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October 3, 2017WORKSHOP ON IMPROVING FIRE PRAREALISM -IMPACT ON RISK APPLICATIONSTom BassoDirector -Corporate ProgramsExelon Generation FIRE PRA REALISMImprove Fire PRA realism to better reflect risk due to fire eventsImproved PRA realism allows the industry to move forward using PRA information in risk informed applicationsImplement a probabilistic, data driven approach to fire PRA issues

using available and applicable data that requires no further testingIncorporate operational experience to reflect the number of industry severe fire eventsAny future testing should focus on actual plant design and operational

configurations Streamline the current approach for improving methods and data to meet industry needs (2 year window) 2 FIRE PRA REALISM GOALSNRC Research and EPRI should partner to implement the new EPRI road map to "realistic" fire modelsFire research activities within academia should be pursued

to leverage and accelerate the resolution of issuesExpeditious resolution of impactful fire PRA drivers in the

next 2 years is neededRisk informed applications being sought rely on a realistic fire PRA platformRework of risk

-informed programs will be required if resolution is not implemented in a timely manner Improved fire models facilitate application of insights 3

Victoria Anderson, NEINRC Fire PRA WorkshopOctober 3, 2017Overview of Industry Experience Importance of Fire PRA Realism in Supporting Safe OperationsTransition to NFPA 805 means that Fire PRA

outputs are driving more operational decisionsFuture transitions to 50.69 and TSTF

-505 will increase this impactCritical that decisions are based on accurate

information that comports with operating experience Progress to DateNearly a decade of work improving on original methods outlined in NUREG/CR

-6850Substantial improvements to large

-scale conservatisms (e.g. electrical cabinet heat release rates)Multiple moderate conservatisms remain and, in

aggregate, result in Fire PRAs that still do not comport with operating experience Objectives for WorkshopReview specific conservatisms continuing to drive resultsEvaluate relative impact of various conservatismsInform prioritization of work for research plans

© 2017 Electric Power Research Institute, Inc. All rights reserved.Ashley LindemanSenior Technical LeaderFrancisco JoglarJENSEN HUGHESFire PRA Workshop: Improving RealismOctober 4, 2017Fire Spread Between Adjacent Electrical Enclosures 2© 2017 Electric Power Research Institute, Inc. All rights reserved.Background

-Fire PRAsinclude scenarios where a fire initiated in one electrical enclosure is assumed to propagate to an adjacent enclosure.This is referred to as cabinet

-to-cabinet fire spread in NUREG/CR

-6850A fire is assumed to spread from the electrical enclosure of fire origin (the exposing enclosure) to an adjacent enclosure (the exposed enclosure) after "10

-15 minutes" unless the partition(s) between the two enclosures meet one of two exclusionary configurations. There are no distinctions based on factors that would be expected to influence this behavior. Such factors would include:

-Physical characteristics of both the exposing and exposed electrical enclosures, and

-Fire properties (e.g., peak heat release rate (HRR)) assigned to the exposing enclosure. There is also no limit stated as to how many electrical enclosures might ultimately become involved so the extent of fire spread is

-Under some interpretations, the number of cabinets that may become involved is limited only based on the non

-cabinet fire scenarios.

-Explicitly consider scenario likelihood and characteristics

-Provide guidance for avoiding double

-counting of risk contributions when evaluating propagation between electrical cabinets. Applicable to Bin 4 (main control board), Bin 10 (battery chargers), or Bin 15 (plant

-wide electrical cabinets, non

-HEAF) fire ignition sources.

4© 2017 Electric Power Research Institute, Inc. All rights reserved.TerminologyExposing enclosure: The electrical enclosure where the fire is assumed to originate (referred to as the "exposing cabinet" in NUREG/CR

-6850).Exposed enclosure: An electrical enclosure that is adjacent to the exposing enclosure and to which fire spread may be considered (referred to as the "exposed cabinet" in NUREG/CR-6850).It should also be noted that the term "enclosure" refers to a vertical sections counted as part of electrical cabinets.

5© 2017 Electric Power Research Institute, Inc. All rights reserved.Fire Propagation Rules for Adjacent EnclosuresThe following rules are recommended to be used for determining the likelihood ignition of adjacent enclosures

-The Double Wall Rule:Do not postulate fire spread between adjacent electrical enclosures if both the exposing and exposed enclosures have solid steel panels on their adjacent sides (i.e., the double wall configuration).

-The Open Top/Vertically Oriented Cables Rule:Do not postulate fire spread between adjacent electrical enclosures if: (1) the exposing or exposed enclosure (or both) has (have) an open top; and(2) there is an internal wall between vertical sections, possibly with some unsealed openings; and(3) there are no cables running in an upward direction (i.e., either vertically or diagonally) leading from the exposing enclosure into the exposed enclosure through the partition wall between sections. (Note: all three conditions must be met for the exclusion to apply.)An open top electrical enclosure is defined as one whose top surface (i.e., the horizontal surface at the upper extreme of the side panel(s) is either entirely open or is largely open with obstructions (enclosure panels or framing but excluding objects external to the enclosure such as overhead cables or raceways) blocking no more than 50% of the total top area (e.g., a vented top surface with 50% or more venting).

-Vents positioned on (or in) the vertical side panels of an electrical enclosure, even if adjacent to the top surface, do not meet the top venting criteria.Assessing the openings in a wall panel between sections will require judgment. As a general rule, openings representing up to 5% of the total surface area of the neighboring face would be acceptable under this rule.

-The Very Low Fuel Load Rule:Do not postulate fire spread to any adjacent electrical enclosure if the exposing enclosure has a very lowfuel load per NUREG

-2178.-The Small Enclosure Rule:Do not postulate fire spread to any adjacent electrical enclosure if the exposing enclosure has been categorized as a "small electrical enclosure" per NUREG

-2178.

7© 2017 Electric Power Research Institute, Inc. All rights reserved.Fire Propagation Rules for Adjacent Enclosures (cont.)The following rules are recommended to be used for determining the likelihood of ignition of adjacent enclosures

-The Low Fuel/Steel Partition Rule:Do not postulate fire spread between adjacent electrical enclosures if there is a full steel panel partition between the exposing and exposed enclosures possibly with some unsealed/open penetrations (up to 5% of the total area of the panel partition) in combination with any one of the following conditions:A lowfuel load in the exposing enclosure, orA lowfuel load in the exposed enclosure provided that the combustible fuels in the exposed enclosure do not come into contact with the separating steel partition, orA very lowfuel load in the exposed enclosure provided that the combustible fuels in the exposed enclosure do not come into contact with the separating steel partition.

-The Low Fuel Exposing/Very Low Exposed Rule:Do not postulate fire spread to an adjacent electrical enclosure if the exposing enclosure has a lowfuel load and the exposed enclosure has a very lowfuel load regardless of the nature of the separation/partitions

-no separation, vented, or open partitions

-between enclosures. Note: If you have defaultfuel loading you must assume propagation if there is no separating partition.

-The MCC Rule:Do not postulate fire spread between adjacent motor control center (MCC) vertical sections.

-The Switchgear Rule:Do not postulate fire spread between adjacent switchgear vertical sections.

8© 2017 Electric Power Research Institute, Inc. All rights reserved.Fire Modeling of Adjacent Enclosures Fire spread will be limited to oneadjacent enclosureThe HRR profile for the two adjacent enclosures will follow as:

-The exposing enclosure will be assumed to have reached peak intensity after 12 minutes, and should be assumed to hold that peak intensity for 8 minutes at which time fire decay can be assumed to begin per the guidance provided in NUREG

-CR-6850. -Using the average decay stage times for the tests referenced in NUREG/CR

-6850, the decay phase for the exposing enclosure will last 19 minutes. That is, the exposing enclosure will burn out 39 minutes after ignition.

-Assume the peak fire intensity for the exposing enclosure corresponds to the 98 thpercentile of the peak HRR distribution applicable to the exposing enclosure (i.e., based on size, function, and/or fuel loading conditions).

-Fire spread to an adjacent electrical enclosure should be assumed to occur 10 minutes after ignition of the exposing enclosure, per the most conservative guidance presented in NUREG/CR

-6850. Therefore, the exposed enclosure will begin its growth stage concurrent with ignition at 10 minutes.

-The exposed enclosure will also be assumed to conservatively achieve the 98 thpercentile peak HRR based on the distribution that is applicable to the exposed enclosure. Note that the exposing and exposed enclosures may be characterized by different peak HRR distributions depending on the characteristics of each.

-Consistent with the treatment of the exposing enclosure, the exposed enclosure should be assumed to maintain its peak intensity for 8 minutes, after which it will begin a decay phase that will last no more than 19 minutes for a total fire duration in the exposed enclosure of 39 minutes (49 minutes from exposing enclosure ignition).

01020304050HRR (kW)Time (min)Total Combined HRR (kW)Exposing Enclosure HRR (kW)Exposed Enclosure HRR (kW) 10© 2017 Electric Power Research Institute, Inc. All rights reserved.Consequence for Adjacent Enclosures Fire PropagationWhen fire spread to an adjacent enclosure is postulated, a conditional probability with a value of 0.02, may be applied in the form of a modifier (severity factor) against the frequency of fires initiated in the exposing enclosure or, more correctly, in the form of a split fraction between single

-and multi-enclosure fire scenarios.

-In instances where the rules outlined above suggest propagation in two directions, two options are available for the application of the 0.02 conditional probability: A value of 0.01 (0.02/2) may be used and fire spread may be postulated to the enclosures on either side of the exposing enclosure (Note: When applying the probability in this manner the fire is probabilistically being spread to a singlecabinet in either direction with a modifier of 0.01. Therefore, the HRR profile for such a scenario will only be that of the exposing and a single exposed enclosure), orA value of 0.02 may be used to determine the most risk significant scenario for fire spread among the enclosures in both directions. Once the most risk significant path is determined, fire spread will only be postulated to that single adjacent enclosure.

11© 2017 Electric Power Research Institute, Inc. All rights reserved.IgnitionPropagation to Adjacent CabinetYes - 0.02Source FreqNo - 0.98Pictorial RepresentationExposingExposed 12© 2017 Electric Power Research Institute, Inc. All rights reserved.Together-Shaping the Future of Electricity NRC/INDUSTRY WORKSHOP ON IMPROVING REALISM IN FIRE PRA sREVISED GROWTH CURVE ELECTRICAL PANEL AND TRANSIENT FIRESUsamaFarradjOctober 3, 2017 www.jensenhughes.com 2OUTLINEBasis for Current Electrical Fire Growth CurveApplicability of Approach to Transient FiresImpact of Revised Fire Growth Curve on Non

-Suppression ProbabilityApplication to Sensitivity EvaluationREVISED GROWTH CURVE www.jensenhughes.com 3BASIS FOR CURRENT ELECTRICAL CABINET FIRE GROWTH CURVESElectrical Cabinet Fire Growth CurveNUREG/CR-6850, Section G.3.1, Table G

-6 provides a list and brief description of electrical cabinet tests used to define the fire growth curveTime to Peak, 12 minutes, t 2growth curve8 minutes at peak19 minutes decayGrowth timeframe defined primarily by method of ignition (transient

-16/22, electrical

-3/22, gas

-3/22)Growth curve defines applicable NSPLonger time to peak = longer time to damage = lower NSP www.jensenhughes.com 4TRANSIENT FIRE GROWTHThe same approach outlined for electrical cabinet fire growth may be applied to transient firesA proportional increase in the time to peak for a transient fire

similar to that applied to an electrical panel fire will result in a similar proportional decrease in the corresponding transient fire NSP www.jensenhughes.com 5IMPACT ON SCENARIO NSP OF LONGER TIME TO PEAK HEAT RELEASE RATEUsing e-tcurveDoubling the time to peak (increase from 12 minutes to 24 minutes) results in a reduction of NSP, for a given time, to a value that is the square of the current NSP (NSP 2), using the current NSP for electrical fires the reduction is approximately a factor of 3 (at 12 minutes)Increasing the time to peak by a factor of 1.5 (18 minutes)

results in a reduction of NSP for a given time to a value that is the current NSP1.5, using the current NSP for electrical fires the reduction is approximately a factor of 2 (at 12 minutes) www.jensenhughes.com 6HEAT RELEASE RATE VERSUS TIME 0 50100150 200 250 300 350 400 450 0 10 20 30 40 50 60HRR, kWTime, minutes24 min18 min12 minFOR NUREG-2178, CONFIG 4a, closed panel, 98 th%ile www.jensenhughes.com 7HRR VERSUS NSP0.050.0100.0150.0 200.0 250.0 300.0 350.0 400.0 450.01.000.820.680.560.460.380.310.250.210.170.140.120.10HRR, kWNSP24 min18 min12 minFOR NUREG-2178, CONFIG 4a, closed panel, 98 th%ile www.jensenhughes.com 8METHOD APPLIED FOR SENSITIVITY EVALUATIONNSP for scenarios ar e decreased by a factor of 3 or 2, for peak at 24 min or 18 min, respectivelyDoes not account for additional risk reduction due to the slower rate of increase of the HRR which would provide a longer time to damage using the NUREG/CR

-6850, Appendix H damage accrual dataApplicable to transient fires also The potential exists for additional reduction for transient

fires where a shorter current analysis time to peak is typically usedApproach is applied based on an increased time to peak

heat release curve but is also conservatively representative of incorporation of a fire pre

-growth phase during which the fire may be detected (when smoke detection is present) but the HRR is minimal www.jensenhughes.com 9ContactUsama Farradj+1 925-943-7077ufarradj@jensenhughes.comFor More Information Visitwww.jensenhughes.comQUESTIONS?

Conservatism in Non-Suppression Probability (NSP) DataFPRA WorkshopOctober 3-5 2017Presented by:Mark SchairerEngineering Planning and Management, Inc.

NSP Data ConservatismThere is a disconnect between the average durations of fire scenarios in Fire PRAs vs. fire event experienceNUREG-2169 uses over 400 total fire events from 1981

-2009 for FPRA applications.The fire durations can have time lags or delays associated with reporting, which inflates the fire time.Time to controlthe fire versus time to extinguishthe fireDelays in declaring a fire event extinguished are associated with de

-energizing equipment, offsite fire brigade, and water applicationIn Fire PRAs, the source scenarios reach peak HRR in 12 minutes.

Using FLASH

-CAT, multiple trays are involved well before 20 minutes. Peak ZOI and HGL occur before 20 minutes.

2 Path ForwardFrom the NSP data, more than 25% of fire events have durations longer than 20 minutes. Typically, on

-site fire brigade arrival is expected to be within 5

-10 minutes, and upon arrival, fire is under control within 5

-10 minutes.Additional review of the fire event data would be beneficial to re

-examine when the fires were under control, rather than totally extinguished. At the control point, the fire is no longer a threat to fire spread, hot gas layer formation, additional target damage.

3 Initial AssessmentAdditional fire event information can be obtained from NRC Event Reports, Licensee Event Reports, or through Plant contacts.Some initial scoping of high

-duration electrical cabinet fires from NRC Event Reports:

4EPRI Fire IDEvent DatePower ModeFire SeverityBin DesignationNSPCategorySuppression Time (min)109711/15/1986Low-power operationUndetermined 26Electrical 95 4184/28/1984Low-power operationChallenging 10Electrical 60 64211/4/1987Power operationChallenging15.1Electrical 50 9810/8/1998 RF PC 15Electrical 46 3036212/16/2001 RF PC 21Electrical 45 508299/11/2004 PO PC 23Electrical 45 17511/22/2009 CD CH 15Electrical 45 1214/26/2003 PO U 21Electrical 37 5051/8/1986Low-power operationUndetermined 21Electrical 36 203027/25/1993 PO U 15Electrical 35 2381/24/1981Power operationChallenging 21Electrical 30 5571/31/1987Low-power operationChallenging 22Electrical 30 65612/17/1987Power operationChallenging 22Electrical 30 976/10/1998 PO PC 22Electrical 29 1062612/11/2002 PO PC 21Electrical 27 23512/30/1992 PO PC 26Electrical 25 NSP Data from NUREG

-2169 5Fire Event CategoryTotal Number of EventsSum of Durations [min]Average Duration [min]NSP at t = 20 minT/G Fires 30 116738.90.598Control Room 12 373.10.002PWR Containment 3 4013.30.223Containment (LPSD) 31 2999.60.126Outdoor transformers 24 92838.70.596Flammable gas 8 23429.30.505Oil fires 50 56211.20.169Cable fires 4 297.30.063Electrical fires 177 181510.30.142Welding fires 52 4849.30.117Transient fires 42 3869.20.113High energy arcing faults 8 60275.30.767All fires 442 658314.90.261 Estimate of Improvement: Electrical FiresOf the 177 total fire events, 25 had durations of over 20 minutesSimple exercise: Events over 20 minutes duration were reduced by half, but not less than 20 minutes; Events under 20 minutes were unalteredi.e., 50 min event was reduced to 25 min, while 30 min event to 20 minThe average duration was reduced by ~20%NSP at 20 minutes reduced by 35%

6NSP CurveTotal Number EventsSum of DurationsAverage Duration [min]NSP at time =

20NUREG-2169 177 181510.30.142Estimate of Improvement 177 14928.40.093 SummaryNSP data still conservative with respect to fire durationsMore than 25% NSP after 20 minutes Time to Control versus time to extinguish a fireTime to control is a better data point for plant response and risk/damage assessment.Future work

-review NRC event reports, LERs, and other sources of event information to identify when a fire was controlled, rather than extinguished to refine NSP calculations.

7 Moving towards more Realistic Cabinet DamageRob Cavedo The ConservatismMoving towards more Realistic Cabinet Damage 1All trains and functions that can be affected by a fire are assumed to occur at the cabinet ignition frequency.For most cabinets, this is a mildly conservative assumption (e.g. breaker goes open/breaker goes closed).For cabinets that control multiple trains from different power supplies, this can be overly conservative.Industry events of cabinets with multiple trains do not show the loss of all trains (e.g. single alarm card damaged others functional, single HS malfunction, etc.).

Uninformative Prior ApproachMoving towards more Realistic Cabinet Damage 2Assume each possibility has an equal likelihood of occurrence.For simplification, the impact option should be grouped by train.A train is defined as any equipment in the cabinet powered from the same ultimate external power supply to the cabinet.

If all equipment in the cabinet is powered from the same external source, then this method cannot be applied.This would only apply to scenarios with NO EXTERNAL damage. If the fire is large enough to damage external equipment, then larger internal losses are expected.

ExampleMoving towards more Realistic Cabinet Damage 3Flow controllers for Pump A and C are in Cabinet X.Given a per panel ignition frequency of 1E

-4, the conservative and more realistic results are:Only Benefit in the Fire within a cabinet regionConservative full Cabinet LossImproved Cabinet ModelingCaseDescriptionImpactFrequencyFrequency X1Fire within CabinetFCs A and C Lost 7.00E-052.33E-05 X2Fire within CabinetFC A lost; FC C functionalN/A2.33E-05 X3Fire within CabinetFC C lost; FC A functionalN/A2.33E-05 X4Fire Damages cabinet and TargetFCs A, C and 1st Target2.80E-052.80E-05 X5Fire Damages whole roomWhole Room2.00E-062.00E-0633.3% chance of each impact possibility QuestionsMoving towards more Realistic Cabinet Damage 4

Reduction in the NSP FloorRob Cavedo The ConservatismReduction in the NSP Floor 1The NSP Floor is at 1

-in-1000 for an infinite duration fire.This can be a significant contributor to control room abandonment likelihoods with lower heat release rate scenarios.

Use a 1E-5 FloorReduction in the NSP Floor 2The fire brigade composition and method of operation is similar to a reactor operational response crew.There is a leader directing the actions of the fire brigade members. The leader will bring more and more resources to bear as the scenario progresses.

Sample ImprovementsReduction in the NSP Floor 30.3240.1110.098TimeNSP with Floor 1E-3NSP with Floor 1E-5TimeNSP with Floor 1E-3NSP with Floor 1E-5TimeNSP with Floor 1E-3NSP with Floor 1E-501101 101 1 50.1980.198 50.570.57 50.610.61100.0390.039100.330.33100.380.38150.00770.0077150.190.19150.230.23201.52E-031.52E-03200.110.11200.140.14251.00E-033.01E-04250.060.06250.090.09301.00E-035.95E-05300.040.04300.050.05351.00E-031.18E-05350.020.02350.030.03401.00E-031.00E-05400.010.01400.020.02501.00E-031.00E-05503.81E-033.81E-03507.63E-037.63E-03601.00E-031.00E-05601.25E-031.25E-03602.88E-032.88E-03701.00E-034.11E-04701.08E-031.08E-03801.00E-031.35E-04801.00E-034.09E-04901.00E-034.42E-05901.00E-031.54E-041001.00E-031.45E-051001.00E-035.82E-051101.00E-031.00E-051101.00E-032.19E-051201.00E-031.00E-051201.00E-031.00E-05Control RoomTransientsElectrical Fires BenefitsReduction in the NSP Floor 4The largest benefit is a reduction in the control room abandonment likelihood. For most other types of fires, by the time the floor is used the room is already lost due to a damaging hot gas layer.

Control Room Abandonment Improvement (w NUREG 2178)Reduction in the NSP Floor 5The reduction of the floor can provide a 20% to 50% reduction in the likelihood of control room abandonment. The amount of reduction is on the higher end for control room modeling that credits NUREG 2178. NUREG 2178 has a much higher likelihood of lower HRR fires.Bin, iHRR (kW)SFTime To AbandonmentNSP wo FloorSF*NSP wo FloorContribution wo FloorNSP with FloorSF*NSP with FloorContribution with Floor 1340.161332.27E-053.65E-060.65%1.00E-031.61E-0414.0%

21300.554253.04E-041.68E-0430.05%1.00E-035.54E-0448.5%

32210.205228.02E-041.64E-0429.38%1.00E-032.05E-0417.9%

43100.05919.12.05E-031.22E-0421.71%2.05E-031.22E-0410.6%

54001.61E-0217.253.74E-036.00E-0510.72%3.74E-036.00E-055.3%

64904.03E-0315.670.00622.51E-054.49%0.00622.51E-052.2%

75799.72E-0413.80.01141.11E-051.99%0.01141.11E-051.0%

86692.35E-0412.590.01693.98E-060.71%0.01693.98E-060.35%

97595.47E-0511.820.02171.19E-060.21%0.02171.19E-060.10%108481.25E-0511.30.02573.21E-070.06%0.02573.21E-070.03%119382.90E-0610.760.03068.88E-081.59E-040.03068.88E-087.77E-05121,0286.53E-0710.460.03372.20E-083.94E-050.03372.20E-081.93E-05131,1181.46E-0710.010.03905.71E-091.02E-050.03905.71E-094.99E-06141,2083.25E-089.680.04341.41E-092.53E-060.04341.41E-091.24E-06151,4629.24E-098.640.06085.62E-101.00E-060.06085.62E-104.92E-07Pr(ab)5.60E-04Pr(ab)1.14E-03 QuestionsReduction in the NSP Floor 6

Keith Vincent

-NextEra Energy Fire PRA Technical LeadHEAF Event FrequencyFire PRA Workshop, October 3

-5, 2017 2HEAF Event FrequencyCurrent Fire PRA MethodologyHEAF events modeled using Appendix M of NUREG/CR

-6850Assessment based on operating experience, San OnofreUnit 3 Event from 2001.

-Any vulnerable component with 3' horizontally suffers physical damage

-First overhead cable tray will be ignited if within 5' vertical distance and 1' foot vertical distance of the top of the cabinet

-Ensuing fire reaches peak HRR immediately (no t 2ramp up)Does not differentiate between ignition sources 3HEAF Event FrequencyOperating Experience ReviewReview of Operating Experience has shown that the classification of the electrical device plays a significant role in the potential for there to be a HEAF event.Class 1E equipment has had fewer HEAF events compared with Non-Class 1E equipment

-Class 1E HEAF Events Non-Class 1E HEAF Events

-11 4HEAF Event FrequencySuggested Approach to Increase RealismDevelop a methodology that addresses the differences between Class 1E and Non

-Class 1E electrical equipment.

-Class 1E equipment is subject to higher maintenance and inspection standards and as such common precursors to HEAF events are ameliorated prior to a HEAF event occurring.Utilize operating experience to generate an overall split

-fraction to differentiate the source of the HEAF events. Assign a smaller fraction of the overall HEAF ignition frequency to Class 1E equipment.

-Class 1E Split Fraction

-0.21-Non-Class 1E Split Fraction

-0.79 FAQ 14-0007 TRANSIENT FIRE FREQUENCY ENHANCEMENT Kiang Zee Gregory ZucalFire PRA Workshop, October 3

-5, 2017 www.jensenhughes.com 2BACKGROUNDNUREG/CR-6850 Methodology to distribute transient frequency to Physical Analysis Units (PAUs)Rankings for transient influence factors assigned to each PAUGeneric location frequencies distributed to PAUsPAU frequency apportioned to transient scenarios using floor area ratioFAQ 12-0004 Provided enhancements to account for administrative controls New ranking levels of Very Low and Extremely Low available if criteria is metLimitations of current approachPAUs frequently consist of different types of areas Transient free zonesStorage areasHigh traffic areasNo clear guidance on how to account for variability of ranking values within a PAUFLOOR BASED TRANSIENT FREQUENCY ALLOCATION www.jensenhughes.com 3SUBDIVIDING A PHYSICAL ANALYSIS UNITFollow existing guidance to distribute frequency to PAUsIdentify PAUsfor which sub

-division is warranted to account for varying transient influence factor rankingsDefine Transient Ignition Source Regions (TISRs)Determine applicable floor areaInfluence factor rankings assigned following guidance in FAQ 12-0064PAU DOtherStorageAreaTFZArea Type IDFloorArea n M n O n S n HPAU D 2000 10 3 10 3TISRD_TFZ 200 1 3 1 1TISRD_Storage 400 1 3 10 1TISRD_Other 1400 10 3 3 3PAUBin 7 (GT)Bin 6 (WC)Total D1.53E-031.67E-033.20E-03 www.jensenhughes.com 4CALCULATING TISRFREQUENCIESTransient Ignition Source Region Factor (TISRF)Used to apportion the frequency within a PAU Considers TISRinfluence factor rankings and sizes of TISRs(available floor areas)TISR FrequencyProduct of PAU frequency and TISRFUsed to apportion frequency to scenarios instead of PAU frequencyEquationsSimilar to the PAU apportionment equations in FAQ 12

-0064 with addition of floor area termnA,k,Jis the available floor area for TISR'k' within PAU 'J'kJkAJkSJkOJkMJkAJkSJkOJkMJk GTnnnnnnnnTISRF])[()(,,,,,,,,,,,,,,,,,,kJkAJkHJkAJkHJk WCnnnnTISRF,,,,,,, ,,,JkpJpkpTISRF,,,,*

www.jensenhughes.com 5CALCULATING TISRFREQUENCIESTransient Ignition Source Region Factor (TISRF)Used to apportion the frequency within a PAU Considers TISRinfluence factor rankings and sizes of TISRs(available floor areas)TISR FrequencyProduct of PAU frequency and TISRFUsed to apportion frequency to scenarios instead of PAU frequencyEquationsSimilar to the PAU apportionment equations in FAQ 12

-0064 with addition of floor area termnA,k,Jis the available floor area for TISR'k' within PAU 'J'TISRFloorArea n M n O n S n HFA*Sum(n)FA*nHTISRF GTTISRF WCBin 7 (GT)Bin 6 (WC)TotalFA RatioFreqDistD_TFZ 200 1 3 1 1 1000 2000.03 0.04 5.28E-056.94E-051.22E-0410.0%3.8%D_Storage 400 1 3 10 1 5600 4000.19 0.08 2.96E-041.39E-044.35E-0420.0%13.6%D_Other 1400 10 3 3 3 22400 42000.77 0.88 1.18E-031.46E-032.64E-0370.0%82.6%Total 2000----29000 48001.00 1.00 1.53E-031.67E-033.20E-03 100%100%

www.jensenhughes.com 6IMPACT ON SCENARIO FREQUENCIESScenarios frequencies calculated using floor area ratio of TISRIf transient scenario spans TISRs, frequency calculated per TISRand then combinedThe TISRmethodology allows risk informed administrative controls to be reflected in future PRA model updatesFrequency may increase in areas for which administrative controls were not appliedPAU DD_T3OtherD_T4StorageAreaTFZD_T2D_T1ScenarioFloorArea [ft2]Ratio (PAU)Freq(PAU)Ratio (TISR)Freq (TISR)% ChangeD_T11000.0501.60E-040.5006.11E-05-62%D_T21500.0752.40E-040.3751.63E-04-32%D_T32000.1003.20E-040.1433.77E-0418%D_T4 (Storage)500.0257.99E-050.1255.43E-05-32%D_T4 (Other)500.0257.99E-050.0369.43E-0518%D_T4 (Combined)1000.0501.60E-04N/A1.49E-04-7%

www.jensenhughes.com 7ContactGregory Zucal+1 610-431-8260gzucal@jensenhughes.comFor More Information Visitwww.jensenhughes.comQUESTIONS?

High Energy Arcing Fault (HEAF) Non

-Suppression Probability (NSP)Fire PRA FAQ 17

-0013FPRA WorkshopOctober 3-5 2017Presented by:Mark SchairerEngineering Planning and Management, Inc.

IntroductionThe non-suppression probabilities (NSP) for high energy arcing fault (HEAF) fires provided in NUREG/CR-6850 Supplement 1 (FAQ 08

-0050) and NUREG 2169 are considered conservative.Fire event durations used for NSP extend past the

control point in the fire event. As a result, the risk associated with HEAFs in critical

fire areas may be artificially high.

2 ApproachA review of LERs was conducted to assess whether HEAF non

-suppression probability (NSP) guidance per NUREGs 6850 and 2169 is overly conservative.HEAF fire durations were reviewed to reduce the time to when the

fire is considered to be controlled (i.e., when fire spread has been arrested, the ZOI has reached it's peak and when the threat of further damage, or hot gas layer is minimal).

3BIN 16 HEAF Analysis# EventsTotal DurationAVG time/eventMean Suppression Rate (/min)NUREG/CR-6850 3 23979.670.013NUREG/CR-6850 Supplement 1 3 27692.000.011NUREG 2169 8 60275.250.013 Revision to Fire Event TimesCommon factors in the reported events that contributed to extended durations past the control point in the fires. There is a delay between when the fire is under control in the field and when it is reported to the control room as extinguished.There is a delay in reporting when the fire is declared extinguished

due to the need to de

-energize high energy equipment.The time to control the fire is more relevant to potential damage impacts than full extinguishment.Five (5) fire event durations have been revised based on the above.

4 Revision to Fire Event Times 5EPRI Event IDNUREG/CR-6850 Supp. 1 Duration (min)NUREG-2169 Duration (min)Revised Duration (min)Justification 947 -(OC 19890103) 59 59 46Plant personnel suppressed and controlled the fire at 46 minutes with CO2 extinguishers to the origin. The additional 13 minutes per NUREG

-2169 accounted for water-based extinguishment.

74 -(WF 19950610) 76 136 80The local fire department applied water to the insulation above the bus duct at ~80 minutes, the fire would be considered sufficiently controlled at that point.

100 -(DC 20000515)N/A 78 35LER states that the fire brigade "extinguished the fire" after 35 minutes, well before offsite assistance, which later cleared the room of smoke and declared the fire extinguished after 78 minutes.

106 -(SG 20010203) 141 154 31The fire was suppressed and controlled after 30 minutes according to plant personnel (flames no longer visible). Additional time was due to complete extinguishment concerns over de

-energization and resistance to using water. 127 -(VY 20040618)N/A 71 37The fire brigade reported the fire was under control after 37 minutes, but it not declared extinguished until 71 minutes.

Additional Fire Events 6During the review, two fire events were identified that were binned as electrical fires for NSP in NUREG

-2169, butare HEAFs for ignition frequency. Event #922

-bus bar fire connecting to Main Aux Transformer from 6160 volt busses caused by fault to ground, it exhibited characteristics of a typical HEAF fire (secondary fires, de

-energizing equipment, resistance to water use). Fire duration of 5 minutes per the LEREvent #792

-occurred in the "A" isolated

-phase bus duct due to damaged ground straps and weathering. The bus ducts were required to be de

-energized prior to suppression. Fire duration of 3 minutes per the LERAn additional event included in EPRI's most recent FEDB, Fire event #162 (8/5/2009) is a HEAF fire with a 46 minute duration.

Revised NSP 7BIN 16 HEAF Analysis# EventsTotal DurationAVG time/eventMean Suppression Rate (/min)NUREG/CR-6850 3 23979.670.013NUREG/CR-6850 Supplement 1 3 276 920.011NUREG 2169 8 60275.250.013FAQ 17-0013 -(including Bus Ducts)11 38535.00.029FAQ 17-0013 excluding Bus Ducts)9 37741.890.024Using the revised (5) HEAF fire durations, the other three (3) HEAF events in NUREG 2169, and event 162Compare with and without the 2 bus duct events Comparison with International EventsThe Organization for Economic Co

-operation and Development (OECD) report: Fire Project Topical Report No. 1 "Analysis of High Energy Arching Fault (HEAF) Fire Events"Incorporates data from HEAF events in 10 countries (excluding USA)The OECD average duration of HEAF events outside the US was 31.3 minutesThe OECD average duration of HEAF events, both US and International is 32.7 minutesFAQ 17-0013 proposes an average duration of 35 min (41.89 w/o Bus Ducts), which is conservative WRT international data.

8 Summary/Conclusions 9SuppressionCurveNumber ofEventsin CurveTotal Duration(minutes)Average Duration (minutes)MeanT/G fires 30 116738.80.026Control room 12 373.10.324PWRcontainment(AP)3 4013.30.075Containment(LPSD)31 2999.60.104Outdoor transformers 24 92838.70.026Flammable gas 8 23429.30.034Oil fires 50 56211.20.089Cable fires 4 297.30.138Electrical fires 175 180710.30.097Welding fires 52 4849.30.107Transientfires 43 3869.20.111HEAFs 11 38535.00.029All fires 443 635814.350.070 Alternative ApproachFor the HEAF events in the database, the new average time to suppression is 35.0 (41.89) minutes.It can be argued that the fire is controlled early on, and

propagation to trays had either burned out or this portion of the fire had been extinguished successfully earlier on. Thus, in PRAs, the longer duration HEAF scenarios, which may lead

to HGLs, etc. are much more likely in line with an electrical cabinet, or cable fire NSP curve. Therefore, the HEAF fires that are evaluated at time periods well

beyond the HEAF itself (i.e., 20 minutes) use the electrical cabinet or cable tray NSP and lambda mean value. 10 Summary/ConclusionsNUREG-2169 HEAF data includes durations that are conservativeIt is proposed that the mean suppression rate be increased

by approximately a factor of two (from 0.013 to 0.024 (0.029)) to reflect the revised average fire duration for HEAFs originating in high energy equipment in the US. Preliminary set of comments received from NRCEPRI/NRC/NEI Task Force to jointly review and discuss the

comments.11 FAQ 16-011 Bulk Cable Tray IgnitionRob Cavedo The ConservatismFAQ 16-011 Bulk Cable Tray Ignition 1

Modeling with ConservatismFAQ 16-011 Bulk Cable Tray Ignition 2For FLASH-CAT, the recommended value of HRR per unit area is:150 kW/m^2 for thermoset cables and250 kW/m^2 for thermoplastics.For a medium cabinet 6' tall with 3 trays 1' above the cabinet, this is a 1.2 MW fire in 20 minutes 3.7%of the time.Cabinet Scenario Frequencies given 205 C IgnitionCabinet Only4.40E-05Cabinet with Tray Stack Lost1.77E-05Whole Room Lost2.35E-06This is for a single cabinet. There are hundreds of cabinets that in the aggregate contribute to risk.This credits 2178 HRR distribution and obstructed plume.

A Few Wise Sites -Flame Ignition of Trays OnlyFAQ 16-011 Bulk Cable Tray Ignition 3A few sites modeled that tray ignition/spread only occurs when the cables are exposed to flame. This was explicitly approved in a few Safety Evaluation Reports (SERs). This was implicitly approved in a few other SERs.This was the original inspiration for this FAQ. This FAQ translates the flame ignition requirements to the equivalent fire model thresholds.Flame Tip Temperature CTp(centerline) - Ta Ta C474.9454.920.000500.4470.430.000526.0486.040.000551.5501.550.000577.0517.060.000Possible flame tip temperatures in a nuclear power plant using the NUREG 1805 spreadsheets.

Revised Cable Impact Table for Bulk Ignition/SpreadFAQ 16-011 Bulk Cable Tray Ignition 4This is based on:NUREG/CR-7010 ResultsNUREG/CR-5384 InsightsOnly flame causes cable ignition (already approved in several SERs)Limited contribution of arcing failures to overall spread/HRR contributionFlux equivalent to 500 C from THIEF Equation 2.6 (NUREG/CR 6931 Vol 3)

Modeling with Realistic Tray IgnitionFAQ 16-011 Bulk Cable Tray Ignition 5For a medium cabinet 6' tall with 3 trays 1' above the cabinet, this is a 1.2 MW fire in 20 minutes 1.3%of the time.Cabinet Scenario Frequencies given 205 C IgnitionCabinet Scenario Frequencies given 500 C IgnitionCabinet Only4.40E-054.40E-05Cabinet with Tray Stack Lost1.77E-051.92E-05Whole Room Lost2.35E-068.25E-07As the cable damage criteria remains the same, the benefit is a factor of 3 reduction in whole room loss scenarios.

Day-to-Day ImpactFAQ 16-011 Bulk Cable Tray Ignition 6Current Cabinet Install Screening ApproachAll trays must be more than 8' above a medium closed cabinet. If not, then multiple fire scenarios must be analyzed to determine growth issues. This is very complicated. This involves walkdown of conduits and trays near the closest tray to the cabinet.Post FAQ Cabinet Install Screening ApproachAs long as the closest tray is more than 4' away. Propagation need not be considered. The evaluation would simply be the cabinet itself and a scenario with the cabinet and those targets in the plume. This is a much less complicated evaluation.

QuestionsFAQ 16-011 Bulk Cable Tray Ignition 7

NRC/INDUSTRY WORKSHOP ON IMPROVING REALISM IN FIRE PRA sCable Fire SpreadUsama FarradjOctober 3, 2017 www.jensenhughes.com 2OUTLINEFire Scenarios with Cable Tray Intervening CombustiblesNSP Lambda ValuesNSP for Electrical Fire versus NSP for Cable FireSuggested ApproachCABLE FIRE SPREAD www.jensenhughes.com 3FIRE SCENARIOS WITH CABLE TRAY INTERVENING COMBUSTIBLESFires associated with electrical panel, transient and other ignition sources which impact electrical cable trays may result in ignition of cables in the cable trays and fire spread along the cable traysFire scenarios involving both electrical cabinet fires and cable tray fire spread

transition from electrical cabinet fires to cable tray fires at the time when the electrical cabinet fire growth rate begins to decay (at 20 minutes per current fire growth rate assumptions, NUREG/CR

-6850, Section G.3)Benefit is primarily for electrical panels since transient fires do not have a

timeframe in which their HRR decreases from the peak value www.jensenhughes.com 4LAMBDA VALUE (MEAN SUPPRESSION RATE) COMPARISON www.jensenhughes.com 5COMPARISON OF NSP VALUE OVER TIME0.00010.0010.010.1 1 0 10 20 30 40 50 60 70 NSPTime (minutes)NSP ComparisonCable NSPElect NSPCombined NSP at 20 min www.jensenhughes.com 6SUGGESTED APPROACH TO INCREASE REALISMTransition NSP curve from Electrical to Cable NSP curve at 20 minutesIncorporation of this approach to fire in large volumes where HGL is reached after 20 minutes would allow reduction of risk based on application of a more appropriate NSP value for the period during which the cable fire is the primary source of HRRCurrent fire data supporting the NSP curve for cable fires is limited but can be

supplemented with future fire events data www.jensenhughes.com 7ContactUsama Farradj+1 925 943

-7077ufarradj@jensenhughes.comFor More Information Visitwww.jensenhughes.comQUESTIONS?

OBSTRUCTED RADIATION ZOIJason Floyd, PhDFire PRA Workshop, October 3

-5, 2017 www.jensenhughes.com 2OBSTRUCTED RADIATIONPOINT SOURCESOLID FLAME www.jensenhughes.com 31D APPROXIMATION,,,+,=,+,Painted surface: ==0.95 Thin metal wall: ,,=900;=25=50/K(Forced due to flame)=10/K(Natural)=719NRL/MR/6180-03-8711 (2003)(heptane spray fire against steel bulkhead) www.jensenhughes.com 4MODELING APPROACHESOpen DoorNo accounting for radiation shieldingFlow dynamics incorrect1 Grid Cell Wide LouversSome radiation shieldingIf < ~5 grid cells across each

slot, will not resolve pressure drop through louvers www.jensenhughes.com 5SELECTED MODELING APPROACHDefine multiple &HVAC leakage paths over the height of the cabinet.Assign each path the actual

open area of the louver(s)No direct flame radiation

from inside the cabinetLocalized Leakage www.jensenhughes.com 6FDS GEOMETRY MODELSOpen FaceClosed (Louvered) Face www.jensenhughes.com 7ZOI FOR STEADY STATE FIRES 00.5 11.5 22.5 3 0 1 2 3FDS ZOI (m)FDT ZOI (m)N TPE/W TPS TP 00.5 11.5 22.5 3 0 1 2 3FDS ZOI (m)FDT ZOI (m)N TSE/W TSS TSFDS predicted ZOI of zero means no ZOI outside the cabinetVariables: cabinet size, cabinet shape, fire size, fire shape+location www.jensenhughes.com 8At threshold exposure it takes 19 minutes for damage to occur (NUREG/CR

-6850 Tables H

-7,H-8)NUREG/CR-6850 Table G-2 heat release profile12 min. growth8 min. steady

-state19 min. decayTIME DEPENDENT HEAT RELEASE RATE 8 00.20.40.60.8 11.2 05001000150020002500Normalized ProfileTime (s)HRRWall Temp19 min www.jensenhughes.com 9Simple threshold exposurePeak exposure reaches NUREG/CR

-6850 App HConservative as discussed on prior slideTime dependent exposureAssume damage occurs in a linear fashion with a rate given by the corresponding entry in Appendix HAt 6 kW/m 2thermoplastic cable is damaged at a rate of 1/19 min.Below threshold exposure, adjust rate assuming the same total energy deposition is required (e.g. 3 kw/m 2would be 1/38 min)Integrate the damage rate over timeDamage occurs when the integral exceeds 1TARGET DAMAGE 9

www.jensenhughes.com 10METHOD 1 -TARGET SCREENING A BB= Obs_fac* A www.jensenhughes.com 11METHOD 2 -REDUCED SEVERITY FACTOR EC www.jensenhughes.com 12METHOD 2 -REDUCED SEVERITY FACTOR www.jensenhughes.com 13ContactName+1 410-737-8677jfloyd@jensenhughes.comFor More Information Visitwww.jensenhughes.comQUESTIONS?

Integrating OE into NUREG

-2180 (FAQ 17-012)Harold Stiles -Lead Engineer PSA VEWFDS Performing Beyond Its Design Basis August 2013 Timeline OE Has Been Used In NUREG-2180OE was used to meet certain project objectives for NUREG

-2180:Item C: Human Reliability AnalysisItem D: System Availability and ReliabilityItem E: System response to common products of combustion applicable to NPPWhile not a specific project objective, OE was also used in NUREG

-2180 to estimate the:Duration of the incipient stageFrequency of a potentially challenging fires having an incipient stage of sufficient duration Event Tree for Quantifying the Risk Benefit of VEWFDSPrevention and SuppressionNo OE for fire in cabinet with VEWFDSFocus on External TargetsPrevention does not result in "No Fire"Poor reporting of Incipient PhaseSuppression fails entire cabinet Split fraction conflicts with HRAAbbreviated Incipient Duration NRC feedback on FAQ 17

-012NRC identified several serious faults with the methodology:Crediting limited, possibly irrelevant, data for human intervention rather than HRA methodsUsing non-suppression methodology to credit preventionDirectly using Appendix L, rather than a method like Appendix L, beyond its intended application Inadequate technical justification for:Changing the incipient stage threshold without collecting data (Appendix G of NUREG

-2180)Assuming the ALARM occurs prior to the start of the fireEstablishing the incipient stage duration and the time availableUsing the MCR non

-suppression probability for area

-wide applicationsNRC also provided detailed review comments:Provide a different event treeSeparate area

-wide applications from in

-cabinet applicationsAddress potential for low

-energy events never progressing to a potentially challenging fireIndustry initiative to collect data (Appendix G) could provide a basis for crediting VEWFDSClarify roles for prevention/suppression and related dependenciesProvide basis for suppression agent not failing entire cabinetNRC also provided additional comments during a face

-to-face exchange Proposed Event Tree for Quantifying the Risk Benefit of VEWFDSSuccessful prevention results in "No Fire"Targeted Suppression does not fail entire cabinetInitiating Event is notbased on Bin 15 frequency Expected Results with Cloud Chamber ASD Reasonable results with modest HEPs Expected Results with Light Scattering ASDLimitations of lesseffective equipment Considerations for Parameter EstimationIncipient Event FrequencySection 6.5.1 of NUREG/CR

-6850 provides guidance for treatment of unique ignition source types that are not reflected in the generic frequency model ignition source list. Incipient events would only be considered when attributed to a monitored component and terminated either by actual fire or by intervention prior to fire.When an incipient event is terminated by intervention prior to fire, the characteristics (e.g., low

-energy, temperature relative to ignition threshold) of the specific component should be considered to assign a partial count reflecting the likelihood of the incipient event progressing to an actual fire.When an incipient event is terminated by fire or by intervention (if partially counted), the characteristics of the surroundings (e.g., contents of affected cabinet) should be considered to classify the event into a fire severity group (e.g., challenging, potentially challenging) Duration of incipient stageGiven the lack of available information, NUREG

-2180 acknowledged expert elicitation as one approach to develop a consensus or community opinion.The expectation is that a consensus or community opinion would result in a significantly longer incipient stage duration. For application to a particular ignition source, the most realistic duration of the incipient stage would be a composite distribution based on the number, types, and failure modes of associated components

.

Going ForwardIndustry initiative to collect VEWFDS data comparable to Appendix G:ApplicationNumber and type of ignition sources (e.g., BIN 15 or BIN 4)for which VEWFDS is creditedNumber and type of components comprising the ignition sourceCapable of being de

-energized at the panel or component levelAdministrative control in place to support a responseLevel of detail in proceduresRoles of responsible personnel (e.g., decision maker)Pre-stage equipmentOperating experienceDefining t(end) based on t(de

-energize) is misleadingAnalyze and Report Incipient Results (EPRI document)Incipient Event FrequencyIncipient Stage DurationEstablish a Process for Maintaining and Periodically Updating Incipient Results UNOBSTRUCTED RADIATION ZOIJason Floyd, PhDFire PRA Workshop, October 3

-5, 2017 www.jensenhughes.com 2FDT APPROACHES L DD/2+LPoint Source"=42+ L F L F D LSolid Flame"=E=emissive powerF=view factor H

www.jensenhughes.com 3POINT SOURCE L D L FUnderlying assumption is that the target's view factor, F, of the fire is near zero.Shokri+Beyler: D/2 + L > 2.5 Max(D,L F)Contemp. Health Phys: D/2 + L > 3 Max(D,L F)SourceSize(kW)Diameter (m)Flame Height (m)DistanceRatio 11(kW/m 2)6(kW/m 2)1.7(kW/m 2)Small EC 450.340.730.40.61.1Medium EC 3250.691.70.50.71.3LargeEC1,0001.02.70.60.71.4100 gal spill670,000 26 241.62.24.1 www.jensenhughes.com 4SOLID FLAME L F D LSolid Flame"==58x10.==,=, S H=,==From Shokri

-Beyler(large hydrocarbon fires) www.jensenhughes.com 5SOLID FLAMEPump, motor,transient, EC, &

small oil spill firesLarge oil fires (e.g. TB) www.jensenhughes.com 6PROPOSED SOLID FLAME CHANGES=Min58x10.,=Min 1 ,58x10.Adjust Emissive Power:

OrAdjust Target Flux:

www.jensenhughes.com 7VALIDATION (FLUERY)0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35Predicted Heat Flux (kW/m2)Measured Heat Flux (kW/m2)Solid FlameSolid Flame, Adjusted E 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35Predicted Heat Flux (kW/m2)Measured Heat Flux (kW/m2)Solid FlameSolid Flame, Adjusted EAll Tests1:1 Aspect RatioNew approach has lower error and bias (bias is still positive) www.jensenhughes.com 8VALIDATION (NIST/NRC) 0 5 10 15 0 5 10 15Predicted Heat Flux (kW/m2)Measured Heat Flux (kW/m2)Solid FlameSolid Flame, Adjusted E 0 10 20 30 40 0 10 20 30 40Predicted Heat Flux (kW/m2)Measured Heat Flux (kW/m2)Solid FlameSolid Flame, Adjusted EMost are larger fires (> 1 MW), correction is minorNew approach has lower error and bias (bias is still positive)All TestsOutlier RemovedBurner location underneath gauge, solid flame not appropriate www.jensenhughes.com 9VALIDATION (WTC) 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70Predicted Heat Flux (kW/m2)Measured Heat Flux (kW/m2)Solid FlameSolid Flame, Adjusted ELarger fires (> 1 MW), correction is minorNew approach has lower error and bias (bias is still positive)

High scatter due to test objectives www.jensenhughes.com 10ContactName+1 410-737-8677jfloyd@jensenhughes.comFor More Information Visitwww.jensenhughes.comQUESTIONS?

ML17284A214

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