ML15149A510

Final ASP Analysis Millstone 2 3 (LER 336-14-006)

ML15149A510
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Site:	Millstone
Issue date:	06/09/2015
From:	Christopher Hunter NRC/RES/DRA
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Hunter Chris 301-251-7575
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IR 2014011
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Text

Enclosure 1

Final Precursor Analysis Accident Sequence Precursor Program - Office of Nuclear Regulatory Research Millstone Power Station Units 2 and 3 Ground Fault during Line Maintenance Causes Loss of Offsite Power to Both Units Event Date: 5/25/2014 LER: 336/14-006 IR: 50-336/14-11 CCDPs = 1x10-5 (Unit 2) 2x10-5 (Unit 3)

Plant Type: Pressurized-Water Reactors (PWRs)

Combustion Engineering with a Large Dry Containment (Unit 2)

Westinghouse 4-Loop with Sub-Atmospheric Containment (Unit 3)

Plant Operating Mode (Reactor Power Level): Mode 1 (100% Reactor Power, Both Units)

Analyst: Christopher Hunter Reviewer: Song-hua Shen Contributors: N/A EXECUTIVE

SUMMARY

At 7:01 a.m. on May 25, 2014, with Millstone Power Station Units 2 and 3 operating at 100%

reactor power, a total loss of offsite power (LOOP) occurred. The cause of the LOOP was a ground fault on one of the three offsite power lines with another line out for maintenance. The third line tripped on over-current because it was not capable of supporting the full power output for the site. Both units experienced a turbine trip on power to load imbalance followed by an automatic reactor trip. Both units' safety-related emergency diesel generators (EDGs) automatically started and supplied power to their respective safety busses. As designed, the motor-driven auxiliary feedwater (AFW) pumps automatically started for Unit 2 and all AFW pumps automatically started for Unit 3. Offsite power was restored to at least one safety bus at each unit by approximately 10:30 a.m. and fully restored at 12:56 p.m. on May 25, 2014.

According to the risk analysis modeling assumptions used in this Accident Sequence Precursor (ASP) analysis, the most likely core damage sequence for Unit 2 is a non-recoverable LOOP and subsequent station blackout (SBO) due to postulated failures of all EDGs (including the SBO diesel generator), the failure of the turbine-driven AFW pump, and the failure to restore power to a safety bus within one hour. This accident sequence accounts for approximately 67%

of the event conditional core damage probability (CCDP) for Unit 2.

For Unit 3, the most likely core damage sequence is non-recoverable LOOP and subsequent SBO due to postulated failures of both Unit 3 EDGs. Operators successfully aligned the SBO diesel generator to one of the Unit 3s safety buses; however, the operators do not have sufficient time to perform this action to prevent a challenge to the integrity of reactor coolant pump (RCP) seals (due to lack of seal injection/cooling) and subsequent loss-of-coolant accident (LOCA) occurs. AFW and high-pressure injection (HPI) are successful, but failure of high-pressure recirculation leads to core damage. This accident sequence accounts for approximately 23% of the event CCDP for Unit 3.

In general, these results are consistent with at-power LOOP events previously analyzed by the ASP Program at other PWRs.

LER 336/14-006 2

EVENT DETAILS Event Description. At 7:01 a.m. on May 25, 2014, with Millstone Power Station Units 2 and 3 operating at 100% reactor power, a total LOOP occurred. Both units experienced a turbine trip on power to load imbalance followed by an automatic reactor trip. Both units' safety-related EDGs automatically started and supplied power to their respective safety busses. As designed, the motor-driven AFW pumps automatically started for Unit 2 and all AFW pumps automatically started for Unit 3.

The Millstone staff declared a Notice of Unusual Event (NOUE) for both units at 7:15 a.m. due to a LOOP for greater than 15 minutes. Offsite power was restored to at least one safety bus at each unit by approximately 10:30 a.m. and fully restored at 12:56 p.m. on May 25, 2014. The NOUE was exited at 2:14 p.m. on May 25, 2014.

Additional information is provided in Reference 1 (licensee event report) and Reference 2 (inspection report).

Cause. Prior to the event, the station had one offsite line out-of-service (Line 371) for maintenance. A suspected ground fault on the grid in the Northeast Utilities Card substation caused the loss of offsite Line 383. Line 310 tripped on instantaneous ground over current, which was unexpected. The final line (Line 348) tripped on over-current when both units attempted to feed the full power output of both Millstone units through the single remaining line (Line 348).

Additional Event Information. The following event details are provided as additional information about the event. This additional information was not factored in the modeling of this analysis due to the negligible risk impact.

Unit 2 experienced a water hammer in the condensate polishing facility during the event.

This was entered into licensees corrective action program. The condensate polishing facility is not risk significant; therefore, the system is not modeled in the Millstone Unit 2 Standardized Plant Analysis Risk (SPAR) Model. In addition, the condenser heat sink including feedwater condensate systems are assumed to be unavailable during a LOOP.

The Unit 3 reactor trip was affected by a loss of air when the Instrument Air Compressor 13 failed to start. The loss of instrument air affected head vent letdown alignment. After unsuccessful attempts to align the head vent to the volume control tank, letdown was returned to the pressurizer relief tank (PRT) and the PRT rupture disk burst approximately 20 minutes later. Normal charging and letdown was subsequently restored, which resulted in lifting a relief valve in the letdown line. This relief valve discharged to the primary drains transfer tank (PDTT). As a result, a PDTT high level alarm was received and normal charging and letdown was isolated nine minutes later. Instrument air is not safety-related and is not currently modeled in the Millstone Unit 3 SPAR model. However, operators manually cycled the power operated relief valves (PORVs) to control RCS pressure. The demand of the PORVs and their potential failure to reclose after demand is modeled in Unit 3 analysis (see Key Modeling Assumptions for Unit 3).

LER 336/14-006 3

MODELING ASSUMPTIONS Analysis Type. The Millstone Unit 2 SPAR Model Revision 8.17 (created in March 2011) and Millstone Unit 3 SPAR Model Revision 8.20 (created in March 2012), were used for the analyses of this event. This event was modeled as a grid-related LOOP initiating event for both units.

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 for Both Units. The following modeling assumptions were determined to be significant to the modeling of the event analyses for both units:

The analyses model the May 25, 2014, dual-unit reactor trip at Millstone Power Station as grid-related LOOP initiating events.

The probability of grid-related LOOP (IE-LOOPGR) was set to 1.0; all other initiating event probabilities were set to zero.

Basic Event LOOP-DUAL-UNIT (Dual Unit LOOP) was set to TRUE. In addition, Basic Event LOOP-SNGL-UNIT (Single Unit LOOP) was set to FALSE.

To adjust the potential for each unit needing the SBO diesel generator, the combined failure probability of each units dedicated EDGs was calculated for a 3-hour mission time. The calculated failure probability of 6.8x10-4 was used for Basic Events EPS-DGN-FC-UNIT2 (SBO Diesel Generator Aligned to Unit 2) and EPS-DGN-FC-UNIT3 (SBO Diesel Generator Aligned to Unit 3).

Offsite Power Recovery. The time required to restore offsite power to plant emergency equipment is a significant factor in modeling the CCDP given a LOOP. The LOOP/SBO modeling within the SPAR models includes 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 one hour would be available to recover offsite power to avoid core damage. Sequences involving successful early inventory control and decay heat removal, but subsequent failure of RCP seals resulting in a LOCA or the failure of long-term decay heat removal, would give operators additional time to recover offsite power prior to core damage.

The key offsite power recovery times for Millstone Unit 2 that are modeled within the SPAR model are:

1 HourA LOOP and subsequent SBO with failure of all turbine-driven AFW pump, failure of a PORV(s) to reclose resulting in a LOCA, or a LOCA resulting from the failure of the RCP seals.

2 HoursA LOOP with successful emergency ac power and AFW, but with a PORV(s) failing to reclose resulting in a LOCA. Recovery of offsite power must occur with sufficient time to recover condenser vacuum and depressurize the reactor coolant system (RCS) to shutdown cooling initiation conditions (assumed to take 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) before refueling water storage tank (RWST) depletion and recirculation sump switch over at six hours. Failure requires the use of high-pressure recirculation.

LER 336/14-006 4

6 HoursA LOOP with successful emergency ac power with the failure of AFW and successful once through cooling. Recovery of offsite power must occur with sufficient time to recover secondary side cooling before RWST depletion and recirculation sump switch over at six hours. Failure requires the use of high-pressure recirculation.

8 HoursA LOOP and subsequent SBO with successful running of the turbine-driven AFW pump with no subsequent LOCA (e.g., PORV failing to reclose or RCP seal failure). Operators must restore offsite power prior to the battery depletion time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

The key offsite power recovery times for Millstone Unit 3 that are modeled within the SPAR model are:

1 HourA LOOP and subsequent SBO with failure of all turbine-driven AFW pump, failure of a PORV(s) to reclose resulting in a LOCA, or a LOCA resulting from the failure of the RCP seals.

2 HoursA LOOP with successful emergency ac power and AFW, but with a PORV(s) failing to reclose resulting in a LOCA. Recovery of offsite power must occur with sufficient time to recover condenser vacuum and depressurize the reactor coolant system (RCS) to shutdown cooling initiation conditions (assumed to take 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) before refueling water storage tank (RWST) depletion and recirculation sump switch over at six hours. Failure requires the use of high-pressure recirculation. In addition, the 2-hour recovery time applies to a LOOP and subsequent SBO with failure of both stages of RCP seals resulting in a 480 gpm/RCP LOCA. Operators must recover offsite power prior to core uncovery.

3 Hours A LOOP and subsequent SBO with operators failing to depressurize the secondary and the failure (binding/popping or o-ring extrusion) of Stage 2 of RCP seals resulting in a 176-182 gpm/RCP LOCA. Operators must recover offsite power prior to core uncovery.

4 HoursA LOOP and subsequent SBO with operators successfully depressurizing the secondary and the failure (binding/popping) of Stage 2 of RCP seals resulting in a 182 gpm/RCP LOCA. Operators must recover offsite power prior to core uncovery.

6 HoursA LOOP with successful emergency ac power with the failure of AFW and successful once through cooling. Recovery of offsite power must occur with sufficient time to recover secondary side cooling before RWST depletion and recirculation sump switch over at six hours. Failure requires the use of high-pressure recirculation. In addition, the 6-hour recovery time applies to a LOOP and subsequent SBO with operators failing to depressurize the secondary and the failure (o-ring extrusion) of Stage 1 of RCP seals resulting in a 61 gpm/RCP LOCA. Operators must recover offsite power prior to core uncovery.

8 HoursA LOOP and subsequent SBO with successful running of the turbine-driven AFW pump with no subsequent LOCA (e.g., PORV failing to reclose or RCP seal failure). Operators must restore offsite power prior to the battery depletion time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

Offsite power was restored to both units reserve station service transformers (RSSTs) approximately 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after the LOOP occurred. It took an additional 30 minutes (approximately) for operators to restore offsite power to the first safety bus for each unit.

However, this could be done more quickly (5-10 minutes) if more immediate power recovery

LER 336/14-006 5

was needed (e.g., postulated SBO). Based on this information, recovery of offsite power to a safety bus prior to 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> is assumed to fail for both units.

Therefore, the recovery action OEP-XHE-XL-N01H (Operator Fails to Recover Offsite Power in 1 Hour), and OEP-XHE-XL-N02H (Operator Fails to Recover Offsite Power in 2 Hours) were set to TRUE for Unit 2. For Unit 3, OEP-XHE-XL-N01HGR (Operator Fails to Recover Offsite Power in 1 Hour (Grid-Related)), OEP-XHE-XL-N02HGR (Operator Fails to Recover Offsite Power in 2 Hours (Grid-Related)), and OEP-XHE-XL-N03HGR (Operator Fails to Recover Offsite Power in 3 Hours (Grid-Related)) were set to TRUE.

Credit was given for offsite power recovery for applicable times greater than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. The SPAR-H Human Reliability Analysis Method (Reference 3 and Reference 4) was used to estimate non-recovery probabilities as a function of time following restoration of offsite power to the switchyard.

Tables 1 and 2 provide the key qualitative information for this recovery and the performance shaping factor (PSFs) adjustments required for the quantification of offsite power recovery events for times greater than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> using SPAR-H.

Table 1. Key Qualitative Information for Offsite Power Recovery after 3 Hours.

Definition The definition for overall recovery is the operators failure to align the RSST to re-energize a safety bus in 4 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (depending on the sequence).

Description and Event Context Depending on postulated failures of the EDGs, RCP seals (due to unavailability of seal injection/cooling), PORV(s) reclosing after demand, the availability of the turbine-driven AFW pump, and the time until the station batteries are depleted, operators would have between 4-8 hours to re-energize prior to core uncovery.

Operator Action Success Criteria Once power has been restored to the RSST, operators would need to close one of the RSS supply breakers to energize a safety bus. The time available for operators to perform this action would be a minimum of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Nominal Cues Loss of voltage on one or more safety buses Procedural Guidance Unit 2

• EOP 2528, Loss of Offsite Power/Loss of Forced Circulation

• EOP 2530, Station Blackout

• Appendix 23, Restoring Electrical Power Unit 3

• EOP 35, ECA-0.0, Loss of All AC Power

• EOP 35, GA-3, Energizing 4.16V Bus from Offsite Power Diagnosis/Action This recovery action contains diagnosis and action activities.

LER 336/14-006 6

Table 2. SPAR-H Evaluation for Offsite Power Recovery after 3 Hours.

PSF Multiplier Diagnosis / Action Notes Time Available 0.01 / 1 For recovery actions with 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or more available, approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (at a minimum) would be available to perform the actions required to re-energize a safety bus prior to core uncovery.

Therefore, the diagnosis PSF for available time is assigned as Expansive Time (i.e., x0.01; time available is >2 times nominal and >30 minutes).

Sufficient time exists to perform the action component of the offsite power recovery; therefore, the action PSF for available time is set to Nominal. See Reference 4 for guidance on apportioning time between the diagnosis and action components of an HFE.

Stress 2 / 1 The PSF for diagnosis stress is assigned a value of High Stress (i.e., x2) due to the postulated SBO and that core damage will occur if operators fail to restore power to a safety bus.

The PSF for action stress was not determined to be a performance driver for this HFE; and therefore, was assigned a value of Nominal (i.e., x1).

Complexity 2 / 1 The PSF for diagnosis complexity is assigned a value of Moderately Complex (i.e., x2) because operators would have to deal with multiple equipment unavailabilities and the concurrent actions/multiple procedures during a LOOP and postulated SBO.

The PSF for action complexity was not determined to be a performance driver for this HFE; and therefore, was assigned a value of Nominal (i.e., x1).

Procedures Experience/Training, Ergonomics/HMI, Fitness for Duty, Work Processes 1 /1 No event information is available to warrant a change in these PSFs (diagnosis or action) from Nominal for this HFE.

Offsite power recovery actions with at least three hours of available time are calculated using the following SPAR-H formula:

Power Recovery HEP = (Product of Diagnosis PSFs

• Nominal Diagnosis HEP) +

(Product of Action PSFs

• Nominal Action HEP)

= (0.04

• 0.01) + (1

• 0.001) = 1x10-3 Therefore, the following Unit 2 HEPs for offsite power recovery, OEP-XHE-XL-NR06H (Operator Fails to Recover Offsite Power in 6 Hours) and OEP-XHE-XL-NR08H (Operator Fails to Recover Offsite Power in 8 Hours), are calculated to be 1x10-3.

The following Unit 3 HEPs for offsite power recovery, OEP-XHE-XL-NR04HGR (Operator Fails to Recover Offsite Power in 4 Hours(Grid-Related)), OEP-XHE-XL-NR06HGR

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(Operator Fails to Recover Offsite Power in 6 Hours(Grid-Related)), and OEP-XHE-XL-NR08HGR (Operator Fails to Recover Offsite Power in 8 Hours (Grid-Related)), are calculated to be 1x10-3.

The offsite power was recovered to at least one safety bus in both units in approximately 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> and 30 minutes after the LOOP occurred. Offsite power was restored to all safety buses (for both units) approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after the LOOP occurred. Therefore, the default EDG and turbine-driven AFW pump mission times were changed to reflect the actual time offsite power was restored to the safety 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 <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and ZT-TDP-FR-E = 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (nominal values) and ZT-DGN-FR-L = 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and ZT-TDP-FR-L= 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.

Key Modeling Assumptions for Unit 3. In addition, to the modeling assumptions above; the following assumptions were made in Unit 3 analysis:

The Basic Events PPR-SRV-CO-L (PORVs/SRVs Open during a LOOP) and PPR-SRV-CO-B (PORVs/SRVs Open during an SBO) were set to TRUE because operators used both PORVs to control RCS pressure due to the loss of letdown. There were 11 open/close cycles of both PORVs; PORV 455A was cycled six times and PORV 456 was cycled five times. Therefore, a binomial expansion was used to adjust the failure probabilities for Basic Events PPR-SRV-OO-455A (PORV 455A Fails to Reclose after Opening) and PPR-SRV-OO-456 (PORV 456 Fails to Reclose after Opening) to account for the increased probability that the valves could stick open. These probabilities were changed to 5.8x10-3 and 4.8x10-3, respectively.

The diesel-driven firewater pump was reported to be out of service. The firewater system is not modeled explicitly except two operator actions to align firewater for alternated supply of AFW and alternated cooling water to the charging pumps. Therefore, Basic Events AFW-XHE-XM-FIREW (Operator Fails to Align Firewater to AFW Suction) and CCE-XHE-XM-ACOOL (Operator Fails to Establish Firewater to the Charging Pump Cooling Heat Exchangers) were set to TRUE. This simplifying modeling assumption has a negligible impact on the Unit 3 CCDP.

ANALYSIS RESULTS CCDPs. The point estimate CCDPs for this event are 1.2x10-5 (Unit 2) and 1.6x10-5 (Unit 3).

The ASP Program acceptance threshold is a CCDP of 1x10-6 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 is 1x10-6 and 6x10-7, for Millstone Units 2 and 3, respectively. Therefore, this event resulted in a precursor for both units.

Unit 2 Dominant Sequence. The dominant accident sequence is LOOP/SBO Sequence 22-31 (CCDP = 8.1x10-6), which contributes approximately 67% of the total internal events CCDP.

The cut sets and sequences that contribute to the top 95% and/or at least 1% of the total internal events CCDP are provided in Appendix A.

The dominant sequence is shown graphically in Figures C-1 and C-2 in Appendix C. The events and important component failures in LOOP/SBO Sequence 22-31 are:

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A non-recoverable grid-related LOOP occurs, Reactor scram succeeds, Emergency powers fails, Safety relief valves reclose (if opened),

Turbine-driven AFW pump fails, and Operators fail to recover ac power (offsite power or EDGs) within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Unit 3 Dominant Sequence. The dominant accident sequence is LOOP/SBO Sequence 16-01-04 (CCDP =3.7 x10-6), which contributes approximately 23% of the total internal events CCDP. The cut sets and sequences that contribute to the top 95% and/or at least 1% of the total internal events CCDP are provided in Appendix B.

The dominant sequence is shown graphically in Figures C-3 and C-4 in Appendix C. The events and important component failures in LOOP/SBO Sequence 16-01-04 are:

A non-recoverable grid-related LOOP occurs, Reactor scram succeeds, Normal emergency powers fails resulting in an SBO, SBO diesel generator is successful, but not before RCP seals are challenged due to lack of cooling/injection, Safety relief valves reclose (if opened),

AFW is successful, Rapid secondary depressurization is successful, Stage 2 of the RCP seals fail (binding and popping),

Operators fail to recover ac power (offsite power or EDGs) within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, High-pressure injection is successful, and High-pressure recirculation fails.

REFERENCES

1. Dominion Nuclear Connecticut, Inc., "LER 336/14-006-Millstone Power Station Dual Unit Reactor Trip on Loss of Offsite Power, dated July 24, 2014 (ML14211A526).

2. U.S. Nuclear Regulatory Commission, Millstone Power Station Units 2 and 3 - NRC Special Inspection Report 05000336/2014011 AND 05000423/2014011, dated August 28, 2014 (ML14240A006).

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

4. Idaho National Laboratory, INL/EXT-10-18533, SPAR-H Step-by-Step Guidance, May 2011 (ML112060305).

LER 336/14-006 A-1 Appendix A: Unit 2 Analysis Results Summary of Conditional Event Changes Event Description Cond.

Value Nominal Value EPS-DGN-FC-UNIT3 BLACKOUT DIESEL IS REQUIRED BY UNIT 3 6.80E-4 0.00E+0 IE-LOOPa LOSS OF OFFSITE POWER 1.00E+0 2.84E-2 LOOP-DUAL-UNIT DUAL UNIT LOOP TRUE 5.82E-1 LOOP-SNGL-UNIT SINGLE UNIT LOOP FALSE 4.18E-1 OEP-XHE-XL-NR01H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR TRUE 5.46E-1 OEP-XHE-XL-NR02H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 2 HOURS TRUE 3.39E-1 OEP-XHE-XL-NR06H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 6 HOURS 1.00E-3 1.10E-1 OEP-XHE-XL-NR08H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 8 HOURS 1.00E-3 7.82E-2 ZT-DGN-FR-L DIESEL GENERATOR FAILS TO RUN 2.70E-3 2.47E-2 ZT-TDP-FR-L TURBINE DRIVEN PUMP FAILS TO RUN 7.80E-3 3.52E-2

a.

All other initiating event probabilities were set to zero.

Dominant Sequence Results Only items contributing at least 1.0% to the total CCDP are displayed.

Event Tree Sequence CCDP

% Contribution Description LOOP 22-31 8.06E-6 67.1%

/RPS, EPS, EPS-SBO, AFW-B, OPR-01H, DGR-01H LOOP 21 3.59E-6 29.9%

/RPS, /EPS, AFW-L, OTC-L Total 1.20E-5 100.0%

Referenced Fault Trees Fault Tree Description AFW-B MILLSTONE 2 AUXILIARY FEEDWATER USING SBO-FTF FLAG SET AFW-L MILLSTONE 2 AUXILIARY FEEDWATER USING LOOP-FTF FLAG SET DGR-01H MILLSTONE 2 OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR EPS EMERGENCY POWER EPS-SBO STATION BLACKOUT POWER OPR-01H OFFSITE POWER RECOVERY IN 1 HOUR OTC-L MILLSTONE 2 ONCE THROUGH COOLING USING LOOP-FTF FAULT TREE FLAGS Cut Set Report - LOOP 22-31 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 8.06E-6 100 Displaying 5766 Cut Sets. (5766 Original) 1 6.36E-7 7.88 IE-LOOP,AFW-XHE-XM-TDP,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 2

3.88E-7 4.82 IE-LOOP,AFW-TDP-FR-TDP,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 3

3.54E-7 4.39 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-FR-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H 4

3.54E-7 4.39 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-FR-DGB,EPS-DGN-TM-DGA,EPS-XHE-XL-NR01H 5

3.36E-7 4.16 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-CF-RUN,EPS-XHE-XL-NR01H

LER 336/14-006 A-2 CCDP Total%

Cut Set 6

2.06E-7 2.56 IE-LOOP,AFW-TDP-FS-TDP,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 7

2.03E-7 2.51 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-FR-DGA,EPS-DGN-FR-DGB,EPS-XHE-XL-NR01H 8

1.99E-7 2.46 IE-LOOP,AFW-XHE-XM-TDP,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H 9

1.71E-7 2.13 IE-LOOP,AFW-TDP-TM-TDP,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 10 1.25E-7 1.55 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-FS-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H 11 1.25E-7 1.55 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-FS-DGB,EPS-DGN-TM-DGA,EPS-XHE-XL-NR01H 12 1.21E-7 1.50 IE-LOOP,AFW-TDP-FR-TDP,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H 13 1.09E-7 1.35 IE-LOOP,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-CF-START,EPS-XHE-XL-NR01H 14 1.03E-7 1.28 IE-LOOP,ACP-CRB-CC-24DIT2,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-TM-DGA,EPS-XHE-XL-NR01H 15 1.03E-7 1.28 IE-LOOP,ACP-CRB-CC-S324D2,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-TM-DGA,EPS-XHE-XL-NR01H 16 1.03E-7 1.28 IE-LOOP,ACP-CRB-CC-24CIT2,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H 17 1.03E-7 1.28 IE-LOOP,ACP-CRB-CC-S324C2,ACP-XHE-XM-ALT,AFW-XHE-XM-TDP1,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H Cut Set Report - LOOP 21 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 3.60E-6 100 Displaying 8266 Cut Sets. (8266 Original) 1 6.39E-8 1.78 IE-LOOP,AFW-AOV-CF-FW43AB,AFW-XHE-XM-BYPASS,HPI-XHE-XM-FBL 2

5.29E-8 1.47 IE-LOOP,AFW-XHE-XM-TDP,DCP-BCH-CF-CHR,DCP-XHE-XM-CH201C 3

4.56E-8 1.27 IE-LOOP,AFW-MDP-TM-9B,AFW-XHE-XM-TDP,EPS-DGN-FR-DGA,PPR-MOV-FC-BLK1 4

4.56E-8 1.27 IE-LOOP,AFW-MDP-TM-9A,AFW-XHE-XM-TDP,EPS-DGN-FR-DGB,PPR-MOV-FC-BLK2 5

3.84E-8 1.07 IE-LOOP,AFW-MDP-TM-9A,AFW-XHE-XM-TDP,EPS-DGN-FR-DGB,IAS-MDC-FR-IAF3A 6

3.84E-8 1.07 IE-LOOP,AFW-MDP-TM-9B,AFW-XHE-XM-TDP,EPS-DGN-FR-DGA,IAS-MDC-FR-IAF3B Referenced Events Event Description Probability ACP-CRB-CC-24CIT2 FAILURE OF OFFSITE LINE CRB 24C-IT-2 FROM BUS 24A TO OPEN 2.39E-3 ACP-CRB-CC-24DIT2 FAILURE OF OFFSITE LINE CRB 24D-IT-2 FROM BUS 24B TO OPEN 2.39E-3 ACP-CRB-CC-S324C2 FAILURE OF OFFSITE LINE CRB 22S3-24C-2 FROM RSST TO OPEN 2.39E-3 ACP-CRB-CC-S324D2 FAILURE OF OFFSITE LINE CRB 22S3-24D-2 FROM RSST TO OPEN 2.39E-3 ACP-XHE-XM-ALT OPERATOR FAILS TO START AND ALIGN SBO DGN 5.00E-2 AFW-AOV-CF-FW43AB COMMON CAUSE FAILURE OF FLOW CONTROL VALVES 2-FW-43A/43B 3.19E-5 AFW-MDP-TM-9A AFW MOTOR-DRIVEN PUMP 9A UNAVAILABLE DUE TO T & M 3.98E-3 AFW-MDP-TM-9B AFW MOTOR-DRIVEN PUMP 9B UNAVAILABLE DUE TO T & M 3.98E-3 AFW-TDP-FR-TDP AFW TURBINE-DRIVEN PUMP FAILS TO RUN 1.22E-2 AFW-TDP-FS-TDP AFW TURBINE-DRIVEN PUMP FAILS TO START 6.49E-3 AFW-TDP-TM-TDP AFW TURBINE-DRIVEN PUMP UNAVAILABLE DUE TO T & M 5.39E-3 AFW-XHE-XM-BYPASS OPERATOR FAILS TO OPEN BYPASS VALVES FW-56A OR 56B 1.00E-1 AFW-XHE-XM-TDP OPERATOR FAILS TO LOCALLY START/OPERATE TDP 2.00E-2 AFW-XHE-XM-TDP1 OPERATOR FAILS TO LOCALLY START TDP 6.90E-2 DCP-BCH-CF-CHR CCF OF BATTERY CHARGERS 2.64E-6

LER 336/14-006 A-3 Event Description Probability DCP-XHE-XM-CH201C OPERATOR FAILS TO ALIGN CHARGE 201C TO FAILED BUS 1.00E+0 EPS-DGN-CF-RUN COMMON CAUSE FAILURE OF DIESEL GENERATORS TO RUN 1.12E-4 EPS-DGN-CF-RUN3 COMMON CAUSE FAILURE OF DIESEL GENERATORS TO RUN 3.65E-5 EPS-DGN-CF-START COMMON CAUSE FAILURE OF DIESEL GENERATORS TO START 3.61E-5 EPS-DGN-CF-START3 COMMON CAUSE FAILURE OF DIESEL GENERATORS TO START 1.14E-5 EPS-DGN-FR-DGA DIESEL GENERATOR A FAILS TO RUN 8.21E-3 EPS-DGN-FR-DGB DIESEL GENERATOR B FAILS TO RUN 8.21E-3 EPS-DGN-FS-DGA DIESEL GENERATOR A FAILS TO START 2.89E-3 EPS-DGN-FS-DGB DIESEL GENERATOR B FAILS TO START 2.89E-3 EPS-DGN-TM-DGA DIESEL GENERATOR A UNAVAILABLE DUE T & M 1.43E-2 EPS-DGN-TM-DGB DIESEL GENERATOR B UNAVAILABLE DUE T & M 1.43E-2 EPS-XHE-XL-NR01H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR 8.71E-1 HPI-XHE-XM-FBL OPERATOR FAILS TO INITIATE F&B COOLING GIVEN A LOOP 2.00E-2 IAS-MDC-FR-IAF3A INSTRUMENT AIR COMPRESSOR F3A FAILS TO RUN 5.89E-2 IAS-MDC-FR-IAF3B INSTRUMENT AIR COMPRESSOR F3B FAILS TO RUN 5.89E-2 IE-LOOP LOSS OF OFFSITE POWER 1.00E+0 PPR-MOV-FC-BLK1 PORV 402 BLOCK VALVE 403 CLOSED DURING POWER 6.99E-2 PPR-MOV-FC-BLK2 PORV 404 BLOCK VALVE 405 CLOSED DURING FULL POWER 6.99E-2

LER 336/14-006 B-1 Appendix B: Unit 3 Analysis Results Summary of Conditional Event Changes Event Description Cond.

Value Nominal Value AFW-XHE-XM-FIREW OPERATOR FAILS TO ALIGN FWS OR OTHER SOURCE TO AFW SUCTION TRUE 1.00E-3 CCE-XHE-XM-ACOOL OPERATOR FAILS TO ESTABLISH FIRE WATER TO CCE HTXs TRUE 2.00E-2 EPS-DGN-FC-UNIT2 BLACKOUT DIESEL IS REQUIRED BY UNIT 2 6.80E-4 0.00E+0 IE-LOOPGRa LOSS OF OFFSITE POWER (GRID-RELATED) 1.00E+0 2.84E-2 LOOP-DUAL-UNIT DUAL UNIT LOOP TRUE 5.82E-1 LOOP-SNGL-UNIT SINGLE UNIT LOOP FALSE 4.18E-1 OEP-XHE-XL-NR01HGR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR (GRID-RELATED)

TRUE 6.59E-1 OEP-XHE-XL-NR02HGR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 2 HOURS (GRID-RELATED)

TRUE 3.91E-1 OEP-XHE-XL-NR04HGR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 4 HOURS (GRID-RELATED) 1.00E-3 1.69E-1 OEP-XHE-XL-NR06HGR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 6 HOURS (GRID-RELATED) 1.00E-3 8.68E-2 OEP-XHE-XL-NR08HGR OPERATOR FAILS TO RECOVER OFFSITE POWER IN 8 HOURS(GRID-RELATED) 1.00E-3 5.00E-2 PPR-SRV-CO-L PORVs/SRVs OPEN DURING LOOP TRUE 1.48E-1 PPR-SRV-CO-SBO PORVs/SRVs OPEN DURING SBO TRUE 3.70E-1 PPR-SRV-OO-455A PORV 455A FAILS TO RECLOSE AFTER OPENING 5.80E-3 9.66E-4 PPR-SRV-OO-456 PORV 456 FAILS TO RECLOSE AFTER OPENING 4.80E-3 9.66E-4 ZT-DGN-FR-L DIESEL GENERATOR FAILS TO RUN 2.70E-3 2.47E-2 ZT-TDP-FR-L TURBINE DRIVEN PUMP FAILS TO RUN 7.80E-3 3.52E-2

a.

All other initiating event probabilities were set to zero.

Dominant Sequence Results Only items contributing at least 1.0% to the total CCDP are displayed.

Event Tree Sequence CCDP

% Contribution Description LOOPGR 16-01-04 3.65E-6 23.3%

/RPS-L, EPS, /EPS-SBO, /RSD, /BP1, BP2, OPR-02H, /HPI-B, HPR-B LOOPGR 09 2.87E-6 18.3%

/RPS-L, /EPS, /AFW-L, PORV-L, /HPI-L, OPR-02H, HPR-L LOOPGR 02-04 2.41E-6 15.4%

/RPS-L, /EPS, /AFW-L, /PORV-L, LOSC-L, /RSD, /BP1, BP2, OPR-02H, /HPI-L, HPR-L LOOPGR 02-05 1.85E-6 11.8%

/RPS-L, /EPS, /AFW-L, /PORV-L, LOSC-L, /RSD, /BP1, BP2, OPR-02H, HPI-L LOOPGR 16-46 1.65E-6 10.5%

/RPS-L, EPS, EPS-SBO, AFW-B, OPR-01H, DGR-01H LOOPGR 16-01-05 8.15E-7 5.2%

/RPS-L, EPS, /EPS-SBO, /RSD, /BP1, BP2, OPR-02H, HPI-B LOOPGR 16-43 7.20E-7 4.6%

/RPS-L, EPS, EPS-SBO, /AFW-B, PORV-B, OPR-01H, DGR-01H LOOPGR 15 6.82E-7 4.4%

/RPS-L, /EPS, AFW-L, FAB-L LOOPGR 16-01-08 1.82E-7 1.2%

/RPS-L, EPS, /EPS-SBO, /RSD, BP1, /BP2, OPR-02H, /HPI-B, HPR-B Total 1.56E-5 100.0%

LER 336/14-006 B-2 Referenced Fault Trees Fault Tree Description AFW-B AUXILIARY FEEDWATER SYSTEM DURING SBO AFW-L AUXILIARY FEEDWATER SYSTEM DURING LOOP BP1 RCP SEAL STAGE 1 INTEGRITY BP2 RCP SEAL STAGE 2 INTEGRITY DGR-01H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR EPS EMERGENCY POWER EPS-SBO STATION BLACKOUT POWER FAB-L FEED AND BLEED DURING LOOP HPI-B HIGH PRESSURE INJECTION SBO SEQUENCES W/ SBO DGN OPERATING HPI-L HIGH PRESSURE INJECTION HPR-B HIGH PRESSURE RECIRCULATION SBO SEQUENCES W/ SBO DGN OPERATING HPR-L HIGH PRESSURE RECIRC LOSC-L RCP SEAL COOLING MAINTAINED DURING LOOP OPR-01H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR OPR-02H OFFSITE POWER RECOVERY IN 2 HRS PORV-B PORVs/SRVs OPEN DURING STATION BLACKOUT PORV-L PORVs ARE CLOSED DURING LOOP Cut Set Report - LOOPGR 16-01-04 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 3.65E-6 100 Displaying 1786 Cut Sets. (1786 Original) 1 9.44E-8 2.58 IE-LOOPGR,ACP-BAC-LP-32U,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 2 9.44E-8 2.58 IE-LOOPGR,ACP-BAC-LP-32T,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 3 6.42E-8 1.76 IE-LOOPGR,ACP-TFM-FC-34D21X,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 4 6.42E-8 1.76 IE-LOOPGR,ACP-TFM-FC-34C31X,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 5 5.40E-8 1.48 IE-LOOPGR,ACP-BAC-LP-32T,EPS-DGN-FR-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 6 5.40E-8 1.48 IE-LOOPGR,ACP-BAC-LP-32U,EPS-DGN-FR-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 7 3.92E-8 1.07 IE-LOOPGR,CVC-MOV-OO-8512B,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 8 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,RHR-MOV-OO-8812A,SBO-DGN-ALIGN34C 9 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,RHR-MOV-OO-8812B,SBO-DGN-ALIGN34D 10 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,LPI-MOV-CC-8804A,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 11 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,LPI-MOV-CC-8804B,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 12 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,HPI-MOV-OO-8813,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 13 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,HPI-MOV-OO-8814,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C

LER 336/14-006 B-3 CCDP Total%

Cut Set 14 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,HPI-MOV-OO-8920,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 15 3.92E-8 1.07 IE-LOOPGR,CVC-MOV-OO-8511A,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 16 3.92E-8 1.07 IE-LOOPGR,CVC-MOV-OO-8512A,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 17 3.92E-8 1.07 IE-LOOPGR,CVC-MOV-OO-8511B,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 18 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C,SWS-MOV-OO-50A 19 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D,SWS-MOV-OO-50B 20 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C,SWS-MOV-OO-71A 21 3.92E-8 1.07 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D,SWS-MOV-OO-71B 22 3.67E-8 1.01 IE-LOOPGR,ACP-TFM-FC-34C31X,EPS-DGN-FR-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 23 3.67E-8 1.01 IE-LOOPGR,ACP-TFM-FC-34D21X,EPS-DGN-FR-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D Cut Set Report - LOOPGR 09 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 2.87E-6 100 Displaying 826 Cut Sets. (826 Original) 1 1.66E-7 5.81 IE-LOOPGR,EPS-DGN-TM-DGA,HPI-XHE-XM-RECIRC,PPR-SRV-OO-455A 2

1.38E-7 4.80 IE-LOOPGR,EPS-DGN-TM-DGB,HPI-XHE-XM-RECIRC,PPR-SRV-OO-456 3

9.52E-8 3.32 IE-LOOPGR,EPS-DGN-FR-DGA,HPI-XHE-XM-RECIRC,PPR-SRV-OO-455A 4

8.02E-8 2.80 IE-LOOPGR,CVC-MOV-OO-8512B,EPS-DGN-TM-DGA,PPR-SRV-OO-455A 5

8.02E-8 2.80 IE-LOOPGR,EPS-DGN-TM-DGA,HPI-MOV-OO-8813,PPR-SRV-OO-455A 6

8.02E-8 2.80 IE-LOOPGR,EPS-DGN-TM-DGA,PPR-SRV-OO-455A,RHR-MOV-OO-8812B 7

8.02E-8 2.80 IE-LOOPGR,EPS-DGN-TM-DGA,PPR-SRV-OO-455A,SWS-MOV-OO-50B 8

8.02E-8 2.80 IE-LOOPGR,EPS-DGN-TM-DGA,LPI-MOV-CC-8804B,PPR-SRV-OO-455A 9

8.02E-8 2.80 IE-LOOPGR,EPS-DGN-TM-DGA,PPR-SRV-OO-455A,SWS-MOV-OO-71B 10 8.02E-8 2.80 IE-LOOPGR,CVC-MOV-OO-8511B,EPS-DGN-TM-DGA,PPR-SRV-OO-455A 11 7.88E-8 2.75 IE-LOOPGR,EPS-DGN-FR-DGB,HPI-XHE-XM-RECIRC,PPR-SRV-OO-456 12 6.63E-8 2.31 IE-LOOPGR,EPS-DGN-TM-DGB,HPI-MOV-OO-8814,PPR-SRV-OO-456 13 6.63E-8 2.31 IE-LOOPGR,EPS-DGN-TM-DGB,HPI-MOV-OO-8920,PPR-SRV-OO-456 14 6.63E-8 2.31 IE-LOOPGR,EPS-DGN-TM-DGB,LPI-MOV-CC-8804A,PPR-SRV-OO-456 15 6.63E-8 2.31 IE-LOOPGR,EPS-DGN-TM-DGB,PPR-SRV-OO-456,SWS-MOV-OO-50A 16 6.63E-8 2.31 IE-LOOPGR,EPS-DGN-TM-DGB,PPR-SRV-OO-456,RHR-MOV-OO-8812A 17 6.63E-8 2.31 IE-LOOPGR,EPS-DGN-TM-DGB,PPR-SRV-OO-456,SWS-MOV-OO-71A 18 6.63E-8 2.31 IE-LOOPGR,CVC-MOV-OO-8511A,EPS-DGN-TM-DGB,PPR-SRV-OO-456 19 6.63E-8 2.31 IE-LOOPGR,CVC-MOV-OO-8512A,EPS-DGN-TM-DGB,PPR-SRV-OO-456 20 4.59E-8 1.60 IE-LOOPGR,CVC-MOV-OO-8512B,EPS-DGN-FR-DGA,PPR-SRV-OO-455A 21 4.59E-8 1.60 IE-LOOPGR,EPS-DGN-FR-DGA,HPI-MOV-OO-8813,PPR-SRV-OO-455A 22 4.59E-8 1.60 IE-LOOPGR,EPS-DGN-FR-DGA,PPR-SRV-OO-455A,RHR-MOV-OO-8812B 23 4.59E-8 1.60 IE-LOOPGR,EPS-DGN-FR-DGA,PPR-SRV-OO-455A,SWS-MOV-OO-50B 24 4.59E-8 1.60 IE-LOOPGR,EPS-DGN-FR-DGA,LPI-MOV-CC-8804B,PPR-SRV-OO-455A

LER 336/14-006 B-4 CCDP Total%

Cut Set 25 4.59E-8 1.60 IE-LOOPGR,EPS-DGN-FR-DGA,PPR-SRV-OO-455A,SWS-MOV-OO-71B 26 4.59E-8 1.60 IE-LOOPGR,CVC-MOV-OO-8511B,EPS-DGN-FR-DGA,PPR-SRV-OO-455A 27 3.80E-8 1.32 IE-LOOPGR,EPS-DGN-FR-DGB,HPI-MOV-OO-8814,PPR-SRV-OO-456 28 3.80E-8 1.32 IE-LOOPGR,EPS-DGN-FR-DGB,HPI-MOV-OO-8920,PPR-SRV-OO-456 29 3.80E-8 1.32 IE-LOOPGR,EPS-DGN-FR-DGB,LPI-MOV-CC-8804A,PPR-SRV-OO-456 30 3.80E-8 1.32 IE-LOOPGR,EPS-DGN-FR-DGB,PPR-SRV-OO-456,SWS-MOV-OO-50A 31 3.80E-8 1.32 IE-LOOPGR,EPS-DGN-FR-DGB,PPR-SRV-OO-456,RHR-MOV-OO-8812A 32 3.80E-8 1.32 IE-LOOPGR,EPS-DGN-FR-DGB,PPR-SRV-OO-456,SWS-MOV-OO-71A 33 3.80E-8 1.32 IE-LOOPGR,CVC-MOV-OO-8511A,EPS-DGN-FR-DGB,PPR-SRV-OO-456 34 3.80E-8 1.32 IE-LOOPGR,CVC-MOV-OO-8512A,EPS-DGN-FR-DGB,PPR-SRV-OO-456 35 3.35E-8 1.17 IE-LOOPGR,EPS-DGN-FS-DGA,HPI-XHE-XM-RECIRC,PPR-SRV-OO-455A Cut Set Report - LOOPGR 02-04 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 2.41E-6 100 Displaying 4493 Cut Sets. (4493 Original) 1 4.70E-8 1.95 IE-LOOPGR,ACP-BAC-LP-32W,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 2

4.70E-8 1.95 IE-LOOPGR,ACP-BAC-LP-32W,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 3

4.70E-8 1.95 IE-LOOPGR,ACP-BAC-LP-32R,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 4

4.70E-8 1.95 IE-LOOPGR,ACP-BAC-LP-32R,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 5

3.19E-8 1.32 IE-LOOPGR,ACP-TFM-FC-34D41X,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 6

3.19E-8 1.32 IE-LOOPGR,ACP-TFM-FC-34D41X,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 7

3.19E-8 1.32 IE-LOOPGR,ACP-TFM-FC-34C51X,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 8

3.19E-8 1.32 IE-LOOPGR,ACP-TFM-FC-34C51X,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 9

2.69E-8 1.11 IE-LOOPGR,ACP-BAC-LP-32W,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-FR-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 10 2.69E-8 1.11 IE-LOOPGR,ACP-BAC-LP-32W,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-FR-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 11 2.69E-8 1.11 IE-LOOPGR,ACP-BAC-LP-32R,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-FR-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 12 2.69E-8 1.11 IE-LOOPGR,ACP-BAC-LP-32R,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-FR-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 Cut Set Report - LOOPGR 02-05 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 1.85E-6 100 Displaying 3360 Cut Sets. (3360 Original) 1 4.81E-8 2.60 IE-LOOPGR,CVC-P3AOP-P3BSTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1CRUN-1ASTBY,SWS-1DRUN-1BSTBY,SWS-MDP-CF-START 2

4.81E-8 2.60 IE-LOOPGR,CVC-P3AOP-P3BSTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1ARUN-1CSTBY,SWS-1DRUN-1BSTBY,SWS-MDP-CF-START 3

4.81E-8 2.60 IE-LOOPGR,CVC-P3AOP-P3BSTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1ARUN-1CSTBY,SWS-1BRUN-1DSTBY,SWS-MDP-CF-START

LER 336/14-006 B-5 CCDP Total%

Cut Set 4

4.81E-8 2.60 IE-LOOPGR,CVC-P3BOP-P3ASTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1ARUN-1CSTBY,SWS-1DRUN-1BSTBY,SWS-MDP-CF-START 5

4.81E-8 2.60 IE-LOOPGR,CVC-P3BOP-P3ASTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1ARUN-1CSTBY,SWS-1BRUN-1DSTBY,SWS-MDP-CF-START 6

4.81E-8 2.60 IE-LOOPGR,CVC-P3BOP-P3ASTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1CRUN-1ASTBY,SWS-1DRUN-1BSTBY,SWS-MDP-CF-START 7

4.81E-8 2.60 IE-LOOPGR,CVC-P3AOP-P3BSTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1BRUN-1DSTBY,SWS-1CRUN-1ASTBY,SWS-MDP-CF-START 8

4.81E-8 2.60 IE-LOOPGR,CVC-P3BOP-P3ASTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-1BRUN-1DSTBY,SWS-1CRUN-1ASTBY,SWS-MDP-CF-START 9

2.12E-8 1.15 IE-LOOPGR,CCW-1A1BRUN-1CSTBY,CVC-MDP-TM-P3A,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGB,HPI-MDP-TM-P1A,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 10 2.12E-8 1.15 IE-LOOPGR,CCW-1A1BRUN-1CSTBY,CVC-MDP-TM-P3B,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGA,HPI-MDP-TM-P1B,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 11 2.08E-8 1.12 IE-LOOPGR,CVC-P3BOP-P3ASTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-FAN-CF-HVY2ABS,SWS-XHE-XL-VENT 12 2.08E-8 1.12 IE-LOOPGR,CVC-P3AOP-P3BSTBY,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SWS-FAN-CF-HVY2ABS,SWS-XHE-XL-VENT 13 1.95E-8 1.05 IE-LOOPGR,CCE-MDP-TM-P1A,CCE-P3BOP-P3ASTBY,CCW-1A1BRUN-1CSTBY,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGB,HPI-MDP-TM-P1A,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 14 1.95E-8 1.05 IE-LOOPGR,CCE-MDP-TM-P1B,CCE-P3AOP-P3BSTBY,CCW-1A1BRUN-1CSTBY,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGA,HPI-MDP-TM-P1B,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2 Cut Set Report - LOOPGR 16-46 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 1.64E-6 100 Displaying 701 Cut Sets. (701 Original) 1 3.87E-7 23.55 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 2 2.06E-7 12.52 IE-LOOPGR,AFW-TDP-FS-P2,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 3 1.71E-7 10.40 IE-LOOPGR,AFW-TDP-TM-P2,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H 4 1.21E-7 7.37 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H 5 6.45E-8 3.92 IE-LOOPGR,AFW-TDP-FS-P2,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H 6 5.35E-8 3.26 IE-LOOPGR,AFW-TDP-TM-P2,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H 7 2.19E-8 1.33 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H,EPS-XHE-XM-SBO 8 1.80E-8 1.09 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-FR-DGA,EPS-DGN-TM-DGB,EPS-DGN-TM-SBO,EPS-XHE-XL-NR01H 9 1.80E-8 1.09 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-FR-DGB,EPS-DGN-TM-DGA,EPS-DGN-TM-SBO,EPS-XHE-XL-NR01H 10 1.80E-8 1.09 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-FR-SBO,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H 11 1.71E-8 1.04 IE-LOOPGR,AFW-TDP-FR-P2,EPS-DGN-CF-RUN,EPS-DGN-TM-SBO,EPS-XHE-XL-NR01H Cut Set Report - LOOPGR 16-01-05 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 8.15E-7 100 Displaying 1419 Cut Sets. (1419 Original) 1 9.44E-8 11.58 IE-LOOPGR,ACP-BAC-LP-34D,EPS-DGN-TM-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D

LER 336/14-006 B-6 CCDP Total%

Cut Set 2 9.44E-8 11.58 IE-LOOPGR,ACP-BAC-LP-34C,EPS-DGN-TM-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 3 6.16E-8 7.55 IE-LOOPGR,ACP-TFM-CF-C3D2,CVC-P3BOP-P3ASTBY,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 4 6.16E-8 7.55 IE-LOOPGR,ACP-TFM-CF-C3D2,CVC-P3AOP-P3BSTBY,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 5 5.40E-8 6.63 IE-LOOPGR,ACP-BAC-LP-34C,EPS-DGN-FR-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 6 5.40E-8 6.63 IE-LOOPGR,ACP-BAC-LP-34D,EPS-DGN-FR-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 7 3.54E-8 4.34 IE-LOOPGR,ACP-BAC-LP-32U,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGA,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 8 3.54E-8 4.34 IE-LOOPGR,ACP-BAC-LP-32T,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGB,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 9 2.41E-8 2.95 IE-LOOPGR,ACP-TFM-FC-34D21X,CVC-P3BOP-P3ASTBY,EPS-DGN-TM-DGA,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 10 2.41E-8 2.95 IE-LOOPGR,ACP-TFM-FC-34C31X,CVC-P3AOP-P3BSTBY,EPS-DGN-TM-DGB,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 11 2.03E-8 2.49 IE-LOOPGR,ACP-BAC-LP-32U,CVC-P3BOP-P3ASTBY,EPS-DGN-FR-DGA,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 12 2.03E-8 2.49 IE-LOOPGR,ACP-BAC-LP-32T,CVC-P3AOP-P3BSTBY,EPS-DGN-FR-DGB,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 13 1.90E-8 2.33 IE-LOOPGR,ACP-BAC-LP-34C,EPS-DGN-FS-DGB,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 14 1.90E-8 2.33 IE-LOOPGR,ACP-BAC-LP-34D,EPS-DGN-FS-DGA,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 15 1.38E-8 1.69 IE-LOOPGR,ACP-TFM-FC-34D21X,CVC-P3BOP-P3ASTBY,EPS-DGN-FR-DGA,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 16 1.38E-8 1.69 IE-LOOPGR,ACP-TFM-FC-34C31X,CVC-P3AOP-P3BSTBY,EPS-DGN-FR-DGB,NOTWINTER,/RCS-MDP-LK-BP1,RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C Cut Set Report - LOOPGR 16-43 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 7.21E-7 100 Displaying 365 Cut Sets. (365 Original) 1 1.84E-7 25.52 IE-LOOPGR,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H,PPR-SRV-OO-455A 2 1.52E-7 21.12 IE-LOOPGR,EPS-DGN-CF-RUN3,EPS-XHE-XL-NR01H,PPR-SRV-OO-456 3 5.76E-8 7.99 IE-LOOPGR,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H,PPR-SRV-OO-455A 4 4.76E-8 6.61 IE-LOOPGR,EPS-DGN-CF-START3,EPS-XHE-XL-NR01H,PPR-SRV-OO-456 5 1.04E-8 1.44 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H,EPS-XHE-XM-SBO,PPR-SRV-OO-455A 6 8.61E-9 1.20 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H,EPS-XHE-XM-SBO,PPR-SRV-OO-456 7 8.54E-9 1.19 IE-LOOPGR,EPS-DGN-FR-SBO,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,EPS-XHE-XL-NR01H,PPR-SRV-OO-455A 8 8.54E-9 1.19 IE-LOOPGR,EPS-DGN-FR-DGA,EPS-DGN-TM-DGB,EPS-DGN-TM-SBO,EPS-XHE-XL-NR01H,PPR-SRV-OO-455A 9 8.54E-9 1.19 IE-LOOPGR,EPS-DGN-FR-DGB,EPS-DGN-TM-DGA,EPS-DGN-TM-SBO,EPS-XHE-XL-NR01H,PPR-SRV-OO-455A 10 8.10E-9 1.12 IE-LOOPGR,EPS-DGN-CF-RUN,EPS-DGN-TM-SBO,EPS-XHE-XL-NR01H,PPR-SRV-OO-455A

LER 336/14-006 B-7 Cut Set Report - LOOPGR 15 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 6.82E-7 100 Displaying 1663 Cut Sets. (1663 Original) 1 2.84E-8 4.16 IE-LOOPGR,AFW-PMP-CF-STRT,HPI-XHE-XM-FB 2

1.39E-8 2.04 IE-LOOPGR,AFW-MDP-TM-1A,AFW-TDP-FR-P2,EPS-DGN-TM-DGB,HPI-XHE-XM-FB 3

1.39E-8 2.04 IE-LOOPGR,AFW-MDP-TM-1B,AFW-TDP-FR-P2,EPS-DGN-TM-DGA,HPI-XHE-XM-FB 4

1.16E-8 1.70 IE-LOOPGR,AFW-MDP-CF-START,AFW-TDP-FR-P2,HPI-XHE-XM-FB 5

8.74E-9 1.28 IE-LOOPGR,AFW-TNK-FC-DWST,HPI-XHE-XM-FB 6

7.98E-9 1.17 IE-LOOPGR,AFW-MDP-TM-1A,AFW-TDP-FR-P2,EPS-DGN-FR-DGB,HPI-XHE-XM-FB 7

7.98E-9 1.17 IE-LOOPGR,AFW-MDP-TM-1B,AFW-TDP-FR-P2,EPS-DGN-FR-DGA,HPI-XHE-XM-FB 8

7.41E-9 1.09 IE-LOOPGR,AFW-MDP-TM-1A,AFW-TDP-FS-P2,EPS-DGN-TM-DGB,HPI-XHE-XM-FB 9

7.41E-9 1.09 IE-LOOPGR,AFW-MDP-TM-1B,AFW-TDP-FS-P2,EPS-DGN-TM-DGA,HPI-XHE-XM-FB Cut Set Report - LOOPGR 16-01-08 Only items contributing at least 1% to the total are displayed.

CCDP Total%

Cut Set 1.82E-7 100 Displaying 554 Cut Sets. (554 Original) 1 4.78E-9 2.63 IE-LOOPGR,ACP-BAC-LP-32U,EPS-DGN-TM-DGA,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 2 4.78E-9 2.63 IE-LOOPGR,ACP-BAC-LP-32T,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 3 3.25E-9 1.79 IE-LOOPGR,ACP-TFM-FC-34D21X,EPS-DGN-TM-DGA,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 4 3.25E-9 1.79 IE-LOOPGR,ACP-TFM-FC-34C31X,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 5 2.73E-9 1.51 IE-LOOPGR,ACP-BAC-LP-32T,EPS-DGN-FR-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 6 2.73E-9 1.51 IE-LOOPGR,ACP-BAC-LP-32U,EPS-DGN-FR-DGA,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 7 1.98E-9 1.09 IE-LOOPGR,CVC-MOV-OO-8512B,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 8 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,RHR-MOV-OO-8812A,SBO-DGN-ALIGN34C 9 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,RHR-MOV-OO-8812B,SBO-DGN-ALIGN34D 10 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,LPI-MOV-CC-8804A,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 11 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,LPI-MOV-CC-8804B,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 12 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,HPI-MOV-OO-8813,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D 13 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,HPI-MOV-OO-8814,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 14 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,HPI-MOV-OO-8920,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 15 1.98E-9 1.09 IE-LOOPGR,CVC-MOV-OO-8511A,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 16 1.98E-9 1.09 IE-LOOPGR,CVC-MOV-OO-8512A,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 17 1.98E-9 1.09 IE-LOOPGR,CVC-MOV-OO-8511B,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D

LER 336/14-006 B-8 CCDP Total%

Cut Set 18 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C,SWS-MOV-OO-50A 19 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D,SWS-MOV-OO-50B 20 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C,SWS-MOV-OO-71A 21 1.98E-9 1.09 IE-LOOPGR,EPS-DGN-TM-DGA,EPS-DGN-TM-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D,SWS-MOV-OO-71B 22 1.86E-9 1.02 IE-LOOPGR,ACP-TFM-FC-34C31X,EPS-DGN-FR-DGB,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34C 23 1.86E-9 1.02 IE-LOOPGR,ACP-TFM-FC-34D21X,EPS-DGN-FR-DGA,RCS-MDP-LK-BP1,/RCS-MDP-LK-BP2,SBO-DGN-ALIGN34D Referenced Events Event Description Probability ACP-BAC-LP-32R FAILURE OF 480V AC BUS 32R 3.33E-5 ACP-BAC-LP-32T FAILURE OF 480V AC BUS 32T 3.33E-5 ACP-BAC-LP-32U FAILURE OF 480V AC BUS 32U 3.33E-5 ACP-BAC-LP-32W FAILURE OF 480V AC BUS 32W 3.33E-5 ACP-BAC-LP-34C 4160 VAC BUS 34C FAILS 3.33E-5 ACP-BAC-LP-34D 4160 VAC BUS 34D FAILS 3.33E-5 ACP-TFM-CF-C3D2 CCF OF 4160/480V TRANSFORMERS 34C3-1X/34D2-1X 8.31E-7 ACP-TFM-FC-34C31X FAILURE OF 4160/480V TRANSFORMER 34C3-1X TO OPERATE 2.27E-5 ACP-TFM-FC-34C51X FAILURE OF 4160/480V TRANSFORMER 34C5-1X TO OPERATE 2.27E-5 ACP-TFM-FC-34D21X FAILURE OF 4160/480V TRANSFORMER 34D2-1X TO OPERATE 2.27E-5 ACP-TFM-FC-34D41X FAILURE OF 4160/480V TRANSFORMER 34D4-1X TO OPERATE 2.27E-5 AFW-MDP-CF-START CCF OF AFW MDPS TO START 4.76E-5 AFW-MDP-TM-1A AFW MDP UNAVAILABLE DUE TO TEST AND MAINTENANCE 3.98E-3 AFW-MDP-TM-1B AFW MDP UNAVAILABLE DUE TO TEST AND MAINTENANCE 3.98E-3 AFW-PMP-CF-STRT CCF OF AFW PUMPS TO START (EXCLUDING DRIVER) - PSA 1.42E-6 AFW-TDP-FR-P2 TURBINE DRIVEN FEED PUMP P2 FAILS TO RUN 1.22E-2 AFW-TDP-FS-P2 TURBINE DRIVEN FEED PUMP P2 FAILS TO START 6.49E-3 AFW-TDP-TM-P2 FEED PUMP P2 IS IN TEST OR MAINTENANCE 5.39E-3 AFW-TNK-FC-DWST DWST EXTERNAL LEAKAGE 4.37E-7 CCE-MDP-TM-P1A CCE MDP P1A UNAVAILABLE DUE TO TEST AND MAINTENANCE 7.12E-3 CCE-MDP-TM-P1B CCE MDP P1B UNAVAILABLE DUE TO TEST AND MAINTENANCE 7.12E-3 CCE-P3AOP-P3BSTBY CCE P1A IN OPERATION WHILE PUMP P1B IN STANDBY 5.00E-1 CCE-P3BOP-P3ASTBY CCE P1B IN OPERATION WHILE PUMP P1A IN STANDBY 5.00E-1 CCW-1A1BRUN-1CSTBY CCW MDP 1A RUNNING CCW MDP 1B RUNNING CCW MDP 1C STANDBY 9.95E-1 CVC-MDP-TM-P3A PUMP P3A IS IN TEST OR MAINTENANCE 3.88E-3 CVC-MDP-TM-P3B PUMP P3B IS IN TEST OR MAINTENANCE 3.88E-3 CVC-MOV-OO-8511A CHARGING PUMP TRAIN A MINFLOW MOV 8511A FAILS TO CLOSE 9.63E-4 CVC-MOV-OO-8511B CHARGING PUMP TRAIN B MINFLOW MOV 8511B FAILS TO CLOSE 9.63E-4 CVC-MOV-OO-8512A CHARGING PUMP TRAIN B MINFLOW MOV 8512A FAILS TO CLOSE 9.63E-4 CVC-MOV-OO-8512B CHARGING PUMP TRAIN A MINFLOW MOV 8512B FAILS TO CLOSE 9.63E-4 CVC-P3AOP-P3BSTBY CHARGING PUMP 3A IN OPERATION WHILE PUMP 3B IN STANDBY 5.00E-1 CVC-P3BOP-P3ASTBY CHARGING PUMP 3B IN OPERATION WHILE PUMP 3A IN STANDBY 5.00E-1

LER 336/14-006 B-9 Event Description Probability EPS-DGN-CF-RUN COMMON CAUSE FAILURE OF DIESEL GENERATORS TO RUN 1.12E-4 EPS-DGN-CF-RUN3 COMMON CAUSE FAILURE OF 3 DIESEL GENERATORS TO RUN 3.64E-5 EPS-DGN-CF-START3 COMMON CAUSE FAILURE OF 3 DIESEL GENERATORS TO START 1.14E-5 EPS-DGN-FR-DGA DIESEL GENERATOR A FAILS TO RUN 8.21E-3 EPS-DGN-FR-DGB DIESEL GENERATOR B FAILS TO RUN 8.21E-3 EPS-DGN-FR-SBO STATION BLACKOUT DIESEL FAILS TO RUN 8.21E-3 EPS-DGN-FS-DGA DIESEL GENERATOR A FAILS TO START 2.89E-3 EPS-DGN-FS-DGB DIESEL GENERATOR B FAILS TO START 2.89E-3 EPS-DGN-TM-DGA DG A UNAVAILABLE DUE TO TEST AND MAINTENANCE 1.43E-2 EPS-DGN-TM-DGB DG B UNAVAILABLE DUE TO TEST AND MAINTENANCE 1.43E-2 EPS-DGN-TM-SBO SBO DIESEL UNAVAILABLE DUE TO TEST AND MAINTENANCE 1.43E-2 EPS-XHE-XL-NR01H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR 8.71E-1 EPS-XHE-XM-SBO OPERATOR FAILS TO START & ALIGN SBO DIESEL 1.00E-2 HPI-MDP-TM-P1A HPI PUMP TRAIN P1A IS IN TEST OR MAINTENANCE 3.88E-3 HPI-MDP-TM-P1B HPI PUMP TRAIN P1B IS IN TEST OR MAINTENANCE 3.88E-3 HPI-MOV-OO-8813 SI PUMP MINFLOW VLV 8813 FAILS TO CLOSE 9.63E-4 HPI-MOV-OO-8814 SI PUMP MINFLOW VLV 8814 FAILS TO CLOSE 9.63E-4 HPI-MOV-OO-8920 SI PUMP MINFLOW VLV 8920 FAILS TO CLOSE 9.63E-4 HPI-XHE-XM-FB OPERATOR FAILS TO INITIATE FEED AND BLEED COOLING 2.00E-2 HPI-XHE-XM-RECIRC OPERATOR FAILS TO START HIGH PRESSURE RECIRC 2.00E-3 IE-LOOPGR LOSS OF OFFSITE POWER INITIATOR (GRID-RELATED) 1.00E+0 LPI-MOV-CC-8804A LPSI TO SI ISOLN VALVE 8804A FAILS TO OPEN 9.63E-4 LPI-MOV-CC-8804B LPSI TO SI ISOLN VALVE 8804B FAILS TO OPEN 9.63E-4 NOTWINTER NOT WINTER OPERATION (SUMMER TIME) 7.50E-1 PPR-SRV-OO-455A PORV 455A FAILS TO RECLOSE AFTER OPENING 5.80E-3 PPR-SRV-OO-456 PORV 456 FAILS TO RECLOSE AFTER OPENING 4.80E-3 RCS-MDP-LK-BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING OPEN) FAILS 1.25E-2 RCS-MDP-LK-BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING OPEN) FAILS 2.00E-1 RHR-MOV-OO-8812A RHR PUMP P1A RWST SUCTN VLV 8812A FAILS TO CLOSE (INTERLOCK W/ 8837/8A) 9.63E-4 RHR-MOV-OO-8812B RHR PUMP P1B RWST SUCTN VLV 8812B FAILS TO CLOSE (INTERLOCK W/ 8837/8B) 9.63E-4 SBO-DGN-ALIGN34C SBO DIESEL GENERATOR ALIGNED TO BUS 34C 1.00E+0 SBO-DGN-ALIGN34D SBO DIESEL GENERATOR ALIGNED TO BUS 34D 1.00E+0 SWS-1ARUN-1CSTBY SWS MDP 1A RUNNING SWS MDP 1C STANDBY 5.00E-1 SWS-1BRUN-1DSTBY SWS MDP 1B RUNNING SWS MDP 1D STANDBY 5.00E-1 SWS-1CRUN-1ASTBY SWS MDP 1C RUNNING SWS MDP 1A STANDBY 5.00E-1 SWS-1DRUN-1BSTBY SWS MDP 1D RUNNING SWS MDP 1B STANDBY 5.00E-1 SWS-FAN-CF-HVY2ABS CCF OF SWS VENTILLATION FANS TO START 2.11E-5 SWS-MDP-CF-START PUMPS FAIL FROM COMMON CAUSE TO START 1.95E-6 SWS-MOV-OO-50A COMPONENT COOLING WATER ISOLATION VLV FAILS TO CLOSE 9.63E-4 SWS-MOV-OO-50B COMPONENT COOLING WATER ISOLATION VLV FAILS TO CLOSE 9.63E-4 SWS-MOV-OO-71A TBCCW ISOLATION VALVE FAILS TO CLOSE 9.63E-4 SWS-MOV-OO-71B TBCCW ISOLATION VALVE FAILS TO CLOSE 9.63E-4 SWS-XHE-XL-VENT OPERATOR FAILS TO PROVIDE ALTERNATE VENTILATION TO SWS 1.00E-2

LER 336/14-006 C-1 Appendix C: Key Event Trees Figure C-1. Millstone Power Station Unit 2, LOOP Event Tree.

IE-LOOP LOSS OF OFFSITE POWER RPS REACTOR PROTECTION SYSTEM FTF-SBO EPS EMERGENCY POWER AFW AUXILIARY FEEDWATER SYSTEM PORV PORVs ARE CLOSED LOSC LOSS OF ALL SEAL COOLING HPI HIGH PRESSURE INJECTION OTC ONCE THROUGH COOLING OPR-02H OFFSITE POWER RECOVERY IN 2 HRS OPR-06H OFFSITE POWER RECOVERY IN 6 HRS SSC SECONDARY SIDE COOLDOWN SYS-FLAG-LOSP SDC SHUTDOWN COOLING FTF-RECIRC HPR HIGH PRESSURE RECIRCULATION SYS-FLAG-LOSP CSR CONTAINMENT COOLING End State (Phase - CD) 1 OK LOSC-L 2

LOOP-1 PORV-L 3

OK 4

OK 5

CD 6

CD TRUE 7

OK 8

CD 9

CD 10 OK CSR-L 11 CD HPR-L 12 CD HPI-L 13 CD AFW-L 14 OK 15 OK 16 CD 17 CD 18 OK CSR-L 19 CD HPR-L 20 CD OTC-L 21 CD 22 SBO 23 ATWS 24 CD

LER 336/14-006 C-2 Figure C-2. Millstone Power Station Unit 2, SBO Event Tree.

FTF-SBO EPS EMERGENCY POWER FTF-SBO EPS-SBO STATION BLACKOUT POWER FTF-SBO AFW-B MILLSTONE 2 AUXILIARY FEEDWATER USING SBO-FTF FLAG SET PORV PORVs ARE CLOSED CBO CONTROLLED BLEEDOFF ISOLATED RSUB REACTOR COOLANT SUBCOOLING MAINTAINED RCPSI RCP SEAL INTEGRITY MAINTAINED OPR-08H OFFSITE POWER RECOVERY IN 8 HRS DGR-08H DIESEL GENERATOR RECOVERY IN 8 HOURS End State (Phase - CD) 1 LOOP-1 2

OK 3

OK 4

SBO-3 RCPSI01 5

SBO-1 OPR-01H 6

OK DGR-01H 7

CD 8

OK 9

OK 10 SBO-3 RCPSI02 11 SBO-1 OPR-01H 12 OK DGR-01H 13 CD 14 OK 15 OK 16 SBO-3 RCPSI03 17 SBO-1 OPR-01H 18 OK DGR-01H 19 CD 20 OK 21 OK 22 SBO-3 RCPSI04 23 SBO-1 OPR-01H 24 OK DGR-01H 25 CD PORV-B 26 SBO-1 OPR-01H 27 OK DGR-01H 28 CD 29 SBO-2 OPR-01H 30 OK DGR-01H 31 CD

LER 336/14-006 C-3 Figure C-3. Millstone Power Station Unit 3, Grid-Related LOOP Event Tree.

IE-LOOPGR LOSS OF OFFSITE POWER INITIATOR (GRID-RELATED)

FTF-LOOP RPS-L REACTOR TRIP FTF-SBO EPS EMERGENCY POWER AFW AUXILIARY FEEDWATER SYSTEM PORV PORVs ARE CLOSED LOSC RCP SEAL COOLING MAINTAINED HPI HIGH PRESSURE INJECTION FAB FEED AND BLEED OPR-02H OFFSITE POWER RECOVERY IN 2 HRS OPR-06H OFFSITE POWER RECOVERY IN 6 HRS SSC SECONDARY SIDE COOLDOWN RHR RESIDUAL HEAT REMOVAL FTF-RECIRC HPR HIGH PRESSURE RECIRC End State (Phase - CD) 1 OK LOSC-L 2

LOOP-1 PORV-L 3

OK 4

OK 5

CD 6

OK 7

CD 8

OK HPR-L 9

CD HPI-L 10 CD AFW-L 11 OK 12 CD 13 OK HPR-L 14 CD FAB-L 15 CD 16 SBO 17 ATWS 18 CD

LER 336/14-006 C-4 Figure C-4. Millstone Power Station Unit 3, SBO Event Tree.

FTF-SBO EPS EMERGENCY POWER EPS-SBO STATION BLACKOUT POWER FTF-SBO AFW-B AUXILIARY FEEDWATER SYSTEM DURING SBO PORV PORVs ARE CLOSED RSD RAPID SECONDARY DEPRESS BP1 RCP SEAL STAGE 1 INTEGRITY O1 RCP SEAL STAGE 1 INTEGRITY BP2 RCP SEAL STAGE 2 INTEGRITY O2 RCP SEAL STAGE 2 INTEGRITY OPR-08H OFFSITE POWER RECOVERY (IN 8 HR)

DGR-08H DIESEL GENERATOR RECOVERY (IN 8 HR)

End State (Phase - CD) 1 LOOP-1 21 gpm/rcp 2

OK 3

OK 4

SBO-4 182 gpm/rcp 5

SBO-1 OPR-04H 6

OK DGR-04H 7

CD 76 gpm/rcp 8

SBO-1 9

OK 10 SBO-4 480 gpm/rcp 11 SBO-1 OPR-02H 12 OK DGR-02H 13 CD 21 gpm/rcp 14 SBO-2 15 OK 16 SBO-4 172 gpm/rcp 17 SBO-2 OPR-03H 18 OK DGR-03H 19 CD 182 gpm/rcp 20 SBO-2 OPR-03H 21 OK DGR-03H 22 CD 61 gpm/rcp 23 SBO-2 OPR-06H 24 OK DGR-06H 25 CD 300 gpm/rcp 26 SBO-2 OPR-02H 27 OK DGR-02H 28 CD 300 gpm/rcp 29 SBO-2 OPR-02H 30 OK DGR-02H 31 CD 76 gpm/rcp 32 SBO-2 OPR-06H 33 OK DGR-06H 34 CD 300 gpm/rcp 35 SBO-2 OPR-02H 36 OK DGR-02H 37 CD 480 gpm/rcp 38 SBO-2 OPR-02H 39 OK DGR-02H 40 CD PORV-B 41 SBO-2 OPR-01H 42 OK DGR-01H 43 CD AFW-B 44 SBO-3 OPR-01H 45 OK DGR-01H 46 CD