URCEG/CR447O BNbN#UHEIO•5IO4f

THE USE OF A FIELD MODEL TO ASSESS FIRE BEHAVIOR

IN COMPLEX NUCLEAR POWER PLANT ENCLOSURES:

PRESENT CAPABILITIES AND FUTURE PROSPECTS

John L. Boccio and John L. Usher

December 1985

RELIABILITY & PHYSICAL ANALYSIS GROUP

DEPARTMENT OF NUCLEAR ENERGY, BROOKHAVEN NATIONAL LABORATORY

UPTON, NEW YORK 11973

ilipruk I

Prepared for

United States Nuclear Regulatory Commission

Washington, D.C. 20555

U. S. NUCLEAR REGULATORY OO"S3ION

L1BRARY

WASHI-NGTON DQ ZXU ,

STOP 55•4..

NUREG/CR-4479

BNL-NUREG-51948

AN. R-7

THE USE OF A FIELD MODEL TO ASSESS FIRE BEHAVIOR

IN COMPLEX NUCLEAR POWER PLANT ENCLOSURES:

PRESENT CAPABILITIES AND FUTURE PROSPECTS

J.L. Boccio and J.L. Usher

Manuscript Completed - November 1985

Date Published - December 1985

RELIABILITY AND PHYSICAL ANALYSIS GROUP

DEPARTMENT OF NUCLEAR ENERGY

BROOKHAVEN NATIONAL LABORATORY

UPTON, N.Y. 11973

Prepared for

DIVISION OF ENGINEERING TECHNOLOGY, RES

OFFICE OF NUCLEAR REGULATORY RESEARCH

U.S. NUCLEAR REGULATORY COMMISSION

WASHINGTON, D.C. 20555

UNDER CONTRACT DE-AC02-76CH00016

FIN A-3252
NOTICE

This report was prepared as an account of work sponsored by an agency of the United

States Government. Neither the United States Government nor any agency thereof, or

any of their employees, 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 this report, or represents

that its use by such third party would not infringe privately owned rights.

The views expressed in this report are not necessarily those of the U.S. Nuclear

Regulatory Commission.

Available from

Superintendent of Documents

U.S. Government Printing Office

P.O. Box 37082

Washington, DC 20013-7982

and

National Technical Information Service

Springfield, Virginia 22161
-iiiABSTRACT

This report provides a summary of the work conducted during FY-1984 by

Brookhaven National Laboratory (BNL), under FIN A-3252 "Fire Protection Research

Program." It was undertaken under the cognizance of the Electrical Engineering

Branch in the Division of Engineering Technology within the Office of Nuclear

Regulatory Research. The report describes a mathematical model for predicting

the thermal environment within complex nuclear power plant enclosures. It demonstrates the capability of the existing numerical code by direct comparisons

with electrical cable fire/large enclosure tests performed by Sandia National

Laboratories (SNL) for the NRC and by the Factory Mutual Research Corporation

(FMRC) for the Electric Power Research Institute (EPRI). It further demonstrates the potential usefulness of the existing code in addressing fire-protection issues. This is done through a parametric study of the thermal environment

resulting from a series of fires within cabinets in a nuclear power plant control room (similar to LaSalle). Also, it presents an example of how the code

can be utilized by addressing an Appendix R exemption request which deals with

the vulnerability of containment fans to a fire emanating from a reactor coolant

pump bay. Recommendations are also given as to how the model/code can be further enhanced and where current effort is proceeding.
-ivACKNOWLEDGEMENT

This work was performed for the Electrical Engineering Instrumentation and

Control Branch (EEICB) of the U.S. Nuclear Regulatory Commission. Dr. Amar

Datta of EEICB was the technical monitor of the project and the authors wish to

acknowledge him for providing useful guidance and comments throughout the course

of this program. Special thanks go to our subcontractor, CHAM of North

America, and especially this organization's technical director, Dr. Ashok

Singhal. The use of this organization's proprietary code, PHOENICS, was the

basis for the numerical predictions present herein.

Finally, the authors wish to acknowledge our secretary, Ms. Jeanne Danko,

without whose dedicated efforts and attention to detail this report would not

have been completed in a timely fashion.
CONTENTS

Pagge

ABSTRACT ...................................................... iii

ACKNOWLEDGEMENT .................. ......................................... iv

LIST OF TABLES ........................................................... v

LIST OF FIGURES ....................................... vii

EXECUTIVE SUMMARYo .................................... ix

I. INTRODUCTION ...................... I

A. Background: Fire Protection Safety Issues and Program Overview... 1

B. Study Obetvs......................... 2

II. FIRE PROTECTION PROJECT DESCRIPTION ................................... 4

A. Fire Source Characterization(FSC)............................... 4

B. Fire Environment Determination (FED)............................. 4

C. Control Room Habitability and Fire Safety Study CCR)............. 7

III. BNL PROJECT SUMMARIES................................................ 8

A. Fire Source Characterization Program............................. 8

B. Fire Environment Determination Program........................... 18

C. Control Room Habitability and Fire Safety Study Program.......... 39

D. Plant Specific Code Application.................................. 42

IV. FUTURE DIRECTIONS - BVL ............................................... 50

A. Validation with Cabinet/Control Room Test Data ........ 0.......... 50

B. Parametric Study of Fires Within NPP Control Rooms ............... 50

V. CONCLUSIONS ....................................... 51

REFERENCES ...... o..................................... 52
-viLIST OF TABLES

Table Page

1. Generic Enclosures Survey. ........ ........ 11

2. Exchange Coefficients (ro) and Source Terms (SO) for Different

SVariables ......... .. .......................... ..... 0 ...... 0 4....... 21
-viiLIST OF FIGURES

Fig. No. Title Page

1. Code Comparison Matrix............................................. 19

2. Three-Dimensional View of FMRC Test Structure...................... 23

3. Velocity Vector Field Through Central Vertical Plane During

Fire Growth................................................ ...... 26

4. Isotherm Contours (T=50*C, T=60*C) at 240 secs. Into Fire.*........ 27

5. Fire Enclosure Details: Preliminary Fire Experiments Number

2 and 3 and Full-Scale Tests 1 and 2 ...................... 28

6. Grid Distributions, Coordinate Directions and Thermocouple

Positions (Shown by "X)......................................... 29

7. Total Heat Release Rates for Experiments 2 & 3, and Tests I & 2.... 30

8. Heat Release Rate for Experiment 2 ................................. 30

9. Volumetric Heat Release and Heat Loss Distributions ................ 30

10. Calculated Development of Doorway Velocity and Temperature

Profiles for Experiment 3........................................ 32

11. Measured Doorway Profiles in Steckler's (NBS) Steady-State

Experiments ...................................................... 32

12. Predicted and Measured Temperatures for Experiments 2 and 3........ 33

13. Predicted and Measured Temperatures at Several Levels for

Experiment Measue T....emperture atSeveral.r....... 33

14. Predicted and Measured Temperatures at Several Levels for

Experiment 3 .se.......... , ................... 33

15. Predicted and Measured Temperatures at Several Levels for

Experiment 3...........................33

16. Velocity Distributions in Two Longitudinal Vertical Planes

(Experiment 2) ............................................. 34

17. Predicted and Measured Temperatures at 1' Below Ceiling and

2' from the Tray (Test 1) ........................................ 35
-viiiLIST OF FIGURES (Cont'd)

Fig. No. Title Page

18. Predicted and Measured Temperatures at Redundant Target (Test 1)... 35

19. Predicted and Measured Temperatures at 1' Below Ceiling and

2' from the Tray (Test 2) ........................................ 35

20. Predicted and Measured Temperatures at Redundant Target (Test 2)... 35

21. Predicted and Measured Temperatures at Several Locations for

Test 1* .............................................. 36

22. Predicted and Measured Temperatures at Several Locations for

Test 1........................................................... 36

23. Stratified Hot Layer Development for Experiment 3 ................. 37

24. Stratified Hot Layer Development for Test 1 ........................ 38

25. Horizontal Cross-Section ................. ........ ...... .. ....... 39

26. Valance Horizontal View ............................. 40

27. Velocity Distributions in Horizontal Plane IZfl at t=360 so..*....... 42

28. Development of Temperature Field at Various Times .... 0........... 43

29. Containment Model Geometry ....... .............. .... ... . .. ..... 45

30. Flow Vectors Plotted on a 2-D Cross-Section of the Containment

Building. The vectors are magnified seven times for details.

Inflow at the RCP Bay Base is 1 m/so.............................. 46

31. Containment Temperature Profile at end of Variously Sized Lube

Oil Fires ....................... o .........*............. 48

32. Lines of Constant Temperature in the Containment Building After

the Postulated Fire. The Contours Range from 386K to 450K

in 2K Increments ............................... o.................. 49
-ixEXECUTIVE SUMMARY

A. BACKGROUND

For the past several years research in fire protection measures and fire

safety conducted by the U.S. Nuclear Regulatory Commission (NRC) has focused on

providing technical bases upon which specific deterministic requirements for

fire protection could be established. The requirements, buffered by these research activities, are contained in Appendix R to 10CFR50 and in Section 9.5.1

of the Standard Review Plan (SRP). These criteria/guidelines indicate the minimum necessary fire protection measures and features such as separation by fire

barrier or distance, automatic fire detection and suppression, and system redundancy to limit fire damage while not impairing those engineered safety features

designed to safely shut down the plant.

Efforts by utilities in either complying with or seeking exemption from

these requirements have largely relied on the use of analytical fire models to

provide justification to their proposed fire-safety design changes or to indicate that existing features conservatively comply with the overall fire safety

mandates. In the course of evaluating these analyses, the NRC must judge

whether they incorporate state-of-the-art models and recent test results. Particular attention must be given to ensure that the application of the models is

consistent with the assumptions and limitations of the particular unit-problem

fire models employed in the fire hazards analysis.

The scope of these reviews entail answers to the following questions:

" Are the fire scenarios analyzed reflective of what may realistically occur? In other words, does the physical model employed represent an adequate and conservative replication of the major fire-related phenomena.

" Concomitantly, does the mathematical model adequately portray these

major physical processes and geometrical constraints?

• Does the actual scenario bound the overall problem?

" Are the conclusions drawn from the calculated results uniformly valid

with the assumptions made to provide a tractable analysis?

Responding to these questions as well as other "fire damage" issues which have

been raised indicates a need for NRC to develop a computational capability to

determine the margins of safety inherent in various fire protection features and

layouts in nuclear power plants (NPPs).

Also, reflecting upon the increasing emphasis and use of probabilistic

techniques in the assessment of NPP risk in general, and the risk due to internal fires in particular, further indicates a need to develop a fire-scenario

modeling capability. Only recently has the probabilistic analysis of internal
fires become an accepted, albeit immature, part of full-scale Probabilistic Risk

Assessment (PRA) studies. The more difficult aspects of the probabilistic analysis occur in estimating the likelihood that equipment will be disabled by a

fire. This problem is compounded by the existing uncertainties in

deterministic/probabilistic modeling of detection and suppression systems, the

stochastic nature of fire growth over time, and the size and geometric complexity of the fire zone wherein hot gases can cause equipment failure or induce

secondary fires.

A number of important models have been developed over the years to assist

the analyst in calculating the likely progression of a fire, but in even the

simplest cases the quantitative uncertainties remain large. Available firegrowth and fire-enclosure models are highly approximate in character and are not

capable of accurately modeling the fire-induced environment in a compartment of

crowded objects situated in a unique configuration. Also, the analysis of failure modes for components exposed to the whole spectrum of combustion products

(heat, smoke, toxic aerosols) needs more methodological development enhanced by

test data. Methods must also be developed for treating the intercompartmental

spread of fire and combustion products.

The need for conducting fire testing in complex, large test enclosures that

contain flow obstacles, prototypic fire-sensitive equipment, and house forced

ventilation systems requires that a computational capability be developed to

economically scope a fire-test program.

For the NRC to determine how fire safe nuclear power plants are, how much

fire-safety improvement, if any, is required, and how the desired level of fire

safety can be ensured during the lifetime of the plant more sophisticated and

phenomenologically complete mathematical tools must be developed to assist them

in their regulatory, decision-making process.

B. SUMMARY OF EFFORTS

As a continuation of a research project initiated in FY 1982, prior efforts

entailed surveys of both national and international research programs which

could be a factor in formulating nuclear power plant fire protection programs

and guidelines. Keeping abreast of these fire-protection research programs

undertaken by the fire-science community and apprising NRC of the results, conclusions, and possible implementation into NRC's decision-making process (as it

relates to fire-safety issues) provided the necessary background and experience

to complete a survey of enclosure fire models that specifically employ threedimensional, transient field model techniques. Also, understanding NRC needs in

nuclear power plant fire safety and the issues raised allowed BNL to develop

criteria for selecting one of these modeling approaches which has the potential

for analyzing the fire-induced environment in enclosures typical of NPP critical

areas.
-xiBased on the criteria established, a computational model was selected.

Efforts in FY 1984, summarized in this report, were scoped to demonstrate

further the capability of the selected analytical model/numerical code. This

largely entailed comparisons with cable fire/enclosure tests conducted for the

Electric Power Research Institute (EPRI) and for the NRC. The former test program was performed by the Factory Mutual Research Corporation (FMRC) in their

intermediate scale facility; the latter was performed for Sandia National Laboratories in their investigation of spatial separation as a fire protection method. Comparisons with both test programs are promising to the extent that the

model-demonstration phase is essentially complete and model enhancement can

proceed.

This report also describes the effort started in FY 1984 in which a parametric study of potential fire environments within nuclear power plant control

room configurations was conducted. This work was undertaken to provide additional fire-modeling capability to those fire-risk tasks associated with NRC's

Risk Methodology, Integration, and Evaluation (RMIE) Program. As such, preliminary efforts have been directed toward numerical investigation of potential

fire scenarios in the LaSalle NPP control room. Prefatory analysis of the fire

environment within the LaSalle Control Room, caused by a fire within a control

cabinet is documented in this report also. The results are indeed promising,

and the ensuing thermal environment is physically plausible.

In addition to numerical comparisons of enclosure fire tests involving

electrical cables and parametric studies of cabinet fires within realistic complex control-room configurations, this report presents numerical comparisons of

the effects of a reactor coolant pump lube oil fire within a particular plant

containment building. This latter demonstration emphasizes the value of the

mathematical model as a tool which can be used by NRC in their review of licensee Appendix R exemption requests.

C. RECOMMENDATIONS

Based upon favorable comparisons with experiments and the plausible results

from parametric studies and case-specific Appendix R exemption requests, this

report details future directions in model improvement which can further enhance

its usefulness in addressing fire protection and fire risk issues. In this regard, it is recommended that effort should continue in the following three

areas:

1. Further adapt the three-dimensional field model in order to incorporate within the numerical code additional energy generation and heat

exchange mechanisms. Energy generation mechanisms to be included in

the multi-component aspects of the mathematical model should contain

those features which account for the afterburning of pyrolysis products. To keep the analytical modeling tractable, emphasis should be

placed on employing a simple, existing chemical-reaction scheme or a

one-step quasi-global gaseous reaction mechanism, coupled with a
-xiicombustion-inefficiency parameter. This presupposes that input to the

code will include mass fractions of the major reactant products.

Heat exchange mechanisms, notably losses due to conduction and radiation, should also be modeled. However, these loss mechanisms (or

thermal energy transfer mechanisms) are to be treated in an ancillary

manner and coupled to the conservation equations through a unit-problem approach. For example, instead of using relations directly linked

to the general governing equations, constitutive unit models will be

employed which are somewhat decoupled from the convective and diffusive exchange processes. Thus, radiative heat transfer could be

treated by linking zone models to the field model, employing view

factors and global energy transfer considerations. This will allow

global radiation transfer from the hot gas layer and the flame zone to

selected targets to be determined simply.

This model enhancement can be used in the design of a fire-test experimental program and could assist SNL's fire-research efforts by identifying the parameters, instrumentation locations, relevant fire locations, etc., for their test program.

2. Apply the upgraded model, at an appropriate level of development, to

complete the parametric study (started in FY 1984) to investigate potential fire environments in the LaSalle Plant control room. The parametric study and model development should be initially tied directly

to existing NRC concerns for this type of fire area, e.g., control

room habitability during the early stages in the developing fire.

Means for appraising final room-damage states and plant operability

from the control room after the fire has been extinguished will also

be key modeling features that should be examined. Fire suppression

activities (manual/automatic) can be modeled during this effort.

Detection/suppression models can be augmented into the existing code/

mathematical model.

3. In addition to parametric studies of control room environment, given a

selected series of realistic initiating fires, the upgraded model

should be used to predict potential fire environments in other nuclear

power plant enclosures. As potential support to the fire-risk tasks

of the RMIE Program (FIN A-1391) initial guidance for choosing other

enclosure/geometries will come from the critical fire area screening

analyses to be conducted for the LaSalle plant.

This report indicates that continued future efforts should be conducted

with the existing code and its adaptations through parametric studies of critical fire areas and identified by screening analyses performed through "externalevent" risk studies. By the example applications described in this report, however, the results show that at its present stage of development, the model/code

can be a useful adjunct to NRC's decision-making process in addressing firesafety issues.
-1-

I. INTRODUCTION

A. BACKGROUND: FIRE PROTECTION SAFETY ISSUES AND PROGRAM OVERVIEW

Appendix R to 10 CFR Part 50 and the Branch Technical Position CMEB 9.5-1

establish the fire damage limits to systems associated with achieving and maintaining safe hot shutdown condition of the nuclear reactor as follows:

"One train of equipment necessary to achieve hot shutdown from either the

control room or emergency control station(s) must be maintained free of

fire damage by a single fire, including an exposure fire."

This is interpreted as a clear requirement to maintain at least one of the redundant trains of safe hot shutdown equipment in continued operable condition,

even after exposure to a fire or a fire environment. Section IIIG of Appendix R

and Section C5.b of the BTP spell out three options available to the licensee to

meet this requirement, one of which is the "20-ft separation" option. The

licensee may meet the requirement of maintaining a hot shutdown capability by

separating the redundant trains by a horizontal distance of more than 20 ft,

with no intervening combustibles or fire hazards, provided that fire detectors

and an automatic fire suppression system are also installed in the fire area.

The Office of Nuclear Reactor Regulation requested a series of tests to ascertain the adequacy of the 20-ft separation option. Full-scale replications of

a nuclear power plant enclosure were set up, with cable tray systems representing the two redundant trains located a horizontal distance of 20 ft apart. In

some of the tests1 in which one of the redundant trains (a vertical cable tray)

was set on fire, the second train suffered electrical failures occurring at

varying times from the inception of fire. IEEE Std. 383-qualified cables fared

better than their unqualified counterparts, and expectedly, fire retardant

coatings and ceramic fiber blankets on cable trays improved the chances of survival of both types. No suppression of the fire was attempted in order to ascertain the level of protection afforded by spatial separation alone without

benefit of the automatic suppression system.

The tests provided valuable insight into the fire growth process in a cable

tray and the nature of the consequential damage to a second cable system separated by an intervening space. They did not, however, provide the basis for extrapolation of the data to the numerous combinations of enclosure geometry and

equipment layouts that are encountered in nuclear power plants. It has also

since been realized that safe shutdown equipment other than cables may be vulnerable to fire. Obviously, some measure of protection is obtained by spatial

separation of the redundant trains. This protection, however, is effective for

a limited maximum severity of the exposure and for a limited duration. The

severity of the fire exposure in turn is dependent not only on its own characteristics, such as the heat evolution rate, but also on factors such as fire enclosure geometry, equipment layout, door and vent locations, fire locations, and

ventilation rate. Therefore, the NRC has not been able to clearly confirm the

adequacy of the 20-ft separation option. However, based on experience to date,

the question may best be addressed by studying the various factors affecting the

continued operability of equipment exposed to fire. These factors are:
-2-

1) the characteristics of the fire (energy and mass release rates),

2) the environment produced by the fire (temperature, heat flux, species

concentrations), and

3) the response of the equipment itself to the environment (fire damage

thresholds).

The overall fire protection research program being conducted by NRC, which is

discussed in more detail below is, therefore, to investigate these factors

separately and to combine the acquired knowledge at a later stage to address the

totality of the problem.

Additional specific needs are also addressed within the overall framework

of the fire protection research program. Among these are: 1) enhancing fire

test programs, and 2) addressing PRA fire-related issues. The above issues constitute a more thorough view of the overall objectives of the fire protection

research program.

Full-scale fire test programs represent necessary yet expensive means for

determining enclosure fire environments. Case-specific fire tests represent

prohibitive costs to both the NRC and licensees. Careful fire environment characterization and consequent modeling capability produced by this program can aid

in the careful selection of full-scale test cases and reduce the number of tests

required, thereby lowering costs.

Probabilistic studies (PRA) of nuclear power plants require data regarding

the occurrence frequencies and consequences of events which take place within

plant environs. Also, more detailed fire models can be used to benchmark models

used in fire-risk analysis thereby providing some measures of modeling and data

uncertainties inherent in these simpler models. An example of an event of

interest would be a fire within a safety-related NPP area. Data regarding the

consequential outcome of a fire in a specific plant area would likely not be

readily available. The effects of fire on safety-related equipment within the

NPP characterized by the fire protection research program would provide data to

the PRA analysis.

B. STUDY OBJECTIVES

NRC's Fire Protection Research Program (FPRP) is a multiphase, multiyear

research program requiring close coordination between the fire-modeling effort

being conducted at BNL and the continuing experimental program being undertaken

at Sandia National Laboratories. The goal of the FPRP is to develop test data

and analytical capabilities to support the evaluation of: (1) the contribution

of fires to the overall risk from nuclear power plants, (2) the effects of fires

on control room equipment and operations, and (3) the effects of actuation of

fire suppression systems on safety equipment. These three goals will be met by

(a) defining fire sources with respect to their energy and mass release rates,

(b) determining the environment resulting from the fire, and (c) determining the

response of certain safe shutdown equipment and components to the environmental

conditions.
-3-

As a subset to this overall objective, this report summarizes the work conducted by Brookhaven National Laboratory (BNL) to utilize, enhance, and develop

a computational capability for determining the environments within plant enclosures caused by fires and to initiate a probabilistic fire model/fire data base

to support fire-risk activities and projects within the NRC.

In this regard, this report essentially provides, in Section 1I, a detailed

description of the various elements and basics of the FPRP that have been conducted at BNL. This section also illustrates the coordination efforts between

the two laboratories. In Section I11, the results of these fire-modeling efforts are presented. Where this program is currently directed and what further

fire protection issues remain for analysis are discussed in Section IV. More

specifically, this report provides the following:

1. A survey of actual fire loads and configurations within nuclear power

plants (NPPs) and a classification scheme into several generic enclosure configurations. The purpose of this effogt and the results, detailed more fully in Section II-A, is to assist in the development of

a cost-effective enclosure fire-test program.

2. A process for selecting an existing fluid dynamic model/code which can

be utilized to investigate the thermal environment within complex NPP

enclosures resulting from prespecified initiating fires. The results

of this selection process are described in Sections IL-C, IIl-B-I, and

III-B-2.

3. A demonstration that, by experimental comparison, the selected model/

code has the potential for addressing the fire-protection issues previously described. Results of the efforts devoted to this demonstration phase are provided in Sections II-C and III-B-2.

4. A description of BNL's involvement in the development of an enclosure

fire test program structured to conform to the generic enclosure survey delineated above. Further details summarizing this effort are

given in Sections II-C and III-B-3.

5. A parametric study of the thermal environment within a plant-specific

control room resulting from a series of control cabinet fires. The

results of this phase of the study are detailed in Section III-C.

6. An example of the use of the code in an existing nuclear plant. In

Section III-D, results are shown in which the selected code was used

to analyze the spatial and temporal variations in a plant-specific

containment building resulting from a fire in one of its reactor coolant pump bays.

7. A discussion in Section IV concerning where effort in this program is

currently proceeding.
-4-

II. FIRE PROTECTION PROJECT DESCRIPTION

Within the four sub-program areas, outlined in the NRC Program Plan, there

is a division of effort between BNL and SNL which is essentially along the lines

of modeling and experiment. The remainder of this report addresses the BNL contributions to the overall FPRP which are essentially the modeling and code

development efforts. A summary of the BNL contributions within each subprogram

is outlined below.

A. FIRE SOURCE CHARACTERIZATION (FSC)

Survey of Actual Fire Loads and Configurations in NPPs. A survey of a number of nuclear power plants has been performed and a tabulation made fire-area

wise of in situ and transient fire loads. The geometry of the fire area, classification as to room type (vault, corridor, or bay), ventilation conditions,

and equipment type and location were also noted. The survey was restricted to

fire areas where threats to safety-related equipment may originate. Plant fire

hazard analyses, licensee submissions for exemption from Appendix R requirements, PSARs, and FSARs were the sole sources of this survey.

Survey of Existing Research Results. The mass and energy release rate

characteristics of probable source fuels such as flammable liquids in pools and

cable bundles were assembled from the literature. This project has already been

detailed in previous letter reports to the NRC and is not discussed further

here.

Experiments to Augment Existing Data. Experiments have been planned to

fill gaps in the information. The fuel configurations in such experiments will

be well defined and the fire unrestricted by ventilation. The experiments will

cover a range of sizes (Btu content) for each fuel and configuration. A large

part of this effort is described below under the subject of test matrix

development.

Recommendations for Source Fires. Source fires are to be defined from the

envelopes of mass and energy rate curves and possibly species concentrations

also obtained from the above experiments and surveys. This project has already

been detailed in previous letter reports to the NRC from BNL and SNL and is not

discussed further here.

B. FIRE ENVIRONMENT DETERMINATION (FED)

Fire Environment Model and Computer Code Selection. This task involved a

survey of existing fire models and selection of one for development in order to

address the problem of determination of fire environments in nuclear power plant

enclosures with typical layouts of safety-related equipment. The model is to be

translated into a user-oriented computer code, capable of describing the environmental parameters (temperature, velocity, fire-induced species concentrations) in three dimensions as functions of time elapsed from fire inception.
-5-

Computer Code Selection/Development. The computer code, which is the

numerical counterpart of the fire environment model, was selected based upon the

following requirements:

1) The analysis/numerical code in its basic form has already been utilized in enclosure/fire plume studies.

2) The code has the capability to predict the spatial and temporal variation of those fire-induced physical parameters deemed necessary to appraise the vulnerability of safe shutdown equipment, e.g., temperature, smoke, toxic gases and unburned pyrolysis products.

3) The code has the capability to assess the effects of enclosure geometry complexity such as obstacles and openings to the movement of the

thermal energy flux, mass flux, and momentum flux fields.

4) The effects of forced ventilation and its attendant impact on the distribution of the thermal energy generated by the fire within the enclosure can be addressed by the code.

5) The code is able to treat several types of enclosure fires resulting

from the burning of liquid and solid combustibles.

6) The code has the flexibility to analyze fires resulting from the burning of complex solid fuel configurations.

7) Exposure fires at various locations within the enclosure (e.g., centrally located, against a wall or corner) are also within the realm of

the code's capability. The code is capable of mapping the threedimensional, fire induced thermal energy field.

8) The code is structured in a modular fashion so that other fire related

aspects such as detection, suppression, and barrier effectiveness can

be readily analyzed once the requisite additional analysis is

supplied.

9) Fluid flow is treated as three dimensional and elliptic, i.e., flow in

one part of the building can be affected by changes in conditions in

other parts as well as outside the building.

10) Transient analysis is to be performed for the entire duration of the

exposure fire burn (i.e., typically 30 minutes).

11) The flow rate, temperature, and composition of the plume gases, prescribed as boundary conditions, can change with time.

12) The afterburn of plume gases may be accounted for by using an equilibrium chemistry model. The practice of simple chemically reacting

systems will be adopted. In this manner, scrupulous details of local,

multiple step reactions will be avoided, and the calculated gas temperatures will be expected to err slightly on the conservative side.
-6-

13) Buoyancy effects are accounted for by having an appropriate gravity

force term in the momentum conservation equation.

14) Fluid is allowed to enter or exit through the openings (vents, etc.)

in the building, the magnitude and direction of the flow depending on

the local difference between the ambient and inside pressure, which

can and does change with time.

15) Internal solid objects such as interbay walls, columns, horizontal

working platforms, etc., are simulated by specifying infinitely large

flow resistances in the appropriate momentum equations. As a result,

the normal velocity components at solid surfaces will be zero.

After demonstrating that the code has the capability of complying with the

above requirements/criteria, the FPRP is structured for further code development. In conjunction, it will subsequently be used to compare with the "benchmark" tests (see following) so that reasonable confidence is gained in its predictions in new applications. The postulated fire conditions for the computer

simulation will be the source fires developed in the FSC Project. Prior to

direct comparison with results from the test program the code will be developed

independently of the FSC Project in the interim period, using characteristics of

known test fires as input. Two sets 1-2 of previously conducted cable fire tests

have been utilized in a series of preliminary benchmarking calculations. The

results of these preliminary comparisons are described below.

Benchmark Testing. The generic enclosure survey has produced information

on typical enclosure geometries and equipment layouts so as to define a number

of generic enclosure geometries and generic equipment configurations. These enclosures, and to some extent the equipment, are to be replicated in a series of

fire tests where the energy and the mass inputs will be controlled to reproduce

the postulated fire sources. The instrumentation is designed to monitor the

various thermodynamic variables throughout the enclosures. The tests have been

planned to cover a range of geometrical variables (length, width, and height

ratios) and a range of fire severities (Btu outputs), so that the totality of

the test results by itself permits a degree of confidence in extrapolation to

other realistic situations.

Code Validation and User Package Preparation. The fire environment computer code will be continuously refined by comparison with the benchmark tests until reasonable confidence is gained concerning the accuracy of its predictions.

A complete package will then be developed for the NRC comprising the necessary

software, including a full listing of the program statements, flow charts, and

user instructions.

Combustion Product Migration. With the addition of existing submodels, the

computer code will be extended further to compute room-to-room migration of

toxic combustion products, which may affect the operability of equipment not

within the enclosure containing the source fire. This capability will be useful

in evaluating designs/layouts for which fire dampers and I- or 3-hour fire barriers have been employed for fire protection but for which migration paths may

exist between fire areas.
-7-

C. CONTROL ROOM HABITABILITIY AND FIRE SAFETY STUDY (CR)

Control Room Fire Vulnerability. Control rooms are characterized by assemblies of complex instrumentation and control cables in a high density layout.

Adequate separation of the redundant trains of the safety-related equipment is

usually impractical in this situation. Fire protection in a control room situation must, therefore, rely on immediate detection and automatic suppression of

the fire, as well as on the installation of protective enclosures, thermal insulation, and barriers where practicable. The vulnerability of the equipment to

the fire, its products, and the suppressants becomes especially important. The

techniques of analysis by computer simulation developed in the FED Project will

be applied to control rooms to predict the environment in the event of various

postulated fires, whose characteristics have been developed by FSC. The environments, coupled with the fire failure thresholds (FFT) of the various safetyrelated equipment, would enable determination of safety margins. Consideration

will be given to the electrical systems aspects of control.room designs including employment of circuit breaking devices and the capability to control and

monitor shutdown activities from a remote control panel.

While some of the above projects represent future aims of the FPRP, a large

majority of the code development and the experimental planning projects have

been performed in this past fiscal year. Detailed descriptions of these projects and summaries of their results follow.
-8-

III. BNL PROJECT SUMMARIES

A. FIRE SOURCE CHARACTERIZATION PROGRAM

Survey of Actual Fire Loads and Configurations in Nuclear Power Plants. A

survey of enclosures (fire areas) in thirteen nuclear power plants was performed. The plants surveyed were either PWRs or BWRs. The overall purpose of

the survey was to identify the generic enclosure parameters present in NPPs

along with equipment types present in each enclosure. Combustible loadings were

also specified as part of the task. A total of 134 enclosures were tabulated

and are presented in Table 1. A key is also provided as an aid in understanding

the enclosure specifications.

Enclosures are classified according to three generic types: (1) vault

(Z:w:h = 2:2:1), (2) corridor (L:w:h = 4:1:1) and (3) bay (L:w:h = 1:1:3). In

the fire area survey 89 vaults and 34 corridors were found. The typical vault

enclosure had a £:w:h ratio of 3.5:2.2:1.0 with an average height of 20 ft. The

corridors had a Z:w:h ratio of 9.2:1.3:1.0 with an average height of 15 ft.

Also encountered in the geometry survey were 19 rooms with odd configurations,

i.e., L-shaped, C-shaped, T-shaped, etc.

Fuel loads in the range of 1-19 lb (combustible)/ft 2 and 1-50 kBtu/ft 2 were

found. The cable insulation loads were predominately in the ranges 14-18 lb/ft 2

and 35-50 kBtu/ft 2 . Oil, grease, cellulose and charcoal were the other significant combustibles located within the fire areas.

Ventilation was also surveyed as a part of the project. Natural ventilation was found throughout in the form of doors, hatches and access openings at

the fire area boundaries. Stairwells, elevators and pipe chases are also indicated in Table 1. Forced ventilation strengths and locations are also delineated where available. Typical ventilation rates in vault-type enclosures range

from 1-12 room changes/hr. Switchgear rooms are typically at the high end of

this range with from 10 to 12 room changes/hr.

Equipment types present in each fire area have been surveyed. Equipment

type has been categorized generically as (1) cables, (2) panels and cabinets,

and (3) motors, generators and pumps. Designations of safety related equipment

have also been recorded in order to determine the relative positions of redundant safety systems within a given fire area. Due to space limitations these

data are not depicted in Table 1.

The sources of this survey were fire hazard analyses, licensee submissions

for exemption from Appendix R requirements, and to a lesser extent, PSAR's and

FSAR's.
-9-

TABLE 1 KEY

ENCLOSURE CLASS

EQUIPMENT

FUEL LOAD

DOORS

ACCESS

V

C

B

Vault

Corridor

Bay

(L:W:H=2:2:1)

(L:W:Hm4:I:1)

(L:W:H=I:1:3)

P - Panels, Cabinets

G - Generators, Pumps

C - Cables

lb - (combustible)/sq. ft.

g - gallons

kB - thousand BTU

kBsf - thousand BTU/sq. ft.

lb - pounds of grease

C' - cellulose (lb/sq. ft.)

char - charcoal

NF - treated with flamemastic and not

considered flammable

x/yN - x-single/y-double North Wall

zE - z-single East Wall

eW - Elevator West Wall

N/y' - north wall/y ft wide

pc - pipe chase

d - down

u - up

STAIRWELLS

HATCHES n/y 'xz'

F

pc

C

VENTILATION thor

RATE AC

EX.

SP.

GEOMETRY x

y

z

C

L

I

X

T

A

- n hatches/y ft. x z ft.

- floor

- pipe chase

- ceiling

isand cubic feet/minute

- air conditioning

- exhaust

- supply

- L length/height

- W width/height

- H height in feet

- C-shaped room

- L-shaped room

- I-shaped room

- intersecting hallways

- T-shaped room

- triangular room
-10-

TABLE I KEY (Cont'd)

PLANT L

Z

PI

Pt.B

IP

P

PB

G

Ml

M2

St.L.1

TP

B

Limerick

Zion

Prairie Island

Point Beach

Indian Point 2

Palisades

Peach Bottom

GESSAR

Millstone I

Millstone 2

St. Lucie 1

Turkey Point

Brunswick

TYPE P - PWR

B - BWR

ROOM LOCATION C

R

A

T

G, DG

RW

F

I

SW

Control Building

Reactor Building

Auxiliary Building

Turbine Building

Diesel Generator Building

Rad Waste Building

Fan House

Intake Building

Service Water Intake Structure
WAIM"(ILR 1 2 3 4 5 6- 7- 8 9 10 II 12 13 14 li 16 17 i8 19 20 210 22 23 24 25 26

ENCLOSURE V V V V V V V V V V V V V V V V V V V V V V V C C

CLASS

EQUIIIF'VNT P p p P p p p p p p P C,P P PO PG GP G G G G G G G PC P

IFUEL LOAD

CAMLE 1.6 1.0 3.1 1.7 3.4 2.6 2.0 2.7 1.2 6.0 13.5 17.8 2.6 3.0 1.0 1.0 6.9 2.3 1.0 16.9 7.8 2.7 16.6 3.9

OIL 2 g 34 g 8 g 1425 g 9.0

IRAAS/41 SC.

0/1 I E IN 2 N 0/I N 2 N I N I I I N I N I I E" 3 N IE I N I N E•S 211 1 2 N 2 I I N 2w 0/I 0/I S 2 , S I S IS IS I tE 1 N I S I 5 3S 2E 3 N I 5 2 IS

3/1 N eW 0/I E 0/2 w I S I w eN 3/ow I E

ACCESS W/? S/8 E/I1' W N/8' PC E

5/8'

STAIRWELLS I I 5 3

i(API, tl S FAN 3 2 MANY

VENTS

VENTILATION 5 FANS

RAll 2.0 1.7 4.0 3.5 3.8 15. 10.8 8.0 3.0 3.6 11.0 16.0 4.8

vEIr I'ATIO11

IM IENTAT ItO

Ii..a

(;1(7t41 TVf

PLANr

T"ION

I(VA I I Oil

5.,

2.6

22

L

C

6.53

3.3

L

C

9.2

4.4

14

C

C

5.4

4.8

28

2.8

1.9

24

3 4.3 3.6 2 3.1 3.9 4 .6 3.2 4.6 9 3.8 4 2.9

2.8 2 3.8 1.4 1.2 1.6 3.0 3.4 2.7 45 2.6 1.6 1.8

12 24 19 19 16.5 17 16.5 14.5 II 19 19 16.5 22

5.4 13.3 1.8 4.1 5.4 5.6 3.6 3.9

4.8 7.3 1 .4 3.1 4.5 4 1:1 0.7

28 12 12 14 II 19 14 .34 C

L

1I

R

z I I z~ lip I~ PP Ip 1 IPYB IpIPt8 PIIIP'sI PIF IIPI IP1I P181 Ipf P P P I p I P I PP B L I Z I Z I L

8 p p a Z IP1

A I A I A I A I T I A I C I C

C IC IA IA IA IG R A IA IC A IA I C R

Table 1. Generic Enclosures Survey
ROLAM NtIMPER 27 28 29 30 31 32 33 35 1 36 37 38- 39' 40 41 42 43 44 46 47 48 49

4-4--I-I -- 4- .4-4-I- -4-4.- ~~ P.- - - - - - -- + - A - I-4 -

WACLOSIMIlE

CLASS

EQU IPMENT

FUEL LOAD

LADLE

OIL

TfA! S/ MI SC.

DOORS

AC:ECSS

STAIRWELLS

IIATCFICS

C C C C C Y C V C C C C C C C C C V V V V V C

P*1 P P.GC PG PG G G,P P C.P CP C C C C C C C P,C PC P,G,C PC

8-2,' -l.0 6.) .21Bsf 4.5 6.6 1.5 10.1 9.1 42 0.7 5.9 NA Il8kBst 3 2

kýsA 52k0s0 11,3kBst 31.OkBst

I 0.4 14. 9k8$

.2 .9kBs .8 0.1 76kg 76k8 76k1 I.8kBst

I N N 0/ E/ E /N4 /0°' 3E 6E 26E WE 6E 2N N 0/46 IS

2 N 4 E 4 2 1E / N I S 0/ S0/ I 3 w 2 lW Iw I S 4S I Nw

I4 IS /IS IS I/* E

S/A' N/A' 2/1' S-2/101 S/4' N/4' 2/10' 2/8' E/PC S/9.51. N/ NE/3• N/3'

S/8' S/4' 10' Partlal

W/60'

2 2 2 Id 2d 2d 2 4

lu I'.

9 2/2'x2'

VFNTI LAT I01, FAN 3 FANS SMOKE

kATE 8.5 0.7 20. 8.5 7.0 54. 2.0 2.0 21.0 54.0 EXHAUST

VENT I LATION IE N I4E

ORIENTATION IS IN-4'

GEGM/TRY 4.5 I14.3 5.7 6.7 6.7 7.1 7.1 6.3 4.9 8.3 8.8 6.5 17.9 9.4 16.2 6.8 18 6.9 5.7 19.4 2.1 6.3 10.1

0.9 2.4 1 1 1.7 1.8 4.1 1.3 4.6 1.7 0.6 1.7 0.9 0.3 3.8 1 1 5.7 4.I 1.9 2.1 5.0 4.0

10 19 L 16.5 16.5 15 15 18.5 16.5 L 14 t8 45 17.5 14 14 11 40 8 L1 9.5 9.5 16 L 46 16 26 C

PLANT P Pl Pta IP IP PtB Pt" IP PB G G P8 PB Z IP IP M1 M M1 IP MI MI

TYlE P P P P P P P P 8 B B 0 B P P P P p B BT B 8 8

PYI A A A C C A A A RW A A T T A A C F T T T T T R

LOCAI I(IN

Table 1. Generic Enclosures Survey
RO.9 N*9IIER 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67

ENCLOSURE v V v V V V C V V V C C V V V V C V

CLASS

EQUIPMENT G.C CPG CG.P C.GP G.CP PC PC C GC PC P,C PC P,C C.P P.C PC GC

FUEL LOAD

CABLE 4.SkBSf 2.5k6st 2.2kBsf 26.,SkBsf 7.7kBsf 40.2kBSf 33.9kBsf NA 47.6kBsf 10.3kBsf 34.2kBst 9.7kBsf NF NF NF NF F -

OIL 0.5kB$ f 1.9kBs 64 g

TRANS/MISC. O.SkBsf O.71sf 3.SkBsf 1.3kBst 20 9 5.0kBsf 1.91,10

I N 2/ E N I E I N 2 E 0/I N 0/1 N IN I1 IN IW IN II IE IN IN

DOORS 2 W 0/I E IN I W I E I W W I , E/12.12 IE Is , IS /E

I6 6E 0/1 E 1/2 S 0/I S I S ROLL-UP IW 1W

ACCESS N.S/3$ 2N/3' E/6. S/41 N/18x20 W/4x7 E/6x7 E/Ix3

S/61 S/18x20 W/12x12 W/16xlO

STAIRWELLS 2 I 2 I I I I

HATCHES 1/20x20 1/20x20 2 PC 1/20x20 1/14xO F/IOxIO

VENTILATION 61.9 9.3 OUTSD 3 FANS INDEP. INDER. INDEP. AC AC AC/FAN AC AC RATE 2.0 AC 30.0 RECIRC. RECIRC. RECIRC. 45.2 25.4 17.0 19.0 4.0

RECIRC.

VENTILAI ION W/54- CEILING EX-FLOOlP IN-WALL W/51 W/IOxIO C/3x3 IN

nRIENTATIO(Y EXHAUST EX-CEIL. FAN E/5,x2. S/,5x.67 3W

W/204

CF(IME rRY 1.5 9.1 6.0 3.3 6.8 6.1 6.4 13.8 4.1 4.1 10.9 11.9 5.5 4.1 4.0 3.5 6.1 3.0

0.9 4 2.5 56 3.3 4.3 2.2 1.0 5.9 3.3 3 1.6 1.6 3.2 3.2 1.4 3.0 1.1 2.4

26 16 24 22 22 10 20 1 10 -20 '20 I 12 17 17 18 IS 17 I8

PLANT MI HI Mt mI HI 2 M2 42 M2 1M2 M2 M2 St.LI St.LI St.LI St.LI St.LI St.LI TYPE 6 8 a 6 6 P P P P P P P P P P P P P

6)04 R R R R R A A A I T T T A A A A A A

LoI ATIO l N 

IU3

Table 1. Generic Enclosures Survey
60. 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85

FI'CLOSITPlI V V V V V V V V C C C C C,B V V V V

CLASS

FUIIN[ -T N C C C,C PC GC GC G,C G CP C,G CG C,G C G,C CG CG C GC

FUEL LOAD

CAPLE NF fif NF NF NF NF NF NF NF NF NF NF NF NF NF NF NF

OIL >0. 12.0WDs >" >0 >0

TRlANS/'AISC. 4.4kNsf 7.Oks f 4.OkBsf 4.41899 0.168sf -- 3.k Bf 5.6kBsf 5.41k68 6.1k8sf 7.4k01s 2.2,85f

IE IE is IN 3W IE 1W IE IN

C(U,'•S 1. IW I W 2S 2S l/IW

2E 0/IE

AC!ýE S C/8l10 S/191 S/3' S/I10 S/41 E/4' S/5x6 5/4x6 3N/4x6 S/5x6 E/7x6

w/2A(I/2 S/21(1/2 E/13(1/2 8/5x6 W/5x6 N-S HALL E/16x22 S/12x6

WALL) WALL) WALL) OPEN W/16x22

STA 14II IS 3 I I I

iNT ILATI O' A, IC FAN AC AC AC FAN EX. FAN AC N/A N/A N/A FAN FAN FAN FAN FAN N/A

RAT, 1.1 0.9 5.0 0.7 2.0 2.1 0.4 6.0 2.5 1.0 1.0 0.2 0.2 1.0

VC'ETILATION SFW C/Ix3 W/3 N/EXSxI.5

PIIFINTATIC0, DUCTS E/SP.Ix2

,;F(VETF" 2.1 1.7 S.T 1.8 1.9 2.9 2.1 1.1 5.9 7.5 7.5 2.9 47.2 1.0 1.1 1.1 2.4 5.6

1.1 .1 1.3 1.7 1.4 2.4 2.0 0.7 3.0 0.5 0.9 0.5 2.4 0.3 0.6 0.6 1.6 1.9

is 19.5 1)95 22 20 17 20 17.5 11.5 11.5 L 11.5 C 13.5 L 6. X 36.5 21 21 14.5 16

PLANT S.I St.LI StLI St St tLI SL.1I StLI St.L1 TP TP TP TP TF TP TF TP TP TP

TYPE F P P P P P F P F F P P P P P P P

RO(1 A AA A A A A A A A A A A A A A

LOCAT I ON

I

Table 1. Generic Enclosures Survey
ROOM NUMOER 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103

EtJLOSUfRE C V V V V C C V V V V V V C C V V V

CLASS

EQUIPMENT C.P GP G PC GC G G,C G,C PC PC PC PC P,C PC GPC C,P G,P C,G

FUEL LOAD

CABLE NF NF NF NF NF NF NF NF NF NF NF NF NF NF NF NF NF NF

OIL >0 241b. 14Og >0 >0 >0 >0 320g 28g & 301b SIb

TRANS/MISC. 12.3kBSt 10 4.BkBsf >0 >0

N,E.S.W IN IE IE INN IN is IS 2N IN 2NE O/Iw

DOORS NUMEROUS 2W ISW O/IS 0/IN IE O/IE 2SE

0I/I 0/IE 0/ISW INW

ACCESS N/2.507 W/50x20 N/38x18 F/pc N/S

S17-1/2

x22

STAIRWELLS 2 2 I1

HATCHES

VEII7LATIOPI FAN N/A N/A AC N/A FAN 2 FANS 2 FANS FAN SP/EX SP/EX SPIEX SP/EX 3 FANS 4 FANS f NONE RB VENT

RATE 26.4 8.3 1.3 2.3 20.0 12.3 11.1 11.1 4.4 4.4 91.4 EA 91.4 8.2 3.0

VENTILATIOtN 2E/4x4 EX/NW EX/SW EX/NW EX/SW EX8/W/4.4 EXS/W/4x4 EX/Nw

lI ENINArIOt 4x4 404 SP/SE SP/2/NE SPS/E/4X4 SP/NS/

16/12

GEOMETRY 26.1 2.8 1.3 4.7 2.1 2.4 6.7 5.3 8.8 1.4 1.7 2.6 2.6 7.1 10.4 0.8 1a 7 3.9

1.0 2.2 0.5 3.5 1.9 0.5 1.5 1. 1 3*3 1.1 1.1 1.3 1.3 0.5 1.7 0.6 I*3 3.1

II T 22.5 24 14.5 18 19 15 19 20 26.5 26.5 17 17 17 17 17 34.5 13

PLANT TP TP TP TP TP TP 8 8 8 B B B a 0 B B 8 8

TYPE P P P P P P 8 8 a 8 8 8 8 a 8 B B 8

P.YIM A T T C R R SW SW DO DG DOG D DO DG DG DG R R

1.(0ATIONG

I

Lii1

Table 1. Generic Enclosures Survey
RACM NUMI'ER 104 10M 106 107 108 109 1O 111 112 It3 114 115 11 t17 lie 119 120 121

ENCLOSUIIE V V V V V V V V V V V V V C V 8,V C,8 C.B

(A ASS

/UI•YELNT GC G,P G,F C,PG G G GC GC P.C GtP C P,G C GP.C CG C C C

FUEL LOAD

CASLE NF NF NP NF NF NF NF NF NF NF NF NF NF NF NF NF NF NW

OIL 155.4&251b 28 9 &41b 30g&3¢b 31b 601b 451b 211b 51b 61b 30q 301b 40g&1121b 451b

MANS'MISC. CHAR,1201b

IE IW INE is IN eEW IS 18 IE 1W I5

DOORS ISE IN 1E lB IN IE

eNE

ACCESS E/28' E/25' PLUGS N/S EIW S/30- N/301 N/S/40'

W W

STAVI',. LLS I 1 I 1 I I I 4

HATCIES 1NF WALLS WALLS NE/20-20

IS CEILING CEILING

VENTILATION SP/EX SP/EX 10.5 EX 14.4EXISP N/A Avg. N/A N/A N/A

PATE 2.0 2.5 5.5 1.5 7.5 3.0 SPI.0&9.5 3.0 8.2 1.0 2.5 2.0 12.0

VENTILATION YP/ SP/Sx4 SP/S& SP/N&

ORIENTATION FLOOR FLOOR FLOOR

GEOMETRY 2.6 1.3 1.6 1.8 1.1 2.2 1.4 1.4 1.7 2.5 2.1 1.6 2.9 11.4 2.1 0.4 1.4 1.2

2.1 1.3 2.4 1.6 1.0 2.0 0.7 0.7 1.2 1.5 0.8 1.0 2.9 1.6 1.7 0.4 0.4 0.4

19 34.5 6 29 L 29 L 29 14.5 28.5 29 29 29.5 29 L 29 L 13 29 C 24 25.5 25.5 25.5

PLANT B 8 B B O B B a 8 B B B 0 a B B B

TYPE B B B B B B B B B B B a B B B B

A R RNRNRR R RIN R R R R C C C

LIC•Al OI

0"I

Table 1. Generic Enclosures Survey
ROOM N•LW8ER 122 123 124 125 126 127 128 129 130 131 132 133 134

ENCILOSURE 8,V BV. C,B Cs Vs w V V'B V V CB V V

CLASS

EQUIPM?4ENT C C C C C C C G,C C P.C C PC GC

FUEL LOAD

CABLE NV NF NF NF NF NF NF NM NV NF NV NF NF

OIL 28g6411b

TRANS/MISC. 5.0 C' 20 lb C'

IN IW IS IN IE 0/1E IE IE IS O/IE IE IN IS

DOORS IE IE 1W 1E

7/3W

ACCESS

STAIRWELLS 1

HATCHES

VENTILATIOII N/A N/A N/A N/A N/A N/A AC N/A SP/EX

RATE 0.6 0.7 0.6 0.4 34.2 2.5

VENTILATION NE/SE NE/SE HIE E SP/

ORIENTATION STAIRS

•EOMETRY 0.5 0.6 2.0 lI' 0.7 1.2 0.8 0.4 3.4 1.8 0.9 11.6 1.3

0.4 0.5 0.5 0.5 0.0 0.8 0.8 0.4 1.7 0.8 0.2 2.0 1.3

25.5 19 19 19 19 20 20 L1 20 9.5 19 19 L 19 34.5A

PLANT a B a B B B B B B B B B B

TYPE B B B B B B B B B B B B B

ROOM4 C C C C C C C C C C C C R

LOCATION

ITable 1. Generic Enclosures Survey
-18-

Survey of Existing Research Results. BNL has assisted in the compilation

of mass and energy release characteristics of probable source fuels encountered

in critical fire areas. Typical fuels identified were cable insulation, lubricating oil and grease, fuel oil along with more well-categorized combustibles

such as cellulose. Typical loadings of these combustibles are given in Table 1.

Experiments to Augment Existing Data. These preliminary experiments are

the responsibility of SNL. BNL has provided consultation and input (Table 1) to

aid in the selection of candidate source combustibles for testing.

B. FIRE ENVIRONMENT DETERMINATION PROGRAM

Fire Environment Model and Computer Code Selection. This project involved

two basic phases: (1) the determination of features required in the fire environment model and (2) the selection of a computer code which best fulfilled the

requirements set forth in the model.

The first phase of this project is best typified as a set of criteria which

any candidate model must meet:

(1) The analysis/numerical code must have already been utilized in realistic enclosures similar to what may exist in NPPs.

(2) The code should already have the capability to predict the spatial and

temporal variation of those fire-induced parameters deemed necessary

to appraise the vulnerability of NPP safe-shutdown equipment.

(3) The code should already have the capability to assess the effects of

NPP enclosure geometry complexity, such as obstacles and openings, on

the movement of the fire-induced thermal energy flux, mass flux, and

momentum flux field.

(4) The effects of forced ventilation and its attendant impact on the redistribution of the flux field must also be an aspect that the code

can address.

(5) The code must have the flexibility for analyzing fires resulting from

the burning of complex solid fuel configurations.

(6) Exposure fires initiated at various locations within the enclosure

(e.g., centrally located or against a wall or corner) must be within

the realm of the code's capability. Thus mapping of the three-dimensional, fire-induced thermal energy field is mandatory.

(7) The fire-induced flow should be treated as three dimensional and

elliptic, i.e., flow in one part of the building can be affected by

changes in conditions in other parts, as well as conditions outside

the building.

(8) Subsequent combustion of pyrolzate products may be addressed with the

unit-models employed in the code.
-19-

(9) Restrictive constraints imposed by the Boussinesq approximation should

not be included.

(10) The boundary conditions and field-grid structure inherent in the code

should be such that the effects of internal solid objects, such as

interbay walls, columns, horizontal working platforms, etc., on the

flow field can be readily investigated.

Given the above set of criteria, five potential codes/sources were reviewed as

candidates for selection: PHOENICS/CHAM, UNDSAFEII/UND, DRAGON/EPM, (Unnamed)/

NBS, and COBRA/EPRI.

A matrix (Figure 1) comparing the various attributes of each of the numerical codes was prepared to aid in the second phase of this project, viz., code

selection.

1 2 3 4 5 6 7 8 9 10

PHOENICS/CHAM * * * * * * * * * *

UNDSAFEII/UND * * *

DRAGON/EPM * * * *

(Unnamed)/NBS * * *

COBRA/EPRI * * *

Figure 1. Code Comparison Matrix

The CHAM-developed fluid flow analysis code PHOENICS was selected as the

model to be further developed.

CHAM of North America, Inc., specializes in the development and application

of mathematical models of fluid flow, heat transfer, and chemical reaction processes. Its primary business is to provide technical services, computer software and support in the field of fluid flow simulation. Adaptations of the numerical model utilized in PHOENICS 3 have been previously applied to fire hazard

analysis within the complex geometrical enclosures of NASA's vehicle assembly

building (VAB). The aim here was to determine the thermal environment in the

VAB following accidental ignition of solid rocket motor(s). An additional firerelated study was performed by CHAM's sister organization in the United Kingdom:

CHAM, Ltd. This study5 involved simulation of fire tests conducted to address

questions of smoke movement in shopping mall corridors. The following conclusions were drawn regarding the application of the model in the two cases:
-20-

(1) All results were qualitatively plausible.

(2) Calculated temperatures and velocities were in fair agreement with

measured data, where applicable.

(3) These applications, though demonstrating the potential usefulness of

the model/code, were not typical of cable insulation fires in NPP

enclosures.

Computer Code Demonstration/Development. Included within the framework of

this project was the preliminary validation of the computer code, PHOENICS, via

comparison with fire test results conducted with NPP environs in mind. Prior to

these test comparisons a summary of the numerical model is presented.

For purposes of the following analysis, a field model based on the solution

of governing partial-differential conservation equations of mass, momentum, and

energy is used. Gas flow is treated as three-dimensional, transient, and elliptic. The fluid is assumed to be a perfect gas with constant physical properties

pertinent to that of air. Density is calculated as a function of local temperature. Buoyancy effects are accounted for by using local densities in all terms

of the conservation equations, i.e., the Boussinesq approximation is not used.

The turbulence effects are accounted for by using the two-e uation k-e model

of turbulence,6 with known refinements for buoyant flows. Cable tray assemblies are simulated as combinations of perforated plates and blocks. The porosities of these plates and blocks are determined from the available information

on packing of cables. Thus, the presence of a cable tray disrupts the flow.

Heat transfer to and from the redundant (target) cable trays is neglected. The

calculation domain includes the whole room and some volume outside the door so

as to account for the effects of the canopy over the door and to avoid the need

of prescribing boundary conditions at the doorway. The fire heat source and

wall heat losses are prescribed as functions of time. Further specific details

of boundary conditions are presented later along with the discretization

details.

The independent variables are three coordinates (x,y,z) of a cartesian

coordinate system and time, t. Dependent variables include the three velocity

components (u,v,w), the pressure (p), the enthalpy (h), the turbulence kinetic

energy (k), and its dissipation rate (W). The conservation equations are expressed in the following general time averaged form:

at (pý) + div (p4 + J•) =S, (1)

where * stands for a general conserved property (u,v,w,h,k, etc.) and p, u,÷

4, S* are density, velocity vector, diffusive flux vector, and source term

for ý per unit volume, respectively. The diffusive flux, J,, is given by:

J =-r eff, grad , (2)

where reff,* is the effective exchange coefficient for the transport of property *. The values of reff and S for different ý's are listed in Table 2.
-21-

Exci

TABLE 2

hange Coefficients (ry) and Source Terms (SO) for Different 0 Variables

r s

1 0 0 (Continuity)

U l

1 eff -ax + 'P ax e a u + e v (eff ax) 3•y (eff ý-xC )

+ .(el

8z ('eff ix')

V Ileff ap + 3 P u + l- e v

ay ax eff ay) 3 eff 3y)

8z (eff ay)

w lf p -B g BP u

W 1eff az - ref) +a(x eff iz)

ay c•eff -Z) + 3z Ieff T)

h "eff evil

q

k Tieff Gk -p + Gb

ak

C 1'eff k [(Gk + Gb) C1 - C2 Pe]

From the table:

j ef 0' 11 + •£(3 )

lt Me P pk/I (4)
-22-

G[u)2 2

Ck~l~t f2 [(h +V(w)]

2 + a2 2 2 (5)

2 2 2u + (av2 and

G t ap (6)

b P a

The buoyancy production term, Gb, represents the generation/suppression of

turbulence due to buoyancy. In stable stratification (fire enclosures), ap/az

is negative; hence Gb becomes a sink term, and the turbulent mixing is reduced. The turbulence model contains five empirical constants which are assigned the following standard values6:

C1 = 1.44

C2 = 1.92

CP = 0.09 , (7)

ak = 1.0 , and

oE = 1.3

The computational model consists of a finite difference solution of the set

of elliptic partial differential equations expressing the conservation of mass,

momentum, energy and other fluid variables in three dimensions. The code generates local predictions of temperature, velocity, species concentrations, and

pressure. These calculated values were then compared with the measured data

from two series of tests conducted to simulate cable fires in NPP enclosures to

provide a preliminary validation of the computer model.

The first set of tests 2 were cable insulation burning experiments conducted

by FMRC under the sponsorship of the EPRI. From this series of tests, a particular case was chosen for analysis: (designated as Test #2 in Reference 2).

This test was performed in the enclosure depicted in Figure 2. Forced ventilation was rated at 6 room changes per hour, and the cable tray array was placed

in the center of the room and was arranged parallel to the ventilation flow (N

to S in Figure 2). The exposure fire consisted of 4 gal of methanol in a 36 in.

diameter by 3 in. deep pool placed directly below the cable array. The total

pool fire heat release rate was 286 kW. The cable array consisted of both horizontal and vertical cables which were interconnected. The total burn time for

the test was to be 1200 s although sprinkler actuation occurred sometime prior

to this set experimental duration. Boundary conditions for velocities are

determined by the flow rates at the ventilation source(s). Initial conditions

for density and pressure are those of ambient air. In order to establish
-23-

W

-- 12.19 1 i

Open Web E

,// Steel Joists

i Branc Lines

iNear Cross Main

44 Exterior Framework.

Eflx-Riser 50 mm x 150mm Lumber W2' 6')

spaced 0.61 m on center with

2. 5 Sheetrock nailed to interior

ýbservation Iceii r..

DorWindows-L__

Dimensions in units of meters

Figure 2. Three-dimensional view of FMRC test structure.

initial conditions for other properties a "cold-flow" case is simulated with no

heat source present. Reported data utilized in the computational validation

were (1) total heat release rate vs. time (input to code) and (2) one ceiling

gas temperature vs. time (used to compare with code predictions).

Problem formulation began with the setting up of grid structure simulation

of the test enclosure. Due to symmetry within the room (at the plane of the

ventilation inlet and exhaust) only half of the room was considered as the calculation domain. A total of 3368 control cells were utilized in the xyz grid

structure. The load cell, supporting the methanol pan, was represented as a

solid block. Cable trays were represented as solid blocks and plates (perforated and/or impervious). The exposure fire was represented as a heat source

spread over a region of computational cells. The heat and mass sources released

gases having the same thermophysical properties as air (molecular weight of gas

and enthalpy/temperature relation similar to air). Gaseous fuel was released

with specific heat and heat of combustion values as stated in Reference 2.

Instantaneous chemical reactions (SCRS) were presumed. A total of seven cases

were modeled:

Case 1.1: Simulated fire test room with nominal heat release rate and ventilation rate, but without any cable trays. Calculated 3 time steps to give

solutions at t10, 20 and 60 s.
-24-

Case 1.2: Same as Case 1.1, but with cable trays. Calculations performed

up to t=180 s.

Case 1.3: Same as Case 1.2, but with zero porosity of the top two rows of

cable trays. Calculations up to t=180 s.

Case 1.4: Same as Case 1.3, but with refined simulation of fire source,

i.e., finite mass release considered with heat release. Also, heat source is

spread over smaller volume (both height and width are reduced). Calculations up

to t=180 s.

Case 1.5: All cable trays simulated as impervious plates and blocks. Instead of using heat release rate directly as input, it is assumed that gaseous

fuel was released with specific heat and heat of combustion values as reported

in Reference 2. Instantaneous reaction (SCRS) was assumed. The mass release

rate is determined as a function of the heat release rate and the heat of combustion. The region of mass release changes (increases) with time in accordance

with Reference 2. Total heat release rates were reduced to 85% to neglect the

radiative component since it should have no effect on gas temperature as determined by the code. Calculations performed up to t=240 s.

Case 1.6: Heat release rate determined from the following expression:

Q= min (QA (Qm + 1/2(QA-Qm)))

where QA is the measured heat release rate reported, and Qm is the heat release rate of methanol in the equilibrium burning state (286 kW).

Case 1.7: Heat release rate adjusted to take an approximate account of the

pyrolysis process. In Reference 2 it is indicated that there is a critical rate

of mass release (;n" ) below which no cable combustion takes place. By using the

cr

values of QA' Qm' m cr' H (the heat of combustion for the cable), and A (the surface area of the cable exposed to nominal heat fluxes), the following expressions are derived to estimate the heat release rate:

QA < Qm ; Q = QA

QA > Qm ; Q = Qm + b H

where mb represents the mass release rate of the cable which is in excess of

;-° A and, hence, combustible.

cr

Cases 1.6 and 1.7 were run subsequent to the other five cases. These two

cases were necessary because the code was overpredicting ceiling gas temperature

as a function of time utilizing the actual heat release rate as input. The improvement effected in Cases 1.6 and 1.7 produces temperatures much more nearly

approximating the measured data.
-25-

Output from the code is illustrated in Figures 3 and 4. Figure 3 depicts

the flow velocity field at various times during the test. Flow exhaust port and

load cell are depicted in the figure. The entrainment of cold air into the fire

plume is clearly shown. Figure 4 shows isotherm contours for 500C and 60*C at

t=240 s. into the fire. This figure illustrates quite well the formation of a

stratified layer within the test enclosure.

Calculated velocities and temperatures show plausible trends, i.e., consistent with inputs and assumptions, for all cases. For example:

a) larger velocities in the plume region,

b) zero velocities across impervious plates (trays),

c) a large recirculation region (eddy current) above the entrance of ventilation air,

d) small recirculation regions in the lower corners,

e) highest gas temperatures in the fire source area,

f) high gas temperatures in the plume,

g) temperatures near the ceiling are much higher than those near the

floor,

h) in the corners, near the ceiling, temperatures are lower than in the

central parts, and

i) exhaust gas temperature increases with time; average room temperature

is lower than the exhaust temperature.

Comparison of calculated and measured gas temperatures, near the ceiling and

directly above the fire course, reveals the following:

a) all cases show good agreement with experimental data up to t=60 s.

b) all cases predict higher gas temperatures at t>60 s. The experimental

data shows a slower rate of temperature rise during 60<t<200 s. No

such reduction is seen in the calculated temperatures. The discrepancy is quite large, but the refinements in heat release rate specification in cases 1.6 and 1.7 greatly reduce this difference.

The results of this first attempt at validation were encouraging. However,

doubts as to the physical interpretation of the measured heat release data led

to the need for a second set of validation analyses wherein the heat release

rate could be more clearly specified. A second series of fire tests, 1 conducted

to investigate the 20-foot separation criteria, provided the experimental data

for further validation comparisons. These tests were conducted by Underwriters

Laboratories in conjunction with SNL under the aegis of the NRC. Figure 5 shows

a schematic of the test enclosure. The enclosure was 14 ft wide, 25 ft long,
-26-

Li

-'it- S

'I

5'

*1%

'I'

5'"

' ..

"-.5--

- -

60 secs.

-S.---

*1* -q

- - - = -

- - - - - -

- - = - -

* - - - - /

* . . I

* - - 1 ' '. - ~ - -.---- -.----

* . - ,.----------- - - - -

*............- - - - -

* * - - - - -

- - - - -. -

* I I I ~ - -

120 secs.

-r

I

t~ '5-.. I -

- I.. -

- - -

- - -I

- -- I-

- - - / - - ,

-. - - /

- -. - I

- - -

- 'I, -

240 secs.

Figure 3. Velocity vector field through central vertical plane

during fire growth.
-27-

Figure 4. Isotherm contours (T=50*C, T=60°C) at 240 secs. into fire.
-28-

25' 25- NOTE: 8' fot Experiment2 DOOR WIDTH

4' for Experiment; 3 and Tests I and 2

21.5'.5'

in x 5' Pan (10 Gallons

t Heptan. for Experiments 2

and 3) 15 Gallons Hea-

[ t sane so, Tests I and 2)

Cannopy

2 Vertical Trays

12.5% Fill (43 Cables)

Tests 1-6 Only

PLAN

21.5' 2.5'4

Redundant IA~

Cable Trays 4' a 8

ELEVATION SIDE

Figure 5. Fire enclosure details: preliminary fire experiments

No. 2 and 3 and full-scale tests 1 and 2.

and 10 ft high, with a doorway in one of the 14 xl0 ft walls. Four preliminary

experiments and six tests were conducted. Measured data consisted of wall and

gas temperatures and heat fluxes at various locations. Vertical thermocouple

rakes were installed at predominately three locations: 4 ft, 20 ft, and 25 ft

from the wall near the source fire. Fuel mass and heat release rates were not

measured. Subsequently, in order to use the test data for the verification of

numerical models, heat release rates were calculated1 0 for four cases: Experiments 2 and 3 and Tests I and 2. In this present analysis all four cases have

been simulated numerically by using the calculated heat-release rates as prescribed input. The salient features of these four cases are described below.

In Experiment 2 the doorway was 8 x 8 ft while in the other three cases the

doorway width was 4 ft. Experiments 2 and 3 involved 10 gal heptane pool fires

with no other combustibles. The pool was rectangular (I x 5 ft) and was placed

along the wall opposite the doorway. Tests I and 2 each had a 5 gal heptane

pool fire with electrical cables as an additional combustible, all placed

against the wall opposite the door. The cables were placed in two vertical
-29-

trays, suspended above the heptane pool, each loaded with 43 10-ft lengths of

cable. (12.5% fill). This amount of cable was estimated to equal 5 gal of heptane in total heat release. Two horizontal cable trays (the redundant division)

were also located near the ceiling and 20 ft away from the fire source. In Test

1 all cables were unqualified and unprotected. In Test 2 the cables were qualified but remained unprotected.

Because of the geometrical symmetry of the problem considered, only half of

the room was simulated. As illustrated in Figure 6, a total of 950 control

cells, with 5, 19, and 10 cells in the x, y, and z directions, respectively,

were used for all four cases. The grid distributions are non-uniform in each

coordinate direction, permitting good resolution of the solution in the particular area of interest. No-slip boundary conditions are applied at all solid surfaces, while at the calculation-domain boundaries outside the room, free boundary or constant-pressure conditions are applied. Heat source variations with

time as determined in Reference 10 are shown in Figure 7. Figure 8 depicts heat

release and loss rates for Experiment 2. Similar data are available for other

cases. Figure 9 illustrates the manner in which heat release and heat losses

F Y Fuel Pon

[1 X

Al_

Ir

1 2 3 4 5 6 7 8

4"

20"

L 0 11 12 13

PLAN VIEW

14 15 16 17" 18 19

2(r

Redundant Cable Tray. Canopy

ELEVATION VIEW

Figure 6. Grid distributions, coordinate directions and thermocouple

positions (shown by "X").
-30-

Heat Release

Rate Ikw)

900

Heat Release

Rate (kwj

8C-3

700

600

500

400

300

200

100

0

600

S00

400

300

200

100

0

0 4 8 12 16 20

Time (Min)

0 4 8 12 16 20

Time (Min)

Figure 7. Total Heat Release Rates for

Experiments 2 and 3, and

Tests I and 2.

Figure 8. Heat Release Rates and

Losses for Experiment 2.

S I I -A I I I

NOTES.

(a) Unilorm Volumetric Heat Release Rate Over Shaded Region

(b) Linear (Increasing with Elevationi Heat Loss Over Shaded Region

Figure 9. Volumetric Heat Release and Heat Loss Distributions
-31-

were modelled across the enclosure volume. As noted in Case 1.4 of the previous

set of simulations, decreasing the size of the volume containing the heat source

has little or no effect on the accuracy of results while increasing computer

time. Likewise the effect of allowing the heat source to spread in a realistic

manner also has a negligible effect on the temperatures of concern (located

-20 ft. from the fire). While the fire was not permitted to spread, the heat

release rate did follow the temporal distribution calculated from the experimental datal0.

All computations reported have been performed with the aid of a general

purpose finite-difference flow analysis comyuter code, PHOENICS 3 . An implicit,

successive substitution algorithm, SIMPLEST 1, has been employed. SIMPLEST is a

modified form of the SIMPLE algorithm. In both cases, global and species continuity is satisfied through solution of a Poisson-type pressure correction

equation.

Computations for Experiments 2 and 3 were performed up to 960 s in nine

time steps with At=60 s for the first two time steps and At=120 s for the last

seven time steps. For full scale Tests 1 and 2, smaller time steps (At=60 s

versus At=120 s) were used since transient heat release rates were larger and

steeper than those of Experiments 2 and 3. All computations were performed on a

32-bit mini computer (Perkin Elmer 3251), which is about ten times slower than a

CDC-7600 or at least twenty times slower than a CRAY-I. For each time step 100

overall iterations (sweeps) were performed. All solutions were well converged,

i.e., residuals were reduced by at least two orders of magnitude, and all flow

variables settled within 1%. Computer time requirement was about thirty minutes

per time step on the mini computer.

Figure 10 illustrates predicted transient development of doorway velocity

and temperature profiles for Experiment 3. At t=960 s these profiles are well

developed. The fire strength at this time is 548 kW. In order to assess the

similarity of profiles, data from Steckler's NBS room fire experiments12 are

shown in Figure 11. The comparison of Figures 10 and 11 provides a qualitative

verification of the calculated profiles. Figure 12 shows the comparison of predicted temperature near the horizontal (redundant) trays with the data of Experiments 2 and 3. The agreement is most satisfactory. There is a measurable increase in temperature of the environment when the door width is decreased from 8

ft (Expt. 2) to 4 ft (Expt. 3). Figure 13 shows the comparison of predicted

temperature variations within the stratified hot layer as a function of distance

below the ceiling for Experiment 3 data. The stratified layer structure observed in Experiment 3 is well predicted by the present model. Comparisons between predictions and measurements of temperatures recorded at several vertical

locations, 4 ft and 20 ft from the fire source, are shown in Figures 14 and 15,

respectively. The agreement is quite good in Figure 15. Figure 14 illustrates

a combination of two effects: 1) thermocouples, which were not shielded from

flame radiation, indicated higher gas temperatures than actually present, and 2)

quantification approximations made in the calculation of the heat release rate

have their greatest effect close to the source fire.
-32-

Z(m)

2.54 2.5

2.01- 2.0 ý

Experiment 3

O 60s

A 120s

N 240s

X 480s

* 960s

1.51- 1.5k

1.0k

Time

I F

1.0 1- Time

0.5

0

0.5

0

Door Width 1.22m

Heat Release 548 kw

at 960 Seconds

Li- L~L~L~ I

-1 0 1 2 273 373 473 573

Velocity (mis)

DOORWAY VELOCITY PROFILES

Temperature (

0 K)

DOORWAY TEMPERATURE PROFILES

Figure 10. Calculated development of doorway

profiles for Experiment 3.

velocity and temperature

y(m) y (m)

2.0

1.5

1.0

0.5

2.0

1.5

1.0

0.5

0

* Measured

Predicted by

JASMINE

0 a I I I

-1 0 1 2 3

w (mIs)

300 350 400

T °

0K)

DOORWAY VELOCITY PROFILES CORNER TEMPERATURE PROFILES

Figure 11. Measured doorway profiles in Steckler's (NBS)

experiments.

Steady-State
-33-

PHOENICS Prediction

-d&Experiment 3

PHOENICS Prediction

-&r Experiment 3

Temperature (°C) -W-Experiment 2

500 r--rTemperature (OF)

T- t 932

400

300

200

100

0

752

572

398

212

Temperature (°C)

600 -- i

550

500

450

400

350

300

250

200 -

150

100

50

0

Temperature (OF)

- 1112

0) 1022

932

842

11. - 752

-662

2) _ 572

482

13f \ 392

*• 302

212

122

0

20 25

I t I 132

0 300 600 900 1200 1500 1800

Time (Seconds)

0 5 10 15

Time (Minutes)

Temperatures are the Average of Thermocouples

69.73 and 77.(1' Below Ceiling and Z from the Tray) 4" FROM SOURCE FIRE

Figure 12. Predicted and measured

temperatures for Experiments 2 and 3.

Figure 14. Predicted and measured

temperatures at several

levels for Experiment 3.

PHOENICS Prediction

Temperature (°C) -ArExperiment 3

Temperature (OC

400,

-)

PHOENICS Prediction

.*,.Experiment 3 Temperature (OF)

300

1' Bel

200

100

O

low Ceiling -

20' Below

C 'eiling 3'Below Ceiling

Measurements 3" CilinB o I I I

572

392

212

I *=

550

500

450

400

350

300

250

200

150

100

50

I i i

1' Below Ceiling (TC73) Measurer

m 27 Below Ceilin(

Temperature (OF)

r 1112

1022

932

ment 842

g (TC74) 752

- 662

-- 572

- 482

392

:761 Z, 302

. . 212

122

2 2. 0 20 25 0 300 600 900 12(

Time (Seconds)

00 1500 18]11 32

o0 0 5 10 15

Time (Minutes)

Thermocouples are 2' in Front of Horizontal Tray

Figure 13. Predicted and measured

temperatures at several

levels for Experiment 3.

20' FROM SOURCE FIRE

Figure 15. Predicted and measured

temperatures at several

levels for Experiment 3.
-34-

To illustrate the overall flow pattern, a calculated velocity field for

Experiment 2 at t=360 s is presented in Figure 16 in two longitudinal vertical

planes. Inspection of the velocity fields which are generated by the code reveals the following.

Exp. 2

ELEVATION; Near the Wall; IX=NX t=360s

LL2iLL -. ---.

S ELEVATION; Near the Center, IX=1

Figure 16. Velocity Distributions in Two Longitudinal

Vertical Planes (Experiment 2)

* Strong upf low motion, induced by the fire source, impinges on the

ceiling and is deflected outward along the ceiling.

* The hotter air is removed from the enclosure through the upper part of

the doorway.

* Cold air is drawn into the enclosure through the lower section of the

doorway. As expected, a recirculation eddy is observed between the

door and the side wall.

Full scale Tests 1 and 2 were similar to Experiment 3 in all respects except for the presence of vertical cables above the heptane pool. These cables

also burned, and as a result the heat release rates were higher and steeper than

those of Experiments 2 and 3 (Figure 7). Figures 17 through 22 show the comparisons of calculated and measured temperatures at various horizontal and vertical

locations. The difference between predicted gas temperature near the cable and

the measured temperature (the thermocouples were located on the cable skin)

shown in Figures 18 and 20 is plausible since it is is- due to the thermal inertia of the cables, which has not been included in the computational model. As
-35-

Temperature (°C) Temperature (OF)

- 1112

'rediction

rement - 932

752

572

- 392

5 212

32

1500 1800

Temperature {°F)

--- 1 1112

932

752

572

392

212

0 300 600 900 1200

Time (Seconds)

0 300 600 900 1200

Time (Seconds)

1500 1800

Temperatures are the Average of Thermocouples 69. 73 and 77 Temperatures are the Average of Thermocouples 69, 73 and 77

Figure 17. Predicted and measured

temperatures at I' below

ceiling and 2' from the

tray (Test 1)

Figure 19. Predicted and measured

temperatures at 1' below

ceiling and 2' from the

tray (Test 2)

Temperature (OC)

500 r-'-

Temperature (OF)

1 932

Temperature (°C)

500 -

Temperature (OF)

- 932

400

300

200

100

400

300

200

100

752

572

392

212

0 300 600 900 1200

Time (Seconds) ,

0 1500 1800 - M0

0 300 600 900 1200 1500 1800

Time (Seconds)

Figure 18. Predicted and measured

temperatures at redundant

target (Test 1).

Figure 20. Predicted and measured

temperatures at redundant

target (Test 2).
-36-

---- PHOENICS Prediction

-- Measurement

Temperature IOC)

1100

1000

900

Temperature (OF)

-2012

1832

1652

1472

1292

1112

0 5 10 15 20 25

Time (Minutes)

4" FROM FIRE SOURCE

Figure 21. Predicted and measured temperatures at several locations for Test I.

PHOENICS Prediction

Measurement

Temperature (°C)

1100

1000

900

800

700

600

400 -

300

200

1000

Temperature (OF)

2012

- 1832

1652

1472

1292

- 1112

F4)

- 932

(TC75) 1752

572

392

212 - 0 1

0 10 15

Time (Minutes)

20 25

20" FROM FIRE SOURCE

Figure 22. Predicted and measured temperatures at several locations for Test 1.
-37-

expected. the predicted temperature is higher during the fire development period

and lower thereafter. In general, the predicted temperatures conform to the

measured ones. Early in the burn the hot layer is seen to develop very rapidly

due to highly non-linear heat release from the cable burning (Figure 7). Near

the end of the tests the hot layer temperatures reduce significantly due to the

diminishing fire strength.

Graphical representations of selected isothermal surfaces for Experiment 3

and Test 1 are displayed in Figures 23 and 24. The progressive emergences of

hot stratified layers are clearly observed. These results show physically

plausible trends, e.g., early in the burn higher temperatures are developed in

Test 1 compared to Experiment 3. Similarly, near the end of the tests, a lower

temperature environment is observed for Test 1.

Exp. 3 Exp. 3 Exp. 3

t = 360s t = 360s t = 360s

T - 1000C T = 2000C T = 3000C

Exp. 3

t = 960s Exr,. 3 T =300°C

t = 960s

T = 1000C

z '

Figure 23. Stratified hot layer development for Experiment 3.
-38-

Test I Test I Test '

_t = 36Cs t = 3COS t = 36C3

T = IUU°C T = 3C0 T = 6C'ýC

Test I t NOS

t = 840s T

T = I00°C

Figure 24. Stratified hot layer development for Test 1.

Calculated flow fields and temperatures are physically plausible. Velocity

and temperature profiles across the doorway are similar to those reported by

Steckler 1 2 for similar tests. In most respects, agreement between the calculated and measured temperatures is excellent. Differences in agreement are due to

the effects of using unshielded temperature probes in areas dominated by radiative heat flux. The exercise has demonstrated the capability of this field model for prediction of the thermal environment within enclosures subjected to

pool/cable fires.

Benchmark Testing. The responsibility for the fire tests lies with Sandia

National Laboratory. BNL's contribution to this project consisted of assistance

in establishing test matrices for the two cases of benchmarking tests to be performed: (1) baseline validation tests and (2) cabinet/control room tests.

Additionally, BNL has provided input to aid in the selection of a test facility

wherein these validation tests will be performed.
-39-

BNL's primary contribution in this project has been via assistance in the

determination of the necessary physical properties for validation of the mathematical model described previously. Interactive meetings with both SNL and the

NRC have produced a set of requirements for test output data. The most prominent of these properties are temperature, heat release rate of the source fire,

convective and radiative heat fluxes, flow velocities at various locations and

combustion species concentrations at several locations. Given these required

properties, instrumentation needs for the test enclosure have been specified.

This process specified an important set of considerations to be utilized in the

selection of a test facility.

Test matrix development was also performed within the interactive meeting

framework outlined above. Once the required physical test output data had been

identified, decisions were reached regarding the number and type of tests needed

to specify the properties within the matrix parameter space consisting of geometry, flow conditions, source fire type and strength, and obstacle configurations

within the test enclosure. Both the physical matrix reqVirements and the time

factors generated by the matrix design represent prominent additional factors in

the test site selection process..

C. CONTROL ROOM HABITABILITY AND FIRE SAFETY STUDY PROGRAM

An additional application of the computational model recently initiated is

the study of the fire environment within the LaSalle NPP control room which is

being performed in conjunction with the PRA analysis of the RMIE project. Figure 25 presents an example of the computational cell model of the LaSalle control room. Objects, such as cabinets, control consoles, etc., are modelled as

solid blocks. The plan view shown is at floor level and depicts such items as

consoles, desks, chairs and other flow obstacles present at this level. The

complete conputational model consists of several (7) horizontal slices covering

I I I I I I I I I 1.8-I

I owns MORE 1

16- 1 SEE NnllllIEN 0 SORENSON NEun I

I MEEN Eon. 1

14- I NEON REEnENE NIENENEE mass I

I none sEEn I 12- niou Enon I

V 0-I I Ross EEN I1 m ENEEEEBN summEn U U KEEN Enos I Y 10-1 Bonn a monsoons 0 most

I EoEN U Eo gnomo on K OmUnE I

8- I EoEn BEnn sEml I

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6- 1 MilEN NENEENNE EEE**EEE*E*EE I

I BEUEsEEmEENEE oE *ENEEEENEIEEEB

4- EKEENEENEENmEE EEEEENEEEEEE I

I * lnN llEEENU nE En EDEEnEneElNEK i

2-I I E ENEKEEEEE EN EU EU

4I8 a a 12 me 28 32 I

4 8 12 16 20 24 28 32 36

X

Figure 25. Horizontal Cross-Section
-40-

the entire room height from floor to ceiling. The grid depicted in Figure 25 is

36x18, however, in the computational analysis the grid was modified slightly to

32x19 to produce a total of 4256 control cells within which the governing conservation equations and constituent relations (see Table 2) are numerically

solved.

Figure 26 depicts a detailed view of the cabinet structure within the valance frames of the control room. The LaSalle control room is unique in that

these two L-shaped areas are actually exhaust plenums for the ventilation system. The forced ventilation inlets are distributed throughout the control room

though there are none in the plenums. There are exhausts located in each plenum

near the corner of the "L" at ceiling level and one additional small exhaust located outside in the control room. Air is drawn into the plenums through vents

in the bottoms of cabinets and consoles which form part of the boundary of the

plenums. Steel valances extend from the tops of the boundary cabinets to the

control room ceiling thus isolating the exhaust plenums from the main portion of

the control room. In addition to the forced ventilation exhausts, there are

five doors leading out of the control room. Although these doors remain closed,

I I I I

1 8-

I ; I

16-

7--

14-

12-

a a

-1-, a a * I

-'--1 a a a I

* a

* a

-rna a

~~7~~~~ * a

10- ,-TF_

18- '

6- r-'' " "''"""

8- __ a : L .I . _.I . _J ..

4---11 II

,W. ._J

: --- -- ---

*

* a a I..l .l _l.l .l .l .l [_.. . -.. ll -. .

a a a

20 8 a 3

I I

4 8 IJ 1 &

Figure 26. Valance Horizontal View
-41-

there is a total exfiltration rate of 1500 CFM out of the control room through

these doorways. Total forced ventilation into the room is 24020 CFM. Room

dimensions are 60 ft x 120 ft x 16.5 ft high, yielding an approximate 12 room

changes per hour ventilation rate.

Two cases have been examined in the initial phases of this study: 1 3 (1)

steady-state cold flow with no source fire, and (2) 6 min realtime simulation of

a source fire located at (25,16) on Figure 25. The analyses of these two cases,

while preliminary in nature, illustrate the expected physical properties which

occur in enclosure fires.

The first of the above cases (cold-flow) was analyzed as a baseline case to

establish the flow patterns within the control room under nominal steady-state

state conditions. Flow is seen to proceed downward from the inlets in the cabinets and consoles at the plenum boundaries and up into the plenums and out the

ventilation exhausts. Additional flow components also exit the control room

through leakage from the five external doorways. Physically realistic flow patterns and velocities are observed at all obstacle boundaries.

In the second case above, a source fire modelled after the work of

Williamson et al.14 is utilized. This fire is not placed at a plenum boundary

so the environmental effects are entirely whole-room effects and do not substantially perturb plenum conditions thermally or otherwise. Figure 27 depicts the

flow conditions at floor level. For simplicity, flow obstacles such as cabinets, control consoles, etc., are not depicted in this figure as well as in

Figure 28. Entrainment into the plume is clearly shown as is air flow into the

exhaust plenums. Note that air flow through doorways is now into the control

room as additional cold air is drawn in due to the buoyant action of the fire

source. Figure 28 illustrates the thermal history of the environment at three

time steps following fire initiation. At t=6 mmn it should be noted that the

150%C isotherm has not descended below 10 ft at any room locations other an very

near the fire source, although some thermal mixing is observed even at floor

level due to the ventilation jet induction. A critical time in fire history may

be the time where the hot layer drops below the ventilation ducts and becomes

substantially mixed with cooler air below. This time represents a critical

stage in dispersion of toxic and thermal effects throughout the main body of the

control room.

The preliminary examination of these two cases once again illustrates the

physical applicability of the computational model. All of the primary characteristics of enclosure fires are present and modelled realistically. The usefulness of the model is demonstrated again via the thermal mapping and flow pattern analysis presented. Three-dimensional thermal and toxicity profiles are

readily constructed from code output, and effects on equipment and personnel may

be determined therefrom. However, until this phase of the study is completed no

conclusions will be drawn regarding control room habitability and equipment

damageability.
-42-

Fire Strength = 600 kw

JZ=J / 

t = 360 S

Maximum Velocity = 0.65 m/s

I Z=1

~s44. ~4 4 .

'4 .--

I--- -

' \ '

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.\ 1

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-I -

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* I ~ *I IPf

.' 4% ~ 4.

* -' 4 -

- I

'S -

- I

.4

4

' %.4S*S 4

.4

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-4

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4.44.4

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Figure 27. Velocity distributions in horizontal plane IZ=1 at t=360S

D. PLANT-SPECIFIC CODE APPLICATION

As part of the on-call assistance program BNL is called upon to review

licensee-submitted requests for exemptions to Appendix R of 1OCFR50. The thesis

is that a postulated, probable fire in one of the Reactor Coolant Pump (RCP)

bays would not affect the operation of redundant safe shutdown equipment. Fireinduced containment temperatures and pressures were calculated, through the

models employed, to stay within acceptable limits. The scope of our review entailed answers to the following questions:

Are the fire scenarios analyzed, albeit somewhat simplified, reflective of what may realistically occur? In other words, does the physical model employed represent an adequate replication of the major

fire-related phenomena?

" Concomitantly, does the mathematical model portray adequately these

major physical processes?

• Does the actual scenario analyzed bound the overall problem?

" Are the conclusions drawn from the calculated results valid, uniformly, with the assumptions made to provide a tractable analysis?
-43-

Fire strength = 600 kw

t = 120 S

T = 1500C

z

7

Figure 28. Development of temperature field at various times.
-44-

Our review of the fire models employed is through direct comparison of reported results using, in lieu of a quasi-steady, zone-model approach as employed

by the licensee, a more fluid-dynamically detailed, two-dimensional, transient

analysis. By definition and by solving a more accurate representation of the

transfer of mass, momentum, and energy through convection and diffusion, assurances are provided that, indeed, the mathematical/physical model employed (for

direct comparison of the numerical results) is a truer representation of the

fire scenario. The analysis attempts to model the vertical temperature profile

inside the containment building resulting from the combustion of 80 gal of lube

oil on the floor of an RCP bay. The licensee uses a one-dimensional fire plume

model coupled to a one-dimensional stratification model. This is supplemented

by a ventilation flow model for buoyancy driven flow through RCP bay openings

near the bay floor and ceiling. The objective of the analysis is to show that

hot combustion products do not enter neighboring bays because of a chimney effect and that temperatures and pressures in the containment building do not represent a hazard to safe shutdown equipment short-term operation.

The plume model is assumed to be steady-state. This is justified because

the plume response time is one or two orders of magnitude faster than the heatup response time of the containment as a whole. However, the stratified layer

model is dynamic in that the growth of the layer with time is simulated, starting at the top of the containment and moving downward. The one-dimensional

nature of the model ignores the effects of the lateral placement of the fire

within the containment and requires the model elements to be visualized as being

axisymmetric about the containment building centerline. Also, toroidial vortex

development within the stratified layer as a result of bouyancy induced forces

and vertical plume momentum transfers resulting from containment wall interaction, is not considered. Basically, the analytical modeling provided in the

submittal can be asociated with what is termed as the "classical filling-box"

model.

We used the PHOENICS code to simulate the 80 gal lube oil fire. The code

was run in two dimensions, axisymmetric about the containment building centerline, using the geometry given in Figure 29 on a computational grid of 10 by 15

cells. A constant heat flux of 7644 kW (convective heat release rate of the 12

ft diameter lube oil fire) was input at the center floor cell of the model RCP

bay for a total of 10 minutes, with the results printed each minute.

Using the simplified analysis, the temperatures in the containment were

computed to be 450K near the ceiling, 429K at 66 ft and 350K near the floor.

The PHOENICS results show a similar flow field with temperatures (interpolated

to 10.5 min) of 440K, 428K and 385K, respectively. The PHOENICS results therefore support the simplified analysis for this geometry.

The flow field vectors are shown in Figure 30. The vectors are plotted on

a two-dimensional cross section of the containment building and are magnified

seven times to aid visualization of the complete flow field. The flow out of

and into the RCP bay is clearly shown, as is the entrainment into the plume.

The return circulation causes the temperature near the containment base to be

hotter than that computed by the simpler analysis.
-45-

5 1.054m

I

I

MAIN

CONTAI NMENT

VOLUME

PENETRATION

ROOM

-2C. 12:n

I

14.63 m.

14.02 M

6.71 m

CEILING

VENT

RCP

BAY

OPERATING "i

FLOOR F_ _

COOLER

ELEVATION

I

BASE

0.00 m VENT

Figure 29. Containment model geometry.
-46-

i!s98

Figure 30. Flow vectors plotted on a 2-D cross section of the containment

building. The vectors are magnified seven times for details. The

plume updraft is 6 M/S, the downdraft is 5-10 cm/s, and the inflow

at the RCP bay base is I M/S. (Graffic: CHAM Copyright)
-47-

A comparison of the temperature profiles in the containment outside the

plume are shown in Figure 31. In Figure 32, we have plotted the isotherms in

the containment building at the end of the fire. The lines are contours from

386K to 450K in 2K increments and show the resulting stratification.

This comparative study has shown that PHOENICS can be used to benchmark

simplified analysis. By using a more fluid-dynamically detailed, twodimensional, transient analysis, we were able to closely produce the results of

the quasi-steady, zone-model approach employed and feel confident that the model

adequately portrays the major physical processes under the assumption of a simplified geometric portrayal of the containment building.
-48-

PHOENICS

411

0 4 ft. DIAMETER OF FIRE tburn =!410 S.

+ 4 ft DIAMETER OF FIRE tbum= 5 6 4 0 S.

A 12ft DLAMETER OF FIRE t1•rn =62eS.

380

~/

i370

360/

350

340 c

320 ---------- I

0 5 10 i5 20 25 30 35 40 45 50

ELEVATION FROM CONTAINMENT BASE (M)

Figure 31. Containment temperature profile at end of variously sized

lube oil fires.
-49-

1981I

Figure 32. Lines of constant temperature in the containment building

after the postulated fire. The contours range from 386K

to 450K in 2K increments.
-50-

IV. FUTURE DIRECTIONS - BNL

A. Validation with Cabinet/Control Room Test Data

This phase of the study awaits the output from the cabinet/control room

tests. These tests will enable the final set of validation simulation studies

within the program. Additionally, these tests will provide the basis of comparison for including a series of upgrades within the framework of the computational model. These upgrades include (1) modifications for chemical reactions, and

(2) modifications for heat losses to enclosure boundaries and objects within the

enclosure. Modifications for chemical reaction include provisions for the following: transport of toxic gases, chemical reaction with SCRS (Simple Chemical

Reaction System) model, and one-step, finite-rate reaction model. The second

and third portions of this task enable the elimination of the need to specify

heat release rate data as input to the code. Modifications for heat losses include the effects of both convective and radiative heat transfer. Radiative

heat losses will be calculated eventually by the incorporation of a six-flux

radiation model. These heat loss modifications will enable the detailed examination of heat flux effects on sensitive equipment located within the enclosure.

B. Parametric Study of Fires Within NPP Control Rooms

Of concern in both this study and also the RMIEP probabilistic survey is a

fully involved cabinet fire and its effects on adjacent and non-adjacent control

room systems. BNL and CHAM are to utilize the code described above to model

this control room scenario. The control room will be divided into a threedimensional grid as detailed above, and various source fire strengths and locations will be examined in the context of both deterministic and probabilistic

analyses. The effects of both the thermal environment and the toxic gas environment will be determined by utilizing the analytical techniques developed to

date in this project.
-51-

V. CONCLUSIONS

Primarily, this study has shown the following:

1. Existing field model fire codes, namely PHOENICS, are readily available to assist in appraising the effects of prespecified fires within

complex nuclear power plant enclosures under both normal and forced

ventilation conditions.

2. By direct comparison with enclosure fire experiments, reported herein

as well as in the open literature, the PHOENICS code and its solution

algorithm has been adequately demonstrated with regard to its capability of reasonably predicting spatial and temporal variations of fireinduced environments.

3. Suggestions made by PRA practitioners and PRA reviewers regarding the

wide uncertainty associated with fire risk analysis, indicate that the

modeling effort described in this report can be utilized to "benchmark" deterministic fire models/codes presently employed in analyzing

fire risk.

4. The ability of the code to map the thermal and toxic gas environment

within complex enclosures, given the energy release rate and toxic gas

mass source rate of the initiating fire, indicates that the output of

the code can be used to better scope enclosure fire experiments and

provide "boundary-condition information" for component fire vulnerability (fire fragility) test programs. Critical areas where enclosure

fire test instrumentation should be concentrated can be easily defined

through examination of these thermal maps.

Based upon these efforts and the findings reported herein, it is concluded

that not only are the future directions described in Section IV warranted and

doable, but the present state of the code has the requisite, built-in features

to address the fire-protection issues that have been identified and thus better

assure realistic, cost beneficial, and continuation of the Fire Protection

Reseach Program.
-52-

REFERENCES

1. Cline, D.D., Von Riesemann, W.A., and Chavez, J.M., "Investigation of

Twenty-Foot Separation Distance as a Fire Protection Method as Specified in

10CFR50, Appendix R," NUREG/CR-3192, SAND83-0306, October 1983.

2. Hill, J.P., "Fire Tests in Ventilated Rooms-Extinguishment of Fires in

Grouped Cable Trays," EPRI Project RP 1165-1-1, Report NP-2660, prepared by

Factory Mutual Research Corporation, Norwood, MA.

3. Spalding, D.B., "A General Computer Program for Fluid Flow, Heat Transfer

and Chemical Reaction Processes," presented at the International FEM-Congress, Baden-Baden, Germany, November 17-18, 1980.

4. Planning Research Corporation, "Solid Rocket Motor/Vehicle Assembly Building Inadvertent Ignition Effects Study," NASA KSC-DF-441, September 1981.

5. Cox, G., "A Field Model of Fire and its Application to Nuclear Containment

Problems," Proceedings of the CSNI Specialist Meeting on Interaction of

Fire and Explosion with Ventilation Systems in Nuclear Facilities,

LA-9911-C, Vol. I, p. 199, April 1983.

6. Launder, B.E., and Spalding, D.B., Mathematical Models of Turbulence, Academic Press, London, 1972.

7. Markatos, N.C., Malin, M.R., and Cox, G., Mathematical Modeling of

Buoyancy-Induced Smoke Flow in Enclosures," Int. J. Heat Mass Transfer,

Vol. 25, No. 1, pp. 63-75, 1982.

8. Markatos, N.C., and Cox, G., "Turbulent Buoyant Heat Transfer in Enclosures

Containing a Fire Source," Seventh International Heat Transfer Conference,

Munchen, 6, p. 373, 1982.

9. Bagnaro, M., Lauuisset, M., and Lockwood, F.C., "Field Model Prediction of

Some Room Fires: Steady and Transient," The 21st National Heat Transfer

Conference, pp. 107-114, Seattle, WA, July 1983.

10. Nowlen, S.P., "Heat Release Rates During the Sandia/UL 20 Foot Separation

Tests," Letter Report prepared for Electrical Engineering Branch, Division

of Engineering Technology, Office of Water Reactor Safety Research, U.S.

Nuclear Regulatory Commission, DOE 40-550-75, NRC FIN-AlOIO, June 1984.

11. Spalding, D.B., "Mathematical Modeling of Fluid Mechanics, Heat Transfer,

and Chemical Reaction Proceses," CFDU, Report No. HTS/80/1, 1980, A Lecture

Course, Imperial College.

12. Steckler, K.D., Quintiere, J.G., and Rinkinen, W.J., "Flow Induced by Fire

in a Compartment," NBSIR-82-250, National Bureau of Standards, 1982.
-53-

REFERENCES (Cont'd)

13. Singhal, A.K., and Tam, L.T., Progress Report: "Fire Modeling for Nuclear

Power Plant Enclosures - Three Dimensional Calculations," CHAM of North

America, Inc., Prepared for BNL, Feb. 1985.

14. Williamson, R.B., Mowrer, F.W., and Fisher, F.L., Final Report: "Fire

Safety of Electrical Cabinets," Lawrence Berkeley Laboratory, Prepared for

NRC, Jan. 1984.

NRC FORM 335 U.S. NUCLEAR REGULATORY COMMISSION I. REPORT NUMBER (Asspgnedbv TIDC. add V4 No. t a•,y)

12-841 NRCM 1102. NUREG/CR- 4479 3201.3202 BNL/NUREG- 51948

SEE INSTRUCTIONS ON THE REVERSE

2. TITLE AND SUBTITLE 3. LEAVE BLANK

THE USE OF A FIELD MODEL TO ASSESS FIRE BEHAVIOR IN COMPLE

NUCLEAR POWER PLANT ENCLOSURES: PRESENT CAPABILITIES

AND FUTURE PROSPECTS 4. DATE REPORT COMPLETED

MONTH y EAR

S. AUTHOR(SI November 1985

B. DATE REPORT ISSUED

JOHN L. BOCCIO AND JOHN L. USHER MONTH YEAR

December 1985

7. PERFORMING ORGANIZATION NAME AND MAILING ADDRESS (ItudeIZ1.0 Code) B. PROJECT/TASK/WORK UNIT NUMBER

BROOKHAVEN NATIONAL LABORATORY

UPTON, NEW YORK 11973 9. FIN OR GRANT NUMBER

FIN A-3252

10. SPONSORING ORGANIZATION NAME AND MAILING ADDRESS (mI.,ud# Z~p Cod.) 1 a. TYPE OF REPORT

DIVISION OF ENGINEERING TECHNOLOGY, RES

OFFICE OF NUCLEAR REGULATORY RESEARCH

U.S. NUCLEAR REGULATORY COMMISSION b PERIOD COVEREO lo.om ... ,date)

WASHINGTON, D.C. 20555

12 SUPPLEMENTARY NOTES

13 ABSTRACT (2I00 Words Or !ef)

This report provides a summary of the work conducted during FY84 by Brookhaven

National Laboratory (BNL), under FIN A-3252 "Fire Protection Research Program."

It was undertaken under the cognizance of the Electrical Engineering Branch in the

Division of Engineering Technology within the Office of Nuclear Regulatory Research.

The report describes a mathematical model for predicting the thermal environment

within complex nuclear power plant enclosures. It demonstrates the capability of the

existing numerical code by direct comparisons with electrical cable fire/large enclosure tests performed by Factory Mutual Research Corporation (FMRC) for the Electric

Power Research Institute (EPRI). It further demonstrates the potential usefulness of

the existing code in addressing fire-protection issues. This is done through a paraumetric study of the thermal environment resulting from a series of fires within

cabinets in a nuclear power plant control room (similar to LaSalle). Also, it presents

an example of how the code can be utilized by addressing an Appendix R exemption

request which deals with the vulnerability of containment fans to a fire emanating

from a reactor coolant pump bay. Recommendations are also given as to how the model/

code can be further enhanced and where current effort is proceeding.

14 DOCUMENT ANALYSIS- 8 KEYWORDSJDESCRIPTORS 15 AVAILABILITY

fire protection pool fires STATEMENT

computer codes field models

control rooms cabinet fires Unlimited

nuclear power plants forced ventilation 16 SECURITY CLASSIFICATION

cable fires complex geometry ,Tr,. ,Afe

b IDENTIFIERSIOPEN.ENDEO TERMS Unclassified

fTh,s IWor)

Unclassified

17 NUMBER OF PAGES

18 PRICE


1 05 5500 5954

US NRC

ACM-DIV 0F TIDC

FRANCH CHIEF

LIBRARY FP

1Fl0

WASHINGTON

2 IANIR7

DC 20553