ML13078A255

03/19/2013-03/21/2013 Licensee Meeting Slides Re Joseph M. Farley Nuclear Plant NFPA 805 Fire Modeling LAR Submittal - Session 10

ML13078A255
Person / Time
Site:	Farley
Issue date:	03/19/2013
From:	Southern Nuclear Operating Co
To:	Ellen Brown Plant Licensing Branch II
Brown E
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ML13078A284	List: ML13078A245 ML13078A246 ML13078A247 ML13078A248 ML13078A250 ML13078A251 ML13078A252 ML13078A253 ML13078A255
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FNP Fire Modeling LAR Submittal Oi O verv i ewMarch 19, 2012FireModelingOverview Fire Modeling Overview Fire Modeling TopicsThe purpose of this presentation is to describe the fire modeling applications at FNC that are used to support thNFPA805liibiFidlii th e NFPA 805 li cens i ng b as i s. Fi re mo d e li ng i s performed in one of three general areas:*Generic Fire Modeling Treatments-Original report (2008)Slt12d3-S upp l emen t s 1 , 2 , an d 3*Main Control Room Abandonment CalculationMGStMtZOICllti

• MG S e t M o t or ZOI C a l cu l a ti on FM Overview Slide 2of 20 Generic Fire Modeling Treatments Treatments*PurposeQantif/tablatetheZOIdimensionsarondplantignition

-Q u antif y/tab u late the ZOI dimensions aro u nd plant ignition sources*NUREG/CR-6850 ignition sources (bins)Cbtiblliidillfi

• C om b us tibl e li qu id sp ill fi res-Quantify/tabulate the time to reach threshold HGL temperatures*ZOI Concept-ZOI is defined by one or more lateral dimensions and a vertical dimension-Th e Z O I i s assoc i ated wi t h a steady state da m age t hr es h o l d eOsassocatedtasteadystatedaagetesod heat flux*5.7 kW/m² (thermoplastic/non-IEEE-383 qualified cables*11.4 kW/m² (thermoset/IEEE-383 qualified cables FM OverviewSlide 3of 20 Generic Fire Modeling Treatments Treatments*ZOI Calculation-Uses empirical plume models and steady state damage thresholds*Includes same models used in NUREG-1805; selects most adverse amon g all models used g-Variable fire diameter/area (via heat release rate per area)*Ignition SourcesFiNUREG/CR6850ltill(fiftHRRbi

-Fi ve NUREG/CR-6850 e l ec t r i ca l pane l s cases (fift een HRR bi ns each)-Transient (fifteen HRR bins)

-Unconfined/confined liquid fire-Cable tray stacks (applicable to thermoplastic cables only)

FM OverviewSlide 4of 20 Generic Fire Modeling Treatments TreatmentsTransient ZOI DimensionsPanel ZOI Dimensions FM OverviewSlide 5of 20 Generic Fire Modeling Treatments Treatments*ZOI Im p lementation p-98 thpercentile ZOI dimensions assembled in walkdown form-Largest horizontal ZOI dimension used when there are multiple dimensions(panels) dimensions (panels)-Vertical ZOI dimension used if no secondary combustibles in ZOI

-Ceiling height used do define vertical ZOI dimension if secondarycombustiblesareinZOI secondary combustibles are in ZOI-Vertical ZOI dimension is relative to:*The fire base (transient and combustible liquid fires)Thfl(lfi)*Th e fl oor (pane l fi res)*The lowest tray in stack (cable tray fires)

FM OverviewSlide 6of 20 Generic Fire Modeling Treatments Treatments*Key ZOI Limitations (Original Document)

-Nosecondarycombustibles(seeSupplement2)

No secondary combustibles (see Supplement 2)-No hot gas layer effects-Open fire configuration*Hot Gas Layer Effects on ZOI Dimensions-A modified critical heat flux is used to establish reasonable maximum tem perature and to extend ZOI a pp licabilit ypppy*80°C alters critical heat flux by about 1 kW/m² and is considered the maximum value beyond which non-conservative results could be

generated*Not a required limitation for plume and heat flux models in NUREG-1805 (same methods), but model bias is low due to HGL effects-Used to extend ZOI for some target classes FM Overview Slide 7of 20 Generic Fire Modeling Treatments Treatments W/m 2)10 12/s-ft 2)1.0IEEE-383 Cablenon-IEEE-383 Cable Thermoset cableThermoplasticcable al Heat Flux (k W 6 8 10l Heat Flux (Btu

/0.60.8Class A combustible Thermoplastic cableClass A combustibleModified Critic a 2 4Modified Critica0.20.4Immersion Temperature (°C)050100150200250300350 0ImmersionTemperature(°F)1002003004005006000.0Temperature range forthermoset cable target ZOIImmersion Temperature (F)Temperature range for thermoset cable target ZOI characterized using thermoplastic target ZOI FM OverviewSlide 8of 20 Generic Fire Modeling Treatments Treatments*Wall and Corner ConfigurationsWithin2ftofawallorcornerboundary

-Within 2 ft of a wall or corner boundary-'Image' Method used*Chan ge entrainment characteristics of model plume to account for gpcorner or wall:-Model HRR -2 or 4 X Bin HRR (wall or corner)

-Model fire diameter is 2 1/2 or 2 X Bin fire diameter (wall or (corner) to maintain constant Q/A*Change enclosure characteristics to accommodate 'virtual' portions of model fire plume:-Wall and ceiling area doubled/quadrupled-Natural and forced ventilation flow paths/volumes doubled/quadrupled FM Overview Slide 9of 20 Generic Fire Modeling Treatments Treatments*Hot Gas Layer Tables

-List time the HGL reaches threshold value in generic enclosure-Tabulated by:*Fire size*Enclosure volume*Leakage fraction

-For a g iven fire size and enclosure volume

, the minimum time g,among all leakage fractions is selected-Generic enclosure derived from sensitivity runs:*Minimizes surface area*Adiabatic floor*Three potential vent combinations for each scenario FM OverviewSlide 10of 20 Generic Fire Modeling Treatments Treatments H e=0.63 V1/3 W exL exH e= V H e=0.63 V1/3 W exL exH e= V A 3 A 1= A 2= A 3 A 3 A 1= A 2= A 3 A 1= A 2= A 3 L e=1.26 V 1/3 L e=1.26 V 1/3 A 1 A 2 H e W e or L e W e or L e A 1 A 2 H e W e or L e W e or L e W e=1.26 V1/3 W e=1.26 V1/3Vent Orientation 1Vent Orientation 2Vent Orientation 3Vent Orientation 1Vent Orientation 2Vent Orientation 3Generic SpaceVent Orientations FM OverviewSlide 11of 20 Generic Fire Modeling Treatments Treatments*Verification

-IndependentreviewofallcalculationsperformedusingExcel Independent review of all calculations performed using Excel*Validation-Most applications include at least one fire scenario that falls ithithNUREG 1824diilt w ithi n th e NUREG-1824 non-di mens i ona l parame t er space-Additional basis is provided in LAR Attachment J for plume and heat flux applications that fall outside the NUREG-1824 non-diilt di mens i ona l parame t er space-CFAST simulations include a geometry that by definition conforms with NUREG-1824 validation range. At least one ihiltithtfllithithNUREG scenar i o h as an equ i va l ence ra ti on th a t f a ll s w ithi n th e NUREG-1824 validation range.

FM OverviewSlide 12of 20 Generic Fire Modeling Treatments Treatments*Supplement 1: Closed Panel HRR EstimatesUilidlkfiihd

-U ses vent il at i on an d l ea k age area f ract ions w i t h mass an d energy balance to determine maximum internal HRR-Results compared with available test data (verification) and htbtihtlbiibd s h own t o b e conserva tive w hen no ex t erna l b urn i ng i s o b serve d or the door does not fail*Supplement 2: Expanded HGL Tables-Original Generic Fire modeling treatment approach expanded to include:*Time-de pendent fires p*Secondary combustibles (two side-by-side, 18 inch wide cable trays Ignited at five minutes at a point above a panel; lateral flame spread per NUREG/CR-6850 recommended rates)

FM Overview Slide 13of 20 Generic Fire Modeling Treatments Treatments*Supplement 3: Transient Ignition Source Characteristics (ThilRt)(T ec h n i ca l R epor t)-Characterizes ZOI sensitivity to assumed fire diameter or area-Determines fire area/diameter range for transients based on NUREG/CR-6850 test data-Identifies special case of 98 th percentile transient

-Identifies 98 th percentile transient fire duration based on ener gy pgy content-Provides revised ZOI dimensions based on 98 thfire area and fire duration-Uses same methods as original Generic Fire Modeling Treatments report to generate revised ZOIs FM OverviewSlide 14of 20 Main Control Room AbandonmentCalculation Abandonment Calculation*Pur p ose p-Tabulate the abandonment time for ignition sources present in the MCR

-Provide a sensitivity study of the abandonment times to parameter uncertainty

• Method*Method-CFAST, Version 6.1.1 used

-NUREG/CR-6850OpticalDensity(OD)and NUREG/CR 6850 Optical Density (OD) and temperature criteria used to define abandonment FM Overview Slide 15of 20 Main Control Room AbandonmentCalculation Abandonment Calculation*NUREG/CR-6850 Fire Scenarios (15 HRR Bins Each)

-Panel(closedsingle/multiplebundlenon

-IEEE-383qualified)

Panel (closed , single/multiple bundle , non IEEE 383 qualified)-Panel fire that propagates to adjacent panels (open, non-IEEE-383 qualified cables)

Transient-Transient*Multiple Geometric/Boundary Configurations-Normal HVAC/no HVAC/purge mode-Boundary door open/closed/open at 15 minutes-Operating area/equipment area

• 1080BaseSimulations(4firesX15binsX9Geometries

• 1080 Base Simulations (4 fires X 15 bins X 9 Geometries X 2 Locations)

FM Overview Slide 16of 20 Main Control Room AbandonmentCalculation Abandonment CalculationMCRPlanComputer Rooms(sameHVACZone)

FM OverviewSlide 17of 20 MCR Plan (same HVAC Zone)

Main Control Room AbandonmentCalculation Abandonment Calculation*Sensitivity Analysis (Appendix B)

-Nineparametersassessedforeachignitionsource(Bin14fires)

Nine parameters assessed for each ignition source (Bin 14 fires)-Low sensitivity observed in most computed abandonment times (typically +/-1 -2 minutes or less)

• Someparametersconservativelybiased

• Some parameters conservatively biased*Some parameter are not conservatively biased-Sensitivity is not expected to affect the order of magnitude of risk AdiDPidDiifVifitid

• A ppen di x D P rov id es Di scuss ion o f V er ifi ca ti on an d Validation/Benchmark Installation

-Includes com p arison a gainst NUREG 4527, Vol. 2 test cases pg (validation)-Includes comparison against NUREG 1824 simulations (verification and validation

)()FM OverviewSlide 18of 20 MG Set Motor ZOI Calculation*NUREG 1805 Com p utation p-Thermal plume temperature (vertical ZOI dimension)-Thermal radiation model (horizontal ZOI dimension)

-Enclosurehotgaslayersensitivityanalysis(AppendixB)

Enclosure hot gas layer sensitivity analysis (Appendix B)*Analysis Follows NUREG-1934 Process

• Verification Provided by NUREG-1824 *Applications Outside of NUREG-1824 Validation Range-Results are used with conservative bias

-LARAttachmentJprovidesadditionalbasisforapplication LAR Attachment J provides additional basis for application FM OverviewSlide 19of 20 FNC Fire Modeling Overview Questions?

FM OverviewSlide 20of 20