ML16138A334

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ASP Analysis - Reject Perry Nuclear Power Plant, Unit 1 (440-2014-005)
ML16138A334
Person / Time
Site: Perry FirstEnergy icon.png
Issue date: 05/17/2016
From:
Office of Nuclear Regulatory Research
To:
FirstEnergy Nuclear Operating Co
References
IR 2014005, IR 2015003, LER 14-005-00
Download: ML16138A334 (8)
v • d • e


Text

ASP Analysis - REJECT Accident Sequence Precursor Program - Office of Nuclear Regulatory Research Perry Nuclear Power Loss of Feedwater Results in Automatic Reactor Protection Plant, Unit 1 System Actuation Event Date: 11/7/2014 LER: 440-2014-005 IR: 50-440/2014-005 and 50-440/15-003 Plant Type: General Electric BWR/6 with Wet MARK III Containment Plant Operating Mode (Reactor Power Level): Mode 1 (99 Percent Reactor Power)

Analyst: Reviewer: Contributors: BC Approved Date:

Keith Tetter David Aird N/A 4/5/2016 Event Description. On November 7, 2014 at 8:47 am, an automatic reactor scram occurred due to a Reactor Protection System (RPS) actuation in response to a low reactor water level (Level 3) signal caused by a loss of feedwater flow (A and B turbine-driven reactor feedwater pumps (RFPs) to the Reactor Pressure Vessel (RPV)). The loss of feedwater was a result of an invalid feedwater signal from the redundant reactivity control system (RRCS). All control rods fully inserted into the core.

RPV water level continued to decrease to the Level 2 setpoint (130 inches above the top of active fuel (TAF)) when the Reactor Core Isolation Cooling (RCIC) and High Pressure Core Spray (HPCS) systems started and injected into the RPV. Balance-of-plant isolation occurred with isolation of all required valves and both reactor recirculation pumps tripped as designed. The division 3 emergency diesel generator, which supplies emergency electrical power to the HPCS system started but, as designed, did not load onto the bus. The motor-driven RFP started as designed on a RFP trip signal.

At approximately 8:50 am, the HPCS and RCIC system injections terminated on a Level 8 setpoint (219 inches above the TAF) as designed. The lowest RPV water level reached during the event was 77.2 inches above the TAF and the RPS was reset at 9:15 am. Mode 4 (Cold Shutdown) was entered at 5:52 pm when the average reactor coolant temperature decreased to 200 degrees Fahrenheit.

Cause. The RPS scram was caused by an invalid feedwater runback signal from the division 1 RRCS. The root cause was determined to be a latent design flaw in the upgrade design package of the digital feedwater control system (DFWCS) modification in 2005. Due to implementing the new digital upgrade, the interface between RRCS and DFWCS involving the runback signal was altered.

The original design used interposing relays as the interface between the RRCS and the feedwater control system. The digital upgrade changed the design interface and removed the interposing relays tying the output of RRCS directly into DFWCS.

IR Summary/SDP Result. In Inspection Report (IR) 50-440/2014-005, the inspectors identified a Green self-revealing finding for the licensees failure to establish and maintain a correct surveillance inspection procedure for RRCS channel checks. Also in IR 50-440/2014-005, the inspectors identified a Green self-revealing finding for the licensees failure to complete a Regulatory Applicability Determination (RAD) specified in a procedure. In this case, the licensee made changes to the RRCS, including blocking inputs to the DFWCS runback function and disabling the RRCS self-test for both divisions of RRCS. These changes would likely have been subject to additional review had the RAD been completed. In IR 50-440/2015-003, the inspectors reviewed a licensee-identified violation of 10 CFR 50, Appendix B, Criterion III that a latent design flaw existed in the DFWCS design package.

The inspectors evaluated the issue and determined the safety significance of the event was very low.

The LER was closed in IR 50-440/2015-003.

1

LER 440-2014-005 Modeling Assumptions. The Perry Standardized Plant Analysis Risk (SPAR) model, Revision 8.19, created in May 2014, was used for this analysis. Results of the risk analysis are included at the end of this report as Appendix A. The following modeling assumptions were made for the analysis of this initiating event:

  • The probability of IE-LOMFW (Loss of Main Feedwater Initiating Event) was set to 1.0 and all other initiating event probabilities were set to zero.
  • All safety systems responded as designed.

SPAR Model Modifications. No SPAR model modifications were needed to conduct this analysis.

Rejection Basis. The conditional core damage probability (CCDP) for this analysis with the loss of feedwater initiating event is 6.8x10-8. This is less than the ASP Program threshold of 1x10-6.

Therefore, this event is not a precursor and is screened out of the ASP Program.

Dominant Sequence. The dominant accident sequence is LOMFW Sequence 30 (CCDP = 1.9x10-8) which contributes approximately 29% of the total internal events CCDP. The cut sets/sequences that contribute to the top 95% and/or at least 1% of the total internal events CCDP are provided in Appendix A.

The events and important component failures in LOMFW Sequence 30 are:

  • Suppression Pool Cooling failed
  • Power Conversion System is unavailable (feedwater or condenser)
  • Containment Venting failed
  • Late Injection failed 2

LER 440-2014-005 Appendix A: SAPHIRE 8 Worksheet Summary of Conditional Event Changes Event Description Cond Value Nominal Value IE-LOMFW LOSS OF FEEDWATER a 6.89E-2 1.00E+0

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 LOMFW 30 1.94E-8 28.6% /RPS, /SRV, CND, /MFW, SPC, CSS, PCSR, CVS, LI03 LOMFW 23 1.32E-8 19.5% /RPS, /SRV, /CND, MFW, RCI, HCS, DEP LOMFW 77-26 1.19E-8 17.5% RPS, /PPR, RPT LOMFW 22 9.04E-9 13.3% /RPS, /SRV, /CND, MFW, RCI, HCS, /DEP, LPI, VA LOMFW 77-04 7.67E-9 11.3% RPS, /PPR, /RPT, /PCS01, SLC LOMFW 77-02 2.44E-9 3.6% RPS, /PPR, /RPT, /PCS01, /SLC, /INH, LVL LOMFW 77-03 2.44E-9 3.6% RPS, /PPR, /RPT, /PCS01, /SLC, INH Total 6.77E-8 100.0%

Referenced Fault Trees Fault Tree Description CND MAIN CONDENSER CSS CONTAINMENT SPRAY CVS CONTAINMENT VENTING DEP MANUAL REACTOR DEPRESS HCS HPCS INH INHIBIT ADS/ HPCS LI03 PERRY LATE INJECTION FAULT TREE LPI LOW PRESSURE INJECTION LVL PREVENT OVERFILL MFW FEEDWATER PCSR POWER CONVERSION SYSTEM RECOVERY RCI RCIC RPS REACTOR SHUTDOWN RPT RECIRC PUMP TRIP SLC STANDBY LIQUID CONTROL SPC SUPPRESSION POOL COOLING VA ALTERNATE LOW PRESS INJECTION Cut Set Report - LOMFW 30 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET 1.94E-8 100 Displaying 11 Cut Sets. (11 Original) 1 1.50E-8 77.27 IE-LOMFW,CV05,CVS-XHE-XM-VENT1,MSS-TBV-CC-BYPAS,PCS-XHE-XL-LTLOFW,RHR-XHE-XM-ERROR 2 4.28E-9 22.08 IE-LOMFW,CV03,CVS-XHE-XM-VENT1,MSS-TBV-CC-BYPAS,PCS-XHE-XL-LTLOFW,RHR-XHE-XM-ERROR A-1

LER 440-2014-005 Cut Set Report - LOMFW 23 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET 1.32E-8 100 Displaying 209 Cut Sets. (209 Original) 1 1.87E-9 14.18 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 2 9.63E-10 7.30 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 3 7.14E-10 5.41 IE-LOMFW,ADS-XHE-XM-MDEPR,DCP-BAT-TM-U1BOP1,ESW-MDP-TM-PUMPC,RCI-TDP-FR-PUMP 4 4.24E-10 3.21 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MOV-FT-SUCTR,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 5 3.68E-10 2.79 IE-LOMFW,ADS-XHE-XM-MDEPR,DCP-BAT-TM-U1BOP1,HCS-MDP-TM-HPCS,RCI-TDP-FR-PUMP 6 3.58E-10 2.71 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-FS-MDFWP,RCI-TDP-FR-PUMP 7 3.06E-10 2.32 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-TM-MDFWP,RCI-TDP-FS-PUMP 8 2.63E-10 1.99 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,PCS-XHE-XO-ERROR,RCI-TDP-FR-PUMP 9 2.50E-10 1.89 IE-LOMFW,ADS-XHE-XM-MDEPR,CDS-AOV-CC-MKUP1,ESW-MDP-TM-PUMPC,RCI-TDP-FR-PUMP 10 2.50E-10 1.89 IE-LOMFW,ADS-XHE-XM-MDEPR,CDS-AOV-CC-MKUP2,ESW-MDP-TM-PUMPC,RCI-TDP-FR-PUMP 11 2.18E-10 1.66 IE-LOMFW,ADS-XHE-XM-MDEPR,CDS-TNK-HW-CST 12 1.92E-10 1.46 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-FS-PUMPC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 13 1.84E-10 1.40 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,MFW-MDP-FS-MDFWP,RCI-TDP-FR-PUMP 14 1.62E-10 1.23 IE-LOMFW,ADS-XHE-XM-MDEPR,DCP-BAT-TM-U1BOP1,HCS-MOV-FT-SUCTR,RCI-TDP-FR-PUMP 15 1.58E-10 1.20 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,MFW-MDP-TM-MDFWP,RCI-TDP-FS-PUMP 16 1.41E-10 1.07 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPA,HCS-MOV-FT-SUCTR,MFW-MDP-TM-MDFWP 17 1.41E-10 1.07 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-TM-MDFWP,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 18 1.41E-10 1.07 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-XHE-XR-TRNC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 19 1.36E-10 1.03 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MOV-CC-INJEC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 20 1.36E-10 1.03 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MOV-CC-F140,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 21 1.35E-10 1.03 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,PCS-XHE-XO-ERROR,RCI-TDP-FR-PUMP 22 1.34E-10 1.01 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-FS-HPCS,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP Cut Set Report - LOMFW 77-26 Only items contributing at least 1% to the total are displayed.
  1. CCDP TOTAL% CUT SET 1.19E-8 100 Displaying 10 Cut Sets. (10 Original) 1 4.07E-9 34.30 IE-LOMFW,RPS-SYS-FC-PSOVS,RRS-CRB-CC-PUMP2 2 4.07E-9 34.30 IE-LOMFW,RPS-SYS-FC-PSOVS,RRS-CRB-CC-PUMP1 3 9.09E-10 7.67 IE-LOMFW,RPS-SYS-FC-RELAY,RRS-CRB-CC-PUMP2 4 9.09E-10 7.67 IE-LOMFW,RPS-SYS-FC-RELAY,RRS-CRB-CC-PUMP1 5 5.98E-10 5.04 IE-LOMFW,RPS-SYS-FC-CRD,RRS-CRB-CC-PUMP2 6 5.98E-10 5.04 IE-LOMFW,RPS-SYS-FC-CRD,RRS-CRB-CC-PUMP1 7 2.63E-10 2.22 IE-LOMFW,RPS-SYS-FC-HCU,RRS-CRB-CC-PUMP2 8 2.63E-10 2.22 IE-LOMFW,RPS-SYS-FC-HCU,RRS-CRB-CC-PUMP1 A-2

LER 440-2014-005 Cut Set Report - LOMFW 22 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET 9.04E-9 100 Displaying 74 Cut Sets. (74 Original) 1 1.63E-9 18.05 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-XHE-XM-ERROR,RHR-STR-CF-NLOCA,SPCAI 2 1.42E-9 15.68 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,RHR-STR-CF-NLOCA,SPCAI 3 9.08E-10 10.05 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MOV-CF-F130AB,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,SPCAI 4 7.89E-10 8.73 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MOV-CF-F130AB,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,SPCAI 5 6.09E-10 6.73 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MDP-CF-START,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,SPCAI 6 5.29E-10 5.85 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MDP-CF-START,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,SPCAI 7 2.56E-10 2.84 IE-LOMFW,CTS-XHE-XM-ERROR,FWS-XHE-XM-ERROR,MFW-MDP-TM-MDFWP,RHR-STR-CF-NLOCA,SPCAI 8 2.23E-10 2.46 IE-LOMFW,CTS-XHE-XM-ERROR,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,MFW-MDP-TM-MDFWP,RHR-STR-CF-NLOCA,SPCAI 9 1.96E-10 2.16 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-EDP-TM-PUMP,FWS-XHE-XL-PMPR,RHR-STR-CF-NLOCA,SPCAI 10 1.43E-10 1.58 IE-LOMFW,CTS-XHE-XM-ERROR,ESW-MOV-CF-F130AB,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,MFW-MDP-TM-MDFWP,SPCAI 11 1.39E-10 1.53 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-EDP-FS-PUMP,FWS-XHE-XL-PMPR,RHR-STR-CF-NLOCA,SPCAI 12 1.24E-10 1.37 IE-LOMFW,CTS-XHE-XM-ERROR,ESW-MOV-CF-F130AB,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,MFW-MDP-TM-MDFWP,SPCAI 13 1.09E-10 1.20 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MOV-CF-F130AB,FWS-EDP-TM-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,SPCAI 14 9.56E-11 1.06 IE-LOMFW,CTS-XHE-XM-ERROR,ESW-MDP-CF-START,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,MFW-MDP-TM-MDFWP,SPCAI 15 9.44E-11 1.04 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MDP-CF-RUN,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,SPCAI Cut Set Report - LOMFW 77-04 Only items contributing at least 1% to the total are displayed.
  1. CCDP TOTAL% CUT SET 7.67E-9 100 Displaying 20 Cut Sets. (20 Original) 1 3.40E-9 44.35 IE-LOMFW,RPS-SYS-FC-PSOVS,SLC-XHE-XM-ERROR 2 1.70E-9 22.17 IE-LOMFW,RPS-SYS-FC-PSOVS,SLC-XHE-XR-SLCS 3 7.60E-10 9.91 IE-LOMFW,RPS-SYS-FC-RELAY,SLC-XHE-XM-ERROR 4 5.00E-10 6.52 IE-LOMFW,RPS-SYS-FC-CRD,SLC-XHE-XM-ERROR 5 3.80E-10 4.96 IE-LOMFW,RPS-SYS-FC-RELAY,SLC-XHE-XR-SLCS 6 2.50E-10 3.26 IE-LOMFW,RPS-SYS-FC-CRD,SLC-XHE-XR-SLCS 7 2.20E-10 2.87 IE-LOMFW,RPS-SYS-FC-HCU,SLC-XHE-XM-ERROR 8 1.10E-10 1.43 IE-LOMFW,RPS-SYS-FC-HCU,SLC-XHE-XR-SLCS 9 1.09E-10 1.42 IE-LOMFW,RPS-SYS-FC-PSOVS,SLC-EPV-CF-F004AB Cut Set Report - LOMFW 77-02 Only items contributing at least 1% to the total are displayed.
  1. CCDP TOTAL% CUT SET Total 2.44E-9 100 Displaying 4 Cut Sets. (4 Original) 1 1.70E-9 69.67 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-PSOVS 2 3.80E-10 15.57 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-RELAY 3 2.50E-10 10.25 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-CRD 4 1.10E-10 4.51 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-HCU A-3

LER 440-2014-005 Cut Set Report - LOMFW 77-03 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET Total 2.44E-9 100 Displaying 4 Cut Sets. (4 Original) 1 1.70E-9 69.67 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-PSOVS 2 3.80E-10 15.57 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-RELAY 3 2.50E-10 10.25 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-CRD 4 1.10E-10 4.51 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-HCU Referenced Events Event Description Probability ADS-XHE-XM-MDEPR OPERATOR FAILS TO DEPRESSURIZE THE REACTOR 5.00E-4 CDS-AOV-CC-MKUP1 MAKEUP PATH 1 FAILS 9.51E-4 CDS-AOV-CC-MKUP2 MAKEUP PATH 2 FAILS 9.51E-4 CDS-TNK-HW-CST CONDENSATE STORAGE TANK FAILS 4.37E-7 CTS-XHE-XM-ERROR OPERATOR FAILS TO ALIGN CONDENSATE TRANSFER ALTERNATE INJECTION 6.00E-2 CV03 CONTAINMENT FAILURE CAUSES LOSS OF INJECTION 4.00E-2 CV05 CONTAINMENT FAILURE CAUSES LOSS OF INJECTION 1.40E-1 CVS-XHE-XM-VENT1 OPERATOR FAILS TO VENT CONTAINMENT (DEP EVT) 5.09E-2 DCP-BAT-TM-U1BOP1 UNIT 1 BOP BATTERY D-1-B IS IN TEST OR MAINTENANCE 2.72E-3 ESW-MDP-CF-RUN ESW PUMPS FAIL FROM COMMON CAUSE TO RUN 5.78E-7 ESW-MDP-CF-START ESW PUMPS FAIL FROM COMMON CAUSE TO START 3.73E-6 ESW-MDP-FS-PUMPC ESW PUMP 1P45-C002 FAILS TO START 1.36E-3 ESW-MDP-TM-PUMPA ESW PUMP 1P45-C001A IS IN TEST OR MAINTENANCE 1.32E-2 ESW-MDP-TM-PUMPC ESW PUMP 1P45-C002 IS IN TEST OR MAINTENANCE 1.32E-2 ESW-MOV-CC-F140 ESW PUMP C DISCH MOV F140 FAILS TO OPEN 9.63E-4 ESW-MOV-CF-F130AB ESW MOVS F130A, B FAIL FROM COMMON CAUSE 5.56E-6 ESW-XHE-XR-TRNC ESW TRAIN C NOT RESTORED AFTER MAINTENANCE 1.00E-3 FWS-EDP-FR-PUMP FIREWATER PUMP FAILS TO RUN 5.21E-2 FWS-EDP-FS-PUMP FIREWATER PUMP FAILS TO START 5.09E-3 FWS-EDP-TM-PUMP DIESEL FIREWATER PUMP UNAVAILABLE BECAUSE OF MAINTENANCE 7.19E-3 FWS-XHE-XL-PMPR OFFSITE PUMPER TRUCK FAILS TO ARRIVE AND PROVIDE WATER 1.00E+0 FWS-XHE-XM-ERROR OPERATOR FAILS TO ALIGN FIREWATER INJECTION 6.00E-2 HCS-MDP-FS-HPCS HPCS PUMP FAILS TO START 9.47E-4 HCS-MDP-TM-HPCS HPCI TRAIN IS UNAVAILABLE BECAUSE OF MAINTENANCE 6.82E-3 HCS-MOV-CC-INJEC HPCS INJECTION VALVE FAILS TO OPEN 9.63E-4 HCS-MOV-FT-SUCTR HPCS SUCTION TRANSFER FAILS 3.00E-3 IE-LOMFW LOSS OF FEEDWATER 1.00E+0 LCS-XHE-XL-RCOOL OPERATOR FAILS TO RECOVER ROOM COOLING 1.00E+0 MFW-MDP-FS-MDFWP FEEDWATER PUMP 1N27-C004 FAILS TO START 1.36E-3 MFW-MDP-TM-MDFWP FEEDWATER PUMP 1N27-C004 IS IN TEST OR MAINTENANCE 7.12E-3 MSS-TBV-CC-BYPAS TURBINE BYPASS VALVES FAIL TO OPEN 4.20E-3 OPR-XHE-XM-ADSINHIB OPERATOR FAILS TO INHIBIT ADS AND CONTROL LVL 1.00E-3 OPR-XHE-XM-NOOVRFIL OPERATOR FAILS TO CONTROL LEVEL 1.00E-3 PCS-XHE-XL-LTLOFW OPERATOR FAILS TO RECOVER THE MAIN CONDENSER 1.00E+0 PCS-XHE-XO-ERROR OPERATOR FAILS TO MAINTAIN FEEDWATER INJECTION 1.00E-3 RCI-RESTART RESTART OF RCIC IS REQUIRED 1.50E-1 RCI-TDP-FR-PUMP RCIC PUMP FAILS TO RUN GIVEN THAT IT STARTED 3.97E-2 RCI-TDP-FS-PUMP RCIC PUMP FAILS TO START 6.49E-3 RCI-TDP-FS-RSTRT RCIC FAILS TO RESTART GIVEN START AND SHORT-TERM RUN 8.00E-2 RCI-XHE-XL-RSTRT OPERATOR FAILS TO RECOVER RCIC FAILURE TO RESTART 2.50E-1 RHR-STR-CF-NLOCA SUPPRESSION POOL STRAINERS FAIL FROM COMMON CAUSE (NON-LOCA) 1.00E-5 RHR-XHE-XM-ERROR OPERATOR FAILS TO START/CONTROL RHR 5.00E-4 RPS-SYS-FC-CRD CONTROL ROD DRIVE MECHANICAL FAILURE 2.50E-7 RPS-SYS-FC-HCU HCU COMPONENTS FAIL 1.10E-7 A-4

LER 440-2014-005 RPS-SYS-FC-PSOVS HCU SCRAM PILOT SOVS FAIL 1.70E-6 RPS-SYS-FC-RELAY TRIP SYSTEM RELAYS FAIL 3.80E-7 RRS-CRB-CC-PUMP1 RECIRC PUMP 1 FIELD BREAKER FAILS TO OPEN 2.39E-3 RRS-CRB-CC-PUMP2 RECIRC PUMP 2 FIELD BREAKER FAILS TO OPEN 2.39E-3 SLC-EPV-CF-F004AB SLC SQUIB VALVES FAIL FROM COMMON CAUSE 6.43E-5 SLC-XHE-XM-ERROR OPERATOR FAILS START/CONTROL SLC 2.00E-3 SLC-XHE-XR-SLCS OPERATOR FAILS TO RESTORE SLCS AFTER MAINTENANCE 1.00E-3 SPCAI SUPPRESSION POOL CLEANUP ALTERNATE INJECTION IS UNAVAILABLE 1.00E+0 A-5

LER 440-2014-005 Appendix B: Key Event Tree Figure B-1: Perry, Unit 1 LOMFW Event Tree B-1

ASP Analysis - REJECT Accident Sequence Precursor Program - Office of Nuclear Regulatory Research Perry Nuclear Power Loss of Feedwater Results in Automatic Reactor Protection Plant, Unit 1 System Actuation Event Date: 11/7/2014 LER: 440-2014-005 IR: 50-440/2014-005 and 50-440/15-003 Plant Type: General Electric BWR/6 with Wet MARK III Containment Plant Operating Mode (Reactor Power Level): Mode 1 (99 Percent Reactor Power)

Analyst: Reviewer: Contributors: BC Approved Date:

Keith Tetter David Aird N/A 4/5/2016 Event Description. On November 7, 2014 at 8:47 am, an automatic reactor scram occurred due to a Reactor Protection System (RPS) actuation in response to a low reactor water level (Level 3) signal caused by a loss of feedwater flow (A and B turbine-driven reactor feedwater pumps (RFPs) to the Reactor Pressure Vessel (RPV)). The loss of feedwater was a result of an invalid feedwater signal from the redundant reactivity control system (RRCS). All control rods fully inserted into the core.

RPV water level continued to decrease to the Level 2 setpoint (130 inches above the top of active fuel (TAF)) when the Reactor Core Isolation Cooling (RCIC) and High Pressure Core Spray (HPCS) systems started and injected into the RPV. Balance-of-plant isolation occurred with isolation of all required valves and both reactor recirculation pumps tripped as designed. The division 3 emergency diesel generator, which supplies emergency electrical power to the HPCS system started but, as designed, did not load onto the bus. The motor-driven RFP started as designed on a RFP trip signal.

At approximately 8:50 am, the HPCS and RCIC system injections terminated on a Level 8 setpoint (219 inches above the TAF) as designed. The lowest RPV water level reached during the event was 77.2 inches above the TAF and the RPS was reset at 9:15 am. Mode 4 (Cold Shutdown) was entered at 5:52 pm when the average reactor coolant temperature decreased to 200 degrees Fahrenheit.

Cause. The RPS scram was caused by an invalid feedwater runback signal from the division 1 RRCS. The root cause was determined to be a latent design flaw in the upgrade design package of the digital feedwater control system (DFWCS) modification in 2005. Due to implementing the new digital upgrade, the interface between RRCS and DFWCS involving the runback signal was altered.

The original design used interposing relays as the interface between the RRCS and the feedwater control system. The digital upgrade changed the design interface and removed the interposing relays tying the output of RRCS directly into DFWCS.

IR Summary/SDP Result. In Inspection Report (IR) 50-440/2014-005, the inspectors identified a Green self-revealing finding for the licensees failure to establish and maintain a correct surveillance inspection procedure for RRCS channel checks. Also in IR 50-440/2014-005, the inspectors identified a Green self-revealing finding for the licensees failure to complete a Regulatory Applicability Determination (RAD) specified in a procedure. In this case, the licensee made changes to the RRCS, including blocking inputs to the DFWCS runback function and disabling the RRCS self-test for both divisions of RRCS. These changes would likely have been subject to additional review had the RAD been completed. In IR 50-440/2015-003, the inspectors reviewed a licensee-identified violation of 10 CFR 50, Appendix B, Criterion III that a latent design flaw existed in the DFWCS design package.

The inspectors evaluated the issue and determined the safety significance of the event was very low.

The LER was closed in IR 50-440/2015-003.

1

LER 440-2014-005 Modeling Assumptions. The Perry Standardized Plant Analysis Risk (SPAR) model, Revision 8.19, created in May 2014, was used for this analysis. Results of the risk analysis are included at the end of this report as Appendix A. The following modeling assumptions were made for the analysis of this initiating event:

  • The probability of IE-LOMFW (Loss of Main Feedwater Initiating Event) was set to 1.0 and all other initiating event probabilities were set to zero.
  • All safety systems responded as designed.

SPAR Model Modifications. No SPAR model modifications were needed to conduct this analysis.

Rejection Basis. The conditional core damage probability (CCDP) for this analysis with the loss of feedwater initiating event is 6.8x10-8. This is less than the ASP Program threshold of 1x10-6.

Therefore, this event is not a precursor and is screened out of the ASP Program.

Dominant Sequence. The dominant accident sequence is LOMFW Sequence 30 (CCDP = 1.9x10-8) which contributes approximately 29% of the total internal events CCDP. The cut sets/sequences that contribute to the top 95% and/or at least 1% of the total internal events CCDP are provided in Appendix A.

The events and important component failures in LOMFW Sequence 30 are:

  • Suppression Pool Cooling failed
  • Power Conversion System is unavailable (feedwater or condenser)
  • Containment Venting failed
  • Late Injection failed 2

LER 440-2014-005 Appendix A: SAPHIRE 8 Worksheet Summary of Conditional Event Changes Event Description Cond Value Nominal Value IE-LOMFW LOSS OF FEEDWATER a 6.89E-2 1.00E+0

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 LOMFW 30 1.94E-8 28.6% /RPS, /SRV, CND, /MFW, SPC, CSS, PCSR, CVS, LI03 LOMFW 23 1.32E-8 19.5% /RPS, /SRV, /CND, MFW, RCI, HCS, DEP LOMFW 77-26 1.19E-8 17.5% RPS, /PPR, RPT LOMFW 22 9.04E-9 13.3% /RPS, /SRV, /CND, MFW, RCI, HCS, /DEP, LPI, VA LOMFW 77-04 7.67E-9 11.3% RPS, /PPR, /RPT, /PCS01, SLC LOMFW 77-02 2.44E-9 3.6% RPS, /PPR, /RPT, /PCS01, /SLC, /INH, LVL LOMFW 77-03 2.44E-9 3.6% RPS, /PPR, /RPT, /PCS01, /SLC, INH Total 6.77E-8 100.0%

Referenced Fault Trees Fault Tree Description CND MAIN CONDENSER CSS CONTAINMENT SPRAY CVS CONTAINMENT VENTING DEP MANUAL REACTOR DEPRESS HCS HPCS INH INHIBIT ADS/ HPCS LI03 PERRY LATE INJECTION FAULT TREE LPI LOW PRESSURE INJECTION LVL PREVENT OVERFILL MFW FEEDWATER PCSR POWER CONVERSION SYSTEM RECOVERY RCI RCIC RPS REACTOR SHUTDOWN RPT RECIRC PUMP TRIP SLC STANDBY LIQUID CONTROL SPC SUPPRESSION POOL COOLING VA ALTERNATE LOW PRESS INJECTION Cut Set Report - LOMFW 30 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET 1.94E-8 100 Displaying 11 Cut Sets. (11 Original) 1 1.50E-8 77.27 IE-LOMFW,CV05,CVS-XHE-XM-VENT1,MSS-TBV-CC-BYPAS,PCS-XHE-XL-LTLOFW,RHR-XHE-XM-ERROR 2 4.28E-9 22.08 IE-LOMFW,CV03,CVS-XHE-XM-VENT1,MSS-TBV-CC-BYPAS,PCS-XHE-XL-LTLOFW,RHR-XHE-XM-ERROR A-1

LER 440-2014-005 Cut Set Report - LOMFW 23 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET 1.32E-8 100 Displaying 209 Cut Sets. (209 Original) 1 1.87E-9 14.18 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 2 9.63E-10 7.30 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 3 7.14E-10 5.41 IE-LOMFW,ADS-XHE-XM-MDEPR,DCP-BAT-TM-U1BOP1,ESW-MDP-TM-PUMPC,RCI-TDP-FR-PUMP 4 4.24E-10 3.21 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MOV-FT-SUCTR,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 5 3.68E-10 2.79 IE-LOMFW,ADS-XHE-XM-MDEPR,DCP-BAT-TM-U1BOP1,HCS-MDP-TM-HPCS,RCI-TDP-FR-PUMP 6 3.58E-10 2.71 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-FS-MDFWP,RCI-TDP-FR-PUMP 7 3.06E-10 2.32 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-TM-MDFWP,RCI-TDP-FS-PUMP 8 2.63E-10 1.99 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,PCS-XHE-XO-ERROR,RCI-TDP-FR-PUMP 9 2.50E-10 1.89 IE-LOMFW,ADS-XHE-XM-MDEPR,CDS-AOV-CC-MKUP1,ESW-MDP-TM-PUMPC,RCI-TDP-FR-PUMP 10 2.50E-10 1.89 IE-LOMFW,ADS-XHE-XM-MDEPR,CDS-AOV-CC-MKUP2,ESW-MDP-TM-PUMPC,RCI-TDP-FR-PUMP 11 2.18E-10 1.66 IE-LOMFW,ADS-XHE-XM-MDEPR,CDS-TNK-HW-CST 12 1.92E-10 1.46 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-FS-PUMPC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 13 1.84E-10 1.40 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,MFW-MDP-FS-MDFWP,RCI-TDP-FR-PUMP 14 1.62E-10 1.23 IE-LOMFW,ADS-XHE-XM-MDEPR,DCP-BAT-TM-U1BOP1,HCS-MOV-FT-SUCTR,RCI-TDP-FR-PUMP 15 1.58E-10 1.20 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,MFW-MDP-TM-MDFWP,RCI-TDP-FS-PUMP 16 1.41E-10 1.07 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPA,HCS-MOV-FT-SUCTR,MFW-MDP-TM-MDFWP 17 1.41E-10 1.07 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MDP-TM-PUMPC,MFW-MDP-TM-MDFWP,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 18 1.41E-10 1.07 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-XHE-XR-TRNC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 19 1.36E-10 1.03 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MOV-CC-INJEC,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 20 1.36E-10 1.03 IE-LOMFW,ADS-XHE-XM-MDEPR,ESW-MOV-CC-F140,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP 21 1.35E-10 1.03 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-TM-HPCS,PCS-XHE-XO-ERROR,RCI-TDP-FR-PUMP 22 1.34E-10 1.01 IE-LOMFW,ADS-XHE-XM-MDEPR,HCS-MDP-FS-HPCS,MFW-MDP-TM-MDFWP,RCI-TDP-FR-PUMP Cut Set Report - LOMFW 77-26 Only items contributing at least 1% to the total are displayed.
  1. CCDP TOTAL% CUT SET 1.19E-8 100 Displaying 10 Cut Sets. (10 Original) 1 4.07E-9 34.30 IE-LOMFW,RPS-SYS-FC-PSOVS,RRS-CRB-CC-PUMP2 2 4.07E-9 34.30 IE-LOMFW,RPS-SYS-FC-PSOVS,RRS-CRB-CC-PUMP1 3 9.09E-10 7.67 IE-LOMFW,RPS-SYS-FC-RELAY,RRS-CRB-CC-PUMP2 4 9.09E-10 7.67 IE-LOMFW,RPS-SYS-FC-RELAY,RRS-CRB-CC-PUMP1 5 5.98E-10 5.04 IE-LOMFW,RPS-SYS-FC-CRD,RRS-CRB-CC-PUMP2 6 5.98E-10 5.04 IE-LOMFW,RPS-SYS-FC-CRD,RRS-CRB-CC-PUMP1 7 2.63E-10 2.22 IE-LOMFW,RPS-SYS-FC-HCU,RRS-CRB-CC-PUMP2 8 2.63E-10 2.22 IE-LOMFW,RPS-SYS-FC-HCU,RRS-CRB-CC-PUMP1 A-2

LER 440-2014-005 Cut Set Report - LOMFW 22 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET 9.04E-9 100 Displaying 74 Cut Sets. (74 Original) 1 1.63E-9 18.05 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-XHE-XM-ERROR,RHR-STR-CF-NLOCA,SPCAI 2 1.42E-9 15.68 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,RHR-STR-CF-NLOCA,SPCAI 3 9.08E-10 10.05 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MOV-CF-F130AB,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,SPCAI 4 7.89E-10 8.73 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MOV-CF-F130AB,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,SPCAI 5 6.09E-10 6.73 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MDP-CF-START,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,SPCAI 6 5.29E-10 5.85 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MDP-CF-START,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,SPCAI 7 2.56E-10 2.84 IE-LOMFW,CTS-XHE-XM-ERROR,FWS-XHE-XM-ERROR,MFW-MDP-TM-MDFWP,RHR-STR-CF-NLOCA,SPCAI 8 2.23E-10 2.46 IE-LOMFW,CTS-XHE-XM-ERROR,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,MFW-MDP-TM-MDFWP,RHR-STR-CF-NLOCA,SPCAI 9 1.96E-10 2.16 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-EDP-TM-PUMP,FWS-XHE-XL-PMPR,RHR-STR-CF-NLOCA,SPCAI 10 1.43E-10 1.58 IE-LOMFW,CTS-XHE-XM-ERROR,ESW-MOV-CF-F130AB,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,MFW-MDP-TM-MDFWP,SPCAI 11 1.39E-10 1.53 IE-LOMFW,DCP-BAT-TM-U1BOP1,FWS-EDP-FS-PUMP,FWS-XHE-XL-PMPR,RHR-STR-CF-NLOCA,SPCAI 12 1.24E-10 1.37 IE-LOMFW,CTS-XHE-XM-ERROR,ESW-MOV-CF-F130AB,FWS-EDP-FR-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,MFW-MDP-TM-MDFWP,SPCAI 13 1.09E-10 1.20 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MOV-CF-F130AB,FWS-EDP-TM-PUMP,FWS-XHE-XL-PMPR,LCS-XHE-XL-RCOOL,SPCAI 14 9.56E-11 1.06 IE-LOMFW,CTS-XHE-XM-ERROR,ESW-MDP-CF-START,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,MFW-MDP-TM-MDFWP,SPCAI 15 9.44E-11 1.04 IE-LOMFW,DCP-BAT-TM-U1BOP1,ESW-MDP-CF-RUN,FWS-XHE-XM-ERROR,LCS-XHE-XL-RCOOL,SPCAI Cut Set Report - LOMFW 77-04 Only items contributing at least 1% to the total are displayed.
  1. CCDP TOTAL% CUT SET 7.67E-9 100 Displaying 20 Cut Sets. (20 Original) 1 3.40E-9 44.35 IE-LOMFW,RPS-SYS-FC-PSOVS,SLC-XHE-XM-ERROR 2 1.70E-9 22.17 IE-LOMFW,RPS-SYS-FC-PSOVS,SLC-XHE-XR-SLCS 3 7.60E-10 9.91 IE-LOMFW,RPS-SYS-FC-RELAY,SLC-XHE-XM-ERROR 4 5.00E-10 6.52 IE-LOMFW,RPS-SYS-FC-CRD,SLC-XHE-XM-ERROR 5 3.80E-10 4.96 IE-LOMFW,RPS-SYS-FC-RELAY,SLC-XHE-XR-SLCS 6 2.50E-10 3.26 IE-LOMFW,RPS-SYS-FC-CRD,SLC-XHE-XR-SLCS 7 2.20E-10 2.87 IE-LOMFW,RPS-SYS-FC-HCU,SLC-XHE-XM-ERROR 8 1.10E-10 1.43 IE-LOMFW,RPS-SYS-FC-HCU,SLC-XHE-XR-SLCS 9 1.09E-10 1.42 IE-LOMFW,RPS-SYS-FC-PSOVS,SLC-EPV-CF-F004AB Cut Set Report - LOMFW 77-02 Only items contributing at least 1% to the total are displayed.
  1. CCDP TOTAL% CUT SET Total 2.44E-9 100 Displaying 4 Cut Sets. (4 Original) 1 1.70E-9 69.67 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-PSOVS 2 3.80E-10 15.57 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-RELAY 3 2.50E-10 10.25 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-CRD 4 1.10E-10 4.51 IE-LOMFW,OPR-XHE-XM-NOOVRFIL,RPS-SYS-FC-HCU A-3

LER 440-2014-005 Cut Set Report - LOMFW 77-03 Only items contributing at least 1% to the total are displayed.

  1. CCDP TOTAL% CUT SET Total 2.44E-9 100 Displaying 4 Cut Sets. (4 Original) 1 1.70E-9 69.67 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-PSOVS 2 3.80E-10 15.57 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-RELAY 3 2.50E-10 10.25 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-CRD 4 1.10E-10 4.51 IE-LOMFW,OPR-XHE-XM-ADSINHIB,RPS-SYS-FC-HCU Referenced Events Event Description Probability ADS-XHE-XM-MDEPR OPERATOR FAILS TO DEPRESSURIZE THE REACTOR 5.00E-4 CDS-AOV-CC-MKUP1 MAKEUP PATH 1 FAILS 9.51E-4 CDS-AOV-CC-MKUP2 MAKEUP PATH 2 FAILS 9.51E-4 CDS-TNK-HW-CST CONDENSATE STORAGE TANK FAILS 4.37E-7 CTS-XHE-XM-ERROR OPERATOR FAILS TO ALIGN CONDENSATE TRANSFER ALTERNATE INJECTION 6.00E-2 CV03 CONTAINMENT FAILURE CAUSES LOSS OF INJECTION 4.00E-2 CV05 CONTAINMENT FAILURE CAUSES LOSS OF INJECTION 1.40E-1 CVS-XHE-XM-VENT1 OPERATOR FAILS TO VENT CONTAINMENT (DEP EVT) 5.09E-2 DCP-BAT-TM-U1BOP1 UNIT 1 BOP BATTERY D-1-B IS IN TEST OR MAINTENANCE 2.72E-3 ESW-MDP-CF-RUN ESW PUMPS FAIL FROM COMMON CAUSE TO RUN 5.78E-7 ESW-MDP-CF-START ESW PUMPS FAIL FROM COMMON CAUSE TO START 3.73E-6 ESW-MDP-FS-PUMPC ESW PUMP 1P45-C002 FAILS TO START 1.36E-3 ESW-MDP-TM-PUMPA ESW PUMP 1P45-C001A IS IN TEST OR MAINTENANCE 1.32E-2 ESW-MDP-TM-PUMPC ESW PUMP 1P45-C002 IS IN TEST OR MAINTENANCE 1.32E-2 ESW-MOV-CC-F140 ESW PUMP C DISCH MOV F140 FAILS TO OPEN 9.63E-4 ESW-MOV-CF-F130AB ESW MOVS F130A, B FAIL FROM COMMON CAUSE 5.56E-6 ESW-XHE-XR-TRNC ESW TRAIN C NOT RESTORED AFTER MAINTENANCE 1.00E-3 FWS-EDP-FR-PUMP FIREWATER PUMP FAILS TO RUN 5.21E-2 FWS-EDP-FS-PUMP FIREWATER PUMP FAILS TO START 5.09E-3 FWS-EDP-TM-PUMP DIESEL FIREWATER PUMP UNAVAILABLE BECAUSE OF MAINTENANCE 7.19E-3 FWS-XHE-XL-PMPR OFFSITE PUMPER TRUCK FAILS TO ARRIVE AND PROVIDE WATER 1.00E+0 FWS-XHE-XM-ERROR OPERATOR FAILS TO ALIGN FIREWATER INJECTION 6.00E-2 HCS-MDP-FS-HPCS HPCS PUMP FAILS TO START 9.47E-4 HCS-MDP-TM-HPCS HPCI TRAIN IS UNAVAILABLE BECAUSE OF MAINTENANCE 6.82E-3 HCS-MOV-CC-INJEC HPCS INJECTION VALVE FAILS TO OPEN 9.63E-4 HCS-MOV-FT-SUCTR HPCS SUCTION TRANSFER FAILS 3.00E-3 IE-LOMFW LOSS OF FEEDWATER 1.00E+0 LCS-XHE-XL-RCOOL OPERATOR FAILS TO RECOVER ROOM COOLING 1.00E+0 MFW-MDP-FS-MDFWP FEEDWATER PUMP 1N27-C004 FAILS TO START 1.36E-3 MFW-MDP-TM-MDFWP FEEDWATER PUMP 1N27-C004 IS IN TEST OR MAINTENANCE 7.12E-3 MSS-TBV-CC-BYPAS TURBINE BYPASS VALVES FAIL TO OPEN 4.20E-3 OPR-XHE-XM-ADSINHIB OPERATOR FAILS TO INHIBIT ADS AND CONTROL LVL 1.00E-3 OPR-XHE-XM-NOOVRFIL OPERATOR FAILS TO CONTROL LEVEL 1.00E-3 PCS-XHE-XL-LTLOFW OPERATOR FAILS TO RECOVER THE MAIN CONDENSER 1.00E+0 PCS-XHE-XO-ERROR OPERATOR FAILS TO MAINTAIN FEEDWATER INJECTION 1.00E-3 RCI-RESTART RESTART OF RCIC IS REQUIRED 1.50E-1 RCI-TDP-FR-PUMP RCIC PUMP FAILS TO RUN GIVEN THAT IT STARTED 3.97E-2 RCI-TDP-FS-PUMP RCIC PUMP FAILS TO START 6.49E-3 RCI-TDP-FS-RSTRT RCIC FAILS TO RESTART GIVEN START AND SHORT-TERM RUN 8.00E-2 RCI-XHE-XL-RSTRT OPERATOR FAILS TO RECOVER RCIC FAILURE TO RESTART 2.50E-1 RHR-STR-CF-NLOCA SUPPRESSION POOL STRAINERS FAIL FROM COMMON CAUSE (NON-LOCA) 1.00E-5 RHR-XHE-XM-ERROR OPERATOR FAILS TO START/CONTROL RHR 5.00E-4 RPS-SYS-FC-CRD CONTROL ROD DRIVE MECHANICAL FAILURE 2.50E-7 RPS-SYS-FC-HCU HCU COMPONENTS FAIL 1.10E-7 A-4

LER 440-2014-005 RPS-SYS-FC-PSOVS HCU SCRAM PILOT SOVS FAIL 1.70E-6 RPS-SYS-FC-RELAY TRIP SYSTEM RELAYS FAIL 3.80E-7 RRS-CRB-CC-PUMP1 RECIRC PUMP 1 FIELD BREAKER FAILS TO OPEN 2.39E-3 RRS-CRB-CC-PUMP2 RECIRC PUMP 2 FIELD BREAKER FAILS TO OPEN 2.39E-3 SLC-EPV-CF-F004AB SLC SQUIB VALVES FAIL FROM COMMON CAUSE 6.43E-5 SLC-XHE-XM-ERROR OPERATOR FAILS START/CONTROL SLC 2.00E-3 SLC-XHE-XR-SLCS OPERATOR FAILS TO RESTORE SLCS AFTER MAINTENANCE 1.00E-3 SPCAI SUPPRESSION POOL CLEANUP ALTERNATE INJECTION IS UNAVAILABLE 1.00E+0 A-5

LER 440-2014-005 Appendix B: Key Event Tree Figure B-1: Perry, Unit 1 LOMFW Event Tree B-1

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