be calculated using the detection suppression event tree described

in Appendix P, with the HEAF manual suppression curve.

Joinl Fme PRA C-us, SepL Nov. 2008 s A Cosboet•n 01 U & NRC OffWoiNe d -N ReuatFy

Modet. to: Task 11. Special Fi. Models Pad I Re h (RES) & E oI• ew Reseah -siue (SFRf)

2-184
Slide 34 Notes:

! HIGH ENERGY ARCING FAULTS (16 of 16)

Example

* Consider a HEAF scenario consisting of a switchgear cabinet

affecting two targets. A stack of three cable trays is above the

cabinet. The first tray in the stack is 0.9 m (3') above the cabinet.

It has been determined that one of the targets is in the first tray.

The other target is in the third tray.

* According to the approach provided in Section M.3, the first target

is assumed ignited at the time of the HEAF. The second target is

damaged at time 7 minutes (4 minutes for fire propagation from

the first to the second tray, and 3 minutes for fire propagation

from the second to the third tray).

- A scenario involving target in the first tray CDF, = A, Wý -W. -CCDP,

- A scenario involving the two targets CDF, = Ag -WL -W, -Pý -CCDP,

JoiN R. PRA Co-oe. SWO. & fot. 2008 FS ;o34 0 A 80 U 08C NM W oS R0 oIy

ModeM Is. Task 11, Speci TO. Modal. Ppr IEpRO 8.R.erc (8ES) 8 BE~od Pwer Rlsth 0810t. 

Slide 35 Notes:

F IRE PROPAGATION TO ADJACENT ELECTRICAL CABINETS (1 of 3)

Analytical fire models may be used in all types of fire

propagation and damage scenarios.

* This appendix discusses empirical approaches for

determining:

- Fire propagation to adjacent cabinets

- Fire induced damage in adjacent cabinets

* Empirical approach based on SNL and VTT experiments

Jolt Fm PRO C-n, Sept & Nov.2008 S A COhaosio, oUS. 'uSJO&O NRC OMiM of oy

Modl. IN: Tak 11, Spoeýla Rm MOo s PaH, ReIash (COPS) & El- -o R - 0 , h -,. itut0 (EPR0

2-185
Slide 36 Notes:

FIRE PROPAGATION TO ADJACENT ELECTRICAL CABINETS (2 of 3)

The empirical model for fire propagation consists of the

following rules:

-Assume no fire spread if either:

- Cabinets are separated by a double wall with an air gap, or

- Either the exposed or exposing cabinet has an open top, and there

is an internal wall, possibly with some openings, and there is no

diagonal cable run between the exposing and exposed cabinet.

- If fire spread cannot be ruled out, or cabinets are separated

by a single metal wall, assume that no significant heat

release occurs from the adjacent cabinet for 10 minutes if

cables in the adjacent cabinet are in direct contact with the

separating wall, and 15 minutes if cables are not in contact

with the wall.

Joint FPh PRA Coun' Sept. & Nov2008 A Cf• orahon OS. NRC OStO,0N00R0908,oy

Modue 1,8: T.s. 11, Speotal Fin Moats PFrt 1 1RES) Reserc & p , Re 000h t (PRI

Slide 37 Notes:

FIRE PROPAGATION TO ADJACENT

ELECTRICAL CABINETS (3 of 3)

.The empirical model for fire damage consists of the following rules:

* Assume loss of function in an adjacent cabinet if there is not a double

wall with an air gap.

* Assume no damage in the second adjacent cabinet occurs until after the

fire propagates to the adjacent.cabinet. Assume damage can occur

earlier if there are large openings in a wall and plenum areas in which a

hot gas layer is likely to form.

* Assume no damage to an adjacent cabinet if:

- There is a double wall with an air gap, and - There are no sensitive electronics in the adjacent cabinet (or the sensitive

electronics have been "qualified" above 82oC).

* Assume damage to sensitive electronics occurs at 10 minutes if there is a

double wall with an air gap.

* Assume damage to sensitive electronics can be prevented before 10

minutes if the fire is extinguished and the cabinet is cooled, e.g., by CO 2

extinguishers.

Joint Fm PRA Co , S.pt. & Nov 2008 W8A C oOa J.S. NRC O 00e u O h O,

Mode in, Tr_0 11. Spnho F/n Modes Part h /0ES/0 800* POw. RIfCf /n0tu0 (EpRIa

2-186
Slide 38 Notes:

P! ASSIVE FIRE PROTECTION FEATURES (1 of 6)

Most of the fire protection capabilities of passive fire

protection features cannot be evaluated using analytical fire

modeling tools.

* Empirical approaches

* Limited analytical approaches

* Probabilistic approaches

4Ot Fus PRA Cot,8. Sept. 8 tRA 2008 , 3 A 0082MPol0 20,800o•N, S In Osksol0 R-f1-1

Modulo 10, Teak 11, Sp ecia F?,. Models PFio 8 Reso lO(RES) 8 2•eouk o R 0 - (EPR8

Slide 39 Notes:

! PASSIVE FIRE PROTECTION FEATURES (2 of 6)

Passive fire protection refers to fixed features put in place for

reducing or preventing fire propagation. Some examples are:

* Coatings

* Cable tray barriers Empirical approach

* Fire stops

*Dampers

• Pene tration seals Probabilistic approach

*Doors

Walrs -Limited analytical approach * Walls _

Joint Fes PR A Cou,,re, Sepl, 8 NoA . 2008 S e 8 Cd80abo-in o IS. In0 Oftice o Ncd R -Re ooy

M odule IN: TMsk 11, Sped 1 FIR M odels Pgrt I Re $0 h (RES) & Eletd r Po wer R -o r -ntiut (EPRI)

2-187
Slide 40 Notes:

P (3 ASSIVE of 6) FIRE PROTECTION FEATURES

The analytical approach for modeling the response of passive

fire protection features to fire generated conditions consists of a heat transfer analysis.

* The boundary conditions are the fire generated conditions. In

general, these consist of the heat flux exchanges at the

surface of the passive feature.

- Thermo-physical properties of the material are necessary. These

properties are readily available for some materials like concrete or steel.

* Models can be used for estimating the temperature profile

throughout the thickness of the barrier

* Effects of cracks and gaps in doors or walls can be evaluated

only with the objective of analyzing smoke migration.

Joint UMod. Fft PRA . Se.Met, & N-o 2W08 ES Peale Pen R ,nnaA Nuc l(EPRM ) IN. T.0 11, Sprbt Fi Model Pu I R. •)&• P* • i =R

2-188
Slide 41

! PASSIVE FIRE PROTECTION FEATURES (4 of 6)

The empirical approaches consist of replicating the thermal

response of fire protection features observed in fire tests in the

postulated fire scenarios.

* Coatings: SNL tests

- The cable tray configurations included both a single cable tray and a two-tray

stack. Exposure fires included either a gas burner or a diesel fuel pool fire.

* Assume coated, nonqualified cables will not ignite for at least 12 minutes,

and coated, nonqualified cables will not be damaged for at least 3

minutes for large exposure fires, and for cable tray fires, more likely about

10 minutes... - .. . Coating Time to Ignition (rain) Timn to Darnall. (.in)

Lower Tray Reponse

FlameMtas"t 7A 10 FlameMaster 77 13 0

CaitiSco CIA 12 3

Carbothe In tunaOf 285 No 10

Quelco, 703B 12 11

Upoer Tray Response

FlameMaster7lA No 11

FtmeMaster 77 No I' VasTo CO VIA 12 7

Carsiole Intumastc 285 No 19 OlGoi1 703B 12 11

Joint Fire PRA Course, Sept. & Nov. 2008 Slide 41 A Collaboration of U.S. NRC Office of Nuclear Regulatory

Module Il: Task 11, Special Fire Models Part I . Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-189
Slide 42 Notes:

! PASSIVE FIRE PROTECTION FEATURES (5 of 6)

The empirical approaches consist of replicating the thermal

response of fire protection features observed in fire tests in the

postulated fire scenarios.

* Cable tray barriers and fire stops: SNL tests (same

configuration as coating tests)

* The following systems were tested:

- Ceramic wool blanket wrap, solid tray bottom covers, solid tray top cover with no vents, solid tray bottom cover with vented top cover,

one-inch insulating barrier between cable trays, and fire stops.

* Propagation of the fire to the second tray was prevented in

each case.

Jont Fire PRA Coe. Sept & N-v. 2008 M A Cobe&,on oS. NRC OflP aNNPk•R.guttoV

Module IN: TsA 11. Sp•cId Fim Models Pmrt I 1- Reo h ES) & 000,0 PSe- - f eeh st-- e (ECR8

Slide 43 Notes:

P (5 ASSIVE of 6) (cont'd) FIRE PROTECTION FEATURES

- Barriers seem to substantially delay cable damage for

qualified cable. The barriers did not delay cable damage for

nonqualified cable.

- Results considered most appropriate to exposure fires with

smaller HRR and to cable trays

in a stack threatened by fires in lower trays.

- Each barrier prevents cable tray ignition until well after the fire

brigade reaches the scene

(i.e., greater than 20 minutes),

- Each barrier prevents damage in qualified cable with solid tray

bottom covers until well after the fire brigade reaches the scene.

J&0, Fi, PRA Coun, Sept. A Nov.2008 • A Cot0tooUS. NRC Offi o WN-CIOReuAtICy R 

Moe M.h TR k 11, SpWcWal Pire Mels Per I O (RES) A C R000 P-o7 es 0 .0.0 doteC PRO

2-190
Slide 44 Notes:

PASSIVE FIRE PROTECTION FEATURES

(6 of 6)

Probabilistic modeling of passive fire suppression systems

* Dampers: Equipment unavailability obtained from

inspection results

* Penetration seals: Equipment unavailability obtained from

inspection results

Jo" Fka PRA Co-. SWt. 4N 2008 A C (___ Ua 0S.0 O8 0r RV4 

MUduf It W T,•. IIf 11 Spc FlmModts Parl I,108. R 0rOhES) 8ýc P.S.. EPRO

2-191
Session lOa: Special Fire Models Part 2

2-192
Slide 1 Notes:

CUS.NRC IRiRIC PIW ft EeCH I

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module III Pt. 2: Special Fire Models Part 2

Joint RES/EPRI Fire PRA Workshop

September 2008

Washington DC

A Collboration of U.S. NRC Off-e of Nuclear Regulatory Research (RES) & Electric Power Research Institute (EPRI

Slide 2 Notes:

Module I11-11, Pt. 2: Special Models Part 2 Scope of this Module

Module I11-11, Pt. 2 covers the three remaining "Special

Models"

- Main Control Board Fires (Appendix L)

- Turbine Generator (TG) Set Fires (Appendix 0)

- Hydrogen Fires (Appendix N)

MRo. PR Wonhpac, 200, WasFi gtM o DC 2 Sart R abh Si . NlCtric P O NR , llte )

Module lt/Pt 2: Special Pre Model, Pan!2 2 RESeOf &hS 0 neOO~l 1)521 (- E

2-193
Slide 3 Notes:

! Module I1-11, Pt. 2: Special Models Part 2 Main Control Board Damage Likelihood Model

The main control board (MCB) presents many analysis

challenges

- Design practices vary widely

* Configuration of the boards themselves

* Relay rack room versus main control room

* Separation and partitioning within MCB

- MCB may be important to risk, but IPEEE vintage approaches were

identified as a weakness of those studies

- Fire models cannot currently predict in-panel fire behavior so an

alternative approach is needed

A method is provided to assess the likelihood that a fire in

the MCB will grow large enough to damage a specific target

set as defined by a specific physical region of the board

Fdm PRA WW*W. 2008, M8.dthqs 0CZ ShF" 3 ACb dUS&1 E NR C ffoer tnfat, PRW

Modlh. MD ftZ: SpWcWa 1*1 AfIS Pan! 000 (RES) &E-0U 0000 80000 -~U tEPRO

Slide 4 Notes:

! Module Il1-11, Pt. 2: Special Models Part 2 Main Control Board Damage Likelihood Model

- The MCB model is built on several assumptions that are

specific to the MCB and the MCR

- MCB fire frequency partitioning approach

- Suppression times for MCR fires

- Fire characteristics of a MCR type control panel (peak HRR and

growth profile)

- Damage limits.for control components

This model applies ONLY to the MCB itself

- Not intended for other electrical cabinets/panels

- Not intended for MCR "back-panels"

- Not intended for the relay rack room or other similar areas

Fife PRA Wo,*shop, 20S,fWoshtngt, DC s 4 A Co~ehoxehIe of &.S NROS. oNC o /sI eReguAtRey

Modl.e fi PM. 2: SpeIal Fir Modl.s Part2 Pd 2- h (RES) & E-eti Power R- •h -stitte (-PR)

2-194
Slide 5 Notes:

! Module I1-11, Pt. 2: Special Models Part 2 Main Control Board Damage Likelihood Model

* To use the model you must first identify your target set

- Example: two control switches on the MCB

* Determine the minimum separation distance between the

most remote members of the damage set

- Consider cable routing within the panel!

* Using this distance, go to the probability curve and'estimate

the conditional probability that given a fire somewhere in the

MCB, the specific zone encompassing the target set will be

damaged

* The resulting number includes BOTH the severity factor

AND the probability of non-suppression

- It does not include fire frequency!

Re PRA i 2W M Fi Wehle n Put52 DC C bRES e C fik P e R CMtOEV

ModueM INPt 2: Special ffm Mods Punt L___ RN Se RES) & Finih Pen, fno t dn (50

2-195
Slide 6

I Module I11-11, Pt. 2: Special Models Part 2

Main Control Board Damage Likelihood Model

* Example:

- Target set is two switches

located 0.5 m apart from each

other

- Inspection shows that the cables

leading to each switch are routed

in opposite directions such that 2

ft is the minimum separation

distance between the switches

- The MCB contains only IEEE383 certified low-flame-spread

cables

- The conditional probability that a

fire occurring somewhere in the

MCB will damage the target set

is approximately 3.OE-3

Probability of Target Damage: [SFP5,](d)

0.0 0.5 1.0 1.5 2.0 2.5

1.O0E-01

3.0

Damage Distance [mn]

Fire PRA Wor*shop, 2008, Washington DC

Module Ill Pt 2: Special Fire Models Part 2

Slide 6 i A Collaboration of U.S. NRC Office of Nuclear Regulatory

Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-196
Slide 7 Notes:

! Module I1-11, Pt. 2: Special Models Part 2 Turbine Generator Set Fires

Four types of fires can occur involving the turbine generator

set, and each is treated differently:

- Electrical fires in the exciter

- Hydrogen fires:

- General oil fires

- Catastrophic failure (e.g., blade ejection)

Fn PRA W 2,'•00 *. 2008 DC008t100 A Co°oabn 22U00R Ofika°f 0020.10,

MOdU. IN Pf 2: SpýeialFIMode1. Port 0. 9sF-7 (RES) d 8.0 o w0erRFrnw (EPR0

Slide 8 Notes:

! Module Il1-11, Pt. 2: Special Models Part 2 Turbine Generator Set Fires: Exciter Fires

" Exciter fires do occur, but all evidence indicates fires remain

small and non-threatening

- No evidence of any exciter fire that led to damage to anything other

than the exciter itself

- No attempt was made to estimate likelihood of a severe exciter fire

(one that challenges external targets)

* Recommended Practice:

- Assume exciter fires remain confined to the exciter

- Verify for your application, but should not represent a significant risk

contributor

Fre PRA Workho,0, 2008. 0 Wa0h1g1o DC 2 0A 2o &U.S. NRC On0oa o N f R00 td10 1o

Modul IN Pt 2: Specl.l Pr0 Modes P.t 2 R08mh (RES) A 0011oe R0ý ,fMlh In t 06pR0

2-197
Slide 9 Notes:

Module I11-11, Pt. 2: Special Models Part 2

Turbine Generator Set Fires: Hydrogen Fires

Database shows 13 TG set hydrogen fires, two categorized

as severe, the rest were small leaks (generally associated

with seals) with limited damage range

For small fires:

- Assume damage will be limited to within a few feet of the point of

release

- Secondary ignitions should be considered and treated if there are

nearby combustibles

- See more in Hydrogen Fires discussion (Appendix N)

Few PRA Wo0•t , 220a S"Sh"Z DC s A C2 Ou o 8S. NR0 0l31°0 u a-eo 090 u r0

Module MOP 2: Special Rm Modell Pafst R e n- (RES8)&e8d824 Poweý Res h MItlu (EPRO

Slide 10 Notes:

! Module 111-11, Pt. 2: Special Models Part 2 Turbine Generator Set Fires: Hydrogen Fires

For severe fires, widespread damage may occur due to an

explosion or detonation of the hydrogen gas.

- Assume fire may damage all Fire PRA cables and equipment within

the line of site of the generator and its bearings (including above and

below)

- Hydrogen explosion could cause some structural damage as well

- For further discussion - see Hydrogen Fires

F" PRA Wo,*o• , 2008, Washington DC i A do S NRC oe o r OO sO,

Module III Pt 2: Speoial Fre Models Pe.r2 24 h (RES) & EleOtric P rRo h 05t018 (FF00

2-198
Module I11-11, Pt. 2

Turbine Generator Se

International experien

catastrophic turbine fa

damage including strun - Examples: Vandellos

(1991)

- Events involve a comb

release, and large oil fi

Domestically, only oni

these elements (Salen

- Event involved minor d

suppression system an

- Indicates that both aut

brigade should be cred

observed internationall

FA. PRA Wo,2Mwo, .,0.9 w, OC

MHoduk IN Pt 2. Sped.I F* odd pa P.t 2

Slide 11 Notes:

Special Models Part 2

It Fires: Catastrophic Failure

ce includes a few fires initiated by

tilure that resulted in widespread

Ictural damage

(1989), Narora (1993), Chernobyl Unit 2

ination of turbine blade ejection, hydrogen

res.

e event came close to involving all of

m, 1991)

lamage due to existence of an automatic

nd prompt fire brigade response

omatic fire suppression systems and fire

dited to prevent catastrophic consequences

y S A C f•ojtoaN0,•S. NRC NfIt. oS NuoC..,Regutafo

R.seeoh IC-S) S ESel&dEftd R -a, Of , fEPRQ

Slide 12 Notes:

! Module I11-11, Pt. 2: Special Models Part 2 Turbine Generator Set Fires: Catastrophic Failure

Screening approach: assume that the conditional probability

that given a T/G set fire, the event will involve catastrophic

failure (e.g., blade ejection), hydrogen, and oil fires:

1 over 38 events or 0.025

- With successful suppression, damage would be limited to the T/G

system, as was the case at Salem

- In case of failure of all suppression, automatic and manual, assume

loss of all Fire PRA cables and equipment in the Turbine Building

Possible failure of exposed structural steel as well

- Estimate screening CDF contribution, refine as appropriate

FiR PRA Worshop, 2008, Washlngton OC [ -o AColob•t•noh OW $ NRC Office So , 00"Nr y

Module Ill Pt 2: Special RP Models P-r 2 -es..h IRES) &E-Ctc PR R -obh 50100 (EPRIR

2-199
Slide 13 Notes:

! Module Hydrogen i1.1-1, Fires Pt. 2: Special Models Part 2

This discussion (Appendix N) applies to general hydrogen

fires

- Including TG set fires

- Also other source of hydrogen leaks and releases (e.g., recombiners,

storage tanks, piping, etc.)

* The intent was to provide general discussion of hydrogen

fires and their potential effects

* The discussion stops short of recommending modeling

approaches, but does provide references to various

information resources

F "u PRA W o rkeh op, 20M . WM• h0 gto0 DC F e 13b] A -lSbO re on fus NRC O O ftfce o N g

Module i f 2: Special R•n 1Mod. Pert Re rh (PRE) &SeIPO pc .e (ReMh t.tt (EpRp)

Slide 14 Notes:

! Module I1-11, Pt. 2: Special Models Part 2 Hydrogen Fires

Two general types of fires:

- Jet fires originating at point of a H2 leak

- Critical question will be flame length

- Explosions

* If there is a mechanism for the release of large quantities of H2 (e.g., a

large leak, a prolonged leak that might not be ignited early) then

likelihood of a hydrogen explosion is high

* References provide additional resources for assessing damage potential

for an explosion scenario

C Critical question will be the severity of the overpressure

Fir PRA WW*ehop, 200PWeehpMgfon OF S A Coloron cZ UE NRC Office oNudeer-RWeoty

Modue W Pt 2.: Spedial ri Models PeH 2 -e-eeh (PER) .E eP- P-eesPeeh Ipode (R.1E )

2-200
Session lOb: Example Problems

2-201
Workshop Problems on Task 11a: Detailed Fire Modeling

This handout includes workshop problems on the different steps of Task 11: Detailed Fire

Modeling. Problems are grouped according to the steps defined in NUREG/CR-6850. Detailed

fire modeling will be conducted in the switchgear access room (Room 9) located in elevation 20

ft of the auxiliary building.

Workshop Problem Set 11a-01

Step 1a: Identify and Characterize Compartments: Review the following information

necessary for fire modeling purposes.

- Room size: For the purpose of this exercise, assume the size of the room is 45' by 22'

by 20' high.

- Wall boundaries: The surfaces, floor, ceiling, and walls are reinforced concrete. All the

surfaces are 2' thick.

- Doors: The room has three doorways: 1) a double door connecting to switchgear room

A, 2) a double door connecting to switchgear room B, and 3) a single door connecting to

the stairwell. The size of a single door is 6.5' by 3'.

- Mechanical Ventilation: The switchgear access room has a mechanical ventilation

system with a balance 5 air changes per hour.

2-202
Workshop Problem Set 11a-02

Step 2a: Identify and Characterize fire Detection and Suppression Features and

Systems: Review the following information necessary for fire modeling purposes.

- Prompt detection: Prompt detection is not credited since there is no incipient fire

detection system in the room and no continuous fire watch.

- Prompt suppression: Prompt suppression is not credited since there is no continuous

fire watch in the room.

- Fixed fire detection system/s (type, and sensor location): An automatic fire detection

system is credited since the room is equipped with an automatic fire detection system.

The location of the relevant detectors is specified in the corresponding scenario

descriptions later in this document.

- Fixed fire suppression system/s (type and nozzle location): An automatic 002 system is

credited since the room is equipped with an automatic 002 system. Upon smoke

detection alarm, a timer starts providing 60 seconds delay for life safety purposes. The

C02 is released after the delay time. The soak time is approximately 20 min.

Fire brigade arrival time: The fire brigade arrival time is assumed to be 15 min.

Delayed detection: Delayed detection is credited and assumed to be 15 minutes

(consistent with the example in page P-14 of NUREG/CR-6850).

2-203
Workshop Problem Set 11a-03

Step 3a: Characterize Fire Ignition Sources: From the Task 6 (Fire Ignition Frequencies)

calculation package, list the fixed ignition sources located in the switchgear access room (room

9) and assign a heat release rate probability distribution to each of them from Table C-1 of

NUREG/CR-6850.

Solution: Table 1 lists the recommended answer to workshop problem 3.

Table 1: Summary of ignition source characteristics in the switchgear access room.

Equipment Description CID ase (Table E-1 of HRR Profile

Equipment NUREG/CR-6850) (Page G-6 in NUREG/CR-6850)

MCC-Al

MCC:B13

VITAL-A

VITAL-B

Transients

2-204
Step 4a: Identify Secondary Combustibles: No workshop problem is associated with this

step. The following discussion provides an example of how to identify and characterize

secondary combustibles.

Sample Analysis for Step 4a:

For the purpose of this example, let's assume that there is one cable tray stack above each

cabinet in the room. Each stack has two trays. The first tray is 1' above each cabinet. The

second tray in the stack is 1.5' above the first tray. The trays are ladder-back. A pictorial

representation of the secondary combustibles in provided in Figure 1.

Secondary

combustibles

Front view

Figure 1: Pictorial representation of the secondary combustibles. Drawing not to scale.

From Table 1, the cabinets in the switchgear access room will have a peak heat release rate of

211 kW. Heskestad's flame height correlation (Chapter 3 of NUREG 1805) suggests a flame

height of approximately 4.6' above the ignition source. Therefore, the cable tray stack above

the cabinet is expected to ignite and contributing to the fire intensity. Table 2 lists the

Heskestad's flame height correlation analysis.

Table 2: Heskestad's flame height correlation analysis.

Heskdestad's Flame Heiaht Correlation I

Inputs

Fire diameter [m] 0.6

HRR [kW] 211

Results

Flame height [m] 1.4

Flame height [ft] 4.6

2-205
Step 5a: Identify and Characterize Target Sets: No workshop problem is associated with this

step. The following discussion provides an example of how to identify and characterize target

sets. In practice, this step requires highlighting of cable tray and conduit targets in room layout

drawings based on cable routing analysis and plant walkdowns.

Sample Analysis for Step 5a:

For the purpose of this exercise, let's assume that there are two target sets in the room:

1) HCBT-35A and HCBT-35B, and 2) VCBT-20A, and VCBT-20B. These trays are identified in

Figure 2. The trays have both thermo-set and thermo-plastic cables. Specifically, a fire

damaging either the two horizontal trays or the two vertical trays will generate the postulated

plant condition.

Figure 2: Cable tray locations in the switchgear access room

Tray locations:

* HCBT 35A: This horizontal tray comes into the switchgear access room from switchgear

room A. The tray is the second tray in an elevated stack. The lowest tray in the stack is at

elevation 33' (13' from the floor). The target tray, HCBT 35A, is at elevation 35' (15' ft from

the floor and 2' above the lowest tray in the stack).

*HCBT 37B: This horizontal tray comes in the south direction into the switchgear access

room from switchgear room B and turns west. The tray is the first tray in an elevated stack.

It is located at elevation 37' (17' from the floor). At the point the cable tray crosses HCBT

35A, it is the third tray in the stack.

* VCBT 20A: This is a vertical cable tray in the south west corner of the room. The tray

comes into the room through a floor penetration at elevation 20' and runs up to the ceiling.

* VCBT 20B: This is a vertical cable tray in the south west corner of the room. The tray

comes into the room through a floor penetration at elevation 20' and runs up to the ceiling.

Workshop Problem 11a.04

Step 6a: Define the Fire Scenarios to be Analyzed: Define the fire scenarios to be analyzed

in the switchgear access room using the information provided or collected in the first five steps.

• Fixed ignition source fire scenarios:

Solution:

2-206
* Transient ignition source fire scenarios:

Solution:

2-207
Step 7a: Conduct Fire Growth and Propagation Analysis: For the purpose of this workshop,

only two of the fire scenarios listed in the previous section are analyzed in detail: Scenario 1,

and Scenario 4.

Workshop Problem I a-05:

Determine if a fire in the ignition sources associate with scenarios 1 and 4 can produce room

wide damage in the switchgear access room. If the ignition sources alone are not expected to

generate room wide damage, determine the amount of secondary combustibles necessary to

achieve it.

Solution:

2-208
Workshop Problem 1 la-06

Determine the time to target damage, time to smoke detection, time to automatic suppression

and the fire brigade arrival time for scenario 1.

Solution:

2-209
Workshop Problem 11 a-07

Determine the time to target damage, time to smoke detection, time to automatic suppression

and the fire brigade arrival time for scenario 4.

Solution:

2-210
Workshop Problem 1la-08

Let's assume that MCC-A1, which is the ignition source in scenario 1 it's a 4160V switchgear.

In this case, a high energy arcing fault event should be also postulated and evaluated.

Determine if the cable tray targets will be within the zone of influence of a high energy arcing

fault.

Solution:

2-211
Step 8a: Conduct Fire Detection and Suppression Analysis: The detection and suppression is

reflected in the risk analysis with the non-suppression probability, which is calculated using a

Detection/Suppression event tree approach discussed in Appendix P of NUREG/CR-6850,

Detection and Suppression Analysis. Recall that the switchgear access room is equipped with a

smoke detection system, and an automatic CO 2 system. The CO 2 system has a 60 second

warning alarm delay. In addition to these fixed systems, the fire brigade can also provide manual

.suppression activities.

Considering the above fire protection features, the suppression strategy in the switchgear

access room can be summarized as:

1. Indication of smoke detection in control room

2. Control room sends an operator to the switchgear access room to confirm the fire

3. If fire is confirmed, the operator first if the automatic CO2 system operated.

4. If further suppression activities are warranted after any of the automatic systems, manual

suppression by the fire brigade may be used.

Workshop Problem Set 11a-09

Develop a detection suppression event tree for the fire protection strategy defined above.

Solution:

2-212
Workshop Problem Ila-10

Step 9a: Calculate Conditional Non-Suppression Probability and Severity Factor:

Determine the severity factor and the non-suppression probability for scenario 1.

Solution:

2-213
Workshop Problem 11a-ll

Step lOa: Calculate Scenario Frequency: Using the ignition frequency calculated in Task 6

for the ignition sources in the switchgear access room, and the severity factor and nonsuppression probability calculated in the previous step for scenario 1, determine the frequency

for fire scenario 1.

Solution:

2-214
Session 11a: Main Control Room Fire Analysis

2-215
Slide 1 Notes:

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Task lb - Main Control Room Fire

Analysis

Joint RES/EPRI Fire PRA Workshop

September 2008

Washington DC

A Colabortion ofU.S. NRC Ofice of Nucle.r R~eguletof..R.osarh (RES) & Electric Power Researh Institute (EPRO

Slide 2 Notes:

Main Objectives Control Room Fire Analysis

The objective of this module is:

- Describe~the recommended approach for detailed fire

modeling in the main control room. Specifically:

- Differences between the main control room and other

compartments

- Criteria for abandonment due to fire generated environmental

conditions

- Description of how to calculate:

* Forced control room abandonment time

* Conditional probability of damage to a target set

Fire PRA Wnrk.h, 200 8, ftshvlgton DC Sj;; A2 a CdOboJn0 f U NRC OS oo!NWn--l9r-tnY

Trok 175 . , nlei on R , . AI•-JtRnH s Re00.08 (RES) & E-- Pns, R.•S h 1-t1u. (E-RI)

2-216
Slide 3 Notes:

! What Main Control Room Fire Analysis is Different in the MCR?

The control and instrumentation circuits of all redundant

trains for almost all plant systems are present in the control

room.

- Redundant train controls may be installed within a short distance

- Small fires within control panels may be risk-significant.

* The room is continuously occupied, which provides the

capability of "prompt detection and suppression."

* Evaluating control room abandonment conditions is

necessary.

- Abandonment refers to situations in which control room operators are

forced to leave due to untenable fire generated conditions

(temperature, toxicity, and visibility).

F p.A P R. h, 2MOS,w o,, n s. a * C otomNn 0U. NRC Ot otN,. WReoatory

Tflib f l b .-Man, Co(troi Ro RMAmyuI R (RES) & EB'Ri P ow R 0.4t W (EPRR

Slide 4 Notes:

Main Control Room Fire Analysis

Recommended Steps

* Step 1: Identify and characterize main control room features

* Step 2: Estimate control room fire frequency

* Step 3: Identify and characterize fire detection and suppression features

and systems

* Step 4: Characterize alternate shutdown features

* Step 5: Identify and characterize target sets

* Step 6: Identify and characterize ignition sources

* Step 7: Define fire scenarios

* Step 8: Conduct fire growth and propagation analysis

* Step 9: Fire detection and suppression analysis and severity factor

* Step 10: Estimate failure probability of using alternate shutdown

features

* Step 11: Estimate probability of control room abandonment

* Step'12: Calculate scenario frequencies

* Step 13: Document analysis results

Fie PRA Wors/Cm. 2W8R. WaOOCOgt DC SI/ Mf aR- UOS)UA NRC C•,• NIC•h d*R*Pt°

TIMk f1b . M1iR CoR1oI Rom FieM ARfyUls RORR ICES) S Ectri Po ROOOh ROCCO* (ERR)

2-217
Slide 5 Notes:

Main Control Room Fire Analysis

Step 1: Identify and Characterize MCR Features

The specific features of the control room and the control board are

identified.

* Control room dimensions

* Other adjacent compartments included in the MCR proper

* Location, shape, dimensions and special features of the control panels

and other electrical panels

Main control board layout and location of various controls and displays

Cable penetration into the control room and into the control panels

Ventilation system characteristics

Wall construction type and thickness:

False ceiling features and the ceiling above it

False floor and cable channels under the floor

Openings in the false ceiling should be~specifically noted as potential

pathway for hot gases entering the area between the two ceilings.

* Problem Set I Ib-01 (Example)

F PpR A W ok h . 20 0 . WA o D C . .RC ol N d R IW y

Taý f .Man co.nl Room RnRMAnaWid 3lCPmor RýC S R SLRW EPOt)

2-218
Slide 6

Main Control Room Fire Analysis

Step 2: Control Room Fire Frequency

The MCR fire frequency includes contributions from the Main Control Board (bin #4), PWC -

Electrical cabinets (bin #15), PWC- Self Ignited Cable Fires (bin #12), Control/Aux/Reactor

Bldg. - general transient fires (bin #7), transient fires caused by welding and cutting (bin

#6) and cable fires caused by welding and cutting (bins #5) as follows:

XMCR = WLMCR(QMCB + WPWC,Elec.CabMCR XPWC,Elec.Cab.

" W PWC,SICF )PWC,SICF + WCAR,trans,MCRxtransient

+ WCARweld, MCRXCARwelding+ WCAR,weld cablesMCR XCAR, weld-cables)

Problem Set 11.b-02

Fire PRA Workshop, 2008, Washington DC S A Collaboration of U.S. NRC Office of Nuclear Regulatory

Task I lb - Main Control Room Fire Analysis L ............................... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-219
Slide 7 Notes:

Main Step Control Room Fire Analysis 3: Fire Detection and Suppression Features

The detection and suppression features that may be credited

when analyzing the fire scenarios are identified in this step.

* Smoke detectors (false and main ceilings and control

panels)

* Detectors in the ventilation ducts and their function

* Fixed fire suppression systems inside and outside the

control panels,

* Location and characteristics of portable fire extinguishers

* Location and characteristics of hose reels.

* Problem Set I lb-03 (Example)

F"b PRA W p. 2M.8 Wa84no f05105 DC * A o - b US NRC taqi.A - R-- d..Y

Task 55 ffsMain 0. R- Roo RmAslysl-s . 0 I

Slide 8 Notes:

Main Control Room Fire Analysis Step 4: Characterize Alternate Shutdown Features

The features of alternate shutdown capability vary widely among

NPP's

* In general, a control panel is installed at a location away from the

control room where the operators can control and monitor key core cooling functions and parameters independent of the MCR.

* In other plants, alternate shutdown capability is achieved through a set of control points and control panels located at various

points of the plant requiring coordinated actions of several

operators.

* It is necessary for the fire risk analysts to understand the

alternate shutdown capability of the plant. - For example, the analyst may select safety-related target sets on the

panel that are not backed up by an alternate shutdown control or instrumentation circuit.

* Problem Set I b-04 (Example)

R.s PR. wOrUshp0, 2"08. W008,n~loU DC S A C°osiaUU NRC 0t'05 ana NL 0,181t,

Task f11b-Main Cw" Room ft = Anaiysis 0855h IRUSI Wr) & 0 lows .. h 051888 (EURO

2-220
Main Control Root Step 5: Identify and C

The target sets can be id

combinations of control a control panels, electrical

inside the MCR.

* Examine the control pa

* Groups of adjacent con

* Cursory and conservat

the basis

* Elements of a set are Ic

* Exposure fire affecting

* Problem Set 1 1:b-05

Fnro PRA WRtksop, 2008. hgWoftg DC

Ta I 1b . Main C-A0.1 Room Ff. An•.".

Slide 9. Notes:

m Fire Analysis

haracterize Target Sets

entified by systematically examining nd instrumentation items found on the

cabinets, wireways, and cable raceways

nels from one end to the other

trols and instrumentation

ive estimation of the CCDP/CLERP as

ocated within the reach of a potential fire

multiple cabinets

sua g A CG-tOi.o )US NRC D~m WNt RKiSIOY

Slide A (RED) • RAR (BARD Notietts: 

Slide 10 Notes:

Main Step 6: Control Room Fire Analysis Identify and Characterize Ignition Sources

The final product of this step is a list of ignition sources, their

relevant characteristics, and fire ignition frequencies

associated with each source

* Similar to Step 3.a of single compartment analysis

* Type, quantity, dimensions and heat release rate profile of each

source

* Main control board as ignition source

* Assume fire might occur at any point on a control panel

* Other control panels, electrical cabinets, wireways, and cable

raceways

* Kitchen appliances and other electrical devices?

* Transient combustible fires

* Frequency of fire ignition based on Step 2b analysis

* Problem Set 11.b-06

Fre PRA WoSshop, 2W08, VIMrR gfoQ DC A EdAbo.o, ADD. NRC O a iNda Rabv T.As IlbA -Main Coro R-R Fi Anaiysý R-Rch (RES) A EAerc Po sn Rs ti•e (EARm)

2-221
Slide 11 Notes:

Main Control Room Fire Analysis Step 7: Define Fire Scenarios

Four types of fire scenarios are specifically recommended for

evaluation

* Fire inside the main control board and stand-alone

electrical cabinets that are open into each other,

* Fires affecting two adjacent electrical cabinets that do not

open into each other; and

* Fires affecting two non-adjacent electrical cabinets,

* Transient fires

R. PRA WvlkvRC 2M0& Iaa'gV'° CC DCNCM.,R.9~y • A * °& U& NRC 

Tfsk lf -Mallh* Roo R FreAnl. i,•a R (R, S) & E-cMCPn RwR- -nA e (EPR#

2-222
Slide 12

I Main Control Room Fire Analysis

Step 8: Fire Growth and Propagation Analysis

The methodology suggests the following specific approach

for conducting fire growth and propagation analysis:

• Fire inside the main control board

- Use Appendix L

Probability of Target Damage: [SF.P.Jd)

00 Os 0 10 15 20 215 30 1 000.-01

-- 0- Qualified

1.0OE-02 -4- Unqualftd

1.00E-03

1.00E-04

1 00E-05

Dane Distuce mI

Fire PRA Workshop, 2008, Washington DC

Task 11b - Main Control Room Fire Analysis

SSlide 12 I A Collaboration of U S. NRC Office of Nuclear Regulatory _........... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-223
Slide 13

Main Control Room Fire Analysis

Step 8: Fire Growth . (cont'd)

A probabilistic model of the main control board fire spread

estimates the likelihood that a set of targets separated by a

predetermined distance would be affected by a fire.

" Difficult to model fire spread within a cabinet using current

state-of-the-art analytical tools.

" Probabilistic model based on EPRI's Fire Events Database

and cabinet fire experiments reported in NUREG/CR-4527.

* The likelihood is a combination of severity factors and nonsuppression probabilities

A(d) -- AMCB [SF. Pns ](d)

Fire PRA Workshop, 2008, Washington DC Slide 13 A Collaboration of U.S. NRC Office of Nuclear Regulatory

Task I lb - Main Control Room Fire Analysis ............................... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-224
Slide 14

Main Control Room Fire Analysis

Step 8: Fire Growth... (cont'd)

The likelihood is a combination of severity factors and non-suppression

probabilities integrated over all possible fire events inside the panel that

may damage the postulated target set.

* All possible fire origin locations

,A(d) =,MCB [SF. Pns ](d)

0-"- 0

d

° W

I H

h

I

IHW

[SF .Pns(d) - f JSF(dw,h).Pns(dw,h)dwdh H' 00

Fire PRA Workshop, 2008, Washington DC A Collaboration of U. S. NRC Office of Nuclear Regulatory

Task Ilb - Main Control Room Fire Analysis . .................... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-225
Slide 15

Main Control Room Fire Analysis

Step 8: Fire Growth... (cont'd)

" Two adjacent but separated control cabinets

- No propagation if panels are separated by a double wall with an air

gap (Appendix S)

- If separated by a single wall,

- If open back panels, check for direct radiation or other damaging fire

generated conditions

" Non-Adjacent cabinets

2 Adjacent Cabinets (da) = 2 MCB [SF. Pns ](da ) Pns (15 min)

- Very small likelihood of damage among non-adjacent cabinets

- Check for transient fires between cabinets

- Assume time to target damage of 15 min if there is direct exposure

from the fire to the panel walls

- Problem Set 11.b-07

Fire PRA Workshop, 2008, Washington DC ...... S 1A . Collaboration of U.S. NRC Office of Nuclear Regulatory

Task i F b - Main Control Room Fire Analysis D . Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-226
Main Control Roo,

Step 9: Non-Supp Pro

The non-suppression

calculated as recomm compartment fires

- For fires inside a con

in Appendix L

FwO PRA i*,*.hop, 200D, W gtn DC

TPsk f1b. Main ContoI Room FPh Anatysi

Slide 16 Notes:

m Fire Analysis

b & Severity Factor

probability and severity factors are ended in the approach for single

ntrol panel, use the method described

Sid. 16 A C -6•060 60 u1 Nn1 M. -0 Rab .1

Slide 17 Notes:

! Main Control Room Fire Analysis Step 10W Estimate Failure Prob Using ASP

Two approaches may be followed:

- An overall failure probability is estimated representing the

failure of the alternate shutdown means.

- The alternate shutdown procedure is integrated in the plant

response model (i.e., the fault trees and event trees). The

core damage sequences are adjusted to include failures

associated with alternate shutdown means, and the human

error probabilities are reevaluated based on the alternate

shutdown procedures.

Fin PRA Woik~lop, 20'8, IbhWIngon DC l A Co nl S NR1 OffieodaN Rguaty

Tank 11b - Main Cnntl Ram l, AnaHysis R6. h RESl P r (EPPM1

2-227
Slide 18 Notes:

Main Control Room Fire Analysis

Step 11: Estimate Prob of Control Room Abandonment

The final decision to abandon the control room is assumed

to depend on habitability conditions.

* The analyst may postulate that the alternate shutdown

procedure would be activated

* The time to activate the alternate shutdown procedure is

suggested to be established based on plant operating

procedures rather than control room habitability conditions

* Abandonment possibility should be examined for all

postulated target damage scenarios

Fk PRA orkshop, 2W08. WA0h8gAf DC 8 A Cb UC NRC 008. D~C R•R0at0

fl Iftb -Main ConOW Room Fir Anaysis Rfch (RES) &E E PRoer Rn..lrc 0n8. (EPRO

2-228
Slide 19

Main Control Room Fire Analysis

Step 11: Estimate Prob of Control Room Abandonment

Abandonment criteria based on habitability conditions

" Temperature, or heat flux

- The heat flux at 6' above the floor exceeds 1 kW/m2. This can be

considered as the minimum heat flux for pain to skin. A smoke layer

of approximately 95 0C (2000F) could generate such heat flux,

4"= uT4 c z 1.0 kW/m 2

* The smoke or hot gas layer descends below 6' from the floor

" Visibility

- Optical density of the smoke is less than 3.0 m-1. With such optical

density, a light-reflecting object would not be seen if its more than

0.4m away. A light-emitting object will not be seen if it is more than

1 m away.

* A panel fire affects two target items 2.13 m (7') apart.

Nire PRA Workshop, 2008, Washington DC l 1. A Collaboration of U. S. NRC Office of Nuclear Regulatory

Task l Ib - Main Control Room Fire Analysis .Slide 1 Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-229
Slide 20 Notes:

Step Main 11: Control Estimate Room Prob Fire of Control Analysis Room Abandonment

The conditional probability of abandonment can be estimated

based on the calculated evacuation time.

* Determine the heat release rate generating abandonment

conditions

* Calculate the severity factor for fires of this size

* Determine the time for abandonment

- Time to reach untenable conditions such as 200IF hot gas layer or

smoke density conditions of 3.0 m-1

* Calculate non-suppression probability

* Multiply the severity factor and non-suppression probability

to determine conditional abandonment probability.

Fka PRA Woks•*, 2008, "M.-on DC . 2 C[jo;;;t72f WS. NRC Ofir.Oft- Rfl,•WRU y

Tal 11b -Main CoMDWolRoomnFtnAna-FY.A Rftwnh (RES) & Ebddcd Pc , R-h Ituf. (EPRI)

2-230
Slide 21

Main Control Room Fire Analysis

Example

Credit prompt. detection

" Suppression by fire brigade

- Pns from CR suppression

cu rve

* SF from probability

distribution for vertical

cabinets with unqualified

cable and fire propagating to

more than one bundle.

" Problem Set 11.b-08 (Example)

Inputs

Ambient temperature [C]

Duration [sec]

Opening area [m2]

Height of opening [m]

Room length [m]

Room width [m]

Room height [m]

Thermal conductivity [kW/mK]

Density [kg/m3]

Specific heat [kJ/kg]

Wall thickness [m]

Temperature for abandonment [C]

20

4

2

20

15

6

0.0014

2000

0.88

0.15

93

Fire PRA Workshop, 2008, Washington DC

Task 11b - Main Control Room Fire Analysis LId I" A Collaboration of U.S. NRC Office of Nuclear Regulatory Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-231
Slide 22

I Main Example Control Room Fire Analysis (cont'd)

2.5E-01 

900

2.5E-01

1.5E-01 9Af i70

900

800

700

600

500'

400

300

200

100

0

5.OE-02

0.OE+00 Acl

0 10 20 30 40 50 60 70

Time for a 200 F HGL

-s-SF & Pns --- HRR [kW]

Duration [Min]

5

10

15

20

25

Required HRR [kW]

794

668

603

561

531

SF

3.2E-02

4.8E-02

6.OE-02

6.9E-02

7.7E-02

Pns

1.9E-01

3.7E-02

7.1 E-03

1.4E-03

2.6E-04

SF*Pns

6.1 E-03

1.8E-03

4.2E-04

9.4E-05

2.OE-05

Fire PRA Workshop, 2008, Washington DC

Task Il b - Main Control Room Fire Analysis

Slide 22 A Collaboration of U.S. NRC Office of Nuclear Regulatory

........................................ I Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-232
Slide 23 Notes:

! Main Control Room Fire Analysis Concluding Remarks

The main control room has unique characteristics that are addressed in detail in Task 1 lb.

* Recommended fire scenarios for the MCR

* Evaluation of MCR abandonment due to fire generated

conditions

Fir PRA o,* I 2008. WtAýgloo ý DC S 3 Rt. (R CS) (ECP °, COR, RO TaJle fb. -Main Ca t Ren, • A eti•'Js -• rhRE &lerip R rhIfo PR

2-233
Session 11b: Example Problems

2-234
Workshop Problems for Task 11 b: Detailed Fire Modeling in the Main

Control Room

Workshop Problem Set 1 1b-01 (Example)

Step 1.b: Identify and Characterize Main Control Room Features: The following list

summarizes the key features of the Main Control Room (MCR):

* The MCR is located at Elevation 55ft of the Auxiliary Building. See Drawings A-01 and A07 for details.

* In this analysis, the kitchen and shift supervisor's office are included as part of Main Control

Room proper.

* The dimensions of the MCR proper are as follows:

- 15'ft high

- 50 ft long

- 30 ft wide

" Access to the kitchen and shift supervisor's office are solely from the control room

* The kitchen includes an electric water heater and a microwave oven, a refrigerator, a sink,

kitchen cabinets and a small dining table and chairs.

* The shift supervisor's office includes a desk, a computer and printer, chairs and large

quantity of reports, engineering documents and other paper documents.

* The Main Control Room includes the following:

- A horse shoe shaped main control board (MCB) (see Drawing A-09 for details)

- One free standing electrical panel where fire protection system display and controls are

mounted

- Two desks, assortment of chairs, book cases containing paper documents

- Two printers with continuous feed paper roll.

* The main control board (MCB) is 22 feet long and 9 feet tall

* The fire protection panel has only one segment (there are no divisional walls within the

panel). The panel is 8 feet tall, 3feet deep and 6 feet wide.

* The walls of the MCR are made of reinforced concrete with no penetrations in the ceiling and

the walls except for a ventilation opening in the east wall. There are sealed control cable

penetrations under the MCB and fire protection panel.

* Ventilation (heating, cooling and fresh air supply) is provided by a dedicated unit that

provides fresh air from outside and can be shut closed by the MCR operators and put on a

recirculation mode.

* There is a false ceiling 3 feet below the control ceiling of the MCR. The false ceiling is

composed of light non-combustible boards held by an aluminum structure.

2-235
The following list summarizes the key features of the Main Control Board (MCB):

* The Main Control Board is composed of 7 segments (CB-1 through Cb-7). See Drawings A01 and A-07 for details.

* Each Main Control Board segment is separated from the adjacent segments by a partial wall

that extends halfway inside the panel.

* All cables enter the panel from below through sealed penetrations.

* The insulation of the cable and wires is a mixture of thermoset and thermoplastic insulation.

* The back and top of the control panel is closed. There are doors on the side walls that are

normally closed.

• Instrumentation technicians enter the Main Control Board for various tasks no more than

once per week.

* There are no power cables in the Main Control Board.

2-236
Workshop Problem Set 1 lb-02

Step 2.b: Estimate Control Room Fire Frequency: For the overall MCR fire frequency the

equation provided on pages 11-33 and 11-34 of NUJREG/CR-6850 has been updated to read as

follows:

kMCR = WL,MCR(,MCB + WPWC,EIec.Cab,MCR.XPWC,EIec.Cab. + Wtransients,MCRktransient +

Wwelding,MCRwelding + WCable,MCRkcable)

where:

XMCR . Main Control Room fire frequency

WL, MCR Location weighting factor for the MCR

XMCB : Main Control Board fire frequency (Table 6-1, bin 4)

WPWC, Elec. Cab, MCR.: Ignition source weighting factor of Plant Wide Electrical Cabinets

found in the Main Control Room.

XPWC, Elec. Cab.

Wtransients, MCR:

Xtransient :

Wwelding, MCR

Fire frequency of Plant Wide Electrical Cabinets (applies to all electrical

cabinets in the plant including those panels in the MCR that were not

labeled as MCB.) (Table 6-1, bin 15)

Ignition source weighting factor of Control/Aux/Rx Bldg Transient Fire

events that may occur in the MCR. This fraction should be computed

using the same method as for transients for other parts of the location

using the following influencing factors:

- Maintenance - Low

- Occupancy - High

- Storage - High (reflecting large quantity of paper materials)

Control/Aux/Rx Bldg Transient fire frequency (Table 6-1, bin 7).

If welding is allowed in the MCR during power operation, this ignition

source weighting factor should be evaluated in the same way as that for

transient fire using the following influencing factors:

- Maintenance - Low

Control/Aux/Rx Bldg, transient fires caused by welding frequency

(Table 6-1, bin 6).

Ignition source weighting factor of Control/Aux/Rx Bldg Cable Fires

Caused by Welding and Cutting that may occur in the MCR. This fraction

should be computed using the same method as for transients for other parts

of the location using the following influencing factors:

- Maintenance - Low

Control/Aux/Rx Bldg, cable fires caused by welding frequency

(Table 6-1, bin 5).

Xwelding:

WCable,MCR:

kcable

2-237
Workshop Problem Set 11b-02 (continued)

Step 2.b: Estimate Control Room Fire Frequency: Using the information provided in this

Sample Package, and the above formula copied from NUREG/CR 6850, estimate the frequency

of fire for the SNPP MCR.

WL, MCR =

,MCB =

Wpwc, Elec. Cab, MCR. -

XPWC, Elec. Cab. -

Wtransients, MCR =

ktransient =

Wwelding, MCR =

,welding =

WCable,MCR: =

kcable =

per

per

per

per

per

per

per

per

per

per

kMCR =

2-238
Workshop Problem Set 11 b-03 (Example)

Step 3.B: Identify and Characterize Fire Detection and Suppression Features and Systems:

The following list summarizes the key features of the fire detection and suppression systems of

the Main Control Room (MCR):

" At least two qualified operators are present in the MCR at all times.

" There are smoke detectors under the false ceiling

* There are smoke detectors above the false ceiling

" There are portable fire extinguishers inside the kitchen and inside the Control Room area

* There is a wet hose reel in the Control Room Access area that can reach anywhere within the

control room

* The ventilation system can be switched to smoke purge mode to exhaust the air from the

control room to the outside.

2-239
Workshop Problem Set 1 lb-04 (Example)

Step 4.B: Characterize Alternate Shutdown Features: The following list summarizes the key

features of the Alternate Shutdown Panel:

* The Alternate Shutdown Panel is located at El. +20ft, in the SWG Access Room. The panel

is located at the North wall between the two switchgear room doors.

* The following list of components can be controlled from the Alternate Shutdown Panel.

Equipment ID

HPI-A

HPI-B

AFW-A

AFW-C

AOV-2 (SOV-2)

MOV-1

MOV-2

MOV-9

MOV-10

MOV-11

MOV-14

MOV-15

MOV-1 8

MOV-1 9

LI-1

LI-2

A-1

EDG-A

EDG-B

Equipment Description

High pressure safety injection pump A

High pressure safety injection pump B

Motor driven AFW pump A

Motor driven AFW pump C

Letdown isolation valve

HPI valve

VCT isolation valve

HPI valve

AFW discharge valve

AFW discharge valve

AFW turbine steam line isolation valve

AFW steam inlet throttle valve

AFW C Pump Discharge

AFW test line isolation valve

RWST level

RWST level

AFW motor high temp

Train A Emergency Diesel Generator

Train B Emergency Diesel Generator

Power Supply

4.16kV Bus A

4.16kV Bus B

4.16kV Bus A

4.16 kV Bus 2

125 VDC Bus B

480V MCC Al

480V MCC B1

480V MCC B1

480V MCC Al

125 VDC Bus B

125 VDC Bus B

125 VDC Bus B

480 V MCC-2

480 V MCC-2

120VAC Bus A

120VAC Bus B

120VAC Bus A

PNL-A

PNL-B

Control Room

Panel

CB-5

CB-5

CB-3

CB-3

CB-5

CB-5

CB-5

CB-5

CB-3

CB-3

CB-3

CB-3

CB-3

CB-3

CB-5

CB-5

CB-3

CB-6

CB-6

• To activate the alternate shutdown panel, the operators have to enter each switchgear room

separately and transfer the controls of the desired components from the Main Control Board

to the Alternate Shutdown Panel.

* A separate set of procedures exists for taking control at the Alternate Shutdown Panel.

2-240
Workshop Problem Set I1b-05

Step 5.b: Identify and characterize target sets: Identify at least five target sets for the Main

Control Room by inspecting drawings DWG A-07 and A-09 and other information provided in

this Sample Package.

Target Set Items in the target set Basis for selecting target set

ID

i i

2-241
Workshop Problem Set 11 b-06

Steps 6.b: Identify and Characterize Ignition Sources:

Steps 7.b: Define Fire Scenarios: For the target sets provided in the solution of the preceding

problem set, identify the corresponding ignition sources and fire scenarios.

Target Set ID Ignition Sources Fire Scenarios

MCR-01

MCR-02

MCR-03

MCR-04

MCR-05

2-242
Workshop Problem Set 11b-07

Step 8b: Conduct Fire Growth and Propagation Analysis

Step 9b: Detection and Suppression Analysis and Severity Factor: Using the information

provided in the solution to Problem Set 1 lb-03 and Figure L-1, conduct fire propagation,

detection and suppression analysis for the following fire scenarios and calculate scenario

frequency:

MCR-03.1

SFxPNS

kMCR-03.1 =

MCR-04.1

SFxPNS =

kMCR-04.1 -

2-243
Workshop Problem Set 11b-08 (Example)

Step 11.B: Estimate Probability of Control Room Abandonment: The following is an

example case presented here as an illustration on how the probability of abandonment can be

estimated

The probability of abandonment represents the likelihood of a fire generating adverse

environmental conditions meeting the criteria for control room evacuation described in Task 11

of NUREG/CR-6850. The abandonment criteria suggests that analysts must assume operators

will leave the control room if:

* The room or hot gas layer temperature reaches 200 TF (93 °C).

• The heat flux to the control room floor is above 1 kW/m 2,

* The hot gas layer is 6 ft or lower above the floor and has and optical density of 3.0 1/m.

Such optical density will prevent operators to see through smoke.

Considering these criteria, the abandonment probability was calculated as follows:

1. From Task 6, the ignition sources in the main control room are:

- the main control board,

- vertical electrical cabinets and

- transients.

2. The probability distribution for heat release rate Case 5 in Table E-1 of NUREG/CR-6850

has been assigned to the main control board and other electrical cabinets. This distribution

applies to cabinets with un-qualified cables and fire spreading to more than one cable bundle.

3. The time to abandonment was calculated deterministically for the range of heat release rate

values defined by the probability distributions listed in item 1 above. The zone model

MAGIC was used for these calculations. Relevant inputs to MAGIC include the geometry of

the main control room complex, and the mechanical ventilation system. The time to

abandonment is the shortest time when one of the three defined above criteria is met.

4. Each MAGIC result (i.e., the time to abandonment resulting from a specific heat release rate

input) is associated with a severity factor from the corresponding probability distribution for

heat release rate. Similarly, there is a corresponding non-suppression probability for each

MAGIC result. The non-suppression probability captures the likelihood that the fire will not

be suppressed before the calculated abandonment time.

5. The resulting abandonment probability and average abandonment times are a weighted

average of all the probabilities of fire sizes and corresponding non-suppression probabilities.

Table 3 summarizes the calculation of abandonment probabilities and average abandonment

times for electrical cabinets. The first column in Table 3 refers to the heat release rate value used

in MAGIC for determining the time to abandonment. The column labeled SF lists the severity

factor associated with the heat release rate value (taken from Appendix E of NUREG/CR-6850).

The Time column lists the resulting time to abandonment calculated with MAGIC. The column

labeled P,, lists the non-suppression probabilities. In general, Pns = exp(-Xt) where X for the

control room is 0.33 (see Appendix P of NUREG/CR-6850), and t is the time listed in the

"Time" column.

2-244
The average abandonment time is calculated as

Z o- t .SFj .P,,

a~b =

which is the weighted average of the abandonment times calculated with MAGIC. The

abandonment probability is calculated as

a'b SL.. P117

which can also be interpreted as an average non-suppression probability since the SFi's for all

possible heat release rates add to one. The following results are obtained using the two equations

above:

" Electrical cabinets: Average abandonment time is approximately 8 minutes and the

probability of abandonment is approximately 1.3E-2.

" Transient fires: For the purpose of this study, the time to abandonment and the

abandonment probability calculated for electrical cabinet fires is assumed to be the same as

for transient fires. This is a conservative assumption since the heat release rate profiles for

the electrical cabinet fire suggests higher fire intensities with faster profiles that are expected

to result in faster abandonment times.

Table 3: Time to abandonment and abandonment probability analysis for electrical cabinet fires.

Calculations assume no mechanical ventilation system in the room.

Time to Abb

HRR [kW] SF (min) Pns SF.Pns

1 0.0E+00 60 2.5E-09 0.OE+00

42 6.4E-01 60 2.5E-09 1.6E-09

197 1.6E-01 16 5.1E-03 7.9E-04

337 8.1E-02 11 3.1E-02 2.5E-03

475 4.7E-02 9 4.9E-02 2.3E-03

612 2.9E-02 8 6.4E-02 1.9E-03

749 1.8E-02 8 8.0E-02 1.4E-03

886 1.1E-02 7 9.4E-02 1.OE-03

1024 7.0E-03 7 1.1E-01 7.7E-04

1162 5.OE-03 6 1.2E-01 6.2E-04

1299 3.OE-03 6 1.4E-01 4.1E-04

1436 2.OE-03 6 1.5E-01 2.9E-04

1573 1.OE-03 6 1.5E-01 1.5E-04

1710 1.OE-03 6 1.6E-01 1.6E-04

1847 1.OE-03 5 1.7E-01 1.7E-04

2276 1.0E-03 5 2.OE-01 2.OE-04

Simulations with MAGIC Software Package

As mentioned earlier, time to abandonment calculations were conducted using the zone model

MAGIC. MAGIC is a fire two-zone model, which provides the capability of simulating the

development of a hot gas layer in rooms with and without mechanical ventilation systems. Key

2-245
inputs to MAGIC includes: 1) room geometry, 2) wall thickness and construction, 3)

specifications of the mechanical ventilation system, 4) fire size and 5) fuel properties.

The control room was modeled in MAGIC as a single room. The fire was located in the center

of the common control room area. Figure 3 illustrates the geometry as modeled in MAGIC.

Notice that the control room area was modeled as having a rectangular floor base with equivalent

floor area. Simulation times were 20 minutes.

Figure 3: Control room geometry as modeled in MAGIC

The following were considered when running MAGIC:

" Room size and construction: The control room area was modeled with an effective floor area

of 67' x 60' and a ceiling height of 23'.

" All wall materials were modeled as 2' thick concrete.

* Horizontal openings: As illustrated in Figure 3 above, the control room was modeled as

having one 3' x 6' open door.

* Mechanical ventilation: The mechanical ventilation system is modeled as a balanced

supply/exhaust system with a flow rate of 2.73 m3

/s. The room also has a smoke extraction

system with two vents, each extracting 3.7 m3/s. This system is manually activated by the

fire brigade.

* For the purpose of the simulation, it is assumed that the smoke extraction system operates

10 minutes after the fire starts. At this point, the normal system is turned off.

2-246
" Heat release rate profiles: The heat release rate profiles follow the guidance provided in

Appendices E & G of NUREG/CR-6850. That is, the peak heat release rates listed in

Tables E-6 and E-9 in NUREG/CR-6850 for electrical cabinets and transients respectively

were used. it was assumed that the growth profile is t

2 growing to a peak in approximately

12 minutes.

" Fuel Properties: Fuel was assumed to have a soot yield of 0.18.

Relevant outputs/Abandonment criteria

MAGIC creates one output file for each simulation. The output files contain the information

necessary for determining the time to abandonment. Specifically, the following outputs were

evaluated:

- hot gas layer temperature in the MCR area,

- hot gas layer height in the MCR area,

- Total heat flux to Target 1, and

- optical density in the MCR area.

Specific MAGIC inputs are included in the MAGIC input files. Figure 4 illustrates a snapshot of

a MAGIC simulation with and without mechanical ventilation. Notice that the simulation with no

mechanical ventilation suggests the development of a hot gas layer and flows moving out

through the open doors.

2-247
Figure 4: Pictorial representation of a MAGIC simulation of the control room fire

2-248
Session 12: Multi-Compartment Fire Analysis

2-249
Slide 1 Notes:

E1121 c~US.NRC C-= 11S1A1CH ItlStlUlT

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Task lic - Multi-Compartment Fire

Analysis

Joint RES/EPRI Fire PRA Workshop September 2008

Washington DC

A ACoIaboration of US. NRC Office of Nuclear Regulatory Research (RES) & Electtfc Power Research Institute (EPRI

Slide 2 Notes:

! MULTI-COMPARTMENT FIRES Objective

Fire scenarios involving multiple, interconnected or adjacent

fire compartments are analyzed in this part of Task 11.

* Fire propagation

* Smoke propagation

* A rare event in U.S. NPP fire experience

* Screening process

Fi- PRA Worshop, 200. Washfgtan DC [-, . Co~ boo dU.. NRC O2c] NlRgtoy o 

Task 110. -Mu-tC-,apairt relm Anabyst. R.. h IRESI 0 EdcPo.0rRO oh i "tPuf04)

2-250
Slide 3 Notes:

SMULTI-COMPARTMENT FIRES Overall Approach

Multi-compartment analysis is focused on screening of

potential scenarios before any detailed analysis is attempted.

- Single compartment analysis to be conducted before this step

- Reduce number of multi-compartment combinations

- Same analytical approach as in Detailed Fire Modeling

Fk. PRA W o s.. 2008. WtShhqo DC sW. A CO.8o,.00 d U .S NRC OWý ffNd RR. uA.R

TeOMI Ic . MuiMCOmp.tt•t Rti Anslyls - R--,h (fRE) & E.A•1c PoweftR.n-rh i.19 (EPRI)

Slide 4 Notes:

MULTI-COMPARTMENT FIRES Definitions

The following two terms are specifically defined for this part of

the analysis:

- Exposing Compartment. The compartment where fire ignition occurs

- Exposed Compartment: The compartments where fire from the

exposing compartment propagates to

Fire pRA Workshop, 2008, Washington DC S A CdIlbostl 0/AS, NRC Offieo/N ear ReAtor

Tas. 110. -MUl-Conp fm Fit Analysis R-0 tA ) & /etn Power Re..rh OnA. 5ER0

2-251
Slide 5 Notes:

! MULTI-COMPARTMENT FIRES Analysis Steps

The following steps define one possible approach for multicompartment fire risk analysis:

- Step 1.c: Exposing and Exposed Compartments Matrix

- Step 2.c: First Screening-Qualitative

- Step 3.c: Second Screening-Low Fire Load Exposing Compartments

- Step 4.c: Third Screening-Frequency of Occurrence

- Step 5.c: Fourth Screening-CDF Based

- Step 6.c: Detailed Analysis

- Step 7.c: Document the Analysis

Ft. PPA WoW, 2•008 2O W S, D c , A C o • o0 V U NRC 0Rk.4M N RD-tov

t.. I 1 1,on -f. lo,, tMe R n A tia Rýat. (RES) P- wosat. &oskhe SFP

Slide 6 Notes:

! MULTI-COMPARTMENT Step 1.c: Exposing and Exposed FIRESCompartments Matrix

Develop a matrix to identify all potential multi-compartment

fire scenarios that start with an exposing compartment and

propagate into a set of exposed compartments.

- Well defined pathways

- Means of propagation (i.e., hot gas, smoke, etc.)

- Special characteristics to be noted (e.g., self closing doors, fire

dampers and vents near the ceiling)

- More than one exposed compartment

- Supported by a walk-down

Fire PPA Workshcp, 2008, WBshington DC A C ofUS S.abomon NRC WO.e of Nciea RE-ua'o'y

Tm. 11, -Mui#-Compat Fie Analysis RX-) (DES) & SedtcPoweRes.,h 00t,4e (EPO

2-252
Slide 7 Notes:

! MULTI-COMPARTMENT FIRES Step 1.c: Exposing and Exposed Matrix (cont'd)

The following rules are suggested to identify multicompartment scenarios:

- Postulate only one barrier failure (e.g., door left open)

U Unless there is a clear reason to assume common cause failure of

* multiple barriers

- Assume minimal smoke damage

- Hot gas can travel to all physically possible exposed compartments

* For a large number of compartments open into each other, detailed

analysis may be warranted

Fiml PRA Wnwshop, 2008, Wus.ington m s ACobRCoRWU. NRC ODCice NRsaray flak lie. MuMRI.CorwslrntnF•mAnalyis R-nh (RES) &Elbttý,PoRýnReswh /liU, (tEPRO

2-253
Slide 8

!MULTI-COMPARTFIRES Step 1.c: Exposing and Exposed Matrix (cont'd)

Example:

# Exposing Compartment # Exposed Compartment # Path Comments

pi Name ID Name

1 9 SWG Access Room 1.1 10 Swtich Gear Room A 1.1.1 Door The door is 3-hr rated and normally closed

1.1.2 Opening Ventilation opening between rooms with

fusible link activated fire dampers.

1.2 11 Swtich Gear Room B 1.2.1 Door The door is 3-hr rated and normally closed

1.2.2 Opening Ventilation opening between rooms with

fusible link activated fire dampers.

1.3 - Stairway 1.3.1 Door The door is 3-hr rated and normally closed

2 4A RHR Room 2.1 4B AFW Pump Room 2.1.1 Door The door is 3-hr rated and normally closed

2.1.2 HVAC Duct There are two HVAC ducts with opening in

both compartments providing intake and

discharge

2.2 -- Stairway 2.2:1 Door The door is 3-hr rated and normally closed

3 4B AFW Pump Room 3.1 4A RHR Room 3.1.1 Door The door is 3-hr rated and normally closed

3.1.2 HVAC Duct There are two HVAC ducts with opening in

both compartments providing intake and

discharge

Fire PRA Workshop, 2008, Washington DC

Task 11c - Multi-Compartment Fire Analysis

i A Collaboration of U.S. NRC Office of Nuclear Regulatory S .................. j... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

2-254
SMULTI-COMPART Step 2.c: First Screen

The first screening of th

contents of the expose

The following criteria m

- The exposed comparti

components or cables

- The Fire PRA compon

compartment(s) are id

Fal PRA 1W5,*hw 2M5. Mai,*,Wa n DC

nak 11. -l.ff.Co.mp.ar008ins . AnaJysis

Slide 9 Notes:

MENT FIRES

ning - Qualitative

he scenarios can be based on the

d compartments.

nay be used:

ment(s) do not contain any Fire PRA

, or

ents and cables of the exposed

entical to those in the exposing compartment.

s;;l9. A A f-o S. Ný Wý &N, Rlslds

Slide 10 Notes:

! MULTI-COMPARTMENT FIRES Step 3.c: Second Screening-Low Fire Load

Exposing.compartments that do not include combustible

loading sufficient for generating a hot gas layer in any of the

exposed compartments can be screened out.

- Conservative HRR values

* Ignition sources with highest 98% HRR

* Add HRR of intervening combustibles

- Determine damaging HRR values

* Hand calculations

* Hot gas layer damage in exposed compartment

- Compare HRRs

Fin, PRA Wo•s, 2O8S, Washingt- DC - A -tn d U.S. NRC ORG di- f RoadWY

rTst 110 -MuI LComparn- Fire Analysis Resn, (RES) A VC 1 • - rch s88,-. (EPRI)

2-255
Slide 11 Notes:

MULTI-COMPARTMENT FIRES

Step 4.c: Third Screening-Occurrence Frequency

Scenario likelihood is established from the following three

parameters:

- Ignition frequency

- Combined severity factor and non-suppression probability

* HRR comparison (preceding step) can give the severity factor

* May assume PN, = 1.0

- Barrier failure probability

Fire PRA Wotho, 200M. Wasihkgfon - DC A COOaOOOU~n o'uS. NRC 2 0Nu ,48gua,

Task 11,c.Mu2.Comfpsrtron PFir Analysis R -ech (RES) & FJectdcPH p R-ses -2t1ute (EPR/)

Slide 12 Notes:

! MULTI-COMPARTMENT Step 4.c: Third Screening /Barrier FIRESFailure

Generally, data on barrier failure probability is sparse, and

what is available is subject to many limitations.

- Initial attempt may be based on a screening value

. May use Pr(barrier failure) = 0.1 for screening

- For scenarios that do not screen out, may use the following:

* For water curtain, use detection and suppression approach

* Verify that there are no plant-specific barrier failure problems

* Use the following generic barrier failure probabilities

- Type 1 - fire, security, and water tight doors - 7.4E-03

- Type 2 -fire and ventilation dampers - 2.7E-03

- Type 3 - penetration seals, fire walls - 1.2E-03

Fie PRA Wob0shop, 2008, -.50.9-m DC 2 A CSSo, U S N0 0 5 . .sAt,

T.55 11- -.Mu2IChpa,00.rt Fir. An-yal. R.5002(000) 80ete 0,Rssrc 2528a (02,00

2-256
Slide 13 Notes:

! MULTI-COMPARTMENT FIRES Step 5.c: Fourth Screening-CDF Based

Those scenarios that survive the preceding screening steps

may be screened based on their CDF.

- Assume all PRA components and cables of exposing and exposed

compartments are failed

- Estimate CCDP

- Use scenario frequency of preceding step

Fft PRA wa,*top 2008. WChUgto2 DC 13 ] A COSo r.IoO aWN NRC 0a &Nut. RWa-y

Tas tic -MURICon4arb.mt An*f f -N (RES) 4.0E PRo, Room Rt. (NEPRO

Slide 14 Notes:

MULTI-COMPARTMENT FIRES

Step 6.c: Detailed Analysis

Those scenarios that do not screen out in the preceding

steps may be analyzed using the same methods as for single

compartments.

- Same set of steps as in single compartment analysis

- Include target sets from exposed compartment(s)

F/rn PRA Wo.RWoR, 2W,0 Washi~gfa oC F,. 1 A Cchdrfcab ofU. NRC 00cR Of N~ar Re$uWaty

TasR tic. MuiR•,Co,- artet M)h/, = Re - (-RED) . FRR Ro am R Oti. (6ERf

2-257
Slide 15 Notes:

! MULTI-COMPARTMENT FIRES Concluding Remarks

Multi-compartment fire analysis should be performed to ensure completeness of the Fire PRA.

- Compartment partitioning process (Task 1) has a direct impact on

this task

- Develop a matrix of exposing and exposed compartments to ensure

completeness

- Screening analysis is necessary to limit the level of effort

- Barrier failure probabilities should be treated conservatively

- May have to revisit some of the partitioning definitions

Tas PR Vof * 2M fut•Cmpt me F DeAClt• (RS J cPwr emhm ER

2-258
Session 13: Seismic Fire Interaction

2-259
Slide I Notes:

*US.NRC ca=-I= IECHIC POWL lSRH(S9T

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Task 13: Seismic Fire Interactions

Joint RES/EPRI Public Workshop

September 2008

Washington DC

Afoi of U.S. NRC Oeo. of NuclearRegulatoy R..esarh (RES) A Eletric Power Resea. h Intitute (EPRI)

Slide 2 Notes:

Task 13 - Seismic Fire Interactions

Scope of this Task

Task 13 covers the Seismic Fire Interactions review

- You will find that little has changed compared to the guidance

available in the IPEEE days

- The review remains a qualitative, walk-down based approach to

identify and address potential vulnerabilities or weaknesses

- The procedure does not recommend any quantitative work in this

area

The main goal of the outlined methodology is to verify that the

the risk associated with seismically induced fires is low.

FiR PRA WW*SOop, 2008. W,ýOfh C F A C oAUs SofaoraLo, NRC o0 ofOmed aray Task 13: Seismic Pir InteM efons dh R1 (RES),& e -lwm -Res.Oh (EPRI)

2-260
Slide 3 Notes:

Task 13: Seismic Fire Interactions

Seismically Induced Fires

A severe seismic event may cause fires inside or outside an

NPP by damaging...

- Pipes and storage tanks containing flammable liquids or gases

- Electrical equipment

An EPRI study and NPPs experiencing earthquakes have

demonstrated that these events are rare.

F"b PRA Wrt. 20M, W.00bgto DC . a Co O S, lU, NRC OS WMCRWRF08IRy

Ths V M ., fllm F t . r, 0.1*408 (RES) 8.1*•t E° * 8 0 tEENS

Slide 4 Notes:

Task Background 13: Seismic Fire Interactions

* Seismic Fire Interactions originated with the Fire Risk

Scoping Study (NUREG/CR-5088, 1989)

* The conclusion of that study was:

"It would appear that this, is an issue which is more

easily corrected than quantified. A series of simple

steps was outlined which if implemented on a plant specific basis would significantly reduce the potential impact of such considerations."

This conclusion remains valid today.

FH. PRO Worshp, 2008, Washngf- DC s . Ccboraýo, - & 0.. NRC O o N08eaReg -- PROry

Task 13:- Pesi IfntrCons R*140 (RESt &8.08 e P *e 08 (FFR0

2-261
Slide 5 Notes:

Task 13: Seismic Fire Interactions

Key .Compartments

The review should focus on those compartments that house

equipment and cables needed to support post-seismic safe

shutdown

- Review your seismic-related procedures and identify key equipment

(components and cables) and any required manual actions

- To the extent possible, map equipment to compartments

- Identify the associated compartments and focus efforts on these

compartments

* Areas/compartments housing the key equipment (components and

cables)

Areas where a manual action takes place

* Access paths for manual actions

F#9 pPP WW*d~k 200, M$~ DhSoC F;; 57A ýMWa d I RCwdM .I.g,.y

Slide 6 Notes:

Task 13: Seismic Fire Interactions

Seismically-Induced Fires

* Potential sources:

- Unanchored electrical equipment such as where motion during

seismic event might cause a fire

- Unanchored gas cylinders

- Flammable gas piping

- Flammable liquid piping or storage tanks

* If any significant sources are identified, consider potential

plant modifications to minimize potential hazard.

FiR• FR Wor*shap, 200., Washington CC S 6 Cdiabonof UD NRC Office oNuCeRQgdatory

Tas0 13: Sesmitc Fin inNeuctons Re5r. (SES) & DTPcS* pn555.rcd 0562(E0R t 

2-262
Slide 7 Notes:

Task 13: Seismic Fire Interactions

Degradation of FP Systems and Features

- Review:

- General plant practice related to seismic restraints for fire

protection systems and features

- Installed systems and features and assess potential for seismicinduced failure

* Assess potential significance of system or feature failure to

post-seismic event operations.

* If any potential vulnerabilities are identified, consider fixes

to reduce likelihood of failure.

Fk PRA WoRNo. 2M08. W.IM.ton DC [ 7 A CNoabtaoo'U S NRC OA70 noO .R."tWy

UO 13: S.NR* R.r.Wl©os ruES) W0 , P4 e, 0ft- 0 (_0)

Slide 8 Notes:

! Task 13: Seismic Fire Interactions Spurious Detection Signals

* A seismic event will likely trigger activation of various fire

detection systems - especially smoke detectors

* Consider how the operators will respond to multiple fire

detection signals

- You can't ignore them even though many may be false

- Have you identified the issue in your response procedures?

- Have you (can you) prioritize your response based on the important

compartments?

* Consider potential procedural enhancements to recognize

and deal with this issue

Fl. PRA Wo,*R00, 2O06,8W8 '000000 DC.0 [C , A 00.0ab ,Rt S" NRC ° 0 R.Ou.00y

TasO 13: Oeismio 00. OntcOons Re0:h (RE0)& 0001-1.p ,R.0.000 00t0u. (EPP)X

2-263
Slide 9 Notes:

! Task Spurious 13: Suppression Seismic Fire Actuation/Release Interactions

* Review the fixed fire protection systems in key areas for the

potential that they might spuriously operate

- Got any of those mercury switches left?

- How about a non-seismic deluge valve?

- What happens if a sprinkler head is damaged or a pipe breaks?

- Are storage tanks for gaseous suppressants seismically robust?

* If any potential vulnerabilities are identified, consider fixes to

reduce likelihood of spurious suppressant release.

S A C (oRtE WUS NRC Ot dMA N .0 A• 8ýIO Fk. PRA WN*2•0. 2008, Wf-.ggoOC nd 13: S.sA R. tnt..d

Slide 10 Notes:

Task 13: Seismic Fire Interactions Manual Fire Fighting

* Access pathways to key areas - could something block the

path and are there alternative paths?

* Required fire fighting assets - will assets remain available

after an earthquake

- Especially fire water system and fire hoses

* Do post-seismic response procedures allow for manual fire

fighting needs and responsibilities

* If any potential vulnerabilities are identified, consider fixes

Fir. PRA WorkshOP, 2008, WMSJQoA DC d A Co/ ntof U.S. NRC OfiNe oNud. RegdflV

Ta.. 13: S.1i-l1 Inf. tn s RFl.e (RES a & r r.,.p R bl~ue (r~rJh (PR1)

2-264
Slide 11 Notes:

Task 13: Seismic Fire Interactions Summary

* Seismic fire interaction is considered a low risk phenomena

* NPP and other industry experiences partly verify this

premise

* A qualitative approach is suggested for verifying that plant

specific conditions confirm low risk notion

* Systemic or procedural upgrades are recommended for

identified potential vulnerabilities

FMr PRA Worsho, 208. Wshngton DC E =, A C-abotkf US. NRC OffC oNd R0gAMrC

Task 13: klsmlc Ph R.R... Intutions (RES) & e p• Rsh 55820 (EPRQ)

2-265

Conclusion

Part 1: Integration

3-1
Slide 1 Notes:

,*-.SNR mpei

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Integration, Lessons Learned and

Insights

Bijan Najafi, SAIC

Steve Nowten, SNL

Joint RES/EPRI Fire PRA Course

Sept. 29- Oct. 2, and Nov. 17-20, 2008

Bethesda, MD

I A Clbott, fU.S. -R Ofl.1--M~.1rR~golofyRN.oo (RES)& S 10088 P0,.,Rese8d1 hys08181 (EPRI)

Slide 2 Notes:

PART I

Integration

F-e PRA WOOW.- 208888010A 1668osNCON.M0oR~o

We. .o,(ses0.,8 8 0196 ____(,5 oe p'S 81,,(P,

3-2
Slide 3 Notes:

Integration

Modules

t"°enaoI I"rapblo¢uflt IPIantoperatorI

* Module 1: PRA/HRA - Post-fire plant response model, including systems, components and

operator manual actions (CCDP, CLERP)

* Module 2: Cable selection, circuit failure mode analysis

- Electrical response, embedded in the Post-fire plant response model

(Pd)

* Module 3: Fire analysis

- Fire hazard; ignition frequency, fire severity, fire growth,

detection/suppression (IF * SF * Pr,)

FýPRA VV~ 2008. &O#a20u. MD A c08M3u a U S O 000 0e00

ýfUODf Lýoo Lwmd Abd hOf8 - WS &j ,- ý ý M-0

3-3
Slide 4

Notes:

3-4
Slide 5

I Overview Structure Of (2) Fire PRA Process and Module

B

-etailed D Fire Scenario Analysis . I

iTASK9: DetailedCircuit Faikure sSnl oprmn

Analysis TASK 11: Detailed Fire Modeling

I~A- Single CnnmparnrnentI

I TASK 10: Ckcuit Faluee Mods & B Multi-Compartinent

Lkelihood Analysis C Main Control Roo.

esitkil An ,s El Fire Module

•1' PRA/HRA Module

TTASK 16: Fire PRA

Docu mention Circuits Module

Fire PRA WorkshIntegration, Lessons Learned and Insights ..Slide . 5 A Collaboration of U&S, NRC Office of Nuclear Regulatory

................................... Research (RES) & Electric Power Research Institute (EPRI)

Notes:

3-5
Part 2: Lessons Learned and Insights

3-6
Slide 6 Notes:

PART II

Lessons Learned and Insights to-date

on Use of

EPRI 1011989, NUREG/CR-6850

Fe PRA WoeddP', 2008 B.P•,'d" M"

nth n, Le Learned a nd Fidehtf Rf.r (IRES) & BeatPow, e ResWch U•tdvu (EPRI)

Slide 7 Notes:

! Lessons Learned and Insights Scope of this Module

* Demonstration .studies / Pilots

- Focus today is on NFPA-805 pilot plants and other "early adopters"

* FAQ process and methods-related topics

* General insights; Programmatic & Technical

* Path forward with EPRI 1011989, NUREG/CR-6850

Fire PRA Workshop, 2008, Bethesda, MO S A Cot-aheon oUS NaRC 0r dlNurRUlator

Integntion, Leasae L rnAd hnd Insights Re.eh (RES) & Elet-c Poer -esSAh )aesute (EPR/

3-7
Slide 8 Notes:

! Lessons Learned and Insights Demonstration/Pilot Studies

-The procedures were individually tested during development

-All the procedures worked, and seemed to be of reasonable

depth, scope, and clarity to make implementation practical

- First top-to-bottom testing as a full, consolidated, and

complete set ongoing by 805 pilots and other early adopters

Fi. PRA Wo .s~os 2008, 8h ,MD • A CdrsbO• C, d.S. NU- Z (NXAe R.Nu fly

IUmt*,. L.- L .ýn dInsghb #.d L eso sssS & s son s. R r W EP(o

Slide 9 Notes:

! Demonstration Lessons Learned /Pilot and Studies Insights (continued)

* Numerical results are being developed, but remain

preliminary

* The potential for "hidden surprises" was acknowledged from

the outset, and there have been some...

- Others likely remain to be discovered, and you may find them

* The NFPA-805 FAQ process is the primary mechanism

currently available to address application issues

- As a user, you should monitor the FAQ process

- FAQ resolutions may resolve your questions as well

We continue to seek user feedback and experience - the

procedures are intended to be "living documents" to at least

some extent

F~m PRO Wo,*ýs00, 200. Bothosda, MD A Co0bRtMn d U.S. N00N800

fntegra0in, Lsons Lesn.aWndlnslghb S ReearJ (RESt & UNCJt Pos R fsearhr e (EURO

3-8
Lessons Learned

Pilot Studies - Our E

Confirm that...

- It's Easy to get distrac

- If you want to re-basel

fire PRA - the objectiv

PRA would benefit

- -Work together with the

product is useful for Fi

* Get a team of the righ

do the job, e.g.:

- The PRA gurus may th

those with true electric

- You.NEED your teamt

plant operations, HRA,

Fn PRA IKibo, 2M05 f•f1t.Ad, MO

bMw.#ftm L-so Lý..nd endrioh.

Slide 10 Notes:

and Insights

"rly Experience Showed and Pilots

cted, e.g.:

ine Appendix R, do that first, then do your

es are NOT the same although the Fire

Appendix R re-baseline to ensure the final

re PRA purposes

t people with the right knowledge to

ink they know circuits, but you really need

al expertise

to include expertise in fire, systems, PRA,

and electrical circuits/analysis

Slide 11 Notes:

Lessons Learned and Insights

Frequently Asked Questions (FAQ)

* The NPFA-805 FAQ process is the primary vehicle for

feedback to EPRI TR 1011989, NUREG/CR-6850

- Managed by the NEI/NRC NFPA-805 task force and NRC/NRR

NFPA-805 team

* FAQs cover a range of topics and not all are related to the

fire PRA methodology

* FAQs come from various sources including the RES/EPRI

team, the 805 pilot plants, and other early adopters

F rePRA Worshlo, ZOOS, 2 nlhenda, MD

Int tln, L -on L.md and Insights Se A e Sn dUO. & 000 Offce n nlnnRe (EiRO

3-9
Slide 12 Notes:

! Frequently Lessons Learned Asked Questions and Insights (FAQ) (continued)

* To date 52 FAQs have been initiated

* Of these 52, 16 are related to implementation of EPRI TR-1011989,

NUREG/CR-6850

* Of these 16:

- 4 are closed (i.e., resolution complete and docketed)

- 12 are pending (i.e., resolution is not yet final)

Various stages from near complete to in the initial "problem statement" stage

* Caveat:

- Although a resolution may be complete and docketed, a FAQ still remains

"unofficial" until endorsed in a revision of Regulatory Guide 1.205 (either

directly, or by endorsing a NEI-04-02 revision that incorporates the FAQ)

FkU PRA Wt*&h•o. 200, Bethesda. MD A C-hbors~n dUS. NRC 0-S oNukr Regular/

Mnftunon L-or- L.eane and lInshet 55 S) ohe P- tte&na t,-- eB-u (E1R•)

Slide 13 Notes:

! Lessons Learned and Insights Frequently Asked Questions (FAQ) (cont)

* Fire PRA "Methodology" FAQs include

- Clarifications to existing guidance

- Filling in methodology "gaps"

- Refinements to existing approaches

- Revised guidance for specific aspects of the analysis

*14 of the 16 methodology FAQs are "fire" questions

- These FAQs cover a range of topics

* The other two are "electrical'" questions

- Spurious actuation dependency given multiple cables with HS

potential impacted by the same fire

- Hot short duration

Fire PRA WnRtkhop, 2008, Beftteda, MD A COn Ot U S. NRC Oe dNU .W R,7g4a

tn0gn.ton, (Aese L- ed and tr00ehb Ressnt (S) & F , pe Resort 1n00gC (EORt)

3-10
Slide 14 Notes:

! Lessons Learned and Insights Closed FAQs

* FAQ 06-0016: Electrical cabinet counting guidance

- Provides clarifying examples of "vertical section" counting guidance

* FAQ 06-0017: High Energy Arc Faults in electrical cabinets

- Provides clarifying guidance for counting cabinets in the context of

HEAF ignition frequency

- Provides a frequency split between low and medium voltage cabinets

- Clarifies treatment of HEAF in MCCs

* FAQ 06-018: Main control board (MCB) fires

- Clarifies definition of MCB (what to include, what to exclude)

- Clarifies direct link between model in Appendix L and the as-defined

MCB

Fk. PRA o*, 2W80 , Befthd, MD __Nou

tnftp•rio. Lm t Lw d and bfIghb 5 14 taa (RES) & 088 R e tf JEM) (88 R1

Slide 15 Notes:

L Closed essons FAQs Learned (continued) and Insights

FAQ 06-0031: Ignition source counting guidance

clarifications and extensions

- Bin 14 - Electric motors: clarifies guidance, provides for excluding

small motors of 5hp or less and totally enclosed motors.

- Bin 21 - Pumps: provides for excluding small sampling pumps, and

other pumps of 5hp or less

- Bin 23 - Transformers: provides for excluding dry transformers of

45KVA or less

- Bin 26 - Ventilation subsystems: clarifies that intent is to exclude

small subsystems powered by motors of 5hp or less (consistent with

electric motors bin 14)

F-. PRA Wokoý , 2008. BeThesda, MD * Cdkbnsdnn of US. NRC 088. ofl0 R.u.~ oty

In0eUIJOo, LamomS LWed and lnSlghta L . 8n RES) 4 fltdc Power 08h1f. (EPR)

3-11
Slide 16 Notes:

L In-process essons Learned FAQs and Insights

FAQ 07-0035: High energy arc faults in bus ducts

- Issue:

. Guidance document is silent on topic

- General approach to resolution:

* Acknowledge potential for such events (e.g., Diablo Canyon 5/2000)

* Provide plant wide frequency and counting/partitioning guidance

Provide zone of influence and scenario development guidance

- Status:

* FAQ resolution has been drafted and reviewed

• Final revisions in process

FV. PRA Woftoh, 2008, B.tO.'"dA. MONRC OHM o Nu RWWo

hntgeeos, Lns Cumed andInsight- . 515 A $C & 0 FhoM (PC Rese, (E-)

Slide 17 Notes:

SLessons Learned and Insights In-process FAQs (continued)

- FAQ 08-0042

- Issue:

- Guidance provides conflicting language regarding propagation of fire from

cabinets (Chapter 6 versus Appendix G)

- General approach to resolution:

* Clarify and expand definition of "well-sealed and robustly secured

cabinets" (which will not propagate fires)

- Status:

• FAQ resolution has been drafted and reviewed by RES/EPRI team

• Industry and NRC staff reviews pending.

Fire PRA Wotko., 2M.8. Bethesda, MD

W.te(r"of, Le.O- Leed eod InIgh.t _________ A Cd&t..Lb~d ((S. NRC DIke RM~ee'Regke~V ale. IL Rn.eth (wOo & EJedkPeoeResemmA lostNee (EPRO

3-12
Slide 18 Notes:

SLessons Learned and Insights In-process FAQs (continued)

FAQ 08-0043

- Issue:

* Guidance for placement of a cabinet fire (the source location) suggests

inspecting cabinet contents and placing fire at fuel location

* Applicants would prefer a 'one size" approach less conservative than

placing on top of cabinet that would not require internal inspection

- General approach to resolution:

* RES/EPRI teams are debating merits of general application of fire

protection SDP approach - place fire 1 foot below cabinet top (unless top

is unsealed or vented)

- Status:

* Team position has been drafted and is under review

* Staff final review pending

Fe PRA WoýMcnp, 208, Be"A-, MDA COt d U S NR C &NdaRR-y F eRse h (RES) & El5ti Powe ReCVnh 5fit- - (EPRIJ

Slide 19 Notes:

L In-process essons Learned FAQs (continued) and Insights

FAQ 08-0044

- Issue:

- Guidance for large oil spill and fire is generating conservative results

especially in the case of MFW pump fires (high frequency of large release

compared to experience base)

- General approach to resolution:

* Provide an alternative approach and revised tire frequencies for leaks

and spills from higher volume circulating oil/lubrication systems

- Status:

* General consensus that a revised treatment is appropriate and needed

* RES/EPRI team discussion of the specific resolution approach continues,

reviews ongoing

* NRC 805 team and industry 805 task force reviews pending

Fimr PRA Workhop, 2'08, Bnhsdfa, MD OACof ha US NRCO N Rguaol

lntegrtlnn, Le-ons Le-sed end insights S R -i Ch t (RES) • Eltns N po0 RC h in u (Eeng Ok

3-13
SLessons Learne In-process FAQs,

FAQ 08-0045

- Issue:

* Fire growth recomme

consideration of an in

generation of un-burn

- General approach to re

. No clear resolution ap

- Status:

* A problem statement

* FAQ. may be withdraw

fI PRA WoWtIst 0 BýtWh.S. MD

Slide 20 Notes:

d and Insights

'continued)

ndations for electrical cabinets does not include

cipient stage (e.g., pre-ignition heating and

ad pyrolysates which might be detected)

esolution:

proach has yet been developed

has been generated

Nn - not amenable to short-term solution

Slide 21 Notes:

Lessons Learned and Insights In-process FAQs (continued)

FAQ 08-0046

- Issue:

* Methodology provides no approach for crediting incipient fire detection

systems

- General approach to resolution:

. Develop an approach that would credit these systems

- Status:

* Initial drafts of a proposed approach are under discussion within the

RES/EPRI teams

* Work continues to try to establish a firm technical basis

* NRC staff and industry review pending

Fir. PRA Wowshop, 2008, Belheda, MD of US NRComN0I0 R0ua50y Integraton, Lessos LarneM anA Inslghts ISds2 R0~r. (ROS) ElCMc Potter Rssth insth•e (1PR00

3-14
Slide 22 Notes:

! In-process Lessons Learned FAQs (continued) and Insights

* FAQ 08-0047

- Issue:

* Guidance states that when more than one cable can cause the same

* spurious actuation you combine probabilities using "exclusive or"

* This assumes faults/effects are independent

- General approach to resolution:

* Consensus reached that "exclusive or" is not appropriate if faults are

dependent (e.g., a common power supply for both cables)

* Clarify treatment to determine and address dependency

- Status:

* Team draft has been completed

* Staff and final industry review pending,

FRi PRA WobrO*hW, 2505 Bhed,, MeD A o 0 V. a M o Itd R-..

IM.noa, L..non. L darnedfirtsI Bght S (RE2) & BI/Sc Po v h.R h t EPRQ

Slide 23 Notes:

SLessons Learned and Insights In-process FAQs (continued)

FAQ 08-0048

- Issue:

* Fire frequency analysis may not reflect industry trends (i.e., towards

reduced fire frequencies

- General approach to resolution:

* Work is under way within EPRI team to determine if statistically significant

fire frequency trends can be demonstrated

* Fire frequencies for one or more ignition source bins may be modified (up

or down depending on trends)

- Status:

* Work to date remains largely within the EPRI team

* Review/input by RES team pending

FiR PRO Wor*ksho. 2008. Bethesda, MD A S N N R y Integr~don, Lsson. Larned and Insights Ste2 RCd5h (E)&EeIctri phe e/u/hir&t(E

3-15
Slide 24 Notes:

! In-process Lessons Learned FAQs (continued) and Insights

FAQ 08-0049

- Issue:

The cable fire empirical spread model (tray-to-tray, stack-to-stack) has

been misapplied in pilot applications

• Reviewers concluded that misapplication resulted in very conservative

fire growth and risk results

- General approach to resolution:

. Clarify the bounds of the empirical model to avoid misapplication

- Status:

* Proposed resolution has recently completed final review within the RES

and EPRI teams

* Staff and industry final review pending

* Final revision, as needed, pending

- Note: as a follow-on, team plans to generate a new FAQ to address

broader needs relative to cable fire growth modeling

F- PRA Wodhl,. 2Mr, dBO.A, MD A U P I Ra 4- h n,qmf L -• L eý ,Wltdk3h-hts q/a°t~ ý RSd US"N ý ý Mc -EPrMgua ( 

Slide 25 Notes:

SLessons Learned and Insights In-process FAQs (continued)

FAQ 08-0050

- Issue:

* The fire non-suppression curves as cited as reflecting suppression

performance after fire brigade response time but a significant fraction of

the duration data used in curves includes brigade response time

* Fire brigade may not be getting'adequate credit for suppressing fires prior

to damage

- General approach to resolution:

* EPRI team has reviewed data and proposed an alternative set of nonsuppression curves that would include fire brigade response time

- Status:

• Work to date has largely been confined to EPRI team

* NRC team is currently reviewing proposed resolution

* Staff and industry reviews pending

Fire PRO WorSSoP. 2558. &15esda, MD F A Co d US. NRC SOre Nue{ Rg&OtaoV

Mfn red.o Lecc "nsghftsj C.reed rand ORereh (OES) & E-d-rc ow- R d n cO. (EPRO

3-16
Slide 26 Notes:

! In-process Lessons Learned FAQs (continued) and Insights

FAQ 08-0051

- Issue:

* The guidance does not provide a method for estimating the duration of a

* hot short once formed

* This could be a significant factor for certain types of plant equipment that

will return to a "fail safe" position if the hot short is removed

- General approach to resolution:

* Analyze the existing cable failure modes and effects test data to

determine if an adequate basis exists to establish hot short duration

distributions

- Status:

* Initial data analysis has been completed and results are under team

review

* NRC staff and industry review pending

wee PRA WblodW M0& Befe00.. MD Ass o S.NRC aý Oy

lnflt.Uz4 L.-l~lell L--. a M f F---T (RES) & S e PoerR -A - (0EPRI)

Slide 27 Notes:

! Lessons In-process Learned FAQs (continued) and Insights

FAQ 08-0052

- Issue:

* No guidance on fire growth times for transient fires

* Guidance not clear as to which non-suppression curve would apply to

transient fires in the MCR (i.e., transient curve or MCR curve)

- General approach to resolution:

* Review existing test data and develop guidance for transient fire growth

times

* Clarify non-suppression curve application for this case

- Status:

* Initial team position drafted and undergoing review within the teams

* Staff and industry reviews pending

Ffm PRA Workshop, 20, Behiesda, MO 2 A C bo,.1o o U.S. NRC W.0 &N~oeaRe~ousIRy

IneftglRon, Lesson Lan.edandlRsIight. Resh (RES) & EOeWrt FRost Rsssech wnos (EFRI)

3-17
! Lessons Learned Component Selection

* Resource intensive a

consideration of multi - ANS Fire PRA Standa

* Defines the scope of'

plant (system and opt - Ongoing discussions

* Fire PRA component

R and PRA compone

- New components who

* For MSO considerati

* For fire-specific opern

- Expect that you will wa

risk result

* NMPrI pilot follows th

consideration Re PRA w6M,*shW 2004 Bethesd. MD

ln emg.nUd. Laodss Le. 8 an.dd .ns/h

Slide 28 Notes:

and Insights

nd critical, for the most part due to

pie spurious operation (MSO)

rd is identifying requirements on MSOs

the Fire PRA as it relates to post-fire

erator) response re: instrumentation in NFPA 805 pilot program

list will be larger than your Appendix

nt list se omission will be non-conservative

Ons

ator manualactions (OMAs)

ant/need to consider others to get a realistic

he EPRI/NRC-RES method on MSO

28 Ahde a Ceoasno,, Wa NRC OSnfesotsxjRaosfl

(REd) d s008* P-,. R-.esCR ,na- (EPRO

Slide 29 Notes:

Lessons Learned and Insights

Cable Selection

Cable selection is probably the single biggest factor that

will drive your resource requirements

- The burden comes largely with the need to trace selected cables

- You also need an accessible cable database, and constructing

such a database from your existing system may not be so easy

- This is going to depend a lot on the depth of your cable tracing

and the nature of your current tracking system

Exercise judgment

- You may initially want to trace all your cables, but that may not be

the best choice - you are takingon quite a job at most plants

- Take advantage of the iterative approaches to cable tracing

Fie PRA Wor*hop, 2008, Bethesda, MD OA toha USNRCOflkaaN~taar Rs9Waoy Integ 80r Iati on, tie aseLed and flnsighSlts 2 Rea C h (RamfotS) & R Officepower R 0h insfut atpy

3-18
! Lessons Learned Circuit Analysis

* Circuit analysis need

* Compared to cable tra

less resource intensiv

participation of key pe

* The procedure providi

been drawn from past

- Make use of those opti

- Go after the "bang for t

not risk important

Fr PRA Wotrow. 20W8. Btheda, MD infentmon, L-eSP L-dedh.10W•lns

Slide 30 Notes:

and Insights

not be.a huge burden

acing, circuit analysis should be far

e - although it does require

rsonnel (the electrical guru)

es various approaches that have

practice and experience

ons!

he buck" circuits and "take the hit" when it is

s~ ~ A CAIMO1gkn dU . NRC ai oft.Rýf.AtoO

Resnh (RES) & EtriN PýoRwsnrcN f (CePR) 6ePR 

Slide 31 Notes:

! Lessons Learned and Insights Fire Ignition Frequency and Fire Modeling

* Understand the scope of work of Tasks 1, 6, 8 and 11

- One walkdown effort for collecting information for all the tasks

- Use of a relational database for organizing and analyzing data is

recommended

- It is recommended that Task 8, Scoping Fire Modeling be conducted

with Task 6, Fire Ignition Frequencies or Task 11, Detailed Fire Modeling

* Fire modeling in single compartments

- Hand calculations will suffice for many cases, but more sophisticated

modeling (e.g., compartment fire models) also has a place

- Create fire modeling drawing packages. These are room layout drawings

with ignition sources and Fire PRA targets highlighted.

* Fire modeling in the main control room

- Fire zone or field models are necessary

- Will require detailed system analysis and HRA

- Smoke removal system can significantly impact abandonment and risk

Firm PRA WoJ*Ahop, 2008. BMNhSa, MD A -w -USooo, U N RC Ofins WNudewReg1elq

Inftgreton, Lessons Leared end Insights R.N1 e0. (REN) I --CRic p- R -esearc -Nsie fEPRI)

3-19
Part 3: Perspective

3-20
Slide 1 Notes:

U.S.'NRC El-rJei EL[CIVIC I FWH

EPRI/NRC-RES FIRE PRA

METHODOLOGY

Module 111-2: Perspective

Ken Canavan - EPRI

J.S. Hyslop - RES

Joint EPRI/RES Fire PRA Course

September 29 - October 2, & November 17-20, 2008

Bethesda, MD

A Co-abontion of U.S. NRC Office oftNuclear Regulatory Research (RES) & EJocic PoFrn ResearCh Institute (EPRO

Slide 2 Notes:

!On The Requantification Project

* A consensus methodology for Fire PRA that is facilitating

implementation of risk-informed fire protection

* Remains the best available method to estimate fire risk &

obtain insights

* Guidance is producing greater agreement among technical

experts

* Much activity ongoing in NFPA 805 FAQ program due to

fire PRAs being performed during transition

Roe PRA Wdwl , 2008, Befs sa MO 2 a b, IRcS US R-f.. Modul. lR-Z: PWar.Reuw .Raa REt&EC Ps.R a., 440(P

3-21
Slide 3 Notes:

! Continued Cooperation

* We established a framework for future research cooperation

- Quality of work and positive technical reviews pave the way for

continued cooperation

* The cooperation under the MOU is continuing

- Fire Model User's Guide

- Fire Human Reliability Analysis (HRA)

- Fire Low Power and Shutdown

- Others....

Fi- PRA Wo 2008 M8Ao, Berhnda . MD _ A Cobortin t UNRC a OMIce oa r RVU.4R0

Y

Module 1.2: P•8 6V ReMh (RES) & E•dlc PawnR~ ach 00tR.- t (EpRIO

3-22
Appendices

Appendix A: Questions Asked in Module 3 Sessions

NRC Disclaimer: Appendix A is intended solely for use as part of a training tool. No portion

represents NRC conclusions or Regulatory Positions, and should not be interpreted as such.

Session 1: Plant Partitioning

QUESTION

Slide 21: Who conducts these plant walkdowns? Are they done in-house or by contractors, for

example?

RESPONSE

All of the people you mentioned are part of this effort. Contractors, utility people, co-ops, recent

graduates, everyone. The level of experience and knowledge needed to do this must not be

taken for granted.

Session 2: Fire Ignition Frequency

QUESTION

Presentation b, page 6: still don't get how to consider WL.

RESPONSE

I basically try to start fresh and say how I'm going to-count the equipment, and once you make

that decision, this becomes simpler. For example, if it's very easy for you to assign equipment

to one unit or another, which is not always the case, then you just count them by unit and forget

about this stuff. It's all 1. The reason I'm saying that it's not all that easy is because if we're

trying to count equipment by unit, where one panel is assigned to unit 1 and another to unit 2.

Then, you go to a room and there is a panel with no label. You don't know what it is, so your

ideal situation breaks down. So, this helps you count things. Then, you bring into the picture

the question of whether or not the equipment is shared. At this point, you can do what Marty

said, like counting half of a pump. Usually, in the control room, it can be discerned what

corresponds to unit 1 or unit 2, and either you can split them in half or assign the board to one

unit. If there is the case of a problem that is swinging, it may be better just to count it as half. If

you are clear on how you are counting, then this does not pose a problem; either count it as half

if it's shared, or count it as one.

If, on the other hand, you have a shared control room and you counted only one unit, without

even considering the other unit, then the ignition sources for that room are twice what you have

counted. So the contribution for the fire source is twice the ignition frequency. If you have a

generic frequency for a single unit but have twice the units, then you have to double it. My

advice, therefore, is to consider how and what you are counting in the interest of being

systematic. If you're just doing a localized analysis for the control room, you can just count

A-1
something as one unit, but if you have a shared room, you need to add that multiplier because

you are not counting the rest otherwise. (The answer to B is 2.)

The key to this is that the frequency in 6-1 applies to the cabinet in the unit that you are

analyzing. That is the count on which Francisco is focusing. That frequency is the total

frequency of fire ignition for a specific type of component. If you count that accurately as best

you can, then in a room where the other unit is in there also, you can do what I suggested and

you will be fine. The point is that this whole thing is unit based and that any new components

must have units that match the existing components.

QUESTION

Page 6: Would this be equivalent to saying that a fire that starts in unit 2's control board is

guaranteed to spread to unit I 's board?

RESPONSE

No. It is not necessarily guaranteed, but it is a possible contributor. You're establishing the

frequency of fire within that room. Any fire. Actually, we're trying not to count it twice. That's

what we need to be careful with, double-counting. This is equivalent to counting the two units,

such that where you have 400 panels instead of 800, to simply double all the frequencies.

When you do that, you will get the right weighting factors. Whatever you do, prevent that double

counting, because the frequencies are per unit, and you have two units. Make sure you don't

double-count.

QUESTION

Page 6: I think you hit the nail on the head that if you're doing the per-component count for the

entire space, that you wouldn't need the sign there, a WL of 2, if you count every source in

there. If you know what's in unit I but are unsure of what's in unit 2, but you know that it has a

similar configuration, then you could assume a WL of 2 for that space, that time in your analysis,

right?

RESPONSE

If you count everything, and you counted it well, you will get the weighting factors correctly.

QUESTION

Presentation A, slide 22: Suppose they're done horizontally?

RESPONSE

Again, you need to define your own reference cabinet and compare that against the reference

cabinet. Define vertical segments of some kind and count it that way. You see, what it comes

down to is that that specific cabinet vs. the rest of the cabinets in the plant that are within that

group; all of the frequencies from 6-1 will be assigned to all of them. You must ask yourself how

much of the frequency you will assign to this cabinet from another cabinet. If you come up with

an internally consistent scheme, this will give you the best approach for use. All of your

cabinets are horizontally divided, right? All of them are. Each horizontal division will be

assigned one count. It comes down to pro-rating your total frequency to each item.

A-2
Session 3: Scoping Fire Modeling

A BRIEF REVIEW

Reviewing the risk equation.

Points to lambda sub G; This is the generic frequency. Where does it come from? Inaudible

answer. Points to Wsub is-i. What is this? Where is it coming from? Walkdowns, and counts

of ignition sources. This is a split fraction of ignition sources. What is this? Points to severity

factor. Where is it coming from? Heat release rate. Somebody can tell me how we come up

with the severity factor? Where does it come from? HRR that would damage your target. We

assign a distribution to each ignition source, right? We found the HRR that would damage the

target, found that value in the distribution, and the area under the curve to the right is, what

Dean said, 2% or less, then you can screen it. We say that it is unlikely that the fire will get that

big.

QUESTION

Slide 13: So we screen ignition SOURCES if the critical value is higher than the 98th percentile?

RESPONSE

Yes. The only cautionary note is that the critical value should come only from the ignition

source. If you have trays above the ignition source, the HRR may not come only from the

ignition source. That may be one you have to further analyze to see what the cable trays would

do. Only an isolated ignition source, incapable of propagating, would be able to be screened.

This admittedly limits its applicability, given some of the complex geometries that we have, but

that's the way to use it.

QUESTION

Slide 13: How do you determine whether or not an ignition source will screen?

RESPONSE

Let's do two cases. If, above your cabinet, you have a stack of cable trays, and you start a fire;

if the only cable you care about is in a tray remote from the ignition source, then you can screen

the source. If, however, you have the ability to propagate a fire up, you can not simply screen

the fire, even if the actual target is remote from the fire.

QUESTION

Slide 7: How would you organize your list of design fires?

RESPONSE

I would strongly suggest a section, when you are dealing with either scoping fire modeling or

detailed fire modeling, that clearly says "these are the types of fires I have, and I'm going to use

this generic values, or I have these plant-specific values," and you just get it over with in a clear

A-3
section that you can reference, writing justifications for what your damage criteria are. Keep the

HRRs in a centralized place where you know where your justifications are. That should work

fine.

QUESTION

Slide 7: What conduit do you use in this fire modeling?

RESPONSE

The conduit is the same as the type of cable that you have inside. That was thermoset cable in

a conduit, so we used 625.

QUESTION

Slide 13: Do you treat transient fires in the same probabilistic manner as other ignition sources,

by saying where they are most likely to be located?

RESPONSE

What Walt is telling me is that this FAQ will need to be more detailed in addressing types of

panels and transient fires. It is also silent on when to put a transient fire. People love to talk

about trash bags. Where do you place a trash can fire? All of these are questions that are not

addressed in 6850. Hopefully this FAQ will address it.

QUESTION

Slide 13: What I'm hearing is that one thing being accounted for in the FAQ is that these

correlations have not been developed for use in multi-dimensional cabinet fires. It seems that

this is not an appropriate application for this model. A fire inside of an enclosure has an

obstructed plume, resulting in a three-dimensional fire, rather than a two-dimensional fire. Now,

there are ways to get around that. When I'm putting on my peer review pack, or I'm doing the

analysis myself, what, when you're talking about justification, has been done in the way of

discussion about whether these are really applicable to these cables and, if you recognize that

they aren't, what documentation do you need to provide to be able to say "we handled this in a

manner that deals conservatively with the answer to that question"?

RESPONSE

You're right in all your points. For fires inside cabinets, you're right, these are not applicable,

and I think our treatment has been "forget about the cabinet, we just put our fire there."

Hopefully the effects of the cabinet walls will be to the benefit of those targets, so not having it

adds that conservative approach.

QUESTION

You could say that we measured the heat release rates and determined how much energy is

being released there, and that the distribution of this release is unimportant because the plumes

have different amounts of energy. You can postulate a single plume coming out. Like you said,

I'm not saying that this is a show-stopper, but what I would do is go back to the FAQ and say

"what's the bounding analysis where I can locate my fire?" The answer to your analysis may not

A-4
be favorable, and that's what I'm reading in this FAQ; that this answer is too conservative, and

that we want something a little better, but we don't have the means to really do that. At this

point, I don't think there are enough test data or analysis calculations.

RESPONSE

In a way, that's why 6850 was silent, because this task is somewhat beyond the state of the art.

That was the task of these documents, state of the art. I agree with that argument. I'm telling

you that so far, once you assume this fire, the guidance is to use an unobstructed plume up to

where you encounter this obstruction. In my example, I intentionally included intervening trays

that are not targets and advised you to screen them if you have obstructions.

QUESTION

Looking at some of these analyses, though, if you just plug and chug this, I will have to flag it

and ask you to show me why this limitation is valid. There may be a valid reason, though, if you

take that HRR and situate it atop the cabinet. You may not have a decent argument if it is

situated on the floor. It is by no means a showstopper, but have there been discussions about

this issue? When you get to the end of this, it could be a showstopper.

RESPONSE

There is either limited guidance or questions being raised on the FAQ. The only point I want to

make about the FAQ is that its focus is very narrow, and is not intended to expand into a

research-wide paper. Another point to be made is that some of the arguments used in this may

come on risk terms, rather than on fire modeling terms. They may choose to be very

conservative, rather than using the best inputs, because they can accept the more conservative

plant impacts.

QUESTION

So then these equations are justified by guesses about conservatism?

RESPONSE

I'm not saying that that's the justification. I am saying that the equations we have are what we

have, not something new developed for the nuclear industry or something, and that there are

documents and training describing its use and limitations. Analysts are using them within the

limitations. I suggested that not all of the justifications will be on a fire modeling basis. There

are other issues that provide these checks, not just because of the use of the model. In a risk

analysis, the justification will not simply be the use of this model. By the time you know what the

impact is, you must also know the cables involved, what the impact is, how the circuit behaves,

and many other things involved in it.

Are you suggesting that the models we have are not conservative? Because the models can be

quite conservative, we hope. Are you suggesting that we are guiding people in the wrong

direction?

A-5
QUESTION

I don't think that there's sufficient guidance to tell people how to take correlations developed

from two-dimensional pool fires and three-dimensional wood grids and apply them to an

electrical cabinet. What you're saying with the lack of guidance here is that it's okay to do that.

I don't see anything here that says "electrical cabinets: beware, because this is how these

empirical correlations have been developed." They're outliers.

RESPONSE

I don't see that when we suggest "view the fire and forget about these cabinet walls" we are

misapplying the correlation.

QUESTION

I don't think that you are. I think that one solution would be to do a bounding analysis where

you find the HRR and find a reasonable representation of the area of the fire, and that will be all

I've got. What I see in the FAQ is that this tends to be the most conservative approach, and

we're asking for a less conservative approach. I don't think we're there yet, I don't think that we

have the fundamentals to put forth this less conservative approach. That is guidance that could

be provided to people, by saying "look, we understand this stuff doesn't work, but here's how

you get around it."

RESPONSE

It's not that it doesn't work, it just yields a very conservative answer.

QUESTION

We don't know if it yields a conservative answer.

RESPONSE

That's the impression I'm getting, is that they're getting very short time periods, and that's giving

them headaches.

QUESTION

We never validated the cabinet fires with the correlations. That's never been done. It's just

been in applications.

RESPONSE

Then what you're suggesting is that what we have in the guidance is not conservative. That's

the key here. What we have here is the important element that we have to fault on the side of

the conservative.

QUESTION

The bounding analysis places the fire on the exterior of the cabinet, and thus far, I fail to see this

addressed in the FAQ.

A-6
RESPONSE

Any reading that you're doing on this FAQ is not final yet. The FAQ is still in process, and these

concerns that you raised are being considered. FAQ is a misleading term; it's actually only one

question. This is currently under analysis. I am the first one to agree with you; from an

experimental, analytical perspective, we may not have the tools to address it with math. That's

not the only place in risk analysis where this is an issue.

QUESTION

But it has to be addressed, I think. There is a workaround, and it just needs to be put forth so

that everybody knows exactly how we're getting around the limitation. All of these correlations

were verified, right?

RESPONSE

Well, verified by experiment. That's how it's done.

QUESTION

But in the DMD study, if / remember correctly, you screened those out because they weren't the

correct equipment. You can't use that in your correlation because it was essentially the junk

data from another experiment. You did it for other well-known, well-characterized fires.

RESPONSE

We have to be careful here. I agree with you in that these correlations are applicable if you

have a fire inside a panel and you want to consider this panel, walls, and the effect that the

cabinet will have. Do we have a correlation for that? Do we have guidance on how to do that?

No. People report a heat release rate and assume there is no cabinet. In this case, if there are

no obstructions, we have said "yes, use this plume correlation". Would I want to see further

research and a model to account for that? Probably yes. Do we have it? No, that's why it's not

here.

QUESTION

But then specifically, how do you justify the use of the correlations this case?

RESPONSE

By assuming no cabinet. Is there an argument that yes, you actually have a cabinet and aren't

accounting for it? Of course.

QUESTION

So that's an assumption and the engineering validates these assumptions, and so, to me, the

best guidance would be to take the equipment fire and measure that heat release rate, and then

place it at the top of the cabinet as the bounding analysis.

A-7
RESPONSE

That's fine. That's what Walt says that his inspectors are doing, and I know plants are doing

that in some cases.

RESPONSE

I think that people who are doing these analyses need to understand that this is merely a

workaround to do this.

QUESTION

Why isn't fire modeling used every time? Wouldn't that help to evaluate each scenario in

context?

RESPONSE

The general approach in PRA is that you start with several failures. Rather than postulating no

damage, you start with fires that damage everything. From there, you make reductions. When

you apply fire modeling, you do so with the goal of proving that the target is undamaged,

because this disproves the initial assumption. You start assuming all these failures. If you have

high-risk, sharpen your pencils and see what you can get. It is in this reduction that you start

being less conservative because you're not killing everything, but within the application, your

conservatism is built in, and hopefully, the way you use these models is on the conservative

end, given that they are not the exact geometries present in each nuclear power plant scenario.

When we were doing the validation work, this is a point we raised. To get validation for every

single nuclear power plant scenario is probably impractical in the near future, due to all of the

geometries that can be observed in different plants. This is part of the state of the audience.

Session 6: Damage Criteria

QUESTION

Slide 3: How were the cables tested? Did they short and that caused the ignition?

RESPONSE

Well, it's just cables under a big flame. Those tests were trying to figure out the probabilities

and how this circuit behaves. So, yes, the cable is exposed to either a plume or flames.

QUESTION

Was there a documented pilot, a point where the cable ignited each time?

RESPONSE

Once the experimenters observed a short, the cable shortly thereafter ignited and this was the

pilot you were talking about.

A-8
Session 7: Detailed Fire Modeling and Single

Compartment Fire Scenarios

QUESTION

Slide 10: Can you set boundaries for ignition by saying "this is the closest ignition source,

therefore since it doesn't catch, all of the others won't ignite also"?

RESPONSE

Why, yes. With the right tools like a well-organized database that can talk to the PRA, you can

play games like failing all of the conduits and see if you can use that approach to screen the

cable trays for something. That sounds easier than what it is if you don't have the right tools,

because when it's not hooked up, this becomes a manual process. But once it is, and you

understand your ID systems of how trays and conduits are labeled, then you can do cable

database events on a larger scale in order to screen things. I have seen databases where the

cable and raceways would have so-called "rooms" within compartments, based on column lines,

because the cable and raceway database was based on these column lines. So we defined

these rooms within the fire compartments. Since everything was so well-labeled, we could go

and say "fail a room" in that compartment. That would be a portion of it defined by column lines

where all the conduits and trays there could be set with trays associated to them. This would

allow us to see where we really needed to go and sharpen our pencils. I stress that this sounds

simpler than what it is, because it requires a well-structured database with good data. In plants

that have that, it is straightforward by postulating fires once you have your ignition sources. But

if it takes some building to do and some data cleanup, then so be it.

QUESTION

If you use CFAST, you don't have to verify and validate your model, do you?

RESPONSE

That's our intent. We want it to be such that if you use CFAST within reasonable bounds of

what was V&Ved, then that's your V&V. But a V&V has its own limitations, a set of extrema that

were set for it, so not every single feature in CFAST was V&Ved. The sprinkler feature, for

example, lacks the verification process applied to the cable fire modeling within CFAST. The

way it works is that we classify the results, and say "this kind of overestimates", or says that one

part is right on target. Our intent, to the best extent possible, is that if you use CFAST, you don't

have to write an appendix explaining your validation. I agree with you, that before the V&V, we

would have to write an explanation of the model we were choosing, which is why we have this

suggestion now: it is very convenient.

QUESTION

If you use CFAST, do you need to have it V&Ved on each computer? Is it workstation-specific,

like in DOE?

A-9
RESPONSE

I will let higher pay grades answer that question. I don't know.

Session 8: Detection and Suppresion

QUESTION

Slide 15: Where is the data for the BWR containment? Four of them are not directed. Wouldn't

we then use the PWR containment?

RESPONSE

I would say so. We didn't have data for the BWR containment to develop this. We knew that

there were a few that were not. There are four in this country, but we only thought there was

one. I guess we were off.

QUESTION

Does this assume a standpipe with a hose is available, or a fire extinguisher, or perhaps a mix?

RESPONSE

This is the deal with these cu-rves. We have the data from the fire events database, and some

of that data lists time (fire duration), or time to suppression, or both. So a subset of the data that

we use for the frequency has that kind of information. In addition, we only use data after 1980,

which is when appendix R kicked in. That's the data we use for these curves. Admittedly, not

all of the data has this information. When available, we use the time to suppression, but if the

duration was available and not suppression we will use the duration. This is part of the FAQ,

saying "well, those duration times are longer than the actual time to suppression". By the way,

the Browns Ferry fire was listed in order of minutes that they finally decided to use water after

hours of trying to use extinguishers. You have to be careful with those numbers. The bottom

line is that if the suppression was available, we picked that number. If not, then if the duration

was available, we picked that number. That may be a limitation of this. I'm talking now about a

subset of the data, post-1 980, and data that had either suppression or duration available, and

then we started excluding events that were suppressed by fixed systems, or self-extinguished.

So all of this is basically someone with an extinguisher or the fire brigade coming. These are

the events that made it to these curves, and with those events we developed this thing.

QUESTION

So for anything other than a brigade we don't use this time as a factor in the previous chart?

RESPONSE

Wrong. Like I was telling him, even for the activation of the sprinkler system, you need to

calculate the time for that activation.

A-10
QUESTION

The suppression probability you gave on slide 9: this is the probability of non-suppression?

RESPONSE

No, this is the probability of failure of the system. If you go back to the event tree, the PNS is

the sum of the non-suppression branches. When I'm crediting a smoke detection system, I

would put here the probability of failure (the split fraction) for the smoke detection system.

These are just probabilities of failure to put in these branches, but it is not the aggregate

probability of non-suppression. Those numbers in slide 9 are inputs to the event tree.

QUESTION

The curve shown here is only manual?

RESPONSE

Yes, only for the suppression probability for the fire brigade. There are more curves, and one of

the longest ones is the high-energy arcing faults. In this one, the quickest one to suppress was

the cable fire, which took only about ten minutes. You see that you very quickly go to very low

probabilities of the system.

QUESTION

Is there a curve for automatic suppression as well?

RESPONSE

No. The automatic suppression numbers will come out of the event tree when you do the same

thing. This is the same in table format, and this is the curve, so if you have a lambda, that

would be this mean here, and you stick it in and get this probability as a function of time.

QUESTION

Slide 20: Is your fire brigade response time just the time it takes them to get there?

RESPONSE

Well, it should be the time to start suppression activities. We usually go through the real

records of things within the plant, through all of your fire compartments in task 1, but places

close to it, and average drill records, and come up with numbers.

QUESTION

So if I have a damage time of 15 minutes and a brigade response time of 15 minutes,...

RESPONSE

The brigade fails. I was doing work in one international plant, and asked for the brigade drill

records, and they were all very good (-5 minutes), but then I tried to find out what was going on,

A-11
and the drill was always to the same place, and they knew where the fire was. They would say "oh, gosh. We have a fire in that room. Perhaps, you know, if you want, you can go and fight it

or something." If every week you go to the same place, they start becoming very, very good.

They don't have an addressable fire detection system, so when the alarm sounds they don't

know where it is, so for the drill they tell them where to go. This doesn't really represent the real

story. I have been in plants here, not to draw comparisons, but when I go through them, some

of them are very detailed, with times for everything on reports for each drill, and we pick out of

that the time to start the suppression activities. I put that as input data in my rooms tables,

where I have time to brigade response, and this becomes the time input to the event tree.

QUESTION

To take it a step further, if the damage time is longer than the response time, is there a

suppression time you add on top of the response time?

RESPONSE

No. If you can start suppression activities in 13 minutes and the damage time is 15, then you go

to your curve for 2 minutes and see numbers very close to failure. That assumes, of course,

that the fire brigade immediately begins doing the correct thing, rather than just wandering

around.

Session 9: Special Fire Models Part 1

QUESTION

Slide 8: Why are the units for the bench scale HRR given as flux?

RESPONSE

The bench scale is a small piece of material that you subject to heat flux and measure its HRR.

They express that HRR per unit area, and then we multiply it by total area to get the total

answer in kW. In this case, it is the area of the cable that is burning.

QUESTION

I know you mentioned qualified and non-qualified, what makes a cable qualified?

RESPONSE

It's just that 383 flame spread rate, whether or not it can propagate. It's not exactly the same,

but there are two conditions: qualified and non-qualified, just like thermoset and thermoplastic

materials. The best description of a thermoset cable vs a thermoplastic cable, as I heard from

MARK SALLEY, is that a thermoplastic just melts and drips, and the insulation falls. The

thermoset is like a hot dog that you leave on the grill on the 4 th of July, in that it just chars

around and the insulation doesn't fall, it just remains there. Unqualified and qualified comes

from the IEEE test, where we pass or fail that test. We kind of use thermoset / thermoplastic to

mean qualified / unqualified, even though that's not really what it means. But this PVC is clearly

thermoplastic. Some of the others are thermoset. You would need to decide on a number, and

A-12
this is all we have. There is a NIST report on this, and the NIST report has the most guidance.

The SFPE handbook has a condensed version, which is essentially the same thing as what is

shown in the slides, and 1805 has somewhere in the middle a discussion of where this is

coming from.

QUESTION

Slide 14: How far apart were the trays when you saw the fires jump between them?

RESPONSE

1 to 2 feet apart. Definitely not 10 feet.

QUESTION

Slide 15: If a plant uses some computational fluid dynamics and fire models, do they match this

model? If I built a model of that room and ran the calculations that you suggested here, would it

realistically match the expected results and propagate?

RESPONSE

Permit me to answer your inquiry in two parts.

Will it do some propagation? Absolutely.

The other part of your answer, a rather political topic, is that these models have not been

experimentally verified, and we don't have input parameters for the model, to V&V it. Even if we

take the experiments that were used for it and put it in a model, we would not have the

properties of the cables and other inputs that a fire modeler would need to say "this is V&V".

That's why we have it this way, and we say "go put it in a CFD code and see what it does",

because we don't have properties.

QUESTION

Why do you expect a disconnect between the model and the experiment?

RESPONSE

Obviously, some of the variables are not valid for it. But I have seen simulations of fires like

this, and there is no question that the fire jumps all over the place. My own opinion, by looking

at those simulations and these experiments, is that definitely this happens, and until we have

more data or better properties, we are not ready to go into those calculations, but at the same

time, I am not ready to say that propagation will not happen. I mean, models show that, for

whatever properties you put in, and experiments show it, for whatever experimental conditions

you have. I am being careful in my answer, because that is the discussion we have been

having.

QUESTION

Is there a stated limitation in how far, when you get outside of the test parameters, that you can

apply this model?

A-13
RESPONSE

The configuration of the test is described there.

QUESTION

Slide 19: When you say "segmented", you're talking about bus bars that are bolted together,

rather than what we call bus ducts, which essentially consist of concrete holes with cables

running through them.

RESPONSE

Actually, you can screen those, because it's only one piece of a cable that goes from one side

to the other with no junction points, right? FAQ allows you to screen it.

QUESTION

Wouldn't it be much better if you abandon the control room and go to the backup where your

probability of success is much higher?

RESPONSE

Yeah.

QUESTION

Why would you even try and stay in a place even if the temp of 85 degrees? Isn't the probability

of making a mistake 50% or higher?

RESPONSE

I am finding the probability that at these temperatures the operator cannot even be there, risk

analysis says that if there is a fire big enough, the operator should leave because this might be

their only chance, it is going to raise the risk if you stay under these conditions that are slightly

less than this limit, It is going to raise the risk than if you abandon the control room and shut the

plan down from elsewhere. You are penalizing yourself.

QUESTION

Are they just giving you a limit where you can't stay in the control room from the fire analysis

side? You got to take what they are doing and reintegrate it back into the model. One must

establish the appropriate abandonment criteria on when you are going to leave versus when

you going to stay. I am just saying that you start weighing how well are you're weighing your

leave the room methodology versus staying in the control room.

RESPONSE

I believe that people will want to learn how to improve their smoke purge techniques among

other things before they would want to worry about shutdown methodology. Fuel will burn fast,

and the creation of smoke will be rapid. But to be completely honest, most of these control room

A-14
monitors have to act on instinct because there is nobody in the background that tells you exactly

what to do in fires such as these.

QUESTION

Should we expect any procedures that are below the levels than the ones that were included in

this presentation, such as ones below the ultimate shutdown methodology? What we are

learning as of now is the steps that we should take in these situations and what is the allowable

time a operator should stay in the control room, From that information, it seems that we can

determine the realistic criteria for abandoning a control room and we can also consider the

shape factor and likelihood of making special actions.

RESPONSE

Not usually based on specific fire conditions they are more specific on what Walter was talking

about, I lose some of her ability and I usually take positions and waiting for judgments from the

operators you went and that might mean that people can stay and some in the control and

others do their own things. If you get to this stage, forget about the control, you are out of it.

Session 10: Special Fire Models Part 2

QUESTION

Slide 8: In the case of these fires, should you postulate a plant trip?

RESPONSE

What else is failing besides the trip? An extreme example is an RHR pump room fire. If you're

testing the RHR pump and the motor catches fire, will the plant trip? Most likely not. Of course,

the shift super may panic and say "shut down the plant", but there's no reason for them to lower

the power level and start a shutdown. You could argue that some of these events are a part of

the internal event, something that other people have already modeled, because a plant trip can

happen for many causes, including this one. You need to be careful how you do this, in order to

ensure that anything else that could be affected is not. If you can convince yourself that nothing

else is being affected by it, then you can say that it is a part of the failure probability that the

internal events people already considered.

QUESTION

Slide 8: When you look at the nature of these analyses, does it make sense that they would not

be a non-threatening fire? The data tells you something, but when you actually look at the

component, does it make sense that there's something about the way that the exciters are put

together that your fires are always hot and bright, because there's nothing to burn around them?

RESPONSE

That's exactly what I'm suggesting. Don't take this word and say "because evidence is confined

every time, therefore there's no need to worry"; you should look into the exciter and see if

there's anything nearby that is on the fire PRA component list. If it's on that list, you should look

A-15
at it carefully and see if it can be affected or not. This will come up again when we discuss the

catastrophic failures.

QUESTION

Slide 14: How do you resolve the fire size of the hydrogen formulas? I don't see a formula here.

RESPONSE

We didn't provide you a formula there. We have references. If you need the flame length, there

are formulas to find it, found in appendix N. I would suggest that you assume everything in that

room is destroyed, and if you can't screen that, then you should use these formulas. If the room

is huge, then use a smaller zone, but if it's a small room (which is typically where I find the

hydrogen piping), then assume everything is gone. If you can't screen that, then use the

appendix N formulas.

QUESTION

Slide 14: For battery fires, did fires result in structural damage to the buildings?

RESPONSE

The pictures I've seen have been in non-nuclear environments. In a nuclear plant, typical

battery rooms are inside buildings and they're well-established. They're in isolated rooms with

rated fire walls and ceilings. But the ones I'm familiar with were on the outside of another

building with a regular frame-type construction.

QUESTION

Slide 14: Have you ever encountered any catastrophic hydrogen deflagrations?

RESPONSE

I think the majority of the events in nuclear plants have been deflagrations. I don't remember

any detonations in the nuclear events, because the quantity generally is small. The large

quantity releases have been outside, where the relief valve has vented and created a hydrogen

fire on top of the hydrogen storage tank and created a large fire. In this case, the fire brigade

has correctly said "okay, we're not going to put it out, just let it burn itself out". By the way,

hydrogen flame (I think) is not visible.

Session 11: Main Control Room Fire Analysis

QUESTION

Why would analyze the fire impact on the farthest element from the postulated ignition source?

Wouldn't it screen more efficiently if you addressed the closest element?

A-16
RESPONSE

I wouldn't pick the farthest one, I'd pick the closest. That's exactly what I'm saying. You need

to be careful to see what set you're selecting. You will select the minimal selection that does

your damage.

QUESTION

Are you trying to say that you want to find the scenarios that could take out all aux feedwater

pumps? Or is there an exercise up front that will select those components you think you can

seek, so if I was going in looking at aux feedwater pumps, will I look for those things that will

take out all aux feed and measure those?

RESPONSE

In principle, you should look at every possible combination of these controls and

instrumentation. Obviously, that's an impossible task, so minimal cutsets is one idea, albeit

imperfect, because often times you don't have a perfect minimal cutest. You may have a partial

minimal cutset, so you basically need to pass judgment to see which areas are the most

important. Actually, it's a spatial exercise. You're basically going through the panel and

imagining a glob of fire of different dimensions moving about and around and affecting things.

QUESTION

As per the chart, I will take auxiliary feedwater and measure the distance to main feedwater,

with the assumption of no intervening barriers. Do we retroactively account for that?

RESPONSE

Not unless there is a very clear separation, a perfect wall. Cabinet walls can be considered

perfect walls, so long as there is no air gap. Imagine two cabinets put next to one another: a

perfect wall. Then, we give you a fifteen-minute credit in the methodology. Follow the

associated guidelines where they are listed. The main control board is no exception, although it

is generally open in the back. That opening has associated options with it, like half-walls, or

channels coming in, where things are put through. Some of them are completely open, with

spaghetti of wiring in the back well within sight.

QUESTION

If you postulate this type of fire, you discount the possibility that some of these elements with

potentially massive ramifications (very large CCDP) will be affected by the postulated fires.

RESPONSE

In this case, you can not say "I don't care", because you need to be very specific which pump

you will pick. You need to measure that distance. It may be difficult to establish the very fine

resolution, saying that one will be affected and not another. I would not recommend it. If things

are so close to one another, it is unrealistic to say that the fire will hit one element and not the

one next to it. The best thing to do is to form your list of possible fire events and then examine

all of those for which you think the CCDP will be significant. Significant CCDP in this world is

probably anything above .01. Anything above this number probably has some contribution.

A-17
QUESTION

What about a fire in the back of the control board? Something that affects the wiring?

RESPONSE

This method includes damage to the wiring. I have seen cases where people have chosen to

be so thorough as to walk it down and note where things cross from one part to another. That

raises another important point. If you have two elements separated by a certain large distance,

but whose wiring comes together in a small area of the control board, then a fire necessary to

take out both elements is not the large fire that affects the distance of separation, but rather a

fire only large enough to damage the control board at the point of contact, large enough only to

affect the distance that the wires are separated. The presumption is that the fire happens in the

back of the control board, or underneath.

QUESTION

What are some possible fire scenarios in this case? Where could the fire come from?

RESPONSE

Shorts, relays, smoking; there are some events inside panels that start with circuit guards.

Some start in the wires. I think it has happened internally within wires, although usually this

stems from a short somewhere else in the plant with a side effect of overheating within the

panel.

Let me recap. By doing this exercise, you effectively are also analyzing everything in the

immediate back of the panel that serves the front panel. Now if you have another back panel

with its own instruments and devices back there, you treat it as an electrical cabinet. This does

not change the exercise, though, in that you still walk the cabinet down and say "I care about

this part because it has a high CCDP".

QUESTION

Is there an indication that they're relying on their damage temperature for MCR abandonment

higher than 200 F?

RESPONSE

In the control room, usually some cables and sensitive electronics will be damaged below this

temperature. That can happen even with a fire that requires abandonment. This does not

assume that the entire room reaches a temperature of 200 F, just the gas layer at the top. If the

board is at a lower temperature, the room can still be tenable. When I have done these

analyses, I have seen that the HVAC in the MCR becomes a very significant factor that should

be included in your fire model. You may not even develop a hot gas layer, because the rate of

smoke removed from the room may be higher than the rate of smoke produced. Of course, the

HVAC systems are also subject-to failure, which can be represented in the same way as any

other component, with a probability of failure. I have seen plants with detailed procedures for

smoke purge. It is a mode, clearly defined, with operator guidance on usage. Push a button,

and a certain fan starts the smoke purge. There areothers that do not have such specific

requirements; the only options are normal operation and emergency mode, which is designed to

A-18
contend with such things as radiation as well as fire. If smoke purge is not clearly defined, then

it is more of a challenge. I have seen others that it is there, but for some reason, it is behind a

plate that makes it completely inaccessible during emergency conditions. They knew the

procedure, and there was certainly a way to make it automatic, but it was completely

counterintuitive.

Session 12: Multi-Compartment Fire Analysis

QUESTION

Slide 2: Spreading that you speak of here is just the gas and not the flame?

RESPONSE

Unless you have a direct line of sight for the radiation effects of the flame, you should take the

gas into consideration, but generally what we have in mind is that a very hot gas forms under

the ceiling, and it moves out. There are situations where there is a complete opening between

rooms, and this task is to do a screening analysis in a stepwise way to arrive at specific

scenarios that merit a more detailed analysis. You can appreciate that we could easily have a

very large combination of compartments that are adjacent to one another, and would

communicate with one another. Effectively, you must consider all combinations of rooms and

screen them out.

QUESTION

Slide 10: In this case, will you include all of the fuel in the room, not just the burning cabinet?

RESPONSE

Yes. Add the intervening combustibles when considering your multi-compartment fire.

QUESTION

Slide 11: When calculating all of the combustibles in the room, how do you add the transient

combustibles?

RESPONSE

We have a distribution for the transients, there is a 98 percentile HRR for the transients. We

recommend you use the worst-case fire you have in the room, and see if you can do damage

next door. In this step, something less than the worst case could do the damage, so this gives

you a severity factor, and also in this step, you must consider the probability of failure of a

certain fire barrier if it is required as a means of egress.

QUESTION

Slide 14: Do I need to subtract (1 - the barrier probability) from the other analysis that I did? In

the other analysis, we examined the potential for damage to the walls of the compartment

during a fire, so do I need to examine this scenario when assessing the probability that the

flame will spread?

A-19
RESPONSE

In principle, yes. But I think the impact will probably be insignificant.

QUESTION

If you can not screen out a fire spreading to a second compartment, do you then use that

second compartment as a source for the third compartment?

RESPONSE

Yes, you follow the same procedure that you followed for a single compartment analysis, but

then in this case the new target set is based on the elements in the new room. At this point, do

the same analysis that was done for a single analysis.

QUESTION

Could this lead to a domino effect, where rooms concatenate to form an extreme fire? In

practice, how does the fire brigade play into all of this?

RESPONSE

The detailed analysis addresses this. In this task, the multi-compartment analysis is only

screening-level analysis. This merely eliminates some scenarios and arrives at some others

that can not be eliminated, and then applies the detailed analysis for only that subset.

QUESTION

In your experience, how readily do you see individual rooms that fail to screen?

RESPONSE

Very many of these rooms will screen, making multi-compartment fires rather unlikely. You

need to consider barrier failure probabilities. The key is that the most important discriminator

will be the things that are failing in the second room. In other words, the CCDP will play a very

significant role in all of this. This is one area that requires a great deal of judgment. Over the

years, some plants involve fire zones, and some have no walls. Some have 20 feet on the floor

and say "this is my separation", with cable databases and documents all identifying this

distinction. They find it very difficult to redefine everything and remap all the cables in the

database. What I have commented on is that if you put fires in those boundaries and figure out

very quickly what your targets there are, and in those areas, place fires and check the

ramifications. One noteworthy exclusion is addressing what to do with oil. You could make

such a big fire that it is difficult to screen. You then need to decide which oil fire size you will

use, something that is not clearly defined in 6850. This is one thing that requires

documentation.

A-20
Session 13: Seismic Fire Interactions

QUESTION

Can you stay in a room that is on fire with temperatures rising to 90 degrees Celsius?

RESPONSE

If it gets to that temperature, that best course of action is just to abandon the room.

QUESTION

Would you be able to do anything within the control room once temperatures reaches these

extreme conditions?

RESPONSE

Yeah, you will be able to do things at these temperatures. But it is known that smoke that is

coming from the fire will affect your sight as well as your ability to breathe, so it will be assumed

when the first signs of a fire are witnessed, you are geared up and you have your breathing

equipment on.

QUESTION

A limitation of a 0.4 meter radius to see what is around you during an intense fire gives very low

visibility to do anything. Usually, control room operators are about 6-8ft away from the actual

control board. What should operators do in these situations?

RESPONSE

I mean, even with breathing equipment and everything I am not suggesting that you will have all

the crew doing everything that they suppose to do. I am talking about a fire accident and we are

just trying to find out where definitely they really have can't really do anything else in that room.

Everyone who is in this vicinity should be equipped with equipment in order to protect

themselves for the short time to evacuate the premises or do their specified duties.

QUESTION

At 95 degrees Celsius, aren't those temperatures where most people will gain 2nd degree burns

in a matter of 10 min?

RESPONSE

Yes they are, but we aspect our staff to be fully and properly geared up.

QUESTION

Do operator success probabilities change with room tenability? Obviously, they can not effect

changes within the control room after it has been abandoned, but does performance change

over time while the room is burning?

A-21
RESPONSE

One of the things that I think wasn't fully translated is if you assume that this operator stay in

this control room at these conditions, there are significant changes on the performance shaping

factor on the success of the operator. We are assuming that they are suited up as well as other

things to keep them safe during a fire. Those operators are sweating and their success rates are

low. I mean you got a high probability at play here for their actions within the main control room.

QUESTION

.Do you know the location of the switches that transfer the controls are?

RESPONSE

The switches are always located outside of the control room.

A Brief Review: by Mardy Kazarians

Here is my version of it. If you have an incident at all plants to the tune of about once every ten

years, your CDF is to the tune of a serious incident at one plant about once every 500000 years.

So to go from an incident every decade to a CDF of about 1 in 500,000 is a large step. I am not

saying that the basis for a CDF is weak, but merely that it requires a very solid basis.

In order to achieve this, we had to develop a frequency for ignition sources. We multiplied this

ignition frequency by a whole bunch of parameters, which became the fire scenario frequency.

We then multiplied this by a CCDP, something that came from the PRA model.

There is something wedged in between, which is the circuit analysis. This is not a trivial part!

The circuit analysis wedges between the fire scenario frequency and the CCDP because it may

identify events that are probabilistic. If we ignore the probabilities on that one, it affects the

CCDP, but sometimes we look at circuits and say "it probably won't happen, but here's the

likelihood that it will." That is wedged in between the scenario frequency and the CCDP. The

circuit analysis is a very important part of fire risk analysis for several reasons. The weakness

of a NPP is really in the cables that run from one place to another, because they are bunched

together. Common cause failure happens because they are bunched together and one fire can

affect many elements. Cables are part of a circuit, so understanding how circuits work is

important because the control circuit can cause failures that are not part of the risk model, like a

spurious actuation. Not all circuit failures can do that, so an understanding of how it can happen

is very important.

Our focus was completely on the fire frequency. We established the ignition frequency based

on component type. We also said that fire is a localized phenomenon, so we will focus on

compartments, a convenient way of looking at it. Ultimately, we will look at fire scenarios.

Thus, the way we should think about this is by starting with a very specific item or device, and

propagate that fire and its effects onto other items. This is the fire scenario, but it is too much

work at the beginning. In order to have a complete analysis without doing an excessive amount

of work, we use fire compartments and base our analysis on the compartments. We then take

this component type as an identifier for our ignition frequency and say that it is the same for all

components in the plant of that type.

A-22
We then need to multiply this by a factor that will correct it, to make it specific to either a certain

device, or to all possible ignition sources within a compartment. This is the ignition source

weighting factor. I don't want to talk about location factors, because this is the multi-unit factor,

but that is something you may wish to consider if you want to do a multi-unit analysis. This

establishes the initial fire. Now we must say that this fire must be strong enough, because not

all fires are strong enough to damage each item. Smaller fires can damage these components,

but they will take a very long time. A very strong fire is also possible from here, that can

damage these components quickly, so the discrimination between fires that can damage these

components quickly is the non-suppression probability. I can have a spectrum of severities of

the fire, and if it is medium strength, there is more time to suppress the fire than if I have an

extremely strong fire. It is an integral of all possible severities. We showed you how to do this,

and that there is a range of HRRs based on a gamma distribution. Based on the gamma

distribution, we showed you how to calculate the propagation rate to the targets, to establish the

time to damage, and then we also talked about how to establish the probability of nonsuppression based on location-specific features. If this event is a welding and cutting related

event, then we have a prompt detection and probability of prompt suppression. If it is a

component fire, then will the automatic systems come on? How long will it take the fire brigade

to show up? With this, we have established a scenario frequency, and this entire thing will be

multiplied with the CCDP and other things.

This is a summary of the parts we have discussed. Obviously, some of the parts are pretty

complicated, and the methodology behind it is very, very complicated. Effectively, we will use

relatively simplistic models to model what happens in nature. That basically gives you an

overview of what we tried to cover in the past few days.

A-23

Appendix B: Reference Tables and Figures

B-1
Table 1

Fire Frequency Bins and Generic Frequencies

Ignition Source Generic Split Fractions for Fire Type

ID Location (Equipment Type) Mode Freq

(per rx yr) Electrical Oil Transient Hotwork Hydrogen HEAF1

1 Battery Room Batteries All 7.5E-04 1.0 0 0 0 0 0

2 Containment (PWR) Reactor Coolant Pump Power 6.1E-03 0.14 0.86 0 0 0 0

3 Containment (PWR) Transients and Hotwork Power 2.OE-03 0 0 0.44 0.56 0 0

4 Control Room Main Control Board All 2.5E-03 1.0 0 0 0 0 0

5 Control/Aux/Reactor Cable fires caused by Power 1.6E-03 0 0 0 1.0 0 0

Building welding and cutting

6 Control/Aux/Reactor Transient fires caused by Power 9.7E-03 0 0 0 1.0 0 0

Building welding and cutting

7 Control/Aux/Reactor Transients Power 3.9E-03 0 0 1.0 0 0 0

Building

8 Diesel Generator Room Diesel Generators All 2.1E-02 0.16 0.84 0 0 0 0

9 Plant-Wide Components Air Compressors All 2.4E-03 0.83 0.17 0 0 0 0

10 Plant-Wide Components Battery Chargers All 1.8E-03 1.0 0 0 0 0 0

11 Plant-Wide Components Cable fires caused by Power 2.OE-03 0 0 0 1.0 0 0

welding and cutting

12 Plant-Wide Components Cable Run (Self-ignited cable All 4.4E-03 1.0 0 0 0 0 0

fires)

13 Plant-Wide Components Dryers All 2.6E-03 0 0 1.0 0 0 0

14 Plant-Wide Components Electric Motors All 4.6E-03 1.0 0 0 0 0 0

B-2
Table 6-1

Fire Frequency Bins and Generic Frequencies (Continued)

Ignition Source Generic Split Fractions for Fire Type

ID Location (Equipment Type) Mode Freq

(per rx yr) Electrical Oil Transient Hotwork Hydrogen HEAF 1

15 Plant-Wide Components Electrical Cabinets All 4.5E-02 1.0 0 0 0 0 0

16 Plant-Wide Components High Energy Arcing Faults1 All 1..5E-03 0 0 0 0 0 1.0

17 Plant-Wide Components Hydrogen Tanks All 1.7E-03 0 0 0 0 1.0 0

18 Plant-Wide Components Junction Boxes All 1.9E-03 1.0 0 0 0 0 0

19 Plant-Wide Components Misc. Hydrogen Fires All 2.5E-03 0 0 0 0 1.0 0

20 Plant-Wide Components Off-gas/H2 Recombiner Power 4.4E-02 0 0 0 0 1.0 0

(BWR)

21 Plant-Wide Components Pumps All 2.1E-02 0.54 0.46 0 0 0 0

22 Plant-Wide Components RPS MG Sets Power 1.6E-03 1.0 0 0 0 0 0

23a Plant-Wide Components Transformers (Oil filled) 0 1.0 0 0 0 0 All 9.9E-03

23b Plant-Wide Components Transformers (Dry) 1.0 0 0 0 0 0

24 Plant-Wide Components Transient fires caused by Power 4.9E-03 0 0 0 1.0 0 0

welding and cutting

B-3
Table 6-1

Fire Frequency Bins and Generic Frequencies (Continued)

Ignition Source Generic Split Fractions for Fire Type ID Locati Inon n oreMode Freq

(Equipment Type) o perrx yrElectrical Oil Transient Hotwork Hydrogen HEAF1

25 Plant-Wide Transients Power 9.9E-03 0 0 1.0 0 0 0

Components

26 Plant-Wide Ventilation Subsystems All 7,4E-03 0.95 0.05 0 0 0 0

Components

27 Transformer Yard Transformer - Catastrophic Power 6.0E-03 1 ;03 0 0 0 0

28 Transformer Yard Transformer - Non Catastrophic& Power i.2E-02 1.02 0 0 0 0

29 TransformerYard Yard transformers (Others) Power 2.2E-03 1.0 0 0 0 0 0

30 Turbine Building Boiler All i.1E-03 0 1.0 0 0 0 0

31 Turbine Building Cab-le fires caused by welding Power 1.6E-03 0 0 0 1.0 0 0

and cutting

32 Turbine Building Main FeedwaterPumps Power i.3E-02 0.11 0.89 0 0 0 0

33 Turbine Building Turbine Generator Excitor Power 3.9E-03 1".0 0 0 0 0 0

34 Turbine Building Turbine Generator Hydrogen Power 6.5E-03 0 0 0 0 1.0 0

35 Turbine Building Turbine Generator Oil Power 9;5E-03 0 1.0 0 0 0 0

36 Turbine Building Transient fires caused by welding Power 8.2E-03 0 0 0 1.0 0 0

and cutting

37 Turbine Building Transients Power 8.5E-03 0 0 1.0 0 0 0

1. See Appendix M for a deecdpticn of high-energy arcing fault (HEAF) fires.

2. See Section 6.5.6 below fora defnition.

3. The event should be considered either as an elecltical or oil fire, whichever yields the vorst consequences.

B-4
Table 2

Description of Transient Fire Influencing Factors

Influencing No (0) Low (1) Medium (3) High (10) Very High

Factor (50)

Maintenance Maintenance Small Average Large number Should be

activities number of number of of (PM)/(CM) assigned to

during power PM/CM work PM/CM work work orders plant areas

operation are orders orders. compared to that may

precluded by compared to the average experience

design. the average number of significantly

number of work orders more

work orders for a typical (PM)/(CM)

for a typical compartment. work orders

compartment. compared to

the average

number of

work orders

for a typical

compartment.

Occupancy Entrance to Compartment Compartments Continuously Not applicable

the with low foot not occupied

compartment traffic or out continuously compartment.

is not of general occupied, but

possible traffic path. with regular

during plant foot traffic.

operation.

Storage Entrance to Compartment Compartments Compartments Not applicable

the where no where all where

compartment combustible/ combustible/ combustible/

is not flammable flammable flammable

possible materials are material is materials may

during plant stored. stored in closed sometimes be

operation. containers brought in and

placed in left in either

dedicated fire- open

safe cabinets, containers for

a short time or

in a closed

container, but

outside a

dedicated firesafe cabinet

for an

extended time.

B-5
From Page 6-24 of NUREG/CR-6850

For general transients (i.e., Bins 3, 7, 25, and 37), the following equation should be used to

establish the ignition source weighting factor:

.WGT,J,L = (nm,J,L + no,J,L + ns,J,L)/NGT,L

NGT,L = YX (nm,i,L + no, i,L + ns, i,L)

(summed over i, all compartments of location L).

where:

nm,J,L = Maintenance influence factor rating of compartment J of location L,

no,J,L = Occupancy influence factor rating of compartment J of location L, and

ns,J,L = Storage influence factor rating of compartment J of location L.

In the case of transient fires caused by welding and cutting (i.e., Bins 6, 24, and 36), the

following equation should be used:

WWC,J,L = nm,j/Nwc

Nwc = Y nm,i,L

(summed over i, all the compartments of location L).

For cablefires caused by welding and cutting (i.e., Bins 5, 11, and 31), the following

equation should be used:

WCF,J = nm,j WCable,J /NCF

NCF = Y- nm,i,L WCable,i

(summed over i, all compartments of location L),

where:

WCable, i = Cable load of compartment i, based on the ratio of quantity of cables in

compartment i over the total quantity of cables in the location.

B-6
Table 3

List of Heat Release Rate Distributions

HRR Gamma

Case Ignition Source kW (Btu/s) Distribution Reference

75th 98th ax

1 Vertical cabinets with qualified cable, fire 69 211 0.84 59.3 Table G-1

limited to one cable bundle (65) (200) (0.83) (56.6)

2 Vertical cabinets with qualified cable, fire 211 702 0.7 216 Table G-1

in more than one cable bundle (200) (665) (0.7) (204)

3 Vertical cabinets with unqualified cable, 90 211 1.6 41.5 Table G-1

fire limited to one cable bundle (85) (200) (1.6) (39.5)

4 Vertical cabinets with unqualified cable, 232 464 2.6 67.8 Table G-1

fire in more than one cable bundle closed (220) (440) (2.6) (64.3)

doors

5 Vertical cabinets with unqualified cable, 232 1002 0.46 386 Table G-1

fire in more than one cable bundle open (220) (950) (0.45) (366)

doors

6 Pumps (electrical fires) 69 211 0.84 59.3 Table G-1

(65) (200) (0.83) (56.6)

7 Motors 32 69 2.0 11.7 Table G-1

(30L (65) (2.0) (11.1)

8 Transient Combustibles 142 317 1.8 57.4 Section G-4

(135) (300) (1.9) (53.7)

Table 4

Discretized

Cable, Fire

Distribution for Case 1 Heat Release

Limited to One Cable Bundle)

Rate (Vertical Cabinets with Qualified

Heat Release Rate - kW (Btu/s) Severity Factor Bin

Lower Upper Point Value (Pi)

1 0 (0) 26 (25) 11 (10.5) 0.446

2 26 (25) 53 (50) 38 (36) 0.219

3 53 (50) 79 (75) 64 (61) 0.129

4 79 (75) 106 (100) 92 (87) 0.078

5 106 (100) 132 (125) 118 (112) 0.048

6 132 (125) 158 (150) 145 (137) 0.030

7 158 (150) 185 (175) 171 (162) 0.019

8 185 (175) 211 (200) 197 (187) 0.012

9 211 (200) 237 (225) 224 (212) 0.007

10 237 (225) 264 (250) 250 (237) 0.005

11 264 (250) 290 (275) 276 (262) 0.003

12 290 (275) 317 (300) 303 (287) 0.002

13 317 (300) 343 (325) 329 (312) 0.001

14 343 (325) 369 (350) 356 (337) 0.001

15 369 (350) Infinity 427 (405) 0.001

B-7
Table 5

Discretized Distribution for Case 2 Heat Release Rate (Vertical Cabinets with Qualified

Cable, Fire in more than One Cable Bundle)

Heat Release Rate - kW (Btu/s)

Bin Severity Factor

(Pi) Lower Upper Point Value

1 0 (0) 90 (85) 34 (32.7) 0.506

2 90 (85) 179 (170) 130 (123) 0.202

3 179 (170) 269 (255) 221 (209) 0.113

4 269 (255) 359 (340) 310 (294) 0.067

5 359 (340) 448 (425) 400 (379) 0.041

6 448 (425) 538 (510) 490 (464) 0.026

7 538 (510) 628 (595) 579 (549) 0.016

8 628 (595) 717 (680) 669 (634) 0.010

9 717 (680) 807 (765) 759 (719) 0.006

10 807 (765) 897 (850) 848 (804) 0.004

11 897 (850) 986 (935) 938 (889) 0.003

12 986 (935) 1076 (1020) 1028 (974) 0.002

13 1076 (1020) 1166 (1105) 1118 (1060) 0.001

14 1166 (1105) 1255 (1190) 1208 (1145) 0.001

15 1255 (1190) Infinity 1462 (1386) 0.001

B-8
Table 6

Discretized Distribution for Case 3 Heat Release Rate

Unqualified Cable, Fire Limited to One Cable Bundle)

(Vertical Cabinets with

Heat Release Rate - kW (Btu/s)

Bin Severity Factor

(Pi)

Lower Upper Point Value

1 0 (0) 26 (25) 15 (14.2) 0.227

2 26 (25) 53 (50) 39 (37) 0.261

3 53 (50) 79 (75) 65 (62) 0.192

4 79 (75) 106 (100) 92 (87) 0.126

5 106 (100) 132 (125) 118 (112) 0.079

6 132 (125) 158 (150) 143 (136) 0.048

7 158 (150) 185 (175) 170 (161) 0.028

8 185 (175) 211 (200) 196 (186) 0.016

9 211 (200) 237 (225) 223 (211) 0.010

10 237 (225) 264 (250) 249 (236) 0.005

11 264 (250) 290 (275) 275 (261) 0.003

12 290 (275) 317 (300) 302 (286) 0.002

13 317 (300) 343 (325) 328 (311) 0.001

14 343 (325) 369 (350) 354 (336) 0.001

15 369 (350) Infinity 414 (392) 0.001

B-9
Table 7

Discretized Distribution for Case 4 Heat Release Rate (Vertical Cabinets with

Unqualified Cable, Fire in more than One Cable Bundle Closed Doors)

Heat Release Rate - kW (Btu/s)

Bin Severity Factor

(Pi) Lower Upper Point Value

1 0 (0) 53 (50) 36 (34) 0.082

2 53 (50) 106 (100) 80 (76) 0.213

3 106 (100) 158 (150) 131 (124) 0.224

4 158 (150) 211 (200) 184 (174) 0.177

5 211 (200) 264 (250) 235 (223) 0.122

6 264 (250) 317 (300) 288 (273) 0.077

7 317 (300) 369 (350) 341 (323) 0.046

8 369 (350) 422 (400) 394 (373) 0.027

9 422 (400) 475 (450) 446 (423) 0.015

10 475 (450) 528 (500) 499 (473) 0.008

11 528 (500) 580 (550) 552 (523) 0.004

12 580 (550) 633 (600) 603 (572) 0.002

13 633 (600) 686 (650) 656 (622) 0.001

14 686 (650) 739 (700) 709 (672) 0.001

15 739 (700) Infinity 816 (773) 0.001

B-I0
Table 8

Discretized Distribution for Case 5 Heat Release Rate (Vertical Cabinets with

Unqualified Cable, Fire in more than One Cable Bundle Open Doors)

Heat Release Rate - kW (Btu/s)

Bin Severity Factor

(Pi) Lower Upper Point Value

1 0 (0) 137 (130) 42 (39.5) 0.638

2 137 (130) 274 (260) 197 (187) 0.155

3 274 (260) 411 (390) 337 (319) 0.081

4 411 (390) 549 (520) 475 (450) 0.047

5 549 (520) 686 (650) 612 (580) 0.029

6 686 (650) 823 (780) 749 (710) 0.018

7 823 (780) 960 (910) 886 (840) 0.011

8 960 (910) 1097 (1040) 1024 (971) 0.007

9 1097 (1040) 1234 (1170) 1162 (1101) 0.005

10 1234 (1170) 1372 (1300) 1299 (1231) 0.003

11 1372 (1300) 1509 (1430) 1436 (1361) 0.002

12 1509 (1430) 1646 (1560) 1573 (1491) 0.001

13 1646 (1560) 1783 (1690) 1710 (1621) 0.001

14 1783 (1690) 1920 (1820) 1847 (1751) 0.001

15 1920 (1820) Infinity 2276 (2157) 0.001

B-11
Table 9

Discretized Distribution for Case 6 Heat Release Rate (Pumps - Electrical Fires)

Heat Release Rate - kW (Btu/s)

Bin Severity Factor (Pi)

Lower Upper Point Value

1 0 (0) 26 (25) 11 (10.5) 0.446

2 26 (25) 53 (50) 38 (36) 0.219

3 53 (50) 79 (75) 64 (61) 0.129

4 79 (75) 106 (100) 92 (87) 0.078

5 106 (100) 132 (125) 118 (112) 0.048

6 132 (125) 158 (150) 145 (137) 0.030

7 158 (150) 185 (175) 171 (162) 0.019

8 185 (175) 211 (200) 197 (187) 0.012

9 211 (200) 237 (225) 224 (212) 0.007

10 237 (225) 264 (250) 250 (237) 0.005

11 264 (250) 290 (275) 276 (262) 0.003

12 290 (275) 317 (300) 303 (287) 0.002

13 317 (300) 343 (325) 329 (312) 0.001

14 343 (325) 369 (350) 356 (337) 0.001

15 369 (350) Infinity 427 (405) 0.001

B-12
Table 10

Discretized Distribution for Case 7 Heat Release Rate (Motors)

Heat Release Rate - kW (Btu/s)

Bin Severity Factor

(P,)

Lower Upper Point Value

1 0 (0) 7 (7) 5 (4.4) 0.132

2 7 (7) 15 (14) 12 (11) 0.227

3 15 (14) 22 (21) 18 (17) 0.205

4 22 (21) 30 (28) 25 (24) 0.153

5 30 (28) 37 (35) 33 (31) 0.105

6 37 (35) 44 (42) 40 (38) 0.069

7 44 (42)ý 52 (49) 47 (45) 0.043

8 52 (49) 59 (56) 55 (52) 0.027

9 59 (56) 66 (63) 62 (59) 0.016

10 66 (63) 74 (70) 70 (66) 0.010

11 74 (70) 81 (77) 77 (73) 0.006

12 81 (77) 89 (84) 84 (80) 0.003

13 89 (84) 96 (91) 92 (87) 0.002

14 96 (91) 103 (98) 99 (94) 0.001

15 103 (98) Infinity 116 (110) 0.001

B-13
Table 11

Discretized Distribution for Case 8 Heat Release Rate (Transients1 )

Heat Release Rate - kW (Btu/s)

Bin Severity Factor

(Ps)

Lower Upper Point Value

1 0 (0) 37 (35) 22 (21.2) 0.169

2 37 (35) 74 (70) 55 (52) 0.249

3 74 (70) 111 (105) 92 (87) 0.205

4 111 (105) 148 (140) 128 (121) 0.143

5 148 (140) 185 (175) 165 (156) 0.093

6 185 (175) 222 (210) 202 (191) 0.058

7 222 (210) 258 (245) 238 (226) 0.035

8 258 (245) 295 (280) 275 (261) 0.020

9 295 (280) 332 (315) 312 (296) 0.012

10 332 (315) 369 (350) 349 (331) 0.007

11 369 (350) 406 (385) 386 (366) 0.004

12 406 (385) 443 (420) 423 (401) 0.002

13 443 (420) 480 (455) 460 (436) 0.001

14 480 (455) 517 (490) 497 (471) 0.001

15 517 (490) Infinity 578 (548) 0.001

B-14
Table 12

Damage Criteria for Electrical Cables - Generic Screening Criteria for the Assessment

of the Ignition and Damage Potential of Electrical Cables [See Ref 8-1]

Cable Type Radiant Heating Criteria Temperature Criteria

Thermoplastic 6 kW/m 2 (0.5 BTU/ft2s) 205°C (400°F)

Thermoset 11 kW/m 2 (1.0 BTU/ft2s) 330-C (625-F)

B-15
Probability of Target Damage: [SF*Pns](d)

0.0 0.5 1.0 1.5 2.0 2.5 3.0

1 .00E-01 __ _ _ _ _ _ _

___ -_ _ _-- - 0- Q ualified -

1.OOE-02 _.-- -- Unqualified

1.OOE-03 _ -_ __

1.OOE-04 _

1.OOE-05

Damage Distance [m]

Figure 1

Likelihood of Target Damage Calculated as the Severity Factor Times the Probability

of Non-suppression for MCB Fires

B-1 6
Table 13

Probability Distribution for Rate of Fires Suppressed per Unit Time, X

Number of Total 501h 95th

Suppression Curve Events in Duration X Mean 5 Per Per Per Curve

T/G fires 21 749 0.03 0.02 0.03 0.04

Control room 6 18 0.33 0.15 0.32 0.58

PWR containment 3 23 0.13 0.04 0.12 0.27

Outdoor transformers 14 373 0.04 0.02 0.04 0.06

Flammable gas 5 195 0.03 0.01 0.02 0.05

Oil fires 36 404 0.09 0.07 0.09 0.11

Cable fires 4 11 0.24 0.12 0.33 0.70

Electrical fires 112 937 0.12 0.10 0.12 0.14

Welding fires 19 99 0.19 0.13 0.19 0.27

Transient fires 24 199 0.12 0.08 0.12 0.16

High energy arcing faults 5 118 0.01 0.02 0.04 0.08

All fires 250 3260 0.08 0.07 0.08 0.08

B-1 7
Table 14

Numerical Results for Suppression Curves

(n

(n

0) E

(n) CU Cn C (

Cc u) E

2) U)

C) CU U) CU U

. -• -~- - 0 U£

C .w C: : "o.._, 0 E E o c -- LE.. .2 T _ 0 C E ( • = U• (n 0 4 - o6 ,T 0- of ..- 2 

CD 0C E 0 C:)

0 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

5 0.87 0.94 0.83 0.88 0.64 0.55 0.55 0.52 0.38 0.19 0.30 0.68

10 0.76 0.88 0.69 0.77 0.41 0.30 0.30 0.27 0.15 0.04 0.09 0.46

15 0.66 0.83 0.57 0.68 0.26 0.16 0.16 0.14 0.06 0.01 0.03 0.32

20 0.57 0.78 0.47 0.60 0.17 0.09 0.09 0.07 0.02 0.00 0.01 0.22

25 0.50 0.73 0.39 0.53 0.11 0.05 0.05 0.04 0.01 * 0.00 0.15

30 0.43 0.69 0.32 0.46 0.07 0.03 0.03 0.02 0.00 * 0.10

35 0.37 0.64, 0.27 0.41 0.04 0.01 0.01 0.01 0.00 * * 0.07

40 0.33 0.61 0.22 0.36 0.03 0.01 0.01 0.01 * * * 0.05

45 0.28 0.57 0.18 0.32 0.02 0.00 0.00 0.00 * * * 0.03

50 0.25 0.53 0.15 0.28 0.01 0.00 0.00 0.00 * * * 0.02

55 0.21 0.50 0.13 0.24 0.01 0.00 0.00 * * * * 0.01

60 0.19 0.47 0.11 0.21 0.00 * * * * * * 0.01

65 0.16 0.44 0.09 0.19 0.00 * * * * * * 0.01

70 0.14 0.42 0.07 0.17 0.00 * * * * * * 0.00

75 0.12 0.39 0.06 0.15 0.00 * * * * * * 0.00

80 0.11 0.37 0.05 0.13 * * * * * * * 0.00

85 0.09 0.34 0.04 0.11 * * * * * * * 0.00

90 0.08 0.32 0.03 0.10 * * * * * * * 0.00

95 0.07 0.30 0.03 0.09 * * * * * * * *

100 0.06 0.29 0.02 0.08 * * * * * * * *

• A value of 1 E-3 should be used

B-18
Appendix C: Exercise Set Solutions

Session 1b: Example Problems (Plant Partitioning)

C-1
Workshop Problems for Task 1: Plant Boundary Definition and Partitioning

Workshop Problem Set 01-01

Step 1 - Selection of Global Plant Analysis Boundary: Using Drawing # 01 in the Sample

Package and the information provided in other drawings, identify the Global Plant Analysis

Boundaries in terms of plant areas. Make a complete list of plant areas shown on Drawing #01

in the matrix provided below. Specify whether or not the area shall be included within the

Global Plant Analysis Boundaries and then provide the basis of your decision.

Plant Area Included? Basis

Auxiliary Building Yes Contains equipment and cables that may be included in the

fire PRA analysis

Containment Yes Contains equipment and cables that may be included in the

fire PRA analysis

Diesel Generator Building Yes Contains equipment and cables that may be included in the

fire PRA analysis

Turbine Building Yes Contains equipment and cables that may be included in the

fire PRA analysis

Yard Yes Contains equipment and cables that may be included in the

fire PRA analysis

Security Building No There are no equipment or cables in this building needed

for safe shutdown

Switchyard No Offsite power is impacted from equipment or cable failure in

the Switchyard. However, the impact of a fire event in the

switchyard would be limited to loss of offsite power and no

other safe shutdown related functions. Therefore,

cwin~fh~iprA firo r .r Inn~ rar n rar+ of lace of aifeito

Intake Structure Yes Contains equipment and cables that may be included in the

fire PRA analysis

C-2
Workshop Problem Set 01-02

Step 2: Plant Partitioning: Using the drawings provided in the Sample Package, identify the set

of fire compartments that you will consider for the fire PRA. In the following matrix (1) list

selected compartments, (2) give each an identification number, (3) identify the associated plant

area for each compartment from the Solution Statement for Problem Set 01-01. Provide

comments where warranted.

Fire Comp. Fire Compartment Plant Area Comments

ID # Descriptor

1 Main Control Room Auxiliary Building Includes the kitchen and Shift

Supervisor's Office

2 Aux Bldg El. 0 Ft Auxiliary Building

3 Cable Spreading Room Auxiliary Building

4A Aux Bldg. El. -20 Ft, Auxiliary Building

RHR Room

4B Aux Bldg. El. -20 Ft, Auxiliary Building

AFW Room

5 Battery Room A Auxiliary Building 1 hour rated walls and 2 hour rated

ceiling within the Switchgear rooms

6 Battery Room B Auxiliary Building 1 hour rated walls and 2 hour rated

ceiling within the Switchgear rooms

7 Containment Containment

8A DG-A Room Diesel Generator Building

C-3
Fire Comp. Fire Compartment Plant Area Comments

ID # Descriptor

8B DG-B Room Diesel Generator Building

9 SWG Access Room Auxiliary Building

10 Switchgear Room A Auxiliary Building

11 Switchgear Room B Auxiliary Building

12 Turbine Bldg El. 0 Ft Turbine Building

13 Yard Yard Includes the Transformers next to the

Diesel Generator Building and the two

safety related tanks.

14 Intake Structure Intake Structure A long building with some divisions

with large openings among them with

no doors isolating each compartment

from other compartments.

15 Battery Room 1 Turbine Building 1 hour rated walls and 2 hour rated

ceiling within the Switchgear rooms

16 Stairway Auxiliary Building All doors are 1 hour rated

17 Control Room Access Auxiliary Building

C-4
Workshop Example

Step 3: Compartment Information Gathering and Characterization: The following tabulation

provides an example of the information about fire compartments that may be used in a fire PRA

project.

Item Resolution

Fire Compartment ID # 9

Fire Compartment Switchgear Access Room

Building Auxiliary Building

Boundary Characteristics The compartment is bounded by 3-hr rated fire walls, ceiling and floor.

Ventilation Features The ventilation is provided by the Auxiliary Building HVAC system (1).

The equipment housed in this compartment can function properly and

perform their safe shutdown duties in case of total loss of the HVAC

system.

Fire Protection Features The fire protection features of this compartment includes:

1. Handheld extinguishers inside the compartment (2 units) (1)

2. Wet hose reel outside the door inside the stairwell(1 )

3. Smoke detectors attached to the ceiling (6 units)(1)

4. Automatic CO2 system

Fire Sources The following ignition sources were identified in this compartment.

1. MCC-A

2. MCC-B

3.125VAC-A

4.125VAC-B

5. ATS

6. Lighting Fixtures (10 units)(1)

Additionally the following combustibles are present:

1. Cable trays containing thermoset control cables

2. Wooden desk used by the electrical department(1 )

Adjacent Compartments The following compartments share a wall, ceiling or floor with this

compartment:

1. Switchgear Room A

2. Switchgear Room B

3. Stairwell

4. Charging pump room

5. Cable spreading room

Access Routes 1. This room can be accessed from outside through the stairwell

2. Switchgear Rooms A and B are accessed through this room

Components /Systems / See the component and cable lists provided in Tasks 2 and 3.

Cables Present

SSD Human Actions To be completed after Task 12 is completed.

Credited in this

Compartment

(1) Provided here to demonstrate how this part of the step may be addressed. These features are not intended to be

included in the Fire PRA of this Sample Package.

C-5
Session 2b: Example Problems (Fire Ignition Frequency)

C-6
Workshop Problems for Task 6: Fire Ignition Frequency

Workshop Problem Set 06-01

Step 1: Mapping plant ignition sources to generic sources: Using the information provided in

this Sample Package, map the items listed in the following table to generic sources.

Ecription EEquipment Bi # Bin Description

ID Type Comment\

HPI-B High pressure safety injection pump B Pump 21 Pumps

MOV-1 HPI valve MOV 14 Electric Motors

MOV-5 RWST isolation valve MOV -- Less than 5hp motor

BAT-B Train B Battery Battery 1 Batteries

RCP-1 Reactor coolant pump 1 Pump 2 Reactor Coolant Pump

AOV-1 / Assumed as insignificant

(SOV-1) Pressure operated relief valve AOV -- ignition source.

PT-1 RCS pressure Instrument -- Assumed as insignificant

ignition source.

EDG-A Train A Emergency Diesel Generator Diesel Generator 8 Diesel Generators

MCC-B1 Train B 480 V Motor Control Center Motor Control 15 Electrical Cabinets

Center

ATS-1 Automatic Transfer Switch ATS 15 Electrical Cabinets

VITAL-A Train A 120 VAC Vital Bus 120VAC Bus 15 Electrical Cabinets

SWGR-A Train A 4160 V Bus Switchgear 15/16 ElectdcalCabinets/HEAF

LC-A Train A 480 V Load Center Load Center 15/16 Electrical Cabinets/HEAF

SST-A Train A Station Service Transformer Transformer 23a Transformers (Dry)

BC-A Train A Battery Charger Battery Charger 10 Battery Chargers

DC BUS-A Train A 125 VDC Bus DC Bus 15 Electrical Cabinets

PNL-A Train A 125 VDC Panel Panelboard 15 Electrical Cabinets

INV-A Train A Inverter Inverter 15 Electrical Cabinets

AFW-A Motor driven AFW pump A Pump 21 Pumps

AFW-B Steam driven AFW Pump B Pump 21 Pumps

SUT-1 Startup Transformer Transformer 29 Yard transformers (Others)

The following table provides the components specifically addressed in the Fire PRA of this Sample

Package.

C-7
EupetEquipment BinDecito Equipment Equipment Description Type Bin # Description

ID Type Comment\

TI-1 Letdown heat exchanger outlet temp Instrument -- Comment 1 (below)

HPI-A High pressure safety injection pump A Pump 21 Pumps

HPI-B High pressure safety injection pump B Pump 21 Pumps AOV-2 /

(SOV-2),I SOV-2 Letdown isolation valve AOV -- Comment 1

AOV-3 / Charging pump injection valve AOV -- Comment 1

MOV-1 HPI valve MOV 14 Electric Motors

MOV-2 VCT isolation valve MOV 14 Electric Motors

MOV-5 RWST isolation valve MOV -- Less than 5hp motor

MOV-6 RWST isolation valve MOV -- Less than 5hp motor

MOV-9 HPI valve MOV 14 Electric Motors

RHR-B RHR pump B Pump 21 Pumps

MOV-3 Cont. sump recirc valve MOV 14 Electric Motors

MOV-4 Cont. sump recirc valve MOV 14 Electric Motors

MOV-8 RHR outboard suction valve MOV 14 Electric Motors

BAT-A Train A Battery Battery 1 Batteries

BAT-B Train B Battery Battery 1 Batteries

RCP-1 Reactor coolant pump 1 Pump 2 Reactor Coolant Pump

AOV-1 /

(SOV-1)II SOy-i Pressure operated relief valve AOV -- Comment 1

MOV-7 RHR inboard suction valve MOV 14 Electric Motors

MOV-1 3 PORV block valve MOV -- Comment 2

LI-3 Containment sump level Instrument -- Comment 1

LI-4 Containment sump level Instrument -- Comment 1

PT-1 RCS pressure Instrument -- Comment 1

EDG-A Train A Emergency Diesel Generator Diesel 8 Diesel Generators Generator ___

EDG-B Train B Emergency Diesel Generator Diesel 8 Diesel Generators Generator 8 DislGnrts

ANN-1 AFW motor high temp Annunciator -- Comment 1

MCC-A1 Train A 480 V Motor Control Center Motor Control 15 Electrical Cabinets Center

MCC-B1 Train B 480 V Motor Control Center Motor Control 15 Electrical Cabinets

Center

ATS-1 Automatic Transfer Switch ATS 15 Electrical Cabinets

VITAL-A Train A 120 VAC Vital Bus 120VAC Bus 15 Electrical Cabinets

VITAL-B Train B 120 VAC Vital Bus 120VAC Bus 15 Electrical Cabinets

SWGR-A Train A 4160 V Bus Switchgear 15/16 Electrical Cabinets/HEAF

LC-A Train A 480 V Load Center Load Center 15/16 Electrical Cabinets/HEAF

SST-A Train A Station Service Transformer Transformer 23a Transformers (Dry)

BC-A Train A Battery Charger Battery Charger 10 Battery Chargers

DC BUS-A Train A 125 VDC Bus DC Bus 15 Electrical Cabinets

PNL-A Train A 125 VDC Panel Panelboard 15 Electrical Cabinets

INV-A Train A Inverter Inverter 15 Electrical Cabinets

SWGR-B Train B 4160 V Bus Switchgear 15/16 Electrical Cabinets/HEAF

LC-B Train B 480 V Load Center Load Center 15/16 Electrical Cabinets/HEAF

SST-B Train B Station Service Transformer Transformer 23a Transformers (Dry)

C-8
The following table provides the components specifically addressed in the Fire PRA of this Sample

Package.

Equipment Equipment Description Equipment Bin # Bin Description /

ID Type Comment\

BC-B Train B Battery Charger Battery Charger 10 Battery Chargers

DC BUS-B Train B 125 VDC Bus DC Bus 15 Electrical Cabinets

PNL-B Train B 125 VDC Panel Panelboard 15 Electrical Cabinets

INV-B Train B Inverter Inverter 15 Electrical Cabinets

LC-1 Non-Safety 480 V Load Center Load Center 15/16 Electrical Cabinets/HEAF

LC-2 Non-Safety 480 V Load Center Load Center 15/16 Electrical Cabinets/HEAF

SWGR-1 Non-Safety 4160 V Bus Switchgear 15/16 Electrical Cabinets/HEAF

SWGR-2 Non-Safety 4160 V Bus Switchgear 15/16 Electrical Cabinets/HEAF

COMP-1 Instrument air compressor Compressor 9 Air Compressors

MOV-10 AFW discharge valve MOV -- Comment 2

MOV-1 1 AFW discharge valve MOV -- Comment 2

MOV-18 AFW C.Pump Discharge MOV -- Comment 2

SST-1 Non-Safety Station Service Transformer Transformer 23b Transformers (Oil filled)

SST-2 Non-Safety Station Service Transformer Transformer 23b Transformers (Oil filled)

MCC-i Non-Safety 480 V Motor Control Center Motor Control 15 Electrical Cabinets Center Contro

MCC-2 Non-Safety 480 V Motor Control Center Motor Control 15 Electrical Cabinets

________ ____________________________ Center _____________

BC-1 Non-Safety Swing Battery Charger Battery Charger 10 Battery Chargers

BAT-1 Non-Safety Battery Battery 1 Batteries

DC BUS-1 Non-Safety 250 VDC Bus DC Bus 15 Electrical Cabinets

AFW-A Motor driven AFW pump A Pump .21 *Pumps

AFW-B Steam driven AFW Pump B Pump 21 Pumps

AFW-C AFW pump C Pump 21 Pumps

MOV-14 AFW turbine steam line isolation valve MOV -- Comment 2

MOV-15 AFW steam inlet throttle valve MOV -- Comment 2

MOV-16 AFW test line isolation valve MOV -- Comment 2

MOV-17 AFW test line isolation valve MOV -- Comment 2

MOV-19 AFW test line isolation valve MOV -- Comment 2

V-12 CST isolation valve MOV -- Comment 2

LI-i RWST level Instrument -- Comment 1

LI-2 RWST level Instrument -- Comment 1

SUT-1 Startup Transformer Transformer 27/28 Yard transformers (Others)

Comment 1: Assumed as insignificant ignition source.

Comment 2: Less than 5hp motor

C-9
Workshop Problem Set 06-04

Step 4: Mapping Plant-Specific Locations to Generic Locations: Using the information

provided in this Sample Package, map the items listed in the following table to the applicable

generic locations provided in NUREG/CR 6850. Note that some of the compartments may map

to more than one Generic Location.

Step 5: Location Weighting Factors: Assign the location weighting factors of the Fire

Compartments in the following table.

Fire

Comp. Comp # Plant Fire Compartment Plant Area Generic Location WL

1 Main Control Room Auxiliary Building See Note 1 1.0

2 Aux Bldg El. 0 Ft Auxiliary Building See Note 2 1.0

3 Cable Spreading Room Auxiliary Building See Note 2 1.0

4A RHR Pump Room Auxiliary Building See Note 2 1.0

41B AFW Pump Room Auxiliary Building See Note 2 1.0

5 Battery Room A Auxiliary Building See Note 3 1.0

6 Battery Room B Auxiliary Building See Note 3 1.0

9 SWG Access Room Auxiliary Building See Note 2 1.0

10 Switchgear Room A Auxiliary Building See Note 2 1.0

11 Switchgear Room B Auxiliary Building See Note 2 1.0

14 Stairway Auxiliary Building See Note 2 1.0

7 Containment Containment Containment 1.0

8A DG-A Room DG Bldg. See Note 4 1.0

8B DG-B Room DG Bldg. See Note 4 1.0

12 Turbine Bldg El. 0 Ft Turbine Building See Note 5 1.0

15 Battery Room 1 Turbine Building See Note 6 1.0

13 Yard Yard See Note 7 1.0

14 Intake Structure Intake Structure Plant-Wide Components 1.0

Note 1: Control Room (for the Main Control Board) and Control/Aux/Reactor Building (for cable and transient fires)

Note 2: Control/Aux/Reactor Building (for cable and transient fires) and Plant-Wide Components for all other items

Note 3: Battery Room (for the batteries) and Control/Aux/Reactor Building (for cable and transient fires)

Note 4: Diesel Generator Room (for the Diesel Generators), Control/Aux/Reactor Building (for cable and transient

fires), and Plant-Wide Components for all other items

Note 5: Turbine and Plant-Wide Components (for all items not specifically assigned to the Turbine Building)

Note 6: Battery Room (for the batteries) and Turbine Building (for cable and transient fires)

Note 7: Transformer Yard and Plant-Wide Components for all other items

C-10
Workshop Problem Set 06-05

Step 5: Location Weighting Factors: At a two-unit nuclear power plant, the Main Control Room

is shared between the two units. The control room consists of two separate Main Control Boards

that do not share any controls and are dedicated to one unit each. There are 5 electrical cabinets

in the control room in addition to the Main Control Boards that are shared between the two units.

a. For Unit 1, establish the Location Weighting Factor of the Main Control Board

WL, MCR, Main Control Board ý 2.0

b. For Unit 1, establish the Location Weighting Factor of the electrical cabinets.

WL, MCR, Electrical Cabinets = 2.0

c. For Unit 1, establish the Location Weighting Factor of transient fires in the Main Control Room

WL, MCR, Transients = 2.0

C-11
Workshop Problem Set 06-06

Step 6: Fixed Fire Ignition Source Counts: Estimate the ignition source counts for only those

items that are noted under each picture and are visible in the foreground of the picture:

Electrical Panels: 8 vertical sections Electrical Panels: 7 vertical sections

Transformers: I

Transformers: I Electrical Panels: 5 vertical sections

Transformers: 2

Electrical Panels: 2 vertical sections Electrical Panels: 3 vertical sections

C-12
Electrical Panels: 2 vertical sections ElectricalPanels: Ivertical sections

Electrical Panels: No count -Sealed with low

volta~qe circuits

C-13
Workshop Problem Set 06-07

Step 6: Fixed Fire Ignition Source Counts: Estimate the ignition source counts for the components identified in Step 1 above.

Bin # and Description (per Table 6-1)

1 2 8 4 9 1 10 114 1 15 16 21 23at23b 29

U)

0

0

Cu

0 .

0oE

0 6(

U) 0

4)

6

C•

0-

09

-0

._)

0

0

0

0Q

UO

U) U/)

.)

0.

E

0

U,

U)

0

0)

Cu

C.)

0

Cu

0

U

U) 0

CD

UCu

0

Fw

0)-

aLL

u"

._)

0.

E

0.

0

UE

U)

t4 -

U)

E)

0

CU) 4

*0

XFMR- XFMR- XFMR-

# Compartment Plant Area BAT RCP DG MCB AC BC EM EC HEAF PMP XFMR il Yrd Dry Oil Yard

1 Main Control Room Control/Aux/Reactor Building 0 0 0 1 0 0 0 1 0 0 0 0 0

2 Aux Bldg El. 0 Ft Control/Aux/Reactor Building 0 0 0 0 0 0 3 0 0 2 0 0 0

3 Cable Spreading Room Control/Aux/Reactor Building 0 0 0 0 0 0 0 0 0 0 0 0 0

4A RHR Pump Room Control/Aux/Reactor Building 0 0 0 0 0 0 3 0 0 1 0 0 0

4B AFW Pump Room Control/Aux/Reactor Building 0 0 0 0 0 0 0 0 0 2 0 0 0

5 Battery Room A Plant Wide Components 1 0 0 0 0 0 0 0 0 0 0 0 0

6 Battery Room B Plant Wide Components 1 0 0 0 0 0 0 0 0 0 0 0 0

9 SWG Access Room Plant Wide Components 0 0 0 0 0 0 0 31 0 .0 0 0 0

10 Switchgear Room A Plant Wide Components 0 0 0 0 0 1 0 25 14 0 1 0 0

11 Switchgear Room B PlantWide Components 0 0 0 0 0 1 0 24 14 0 1 0 0

14 Stairway Plant Wide Components 0 0 0 0 0. 0 0 0 0 0 0 0 0

7 Containment Containment 0 1 0 0 0 0 1 0 0 0 0 0 0

8A DG-A Room Plant Wide Components 0 0 1 0 0 0 0 0 0 0 0 0 0

8B DG-B Room Plant Wide Components 0 0 1 0 0 0 0 0 0 0 0 0 0

12 Turbine Bldg El. 0 Ft Plant Wide.Components 0 0 0 2 1 0 57 28 1 0 2 0

15 Battery Room 1 Plant Wide Components 1 0 0 0 0 0 0 0 0 0 0 0 0

13 Yard Plant Wide Components 0 0 0 0 0 0 0 0 0 0 0 0 3

14 Intake Structure Plant Wide Components 0 0 0 0 0 0 0 0 0 0 0 0 0

Total 3 0 2 1 2 3 7 136 56 6 2 2 3

C-14
Workshop Problem Set 06-08

Step 7: Ignition Source Weighting Factors: For an NPP, the fire PRA analysts have counted 23

pumps within the Plant Analysis Boundary.

* For RHR Pump RHRP-C located in RHR Pump room (FZ-03A), which in turn is located

in the Reactor Building, establish the IS, J and L subscripts of:

WIS,J,L = W RHRP-C,FZ-03A,AUX BLDG

" For the same RHR Pump, RHRP-C, calculate the Ignition Source Weighting Factor

W = 1/23 = 0.043

" RHR Pump room FZ-03A contains three pumps. Calculate the ignition source weighting

factor for the pumps in this compartment.

W= 3/23=0.13

C-15
Workshop Problem Set 06-09

Step 7: Ignition Source Weighting Factors: For an NPP, the fire PRA analysts have counted

351 electrical cabinet vertical sections within the Plant Analysis Boundary.

" 480VAC MCC-A is composed of 32 breakers arranged in 8 vertical segments. Calculate

the ignition source weighting factor for this MCC.

WMCCA = 8/351 = 0.023

* 4kV non- 1E Switchgear 1 is composed of 8 breakers. Each breaker takes up one vertical

segment of the switchgear. Calculate the ignition source weighting factor for this

electrical panel.

WSWG-1 = 8/351 = 0.023

" The local control panel, CP-1, for the chemicals addition system located in the Reactor

Building has the following dimensions: 2' Deep, 12'Long, 8'High. There are no

partitions within the panel. Calculate the ignition source weighting factor for this

electrical panel.

Wcp-l = 1/351 = 0.0028

C-16
Workshop Problem Set 06-10

Step 7: Ignition Source Weighting Factors: Using the information provided in the solution for Problem Set 06-07, calculate the

component weighting factors for the components listed below.

Bin # and Description (per Table 6-1)

1 2 1 8 1 4 1 9 110 114 15 116 121 123a 23b 129

W

4) 0 W L)

0.

E

03

U)

-o

03

00

I

0

U)

E

0

C.,

~U) 

.CDC.) LU- LU-0

0)Mt

, r Cj 75

0

E

Cn

0)

0'~-

CU)

(V

I0

Co0

U)

0-

XFMR- XFMR- XFMR-

# Compartment Plant Area BAT RCP DG MCB AC BC EM EC HEAF PMP Dr Oil Yard

1 Main Control Room .ontrol/Aux/Reactor Building 1.OE+00 _ 4E-03

2 Aux Bldg El. 0 Ft .ontrol/Aux/Reactor Building _.3E-01 3.3E-01

3 Cable Spreading Room ontrol/Aux/Reactor Building

4A RHR Pump Room .ontrol/Aux/Reactor Building _.3E-01 1.7E-01

4B AFW Pump Room 3ontrol/Aux/Reactor Building 3.3E-01

5 Battery Room A ýlant Wide Components .3E-01

6 Battery Room B •lant Wide Components 3.3E-01

9 SWG Access Room •lant Wide Components 2.2E-01

10 Switchgear Room A •lant Wide Components _3E-01 1.8E-01 2.5E-01 5.0E-01

11 Switchgear Room B •lant Wide Components 3.3E-011 1.8E-01 .5E-01 5.0E-01

14 Stairway •lant Wide Components

7 Containment Zontainment 1.OE+00 1.4E-01

8A DG-A Room •lant Wide Components _5.OE-01

8B DG-B Room •lant Wide Components 5.0E-01

12 Turbine Bldg El. 0 Ft :'ant Wide Components .3E-01 1.OE+00 .3E-01 _ .2E-01 0E-01 1.7E-01 1.OE+00

15 Battery Room 1 •lant Wide Components

13 Yard rlant Wide Components 1.0E+00

14 Intake Structure ýIant Wide Components

C-17
Workshop Problem Set 06-11

Transient Ignition Source Weighting Factors: An NPP is composed of three compartments

with the following characteristics:

A. Enter the influencing factors for each compartment and category:

Influencing Factor Cable Run (selfignited cable

Compartment Maintenance Occupancy Storage fires)

Compartment 1 10 1 10 1,000

Compartment 2 3 1 3 --

Compartment 3 1 10 10 10,000

Total 14 12 23 11,000

B. Calculate the ignition source weighting factors for each compartment

Transients fires Cable fires Cable Run (selfCompartment General caused by caused by Cabie cable Transients welding and welding and ignited cable

cutting cutting fires)

Compartment 1 43% 10/14 50% 9.1%

Compartment 2 14% 3/14 -- --

Compartment 3 43% 1/14 50% 90.9%

Total 100.0% 100.0% 100.0% 100.0%

C. Calculate the ignition frequencies for each compartment

Transients fires Cable fires Cable Run (selfGeneral caused by caused by ignited cable

Transients welding and welding and igeda

cutting cutting fires)

Total Location

Frequen Frequency (/ry) 3.90E-03 9. 70E-03 1.60E-03 4.40E-03

Compartment 1 1.67E-03 6.93E-03 8.OE-04 4.OOE-04

Compartment 2 5.57E-04 2.08E-03 ....

Compartment 3 1.67E-03 6.93E-04 8.OE-04 4.OOE-03

C-18
Session 6b: Example Problems (Scoping Fire Modeling)

C-19
Workshop Problems on Task 8: Scoping Fire Modeling

This handout includes workshop problems on the different steps of Task 8: Scoping Fire

Modeling. Problems are grouped by steps.

Step 1: Preparation for Walkdown

Step 1 has three sub-steps: 1) Estimate heat release rate for fixed ignition source screening, 2)

Target and intervening combustibles damage or ignition criteria, and 3) Develop a zone of

influence.

Workshop problem 08-01:

Step 1.1: Estimate heat release rate for fixed ignition source screening: Assign a heat

release rate to the ignition sources depicted in the pictures of the following Table 08-01. For

this exercise, assume that the plant has a mix of qualified and unqualified cables. The heat

release rates are listed in Table E-1 of NUREG/CR-6850.

Table 08-01: Inputs for Workshop problems 1

9th Pretl

Ignition Source Table E-1 Case 98 HPercentile Justification HRR

Table 8-1 in

NUREG/CR-6850

suggests the use of

7 69 kW the "Electric Motors"

heat release rate

probability distribution

for dry transformers

Dry transformer

Fire protection panels

have usually moderate

to high combustible

loading (including

relays circuit cards

464 kW etc.). It is therefore

assumed that the fire

may be able to

propagate to more

than one cable

Fire protection panel bundle.

Table 8-1 in

NUREG/CR-6850

suggests the use of

the "Electric Motors"

7 69 kW heat release rate

probability distribution

for ventilation subsystems

Ventilation sub-system

fc Table 8-1 in 6 21 NUREG/CR-6850

C-20
9th Pretl

Ignition Source Table E-1 Case 98h Percentile Justification HRR

suggests not to screen

pumps due to the

need of evaluating oil

fires. Table E-1

suggests a heat

release rate of 211 kW

for electrical fires only.

Pum s

C-21
Workshop Problem Set 08-02:

Step 1.2: Target and intervening combustible damage and ignition criteria: Assign

damage criteria to the ignition sources depicted in Table 08-01. For this exercise, assume that

the plant has a mix of thermoset and thermoplastic cable. Generic damage criteria are listed in

Table H-1 of NUREG/CR-6850.

Table 08-02: Inputs for workshop problem 2

Target/Intervening Damage Criteria Justification

Combustible

From Table H-1 in NUREG/CR6850. Page H-2 of

NUREG/CR-6850 suggests

6 kW/m2 (0. 5 B TU/ft2s) or using the "weakest link" for

Cablesin a ladder back tray 205°C (400°F) determining damage criteria.

Therefore the damage criteria

for thermoplastic cable were

selected.

Page H-2 of NUREG/CR-6850

suggests using the "weakest

link" for determining damage

6 kW/m2 (0.5 BTU/ft2s) or criteria. Therefore the damage

Cables in a solid tray 205oc (400OF) criteria for thermoplastic cable

were selected. Solid trays are

treated as conduits in this task.

See second bullet in page H-I

of NUREG/CR-6850.

From Table H-I in NUREG/CR- Theromset cable in a conduit kW/m2 (1.0 BTU/ft2s) or 6850. See second bullet in

page H-1 of NUREG/CR-6850.

See section H.2 in NUREG/CR6 kW/m2 (0.5 BTU/ft2s) or 6850. Cables connecting the Motor operated valve (MOV). 205-C (400°F) MOV are assumed

thermoplastic in this example.

Cabinet with a solid state evice 3 kW/m2 (0.25 BTU/ft2s) or See section H.2 in NUREG/CR65°C (150°F) 6850.

C-22
Workshop Problem Set 08-03

Step 1.3: Develop zone of influence: Calculate the heat release rate required for generating

target damage for the following ignition source/target combination and determine if the ignition

source can be screened. Use the engineering calculations described in NUREG-1 805 for

determining the heat release rate value.

Target in the hot gas layer:

M A cable tray target is located near the ceiling in a room approximately 21' by 7' and has

a normally closed door on each end. The room is approximately 20' high. The inside

walls of the MCC room are reinforced concrete. There is one MCC cabinet in the room.

The MCC cabinet has unqualified cable.

The MQH room temperature correlation described in Section 2.6 of NUREG- 1805 was selected

for calculating the hot gas layer temperature in the room. Input values for the MQH model are

listed in Table 08-03. Notice that a heat release rate of 600 kW generates room temperatures

of approximately 205 °C. This calculation assumes a 20-min fire duration and one open door in

the room.

Table 08-03: MQH room temperature correlation analysis

MCC Room

Length [ft]: 21

Width [ft]: 7

Height [ft]: 20

MQH Temperature Correlation

Inputs

Ambient temperature [C] 20

Duration [sec] 1200

Opening area [m2] 2

Height of opening [m] 2

Room length Em) 6

Room width [m] 2

Room height [m] 6

Thermal conductivity [kW/mK] 0.0014

Density [kg/m3] 2000

Specific heat [kJ/kg] 0.88

Wall thickness [m] 0.6

HRR [kW] 600

Results

Room Temp [C] 205

C-23
* Target subjected to flame impingement or fire plume temperatures:

R A vertical cable tray is located 5' ft from a floor based ventilation subsystem.

The Heskestad' flame height and plume temperature correlations described in Chapter 3 and 9

of NUREG-1805 respectively were selected for calculating flame height and room temperature.

Input values for the models are listed in Table 08-04 and Table 08-05. Notice that a heat

release rate of 250 kW generates a flame height of 5'. In the case of the plume temperature

correlation, a heat release rate of 165 kW generates damage temperatures of approximately

205 'C at the location of the target.

Table 08-04: Heskestad flame height correlation

Heskdestad's Flame Height Correlation

Inputs

Fire diameter [m] 0.6

HRR [kW] 250

Results [m] [ft]

Flame height [m] 1.5 5.0

Table 08-05: Heskestad plume temperature correlation

Heskestad Plume Temperature Correlation

InDuts

Ambient temperature [C] 20

Fire location factor 1

HRR [kW] 165

Fire elevation [m] 0

Target Elevation [m] 1.5

Radiation Fraction 0.40

Fire Diameter [ml I

Results

Plume Temp [C] 202

C-24
* Target subjected to flame radiation:

A conduit is located 3 ft from a battery charger with qualified cable.

The point source flame radiation model described in section 5.3 of NUREG-1805 was selected

for calculating the incident heat flux at the location of the target. Input values for the point

source model are listed in

Table 08-06. Notice that a heat release rate of 160 kW generates incident heat fluxes of 5

kW/m2.

Table 08-06: Point source flame radiation model

Point Source Flame Radiation Model

Inputs

Fire heat release rate [k&M 160

Radiation fraction 0.40

Distance from flames [m] I

Results

Heat flux [kW/m2] 5.1

C-25
Workshop Problem Set 08-04

Step 2: Plant Walkdown: Inspect the ignition source and target combination in the pictures

included in Table 08-07 and determine the appropriate zone of influence calculation necessary.

Table 08-07: Inputs for Workshop problems I

Ignition Source Ignition Zone of Influence Distance

Igniton SurceSource/Target

Targets in the conduits will

be affected by flame or

plume conditions.

Fire protection Depending on the fire size -4'

panel/Conduits above and the characteristics of

the room, the target may

also be affected by hot gas

layer temperatures.

Targets in the conduits will

be affected by flame or

plume conditions.

Electrical Depending on the fire size

cabinets/Conduit and the characteristics of

the room, the target may

also be affected by hot gas

layer temperatures.

Adjacent ventilation

subsystem will be affected

Ventilation by flame radiation.

Subsystem/Ventilation Depending on the fire size 2'

and the characteristics of the room, the target may

also be affected by hot gas

layer temperatures.

C-26
Ignition

Ignition Source SourceIarget Zone of Influence

Ventilation

Subsystem/MOV's

MOV's and associated

cables will be affected by

flame radiation from a fire in

the ventilation subsystem.

Depending on the fire size

and the characteristics of

the room, the target may

also be affected by hot gas

layer temperatures.

1-

Electrical

cabinet/Cable tray

Targets in the cable tray will

be affected by flame or

plume conditions.

Depending on the fire size

and the characteristics of

the room, the target may

also be affected by hot gas

layer temperatures.

Transformer/Cable

tray

Targets in the cable tray will

be affected by flame or

plume conditions.

Depending on the fire size

and the characteristics of

the room, the target may

also be affected by hot gas

layer temperatures.

Adjacent pump will be

affected by flame radiation.

Depending on the fire size

Pump/Pump and the characteristics of

the room, the target may

also be affected by hot gas

layer temperatures.

C-27
Step 3: Verification of Screened Ignition Sources

No workshop problem for Step 3.

Workshop Problem Set 08-05

Step 4: Calculation of Severity Factors: Calculate the severity factors for the ignition source

and target combinations listed in Workshop Problem 08-03. Use the results of Workshop

Problem Set 08-03 as inputs to this exercise.

Target in the hot gas layer

" Ignition source: MCC cabinet with unqualified cable

" Heat release rate probability distribution: Case 4, Gamma distribution with

a= 2.6 &/#= 67.8.

" Critical heat release rate: 600 kW

" Severity factor: Using a Microsoft Excel function,

SF = 1-GAMMADIST(600,2.6,67.8, TRUE) - 0.004

" Target subjected to flame impingement or plume temperatures

" Ignition source: Ventilation subsystem

" Heat release rate probability distribution: Case 7, Gamma distribution with

a =2.0= 11.7.

" Critical heat release rate: 250 kW or 165 kW

" Severity factor: Using a Microsoft Excel function,

SF = 1-GAMMADIS T(250,2,11.7, TRUE) 1.2E-8 or

SF =1-GAMMADIST(165,2,11.7, TRUE) 1. 1E-5

" Target subjected to flame radiation

" Ignition source: Battery charger with qualified cable

" Heat release rate probability distribution: Case 2, Gamma distribution with

a =0.7 & #3= 216.

" Critical heat release rate: 160 kW

" Severity factor: Using a Microsoft Excel function,

SF =1-GAMMADIST(160, 0.7,216, TRUE) - 0.83

It should be noted that this problem can also be solved using the discretized Gamma distribution tables in Appendix

E of NUREG/CR-6850. Consider the target subjected toflame radiation, which was assigned the following Case 2

gamma distribution for heat release rate:

C-28
Heat R.Is*m Rat. - k~w (haue) gin NO oe A w(W)Swvty Fgrtor

Lowr Upper Point Vake

1 0(0) 90(85) 34 (32.7) o.o

2 90(86) 179(170) 130 (12. 0.202

3 179(170) 20(266) 2 (2o2 ) 0.113

4 200(256) 359(340) 310(294) 0.067

5 3W (340) 448(425) 400(379) o.oM1

6 448(425) 836(510) 490(464) 0.028

7 588(510) we8(5"5 579(549) 0.016

8 GW(595) 717 (8"0 09(834) 0.010

9 717(600) 807(705) 759(715) 0.008

10 ,7.(766) 897 (S" 8' (a0m) 0.004

11 807 (06) 0 o(935) O6 (089) 0.003

12 08(936) 1076(1020) 102B(74) 0.002

13 1076(102D) 1168(1105) 1110(1000) 0.001

14 1166(1105) 1255(1190) 1208(1145) 0.001

15 12"5(1190) Infinity 1462 (13) 0.001

Figure 1: Table E-3 from NUREG/CR-6850

The severity factor is the sum of the severity factor column after the "Point Value"

160 kW (highlighted values in Figure 1).

C-29
Workshop Problem Set 08-06

Step 5: Calculation of Revised Compartment Fire Frequency. Determine a revised compartment ignition frequency for

switchgear room A assuming the walkdown results listed in Table 08-08.

Table 08-08: Summary of Task 8 calculations

Equipment Measured Table E- Critical HRR Room Room Calculated Room Severity Count

Description Count Fire Condition Distance I Case (Table E-1) Area (ft2) Height (ft) HRR (kW) Temp (F) Screened Factor Task 8 (ft)TrainA_60_VDoNo TrainA4160V 8 flame or plume 1.7 9Do Not 1350 20 7 N/A No 1.00 8.00

Bus Screen

Train A 480 V 6 flame radiation 4,9 Do Not 1350 20 401 N/A No 1.00 6.00

Load Center Screen

Train A Station Do Not

Service 1 flame radiation 4.5 9 Not 1350 20 336 N/A No 1.00 1.00

Transformer

Train A Battery 1 flame or plume 2.9 4 464 1350 20 25 264 No 0.98 0.98

Charger _________________

TrainA125VDC 8 flame or plume 0.7 4 464 1350 20 1 264 No 1.00 8.00

Bus

Train A 125 VDC 1 flame radiation 2.8 4 464 1350 20 129 264 No 0.60 0.60

Panel

Train A Inverter 1 flame radiation 2.0 4 464 1350 20 64 264 No 0.88 0.88

Table 08-09: Comparison of switchgear room A ignition frequency

Task 6 I Switchgear Room A = 1.5E-02

Task 8 Switchgear Room A 1.5E-02

C-30
Session lOb: Example Problems (Detailed Fire Modeling)

C-31
WORKSHOP PROBLEMS ON TASK 11A: DETAILED

FIRE MODELING

This handout includes workshop problems on the different steps of Task 11: Detailed Fire

Modeling. Problems are grouped according to the steps defined in NUREG/CR-6850. Detailed

fire modeling will be conducted in the switchgear access room (Room 9) located in elevation 20

ft of the auxiliary building.

Workshop Problem Set 11a-01

Step 1a: Identify and Characterize Compartments: Review the following information

necessary for fire modeling purposes.

- Room size: For the purpose of this exercise, assume the size of the room is 45' by 22'

by 20' high.

- Wall boundaries: The surfaces, floor, ceiling, and walls are reinforced concrete. All the

surfaces are 2' thick.

- Doors: The room has three doorways: 1) a double door connecting to switchgear room

A, 2) a double door connecting to switchgear room B, and 3) a single door connecting to

the stairwell. The size of a single door is 6.5' by 3'.

- Mechanical Ventilation: The switchgear access room has a mechanical ventilation

system with a balance 5 air changes per hour.

C-32
Workshop Problem Set 11a-02

Step 2a: Identify and Characterize fire Detection and Suppression Features and

Systems: Review the following information necessary for fire modeling purposes.

- Prompt detection: Prompt detection is not credited since there is no incipient fire

detection system in the room and no continuous fire watch.

- Prompt suppression: Prompt suppression is not credited since there is no continuous

fire watch in the room.

- Fixed fire detection system/s (type, and sensor location): An automatic fire detection

system is credited since the room is equipped with an automatic fire detection system.

The location of the relevant detectors is specified in the corresponding scenario

descriptions later in this document.

- Fixed fire suppression system/s (type and nozzle location): An automatic 002 system is

credited since the room is equipped with an automatic C02 system. Upon smoke

detection alarm, a timer starts providing 60 seconds delay for life safety purposes. The

002 is released after the delay time. The soak time is approximately 20 min.

- Fire brigade arrival time: The fire brigade arrival time is assumed to be 15 min.

- Delayed detection: Delayed detection is credited and assumed to be 15 minutes

(consistent with the example in page P-1 4 of NUREG/CR-6850).

C-33
Workshop Problem Set 11a-03

Step 3a: Characterize Fire Ignition Sources: From the Task 6 (Fire Ignition Frequencies)

calculation package, list the fixed ignition sources located in the switchgear access room (room

9) and assign a heat release rate probability distribution to each of them from Table G-1 of

NUREG/CR-6850.

Solution: Table 10 lists the recommended answer to workshop problem 3.

Table 10: Summary of ignition source characteristics in the switchgear access room.

Case (Table EI of HRR Profile (Page G-6 in NUREG/CR- Equipment ID Equipment Description NUREG/CR- 6850)

6850)

t

2 grow to a peak of 211 kW in 12 min

MCC-A1 Train A 480 V Motor Control Center Case 3 followed by steady burning for 8

additional minutes

t

2 grow to a peak of 211 kW in 12 min

MCC-B1 Train B 480 V Motor Control Center Case 3 followed by steady burning for 8

additional minutes

t

2 grow to a peak of 211 kW in 12 min

VITAL-A Train A 120 VAC Vital Bus Case 3 followed by steady burning for 8

additional minutes

t

2 growto a peakof211 kWin 12 min

VITAL-B Train B 120 VAC Vital Bus Case 3 followed by steady burning for 8

additional minutes

t

2 grow to a peak of 317 kW in 12 min

Transients Regular solid transient ignition sources. Case 8 followed by steady burning for 8

additional minutes

C-34
Step 4a: Identify Secondary Combustibles: No workshop problem is associated with this

step. The following discussion provides an example of how to identify and characterize

secondary combustibles.

Sample Analysis for Step 4a:

For the purpose of this example, let's assume that there is one cable tray stack above each

cabinet in the room. Each stack has two trays. The first tray is 1' above each cabinet. The

second tray in the stack is 1.5' above the first tray. The trays are ladder-back. A pictorial

representation of the secondary combustibles in provided in Figure 2.

Secondary

combustibles

Secondary

combustibles

Front view

Figure 2: Pictorial representation of the secondary combustibles. Drawing not to

scale.

From Table 10, the cabinets in the switchgear access room will have a peak heat release rate of

211 kW. Heskestad's flame height correlation (Chapter 3 of NUREG 1805) suggests a flame

height of approximately 4.6' above the ignition source. Therefore, the cable tray stack above

the cabinet is expected to ignite and contributing to the fire intensity. Table 11 lists the

Heskestad's flame height correlation analysis.

Table 11: Heskestad's flame height correlation analysis.

Heskdestad's Flame Heiaht Correlation V

+

Inputs

Fire diameter [m] 0.6

HRR [kW] 211

Results

Flame height [m] 1.4

Flame height [ft] 4.6

C-35
Step 5a: Identify and Characterize Target Sets: No workshop problem is associated with this

step. The following discussion provides an example of how to identify and characterize target

sets. In practice, this step requires highlighting of cable tray and conduit targets in room layout

drawings based on cable routing analysis and plant walkdowns.

Sample Analysis for Step 5a:

For the purpose of this exercise, let's assume that there are two target sets in the room:

1) HCBT-35A and HCBT-37B, and 2) VCBT-20A, and VCBT-20B. These trays are identified in

Figure 3. The trays have both thermo-set and thermo-plastic cables. Specifically, a fire

damaging either the two horizontal trays or the two vertical trays will generate the postulated

plant condition.

5~' "NO AC"-,

ROOM

VCBT *2CA

Figure 3: Cable tray locations in the switchgear access room

Tray locations:

" HCBT 35A: This horizontal tray comes into the switchgear access room from switchgear

room A. The tray is the second tray in an elevated stack. The lowest tray in the stack is at

elevation 33' (13' from the floor). The target tray, HCBT 35A, is at elevation 35' (15' ft from

the floor and 2' above the lowest tray in the stack).

* HCBT 37B: This horizontal tray comes in the south direction into the switchgear access

room from switchgear room B and turns west. The tray is the first tray in an elevated stack.

It is located at elevation 37' (17' from the floor). At the point the cable tray crosses HCBT

35A, it is the third tray in the stack.

* VCBT 20A: This is a vertical cable tray in the south west corner of the room. The tray

comes into the room through a floor penetration at elevation 20' and runs up to the ceiling.

" VCBT 20B: This is a vertical cable tray in the south west corner of the room. The tray

comes into the room through a floor penetration at elevation 20' and runs up to the ceiling.

C-36
Workshop Problem 1la-04

Step 6a: Define the Fire Scenarios to be Analyzed: Define the fire scenarios to be analyzed

in the switchgear access room using the information provided or collected in the first five steps.

Solution: The following tables and figures describe the fire scenarios defined for analysis. For

the purpose of this exercise, only the scenarios that will be analyzed in detail in upcoming

workshop problems have been defined in detail.

* Fixed ignition source fire scenarios: Fixed ignition source fire scenarios are postulated in

the two closest cabinets to the target trays.

Table 12: Summary of scenario 1.

Scenario 1: A fire in the MCC-A cabinet affecting the two horizontal cable tray targets. The targets could be affected by

hot aas laver temperatures, flame radiation or horizontal flame spread.

Ignition Source MCC-A cabinet. The fire is postulated 1' below the top of the cabinet. The

cabinet is 7' high.

Secondary combustibles Cable tray stack above the electrical cabinet.

Target HCBT-35A, HCBT-37B. The pinch point is located 2' horizontally from the

cabinet (closest distance from fire to pinch point).

Credited detection Automatic fire detection system

Credited suppression Automatic C02 system and fire brigade

Figure 4 provides a pictorial representation of this scenario.

2' HCBT 37Bdet

HCBT 35A Ilcombustibles

MCC Cabinet 17'

13'

7'

Figure 4: Pictorial representation of fire scenario 1. Drawing not to scale.

Table 13: Summary of scenario 2.

Scenario 2: A fire in the 120VAC-A cabinet affecting the two horizontal cable tray targets. The targets could be affected

by hot gas layer temperatures, direct flame radiation, or horizontal flame spread.

Ignition Source 120VAC-A cabinet

Secondary combustibles Cable tray stack above the electrical cabinet.

Target HCBT-35A, HCBT-37B

Credited detection Automatic fire detection system

Credited suppression Automatic C02 system and fire brigade

C-37
Table 14: Summary of scenario 3.

Scenario 3: A fire in the 120VAC-A cabinet affecting the vertical cable tray targets. The targets could be affected by hot

gas layer temperatures, direct flame radiation, or horizontal flame spread..

Ignition Source 120VAC-A cabinet

Secondary combustibles

Target HCBT-35A, HCBT-37B

Credited detection Automatic fire detection system

Credited suppression Automatic C02 system and fire brigade

Finally, Figure 4 illustrates the location of the postulated fires.

+ICfT #35A

VC9T +20X BCU' '371

VCBT '2VA

Figure 5: Pictorial representation of the location of the postulated fire scenarios.

Transient ignition source fire scenarios: Only regular solid transient fire scenarios at floor

level are postulated in this room. Since the room does not contain any mechanical

equipment requiring lubrication or oil, fires resulting from combustible liquid spills are not

postulated.

Table 15: Summary of scenario 4.

Scenario 4: A transient fire at floor level affecting the two horizontal cable tray targets. The targets could be affected by

hot gas layer temperatures, flame impingement or fire plume temperatures.

Ignition Source Floor based transient fire

Secondary combustibles

Target VCBT-20A, VCBT-20B

Credited detection Automatic fire detection system

Credited suppression Automatic C02 system and fire brgade

Figure 6 provides a pictorial representation of this scenario.

C-38
Smoke det

HCBT 35A

Figure 6: Pictorial representation of fire scenario 4. Drawing not to scale.

Table 16: Summary of scenario 5.

Scenario 5: A transient fire at floor level affecting the two vertical cable tray targets. The targets could be affected by

hot gas layer temperatures, flame impingement or direct flame radiation.

Ignition Source Floor based transient fire

Secondary combustibles

Target VCBT-20A, VCBT-20B

Credited detection Automatic fire detection system

Credited suppression Automatic C02 system and fire brigade

Figure 7 illustrate the location of the postulated transient fires.

Figure 7: Pictorial representation of the location of the postulated fire scenarios.

,* Additional scenarios that should be considered include self-ignited cable fires and junction

box fires since this room has unqualified cable.

C-39
Step 7a: Conduct Fire Growth and Propagation Analysis: For the purpose of this workshop,

only two of the fire scenarios listed in the previous section are analyzed in detail: Scenario 1,

and Scenario 4.

Workshop Problem 11a-05:

Determine if a fire in the ignition sources associate with scenarios 1 and 4 can produce room

wide damage in the switchgear access room. If the ignition sources alone are not expected to

generate room wide damage, determine the amount of secondary combustibles necessary to

achieve it.

Solution:

A 1.1 MW fire is necessary for generating room wide damage in the aux switchgear access

room. Using the MQH Room Temperature correlation (NUREG 1805), a 1.1 MW fire may

generate a room temperature of 205 0C, which is the assumed damage temperature (Appendix

H of NUREG/CR-6850) for thermoplastic cables in the aux control room. The aux control room

has approximately 1000 ft2 floor and 20 ft high ceiling. All room surfaces are concrete. The

calculation assumes one single open door and a 20 min fire duration. Table 17 lists the inputs

and output of the MQH room temperature analysis.

Table 17: Summary of room temperature analyses using the MQH model.

MQH Temperature Correlation MQH Temperature Correlation MQH Temperature Correlation

Single cabinet cubicle fire Transient fire Limiting fire size

Inputs Inputs Inputs

Ambient temperature [q] 20 Ambient temperature [C] 20 Ambient temperature [C] 20

Duration [sec] 1200 Duration [sec] 1200 Duration [sec] 1200

Opening area [m2] 2 Opening area [m2] 2 Opening area [m2] 2

Height of opening [m] 2 Height of opening [m] 2 Height of opening [m] 2

Room length [m] 14 Room length [m] 14 Room length [m] 14

Room width [m] 7 Room width [m] 7 Room width [m] 7

Room height [m] 6 Room height [ml 6 Room height [m] 6

Thermal cond [kW/mK] 0.0014 Thermal cond [kW/mK] 0.0014 Thermal cond [kW/mK] 0.0014

Density [kg/m3] 2000 Density [kg/m3l 2000 Density [kg/m3] 2000

Specific heat [kJ/kg] 0.88 Specific heat [kJ/kg] 0.88 Specific heat [kJ/kg] 0.88

Wall thickness [m] 0.6 Wall thickness [m] 0.6 Wall thickness [m] 0.6

HRR [kW] 211 HRR [kW] 317 HRR [kW] 1100

Results •_ Results Results

Room Temp [C] 82 Room Temp [C] 102 Room Temp [C] 205

Both an electrical cabinet and a transient fire are postulated at floor level in the switchgear

access room. Appendix G of NUREG/CR-6850 suggests that the 9 8 th percentile heat release

rates for these fires are 211 kW and 317 kW (see also Table 10). These fire intensities are

lower than the critical value of 1.1 MW calculated earlier required for room wide damage.

Consequently, fire propagation to nearby cable trays or secondary combustibles (if available) is

necessary to reach the critical fire intensity.

C-40
The cable tray heat release rate model described in Chapter 7 of NUREG-1805 suggests a heat

release rate of 265 kW for a 1 m2 for a bench scale HRR of 589 kW/m 2 (PE/PVC material). With

this approximation:

* If the fire starts in an electrical cabinet, approximately 5 trays will need to burn to produce a

1.9 MW fire assuming a 1 m2 of tray on fire: (1100 - 211)/265 = 4 (assuming a tray length of

approximately 3').

" If the fire starts as a transient fire, approximately 6 trays will need to burn to produce a 1.9

MW fire assuming a 1 m2 of tray on fire: (1100 - 317)/265 = 3 (assuming a tray

length of approximately 3').

In the case of self ignited or junction box fires, a total of 1100/265 = 5 trays will need to be on

fire in order to generate room wide damage.,

This analysis will serve as basis for decision making in selecting and analyzing fire scenarios in

the aux control room. In this particular room, it appears that there are not enough trays above

the cabinets or transients where the fire is postulated to generate room wide damage without

significant horizontal flame spread and if suppression activities fail before fire propagates

upward to at least five or six trays.

C-41
Workshop Problem 11a-06

Determine the time to target damage, time to smoke detection, time to automatic suppression

and the fire brigade arrival time for scenario 1.

Solution:

* Time to target damage: Time to target damage is assumed to be: 1) the time required for

the fire to heat up the cable trays to its damage temperature by direct flame radiation, or 2)

the time to room heat up to cable damage temperature. In either case, the fire growth

profile will be an important factor in this analysis.

Heat release rate profile for the ignition source: Table 10, the heat release rate profile for

this ignition source is t

2 grow to a peak of 211 kW in 12 min followed by steady burning for 8

additional minutes. This is the profile recommended in NUREG/CR-6850 for this electrical

cabinet, page G-6.

Heat release rate from secondary combustibles: Recall that the secondary combustibles

(cable tray stack above the panel) is expected to contribute to the fire intensity.

Consequently, the heat release rate profile should include such contribution. Appendix R of

NUREG/CR-6850 describes the following model for fire propagation in cable trays: the first

tray above the ignition source will ignited at the calculated time using fire modeling tools.

The second tray will ignite 4 minutes after the first one. Evaluating the flame height and

plume temperature using the corresponding correlations from Heskestad (Chapters 3 & 9 in

NUREG 1805), both models suggest ignition of the first tray in approximately 3 to 5 min.

Therefore, ignition of the second tray is expected in approximately 9 min after ignition.

Table 18 lists the solution of the correlations as a function of time. Notice that between

times 4 and 5 min, the flame height reaches 1' (the location of the first tray above the

cabinet). At this time however, the plume temperature has exceeded the cable damage

temperature.

Table 18: Summary of Heskestad's flame height and plume temperature analysis as a

function of time.

Time (min) HRR (M) Flame height (ft) Plume Temp (F)

0 0 0.0 68

1 1 0.0 123

2 6 0.0 226

3 13 0.2 380

4 23 0.7 596

5 37 1.2 895

6 53 1.8 1305

7 72 2.3 1871

8 94 2.7 2663

9 119 3.2 3794

10 147 3.7 5458

12 211 4.6 12138

14 211 4.6 12138

16 211 4.6 12138

C-42
Considering that the cables above the cabinet are expected to ignite, the contribution from

the cable tray fire should be included in the analysis. The heat release rate profile listed in

Table 19 is obtained using the cable tray heat release rate model described in Chapter 7 of

NUREG-1 805 with a bench scale HRR of 589 kW/m 2 (PE/PVC material). Notice that the

total heat release rate profile includes the contribution from both, the cabinet fire and the

cable tray fire.

Table 19: Summary of heat release rate profile and room temperature analysis as a

function of time.

Tray width [m]: 0.6

Tray sep [m]: 046

Bench Scale HRR

[kW/m2] 589

Fire HRR for

Length Duration HRR [kW] for electrical cab Total Room

Ignition Source [m] [min] cable trays [kW] HRR [kW] Temp [F]

Electrical cabinet 0 0 0 Ambient

Tray 1 0.6 5 95 37 132 134

Tray 2 1.03 9 164 119 283 187

10 147 311 197

12 211 375 219

14 211 375 223

16 211 375 226

18 211 375 229

20 211 375 232

In the case of room heat up, Table 19 suggests that the fire will not generate hot gas layer

temperatures capable of producing room wide damage. These temperatures were

calculated using the MQH model for room temperature. The results are also consistent with

the analysis in workshop problem 5.

In the case of direct flame radiation, the pinch point is located approximately 2' from the fire.

The point source flame radiation model (see Chapter 5 of NUREG 1805), suggest a

damaging incident heat flux 2' from the ignition source from a fire intensity of 60 kW. This

intensity is lower than the peak calculated earlier and listed in Table 19. A 60 kW fire is

expected somewhere in between 5 and 9 min due to the fire quickly propagating to cable

trays above. The point source flame radiation analysis is documented in Table 20. This

heat flux result bounds the flame spread analysis since the fire at the ignition source location

is capable of impacting the target.

Table 20: Summary of point source flame radiation model analysis

Point Source Flame Radiation Model

Inputs

Fire heat release rate [kW] 60

Radiation fraction 0.40

Distance from flames [m] 0.6

C-43
Results

Heat flux [kW/m2] 5.3

Time to smoke detection:

The time to smoke detection is assumed to be 1 min. The technical basis for this assumption

is as follows: The time to smoke detection listed in Table 21 below are calculated using the

model described in Chapter 11 of NUREG 1805. Notice that for vertical and horizontal

distances from the ignition source in the order of 6 meters, calculated times to detection are

in the order of seconds, which suggests that the 1 min assumption is conservative. The time

to detection calculations were conducted conservatively assuming a low heat release rate of

25 kW. It should be noted that these activation times are not considering any incipient stage

of the fire development, e.g., smoldering.

Table 21: Time to detector activation

Horizontal Radial Distance (m)

Seconds 1 2 3 4 5 6

1 0.5 1.3 2.4 3.9 5.7 7.9

2 0.8 1.3 2.1 3.2 4.5 6.0

P- 3 1.2 1.6 2.2 3.1 4.2 5.4

-, 4 1.6 2.0 2.5 3.3 4.2 5.3

• ? 5 2.1 2.4 2.9 3.6 4.4 5.4

0 M0 6 2.6 2.9 3.4 4.0 4.7 5.6

Time to automatic suppression: Assuming a smoke detection signal in 1 min, and

considering the delay time of 60 for the automatic CO 2 system, the time for automatic

suppression is estimated as 2 min.

Time to fire brigade arrival: The time to fire brigade arrival at the room is estimated as 15

min from brigade drill records.

C-44
Workshop Problem 1la-07

Determine the time to target damage, time to smoke detection, time to automatic suppression

and the fire brigade arrival time for scenario 4.

Solution:

* Time to target damage: Time to target damage is assumed to be: 1) the time required for

the fire to heat up the cable trays to its damage temperature from fire plume exposure, or 2)

the time to room heat up to cable damage temperature, whichever is less. In either case,

the fire growth profile will be an important factor in this analysis.

Heat release rate profile for the ignition source: From Table 10, the heat release rate profile for

this ignition source is t

2 growth to a peak of 317 kW in 12 min followed by steady burning for 8

additional minutes. This is the profile recommended in page G-6 of NUREG/CR-6850 for this

electrical cabinet. Similar to the flame height and plume temperature analysis in workshop

problem 6, Table 22 lists the corresponding results for the transient fire. The results suggest

that the fire will not affect cable trays located 13' above the floor since the plume temperature

does not reach 405 OF.

Table 22: Summary of Heskestad's flame height and plume temperature analysis as a

function of time.

Plume Temp (F) (at

13' above the

Time (min) HRR (kW) Flame height (ft) floor)

0 0 0.0 68

1 2 0.0 72

2 9 0.0 79

3 20 0.5 88

4 35 1.2 98

5 55 1.8 110

6 79 2.4 123

7 108 3.0 137

8 141 3.6 152

9 178 4.1 168

10 220 4.7 186

12 317 5.7 226

14 317 5.7 226

16 317 5.7 226

Time to smoke detection: Time to smoke detection is assumed

results presented in Table 21.

to be 1 min based on the

" Time to automatic suppression: Assuming a smoke detection signal in 1 min, and

considering the delay time of 60 for the automatic C02 system, the time for automatic

suppression is estimated as 2 min.

* Time to fire brigade arrival: The time to fire brigade arrival at the room is estimated as 15

min from brigade drill records.

C-45
Workshop Problem 11a-08

Let's assume that MCC-Al, which is the ignition source in scenario 1 it's a 4160V switchgear.

In this case, a high energy arcing fault event should be also postulated and evaluated.

Determine if the cable tray targets will be within the zone of influence of a high energy arcing

fault.

Solution: The two horizontal trays, HCBT-35A and HCBT-37B are located 6' vertically and 2'

horizontally from the cabinet. According to the criteria listed in pages M-13 and M-14 or

NUREG-CR/6850, the target trays will be outside the zone of influence. However, the stack of

cable trays above the cabinet (the secondary combustibles) will be within the zone of influence,

and therefore, will ignite at time zero. The time to target damage calculated in workshop

problem 6 will be affected due to different ignition time of secondary combustibles.

C-46
Step 8a: Conduct Fire Detection and Suppression Analysis: The detection and suppression is

reflected in the risk analysis with the non-suppression probability, which is calculated using a

Detection/Suppression event tree approach discussed in Appendix P of NUREG/CR-6850,

Detection and Suppression Analysis. Recall that the switchgear access room is equipped with a

smoke detection system, and an automatic CO2 system. The CO2 system has a 60 second

warning alarm delay. In addition to these fixed systems, the fire brigade can also provide manual

suppression activities.

Considering the above fire protection features, the suppression strategy in the switchgear

access room can be summarized as:

1. Indication of smoke detection in control room

2. Control room sends an operator to the switchgear access room to confirm the fire

3. If fire is confirmed, the operator first determines if the automatic CO 2 system operated.

4. If further suppression activities are warranted after any of the automatic systems, manual

suppression by the fire brigade may be used.

Workshop Problem Set 1 la-09

Develop a detection suppression event tree for the fire protection strategy defined above.

Solution:

The above strategy is reflected in the event tree depicted in Figure 8 (similar to the one

described in Appendix P of NUREG/CR-6850). The event tree is then applied to each of the fire

scenarios producing a non-suppression probability for each. The non-suppression probability

results from the summation of the failure to suppress branches in the event tree. The event tree

includes the events listed in Table 23:

Table 23:Events included in the detection suppression event tree

Sequence Detection Suppression

A Prompt detection Prompt suppression

B Prompt detection Automatic suppression

C Prompt detection Fire brigade

D Prompt detection Fire brigade failure

E Prompt detection Fire brigade

F Prompt detection Fire brigade failure

G Automatic detection Automatic suppression

H Automatic detection Fire brigade

I Automatic detection Fire brigade failure

J Delayed detection Fire brigade

K Delayed detection Fire brigade failure

L Delayed detection failure

C-47
Prompt detection and prompt suppression are not credited in the analysis since the switchgear

access room has no continuous fire watch or is equipped with an incipient fire detection system.

Automatic detection is credited since the room has a fire detection system. Fixed automatic

suppression is also credited since the room has an automatic C02 system. Delayed detection is

not credited since time to ignition of the first tray occurs in approximately 7 to 10 min, which is

less than the recommended 15 min for delayed detection in NUREG/CR-6850. Finally, manual

suppression by the fire brigade could be credited but will not have any impact since the C02

release is expected to occur first and the room must remain close during the C02 soak time.

Figure 8: Detection/suppression event tree for the switchgear access room

Prompt Prompt Auto Fixed Delayed Manual

Ignition Detection Suppression Detection Suppression Detection Suppression Branch

A

B

C

D

E

F

G

H

I

J

K

L

C-48
Workshop Problem 11a-10

Step 9a: Calculate Conditional Non-Suppression Probability and Severity Factor:

Determine the severity factor and the non-suppression probability for scenario 1.

Solution:

This scenario consists of a fire propagating to cable trays above. From Table 9, a heat release

rate of approximately 13 to 23 kW (based on plume results) is necessary for a fire to affect the

cables above. For the purpose of this example, a value of 15 kW is selected. Per Table 1, the

ignition source is assigned a Case 3 probability distribution for heat release rate from Table E-1

in NUREG/CR-6850. This is a Gamma distribution with (x = 1.6 and 13 = 41.5. The severity

factor values for heat release rates greater than 15 kW is (using the gamma distribution function

in Microsoft Excel):

SF = 1-GAMMADIST(1 5,1.6,41.5,TRUE) = 0.89

This is interpreted as the probability of a fire spreading to the cable trays above.

Solving the event tree depicted in Figure 8 for a damage time of 5 min, the non suppression

probability is = 0.1. The solution of the event tree is presented in Figure 9. The general inputs

to the event tree are listed in Table 24. Additional inputs to the event tree, developed from the

fire modeling analysis described in the previous step are listed in

C-49
Table 25.

Table 24: General inputs to detection/suppression event tree

Prompt Detection: FALSE

Auto Det: TRUE

Prompt Suppression: FALSE

Fixed Suppression: TRUE

Fixed Supp Type: Automatic

Supp Agent: C02

Delay time (Min): 1

Brigade Arrival (min): 15

Target Damage (min): 5

Det reliability: 0.95

Supp system reliability: 0.95

Traditional Sprinklers: FALSE

HEP: 1

Supp Curve (Table P-3): Electrical Fires

C-50
Table 25: Fire modeling inputs to detection/suppression event tree

Time to (Min)

Ignition: 0

Prompt Det: 0

Prompt Supp: 0

Auto Det: 1

Fixed Supp: 2

Delayed Det: 15

Target Damage (min): 5

Figure 9: Solution of the detection/suppression event tree

Branch

A

B

C

D

E

F

G

H

J

K

L

PNS

Branch

Probability

0.OE+00

0.OE+00

4.8E-02

0.0E+00

5.OE-02

0.098

1

C-51
Workshop Problem 11a-11

Step lOa: Calculate Scenario Frequency: Using the ignition frequency calculated in Task 6

for the ignition sources in the switchgear access room, and the severity factor and nonsuppression probability calculated in the previous step for scenario 1, determine the frequency

for fire- scenario 1.

Solution:

Recall that this scenario consists of a fire propagating to a cable tray stack above and

generating target damage due to direct flame radiation. This sequence of events is captured in

the event tree depicted in Figure 10.

* The first event is the ignition frequency calculated in Task 6 of the Fire PRA as documented

in NUREG/CR-6850.

* The second event refers to the fire propagating to the cable tray stack above. The

probability of propagating is given by the severity factor calculated in Step 9.

* The third event is defined by the probability of suppressing the fire before target damage, as

calculated earlier in Step 9.

Only one outcome in the event tree refers to cable damage before suppression. The frequency

of this outcome is 8.8E-5.

Figure 10: Event tree depicting the sequence of events leading to target damage

Propagation to cable Suppression fails

Ignition Frequency trays above before target damage" Frequency Outcome

0.1 8.8E-05 Damage

Yes

0.89

Yes

No

= 9.9E-3(3/30) = 9.9E-04 0.9 7.9E-04 Damage

No

No

0.11 1.1E-04 Damage

No

C-52
Session 11b: Example Problems (Main Control Room Fire Analysis)

C-53
Workshop Problems for Task 11 b: Detailed Fire Modeling in the Main

Control Room

Workshop Problem Set 11b-02 (Solution)

Step 2.b: Estimate Control Room Fire Frequency: Using the information provided in this

Sample Package, and the above formula copied from NUREG/CR 6850, estimate the frequency

of fire for the SNPP MCR.

WL, MCR = 1

There is only one unit and one MCR for the unit.

,MCB = 2.5E-03

From Table 6-1 of NUREG/CR 6850, bin # 4

WPWC, Elec. Cab, MCR. = 7.4E-03

From Results of Task 6 Problem Set 06-09

kPWC, Elec. Cab. = 4.5E-02

From Table 6-1 of NUREG/CR 6850, bin # 15

Wtransients, MCR = 0.64

From Task 6 Calculations

,transient = 3.9E-03

From Table 6-1 of NUREG/CR 6850, bin # 7

Wwelding, MCR = 0.2

From Task 6 Calculations

kwelding = 9.7E-03

From Table 6-1 of NUREG/CR 6850, bin # 6

WCable,MCR: = 0.35

From Task 6 Calculations

kcable = 1.6E-03

From Table 6-1 of NUREG/CR 6850, bin # 5

per N/A

per reactor year

per N/A

per reactor year

per N/A

per reactor year

per N/A

per reactor year

per N/A

per reactor year

XMCR = 1 x (2.5E-03 + 7.4E-03 x 4.5E-02 + 0.64 x 3.9E-03 + 0.2 x 9.7E-03 + 0.35 x 1.6E-03 =

= 2.5E-03 + 3.3E-04 + 2.5E-03 + 1.9E-03 + 5.6E-04 = 7.79E-03 per reactor year

C-54
Workshop Problem Set 11b-05 (Solution)

Step 5.b: Identify and characterize target sets: Identify at least five target sets for the Main

Control Room by inspecting drawings DWG A-07 and A-09 and other information provided in

this Sample Package.

Target Set Items in the target set Basis for selecting target set

ID

MCR-01 Control room habitability Of potential scenarios involving control room

abandonment without any damage to the Main

Control Board, a fire in the kitchen could be severe

enough forcing the operators out.

MCR-02 Service water controls Service water and CCW are controlled from a small

part of the Main Control Board. A fire within CB-7

may fail both systems. Loss of Service Water alone,

may have a significant CCDP.

MCR-03 HPI-A High pressure safety

injection pump A

HPI-B High pressure safety

injection pump B

RHR-B RHR pump

AOV-2 (SOV-2) Letdown

isolation valve

AOV-3 (SOV-3) Charging

pump injection valve

MOV-1 HPI valve

MOV-2 VCT isolation valve

MOV-3 Cont. sump recirc

valve

MOV-4 Cont. sump recirc

valve

MOV-5 RWST isolation

valve

MOV-6 RWST isolation

valve

MOV-7 RHR inboard suction

valve

MOV-8 RHR outboard

suction valve

MOV-9 HPI valve

LI-1 RWST level

LI-2 RWST level

LI-3 Cont. sump level

LI-4 Cont. sump level

TI-1 Letdown heat

exchanger outlet

temp

CB-5 contains a large number of safety related

component controls. A fire limited to this part of the

panel, affecting the equipment controlled from this

panel may have a significant CCDP.

C-55
Target Set Items in the target set Basis for selecting target set

ID

MCR-04 AFW-A Motor driven AFW CB-3 contains all post shutdown secondary cooling

pump A equipment controls. A fire limited to this part of the

AFW-C Motor driven AFW panel, affecting the equipment controlled from this

pump C panel may have a significant CCDP.

MOV-1 0 AFW discharge

valve

MOV-1 1 AFW discharge

valve

MOV-14 AFW turbine steam

line isolation valve

MOV-1 5 AFW steam inlet

throttle valve

MOV-16 AFW test line

isolation valve

MOV-17 AFW test line

isolation valve

MOV-18 AFW C Pump

Discharge

MOV-19 AFW test line

isolation valve

A-1 AFW motor high

temp

MCR-05 HPI-A High pressure safety

injection pump A

HPI-B High pressure safety

injection pump B

AOV-2 (SOV-2) Letdown

isolation valve

MOV-2 VCT isolation valve

LI-3 Cont. sump level

LI-4 Cont. sump level

AFW-A Motor driven AFW

pump A

AFW-C Motor driven AFW

pump C

MOV-14 AFW turbine steam

line isolation valve

MOV-1 5 AFW steam inlet

throttle valve

The shortest distance between the controls of the HPI

and AFW systems that can render the pumps from

both system inoperable is the distance from MOV-15

control switch to HPI-A control switch. Loss of both

systems may have a significant CCDP.

C-56
Workshop Problem Set 11b-06 (Solution)

Steps 6.b: Identify and Characterize Ignition Sources:

Steps 7.b: Define Fire Scenarios: For the target sets provided in the solution of the preceding

problem set, identify the corresponding ignition sources. and fire scenarios.

Target Set ID Ignition Sources Fire Scenarios

MCR-01 1. Water heater in the kitchen MCR-01.1. An electrical short in the water heater leads to a

fire in the kitchen that becomes severe enough to lead to

control room abandonment.

2. Microwave oven in the kitchen MCR-01.2. An electrical short in the microwave oven or a

food item fire inside the oven leads to a fire in the kitchen

that becomes severe enough to lead to control room

abandonment.

MCR-02 1. Main Control Board - Fire in MCR-02.1. A fire inside Main Control Board due to internal

CB-7 causes. The fire initiates inside CB-7. Operator response

in putting the fire is not fast enough to prevent damage to

CB-7 contents. But the fire is controlled before it

propagates to other parts of the panel.

2. Transient fire MCR-02.2 A transient fire inside Main Control Room, but

outside the Main Control Board, occurs near CB-7 such that

only CB-7 is affected either because of the location of the

fire or fire fighting efforts.

3. Transient fire due welding and MCR-02.3. A transient fire due to welding and cutting inside

cutting Main Control Room, but outside the Main Control Board,

occurs near CB-7 such that only CB-7 is affected either

because of the location of the fire or fire fighting efforts.

4. Cable fire due welding and MCR-02.4. A cable fire occurs due to welding and cutting

cutting. inside Main Control Board occurs near CB-7 such that only

CB-7 is affected because fire fighting efforts limit the reach

of the fire.

MCR-03 1. Main Control Board - Fire in

CB-5

MCR-03.1. A fire inside Main Control Board due to internal

causes. The fire initiates inside CB-5. Operator response

in putting out the fire is not fast enough to prevent damage

to CB-5 contents. But the fire is controlled before it

propagates to other parts of the panel.

2. Transient fire MCR-03.2. A transient fire inside Main Control Room, but

outside the Main Control Board, occurs near CB-5 such that

only CB-5 is affected either because of the location of the

fire or fire fighting efforts.

3. Transient fire due welding and MCR-03.3. A transient fire due to welding and cutting inside

cutting Main Control Room, but outside the Main Control Board,

occurs near CB-5 such that only CB-5 is affected either

because of the location of the fire or fire fighting efforts.

C-57
Target Set ID Ignition Sources Fire Scenarios

4. Cable fire due welding and MCR-03.4. A cable fire occurs due to welding and cutting

cutting. inside Main Control Board occurs in CB-5 such that only

CB-5 is affected because fire fighting efforts limit the reach

of the fire.

MCR-04 1. Main Control Board - Fire in MCR-04.1. A fire inside Main Control Board due to internal

CB-3 causes. The fire initiates inside CB-3. Operator response

in putting the fire is not fast enough to prevent damage to

CB-3 contents. But the fire is controlled before it

propagates to other parts of the panel.

2. Transient fire MCR-04.2. A transient fire inside Main Control Room, but

outside the Main Control Board, occurs near CB-3 such that

only CB-3 is affected either because of the location of the

fire or fire fighting efforts.

3. Transient fire due welding and MCR-04.3. A transient fire due to welding and cutting inside

cutting Main Control Room, but outside the Main Control Board,

occurs near CB-3 such that only CB-3 is affected either

because of the location of the fire or fire fighting efforts.

4. Cable fire due welding and MCR-04.4. A cable fire occurs due to welding and cutting

cutting. inside Main Control Board occurs in CB-3 such that only

CB-3 is affected because fire fighting efforts limit the reach

of the fire.

MCR-05 1. Main Control Board - Fire MCR-05.1. A fire inside Main Control Board due to internal

starting either in CB-3 or in CB-5 causes. The fire initiates inside CB-3 or CB-5. Operator

response in putting the fire is not fast enough to prevent

damage to the postulated target set. But the fire is

controlled before it propagates to other parts of the panel.

2. Transient fire MCR-05.2. A transient fire inside Main Control Room, but

outside the Main Control Board, occurs near CB-3 and CB-5

such that only the postulated target set is affected either

because of the location of the fire or fire fighting efforts.

3. Transient fire due welding and MCR-05.3. A transient fire due to welding and cutting inside

cutting Main Control Room, but outside the Main Control Board,

occurs near CB-3 and CB-5 such that only the postulated

target set is affected either because of the location of the

fire or fire fighting efforts.

4. Cable fire due welding and MCR-05.4. A cable fire occurs due to welding and cutting

cutting. inside Main Control Board occurs in CB-3 or CB-5 such that

only the postulated target set is affected because fire

fighting efforts limit the reach of the fire.

C-58
Workshop Problem Set 11b-07 (Solution)

Step 8b: Conduct Fire Growth and Propagation Analyiss

Step 9b: Detection and Suppression Analysis and Severity Factor: Using the information

provided in the solution to Problem Sets 1 lb-05 and 06 and Figure L-1, conduct fire propagation,

detection and suppression analysis for the following fire scenarios and calculate scenario

frequency:

MCR-03.1

The farthest distance between the postulated control devices on the board is 4 ft.

d =4ft= 1.2 m

Assumed non-qualified cables since a portion of the cables are non-qualified.

From Figure L-1 it is concluded:

[SFXPNs]MCR-03.1 = 3.OE-03

XMCR-03.1 = 2.5E-03 x 3.OE-03 = 7.5E-06 per reactor year

MCR-04.1

The farthest distance between the postulated control devices on the board is 2 ft.

d=2ft=0.6m

Assumed non-qualified cables since a portion of the cables are not qualified.

From Figure L-1 it is concluded:

[SFxPNs]MCR-04.1 = 5.OE-03

XMCR-04.1 = 2.5E-03 x 5.OE-03 = 1.25E-05 per reactor year

C-59

NRC FORM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

(9-2004) (Assigned by NRC, Add Vol., Supp., Rev.,

NRCMD 3.7 and Addendum Numbers, If any.)

BIBLIOGRAPHIC DATA SHEET

(See instructions on the reverse) NUREG/CP-0194 Volume 3

2. TITLE AND SUBTITLE 3. DATE REPORT PUBLISHED

MONTH YEAR

Methods for Applying Risk Analysis to Fire Scenarios (MARIAFIRES) - 2008, July 2010

NRC-RES/EPRI Fire PRA Workshop, Volume 3 - Module 3: Fire Analysis

4. FIN OR GRANT NUMBER

5. AUTHOR(S) 6. TYPE OF REPORT

Conference Proceedings

Compiled and edited by D. Stroup, F. Gonzalez, and H. Woods (NRC)

7. PERIOD COVERED (Inclusive Dates)

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (If NRC, provide Division, Office or Region, U.S. Nuclear Regulatory Commission, and mailing address; if contractor,

provide name and mailing address.)

U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research (RES), Washington, DC 20555-0001

Electric Power Research Institute (EPRI), 3420 Hillview Avenue, Palo Alto, CA 94303

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (If NRC, type "Same as above'; if contractor, provide NRC Division, Office or Region, U.S. Nuclear Regulatory Commission,

and mailing address.)

U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research (RES), Washington, DC 20555-0001

Electric Power Research Institute (EPRI), 3420 Hillview Avenue, Palo Alto, CA 94303

10. SUPPLEMENTARY NOTES

NRC-RES/EPRI Fire PRA Workshops conducted Sept. 28 - Oct. 2, 2008 and Nov. 17-20, 2008 in Bethesda, MD

11. ABSTRACT (200 words or less)

The U.S. Nuclear Regulatory Commission (NRC) approved the risk-informed and performance-based alternative

regulation 10 CFR 50.48(c) in July 2004, which allows licensees the option of using fire protection requirements

contained in the National Fire Protection Association (NFPA) Standard 805, "Performance Based Standard for Fire

protection for Light-Water Reactor Electric Generating Plants, 2001 Edition," with certain exceptions. To support

licensees' use of that option, the NRC and the Electric Power Research Institute (EPRI) jointly issued NUREG/CR-6850

(EPRI 1011989) "Fire PRA Methodology for Nuclear Power Facilities," in September 2005. That report documents the

state-of-the-art methods, tools, and data for conducting a fire Probabilistic Risk Assessment (PRA) in a commercial

nuclear power plant (NPP) application. Since the release of NUREG/CR-6850 in 2005, the NRC-RES and EPRI have

conducted a number of joint public workshops to provide training in the use of the methodologies and tools contained in

the document. The workshops have attracted both domestic and international. The material in this NUREG/CP was

recorded during two workshops conducted in 2008. It was adapted by NRC-RES Fire Research Branch (FRB) members

for use as an alternative training method for those who were unable to physically attend the training sessions. This reporl

can also serve as a refresher for those who attended one or more training sessions, and would be useful preparatory

material for those planning to attend a session.

12. KEY WORDS/DESCRIPTORS (List words or phrases that will assist researchers in locating the report.) 13. AVAILABILITY STATEMENT

unlimited

fire, performance-based, risk-Informed regulation, fire hazard analysis (FHA), fire safety, 14. SECURITY CLASSIFICATION

fire protection, nuclear power plant, probabilistic risk assessment (PRA), fire modeling, circuit (This Page)

analysis unclassified

(This Report)

unclassified

15. NUMBER OF PAGES

16. PRICE

NRC FORM 335 (9-2004) PRINTED ON RECYCLED PAPER

Export Control Restrictions

Access to and use of this report is granted with the specific

understanding and requirement that responsibility for ensuring

full compliance with all applicable U.S. and foreign export

laws and regulations is being undertaken by you and your

company. This includes an obligation to ensure that any

individual receiving access hereunder who is not a U.S.

citizen or permanent U.S. resident is permitted access under

applicable U.S. and foreign export laws and regulations. In

the event you are uncertain whether you. or your company

may lawfully obtain access to this report, you acknowledge

that it is your obligation to consult with your company's legal

counsel to determine whether this access is lawful. Although

EPRI may make available on a case-by-case basis an informal

assessment of the applicable U.S. export classification for

specific report, you and your company acknowledge that this

assessment is solely for informational purposes and not for

reliance purposes. You and your company acknowledge that

it is still the obligation of you and your company to make your own assessment of the applicable U.S. export classification

and ensure compliance accordingly. You and your company

understand and acknowledge your obligations to make a

prompt report to EPRI and the appropriate authorities

regarding any access to or use of this report hereunder that

may be in violation of applicable U.S. or foreign export laws

or regulations.

Electric Power Research Institute and EPRI are registered service marks of

the Electric Power Research Institute, Inc.

Printed on recycled paper in the United States of America

EPRI 1020621

The Electric Power Research Institute (EPRI)

The Electric Power Research Institute (EPRI), with major locations in

Palo Alto, California, and Charlotte, North Carolina, was established

in 1973 as an independent, nonprofit center for public interest

energy and environmental research. EPRI brings together members,

participants, the Institute's scientists and engineers, and other leading

experts to work collaboratively on solutions to the challenges of electric

power. These solutions span nearly every area of electricity generation,

delivery, and use, including health, safety, and environment. EPRI's

members represent over 90% of the electricity generated in the

United States. International participation represents nearly 15% of

EPRI's total research, development, and demonstration program.

Together...Shaping the Future of Electricity

United States Nuclear Regulatory Commission

Washington, D.C.

NUREG/CP - 0194

ELECTRIC POWER RESEARCH INSTITUTE

3420 Hillview Avenue, Palo Alto, California 94304-1395 • PO Box 10412, Palo Alto, California 94303-0813 USA

800.313.3774 * 650.855.2121 * askepri@epri.com • www.epri.com