FIRE MODELING FOR NUCLEAR

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24 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

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FIRE MODELING FOR NUCLEAR
ENGINEERING PROFESSIONALS


An Educational Program to Improve the
Level of Teaching Risk
-
Informed,
Performance
-
based Fire Protection
Engineering Assessment Methods

DJ Icove & AE Ruggles

Department of Nuclear Engineering

1

BACKGROUND


This three
-
day course is based on selected topics
from the U.S. Nuclear Regulatory Commission
(NRC)
Nuclear Power Plant Fire Modeling
Application Guide
(
NPP

FIRE MAG), implemented
by NUREG
-
1934, 2
nd

Draft, issued July 2011.


Your instructors are Dr. David J. Icove and Dr.
Arthur E.
Ruggles

from the University of
Tennessee, College of Engineering


Partial funding for this initiative was through an
NRC Nuclear Educational Curriculum Grant
awarded in 2010 to the Nuclear Engineering
Department, University of Tennessee


2

COURSE SCHEDULE



Monday, August 8, 2011



Introduction



Fire Dynamics Review



Tuesday, August 9, 2011



Fire Modeling in Support of PRA



The Fire Modeling Process



Wednesday, August 10, 2011



Fire Modeling Selection and Implementation



Handling Model Uncertainty


3

1.
INTRODUCTION



4

1.1 Background


In 2001, the National Fire
Protection Association
(NFPA) issued the first
edition of
NFPA 805
,
Performance
-
Based
Standard for Fire
Protection for Light
-
Water
Reactor Electric
Generating Plants


2010 is the latest Edition

5

1.1 Background (Con’t)


Effective July 16, 2004, the Nuclear Regulatory
Commission (NRC) amended its fire protection
requirements in Title 10, Section 50.48(c) of
the
Code of Federal Regulations
(10 CFR
50.48(c)) to permit existing reactor licensees to
voluntarily adopt fire protection requirements
contained in
NFPA 805
following a
performance
-
based approach as an alternative
to the existing deterministic fire protection
requirements.


6

1.1 Background (Con’t)


One important element in a performance
-
based
approach is the estimation of fire hazard using
mathematical fire models.


Fire modeling is one possible approach per
NFPA 805
, to demonstrate compliance with the
regulatory requirements of 10 CFR 50.48(c).


NFPA 805
also allows the use of a fire
probabilistic risk assessment (Fire PRA) in
regulatory applications. Fire modeling is used in
Fire PRAs to determine the effects of fire hazard
so that the associated risk can be quantified.

7

1.1 Background (Con’t)


NFPA 805
states that “fire models shall be
verified

and
validated

and “only fire models that are acceptable to the
authority having jurisdiction (AHJ) shall be used in fire
modeling calculations”


Verification

and
Validation

(V&V) of fire models ensures
the correctness, suitability, and overall quality of the
method.


Verification

determines whether a model correctly represents the
developer’s conceptual description (whether it was “built”
correctly)


Validation

determines whether a model is a suitable
representation of the real world and is capable of reproducing
phenomena of interest (whether the correct model was “built”).

8

1.1 Background (Con’t)


The NRC Advisory Commission on Reactor
Safeguards recommended publication of
NUREG
-
1824 (EPRI 1011999) user’s guide
should include:


Estimates of the ranges of normalized parameters
to be expected in nuclear plant applications


Quantitative estimates of the uncertainties
associated with each model’s predictions,
preferably in the form of probability distributions

9

1.2 Objectives


The objective of this guide (NUREG
-
1934) is to describe
the process of properly conducting a fire modeling
analysis principally for commercial Nuclear Power Plant
(NPP) applications.


This process addresses the selection and definition of
fire scenarios, determination and implementation of input
values, sensitivity analysis, uncertainty quantification,
and documentation.


This guide addresses guidance, recommended best
practices, and example applications the requirements
associated with fire modeling analyses per
NFPA 805
.

10

1.3 Scope


This guide should be used as a complement to,
not a substitute for, “user’s manuals” for
specific fire modeling tools, fire dynamics
textbooks, technical references, education and
training.


Users are encouraged to review the references
made throughout the guide for in
-
depth
coverage of the advantages and the range of
applicability of specific models or assumptions.

11

1.3 Scope (Con’t)


Once selecting a fire scenario, this guide will help the fire
model user to define the necessary modeling parameters,
select an appropriate model, and properly interpret the fire
modeling results.


Due
to the technical
nature of
this guide, users with the
following areas of expertise will benefit the most from it:


General
knowledge of the behavior of compartment fires


General
knowledge of basic engineering principles,
specifically thermodynamics,
heat transfer
, and fluid
mechanics


Ability
to understanding the basis of mathematical models
involving algebraic
and differential equations


Users are cautioned that since all models are merely
approximations of reality, this guide also provides useful
insights for translating real configurations into modeling
scenarios.


12

Common NPP Hazardous Fuels


Combustible Solid Fuels


Cable insulation and pipe insulation


Building materials, combustible roof deck


Filtering, packing, and sealing materials


Low level radioactive wastes


Combustible and Flammable Liquid Fuels


Lubricants, hydraulic oil, and control fuels


Explosive and Flammable Gaseous Fuels


Hydrogen


Propane

13


Electrical cable insulation


Ordinary combustibles


Oil fire hazards in reactor
coolant pump motors,
emergency turbine
-
driven
feedwater pumps


Diesel fuel fire hazards at
diesel
-
driven generators


Charcoal in filter units


Flammable off gases


Protective coatings



Turbine lube oil and
hydrogen seal oil


Hydrogen cooling gas fire
hazard in turbine
generator buildings


Fire hazards associated
with electrical switchgear,
motor control centers
(MCCs), electrical
cabinets, load centers,
inverter, circuit boards,
and transformers

Typical NPP Hazards

14


NPP

FIRE
SCENARIOS

(NUREG 1824)




NPP Fire Scenarios (NUREG 1824)


Switchgear Room


Cable Spreading
Room


Main Control Room


Pump Room


Turbine Building


Multi
-
Compartment
Corridor



Multi
-
Level
Building


Containment
Building


Battery Room


Computer or Relay
Room


Outdoors

16


Switchgear Room Fire




Cable Spreading Room Fire




Main Control Room Fire




Pump Room Fire




Turbine Building Fire




Multi
-
Compartment Corridor Fire




Multi
-
Level Building Fire




Containment Building Fire



25