ML15154B050

Risk Analysis to Support Response to Requests for Additional Information Regarding One Time Emergency License Amendment Request to Revise Tech Spec Section 3.8.1 to Permit Extending the Completion Time. (RAI-APLA 1)

ML15154B050
Person / Time
Site:	Cook
Issue date:	05/29/2015
From:	Heyeck J Indiana Michigan Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML15154B043	List: AEP-NRC-2015-52, Response to a Request for Additional Information Regarding the Emergency License Amendment Request to Extend the Allowed Outage Time for an Emergency Diesel Generator ML15154B048 ML15154B050
References
AEP-NRC-2015-52
Download: ML15154B050 (16)

Text

Enclosure 6 to AEP-NRC-2015-52 Risk Analysis to Support Response to Requests for Additional Information Regarding One Time Emergency License Amendment Request to revise Technical Specification Section 3.8.1 to permit extending the Completion Time. (RAI-APLA 1)

• mraN'D. C. COOK NUCLEAR PLANT E&ECTRIC PWRCALCULATION/REPORT COVER SHEET Bull []~bw Renw-denu Rev No, 0 Document No. PRA-QNT-005 []Status Change

Title:

Additional Calculation of Regulatory Guide 1.177 Risk Parameters for Potential One-Time Emergency Technical Specification Completion Time Change for Unit I AB EDG STATUS: Z Approved El Superseded El Voided Ii Information Only Document Type/Class: ED Calculation EI Report [] Class 1 0I Class 2 Z Class 3 QUALITY SYSTEM UNIT COMPUTER REVIEW METHOD:

CLASSIFICATION: CODE: NO.: MEDIA: 0 Detailed Review El Safety-Related 0I Yes El Alternate Calculation LI Non-Safety Related with NAPL I No El Other Special Requirements N N/A - Status/Class Change Only

[ Non-Safety Related Do any assumptions require later verification? U Yes 0 No If yes, Al No.

==

Description:==

See Purpose This non-design calculation is exempted by the approver from the configuration management requirements of 12-EHP-5040-DES-003 section 3.4.5.

If the Reviewer is the Preparer's supervisor, the supervisor review is needed and is approved: O N/A Supervisor's Manager's Name Title Signature Date Qualification Matrix Verification

• The responsible Engineering Supervisor/Manager approval signature also serves to signify that the qualifications of the individual(s) assigned as Preparer(s) and Reviewer(s) and Independent Design Verifier(s) were verified in the Plant Qualification Matrix.

Preparation & Review PREPARED BY: REVIEWED BY: *APPROVED BY:

Name: James M. Heyeck Stephen J. Cherba Andrew Garrett

-title: PRA Engineer PRA Engineer Manager Organization; Engineering Programs/PRA Engineering Programns/PRA. E ing Pgrams Signature:

Date: 2Z,'- -( -- o _, --. 5 El Sign-offs for additional Preparer(s) and Reviewer(s) on next page This document includes the following pages: 1-17 (17 Pages total) Page 1

Calculation No. PRA-QNT-005, Rev. 0 Page 2 I Table of Contents 1 Purpose ................................................................................................................. 5 2 Methodology ................................................................................................... 6 3 Inputs ................................................................................................................... 7 4 Assumptions .................................................................................................... 8 5 Calculations ..................................................................................................... 8 5.1 2009 Internal Events & Internal Flooding Model Items Addressed in Updated Model Pertinent to Unit 1 AB EDG CT Extension ............................................................................ 8 5.2 Clarification of Sources of Reduced Risk - Internal Events M odel ........................... 9 5.3 Fire PRA Model Items Addressed in Analysis Model Pertinent to Unit 1 AB EDG CT Ex ten sion ................................................................................................................................... 10 5.4 Clarification of Sources of Reduced Risk - Fire PRA Model .................................. 11 5.5 Risk Analysis Using the 2009 Internal Events PRA Model of Record ...................... 13 5.6 CDF and LERF Results ............................................................................................... 14 6 Conclusions .................................................................................................... 15 7 References .......................................................................................................... 16

I Calculation No. PRA-QNT-005, Rev. 0 Page 3 [

List of Tables Table 5.1 Internal Events & Internal Flooding PRA Model Issues and Resolutions for Unit I AB EDG CT E xten sion ................................................................................................ ....... ................................................... 8 Table 5.2 Internal Events Model I-EE Review Summary .................................................................................. 10 Table 5.3 Fire PRA Model Issues and Resolutions for Unit I AB EDG CT Extension ................................... 10 Table 5.4 Fire PRA H FE Review Sum m ary ......................................................................................................... 11 Table 5.5 Basic Event Settings for Baseline CDF and LERF without SDS ...................................................... 13 Table 5.5-2 -Basic Event Settings for Unit I AB EDG Failed CDF and LERF without SDS ............................. 13 Table 5.6 2009 Internal Events Model vs. Updated Internal Events Model Total CDF and LERF Results ......... 14 Table 5.6 ICCDP and 1CLERP Results for 65 Day Completion Time ............................................................ 14 List of Attachments A ttachm ent I - Files on C D ........................................................................................................................................ 17

I 1 Calculation No. PRA-QNT-005, Rev. 0 Paize 4 I1 Pa~e4 I Calculation No. PRA-ONT-005. Rev. 0 List of Abbreviations AFW Auxiliary Feedwater AMSAC ATWS Mitigating System Actuation Circuitry ATWS Anticipated Transient Without Scram CCP Centrifugal Charging Pump CDF Core Damage Frequency

-CST Condensate Storage Tank CRDM Control Rod Drive Mechanism CTS Containment Spray system CVCS Chemical and Volume Control System ECCS Emergency Core Cooling System EDG Emergency Diesel Generator EOP Emergency Operating Procedure ESFAS Engineered Safety Features Actuation System ESW Essential Service Water FW Feedwater F-V Fussell-Vesely HEP Human Error Probability 1HFE Human Failure Event HLR High Level Requirement HSS High Safety Significant ICCDP Integrated Conditional Core Damage Probability ICLERP Integrated Conditional Large Early Release Probability 1E Internal Events LERF Large Early Release Frequency LOCA Loss of Coolant Accident LSS Low Safety Significant MAAP Modular Accident Analysis Program MDAFP Motor-Driven Auxiliary Feedwater Pump MOR or MORW Model of Record MTI Maintenance Technical - Instrument and Control NRC Nuclear Regulatory Commission OOS Out of service or Unavailable PAC Plant Air Compressor PORV Power-Operated Relief Valve PRA Probabilistic Risk Assessment PDS Plant Damage State PRM Plant Response Model RAW Risk Achievement Worth RCP Reactor Coolant Pump RCS Reactor Coolant System RHR Residual Heat Removal RWST Refueling Water Storage Tank SDG Supplemental Diesel Generator SBO Station Blackout SG Steam Generator SR Supporting Requirement SSPS Solid State Protection System SI Safety Injection SIP Safety Injection Pump TDAFP Turbine-Driven Auxiliary Feedwater Pump TS Technical Specification

I Calculation No. PRA-QNT-005, Rev. 0 Page 5 1 Purpose This calculation provides clarifications on changes made to the 2009 PRA Model of Record and the Fire PRA Model of record in support of the Unit I AB EDG one time completion time extension. This information is intended to provide a response to the NRC's Request for Additional Information regarding the updated, but not yet peer reviewed Internal Events PRA model. It also provides clarification on items that were updated following the preliminary risk assessment in both the updated Internal Events and Fire PRA model.

Page 6 II Calculation No. PRA-QNT-005, Rev. Rev. 0 Page 6 2 Methodology The PRA risk impact of operation with Unit I AB EDG unavailable was estimated using an application specific updated WinNUPRA PRA Model (Input 3.1) and an updated Fire PRA model (Input 3.2), modified for this application as described in Reference 7.17. Since the updated Internal Events model has not yet been peer reviewed, this calculation provides results fi'om the 2009 Internal Events PRA Model of Record, for comparison purpose with the updated model. Regulatory Guide 1.177 (Reference 7.12) risk parameters are calculated using the following general equations:

ACDF = CDFi,, - CDFise where CDFinjst = the Unit I CDF value when only the Unit I AB EDG is unavailable, with appropriate allowances for the Unit 2-PAC & I W-MDAFP OOS time and the operation and maintenance restrictions described below (Assumption 4.1) are in place CDFb . the Unit 1 "base case" zero maintenance CDF value (with the exceptions shown in Assumption 4.1).

ALERF = LERFe,,. - LERFb 1Sc where LERFi,, = the Unit 1 LERF value when only the Unit I AB EDG is unavailable, with an appropriate allowance for the Unit 2-PAC & IW-MDAFP OOS time, and the operation and maintenance restrictions described below (Assumption 4.1) are in place LERFnve = the Unit I "base case" zero maintenance LERF value (with the exceptions shown in Assumption 4.1).

ICCDP = (ACDF)*(Duration (days) / 365 days/year)

ICLERP = (ALERF)*(Duration (days) /365 days/year)

Consistent with the cases developed in Section 2 of Reference 7.17, two quantification cases are provided for the 2009 Internal Events model.

1. A baseline CDF and LERF value with zero maintenance other than the exceptions listed in Assumption 4.1, without credit for the SDS.

2. CDF and LERF values with the Unit I AB EDG failed, with zero maintenance other than the exceptions listed in Assumption 4.1, without credit for the SDS

I Calculation No. PRA-QNT-005, Rev. 0 Page 7 3 Inputs 3.1 The 2009 WinNUPRA model of record (Reference 7. 1) is currently undergoing a fill model update. Results are provided firom the 2009 model in this calculation, and are provided for comparison to the updated model documented in Reference 7.17.

3.2 The Fire PRA model of record (Reference 7.2) was changed for this application as described in Reference 7.17. The results firom Reference 7.17 are used in this calculation.

I Calculation No. PRA-QNT-005, Rev. 0 Page 8 1 4 Assumptions 4.1 The average PRA model test and maintenance factors for the following equipment are adjusted to match the out of service durations during the Unit 1 AB EDG unavailability:

• The Unit I West MDAFP was unavailable for approximately 28 hours3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br />. The test and maintenance term is therefore adjusted to 28 Irs/ (14 days

• 24 Ir's). This conservatively accounts for 28 hours3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> of unavailability during the onethne extended EDG unavailability window.

" The Unit 2 PAC was unavailable for approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />. The test and maintenance term is therefore adjusted to 14 hour1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />s/(14 days

• 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />). This conservatively accounts for 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> of unavailability during the onetime extended EDG unavailability window.

o The Unit I Middle Heater Drain Pump remained out of service for the majority of the EDG unavailability. This pump is not modeled in the Internal Events or Fire PRA, o Required surveillance runs with short-duration (-15 rains)unavailabilities are not considered. This includes surveillance tests on other EDGs to prove that they remain operable. For EDG runs, multiple equipment operators are stationed at the EDG being tested, such that the EDG can be restored in short order.

4.2 All previous assumptions listed in Reference 7.17 are used in this analysis, with the exception of the ESW crosstie configuration, since no flag settings exist in the 2009 Internal Events model to account for this configuration. This is judged to have an insignificant impact on the overall results, for the same reasons as Assumption 4.7 in Reference 7.17 for the Fire PRA.

5 Calculations 5.1 2009 Internal Events & Internal Flooding Model Items Addressed in Updated Model Pertinent to Unit 1 AB EDG CT Extension The 2009 Internal Events & Internal Flooding PRA Model contains shortcomings that have the potential to impact the Unit I AB EDG Completion Time extension. The shortcomings, their resolution, and their impact to the.

assessment is provided in the table below.

Table 5.1 Internal Events & Internal Flooding PRA Model Issues and Resolutions for Unit I AB EDG CT Extension

-2609 Model of-Record Identified Issue E Re.oi*-ioni Updated Model Average test and maintenance values were None. The test and maintenance Test and Maintenance values incorrectly squared due to a misunderstanding of configuration of the plant is known were adjusted back to their the conditional probabilities involved with for the risk analysis. original values, and updated with support system initiating events, the latest plant specific data.

ESW and CCW pump recovery tenms were Small. Dual Unit SBO sequences Pump repair/recovery is no applied in internal flooding and dual unit SBO are low probability and have a small longer credited for Internal sequences in which pump repair was unlikely, impact on the assessment Flooding or Dual Unit SBO

Pave Pg 9 1 I Calculation No. PRA-ONT-005. Rev. 0

.2009 Model of Record Identified"Issue Impact to . AR EDG CT Resolution in Updated Mode.

Extension No safety train alignment was considered for the SDGs. The SDGs are procedurally directed to be Safety Train alignment for the aligned to a single safety train on one unit. Small. Dual Unit SBO sequences SDGs was added. This makes Although crews would be expected to re-align are low probability and have a small the updated model SBO them to the alternate train if the first train incurred impact on the assessment contributions higher for the random equipment failures, no direct procedural SDGs.

guidance exists to direct this consideration.

A reduction factor was incorrectly used for Significant Impact to the total support system initiating events to reduce contribution of common cause terms. T[his the Internal Itra Events vnsCF CDF, butu not o a cotreduction ofator don eusue thecomThisignificant on impact to this Reduction factor was removed.

reduction factor was used to ensure the cohnilon assessment. Support system This significantly raises the CDF cause. failure only occured during the technical initiating events do not challenge and LERF contribution firom specification allowed outage times during the offsite power availability and thus Loss of CCW and ESW in the year. Since common cause failure factors already the unavailability of a single EDG updated model.

include the consideration of the failures occurring does not significantly impact the within a short time period of each other, this assessment.

reduction factor is unnecessary.

The WOG 2000 RCP Seal LOCA model was not MAAP analyses have been Moderate. Plant Specific MAAP performed for SBO and updated filly incorporated. SBO offsite power recovery analysis provides a better realistic offsite power recovery times (CNU) probabilities ra than being justified by estimate of offsite power recovery were used. This generally MAAP analysesi times. reduces the SBO contributions in the updated model.

Tile amount of sequences on event trees and the None. Thle quantification issues Event trees were simplified. No total number of event trees were unnecessarily only impacted processing time and overall effect on the updated complicated leading to quantification issues, had no hipact on results, model.

A full data update was Initiating event and component data is sourced Moderate. Newer data is more performed for the model update.

from older data sources and out of date. representative of the current Component data generally operating plant. improved, so this will reduce the contributions across the model.

Very Small. Internal Flooding does Internal Events HFEs were Internal Flooding initiating events contained not challenge offsite power updated to reflect correct 1EPs.

simplified HFEs for isolation of the break which availability and thus the Minor change in overall flood require updating. unavailability of a single EDG has a contribution.

minor impact on internal flooding.

5.2 Clarification of Sources of Reduced Risk - Internal Events Model Several HFEs related to offsite power were reviewed in the updated Internal Events model as part of the risk assessment. The -FEs which resulted in the majority of the CDF reduction fiom the preliminary assessment to the final assessment are discussed below:

I Calculation No. PRA-QNT-005, Rev. 0 Calclaton N. PA-QN-00, Re. 0Pave 10-1 Pa*e Table 5.2 Internal Events Model HFE Review Summary Original~ uiae WIE, Dscription Assessed Bavalufor-change HEEP value Execution stress should not be high as assumed in the HRA due to large time to "OperatorFails toppeform perform actions and ease of action.

I EXE-RCCHE e 2.8E-2 2.96E-04 Added a recovery step in the execution.

RCS cooldown after SBO Procedure step requires operators to check SG pressure. This can be used as recovely in the HRA analysis.

Changed time window to 1.62 hrs based on core uncovery time fi'om MAAP 0A-EP-TBUS--HE Operator fails to align 4.14E-2 1.39E-02 Case LI 33d (Reference 7.7). Reduced SDGs to Safety Bus stress level to low because of high SPAR-H ratio.

Dependent HIFE The listed actions to not have a conunon Combination of 1 Th.ite.ciost.othv.ac.o COMBO 41 EXE-RCCiniE andoA-EP-TBUJS---HE 4.14E-2 1.24E-04 cognitive event (different cues). They are sequential actions:

Operator fails to fully open CCW to RHR Heat Decreased level of dependency to low IC------ALIGNHE Exchanger valves after 5.2E-3 2.60E-03 due to high available time for action.

ECCS recirculation switchover 5.3 Fire PRA Model Items Addressed in Analysis Model Pertinent to Unit I AB EDG CT Extension The Fire PRA Model of Record contains shortcomings that have the potential to impact the Unit I AB EDG Completion Time extension. The shortcomings, their resolution, and their impact to tile assessment is provided in the table below.

Table 5.3 Fire PRA Model Issues and Resolutions for Unit 1 AB EDG CT Extension Fire PRA.Model Identified Issue Imipact to i EDG CT:ixtension AB Resolution foi- RishkAssessment The Fire PRA reduced the success criteria for AFW from supplying 2 of 4 SGs to 1 of 4 SGs. This reduction requires containment spray to be Non-conservative success criteria for available (References 7.6 and 7.7) to AFW would have a moderate and non- This is conrected in the Fire PRA model prevent containment failure since conservative impact on the risk used for this application.

insufficient containment heat removal is assessment.

provided by one SG. This is corrected in the Fhre PRA model used for this application.

I Calculation No. PRA-QNT-005, Rev. 0 I Calculation No. PRA-ONT-005. Rev. 0 page 11 III Page I1 Fire PRA Model Identified Issue Impact to 1 ABR EDG CT Extensioni Resolution for. Risk Assessmnent An HFE was credited in the Fire PRA to re-power the Hydrogen Igniters after For this application, there is increased fires which left all the busses faulted on The value of the frequency weighted the fire affected unit. This action takes average f changesequen them odelithe Unit I AB EDG is not available.

3.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> lto to complete hoursfie complthe and it was tandsitio weidtas average HEP changes configuration when the model does, particularly if fire- Therefore, t tg ha risk mitigating lent oe action upyscis taken identified late in the transition period that induced SBO becomes more to stageac alternate power supply such the time to core damage could be as little significant. that the action can be completed within the as 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> in some sequences (such as 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> time window. No adjustment is AFW failure). The HEP was averaged in made to the HIEP on the basis of this action the final model to account for this.

The fire-induced SBO fault tree (I SBOINIT.LGC) was noted to contain Since this application increases the RCS inventory makeup via the CVCS an en'or. Successful operation of the likelihood of an SBO, this results in an crosstie was added to this event. Alternate TDAFP constituted success of the top increase in both the base model and the success path based on MAAP analysis gate, despite the fact that an RCP Seal application results. included a RCS cooldown.

LOCA would occur due to the blackout.

5.4 Clarification of Sources of Reduced Risk - Fire PRA Model In the Fire PRA model of record, the 480 gpm/pump Seal LOCA could not be mitigated by the CVCS crosstie based on MAAP analyses (Reference 7.7). This placed a significant emphasis on the HFE to trip the RCPs within 8 minutes (I -----CCW-RCPHIEF). No RCS cooldown was credited in the model of record analysis, even though a cooldown is directed in the Emergency Remote Shutdown procedure (Reference 7.14) and in the Post-LOCA cooldown and depressurization procedure (Reference 7.16). For this risk assessment it was desired to show that there was significant conservatism in the importance of tripping the RCPs. The MAAP analysis was performed in Reference 7.17, Section 5.2, and shows successful mitigation of the 480 gpm/pump RCP seal LOCA with the cooldown credited. This significantly reduced the risk associated with tripping the RCPs.

In addition to the credit for performing an RCS cooldown, the HFEs in the table below were reviewed. In particular, 1ASD-SBONOTDPOMA was reviewed because it contributed the majority of the preliminary delta risk. After review and operator interview, this HFEs were re-evaluated in the HRA calculator at a reduced stress level, resulting in a reduction of the HEP. These changes, in combination with the credited cooldown provided the risk decrease from the preliminary delta risk valuesdiscussed with NRC.

Table 5.4 Fire PRA HFE Review Summary Original Updated H1E 'Description Asslessed, 'UEP Basis for Change ITEPivalue V.al!e' HFE will retain the value of 4.9E-2 and be used Operator Fails to Crosstie AFW ONLY for scenarios in which the fire occurs lASD- and CVCS per Emergency inside the main control room, and stress is Remote Shutdown (Reference 4.9E-2 4.9E-2 expected to be high. Although, the HEP value in 7.14) for fires that occur in the the HRA Calculator is 1.33E-02. This value was Main Control Room left at 4.9E-2 for conservatism in the final NFPA 805 model of record.

I Calculation No. PRA-QNT-005, Rev. 0 Pap-e 12 1 original Updated OEDsription Assessed H-EP Basis for Chang HEPv.alue Value....... ..... e New HFE.

HFE will model what IASD-SBONOTDPOMA used to for scenarios in which the fire occurs outside the main control room, and stress is expected to be moderate.

The original EEP assessment foa Operator Fails to Crosstie AFW l ASD-SBONOTDPOMA is very conservative in 1FSBO--XTJE- and CVCS per Emergency that a High Operator stress level has been Remote Shutdown (Reference 4.9E-2 5.3E-03 assigned by default generating a high HEP value.

7.14), for fires that do not occur However, since the action is practiced every two in the Main Control Room years, the plant should respond as expected (i.e.,

operators have the plant under control and are familiar and comfortable with the actions and procedures required, workload might be high, but PSFs should be optimal. This was confirmed by operators on phone interview (5/26/2015),

therefore a moderate stress level is selected.

New HFE.

lIFE will model a 14F/hr cooldown per OHP-Operator Fails to initiate RCS 4025-001-00 1, step 25 given success of Cooldown after success of 1FSBO--XTIE-OMA using the same time I FSBO---RCC- CVCS and AFW crosstie per N/A 6.58E-04 window, based on new MAAP analysis.

OMA Emergency Remote Shutdown Execution Time for operator action is 15 (Reference 7.14) minutes, confirmed by operators. Moderate stress level assumed based on operator phone Interview discussed above.

Removed firom the model and superseded by I FSBO---RCC-OMA, since the cooldown is 1B-RV-- Operator fails to manually open 1.3E-2 N/A credited for fire-induced SBO only, where MIRV2X3HEF SG PORVs. CVCS and AFW crosstie must first be successful.

HeLEP agreed upon between DC Cook and the CCW- Operator Fails to Locally Trip 4.80E-03 4.80E-03 NRC and cannot be changed. If stress reduced, RCPHEF RCPs REP = -2E-03

1i Calculation 1

No. PRA-QNT-005, Rev. 00Pg CacltonN.PAQN-0.Rv.

Pap-e 13 1 13i 5.5 Risk Analysis Using the 2009 Internal Events PRA Model of Record Two cases of the 2009 ]ntfernal Events PRA Model of Record are run consistent with the cases developed in Section 2, and Reference 7.17. The Unit I West MDAFP and Unit 2 Plant Air Compressor unavailability is taken fiom Assumption 4.1. These cases are:

1. A baseline CDF and LERF value with zero maintenance other than the exceptions listed in Assumption 4.1, without credit for the SDS. For this case, the following basic event modifications are made:

Table 5.5 Basic Event Settings for Baseline CDF and LERF Component Basic Event Probability Unit I West MDAFP IDBPM---PP3WTM 8.333E-2 Unit 2 Plant Air Compressor 2X-CM---OME4TM 4.167E-2 All other Test or Maintenance Events Basic Events ending in "TM" 0

2. CDF and LERF values withl the Unit I AB EDG failed, with zero maintenance other than the exceptions listed in Assumption 4.1, without credit for the SDS. For this case, the following basic event modifications are made:

Table 5.5 Basic Event Settings for Unit I AB EDG Failed CDF and LERF Component Basic Event Probability Unit 1 AB EDG 1SBDG----DGABFR 1 Unit I West MDAFP IDBPM ----PP3WTM 8.333E-2 Unit 2 Plant Air Compressor 2X-CM---OME41TM 4.167E-2 All other Test or Maintenance Events Basic Events ending in "TM" 0

[ Calculation No. PRA-QNT-005, Rev. 0 Page 141 5.6 CDF and LERF Results The CDF and LERF results fi-om each case are shown below in Table 5.6-1. The ICCDP and ICLERP calculations are shown below in Table 5.6-2. ICCDP and ICLERP are calculated assuming a 65 day completion time, using the equations in Section 2. Updated Internal Events and Fire PRA values are obtained from Reference 7.17.

Table 5.6 2009 Internal Events Model vs. Updated Internal Events Model Total CDF and LERF Results h.i.terp.al *Events DF InternalE*viets LERF Internial ie its CDF ILn*te vlEvents LERF Case ,20~09 Model .2009 Model> Updated Model < -Updated Model

/r >/r/Yr) Oir.

Basecase 1.412E-05 2.867E-06 1.268E-04 4.237E-06 I AB EDG Failed 1.963E-05 3.454E-06 1,304E-04 5.119E-06 Table 5.6 ICCDP and ICLERP Results for 65 Day Completion Time Case *. DeltCDF (ij! Delt ".(LtFye) :'ICCDP.. JCLERP 2009 Internal Events 5.51E-06 5.87E-07 9.81 E-07 1.05E-07 Updated Internal Events 3.60E-06 8.82E-07 6.41E-07 1.57E-07 Fire PRA 1.9613-05 7.97E-07 3.49E-06 1.42E-07 Total (2009 Internal Events & Fire PRA) 2.5 1E-05 1.38E-06 4.47E-06 2.46E-07 Total (Updated Internal Events & Fire PRA) 2.32E-05 2.27E-06 4.13E-06 4.04E-07

I Calculation No. PRA-QNT-005, Rev. 0 Page 15 6 Conclusions The 2009 Internal Events PRA model provides a slightly larger estimate of lCCDP and a 50% smaller estimate of ICLERP than the updated Internal Events model. Using the 2009 Model of Record and the Fire PRA, the calculated values of4.47E-06 ICCDP and 2.46E--7 ICLERP are within the Regulatory Guide 1.177 acceptance guidelines of less than IE-5 ICCDP and IE-6 ICLERP for one time TS completion time changes, given a total TS completion time of 65 days (Reference 7.12). This one-time TS completion time change is therefore considered acceptable.