U-603132, Provides Responses to Fire Questions Three,Four & Five Re Ipeee.Listed Commitment Contained in Ltr

Provides Responses to Fire Questions Three,Four & Five Re Ipeee.Listed Commitment Contained in Ltr

ML20198N659
Person / Time
Site:	Clinton
Issue date:	12/28/1998
From:	Walter MacFarland ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
U-603132, NUDOCS 9901060181
Download: ML20198N659 (30)

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llhnois Power Company Cl!nton Power Station i

P O. Box 678 i

Chnton,IL 61727 Tel 217 935-5623 Fax 217 9354 632 Walter G. MacFarland IV j

Senior Vice President.

i and Cheef Nuclear Omcer L

P9WER Lag 32 An Illinova Company December 28,1998 Docket No. 50-461 i

Document Control Clerk Nuclear Regulatory Commission Washington, D.C. 20555 i

Subject:

Response to AdditionalInformation Request Regarding Fire Questions for the Clinton Power Station Individual Plant Evamia=* ion of External Events (IPEEE)

I

Dear Madam or Sir:

By letter dated February 25,1998, from Jon B. Hopkins, the NRC requested

- additional information regarding the Clinton Power Station (CPS) Individual Plant Examination of External Events (IPEEE) submittal in the seismic and fire damage areas.

In letter U-602986 dated April 27,1998, Illinois Power (IP) committed to respond to the fire questions three, four and five of the February 25,1998, request for information by December 31,1998.

I The purpose of this letter is to provide responses to the fire questions three, four and five. The responses to the subject fire questions are contained in Attachment 1 to l

this letter.-

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Additionally, in letter U-602986, IP committed to submit a schedule for

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response to fire questions one and two by December 31,1998.- IP is collaborating with

' the Electric Power Research Institute (EPRI) to answer fire questions 1 and 2, which are generic to the industry. EPRI's generic resolutions for these questions are expected t

in the first quarter of 1999. Following the EPRI resolution of these generic issues, IP will respond to or submit a revised schedule for its re::ponse to the IPEEE request for t

additional information concerning fire questions one and two.

' The following commitment is contained within this letter:

e' Following the resolution of the EPRI generic issues associated with fire O

j

. questions 1 and 2, IP will respond to or submit a revised schedule for IPEEE response.

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U-603132 l

Page 2 Ifyou have any questions, please contact me.

Sincerely yours, 0.

f, n.

b Walter G. MacFarland, IV l

Senior Vice President and ChiefNuclear Officer i

.MEM/krk i

Attachment cc:

NRC Clinton Licensing Project Manager NRC Resident Office, V-690 i

Regional Administrator, Region III, USNRC Illinois Department of Nuclear Safety i

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U403132 Page1of28 l.

NRC Ouestion 3 The Main Control Room (MCR) analysis employs a non-suppression probability of 3.4E-3. The use of this value is equivalent to assuming that control room operators are equally effective as optimally-placed in-cabinet smoke detectors in detecting fires. Please provide additionaljustification for this assumption, including a discussion of possible MCR fire scenarios (including their locations, initial severities, and progression) and the effects of control room ventilation. Also describe the fire detection system in the underfloor area and discuss the impact on j

detection due to the use ofTefzel cables.

Illinois Power Response i

i The Main Control Room fire protection system is designed to detect a fire, alert control room personnel, and suppress the fire. This is accomplished through the i

use of thermal detectors, ionization detectors and Halon 1301. Detection and suppression is provided for the floor sections within the control room and detection is provided for the panels and termination cabinets. Additionally, all the Power Generation Control Complex (PGCC) modules have removable floor plates, j

lateral duct covers and fire stops.

The MCR fire protection system is a Class A system in accordance with National Fire Protection Association document " Proprietary Protective Signaling Systems -

1975" (NFPA 72D-1975). All CPS Main Control Room panels, including the horseshoe panel (P680), have in-cabinet ionization detectors. Ionization and thermal detectors are provided in the underfloor area in the longitudinal channels.

Fire stops were installed at the intersection of the longitudinal and lateral channels.

Ceiling ionization detectors are also installed, above and below the false ceiling, to l

protect again t transient and other potential sources, such as data printers. In l

addition, there are four smoke detectors in each termination cabinet and smoke detectors are also located in the MCR panel bays.

l-Each MCR floor section contains at least four smoke detectors and eight thermal detectors, with fire stops installed in the cable ducts. Fire suppression equipment l

is installed along with the detection system in the floor section. The fire l

suppression equipment consists of four nozzles attached to a manifold typically located at the termination cabinet end of the floor section. Each nozzle is designed to flood each longitudinal raceway. The suppressant, Halon 1301, has a low toxicity rating, is electrically non-conductive, leaves no residue and does not react with the materials in the control room. The Halon 1301 extinguishing agent is introduced into the floor section cable ducts, providing at least a 6% concentration ofHalon within 10 seconds of activation; and with sufficient Halon to maintain this concentration for at least 10 minutes. In addition, the floor plate design allows for quick removal so that the MCR operators may use the locally mounted, hand-held fire extinguishers,ifrequired.

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U-603132 Page 2 of 28 The cables used in the CPS main control reom are coated with Tefzel insulation and jacketing. Tests conducted by GE and Tefzel manufacturer, DuPont, show a slow rate of fire growth along the exposed Tefzel cable. Because of the sensitivity of the in-cabinet ionization detectors, they are considered an effective means for l

early warning even with the Terzel cable insulation.

The ionization detectors in the control room, both in the floor area and in the cabinets, provide local audible and visual alarms within the MCR when products of combustion are detected. In addition to the local alarms, operation of any audible l

alarm on the fire protection central control station also alarms a common annunciator on a Balance of Plant (BOP) annunciator panel located in the MCR.

In the IPEEE fire analysis, an in-cabinet fire is esem=1 to fail the entire safety-i related division and/or the BOP equipment associated with each cab' met. Impact of the fire is evaluated using the CPS fault tree and event tree models by setting the l

basic events associated with the impacted equipment to TRUE, and setting the appropriate initiating event probabilities to 1.0. For cabinets containing BOP equipment only, a simultaneous loss ofPlant Service Water, Feedwater, and Instrument Air Systems are assumed as the initiator, and for the Divisional l

cabinets, a transient without isolation is assumed. The Probabilistic Risk l

Assessment (PRA) model is then quantified to obtain the cabinet specific conditional core damage probabilities (CCDP). After quantification, the non-suppression probability was credited for the applicable scenarios.

Because the ionization detectors are within the cabinets themselves or are within the floor sections, the effects ofMCR ventilation on fires within the MCR are small. The main impact the ventilation system has on fire scenarios is associated with evacuation times. As stated in the IPEEE submittal, the plant-specific factors such as room volume and ventilation were checked against the Sandia test facilities to ensure appropriate use of these tests to determine the time of smoke obscuration. Based on these comparisons,15 minutes time was estimated to be available before smoke would visibly obscure the control panels.

Because of the presence, location, and sensitivity of the MCR ionization detectors with respect to the early warning of fires (even fires associated with Tefzel cable l

insulation), and because of the training of the MCR operators on how to respond l

to a fire in the control room, a non-suppression probability of 3.4E-3 is believed to be reasonable.

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U-603132 Page 3 of 28 j

NRC Ouestion 4 The submittal notes the importance of fire suppression to the plant core damage frequency (CDF) in the observation that not crediting fire suppression raises the plant CDF by a factor of 266 (section 4.6.2). The unreliability of the suppression system is stated as 2%.

Such low unreliability may be reasonable for systems designed, installed, and maintained in accordance with industry standards, such as National Fire Protection Association (NFPA).

It is difficult to understand the result in terms of a simple sensitivity to the non-suppression l

probability since this can account for a factor of fifty, at most in the contribution of this i

scenario.

Please provide an explanation of this result that includes the modeling assumptions in evaluating conditional core damage probabilities e

l (CCDPs) of any sub-scenarios, including their dependence on the non-suppression probability, the expression used to determine the contribution to the CDF, e

the parameter values used and theirjustifications, such as whether the suppression e

l systems were installed and maintained in accordance with industry standards, l

should errors be identified, a new estimate of the contribution to the CDF.

Ulinois Power Response l

l In the fire PRA analysis, sprinklers were credited to reduce the calculated core damage frequency from individual transient ignition source fire scenarios in fire zones CB-2, CB-4 l

and CB-3a. Fire zones CB-2 and CB-4 are the Division 2 and Division 1 Cable Spreading -

l Rooms respectively. Fire zone CB-3a is the DC/UPS Equipment area. To perform a l

simple sensitivity study, the core damage frequency associated with each of these fire l

zones (which is the sum ofindividual fire scenarios developed for each fire zone) could be l

multiplied by a factor of 50 to remove credit for operation of the sprinklers. When this is done, as is shown on Table 4-1, the calculated fire core damage frequency (CDF) increases by a factor of 2.66 or 266%. It is apparent that the difference between the l

number reported in the IPEEE fmal report and the above sensitivity analysis is the result of a typographical error in which the decimal point or percentage sign was inadvertently omitted from the IPEEE report.

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o U-603132 1

Page 4 of 28 TABLE 4-1: SIMPLE SENSITIVITY ANALYSIS TO DETERMINE AFFECT l

OF SPRINKLERS ON CORE DAMAGE FREQUENCY CONTRIBUTION l

CDF in IPEEE CDF with Credit for Report Multiplier to Remove Sprinklers Removed l

Fire Zone (1/yr)

Sprinklers (1/yr)

Al-a 3.25E-10 1

3.25E-10 l

Al-b 1.79E-10 1

1.79E-10

)

A-2k 2.95E-07 1

2.95E-07 A-2n 7.11E-07 1

7.11E-07 A-3d 1.27E-07 1

1.27E-07 A-3f 2.00E-07 1

2.00E-07 CB-1c 2.04E-08 1

2.04E-08 CB-Id 5.36E-10 1

5.36E-10 CB-le 1.14E-09 1

1.14E-09 CB-1f 6.85E-08 1

6.85E-08 CB-2 3.97E-09 50 1.99E-07 CB-3a 1.05E-07 50 5.25E-06 CB-4 1.39E-09 50 6.95E-08 CB-Sa 1.36E-07 1

1.36E-07 CB-6a 1.20E-06 1

1.20E-06 CB-6d 3.72E-08 1

3.72E-08 F-1a 4.28E-10 1

4.28E-10 F-Im 1.11E-08 1

1.11E-08 ip 1.13E-09 1

1.13E-09 M 2c 3.38E-07 1

3.38E-07 9.-It 4.75E-09 1

4.75E-09 Total 3.26E-06 8.67E-06 This results in a factor increase of 2.66 if credit for the sprinklers is removed.

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l U-603132 Page 5 of 28 i

SUPPLEMENTAL INFORMATION PERTAINI 4G TO NRC OUESTION 4 To confirm the magnitude of the affect of the sprinklers on CDF a more rigorous review 1

of the original fire PRA analysis was performed. Credit for reducing CDF using the sprinklers was identified in two portions of the analysis. First, the sprinklers were credited in reducing the CDF associated with a single compartment analysis. Second, the Sprinklers were used to screen some multi-compartment scenarios from further consideration. Each of these aspects of the analysis is discussed in the following sections.

(Note: sprinklers were not credited during the initial screening process in which single compartment fire zones were eliminated from detailed fire modeling.)

A scenario-by-scenario fire analysis was performed for each single compartment or multi-compartment scenario that did not screen from detailed analysis. For the detailed analysis section 1 (below) describes the modeling assumptions of the analysis, the CDF expressions used, the parameter values used, and the justification for using the values selected.

Section 2 (below) presents the new estimate of the non-suppression probability contribution to CDF.

Additionally, during this confirmation effort, a review of Table 2 of the CPS IPEEE Submittal identified that the Ignition Frequencies associated with four zones that were screened from further analysis did not match the values calculated on the supporting worksheets for those zones. For these cases, the four impacted zones were verified to still be below the Screening CDF value of IE-7 using the more conservative of the two Ignition Frequencies. In addition, it was verified that the more conservative Ignition Frequency value was used in the multi-compartment analysis.

SECTION 1 A.

MODELING ASSUMPTIONS USED IN THE ANALYSIS The input decks for each individual scenario were developed based on the assumptions outlined in Section 4.3.3 of the CPS IPEEE submittal and the following assumptions and modeling techniques:

1.

Single Compartment Analysis Assumptions Cables enclosed in conduit that are within the damage range from an ignition source l

are assumed to sustain fire damage and are evaluated for impact on CCDP. These cables are assumed to not propagate fire; however, due to the limited amount of oxygen within the conduit, and are therefore, not considered as ignition sources themselves.

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U-603132 Page 6 of 28 Once the target set of cables and equipment associated with each fixed or transient e

ignition source were identified, all equipment associated with this target set were identified and were assumed to be disabled by the fire. In order to model this assumption, the basic events associated with the impacted equipment were set to "true"in the PRA model.

I Applicable accident initiator (s) for each ignition source, as determined based on the e

equipment impacted by the fire, were assumed to occur in the analysis. In order to model this assumption, the applicable accident initiators were set to 1, and all other s

initiators in the PRA model were set to 0.

Fire suppression was only credited in three fire zones, and was assumed applicable for only the transient ignition source scenarios. The three fire zones where fire suppression was credited are CB-2, CB-3a, and CB-4.

2.

Multi-Compartment Analysis Assumptions For the multi-compartment analysis, the potential for hot gas layer (HGL) formation e

was evaluated for the fire zones in the plant. Fire zones without the potential for HGL formation were screened from further evaluation as potential exposing zones. Fire zones without the potential for HGL formation in a two-room zone combination were also screened from further analysis. Fires associated with the fire zones with the potential for HGL formation in a two-room zone combination were assumed to disable all the equipment in both rooms. In order to model this assumption, the basic events associated with all impacted equipment in the combined zone were set to "true" in the PRA model.

Applicable accident initiator (s) for each multi-compartment scenario, as determined based on the equipment located in the combined rooms, were assumed to occur in the analysis. In order to model this assumption, the applicable accident initiators were set to 1, and all other initiators in the PRA model were set to 0.

B.

CDF EXPRESSIONS 1.

Siagle Compartment Analysis In accordance with Fire Probabilistic Risk Assessment (FPRA) methodology, the p

following generic expression was used to determine the scenario specific CDF for the Single Compartment Analysis:

CDF = (Ignition Frequency) * (CCDP) * (Non-Suppression Probability) 4 1

___-__.___._-.m._.

Anachment 1 U-603132 Page 7 of 28 This equation was modified based on the terms applicable to the specific scenario being evaluated. The ignition frequency and CCDP terms were applicable to all scenarios. The non-suppression probability was only applicable to the transient ignition source scenarios associated with fire zones CB-2, CB-3a, and CB-4. When a term was not applicable to a scenario, or was applicable but not credited, the term was, in effect, set to one. The i

values applied for each term in the equation were determined as follows:

L a.

Ignition Frequency:

i Fixed Innition Sources: The ignition frequency for each fixed ignition source was calculated following the guidance in the FPRA methodology.

Transient Ianition Sources: For the transient ignition source scenarios, the fire zone ignition source frequencies were determined based on the number and types ofFPRA specified activities not prohibited within the fire zone. The physical area associated with a transient combustible fuel package fire, referred to as the damage area, was measured. The ratio of each transient combustible damage area over the fire zone floor area was then calculated. This ratio represents the probability that a transient combustible is located in the area affecting a particular target set. These area ratios were multiplied by the fire zone ignition source frequency to determine the transient combustible ignition frequency for each target set.

- b.

CCDP:

Once the target set of cables and equipment associated with each ignition source were identified, modeled equipment associated with this target set were identified, and were assumed to be disabled by the fire. Potential accident initiator (s) for each ignition source were determined based on the equipment impacted by the fire. In order to calculate the scenario specific CCDPs, the basic events associated with the impacted equipment were set to "tme" in the PRA model, the applicable accident initiators were set to 1, and all other initiators in the PRA model were set to 0. The PRA model was then re-solved.

c.

Non-Suppression Probability:

The FPRA methodology specifies a non-suppression probability of 2.0E-2 for wet pipe sprinkler systems, and a non-suppression probability of 5.0E-2 for pre-action sprinkler systems. These values were determined to be appropriate since the fire suppression systems at CPS were initially designed, installed and inspected in l

accordance with the NFPA codes and standards as documented in the CPS USAR.

In addition, the fire suppression systems continue to be inspected and tested in accordance with approved procedures that comply with NFPA recommendations.

The non-suppression probability is applicable to the scenarios associated with rooms that were determined to have whole zone sprinkler systems in them. This L

results in the non-suppression probability being potentially applicable for scenarios involving fire zones CB-2, CB-3a, and CB-4. The original analysis assumed that

U-603132 Page 8 of 28 fire zones CB-2, CB-4, and CB-3a all had whole zone wet pipe sprinkler systems.

While verifying this assumption, it was identified that although fire zones CB-2 and CB-4 have whole zone wet pipe sprinkler systems, fire zone CB-3a has a whole zone pre-action sprinkler system.

2.

Multi-Compartment Analysis In accordance with the FPRA methodology, the following generic expression was used to determine each scenario specific CDF for each Multi-Compartment scenario that was not screened based on HGL considerations:

CDF = (Ignition Frequency) * (CCDP) * (Barrier Failure Probability) *

(RSP Probability) * (Non-Suppression Probability)

This equation was modified based on the terms applicable to the specific scenario being evaluated. The ignition frequency, CCDP, and barrier failure probability terms are potentially applicable to all scenarios. The Remote Shutdown Panel (RSP) probability term is associated with crediting the operators with being able to manually control required equipment from the RSP when the Main Control Room controls are not functioning properly as a result of cable dependencies associated with the postulated fires.

The non-suppression probability term is associated with crediting the sprinklers in the impacted rooms with either suppressmg a fire or preventing the development of a HGL in

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the rooms. The non-suppression probability term was determined to be applicable to those scenarios involving rooms CB-2, CB-3a, and CB-4. When a term was not applicable to a scenario, or was applicable but not credited, the term was set to one.

a.

Ignition Frequency:

The ignition frequency for each multi-compartment scenario used the ignition frequencies associated with the exposing zone as calculated for the single compartment screening analysis.

b.

CCDP:

1 The CCDP associated with multi-compartment scenarios were determined in the same manner as for single compartment scenarios with one exception: fires associated with the multi-compartment scenarios were assumed to disable all the modeled equipment in both rooms.

c.

Barrier Failure Probability:

The barrier failure probability for each multi-compartment scenario was determined by 4

summing all the individual penetration failure probabilities for the wall separating the exposing and adjacent compartments. The per.etration failure probabilities speci6ed in the FPRA methodology were used for each individual penetration.

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Attachnwnt 1 U-603132 Page 9 of 28 d.

RSP Probability:

CPS hes remote shutdown capability for both Division 1 and Division 2 as discussed in Section 4.3.4.b of the CPS IPEEE Submittal. This capability can significantly impact the multi-compartment scenarios where or.e or both of these divisions are affected by a fire and random equipment failures prevent the use of other safe shutdown paths. A detailed RSP recovery analysis was performed for the MCR fire scenarios to determine the appropriate values to use when RSP is credited in a scenario. The values determined in the MCR fire aralysis ranged from 0.25 to 0.01 depending upon which RSPs were being used. Use of RSP Division 1 alone was determined to have a failure probability of 0.01; use of RSP Division 2 alone was determined to have a failure probability of 0.1; and use of RSP Division 2 after RSP Division I had been tried remotely and failed was determined to have a failure probability of 0.25. For the multi-compartment analysis, the most conservative value for crediting use of a single RSP, 0.1 based on RSP Division 2, was determined to be potentially applicable for all the multi-compartment scenarios that did not screen out initially, e.

Non-Suppression Probability:

Non-suppression probabilities associated with the multi-compartment analysis follow the same rules as for the single compartment analysis discussed above.

SECTION 2: NEW ESTIMATE OF NON-SUPPRESSION PROBABILITY CONTRIBUTION TO CDF A.

Single Compartment Analysis Assumptions used in the fire modeling process are described in Section 1. In gensal the process used to calculate core damage frequencies for the single compartment a:utlysis can be summarized as follows. The associated CDF for the single compartment analysis scenarios was typically calculated as the product of the CCDP and the ignition frequency terms. In instances where the sprinklers were credited, the affect of the sprinklers was to reduce this product by multiplying by the non-suppression probability of the sprinider.

The non-suppression probability used in the original CPS analysis was 2E-2, or a factor of

50. This is the value specified in the Fire PRA Implementation Guide for wet pipe sprinider systems. Although that assumption is valid for fire zones CB-2 and CB-4, it is not true for fire zone CB-3a. Fire zone CB-3a has a pre-action sprinkler system. Based upon the Fire PRA implementation Guide a non-suppression probability of SE-2 (or a factor of 20 reduction) would have been more appropriate for this type of system. This discrepancy, when corrected, would result in about a 1% increase in the core damage frequency over the value reported in the IPEEE final report.

_m Attachment I l

U-603132 l

Page 10 of 28 The aggregate effect of removing credit for sprinklers from the modeled single room fire scenarios is determined by increasing the CDFs by a factor of 50 for only those scenarios in which the sprinklers were credited in the first place. As noted previously sprinklers were credited to reduce the calculated core damage frequency from individual transient ignition source fire scenarios in fire zones CB-2, CB-4 and CB-3a. For fire events occurring within a single fire zone even the factor of 266 % is somewhat overstated because no credit was taken for the sprinklers to address fixed ignition sources within fire zone CB-3a. There are no fixed ignition sources identified for the cable spreading rooms CB-2 and CB-4. When the factor of 50 increase is applied only to those scenarios where it was credited in the first place, the core damage frequency goes up by a factor of 1.34 or 134%. This is shown in Table 4-2.

i B.

Multi-Compartment Analysis The Multi-compartment analysis performed for CPS is discussed in CPS IPEEE Report Section 4.3.5 l

The IPEEE final report reported no CDF contribution from multi-compartment analysis in the total CDF associated with fires. This is because all multi-compartment scenarios were screened from further analysis. In some cases the pairs were screened out on the basis of deterministic considerations (e.g., insufficient BTU loading to cause HGL formation in both compartments). In other instances the multi-compartment pairs were eliminated on l

the basis of probabilistic considerations. In these instances, if the multi-compartment l

scenario (exposing room and adjacent room pair) had a calculated screening CDF ofless than IE-6 /yr it was eliminated from further consideration. This is the screening threshold specified for multi-compartment analysis in the Fire PRA Implementation Guide. The l

supporting documentation for the fire PRA shows that some multi-compartment scenarios eliminated using the latter method cralited sprinkler systems to reduce the overall probability of the multi-compartment scenario below the IE-6 /yr. criteria. Therefore, in a more rigorous sensitivity analysis for the affects of the sprinklers, consideration should be given to those multi-compartment scenarios that were screened based on the reduction in calculated CDF due to the sprinklers.

From the record of the multi-compartment analysis 14 multi-compartment pairs were identified that would not have screened initially if credit for sprinklers had not been taken.

j In the original analysis, once a means of screening the multi-compartment pair was found, i

the analyst did not gather more information about the multi-compartment scenario. These 14 pairs had calculated a screening probability based upon ignition frequency, barrier failure probability, an assumed worst-case CCDP of 1.0, and the sprinider non-suppression probability. When scenario specific CCDPs for the multi-compartment target set are applied along with a non-recovery factor (0.1) for remote shutdown capability these multi-compartment pairs would again screen from the multi-compartment analysis, even without the benefit of the sprinkler systems. Therefore, when credit for sprinklers is removed from the multi-compartment analysis, other methods (consistent with the Fire PRA 3

l Implementation Guide) can be used for screening out these multi-compartment scenarios.

The end result is that all multi-compartment scenarios screen out and that there is no

U-603132 Page 11 of 28 reported CDF contribution from multi-compartment scenarios even when credit for the sprinklers is removed. See Table 4-3 for the results of the multi-compartment screening when credit for sprinklers is removed.

C.

Conclusion When credit for sprinklers is removed from the Fire PRA analysis the core damage frequency is 1.34 times larger than the value reported in the IPEEE final report (from 3.26E-6 /yr to 4.39E-6 /yr). However, as discussed above the cc,rrected CDF crediting sprinklers is 3.29E-6 instead of 3.26E-6 as reported in the CPS IPEEE Submittal.

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U-603132 Page 12 of 28 TABLE 4-2: SENSITIVITY ANALYSIS TO DETERMINE TIIE AFFECT OF SPRINKLERS ON CORE DAMAGE FREQUENCY CONTRIBUTION FOR SINGLE ROOM MODELED FIRE SCENARIOS CDF in IPEEE Multiplier to CDF with Sprinklen Corrected CDF with Fire Zone Report Remove Reinoved from Applicable Sprinkler Sprinklen (1/yr)

Sprinklers Scenarios Reduction Factor Corrected (1/yr)

Applied (1/yr)

Al-a 3.25E-10 1

3.25E-10 1

3.25E-10 Al-b 1.79E-10 1

1.79E-10 1

1.79E-10 A-2k 2.95E-07 1

2.95E-07 1

2.95E-07 A-2n 7.1lE47 1

7.1lE-07 1

7.11E-07 A-3d 1.27E-07 1

1.27E-07 1

1.27E-07 A-3f 2.00E-07 1

2.00E-07 1

2.00E-07 CB-Ic 2.04E-08 1

2.04E 08 1

2.04E-08 CB-Id 5.36E-10 1

5.36E-10 1

5.36E-10 CB-1e 1.14E-09 1

1.14E 09 1

1.14E-09 CB-1f 6.85E-08 1

6.85E-08 1

6.85E-08 CB-2 3.97E-09 50 1.99E-07 50 3.97E-09 CB-3a Fixed Sources 8.74E-08 1

8.74E 08 1

8.74E-08 CB-3a Transient Sources 1.76E-08 50 8.80E-07 20 4.40E-08 CB-4 1.39E-09 50 6.95E-08 50 1.39E-09 CB-Sa 1.36E-07 1

1.36E-07 1

1.36E-07 CB4a 1.20E-06 1

1.20E-06 1

1.20E-06 CB-6d 3.72E-08 1

3.72E-08 1

3.72E-08 F-la 4.28E-10 1

4.28E-10 1

4.28E-10 F-Im 1.1IE-08 1

1.1IE-08 1

1.11E48 i

F-1p 1.13E-09 1

1.13E 09 1

1.13E-09 M-2c 3.3&E-07 1

3.38E-07 1

3.38E-07 R-It 4.75E-09 1

4.75E-09 1

4.75E-09 Total 3.26E-06 Total 4.39E-06 Total 3.29E-06 This results in a factor increase of 1.34 if credit for the sprinklers is removed completely. A factor increase of 1.01 with respect to the Base Case CDF value is experienced if the corrected sprinkler reduction factors are applied.

Attachment I U-603132 Page 13 of 28 TABLE 4-3: MULTI-COMPARTMENT SCENARIOS THAT WOULD NOT HAVE SCREENED OUT FROM s

THE ORIGINAL ANALYSIS IF CREDIT FOR SPRINKLERS WAS REMOVED CDF when Probability CDF w/o Scenario Screening Multiplier Sprinklers CCDP for Recovery Sprimiders but Screens Exposing Adjacent CDF*

to remove Removed Multi-Remote SD with CCDP &

CCDP &

Fire Zone Fire Zone (1/yr)

Sprin2ders (1/yr)

Compartment Panet RSP Applied RSP Applied (1/yr)

CB-3b CB-2 4.68E-07 50 2.34E-05 1.69E-01 1.00E-01 3.95E-07 Yes CB-3b CB-3a 5.98E-07 50 2.99E-05 1.25E-01 1.00E-01 3.74E-07 Yes CB-3c CB-2 2.23E-08 50 1.12E-06 1.69E-01 1.00E-01 1.89E-08 Yes CB-3c CB-3a 6.90E-07 50 3.45E-05 1.22E-01 1.00E-01 4.21E-07 Yes CB-3d CB-2 2.23E-08 50 1.12E-06 1.77E-01 1.00E-01 1.98E-08 Yes CB-3d CB-3a 5.51E-07 50 2.75E-05 1.22E-01 1.00E-01 3.36E-07 Yes I

CB-3e CB-2 3.58E-07 50 1.79E-05 1.77E-01 1.00E-01 3.17E-07 Yes CB-3e CB-3a 7.49E-08 50 3.74E-06 1.22E-01 1.00E-01 4.57E-08 Yes

[

CB-3f CB-3a 9.98E-08 50 4.99E-06 3.%E-01 1.00E-01 1.53E-07 Yes l

CB-3f CB-4 3.64E-07 50 1.82E-05 3.04E-01 1.00E-01 5.53E-07 Yes t

CB-3g CB-3a 5.28E-07 50 2.64E-05 1.22E-01 1.00E-01 3.22E-07 Yes CB-3g CB-4 2.30E-08 50 1.15E-06 3.52E-01 1.00E-01 4.06E-08 Yes CB-5b CB-4 9.02E-08 50 4.51E-06 1.00E+00 1.00E-01 4.51E-07 Yes t

R-It CB-2 2.39E-07 50 1.20E-05 1.61E-01 1.00E-01 1.92E-07 Yes j

• The Screening CDF is the product of the exposing fire zone initiating frequency, the barrier failure probability and the sprinkler non-suppression probability. The original analysis for these multi-compartment pairs did not include a specific calculation of the multi-compartment CCDPs, but, in effect, assumed a worst case CCDP of 1.0.

P

-a

+

1 l

to U-603132 Page 14 of 28 NRC Ouestion 5 The IPEEE submittal does not address initiating events (e.g. loss-of-coolant accidents, loss of offsite power, etc.) caused by fire as a separate subject. No list is provided as to which initiating events were analyzed and no description is provided concerning final conclusions as to which initiating events are possible. It is also difHcult to understand which system failures lead to core damage for various fire scenarios. The submittal does not explain how the event trees and fault trees were developed / modified for the fire CDF evaluation. Please provide the following information:

a list ofinitiating events that were addressed, as well as the conclusion and basis as to which e

initiating events could be caused by fire in each fire zone, an explanation of how the event trees and fault trees were developed and/or modified for the e

fire risk assessment, a listing of dominant core damage sequences in terms of areas involved, system-train failures, e

and CDF contribution for the most significant fire scenarios.

Illinois Power Response For each fire zone in the plant, any modeled equipment or cables associated with modeled equipment that are located within the fire zone were identified. These lists of cables were then used to determine the affected equipment and develop the lists of basic events to be failed for each fire zone. Any fire zone that did not contain any modeled cables or equipment was screened from further analysis.

The first step in the evaluation was to perform a screening analysis. This screening analysis involved the determination of two pieces ofinformation for each fire zone. The first was the conditional core damage probability (CCDP) for the fire zone and the second was the fire zone ignition frequency. Simply stated, the CCDP is the conditional probability that core damage will occur given that a fire has damaged all the equipment in the fire zone, and the ignition frequency is the probability per time that a fire starts in the fire zone.

In order to determine the most severe impact of a potential fire, the fault trees and event trees were modified for each individual scenario by failing the basic events associated with modeled equipment and cables located in that zone. Then the resulting PRA model was re-solved. Certain types of basic events were determined not to occur as a result of a fire and were not failed prior to solving the model. These non-fire susceptible basic event types are as follows:

valve plugged or obstructed e

Heat exchanger fouling check valve opening and closing failures e

miscalibration ever.ts e

maintenance restoration errors e

e tank failures orifice plugged e

i e

strainer plugged

-. - - ~ - --.

+

to U-603132 Page 15 of 28 The list of equipment associated with each fire zone was reviewed by the Fire PRA analyst and a CPS Senior Reactor Operator (SRO) to determine which CPS PRA accident initiators would result from the loss of the identified equipment. Some of the fire zones reviewed were found not l

. to have the poten',ial for any accident initiator to occur. In this case the transient without isolation accident initiator was added to the list of basic events to complete the SETS computer code input deck. For the fire zones where one or more accident initiators could potentially occur from a fire, all appropriate accident initiators were added to the individual basic events lists. Solution of the CPS PRA model was performed using the SETS computer code with all applicable initiators set to 1 for each zone, all other initiators set to 0, and all applicable basic events set to true (basic l

events were " omega'd").

j l

Table 5-1 provides a listing ofinitiating event identifiers with their descriptions, and a listing of l

fire zones where a fire could potentially cause the initiating event to occur.

i i

Table 5-1: Initiating Event Summary Table l

1 Initiating Event Initiating Event Fire Zones l

' Identifier' Description l

YTRANISTRX Transient WithIsolation A la, A-lb, A-2f, A-2k, A-2n, A-3d, A-3f, i

CB-lb, CB-Ic, CB-le, CB-If, CBli-E, CBli-W, CB-2, CB-3a, CB-4, CB-6a, CB-6d, CB-7, F-im, F-1p, M-2c, MUWPH, R-li, R-1m, R-l lo, T-la, T-Id, T-If, T-lh, T-Ik, T-lj i

YTRANSYTRX Transient Without Isolation A-le, A-2a, A-2c, A 2d, A-2e, A-2m, A-20, A-3a, A-3b, A-3c, A-3e, A-3g, A-4, A-5, CB-Id, CB-Ig, CB-3d, CB-3e, CB-3f, CB-Sa, CB-5b, CB-Sc. CB-6a, CB-6b, CB-6d, D-1. D-10, D-2, D-3, D4a, D-5a, D-6a, D-7, D-8, D-9, F-la, F-lb, F-In, F-lo, M-1, M ta, M-2b, M 3, M4, j

R-lb, R Ic, R-Ig, R-lh, R-Ir, RITANK, SERV, T-li

?

YLOOPXXTRX Loss of Off Site Power CB-2, CB-3a, CB-6a, R-li. R-It, T If j

YLOSSSWIRX Loss of Plant Service Water CB-le, CB-If, CB-2, CB 4, CB-6a, F-tm, F-i Ip. M-2c -

YLOSSFWTRX Loss of Feedwater A la, A lb, A-2b, A-2f, A-2k, A-2in, A-2n, A-3a, A-3d, A-3f, CB-lf, CB-2, CB-3a, CB4, CB-6a, R-It, T-la, T-lb, T-Ic, T-le, T-If, T-Ig, T-1h, T-Ik, T-1m YLOSSIATRX IAssofInstrument Air A-3d, CB-If, CB-2, CB-3a, CB4, CB-6a, R li, i:

R-lp, R-lq, R-It, T-1f, T-1h l

l YLOSSDCTRX Loss of DC Bus A-lb, A-2k, A-3d, CB-le, CB-3a, CB-3b, CB-3c, CB-3g

.,m

to U-603132 Page 16 of 28 Initiating Event Initiating Event Fire Zones Identifier' Description YLLOCAXTRX LargeIDCA None - A fise does not Directly Lead to a Large IDCA. Large LOCAs that result from Safety Valves Failing to Open are Covered byTransfers froen Other Initiating Event Trees.

YMEDLOCTRX Medium LOCA None - A fire does not Directly Lead to a Mediu n IDCA.

YSBIDCA'IRX SmallBreak LOCA None - A fire does not Directly Lead to a Small Break LOCA.

YlORVXXTRX Inadvertent Open Relief Valve None - A fire, as hw does not Directly 14ad to an Inadvert Open Rehef Valve (IORV).

IORVs that result from Safety Valves Failing to Re-Close are Covered byTransfers from Other Initinstar Event Trees.

YISLOCATRX, Inte: facing Symem LOCAs None - See Note 2.

YISLOCBTRX, YISLOCCTRX, YlSLOCDTRX Note 1: Although there are Anticipated Transient Without Scram (ATWS) and Station Blackout (SBO) event trees, there are no direct initiators for these trees. The SBO event tree is transferred to from the Loss of Off Site Power tree, and the ATWS tree is transferred to from various event trees when the scram function fails.

Note 2: There are several Interfacing System LOCAs (ISLOCA) scenarios postulated and evaluated for CPS in the internal events PRA model. A review of each of these scenarios was performed to determine if any of them could be initiated by a fire in any of the fire zones. The following conclusions were reached:

All but one ISLOCA scenario involves the failure of a high pressure side check valve in the initiating event scenario. Since fires do not result in check valves failing, these scenarios were determined to not be impacted by 6re scenarios.

The remaining ISLOCA scenario is the Shut Down Cooling ISLOCA scenario.

In this scenario, two high pressure side motor-operated valves (MOVs) must fail for the scenario to occur. During power operations with the reactor at high

. primary side pressure, the power to one of the two MOVs is physically removed by racking out its associated circuit 'oreaker. With the power removed, the MOV becomes equivalent to a manual valve, and is' not susceptible to fire induced failures.. Therefore, this scenario was also determined to not be impacted by fire scenarios.

//

~

. - -. - ~

i

' =

l Attachment I to U403132 Page 17 of 28 Once the screening analysis was completed, those fire zones that did not screen out based on Core

]

Damage Frequency (Ignition Frequency

• CCDP) were analyzed in more detail. Fire zones that did not meet the screening criteria were segmented in order to determine the effects of specific fires on cables or equipment located within a given fire zone. The impact of a fire on a particular piece of equipment or cable is a function of the ignition source, cable / equipment characteristics, and fire damage area geometry.

Fire modeling was performed on an ignition source-by-source basis and had two subdivisions:

fixed (in-situ) sources and transient sources. Fixed ignition sources are those sources that are either installed such that they are immobile (a pump for example) or by procedure or practice are always located in the same place within a fire zone. Transient ignition sources are defined as sources that have the potential to be located essentially anywhere wiinin a fire zone. To evaluate j

the effects of transient ignition sources, each fire zone was divided into segments (referred to as i

fire damage areas) based on the layout of the room, and the potential for fire propagation. To distinguish between the screening analysis and the detailed analysis, the scenarios associated with 1

the detailed analysis are referred to as fire damage area scenarios instead of fire zone scenarios,

)

l regardless of whether the scenario involves a fixed ignition source or a transient ignition source.

l The CDFs corresponding to each fire damage area scenario were ranked. The CDFs associated with the fire damage area scena<ios were reviewed to identify the top ten dominant fire damage area scenarios. It was noted that some fire zones have high cumulative CDFs because of the large i

number of fire damage area scenarios associated with the fire zone, not because of the significance of any individual fire damage area scenario. Once the top ten dominant fire damage area 4

l scenarios were identified, the cutsets associated with each of these fire damage area scenarios were ranked based on CDF (ignition frequency

• cutset probability). Those fire damage area scenarios which had at least one cutset which was in the top 25 listing of cutsets were reviewed to determine the sequence of events that led to Core Damage. Table 5-2 includes a listing of the dominant core damage sequences in terms of the area involved, the ignition source involved, and a discussion of the system-train failures leading to core damage. A listing of the top 25 core damage cutsets associated with the dominant sequences is included in Table 5-3. Table 5-3 j

includes the ignition sources, component failures, and associated Core Damage Probabilities for the top cutsets associated with the dominant sequences. Since the Core Damage Frequency 1

associated with Control Room Fires was determined using a separate methodology, no sequences associated with Control Room fires are included in Table 5-3. As can be seen in Table 5-3, none of the dominant scenarios are associated with transient ignition sources.

For the Main Control Room analysis, the CCDPs for each cabinet were calculated based on the function of the panels and Remote Shutdown Capability. Balance of Plant (BOP) cabinets were modeled assuming a simultaneous loss of Plant Service Water, Fecdwater, and Instrument Air systems as the accident initiator. Divisional cabinets were modeled assuming a transient without isolation and failure of the entire safety-related division (s) affected. Table 5-4 shows the details of the analysis associated with the MCR cabinets, including the Cabinet identifier, the number of bays within each cabinet, the divisions of equipment impacted (including Balance of Plant), the number of relays and cards in each cabinet, the calculated Ignition Frequency and CCDP for each cabinet, the Remote Shutdown Panel (RSP) Recovery applied to each scenario (where credited),

and the calculated CDF for each cabinet.

Attachmnt I c,

to11-6031.J.

Page 18 of 28 Table 5-2: Dominant Core Damage Sequences Fire Zone Discussion of System-Train Failures Resulting in Core Damage Area A-2k A Fire Imbated by Fixed igeton Source I AP95E in Fire zone A-2k Results in a Loss of a Non-Safety DC Bus. 'Ihis fire fails RCIC, LPCS, and Division 1 of RHR (RHR A).

SuW=t failures include: HPC3 is unavailable or failed, the Operators fail to recover the Non-Safety DC Bus, and Division 2 Initiaten Fails.

A-2n A Fire Imtiated by Fixed Igmuon Source 1APIIE in Fire Zone A-2n Results in a Imr of FM..a.i Transient. This fire fails Div 1 and Div 2 Automatic D%.iimuon, RCIC, and the Main Condenser Heat Sink.

In a&hten, HPCS is unavadable or faded, the Operators fail to Manually Depressurize, and the Operators fail to Recover Feedwater.

A-2n A Fire Imtiated by Fixed Igmtion Source 1 AP07EI in Fire Zone A-2n Results in a Transient With Isolatiort This fire fails Feedwater, Div 1 and Div 2 Automahc Depressurization, and RCIC.

In additen, HPCS is unavailable or failed, and the Operators fail to Manually D ou.

A-3f A Fire Imtssted by Fixed Igmtion Source 1 AP12E in Fire Zone A-3f Results in a Transient With Isolabon. This fire fails Div 1 and Div 2 Autonatic Depressunzation and RCIC.

In a&htion, HPCS is unavadable or failed, Feedwater and Condensate fait due to insufficient Makeup, and the Operators fail to Manually Depressurize.

A-3f A Fire Imtiated by Fixed Igmtion Source IDC07E in Fire Zone A-3f Results in a Loss ofInstrument Air. "Ihis fire fails Div 2 l

Suppression Pool Heat Removal and Division 2 of RHR (RHR B & C).

In addition, HPCS is unavailable or failed, RHR Train A is unavadable or faded, and LPCS is unavailable or failed.

CB-6d A Fire Imtiated in the Riser Area of Fire Zone CB-6d Results in a Transient With Isolaten. 'Ihis fire fails RCIC, HPCS, LPCS and LPCI Train A, and ShoiL Semce Water Train B.

In addition, Plant Semce Water is unavailable or faded resulting in a failure of LPCI Trains B & C, and the Operators fail to renove the internals from check valve FP-036 such that Fire Water is unavailable for injection.

M-2c A Fire Imt ated by Fixed Igmtmn Source 1AP48E or IAP49E in Fire Zone M-2c Results in a Ims of Plant Service Water.

In a&btion, Shutdown Semcc Water is unavailable or failed (resulting in a failure of all r,upported room coolers and their supported systems - RCIC, LPCI, LPCS, HPCS), and the Operators fail to remove the intemals from check valve FP-036 such that Fire Water is unavailable for iajechon

i o

Attachment I p

to U-603132

~

- Page 19 of 28 '

i Table 5-3: Top 25 Catsets Associated With Domnimant Fu* e Scenarios (ExcInding Control Roomi Scenarios)

Fire Scenario Basic Events Event Descriptions CCDP Ignition '

CDF.

Zone Frequency Contribution A-2n 1 AP11E YLOSSFWTRX Fir e Results in a Loss of Feedwater Initiator 3.755E-4 2.46E-4 9.24E-8 HPSYSTISYM HP System Down For Preventive Maintenance GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv BFEEDWRECV Operator Fails To Recover Failed Feedwater System A-2n IAPI1E YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 2.208E-4 2.46E-4 5.43E-8 HPXF314XVP Suppression Pool Suct Isol Viv Obstructed GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol VIV BFEEDWRECV Operator Fails To Recover Failed Feedwater System A-2n IAPIIE YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 7.560E-5 2.46E-4 1.86E-8 j

GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol j

Viv r

XVYO8SACLH Cooler IVYO8SA Improperly Restored From Maintenance

[

BFEEDWRECV Operator Fails To Recover Failed Feedwater System l

A-2n LAP 07EJ YTRANISTRX Fire Results in a Transient With Isolation Initiator 1.788E-3 2.05E-5 3.67E-8 HPSYSTlSYM -

HP System Down For Ib.~4e Maintenance i

GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol l

Viv A-2n 1AP07EJ YTRANISTRX Fire Results in a Transient With Isolation Initiator 1.051E-3 2.05E-5 2.15E-8 l

HPXF314XVP Suppression Pool Suct Isol Viv Obstructed

)

GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv t

h f

I l

'r,

. to U403132.

Page _20 of 28 l

Table 5-3: Top 25 Cutsets Associated With Deaniaant Fire Scenaries (Excluding C ~+rel Rooms Scenaries)

Fire Scenario Basic Events Event Descriptions CCDP.

Ignition CDF Zone Frequency Contnhtion A-2n IAPI1E YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 7.560E 5 2.46E-4 1.86E-8.

GIA013AMVW Operator Fails To Manually Open Div 2 Air Battle Isol viv XVYO8SBCIR Cooler IVYOSSB Improperly Restored From Maintenance BFEEDWRECV Operator Fails To Recover Failed Feedwater System A-2n 1 APIIE YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 7.560E-5 2.46E-4 1.86E-8 i

HPSYSTISYH HPCS Not Properly Restored From Maintenance GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv BFEEDWRECV Operator Fails To Recover Failed Feedwater System A-2n 1APlIE YLOSSFWTRX Fire Results in a Loss ofFeedwater Initiator 7.560E-5 2.46E-4 1.86E-8 HRITKCCLSH Common Cause Miscalibration Of RCIC Tank Level I

Transmitters i'

GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol VIV i

+

BFEEDWRECV Operator Fails To Recover Failed Feedwater System A-2n IAPIIE YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 7.560E-5 2.46E-4 1.86E-8 j

P3MAINTLGH HPCS Failure To Properly Restore From Maint GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv BFEEDWRECV Operator Fails To Recover Failed Feedwater System i

A-2n IAPIIE YLOSSFWTRX Fire Results in a Loss ofFeedwater Initiator 7.560E-5 2.46E-4 1.86E-8

[

HPXN056FSH Miscalibration OfHPCS Flow Transmitter GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv BFEEDWRECV Operator Fails To Recover Failed Feedwater System i

t

c, to U-603132.

F

~

Page 21 of 28 Table 5-3: Top 25 Catsets Associated With Dominant Fist Scemanios (Excluding Control Room Scenarios)

Fire Scenario Basic Events Event Descriptions CCDP Ignition CDF l

Zone Frequency Contnhition A-2n IAPIIE YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 5.292E-5 2.46E-4 1.30E-8 P3LOGICLGM HPCS Components Down For Maintenance GIA013AMVW Operatoe Fails To Manually Open Div 2 Air Bottle Isol Viv i

BFEEDWRECV Operator Fails To Recover Failed Feedwater System A-2n 1APIlE YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 5.213E-5 2.46E-4 128E-8 l

HRITKCCLSZ Common Cause Failure Of RCIC Tank Level Transmitters To Actuate i

GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv i

BFEEDWRECV Operator Fails To Recover Failed Feedwater System i

BHRITKXLSZ Failure To Recover From RCIC Storage Tank Level

{

Switch Failure j

M-2c 1AP48E YLOSSSWTRX Fire Results in a Loss of Plant Service Water Initiator 1.34E-5 9.34E-4 1.25E-8 XSX01CCCVO Common Cause Check Valve SX001 A B&C Fails To Open EIFP036CVW Operators Fail To Remove Internals From -36 Chk Viv CB-6d RISER YTRANISTRX Fire Results in a Transient With Isolation Initiator 3.859E-4 3.03E-5 1.18E-8 AREA j

WS01FABSTP Strainer / Filter lWS01FA/B Plugged EIFP036CVW Operators Fail To Remove Internals From -36 Chk Viv A-3f IDC07E YLOSSIATRX Fire Results in a Loss ofInstrument Air Initiator 1.752E-5 6.67E-4 1.17E-8 i

HPXF314XVP Suppression Pool Suct Isol Viv Obstructed DC71SIASSO Static Xfer Switch C71S001 A Fails Open l

DC71SIASWH Operator Mispositions C71S001 A Bypass Switch t

Arenchmmt I g,

to U-603132.

Page 22 of 28 Table 5-3: Top 25 Catsets Associated With Dominant Fire Scenarios (Excluding Com:rel Room Scenaries)

Fire Scenario Basic Events Event Descriptions CCDP-Ignition CDF Zone Fresp-m Contribution A-2n 1APIIE YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 4.536E-5

-2.46E-4 1.12E-8 HPXC00lMPS HPCS Pump Fails To Start GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv BFEEDWRECV Operator Fails To Recover Failed Feedwater System BHPC00lMPS Failure To Recover From Hpes Pumn Faihre To Start A-2k 1AP95E YLOSSDCTRX Fire Results in a Loss ofNon-Safety DC Bus Initiator 2.235E-5 4.92E-4 1.10E-8,

BDCBUSRECV Failure To Recover De-Energized Non-Safety Dc Bus HPSYSTISYM HP System Down For P1..mGve Maintenance PN091BLSYH Restoration Error LevelTrans N091B A-2k 1AP95E YLOSSDCTRX Fire Results in a Loss ofNon-Safety DC Bus Initiator 2.235E-5 4.92E-4 1.10E-8 BDCBUSRECV Failure To Recover De-Energized Non-Safety Dc Bus HPSYSTISYM HP System Down For F1..

Gve Maintenance PN091FLSYH Restoration Error LevelTrans N091F A-2n IAPI1E YLOSSFWTRX Fire Results in a Loss of Feedwater Initiator 4.415E-5 2.46E-4 1.09E-8 HPXF036XVP Injection IsolViv F036 Obstructed GIA013AMVW Operator Fails To Manually Open Div 2 Air Bottle Isol Viv BFEEDWRECV Operator Fails To Recover Failed Feedwater System M-2c 1AP48E YLOSSSWTRX Fire Results in a Loss of Plant Service Water Initiator 1,126E-5 9.34E-4 1.05E-8 XSX14CCMVC Common Cause WS To SX A B&C Valves Fail To Close ElFP036CVW Operators Fail To Remove Internals From -36 Chk Viv M-2c 1AP49E YLOSSSWTRX Fire Results in a Loss of Plant Service Water Initiator 1.34E-5 7.25E-4 9.72E-9 XSX01CCCVO Common Cause Check Valve SX001 A B&C Fails To Open EIFP036CVW Operators Fail To Remove Internals From -36 Chk Viv

=

Attachnwa' I r.

to U-603132.

Page 23 of 28 Table 5-3: Top 25 Cutsets Associated With Dominant Fire Scenarios (Excluding Control Room Scenados)

Fire Scenario Basic Events Event Descriptions CCDP Ignition CDF Zone Frequency Contribution A-3f -

1AP12E YTRANISTRX Fire Results in a Transient With Isolation Initiator 2.980E-5 3.17E-4 9.45E-9 HPSYSTISYM HP System Down For Preventive Maintenance FCYTANKTKL Cy Tank Level Insufficient For 24 Hr Makeup GIA012AMVW Operator Fails To Manually Opca Div 1 Air Bottle Isol Viv

[

FMCTANKTKL Inventory In The Mc Tank Insufficient For Mission Time M-2c 1AP48E YLOSSSWTRX Fire Results in a Loss of Plant Service Water Initiator 9.635E-6 9.34E-4 9.00E-9 i

HPXF314XVP Suppression Pool Suct Isol Viv Obstructed XDSPRCCGRX Common Cause Fail Div 12&3 Discharge Press Inst EIFP036CVW Operators Fail To Remove Internals From -36 Chk Vlv BSXMANSTRT Operator Fails To Manually Start SX System A-3f IDC07E YLOSSIATRX Fire Results in a Loss ofInstrument Air Initiator 1.261E-5 6.67E-4 8.41E-9 HPX314XVP Suppression Pool Suct Isol Viv Obstructed i

RE21C02MPR RHR A/LPCS Water Leg Pump Fails To Run M-2c 1AP49E YLOSSSWTRX Fire Results in a Loss of Plant Service Water Initiator 1.126E-5 7.25E-4 8.16E-9 XSX14CCMVC Common Cause WS To SX A B&C Valves Fail To Close ElFP036CVW Operators Fail To Remove Internals From -36 Chk Viv 4

s Attachment I t

to U-603132,

Page 24 of 28 Table 5-4: Control Room Fire Scenarios Cabinet Divisions Affected Relay Card Ignition CCDP RSP Cabinet Name Loading Leading Frequency Recovery CDF

1. of Dh Dk Dk BOP bays 1

2 3

P680 10 yes yes yes yes 0

70 3.80E-05 5.00E-03 1.00 1.90E-07 P663 4 yes yes yes yes 0

308 1.15E-04 1.17E-03 1.00 1.35E-07 P839 10 yes yes yes yes 174 76 7.54E-04 1.30E-04 1.00 9.815-08 P669 3 yes no no yes 81 88 3.76E-04 1.97E-04 1.00 7.41E-08 P670 3 no yes no yes 80 89 3.73E-04 1.%E-04 1.00 7.29E-05t P672 3 yes no no yes 85 91 3.94E-04 1.77E-04 1.00 6.98E-bo P671 3 no yes yes yes 85 89 3.93E-04 1.61E-04 1.00 6.32E-08 P851/852 6 yes yes no yes 143 167 6.57E-04 9.40E-05 1.00 6.17E-08 P861/862 5 yes yes no yes 139 160 6.38E-04 7.22E-05 1.00 4.60E-08 P821/822 3 no no yes yes 19 59 1.12E-04 3.21E-04 1.00 3.60E-08 P612 3 no no no yes 58 63 2.74E-04 1.30E-04 1.00 3.56E-08 P855 2 no no no yes 52 0

2.29E-04 1.30E-04 1.00 2.97E-08 P662 5 yes yes no yes 0

388 1.41E-04 1.29E-04 1.00 1.82E-08 P613 1 no no no yes 28 12 1.34E-04 1.30E-04 1.00 1.74E-08 P655 2 yes no no no 93 63 4.18E-04 4.00E-05 1.00 1.67E-08 P661 5 yes no no yes 0

423 1.52E-04 9.67E-05 1.00 1.47E-08 P614 2 no no no yes 14 24 8.05E-05 1.30E-04 1.00 1.05E-08 P845 3 no no no yes 13 0

6.87E-05 1.30E-04 1.00 8.93E-09 P827 4 no no no yes 13 0

6.87E-05 1.30E-04 1.00 8.93E-09 P632A 3 yes no no no 44 63 2.16E-04 4.00E-05 1.00 8.65E-09 P743 4 no no yes yes 1.53E-05 5.43E-04 1.00 8.29E-09 D870 10 yes yes no yes 4

0 3.17E-05 2.44E-04 1.00 7.74E-09 P601 7 yes yes yes yes 2

0 2.35E-05 3.05E-04 1.00 7.17E-09 P638 1 yes no no yes 2

0 2.35E-05 3.00E-03 0.10 7.05E-09

5 Attachmeet 1

(,

to U-603132.

Page 25 of 28 Table 5-4: Centrol Roomi Fire Scenarios Cabinet Divisions Affected Relay Card Ignities CCDP RSP Cabimet Namne Imad'ag Leading Frequency Recovery CDF

1. of.

Div Div Div BOP bays 1

2 3

P803 1 no no no yes 4

63 5.21E-05 1.30E-04 1.00 6.77E-09 P637 2 no no no yes 4

63 5.21E-05 1.30E-04 1.00 6.77E-09 P619 1 no no no yes 4

60 5.11E-05 1.30E-04 1.00 6.65E-09 P702 4 no yes yes yes 0

0 1.53E-05 4.17E-04 1.00 6.37E-09 P800m 3 yes yes yes no 9

0 5.22E-05 1.1 IE-02 0.01 5.80E-09 P654 1 no yes no no 25 63 1.38E-04 4.00E-05 1.00 5.53E-09 P708 4 no no yes yes 0

0 1.53E-05 3.54E-04 1.00 5.41E-09 P843 1 no no no yes 0

63 3.57E 1.30E-04 1.00 4.64E-09 P842 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P841 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P832 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P831 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P679 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P657 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P652 1 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P630 3 no no no yes 0

63 3.57E-05 1.30E-04 1.00 4.64E-09 P732 4 no yes no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P731 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P730 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P719 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P717 4 no yes no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P715 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P714 4 no yes no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P711 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09

a Aanchment 1 to U-603132.

Page 26 of 28 Table 5-4: Control Room Fire Scenarios Cabinet Divisions Affected Relay Card Ignition CCDP RSP Cabinet Name Loading Loading Frequency Recovery CDF

1. of Div Div Div BOP bays 1

2 3

P703 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P701 4 yes no no yes 0

0 1.53E-05 3.00E-03 0.10 4.59E-09 P642 2 no yes no no 19 63 1.14E-04 4.00E-05 1.00 4.55E-09 P664 4 no yes yes yes 0

178 7.29E-05 4.46E-05 1.00 3.25E-09 P868 1 no yes no no 10 63 7.67E-05 4.00E-05 1.00 3.07E-09 P634 2 no no no yes 0

22 2.24E-05 1.30E-04 1.00 2.91E-09 P867 1 yes no no no 9

63 7.26E-05 4.00E-05 1.00 2.91E-09 P826 1 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P744 4 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P740 4 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P709 4 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P704 4 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P656 1 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P640 2 no no no yes 0

0 1.53E-05 1.30E-04 1.00 1.99E-09 P639 1 no yes no no 2

63 4.39E-05 4.00E-05 1.00 1.76E-09 P866 1 yes no no no 0

63 3.57E-05 4.00E-05 1.00 1.43E-09 P651 1 yes no no no 0

63 3.57E-05 4.00E-05 1.00 1.43E-09 P632B 1 no yes no no 0

63 3.57E-05 4.00E-05 1.00 1.43E-09 P742 4 no yes no no 0

0 1.53E-05 4.00E-05 1.00 6.llE-10 P741 4 yes no no no 0

0 1.53E-05 4.00E-05 1.00 6.11E-10 P707 4 no yes no no 0

0 1.53E-05 4.00E-05 1.00 6.llE-10 P706 4 yes no no ne-0 0

1.53E-05 4.00E-05 1.00 6.11E-10 P800b 1 yes yes no no 32 0

1.47E-04 2.00E-07 1.00 2.93E-11 C94-P602 1 no no no yes 4

129 7.35E-05 2.00E-07 1.00 1.47E-11

^

tl Attachment I g,j to U-603132 t

v

[

Page 27 of 28 I Table 5-4; Control Rooan Fire Scenarios Cabinet Divisions Affected Relay Card Ignition CCDP RSP Cabinet f

Nanne Loading Leading Frequency Recovery CDF l

1. of Div Div Div BOP

(

bays 1

2 3

P801 2yes yes no-no 6

63 6.03E-05 2.00E-07 1.00 1.21E-11 C94-P680 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l l

C94-P606 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l J

C94-P605 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 i

C94-P604 I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11

[

C94-P603 I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l

[

C94-P601 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P645 I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-Il l

C91-P642 1 no no no -

yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P637(b)

I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P637(a)

I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P636(b)

I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P636(a)

I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P633 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-Il C91-P632 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 l

C91-P631 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P630 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P625 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l

[

C91-P621 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-Il C91-P620 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l

[

C91-P614 I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l l

C91-P613 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l l

C91-P612 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 j

C91-P609 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-Il I

I

\\

~-

t Anachment I to U-603132

' Page 28 of18 Table 5-4: Control Rooms Fire Scenarios i

Cabinet Divisions Affected Relay Card Ignition CCDP RSP Cabinet p

Nasme Imading Leading Frequency Recovery CDF i

1. of' Div Div Div BOP l

bays 1

-2 3

[

C91-P608 1 no no no-yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-Il C91-P607 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C91-P604 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l l

1 C91-P603 I no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-I l

[

C91-P601 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11

}

I C91-P600 1 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 C88-P800 3 no no no yes 0

129 5.71E-05 2.00E-07 1.00 1.14E-11 i

P865 1 no no no yes 0

63 3.57E-05 2.00E-07 1.00 7.14E-12 i

P864 1 no no no yes 0

63 3.57E-05 2.00E-Oi 1.00 7.14E-12 f

P863 1 no no no yes 0

63 3.57E-05 2.00E-07 1.00 7.14E-12 i

P678 4 yes-yes no yes 0

63 3.57E-05 2.00E-07 1.00 7.14E-12 I

P850 6 no no no yes 4

0 3.17E-05 2.00E-07 1.00 6.34E-12 P877 2 yes yes no no 0

0 1.53E-05 2.00E-07 1.00 3.06E-12 P840 1 no no no yes 0

0 1.53E-05 2.00E-07 1.00 3.06E-12 P610 1 no no no yes 0

0 1.53E-05 2.00E-07 1.00 3.06E-12 3

P607 2 no no no yes 0

0 1.53E-05 2.00E-07 1.00 3.06E-12 P600 2 no no no yes 0

0 1.53E-05 2.00E-07 1.00 3.06E-12 l

a y' s

gpt gg gi; giggggggg egggggg

,_gy7 g p:73 g 7 g:.

gg 4 ' q s e < 7 an,

1261 7934 9.46E-03 Sum 1.0E-06 I

l

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