Text

Transmittal of Final Catawba Nuclear Station Unit 1 Accident Sequence Precursor Analysis
	ML13099A352
Person / Time
Site:	Catawba
Issue date:	05/09/2013
From:	Cotton K; Plant Licensing Branch II
To:	Morris J; Duke Energy Carolinas
	Cotton K NRR/DORL/LPL2-1
References
	Download: ML13099A352 (23)
	v • d • e

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 9,2013 Mr. J. R. Morris Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 1, TRANSMITTAL OF FINAL CATAWBA NUCLEAR STATION UNIT 1 ACCIDENT SEQUENCE PRECURSOR ANALYSIS

Dear Mr. Morris:

This memorandum provides the final results of an accident sequence precursor (ASP) analysis of an operational event that occurred at Catawba Nuclear Station, Unit 1 on April 4, 2012. The analysis has a conditional core damage probability (CCDP) of less than 1 x 10-4. Therefore, the NRC is not requesting a formal review from the licensee following the ASP analysis review procedures.

The Nuclear Regulatory Commission ASP Program continues to systematically review licensee event reports (LERs) and all other event reporting information [e.g., inspection reports (IRs)] for potential precursors, and to analyze those events which have the potential to be precursors.

The complete summary of FY 2012 ASP events will be provided in the upcoming Commission paper on the status of the ASP Program and Standardized Plant Analysis Risk (SPAR) Models are due to be issued in October 2013.

Final ASP Analysis Summary. A brief summary of the final ASP analysis, including the results, is provided below.

Reactor Trip due to Faulted Reactor Coolant Pump Cable and an Error in Protective Relay Actuation Causes a Subsequent Loss of Offsite Power (April 2012) at Catawba Nuclear Station Unit 1. This event is documented in LER 413/12-001 and Inspection Reports 0500041312011009 and -010.

Event Summary. At 8:03 p.m. on April 4, 2012, Catawba, Unit 1, experienced a complete loss of offsite power (LOOP) for about five hours and 30 minutes. This condition resulted from a trip of Reactor Coolant Pump 1 D which caused a reactor trip and turbine trip. Shortly after the Unit 1 generator power circuit breakers opened, the Zone G Protective Relaying System unexpectedly actuated on an instantaneous under-frequency condition as a result of an error in the relay logic and opened the switchyard breakers thereby isolating Unit 1 from the grid and resulting in a LOOP.

Both emergency diesel generators (EDGs) automatically started and powered their respective essential busses as designed. Approximately five hours and 30 minutes after the event initiated and after confirming that the sources of the fault were cleared, offsite power was restored to Essential Bus 1 ETA

Summarv of Analvsis Results. This operational event resulted in a CCDP of 9x 10-6. The detailed ASP analysis can be found in the Enclosure.

Risk Insights. The risk of the at-power LOOP event was heavily mitigated by the availability of the ability to cross-connect offsite power to a Unit 1 essential bus via the crosstie from Unit 2.

The dominant sequence for this analysis involves the LOOP initiating event and postulated station blackout due to the failures of the plant's emergency power system (i.e., EDGs), failure of the turbine-driven auxiliary feedwater pump, and subsequent failure of operators to restore power to a Unit 1 essential bus within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

Sensitive Information. The detailed ASP analysis has been reviewed in accordance with current guidance of sensitive unclassified non-safeguards information, and it has been determined that it may be released to the public.

If you have any questions, please call me at 301-415-1438.

Sincerely,

~~

Karen Cotton, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-413 and 50-414

Enclosure:

As stated cc w/encl: Distribution via Listserv

Final Precursor Anal~sis Zmmmnl§§*'!M,tdiilik4d"t1*i'iji*b'b l "a.lijtlii.il ~tm1t¥j'iJaQi(.,,'ti41*ia4' Catawba Nuclear Station, Unit 1 Reactor Trip due to Faulted Reactor Coolant Pump Cable and an Error in Protective Relay Actuation Causes a Subsequent Loss of Offsite Power Event Date: 04/04/2012 LER: 413/12-001 IR: 50-413/12-09 and 50-413/12-10 CCDP =9x 10-6 EVENT

SUMMARY

Event Description. At 8:03 pm on April 4, 2012, Catawba Unit 1 experienced a complete loss of offsite power (LOOP) for about five hours and 30 minutes. This condition resulted from a trip of Reactor Coolant Pump (RCP) 10 which caused a reactor trip and turbine trip. Shortly after the Unit 1 generator power circuit breakers opened, the Zone G Protective Relaying System unexpectedly actuated on an instantaneous under-frequency condition as a result of an error in the relay logic and opened the switchyard breakers thereby isolating Unit 1 from the grid and resulting in a LOOP.

Both emergency diesel generators (EOGs) automatically started and powered their respective essential busses as designed. Approximately five hours and 30 minutes after the event initiated and after confirming that the sources of the fault were cleared, offsite power was restored to Essential Bus 1ETA. Additional information is provided in References 1-3.

Sequence of Key Events. The following table provides a sequence of key events. Additional information is provided in Reference 2.

April 4. 2012 20:03 With Unit 1 at 100% power, RCP 10 Phase "Y" cable faults to ground causing trip of RCP 10; automatic reactor trip on Reactor Coolant Loop 10 low flow; automatic turbine trip on reactor trip with power greater than P-8; Feeder Breaker 1 ATO supply to Essential Bus 1 ETB trips, de energizing the bus.

20:03:10 Generator Output Breakers 1A and 1 B open; EOG.1 B automatically starts and repowers Essential Bus 1 ETB.

20:03:25 Generator frequency decrease below 57.9 Hz causing instantaneous under-frequency protective relay to isolate Unit 1 offsite power causing Unit 1 LOOP and loss of power to Unit 2.

20:03:35 EOGs 1 A, 2A, and 2B start and repower their essential buses; over current alarm on EOG 2A which was out-of-service for a short period of time, but would not affect the analysis results.

20:06 RHR Pump 2A started to restore decay heat removal.

20:12 Notice of Unusual Event (NOUE) declared.

20:30 Spent Fuel Pool Cooling Pump 2B started.

21:22 Technical Support Center activated.

Enclosure 1

LER 413/12-001 22:32 Emergency Operations Facility activated.

April 5, 2012 01:29 Offsite power restored to Essential Bus 1 ETA 01:37 Offsite power restored to Essential Bus 2ETB; NOUE terminated.

01:38 EDG 1A shutdown.

01:43 EDG 2B shutdown.

02:36 Offsite power restored to Essential Bus 2ET A 02:45 EDG 2A shutdown.

05:37 Offsite power restored to Essential Bus 1 ETB.

05:41 EDG 'I B shutdown.

Simplified Electrical Drawing. Figure 1 provides a simplified drawing of the electrical distribution systems for Catawba Nuclear Station.

Red Red 1 ATE 1ETA lLXC 1ETB lLXC lETA 1lXD 1ETB Figure 1. Simplified Electrical Distribution System for Catawba Nuclear Station.

Analysis Type. The Catawba Unit 1 SPAR model, created in May 2012, was used for this event analysis. This event was modeled as a LOOP initiating event.

2

LER 413/12-001 Analysis Rules. The ASP program uses Significance Determination Process results for degraded conditions when available. However, the ASP Program performs independent analysis for initiating events.

Key Modeling Assumptions. The following modeling assumptions were determined to be significant to the modeling of this event analysis:

A reactor trip with a subsequent LOOP to both essential buses occurred.

Offsite power (via the Unit 2 crosstie) was restored to Essential Bus 1 ETA in five hours and 26 minutes after the LOOP occurred. However, power from Unit 2 was available throughout the event and operators could have restored power to a Unit 1 essential bus earlier, if needed (i.e., during a postulated station blackout). See the section on Recovery Analysis for further details.

Basic Event Probability Changes. The following initiating event frequencies and basic event probabilities were modified for this event analysis:

This analysis models the April 4, 2012 reactor trip at Catawba Unit 1 as a LOOP initiating event.

The probability of IE-LOOP (Loss of Offsite Power) was set to 1.0; all other initiating event probabilities were set to zero.

Basic Event OEP-VCF-LP-SITEAV (Site Loop [Weighted Average]) was set to FALSE and OEP-VCF-LP-SNGLAV ([Single Unit Loop (Weighted Average]) was set to TRUE.

Basic event EPS-XHE-XM-XTIE (Failure to Crosstie Power from Unit 2 during Single Unit LOOP) was set to TRUE because credit for power recovery from Unit 2 was credited in this analysis using the sequence-specific power recovery events. See the section on Recovery Analysis for further details.

The offsite power (via the Unit 2 crosstie) was recovered to the first Unit 1 essential bus in five hours and 26 minutes and both Unit 1 essential buses approximately nine hours and 34 minutes after the reactor trip and LOOP occurred; therefore, the default EDG and turbine driven auxiliary feedwater (AFW) pump mission times were changed to reflect the actual time offsite power was restored to the essential buses. Since the overall fail-to-run is made up of two separate factors, the mission times for these factors were set to the following: ZT DGN-FR-E = 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and ZT-TDP-FR-E = 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months (base case values) and ZT-DGN-FR-L =

4.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months and ZT-TDP-FR-L= 8.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months .

Recovery AnalYSis. The time required to restore offsite power to plant emergency equipment is a Significant factor in modeling the CCDP given a LOOP. The LOOP/Station Blackout (SBO) modeling within the SPAR models include various sequence-specific power recovery factors that are based on the time available to recover offsite power to prevent core damage. For a sequence involving failure of all of the cooling sources (e.g., postulated SBO with a failure of turbine-driven AFW pump), approximately 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months would be available to recover offsite power to help avoid core damage. On the other hand, sequences involving successful early inventory control and decay heat removal, but failure of long-term decay heat removal, would accommodate several hours to recover offsite power prior to core damage.

3

LER 413/12-001 In this analysis, offsite power recovery probabilities are based on:

Known information about when power was available from the Unit 2 crosstie and when power was restored to the first Unit 1 essential bus,

A determination on whether offsite power could have been restored sooner given a postulated SBO, and Estimated probabilities of failing to realign power from the Unit 2 crosstie to a Unit 1 essential bus given offsite power was available from Unit 2.

During the event, operators restored power to Unit 1 Essential Bus 1 ETA via the Unit 2 crosstie in five hours and 26 minutes after the LOOP occurred. 1 To restore offsite power to Unit 1 Essential Bus 1 ETA from Unit 2 (if needed because EDGs fail to supply the loads), operators would need to:

Determine that LOOP and subsequent (postulated) SBO occurred (with potential failures of the turbine-driven AFW pump). In addition, the operators would need to determine that offsite power was still available to Unit 2 via the Train A switchyard breakers to the 6.9 kV buses. The correct determination will lead operators to enter AP/1/A155001007, "Loss of Normal Power."

Standby Transformers SATA would need to be aligned to Unit 2 by racking-out the Unit 1 supply breakers from Bus 1 TC and racking-in the Unit 2 supply breakers from Bus 2TC. In parallel, the normal supply breakers for Essential Bus 1 ETA would be racked-out and the alternate supply breakers from SATA would be racked-in. Operators would need to develop a plan using OP/2/a/63501005, "Alternate AC Power Sources" to rack-outlrack-in the applicable breakers.

Operators would need to shed loads on Essential Bus 1 ETA per Enclosure 8 of AP/1/A155001007.

Operators would then use Enclosure 5 of AP/1/A155001007 to align alternate power to 1 ETA.

Power could have been restored within one hour from Unit 2 during a postulated station blackout (SBO).2 The SPAR-H Human Reliability Analysis Method (References 4 and 5) was used to estimate non-recovery probabilities as a function of time following restoration of offsite power to the switchyard. 3 Tables 1 and 2 provide the key qualitative information for these recovery HFEs and the performance shaping factor (PSFs) adjustments required for the quantification of the HEPs using SPAR-H.

Operators only have to restore offsite power to a single Unit 1 essential bus for successful recovery in this analysis. Since Essential Bus 1 ETB was the train with the fault on it (Rep 1 D and reports of faults on Main Transformer 1 B); it is assumed that operators would concentrate on restoring power to Essential Bus 1 ETA during a postulated Unit 1 SBO.

2 The 45-minute estimate for required time to perform the action component of the recovery of offsite power to all four essential buses for Units 1 and 2 was provided by the licensee. The staff review of this estimate determined that the basis for this estimate was reasonable. Since the 45-minute estimate assumed restoring power to the essential buses for both Units, this analysis uses 30 minutes as the approximate action time to complete power recovery to Essential Bus 1 ETA (since fewer breaker manipulations are needed).

3 The operators failing to properly diagnose the event and perform the required procedural steps to recover offsite power to Essential Bus 1 ETA are assumed to be the dominant failure contributor for recovery in this analysis.

Hardware failures are assumed to be negligible (due to their much lower failure probabilities) in this recovery analysis.

4

LER 413/12-001 of HFEs for of Power to a Unit 1 Essential Bus.

The definition for these recovery HFEs is the operators failing to restore offsite power to a Unit 1 essential bus via the Unit 2 crosstie within 1 to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months (depending on the sequence) given a postulated SBO.

Depending on postulated failures of the RCP seals (due to unavailability of seal injection/cooling), the availability of the turbine-driven AFW pump, and the time until the station batteries are depleted, operators would have between 1-24 hours to restore power via the Unit 2 crosstie to a Unit 1 essential bus prior to core uncovery.

For successful recovery, operators would have to align power from Unit 2 to an essential bus prior to core uncovery. The time available for operators to perform this action would be a minimum of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months (given the failure of the EDGs and turbine-driven AFW pump).

Essential Bus 1 ETA de-energized

Essential Bus 1 ETB de-energized

Loss of normally operating components supplied from affected bus

Affected EDG - OFF

Affected EDG breaker - OPEN

Affected sequencer not loading essential loads

1AD-11, F/4 "ZONE G LOCKOUT TRIP" - LIT AP/1/Al5500/007, "Loss of Normal Power" and OP/2/a/6350/005, "Alternate AC Power Sources."

These recovery HFEs contain sufficient diagnosis and action components.

T bl 2 SPAR HE I f fHEP f R

fP U 't 1 E f IB PSF Djagnosi~ '.Action Notes Multlpher The operators would need approximately 30 minutes to perform the action component of time to restore power via the Unit 2 crosstie to a Unit 1 essential bus. Therefore, the minimum time for diagnosis is approximately 30 minutes.

Therefore, available time for the diagnosis component for i one-hour recovery is assigned as Nominal Time (i.e., >(1).

i Available time for the diagnosis component for recoveries Time Available 1 or 0.01/1 with at least two hours is assigned as Expansive Time (i.e., xO.01; time available is >2 times nominal and >30 minutes).

Since sufficient time was available to for the action component of the recovery, the available time for the action component for the all recovery times is evaluated i as Nominal (I.e., x1). See Reference 5 for guidance on apportioning time between the diagnosis and action components of an HFE.

5

LER 413/12-001 Stress Complexity 2 f 1 2 f 1 111 1 f 1 The PSF for diagnosis stress is assigned a value of High Stress (Le., x2) due to the postulated S80.

The PSF for action stress was not determined to be a performance driver for these HFEs; and therefore, was assigned a value of Nominal (Le., x1).

The PSF for diagnosis complexity is assigned a value of Moderately Complex (Le., x2) because operators would have to deal with multiple equipment unavailabilities and the concurrent actions/multiple procedures during a postulated S80.

The PSF for action complexity was not determined to be a performance driver for these HFEs; and therefore, was assigned a value of Nominal (Le., x1).

There are three procedures (AP/11A15500/007, OP/11A163501005, and OP/11A163501002) necessary to align power to Unit 2 to restore offsite power to Unit 1.

No event information is available to warrant a change in these PSFs (for diagnosis and action) from Nominal for these HFEs.

Procedures ExperiencelTraining ErgonomicsfHMI Fitness for Duty Work Processes HEPs evaluated using SPAR-H are calculated using the following formula:

Calculated HEP = (Product of Diagnosis PSFs x 0.01) + (Product ofAction PSFs x 0.001)

Basic event OEP-XHE-XL-NR01 H (Operator Fails to Recover Offsite Power in 1 Hour) was set to 4x1 0.2.

Basic events OEP-XHE-XL-NR02H (Operator Fails to Recover Offsite Power in 2 Hours), OEP XHE-XL-NR03H (Operator Fails to Recover Offsite Power in 3 Hours). OEP-XHE-XL-NR04H (Operator Fails to Recover Offsite Power in 4 Hours). OEP-XHE-XL-NR06H (Operator Fails to Recover Offsite Power in 6 Hours). and OEP-XHE-XL-NR24H (Operator Fails to Recover Offsite Power in 24 Hours) were set to 1 x10-3.

ANAL VSIS RESULTS Conditional Core Damage Probabilities. The point estimate conditional core damage probability (CCDP) for this event is 9x1 0-6.

The Accident Sequence Precursor Program acceptance threshold is a CCDP of 1x 10-6 or the CCDP equivalent of an uncomplicated reactor trip with a non-recoverable loss of secondary plant systems (e.g., feed water and condensate), whichever is greater. This CCDP equivalent for Catawba is 2x10-6.

Dominant Sequence. The dominant accident sequence is LOOP Sequence 19-77 (CCDP =

2.3 x 10-6) which contributes 26% of the total internal events CCDP for Unit 1. Additional sequences that contribute greater than 1 % of the total internal events CCDP are provided in Appendix A.

6

LER 413/12-001 The dominant sequence is shown graphically in Figures B-1 and B-2 in Appendix B. The events and important component failures in LOOP Sequence 19-77 are:

LOOP occurs, Reactor scram succeeds, Emergency power fails,

Turbine-driven AFW fails,

Operators fail to restore offsite power within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months ,

Operators fail to recover an EDG within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months , REFERENCES

1. Catawba Nuclear Station Unit 1, "LER 413/12-001-Unit 1 Automatic Reactor Trip Due to Faulted Reactor Coolant Pump Motor Cable Resulted in Zone G Relay Lockout and Subsequent Loss of Offsite Power and Emergency Diesel Generator Automatic Start for Both Units" dated June 4,2012. (ML12157A322)

2. U.S. Nuclear Regulatory Commission, "Catawba Nuclear Station NRC Special Inspection Report 05000413/2012009," dated July 25, 2012. (ML12207A614)

3. U.S. Nuclear Regulatory Commission, "Catawba Nuclear Station NRC Special Inspection Report 05000413/2012010," dated October 11, 2012. (ML12285A100)

4. Idaho National Laboratory, NUREG/CR-6883, "The SPAR-H Human Reliability Analysis Method," August 2005 (ML051950061 ).

5. Idaho National Laboratory, "INLlEXT-10-18533, SPAR-H Step-by-Step Guidance," May 2011 (ML112060305).

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LER 413/12-001 Appendix A: Analysis Results SU!l'ma!), of Conditional E:vent Chan~~s

- :~;

Condo Nominal

. *EVcEtj"lt Dellcriptlon

,Vallj$

Va.lue EPS-XHE-XM-XTI E FAilURE TO X-TIE POWER FROM UNIT 2 DURING TRUE 1.00E-1 SINGLE UNIT LOOP IE-lOOP lOSS OF OFFSITE POWER 1.00E+0 2.84E-2 OEP-VCF-lP-SITEAV SITE lOOP (WEIGHTED AVERAGE)

False 5.79E-1 OEP-VCF-lP-SNGLA V SINGLE UNIT lOOP (WEIGHTED-AVERAGE)

True 7.41E-1 OEP-XHE-Xl-NR01 H OPERATOR FAilS TO RECOVER OFFSITE POWER IN 4.00E-2 5.46E-1 1 HOUR OEP-XHE-Xl-NR02H OPERATOR FAilS TO RECOVER OFFSITE POWER IN 1.00E-3 3.39E-1 2 HOURS OEP-XHE-Xl-NR03H OPERATOR FAilS TO RECOVER OFFSITE POWER IN 1.00E-3 2.34E-1 3 HOURS OEP-XHE-Xl-NR04H OPERATOR FAilS TO RECOVER OFFSITE POWER IN 1.00E-3 1.73E-1 4 HOURS OEP-XHE-Xl-NR06H OPERATOR FAilS TO RECOVER OFFSITE POWER IN 1.00E-3 1.10E-1 6 HOURS OEP-XHE-Xl-NR24H OPERATOR FAilS TO RECOVER OFFSITE POWER IN 1.00E-3 2.31E-2 24 HOURS ZT-DGN-FR-l DIESEL GENERATOR FAilS TO RUN 4.88E-3 2.47E-2 ZT-TDP-FR-l TURBINE DRIVEN PUMP FAilS TO RUN 1.32E-2 3.52E-2 Dominant Sequence Results Only.ite,!,sg9nt~~.~ting.. ~!{east 1*9% to th~total C99~.~re displar~d.

E:vel\\tkt~~f;J~:;~~~IJ~~Fe...* ':cc~p,*;~j~*:~i~i1trll~lo*it..i**,~.qrl~p()n lOOP 19-77 2.30E-6 26.1%

IRPS, EPS, AFW-B, OPR-01H, DGR-01H LOOP 17 1.52E-6 17.2%

IRPS, IEPS, AFW-l, FAB-l, IOPR-02H, HPR lOOP 19-75-04 1.18E-6 13.4%

IRPS, EPS, AFW-B, IOPR-01 H, IBP2, FAB LOOP 19-02 1.05E-6 12.0%

IRPS, EPS, IAFW-B, IPORV-B, ISSF-SBO, ISSF IT,OPR*24H lOOP 02-02-09 8.46E-7 9.6%

IRPS, IEPS, IAFW-l, IPORV-l, lOSC-l, IRSD-l, IBP1, BP2, IOPR*02H, IFW, HPI-l, ISSC 1, lPI lOOP 19-75-03 6.27E-7 7.1%

IRPS, EPS, AFW-B, IOPR-01H, IBP2, IFAB, HPR lOOP 19-75-10 2.89E-7 3.3%

IRPS, EPS, AFW-B, IOPR-01H, BP2, FAB lOOP 19-15-2 2.49E-7 2.8%

IRPS, EPS, IAFW-B, IPORV-B, SSF-SBO, IRSD-B, IBP1, BP2, IDC-SHED, IOPR-02H, IHPI, ISSC, lPR lOOP 19-75-09 1.52E-7 1.7%

IRPS, EPS, AFW-B, IOPR-01H, BP2, IFAB, HPR Total 8.80E*6 100.0%

Referenced Fault Trees

.f~~~;.tree~;." 1l)~.crlP1!On AFW-B AUXILIARY FEEDWATER AFW-l NO OR INSUFFICIENT AFW FLOW USING lOOP-FTF BP2 RCP SEAL STAGE 2 INTEGRITY DGR-01H OPERATOR FAilS TO RECOVER EMERGENCY DIESEL IN 1 HOUR EPS EMERGENCY POWER FAilS FAB FEED AND BLEED A-1

LER 413/12-001 Fault Tree FAB-L HPI-L HPR LOSC-L LPI LPR OPR-01H OPR-24H SSF-SBO Descripti(:m FEED AND BLEED COOLING USING LOOP-FTF FAULT TREE FLAGS HIGH PRESSURE INJECTION HIGH PRESURE RECIRC RCP SEALS FAIL FROM LACK OF COOLING USING LOOP-FTF LOW PRESSURE INJECTION LOW PRESSURE RECIRC OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 24 HOURS STANDBY SHUTOOWN FACILITY SEAL COOLING Cutset Report - LOOP 19-77 onlyitemsLcontri~~tin~at l~a~~1% to the total ar,e!di~plar~~:.

J '(;:~ap;'1if;totalo/(t **.*Cutsl:rt

,'_,,'_-__ ~__' :<'i>'-" _T'-:-<-;;

-/

2.30E-6 8.11 E-8 2

4.75E-8 3

4.34E-8 4

4.34E-8 5

3.88E-8 6

3.78E-8 7

3.52E-8 8

3.52E-8 9

3.33E-8 10 3.17E-8 11 3.17E-8 12 3.17E-8 13 3.17E-8 14 2.54E-8 15 2.54E-8 16

2. 33E-8 100 Displaying 1527 of 1527 Cut Sets.

3.52 IE-LOOP,AFW-XHE-XM-CR,EPS-FAN-CF-FRU1,EPS-XHE-XL-NR01 H.OEP-XHE XL-NR01H 2.06 IE-LOOP,AFW-TO P-FR-TOP.EPS-F AN-CF-FRU 1,EPS-XHE-XL-NR01 H, OEP-XHE XL-NR01H 1.89 IE-LOOP.AFW-XHE-XM-CR. EPS-DGN-FS-1 A. EPS-DGN-TM-1 B, EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01 H 1.89 IE-LOOP,AFW-XHE-XM-CR.EPS-DGN-FS-1 B, EPS-DGN-TM-1A,EPS-XHE-XL NR01 H.OEP-XHE-XL-NR01 H 1.69 IE-LOOP.EPS-FAN-CF-FRU1,EPS-XHE-XL-NR01 H.OEP-XHE-XL-NR01 H.SSF DGN-TM-DGN 1.64 IE-LOOP.AFW-XHE-XM-CR, EPS-OGN-CF-F SU 1,EPS-XHE-XL-NR01 H. OEP-XHE XL-NR01H 1.53 IE-LOOP,AFW-XHE-XM-CR, EPS-OGN-FR-1 A, EPS-DGN-TM-1 B,EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01 H,OEP-XHE-XX-NR01 H1 1.53 IE-LOOP,AFW-XHE-XM-CR,EPS-OGN-FR-1 B, EPS-OGN-TM-1 A,EPS-XHE-XL NR01 H,OEP"XHE-XL-NR01 H,OEP-XHE-XX-NR01 H1 1.45 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-CF-FRU 1,EPS-XHE-XL-NR01 H,OEP-XHE XL-NR01 H,OEP-XHE-XX-NR01 HO 1.38 IE-LOOP,AFW-XHE-XM-CR, EPS-OGN-TM-1A, EPS-FAN-FR-EX 1 B2, EP S-XHE-XL NR01 H,OEP-XHE-XL-NR01 H 1.38 IE-LOOP,AFW-XHE-XM-CR,EPS-OGN-TM-1 A, EP S-FAN-FR-EX 1 B 1,EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01 H 1.38 IE-LOOP,AFW-XHE-XM-CR, EPS-OGN-TM-1 B, EPS-FAN-FR-EX 1 A2, EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01 H 1.38 IE-LOOP,AFW-XHE-XM-CR, EPS-OGN-TM-1 B, EPS-FAN-FR-EX1 A 1,EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01 H 1.1 IE-LOOP,AFW-TOP-FR-TOP, EPS-OGN-FS-1 A, EPS-OGN-TM-1 B, EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01 H 1.1 IE-LOOP,AFW-TOP-FR-TOP,EPS-OGN-FS-1 B, EPS-DGN-TM-1A,EPS-XHE-XL NR01 H,OEP-XHE-XL-NR01H 1.01 IE-LOOP,EPS-FAN-CF-FRU1,EPS-XHE-XL-NR01 H, OEP-XHE-XL-NR01 H,SSF OGN-FR-OGN A-2

LER 413/12-001 Cutset Report - LOOP 17 Only items c9ntributing<atl:ast1%to the

1,*

COOp**** tQtal~~i~)Jts~t 1.52E-6 100 Displaying 1392 of 1392 Cut Sets.

2.59E-7 17.1 IE-LOOP,AFW-XHE-XM-CR,CCW-MDP-CF-FSALL,CCW-MDP-RUNA1A2,10EP XHE-XL-NR02H 2

2.59E-7 17.1 IE-LOOP,AFW-XHE-XM-CR, CCW-MDP-CF -FSALL, CCW-MDP-RUNB 1 B2,10EP XHE-XL-NR02H 3

1.52E-7 10 IE-LOOP,AFW-TDP-FR-TDP,CCW-MDP-CF-FSALL,CCW-MDP-RUNA1A2,10EP XHE-XL-NR02H 4

1.52E-7 10 IE-LOOP,AFW-TDP-FR-TOP, CCW-MDP-CF-FSALL, CCW-M DP-RUNB 1 B2,10EP XHE-XL-NR02H 5

5.62E-8 3.7 IE-LOOP,AFW-TDP-FS-TOP, CCW-MDP-CF-FSALL, CCW-MDP-RUNA 1A2,10EP XHE-XL-NR02H 6

5.62E-8 3.7 IE-LOOP,AFW-TDP-FS-TOP, CCW-MDP-CF-FSALL, CCW-MDP-RUNB 1 B2,10EP XHE-XL-NR02H 7

4.67E-8 3.07 IE-LOOP,AFW-TDP-TM-TOP, CCW-MDP-CF-FSALL, CCW-MDP-RUNA 1 A2,10EP XHE-XL-NR02H 8

4.67E-8 3.07 IE-LOOP,AFW-TO P-TM-TOP, CCW-MDP-CF-FSALL, CCW-MDP-RUNB1 B2,10EP XHE-XL-NR02H 9

2.36E-8 1.56 IE-LOOP,AFW-XHE-XM-CR,CCW-MDP-CF-FRALL,CCW-MDP-RUNA1A2,10EP XHE-XL-NR02H 10 2.36E-8 1.56 IE-LOOP,AFW-XHE-XM-CR,CCW-MDP-CF-FRALL,CCW-MDP-RUNB1B2,10EP XHE-XL-NR02H 11 2.10E-8 1.38 IE-LOOP,ACP-BAC-LP-1 ET A,AFW-XHE-XM-CR,CCW-TRN-TM-TRAI NB,IOEP XHE-XL-NR02H Cutset Report - LOOP 19-75-04 OnlyitE!rl1sc;ontril:lllting~t least 1.% to the.. total~re displayed.

.*;i cct!f?

.. ;J;rpt~I?Io i);,Cu~et*

1.18E-6 100 6.50E-8 5.53 2

3.81E-8 3.24 3

3.57E-8 3.04 4

3.11 E-8 2.64 5

2.09E-8 1.78 6

1.91 E-8 1.63 7

1.91 E-8 1.63 8

1.87E-8 1.59 9

1.71E-8 1.45 10 1.67E-8 1.42 11 1.41 E-8 1.2 Displaying 2265 of 2265 Cut Sets.

IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-TDP-FR-TOP, EPS-DGN-CF-FRU 1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-XHE-XM-CR,EPS-FAN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,IRCS-MDP-LK-BP2 IE-LOOP, EPS-DGN-CF-FRU 1,HPI-XH E-XM-FB,IOEP-XHE-XL-NR01 H,IRCS-MDP LK-BP2,SSF-DGN-TM-DGN IE-LOOP,AFW-TDP-FR-TDP,EPS-FAN-CF-FRU 1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-FS-1 B,EPS-DGN-TM-1A,HPI-XHE-XM FB,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-FS-1A,EPS-DGN-TM-1 B,HPI-XHE-XM FB,IOEP-XHE-XL -NR01 H,IRCS-MDP-LK-BP2 IE-LOOP, EPS-DGN-CF-F RU1, HPI-XHE-XM-FB,IOEP-XHE-XL-NR01 H,1RCS-MDP LK-BP2,SSF-DGN-FR-DGN IE-LOOP,EPS-FAN-CF-FRU1,H PI-XHE-XM-FB,IOEP-XHE-XL-NR01 H,IRCS-MDP LK-BP2,SSF-DGN-TM-DGN IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-CF-F SU1, HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-TOP-FS-TOP,EPS-DGN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL A-3

LER 413/12~001

""'ccoJ:"'"

ll()ta'I~.

12 1.40E-8 1.19 13 1.40E-8 1.19 14 1.40E-8 1.19 15 1.40E-8 1.19 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-TM-1 B,EPS-FAN-FR-EX 1 A2, HPI-XHE-XM FB,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-TM-1 A,EPS-FAN-FR-EX1 B 1,HPI-XHE-XM FB,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-TM-1 B, EPS-FAN-FR-EX1 A 1,HPI-XHE-XM FB,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-TM-1 A, EPS-FAN-FR-EX 1 B2,HPI-XHE-XM FB,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 Cutset Report* LOOP 19~02 0niYJt~'lJ~c~'}tri~l!tiWl~tleast 1%~~t~etotal,f!re displa'ttid.

"i.;.eCDP "TotafCJh". CutSet

~":-~~_,H_::+-,

,;? \\,

..-. -". -'\\. ". -

1.05E-6 100 Displaying 156 of 156 Cut Sets.

1,18E-7 11.2 IE-LOOP,E PS-DGN-FR-1 B, EPS-DGN-TM-1A, OEP-XHE-XL-NR24H, OEP-XHE-XX NR24H1,1SSF-SBO,lSSF-XHE-XM-SYSL T 2

1.18E-7 11.2 IE-LOOP, EPS-DGN-FR-1A, EPS-DGN-TM-1 B,OEP-XHE-XL-NR24H, OEP-XHE-XX NR24H1,1SSF-SBO,lSSF-XHE-XM-SYSL T 3

1.12E-7 10.6 IE-LOOP, EPS-DGN-CF-FRU1,OEP-XH E-XL-NR24H, OEP-XHE-XX-NR24HO,lSSF SBO,lSSF-XHE-XM-SYSL T 4

8.53E-8 8.11 IE-LOOP,EPS-DGN-FR-1A,EPS-DGN-FR-1B,OEP-XHE-XL-NR24H,OEP-XHE-XX NR24H2,1SSF-SBO,lSSF-XHE-XM-SYSL T 5

6.14E-8 5.84 IE-LOOP,EPS-FAN-CF-FRU1,OEP-XHE-XL-NR24H,ISSF-SBO,lSSF-XHE-XM SYSLT 6

3.29E-8 3.12 IE-LOOP,EPS-DGN-FS-1 B, EPS-DGN-TM-1A,OEP-XHE-XL-NR24H,ISSF SBO,lSSF-XHE-XM-SYSL T 7

3.29E-8 3.12 IE-LOOP, EPS-DGN-F S-1A, EPS-DGN-TM-1 B,OEP-XHE-XL-NR24H,ISSF SBO,lSSF-XHE-XM-SYSL T 8

2.86E-8 2.72 IE-LOOP,EPS-DGN-CF-FSU1,OEP-XHE-XL-NR24H,ISSF-SBO,lSSF-XHE-XM SYSLT 9

2.40E-8 2.28 IE-LOOP,EPS-DGN-TM-1A,EPS-FAN-FR-EX1B2,OEP-XHE-XL-NR24H,1SSF SBO,/SSF-XHE-XM-SYSL T 10 2.40E-8 2.28 IE-LOOP,EPS-DGN-TM-1B,EPS-FAN-FR-EX1A2,OEP-XHE-XL-NR24H,ISSF SBO,lSSF-XHE-XM-SYSL T 11 2.40E-8 2.28 IE-LOOP, EPS-DGN-TM-1 A,EPS-FAN-FR-EX 1 B 1,OEP-XHE-XL-NR24H,1SSF SBO,lSSF-XHE-XM-SYSL T 12 2.40E-8 2.28 IE-LOOP, EPS-DGN-TM-1 B, EPS-FAN-FR-EX1A1,OEP-XHE-XL-NR24H,ISSF SBO,lSSF-XHE-XM-SYSL T 13 2.38E-8 2.26 IE-LOOP, EPS-DGN-FR-1 B,EPS-DGN-FS-1 A, OEP-XHE-XL-NR24H, OEP-XHE-XX NR24H1,1SSF-SBO,lSSF-XHE-XM-SYSL T 14 2.38E-8 2.26 IE-LOOP, EPS-DGN-FR-1 A, EPS-DGN-FS-1 B,OEP-XHE-XL-NR24H, OEP-XHE-XX NR24H1,1SSF-SBO,lSSF-XHE-XM-SYSL T 15 1.74E-B 1.65 IE-LOOP,EPS-DGN-FR-1B,EPS-FAN-FR-EX1A1,OEP-XHE-XL-NR24H,OEP-XHE XX-NR24H 1,1SSF-SBO,lSSF-XHE-XM-SYSL T 16 1.74E-8 1.65 IE-LOOP,EPS-DGN-FR-1B,EPS-FAN-FR-EX1A2,OEP-XHE-XL-NR24H,OEP-XHE XX-NR24H1,1SSF-SBO,lSSF-XHE-XM-SYSL T 17 1.74E-8 1.65 IE-LOOP,EPS-DGN-FR-1A,EPS-FAN-FR-EX1B2,OEP-XHE-XL-NR24H,OEP-XHE XX-NR24H1,1SSF-SBO,lSSF-XHE-XM-SYSL T 18 1.74E-B 1.65 IE-LOOP, EPS-DGN-FR-1 A, EPS-F AN-FR-EX 1 B 1,OEP-XHE-XL-NR24H, OEP-XH E XX-NR24H 1,ISSF-SBO,lSSF-XHE-XM-SYSL T 19 1,67E-8 1.58 IE-LOOP,EPS-FAN-CF-FSU1,OEP-XHE-XL-NR24H,ISSF-SBO,lSSF-XHE-XM A-4

LER 413/12-001 eCDP"*

'1'otal.%

Cutsijt SYSLT 20 1.63E-8 1.55 IE-LOOP,EPS-DGN-CF-FRU12,OEP-XHE-XL-NR24H,OEP-XHE-XX-NR24HO,lSSF SBO,/SSF-XHE-XM-SYSL T 21 1.47E-8 1.4 IE-LOOP,EPS-MOV-CF-1RNMOVS,OEP-XHE-XL-NR24H'/SSF-SBO,/SSF-XHE

, XM-SYSLT 22 1.09E-8 1.04 IE-LOOP, EPS-DGN-TM-1 B,EPS-MOV-CC-1 RN232A,OEP-XHE-XL-NR24H,ISSF SBO,lSSF-XHE-XM-SYSL T 23 1.09E-8 1,04 IE-LOOP,EPS-DGN-TM-1 A,EPS-MOV-CC-1 RN292B, OEP-XHE-XL-NR24H,ISSF SBO,lSSF-XHE-XM-SYSL T Cutset Report* LOOP 02*02*09 0Qiyit~m~co~tfibW(f1~.~/ le.~~t 1.crototh~.t?tal aredisglaye1*

' 'CCDai'\\ 'tOhtlo/';'¢uts~t >::'

h

/',"

"/"

8.46E-7 100 Displaying 600 of 600 Cut Sets.

1.73E-7 20,5 IE-LOOP, CCW-MDP-CF-FSALL,CCW-MDP-RUNA 1A2,10EP-XHE-XL-NR02H,RCS MDP-LK-BP2,SSF-XHE-XM-SYSL 2

1.73E-7 20,5 IE-LOOP,CCW-MDP-CF-FSALL,CCW-MDP-RUNB1B2,10EP-XHE-XL-NRO2H,RCS MDP-LK-BP2,SSF-XHE-XM-SYSL 3

8,39E-8 9,91 IE-LOOP, CCW-MDP-CF-FSALL, CCW-MDP-RUNA 1 A2,10EP-XHE-XL-NR02H, RCS MDP-LK-BP2,SSF-PDP-FR-SYS 4

8.39E-8 9.91 IE-LOOP,CCW-MDP-CF-FSALL,CCW-MDP-RUNB1 B2,10EP-XHE-XL-NR02H,RCS MDP-LK-BP2,SSF-PDP-FR-SYS 5

2.48E-8 2,93 IE-LOOP, CCW-MDP-CF-FSALL, CCW-MDP-RUNB 1 B2,10EP-XHE-XL-NR02H, RCS MDP-LK-BP2,SSF-DGN-TM-DGN 6

2.48E-8 2,93 IE-LOOP,CCW-MDP-CF-FSALL,CCW-MDP-RUNA 1A2,10EP-XHE-XL-NR02H,RCS MDP-LK-BP2,SSF-DGN-TM-DGN 7

1.58E-8 1,86 IE-LOOP, CCW-MDP-CF-FRALL,CCW-MDP-RUNA 1A2,10EP-XHE-XL-NR02H,RCS MDP-LK-BP2,SSF-XHE-XM-SYSL 8

1.58E-8 1.86 IE-LOOP, CCW-MDP-CF-FRALL, CCW-MDP-RUNB 1 B2,/OEP-XHE-XL-NR02H, RCS MDP-LK-BP2,SSF-XHE-XM-SYSL 9

1.49E-8 1,77 IE-LOOP,CCW-MDP-CF-FSALL,CCW-MDP-RUNB1 B2,/OEP-XHE-XL-NR02H, RCS MDP-LK-BP2,SSF-DGN-FR-DGN 10 1.49E-8 1,77 IE-LOOP, CCW-MDP-CF-FSALL,CCW-MDP-RUNA 1A2,10EP-XHE-XL-NR02H,RCS MDP-LK-BP2,SSF-DGN-FR-DGN 11 1.40E-8 1,65 IE-LOOP,ACP-BAC-LP-1 ETA,CCW-TRN-TM-TRAINB,IOEP-XHE-XL-NR02H,RCS MDP-LK-BP2,SSF-XHE-XM-SYSL Cutset Report* LOOP 19-75-03 Only/fems c~~tril>Utinflatl(Jast1%t8th(J total are displayed,.

>;CG~ 'fQtaf% "Cl;d$~t 6.27E-7 100 Displaying 1765 of 1765 Cut Sets.

1,35E-8 2,15 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-RUN1A,NSR-MDP-RUN1 B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,/RCS-MDP-LK-BP2 2

1,35E-8 2,15 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-RUN1 B,NSR-MDP-RUN2A,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 3

1,35E-8 2,15 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-RUN2A,NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 4

1,35E-8 2.15 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 5

1.12E-8 1.79 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR-MDP RUN1 B,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 A-5

LER 413/12-001 CCOP

.TotaJ%. CytS~(**

6 1.12E-8 1.79 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-CF-FSALL,NSR-MDP-RUN1B,NSR-MDP RUN2A,/OEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 7

1.12E-8 1.79 IE-LOOP,AFW-XHE-XM-CR,NSR-MOP-CF-FSALL,NSR-MDP-RUN1A,NSR-MDP RUN2B,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 8

1.12E-8 1.79 IE-LOOP,AFW-XHE-XM-CR, NSR-MDP-CF-FSALL, NSR-MDP-RUN2A, NSR-MDP RUN2B,IOEP-XHE-XL -NR01 H,IRCS-MDP-LK-BP2 9

7.88E-9 1.26 IE-LOOP.AFW-TOP-FR-TDP,NSR-MDP-RUN1A,NSR-MOP-RUN1B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 10 7.88E-9 1.26 IE-LOOP,AFW-TOP-FR-TDP,NSR-MDP-RUN1B,NSR-MDP-RUN2A,NSR-MOV-CF RN2838,10EP-XH E-XL-NR01 H,IRCS-M DP-LK-BP2 11 7.BBE-9 1.26 IE-LOOP,AFW-TOP-FR-TDP,NSR-MDP-RUN2A,NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 12 7.BBE-9 1.26 IE-LOOP,AFW-TOP-FR-TOP,NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 13 6.86E-9 1.09 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-FR-1 B, EPS-DGN-TM-1 A, HPI-XHE-XM RECIRC,/OEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 14 6.86E-9 1.09 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-FR-1 A, EPS-DGN-TM-1 B,HPI-XHE-XM RECIRC,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 15 6.57E-9 1.05 IE-LOOP,AFW-TOP-FR-TOP, NSR-MDP-CF-FSALL, NSR-MDP-RUN1 B, NSR-M DP RUN2A,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 16 6.57E-9 1.05 IE-LOOP,AFW-TOP-FR-TOP,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR-MDP RUN2B,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 17 6.57E-9 1.05 IE-LOOP,AFW-TOP-FR-TOP, NSR-MDP-CF-FSALL, NSR-MDP-RUN2A, NSR-MDP RUN2B,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 18 6.57E-9 1.05 IE-LOOP,AFW-TDP-FR-TDP,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR-MDP RUN1 B,IOEP-XHE-XL-NR01 H,IRCS-MDP-LK-BP2 19 6.50E-9 104 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-CF-FRU1,HPI-XHE-XM-RECIRC,IOEP XHE-XL-NR01 H,IRCS-MDP-LK-BP2 20 6.44E-9 1.03 IE-LOOP,NSR-MDP-RUN2A,NSR-MDP-RUN2B,NSR-MOV-CF-RN2838,1OEP-XHE XL-NR01 H,IRCS-M DP-LK-BP2,SSF-DGN-TM-DGN 21 6.44E-9 1.03 IE-LOOP,NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR-MOV-CF-RN2838,1OEP-XHE XL-NRO 1 H,IRCS-MDP-LK-BP2, SSF-DGN-TM-DGN 22 6.44E-9 1.03 IE-LOOP,NSR-MDP-RUN 1A,NSR-MDP-RUN1 B, NSR-MOV-CF-RN2838,10EP-XHE XL-NR01 H,IRCS-MDP-LK-BP2,SSF-DGN-TM-DGN 23 6.44E-9 1.03 IE-LOOP,NSR-MDP-RUN1B,NSR-MDP-RUN2A,NSR-MOV-CF-RN2838,1OEP-XHE XL-NRO 1 H,IRCS-MDP-LK-BP2,SSF-DGN-TM-DGN Cutset Report - LOOP 19-75-10 OnlyiterTls co~tributinga~least 1% to the totaf are displayed.

. #: ccbpio~I%'C.~t&~(

2.89E-7 100 Displaying 1236 of 1236 Cut Sets.

1.63E-8 5.63 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,RCS-MDP-LK-BP2 2

9.52E-9 3.3 IE-LOOP,AFW-TOP-FR-TOP,EPS-DGN-CF-FRU1,HPI-XHE-XM-FB,fOEP-XHE-XL NR01 H,RCS-MDP-LK-BP2 3

8.93E-9 3.09 IE-LOOP,AFW-XHE-XM-CR,EPS-FAN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,RCS-MDP-LK-BP2 4

7.78E-9 2.69 IE-LOOP,EPS-DGN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL-NR01 H,RCS-MDP LK-BP2,SSF-DGN-TM-DGN 5

5.23E-9 1.81 IE-LOOP,AFW-TOP-FR-TOP,EPS-FAN-CF-FRU 1,HPI-XHE-XM-FB,IOEP-XHE-XL NR01 H,RCS-MDP-LK-BP2 A-6

lER 413/12-001 CCOF' Total%

cutset

~

6 4.78E-9 1.65 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-FS-1 B,E PS-DGN-TM-1 A, HPI-XHE-XM F B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 7

4.78E-9 1.65 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-FS-1 A,EPS-DGN-TM-1 B,HPI-XHE-XM FB,/OEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 8

4.68E-9 1.62 IE-LOOP, EPS-DGN-CF-FRU1,HPI-XHE-XM-FB,IOEP-XHE-XL-NR01 H,RCS-MDP LK-BP2,SSF-DGN-FR-DGN 9

4.27E-9 1.48 IE-LOOP, EPS-F AN-CF-FRU1,HPI-XHE-XM-FB,/OEP-XHE-XL-NR01 H, RCS-MDP LK-BP2,SSF-DGN-TM-DGN 10 4.16E-9 1.44 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-CF-FSU 1,HPI-XHE-XM-FBJOEP-XHE-XL NR01 H, RCS-MDP-LK-BP2 11 3.52E-9 1.22 IE-LOOP,AFW-TOP-FS-TOP,EPS-DGN-CF -FRU1,HPI-XHE-XM-FB,/OEP-XHE-XL NR01 H, RCS-MDP-LK-BP2 12 3.49E-9 1.21 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-TM-1B,EPS-FAN-FR-EX1A2,HPI-XHE-XM FB,/OEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 13 3.49E-9 1.21 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-TM-1 A, EPS-FAN-FR-EX 1 B 1,HPI-XHE-XM FB,/OEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 14 3.49E-9 1.21 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-TM-1 B,EPS-FAN-FR-EX1A 1,HPI-XHE-XM F B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 15 3.49E-9 1.21 IE-LOOP,AFW-XHE-XM-CR, EPS-DGN-TM-1A, EPS-FAN-FR-EX 1 B2,HPI-XHE-XM FB,IOEP-XHE-XL-NR01 H, RCS-MDP-LK-BP2 16 2.92 E-9 1.01 IE-LOOP,AFW-TOP-TM-TOP, EPS-DGN-CF-FRU1,HPI-XH E-XM-FB,IOEP-XHE-XL NR01 H, RCS-MDP-LK-BP2 Cutset Report - LOOP 19-15-12 O~/l'; iter:s co?tribUtinrJ..~tleast 1.% tothe total aredisplayed:

.*"COOp '. TQttlI% ;.'cutset.'

2.49E-7 100 Displaying 687 of 687 Cut Sets.

1.05E-B 4.22 IE-LOOP,/DCP-XHE-XM-DCSHED,NSR-MDP-RUN1A,NSR-MDP-RUN1 B,NSR MOV-CF-RN2838,/OEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 2

1.05E-B 422 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR MOV-CF-RN2838,10EP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 3

1.05E-B 4.22 IE-LOOP,1DCP-XHE-XM-DCSHED,NSR-MDP-RUN1 B, NSR-M DP-RUN2A, NSR MOV-CF-RN2838,10EP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 4

1.05E-B 4.22 IE-LOOP JDCP-XHE-XM-DCSHED,NSR-MDP-RUN2A, NSR-MDP-RUN2B, NSR MOV-CF-RN2838,/OEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 5

8.76E-9 3.51 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR MDP-RUN1B,/OEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 6

8.76E-9 3.51 IE-LOOP,1DCP-XHE-XM-DCSHED, NSR-MDP-CF-FSALL, NSR-M DP-RUN 1 A,NSR MDP-RUN2B,IOEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 7

8.76E-9 3.51 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-CF-FSALL,NSR-MDP-RUN2A,NSR MDP-RUN2B,IOEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 8

8.76E-9 3.51 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-CF-FSALL,NSR-MDP-RUN1B,NSR MDP-RUN2A,IOEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-XHE-XM-SYSL 9

5.36E-9 2.15 IE-LOOPJDCP-XHE-XM-DCSHED, EPS-DGN-FR-1 B,EPS-DGN-TM-1AJOEP-XHE XL-NR02H,RCS-MDP-LK-BP2,RHR-XHE-XM-RECIRC,SSF-XHE-XM-SYSL 10 5.36E-9 2.15 IE-LOOP,1DCP-XHE-XM-DCSHED,EPS-DGN-FR-1A, EPS-DGN-TM-1 BJOEP-XHE XL-NR02H, RCS-MDP-LK-BP2, RHR-XHE-XM-REC IRC,SSF-XHE-XM-SYSL 11 5.10E-9 2.04 IE-LOOP,1DC P-XHE-XM-DCSHED, NSR-MDP-RUN 1A,NSR-MDP-RUN 1 B, NSR MOV-CF-RN2838,10EP-XH E-XL-NR02H, RCS-MDP-LK-BP2,SSF-PDP-FR-SYS 12 5.10E-9 2.04 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR MOV-CF-RN2838,/OEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-PDP-FR-SYS A-7

LER 413/12-001 CCQP TQtal%

Cut$'et 13 5.10E-9 2.04 IE-LOOP,1DCP-XHE-XM-DCSHED, N SR-MDP-RUN 1 B, NSR-MDP-RUN2A,NSR MOV-CF-RN2838,10EP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-PDP-FR-SYS 14 5.10E-9 2.04

IE-LOOP,1DCP-XHE-XM-DCSHED, NSR-MDP-RUN2A, NSR-MDP-RUN2B, NSR MOV-CF-RN2838,10EP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-PDP-FR-SYS 15 5.08E-9 2.04 IE-LOOP,1DCP-XHE-XM-DCSHED, EPS-DGN-CF-FRU 1,10EP-XHE-XL NR02H,RCS-MDP-LK-BP2.RHR-XHE-XM-RECIRC,SSF-XHE-XM-SYSL 16 4.25E-9 1.7 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR MDP-RUN1 BJOEP-XHE-XL-NR02H.RCS-MDP-LK-BP2.SSF-PDP-FR-SYS 17 4.25E-9 1.7 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-CF-FSALL.NSR-MDP-RUN1A,NSR MDP-RUN2B,IOEP-XHE-XL-NR02H.RCS-MDP-LK-BP2,SSF-PDP-FR-SYS 18 4.25E-9 1.7 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-CF-FSALL,NSR-MDP-RUN2A.NSR MDP-RUN2B,IOEP-XHE-XL-NR02H.RCS-MDP-LK-BP2,SSF-PDP-FR-SYS 19 4.25E-9 1.7 IE-LOOP,IDCP-XHE-XM-DCSHED.NSR-MDP-CF-FSALL.NSR-MDP-RUN1B.NSR MDP-RUN2A,IOEP-XHE-XL-NR02H,RCS-MDP-LK-BP2,SSF-PDP-FR-SYS 20 3.87E-9 1.55 IE-LOOP.IDCP-XHE-XM-DCSHED, EPS-DG N-FR-1A.EPS-DGN-FR-1 B,IOEP-XHE XL-NR02H,RCS-MDP-LK-BP2.RHR-XHE-XM-RECIRC,SSF-XHE-XM-SYSL 21 3.68E-9 1.47 IE-LOOP,IDCP-XHE-XM-DCSHED,NSR-MDP-RUN1A.NSR-MOV-CF RN 1A2A, NSR-TRN-TM-TRAIN B,IOEP-XHE-XL-NR02H, RCS-MDP-LK-BP2, SSF XHE-XM-SYSL 22 3.68E-9 1.47 I E-LOOP,IDCP-XH E-XM-DCSHED, NSR-MDP-RUN2A, NSR-MOV-CF RN 1A2A. NSR-TRN-TM-TRAI NB,IOEP-XH E-XL-NR02H,RCS-MDP-LK-BP2,SSF XHE-XM-SYSL 23 3.57E-9 1.43 IE-LOOP,1DCP-XHE-XM-DCSHED,NSR-MDP-FS-1 A, NSR-M DP-RUN 1A, NSR-MDP TM-2A,NSR-TRN-TM-TRAINB,IOEP-XHE-XL-NR02H,RCS-MDP-LK-BP2.SSF-XHE XM-SYSL 24 2.79E-9 1.12 IE-LOOP,1DCP-XHE-XM-DCSHED, EPS-FAN-CF-FRU1,10EP-XHE-XL NR02H.RCS-MDP-LK-BP2,RHR-XHE-XM-RECIRC,SSF-XHE-XM-SYSL 25 2.60E-9 1.04 IE-LOOP,1DCP-XHE-XM-DCSHED,EP S-DGN-FR-1 B, EPS-DGN-TM-1A,IOEP-XHE XL-NR02H, RCS-MDP-LK-BP2, RHR-XHE-XM-RECIRC,SSF-PDP-FR-SYS 26 2.60E-9 1.04 IE-LOOP,1DCP-XHE-XM-DCSHED,EPS-DGN-FR-1 A, EPS-DGN-TM-1 B,IOEP-XHE XL-NR02H,RCS-MDP-LK-BP2,RHR-XHE-XM-RECIRC.SSF-PDP-FR-SYS 27 2.52E-9 1.01 IE-LOOP,1DCP-XHE-XM-DCSHED,NSR-MDP-RUN1 A, NSR-MDP-TM-2A, NSR MOV-CC-1RN28A,NSR-TRN-TM-TRAINB,IOEP-XHE-XL-NR02H,RCS-MDP-LK BP2.SSF-XHE-XM-SYSL Cutset Report - LOOP 19-75-09 Only items contributing.~tleast 1% to thetotal are displayed.

CCDP Ti;)tal'Yo CLltset 1.52E-7 100 Displaying 850 of 850 Cut Sets.

3.37E-9 2.21 IE-LOOP,AFW-XHE-XM-C R. NSR-MDP-RUN1A.NSR-MDP-RUN 1 B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 2

3.37E-9 2.21 IE-LOOP.AFW-XHE-XM-CR.NSR-MDP-RUN1B.NSR-MDP-RUN2A.NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H, RCS-M DP-LK-BP2 3

3.37E-9 2.21 IE-LOOP.AFW-XHE-XM-CR,NSR-MDP-RUN1A.NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 4

3.37E-9 2.21 IE-LOOP.AFW-XHE-XM-CR.NSR-MDP-RUN2A,NSR-MDP-RUN2B.NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H, RCS-MDP-LK-BP2 5

2.81E-9 1.84 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR-MDP RUN1 B,/OEP-XHE-XL-NR01 H, RCS-MDP-LK-BP2 6

2.81E-9 1.84 IE-LOOP.AFW-XHE-XM-CR, NSR-MDP-CF-FSALL, NSR-MDP-RUN 1 B, NSR-MDP RUN2A,IOEP-XHE-XL-NR01 H.RCS-MDP-LK-BP2 A-a

LER 413/12-001 CCD~

Total%

2.81E-9 1.84 IE-LOOP,AFW-XHE-XM-CR,NSR-MDP-CF-FSALL,NSR-MDP-RUN1A,NSR-MDP RUN2B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 8

2.81E-9 1.84 IE-LOOP.AFW-XHE-XM-CR,NSR-MDP-CF-FSALL,NSR-MDP-RUN2A,NSR-MDP RUN2B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 9

1.97E-9 1.29 IE-LOOP,AFW-TOP-FR-TOP, NSR-MDP-RUN 1A, NSR-MDP-RUN1 B, NSR-MOV-CF i RN2838,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 10 1.97E-9 1.29 IE-LOOP,AFW-TDP-FR-TDP,NSR-MDP-RUN 1 B, NSR-MDP-RUN2A, NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 11 1.97E-9 1.29 IE-LOOP,AFW-TOP-FR-TDP,NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 12 1.97E-9 1.29 IE-LOOP,AFW-TDP-FR-TDP,NSR-MDP-RUN2A,NSR-MDP-RUN2B,NSR-MOV-CF RN2838,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 13 1.72E-9 1.13 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-FR-1 B,EPS-DGN-TM-1 A,HPI-XHE-XM RECIRC,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 14 1.72E-9 1.13 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-FR-1 A,EPS-DGN-TM-1 B, HPI-XHE-XM REC I RC,10EP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 15 1.64E-9 1.08 IE-LOOP,AFW-TDP-FR-TDP, NSR-M DP-CF-FSALL, NSR-MDP-RUN 1B,NSR-MDP RUN2A,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 16 1.64E-9 1.08 IE-LOOP,AFW-TOP-FR-TDP, NSR-MDP-CF-FSALL, NSR-M DP-RUN1A,NSR-MDP RUN2B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 17 I 1.64E-9 1.08 IE-LOOP,AFW-TDP-FR-TOP, NSR-MDP-CF-FSALL, NSR-MDP-RUN2A,NSR-M DP RUN2B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 18 1.64E-9 1.08 IE-LOOP,AFW-TDP-FR-TDP, NSR-MDP-CF-FSALL,NSR-MDP-RUN 1A, NSR-MDP RUN1 B,IOEP-XHE-XL-NR01 H,RCS-MDP-LK-BP2 19 1.63E-9 1.07 IE-LOOP,AFW-XHE-XM-CR,EPS-DGN-CF-FRU1,HPI-XHE-XM-RECIRC,IOEP XHE-XL-NR01 H,RCS-MDP-LK-BP2 20 1.61E-9 1.06 IE-LOOP, NSR-MDP-RUN2A,NSR-MDP-RUN2B, NSR-MOV-CF-RN2838,10EP-XHE XL-NR01 H,RCS-MDP-LK-BP2, SSF-DGN-TM-DGN 21 1.61E-9 1.06 i IE-LOOP, NSR-M DP-RU N 1A,NSR-MDP-RUN 1 B,NSR-MOV-CF-RN2838,/OEP-XHE XL-NR01 H,RCS-MDP-LK-BP2,SSF-DGN-TM-DGN 22 1.61 E-9 1.06 IE-LOOP, NSR-MDP-RUN1A,NSR-MDP-RUN2B,NSR-MOV-CF-RN2838,1 OEP-XHE XL-NR01 H,RCS-MDP-LK-BP2,SSF-DGN-TM-DGN 23 1.61E-9 1.06 IE-LOOP, NSR-MDP-RUN1 B, NSR-M DP-RUN2A, NSR-MOV-CF-RN2838,10EP-XHE XL-NR01 H,RCS-MDP-LK-BP2,SSF-DGN-TM-DGN Referenced Events ewnt O~$crip1ic::ll1 Probability ACP-BAC-LP-1 ETA DIVISION 1A AC POWER 4160V BUS 1 ETA FAILS 3.33E-5 AFW-TDP-FR-TOP AFW TURBINE DRIVEN PUMP FAILS TO RUN (INCLUDING 1.76E-2 RECOVERY)

AFW-TDP-FS-TOP AFWTURBINE DRIVEN PUMP FAILS TO START (INCLUDING 6.49E-3 RECOVERY)

AFW-TDP-TM-TOP AFWTDP UNAVAILABLE DUE TO TIM 5.39E-3 AFW-XHE-XM-CR OPERATOR FAILS TO THROTTLE AND CONTROL AFW FLOW 3.00E-2 FROM CONTROL ROOM CCW-MDP-CF-FRALL CCW-MDP-CF-FSALL CCW-MDP-RUNA 1A2 CCW-MDP-RUNB 1 B2 CCW-TRN-TM-TRAINB CCF OF ALL CCWS TO RUN CCF OF ALL CCWS TO START FRACTION OF TIME 1A1 AND 1A2 ARE RUNNING FRACTION OF TIME 1 B 1 AND 1 B2 ARE RUNNING CCWTRAIN B UNAVAILABLE DUE TO TIM (PSA) 1.58E-6 1.73E-5 5.00E-1 5.00E-1 2.10E-2 A-9

I LER 413/12-001

~v~nt, EPS-DGN-CF-FRU1 EPS-DGN-CF-FRU12 EPS-DGN-CF-FSU1 EPS-DGN-FR-1A EPS-DGN-FR-1 B EPS-DGN-FS-1A EPS-DGN-FS-1B EPS-DGN-TM-1A EPS-DGN-TM-1 B EPS-FAN-CF-FRU 1 EPS-FAN-CF-FSU1 EPS-FAN-FR-EX1A 1 EPS-FAN-FR-EX 1 A2 EPS-FAN-FR-EX 1 B 1 EPS-FAN-FR-EX1 B2 EPS-MOV-CC-1 RN232A EPS-MOV-CC-1 RN292B EPS-MOV-CF-1 RNMOVS EPS-XHE-XL-NR01 H HPI-XHE-XM-F B HPI-XHE-XM-RECIRC IE-LOOP NSR-MDP-CF-FSALL NSR-MDP-FS-1A NSR-MDP-RUN1A NSR-MDP-RUN1 B NSR-MDP-RUN2A NSR-MDP-RUN2B NSR-MDP-TM-2A NSR-MOV-CC-1 RN28A NSR-MOV-CF-RN1A2A NSR-MOV-CF-RN2838 NSR-TRN-TM-TRAINB OEP-XHE-XL-NR01 H OEP-XHE-XL-NR24H OEP-XHE-XX-NR01 HO OEP-XHE-XX-NR01 H1 OEP-XHE-XX-NR24HO OEP-XHE-XX-NR24H1 OEP-XHE-XX-NR24H2 RCS-MDP-LK-BP2

.pe.scrf~~o~

CCF OF UNIT 1 DIESEL GENERATORS TO RUN CCF OF UNIT 1 & 2 DIESEL GENERATORS TO RUN CCF OF UNIT 1 DIESEL GENERATORS TO START DIESEL GENERATOR 1A FAILS TO RUN DIESEL GENERATOR 1B FAILS TO RUN DIESEL GENERATOR 1A FAILS TO START DIESEL GENERATOR 1B FAILS TO START DIESEL GENERATOR 1A UNAVAILABLE DUE TO TIM DIESEL GENERATOR 1B UNAVAILABLE DUE TO T/M CCF OF UNIT DIESEL GENERATOR EXHAUST FANS TO RUN (1A1/1B1)

CCF OFUNIT 1 DIESEL GENERATOR EXHAUST FANS TO START (1A1/1B1)

FAILURE OF DIESEL GENERATOR 1A FAN 1A1 TO RUN FAILURE OF DIESEL GENERATOR 1A FAN 1A2 TO RUN FAILURE OF DIESEL GENERATOR 1B FAN 1B1 TO RUN FAILURE OF DIESEL GENERATOR 1B FAN 1B2 TO RUN FAILURE OF NSRlEPS MOV RN232A TO OPEN FAILURE OF NSR/EPS MOV 1 RN292B TO OPEN CCF OF NSR/EPS MOVS RN232A AND 292B TO OPEN OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR OPERATOR FAILS TO INITIATE FEED AND BLEED COOLING OPERATOR FAILS TO START HIGH PRESSURE RECIRC LOSS OF OFFSITE POWER CCF OF ALL NSR MDPS TO START NSR MDP-1A FAILS TO START FRACTION OF TIME NSR MDP-1A IS RUNNING FRACTION OF TIME NSR MDP-1B IS RUNNING FRACTION OF TIME NSR MDP-2A IS RUNNING FRACTION OF TIME NSR MDP-2B IS RUNNING NSR MDP-2A UNAVAILABLE DUE TO T & M FAILURE OF NSR MDP-1A DISCHARGE MOV RN28A TO OPEN CCF OF TRAIN A DISCHARGE MOVS 1 RN28A & 2RN28A FAILURE OF NSR MDP DISCHARGE MOVS TO OPEN NSR TRAIN B UNAVAILABLE DUE TO T & M (PSA)

OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 24 HOURS CONVOLUTION FACTOR FOR CCF-OPR (1HR AVAIL)

CONVOLUTION FACTOR FOR 1FTR-OPR (1HR AVAIL)

CONVOLUTION FACTOR FOR CCF-OPR (24HR AVAIL)

CONVOLUTION FACTOR FOR 1FTR-OPR (24HRAVAIL)

CONVOLUTION FACTOR FOR 2FTR-OPR (24HR AVAIL)

RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING OPEN)

FAILS j:)rObabllity 1.41 E-4 2.06E-S 3.61E-S 1.04E-2 1.04E-2 2.89E-3 2.89E-3 1.43E-2 1.43E-2 7.76E-S 2.11E-S 2.11E-3 2.11E-3 2.11 E-3 2.11E-3 9.63E-4 9.63E-4 1.86E-S 8.71E-1 2.00E-2 2.00E-3 1.00E+O 1.9SE-6 1.36E-3 S.OOE-1 S.OOE-1 S.OOE-1 S.OOE-1 1.32E-2 9.63E-4 1.86E-S 2.34E-6 2.20E-2 4.00E-2 1.00E-3 2.26E-1 2.26E-1 1.00E+O 1.00E+O 1.00E+O 2.00E-1 A-10

LER 413/12-001

~cd~()~

OPERATOR FAILS TO INITIATE LOW PRESSURE RECIRC SSF-DGN-FR-DGN FAILURE OF SSF DIESEL GENERATOR TO RUN SSF-DGN-TM-DGN SSF DIESEL GENERATOR UNAVAILABLE DUE TO TIM SSF-PDP-FR-SYS FAILURE OF SSF MAKE-UP PDP TRAIN TO RUN SSF-XHE-XM-SYSL OPERATOR FAILS TO START AND ALIGN SSF DURING LOOP

~robab,iA~i¥ 2.00E-3 8.63E-3 1.43E-2 4.8SE-2 1.00E-1 A-11

LER 413/12-001 Appendix 8: Key Event Trees 8-1

LER 413/12-001 event tree.

8-2

J. Morris

- 2 Summary ofAnalvsis Results. This operational event resulted in a CCDP of 9x 10-6. The detailed ASP analysis can be found in the Enclosure.

Risk Insights. The risk of the at-power LOOP event was heavily mitigated by the availability of the ability to cross-connect offsite power to a Unit 1 essential bus via the crosstie from Unit 2.

The dominant sequence for this analysis involves the LOOP initiating event and postulated station blackout due to the failures of the plant's emergency power system (i.e., EDGs), failure of the turbine-driven auxiliary feedwater pump, and subsequent failure of operators to restore power to a Unit 1 essential bus within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

Sensitive Information. The detailed ASP analysis has been reviewed in accordance with current guidance of sensitive unclassified non-safeguards information, and it has been determined that it may be released to the public.

If you have any questions, please call me at 301-415-1438.

Sincerely, IRA!

Karen Cotton, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-413 and 50-414

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC RidsNrrDorlLpl2-1 Resource RidsNrrPMCatawba Resource LPL2-1 R/F RidsNrrDorlDpr Resource (hard copy)

RidsAcrsAcnw_MailCTR RidsNrrResDE Resource RidsRgn2MailCenter Resource Resource RidsNrrLASFigueroa Resource RidsNrrDirsltsb Resource ADAMS Accession No. ML13099A352 OFFICE NRRlLPL2-1/PM NRR/LPL2-1/LA RESIDRA NRR/LPL2-1/BC NRR/LPL2-1/PM NAME KCotton*

SFigueroa DCoe RPascarelli KCotton DATE 04/16/13 04/15/13 03/05/13 04/29/13 05/09/13

See prevIous OFFICIAL RECORD COpy

ML13099A352

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