ML16145A114
| ML16145A114 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/24/2016 |
| From: | Pfefferkorn C NRC/RES/DRA/PRB |
| To: | Tennessee Valley Authority |
| Candace Pfefferkorn 301-415-8395 | |
| References | |
| IR 2015002, LER 15-001-00 | |
| Download: ML16145A114 (15) | |
Text
1 ASP Screening Analysis - REJECT Accident Sequence Precursor Program - Office of Nuclear Regulatory Research Browns Ferry Nuclear Plant, Unit 3 High Pressure Coolant Injection and Reactor Core Isolation Cooling Inoperable Due to No Suction Source Aligned Event Date: 02/11/2015 LER: 296-2015-001 IR: 50-296/15-02 Plant Type: Boiling Water Reactor (BWR); General Electric Type 4 with Wet, Mark I Containment Plant Operating Mode (Reactor Power Level): Mode 1 (100% Reactor Power)
Analyst: Candace Pfefferkorn Reviewer: Keith Tetter Contributors: David Aird/Chris Hunter BC Approved Date:
05/11/16 Event Description. On February 11, 2015, at 08:20 am, the High Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems at Browns Ferry Nuclear Plant (BFN) Unit 3 were declared inoperable after operations personnel performing a HPCI system valve position verification monthly surveillance test closed supply breaker 3-BKR-2-166 to flow control isolation valve 3-FCV-2-166 causing the valve to inadvertently close and isolate the normal condensate storage tank (CST) suction source for HPCI and RCIC. At 08:24 am operations personnel opened valve 3-FCV-2-166 remotely using a hand switch in the BFN Unit 1 control room restoring the normal CST suction source. With valve 3-FCV-2-166 open, an operator in the field manually opened breaker 3-BKR-2-166 to prevent the possibility of further valve movement.
The direct cause of the inadvertent valve closure was found to be faulty stuck contacts on a control room hand switch. The apparent cause of the event was found to be an inadequate design change review that introduced a latent design vulnerability to the plant. Specifically, the design change altered the configuration of breaker 3-BKR-2-166 from normally closed to normally open to address fire concerns. The design change review assumed that the breaker would remain open at all times eliminating the requirement for additional protective measures against spurious valve closure.
However, a requirement for operations personnel to close breaker 3-BKR-2-166 in order to verify valve 3-FCV-2-166 position was nonetheless included in an update to surveillance procedure 3-SR-3.5.1.2 (HPIC), titled High Pressure Coolant Injection System Monthly Valve Position Verification when the design change was implemented in 2010.
SDP Result. In Inspection Report 50-296/15-02 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15223A508), the inspectors documented their review of License Event Report (LER) 296-2015-001 (ADAMS Accession No. ML15114A289). The inspectors determined that the LER adequately documented the summary of the event including the cause of the event and the potential safety consequences. The inspectors noted that the licensee made design changes to prevent spurious operation of the CST discharge values when pertinent breakers are closed for testing. No findings were identified and the inspectors closed the LER.
Analysis Type. The BFN Unit 3 Standardized Plant Analysis Risk (SPAR) model, Revision 8.18, created May 20, 2014, was used for this event analysis. The event was modeled as a condition assessment.
LER 296-2015-001 2
Analysis Rules. The ASP program uses Significance Determination Process (SDP) results for degraded conditions when available. However, the ASP Program performs independent analyses for events involving reactor trips. In addition, any system, structure, or component that was determined to be degraded, failed, or unavailable due to test/maintenance during the event is factored into the ASP analysis (regardless of whether the failures or degradations are due to licensee performance deficiency).
Key Modeling Assumptions. The following modeling assumptions were determined to be vital to this event analysis:
In this event, the loss of CST suction to HPIC and RCIC lasted for only four minutes; however, the smallest time unit option in the Events and Conditions Assessment (ECA) workspace within the Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) is one hour. Therefore, the event duration for this analysis was set to one hour and thus values generated for the change in core damage probability (CDP) reflect a conservative estimate of the actual CDP.
Default SAPHIRE ECA solution settings were used (e.g. cut set truncation, 1.00x10-11; size truncation, none; solve method, multiple pass; etc.)
SPAR Model Modifications. Fault tree modifications and basic event additions were made within the BFN Unit 3 SPAR model as described below:
A new house event, titled CST-FCV-166 (Isolation Flow Control Valve 3-FCV-2-166 Fails Closed) was created to model the operational state of valve 3-FCV-2-166. The normal state of this valve is open and therefore CST-FCV-166 was set to FALSE.
In the HCI (HPCI) fault tree, the HCI02 (CST-LOCHS FLAG) OR logic gate and its associated basic house event, titled HE-LOCHS (House Event - Total Loss of Condenser Heat Sink Initiator) were deleted because the CST remains available during a loss of condenser heat sink event.
The HCI fault tree was modified to include the basic house event CST-FCV-166 under a newly added OR gate, titled HCI03 (CST Suction Fails). The basic event CDS-TNK-HW-CST (Condensate Storage Tank Fails), originally located under the HCI02 OR logic gate, is now located under HCI03. HCI was modified as described since failure of the CST or closure of valve 3-FCV-2-166 would result in a loss of CST suction to HPCI.
The RCI (RCIC) fault tree was modified to include the basic house event CST-FCV-166 under a newly added OR gate, titled RCI12 (CST Suction Fails). The basic event CDS-TNK-HW-CST is now located under RCI12. RCI was modified as described since failure of the CST or closure of valve 3-FCV-2-166 would result in a loss of CST suction to RCIC.
The HPCI fault tree related to specific station black out (SBO) scenarios, titled HCI01 (Browns Ferry 3 HPCI System Fault Tree) was modified to include the basic house event CST-FCV-166 under a newly added OR gate, HCI0122 (CST Suction Fails). The basic event CDS-TNK-HW-CST is now located under HCI0122. HCI01 was modified as described since failure of the CST or closure of valve 3-FCV-2-166 would result in a loss of CST suction to HPCI.
LER 296-2015-001 3
The RCIC fault tree related to specific SBO scenarios, titled RCI01 (RCIC), was modified to include the basic house event CST-FCV-166 under a newly added OR gate, RCI0132 (CST Suction Fails). The basic event CDS-TNK-HW-CST is now located under RCI0132. RCI01 was modified as described since failure of the CST or closure of valve 3-FCV-2-166 would result in a loss of CST suction to RCIC.
The OR gate associated with RCI01-1 (RCIC Water Supplies Are Unavailable) in the RCI01 fault tree was changed to an AND gate to reflect RCIC water supply availability given either CST or Torus suction.
Basic Event Probability Changes. At the time of the event BFN Unit 3 was at full power and no components were reported as being out of service for test and maintenance. However, valve 3-FCV-2-166 was closed in the February 11, 2015, event, and thus the basic event titled CST-FCV-166 was set to TRUE for this event analysis.
Rejection Basis. The CDP for this analysis is 8.7x10-12 which is below the ASP Program CDP threshold of 1x10-6. Therefore, this event is not a precursor and is screened out of the ASP Program.
A-1 Appendix A: SAPHIRE 8 Worksheet Summary of Conditional Event Changes Event Description Cond Value Nominal Value CST-FCV-166 Isolation Flow Control Valve 3-FCV-2-166 Fails Closed True False Event Tree Dominant Results Only items contributing at least 1.0% to the total CCDP are displayed.
EV E N T T RE E CCDP CDP CDP D E S C R I P T I ON LOCHS 6.88E-11 6.48E-11 3.96E-12 BROWNS FERRY 3 - LOSS OF CONDENSER HEAT SINK IORV 6.19E-11 5.92E-11 2.75E-12 BROWNS FERRY 3 - INADVERTENT OPEN RELIEF VALVE MLOCA 2.04E-11 1.98E-11 6.34E-13 BROWNS FERRY 3 - MEDIUM LOSS-OF-COOLANT ACCIDENT LOOPGR 6.29E-11 6.23E-11 5.24E-13 BROWNS FERRY 3 - LOSS OF OFFSITE POWER - GRID RELATED LOOPSC 4.36E-11 4.33E-11 3.61E-13 BROWNS FERRY 3 - LOSS OF OFFSITE POWER - SWITCHYARD CENTERED LOPCA 8.53E-12 8.33E-12 2.04E-13 BROWNS FERRY 3 - LOSS OF PLANT CONTROL AIR LOOPWR 4.51E-11 4.50E-11 1.42E-13 BROWNS FERRY 3 - LOSS OF OFFSITE POWER - WEATHER RELATED SLBOC 1.81E-11 1.80E-11 9.47E-14 BROWNS FERRY 3 - STEAM LINE BREAK OUTSIDE CONTAINMENT Total 3.68E-10 3.59E-10 8.72E-12 Dominant Sequence Results Only items contributing at least 1.0% to the total CCDP are displayed.
EV E N T T R E E SE QU E N C E CCDP CDP CDP D E S C R I P T I ON LOCHS 59 5.58E-11 5.18E-11 3.96E-12
/RPS, /SRV, HPI, DEP, CR2 IORV 46 6.06E-11 5.78E-11 2.75E-12
/RPS, PCS, HPI, DEP MLOCA 51 1.38E-11 1.32E-11 6.16E-13
/RPS, /VSS, HCI, DEP LOOPGR 25 4.86E-12 4.54E-12 3.24E-13
/RPS, /EPS, /SRV, HPI, DEP LOOPSC 25 4.14E-12 3.87E-12 2.74E-13
/RPS, /EPS, /SRV, HPI, DEP LOPCA 54 2.98E-12 2.78E-12 1.95E-13
/RPS, /SRV, HPI, DEP, CR2 LOOPGR 24 2.02E-12 1.86E-12 1.61E-13
/RPS, /EPS, /SRV, HPI, /DEP, LPI, VA LOOPWR 25 1.55E-12 1.45E-12 9.93E-14
/RPS, /EPS, /SRV, HPI, DEP SLBOC 59 1.47E-12 1.38E-12 9.47E-14
/RPS, /MSIV, HPI, DEP, CR2 Total 3.68E-10 3.59E-10 8.72E-12
LER 296-2015-001 A-2 Referenced Fault Trees Fault Tree Description CR2 BROWNS FERRY 3 CRD SYSTEM FAULT TREE DEP MANUAL REACTOR DEPRESS HCI HPCI HPI HIGH PRESSURE INJECTION (RCIC or HPCI)
LPI LOW PRESSURE INJECTION (CS or LPCI)
PCS POWER CONVERSION SYSTEM VA ALTERNATE LOW PRESS INJECTION Cut Set Report - LOCHS 59 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 4.89E-7 100 Displaying 146 Cut Sets. (146 Original) 1 1.09E-7 22.38 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FR-TRAIN 2
5.24E-8 10.72 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-XHE-XE-MISCAL 3
4.96E-8 10.16 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FR-TRAIN 4
3.12E-8 6.39 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FR-TRAIN 5
3.02E-8 6.18 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-TM-TRAIN 6
2.38E-8 4.87 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-XHE-XE-MISCAL 7
1.79E-8 3.66 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-FR-TRAIN 8
1.79E-8 3.66 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FS-TRAIN 9
1.50E-8 3.06 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-XHE-XE-MISCAL 10 1.37E-8 2.80 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-TM-TRAIN 11 8.57E-9 1.75 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-XHE-XE-MISCAL 12 8.27E-9 1.69 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 13 8.12E-9 1.66 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FS-TRAIN 14 5.49E-9 1.12 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-MOV-FC-XFER,RCI-XHE-XL-XFER 15 5.11E-9 1.05 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FS-TRAIN 16 4.94E-9 1.01 IE-LOCHS,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-TM-TRAIN
LER 296-2015-001 A-3 Cut Set Report - IORV 46 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 5.31E-7 100 Displaying 18 Cut Sets. (18 Original) 1 3.23E-7 60.92 IE-IORV,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN 2
9.23E-8 17.40 IE-IORV,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN 3
5.29E-8 9.97 IE-IORV,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN 4
1.39E-8 2.61 IE-IORV,ADS-XHE-XM-MDEPR,HCI-XHE-XE-MISCAL 5
8.15E-9 1.54 IE-IORV,ADS-XHE-XM-MDEPR,HCI-XHE-XO-ERROR 6
7.85E-9 1.48 IE-IORV,ADS-XHE-XM-MDEPR,HCI-MOV-CC-F027 7
7.85E-9 1.48 IE-IORV,ADS-XHE-XM-MDEPR,HCI-MOV-OO-F040 8
7.85E-9 1.48 IE-IORV,ADS-XHE-XM-MDEPR,HCI-MOV-CC-F026 9
7.85E-9 1.48 IE-IORV,ADS-XHE-XM-MDEPR,HCI-MOV-CC-F016 10 7.85E-9 1.48 IE-IORV,ADS-XHE-XM-MDEPR,HCI-MOV-CC-F044 Cut Set Report - MLOCA 51 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 1.21E-7 100 Displaying 10 Cut Sets. (10 Original) 1 7.38E-8 61.04 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-TDP-FR-TRAIN 2
2.11E-8 17.44 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-TDP-TM-TRAIN 3
1.21E-8 9.99 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-TDP-FS-TRAIN 4
3.16E-9 2.62 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-XHE-XE-MISCAL 5
1.86E-9 1.54 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-XHE-XO-ERROR 6
1.79E-9 1.48 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-MOV-CC-F027 7
1.79E-9 1.48 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-MOV-OO-F040 8
1.79E-9 1.48 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-MOV-CC-F026 9
1.79E-9 1.48 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-MOV-CC-F016 10 1.79E-9 1.48 IE-MLOCA,ADS-XHE-XM-MLOCA,HCI-MOV-CC-F044
LER 296-2015-001 A-4 Cut Set Report - LOOPGR 25 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 4.26E-8 100 Displaying 88 Cut Sets. (88 Original) 1 9.59E-9 22.52 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FR-TRAIN 2
4.60E-9 10.79 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-XHE-XE-MISCAL 3
4.35E-9 10.22 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FR-TRAIN 4
2.74E-9 6.43 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FR-TRAIN 5
2.65E-9 6.22 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-TM-TRAIN 6
2.09E-9 4.90 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-XHE-XE-MISCAL 7
1.57E-9 3.69 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FS-TRAIN 8
1.57E-9 3.69 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-FR-TRAIN 9
1.31E-9 3.08 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-XHE-XE-MISCAL 10 1.20E-9 2.82 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-TM-TRAIN 11 7.53E-10 1.77 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-XHE-XE-MISCAL 12 7.26E-10 1.70 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 13 7.13E-10 1.67 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FS-TRAIN 14 4.82E-10 1.13 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-MOV-FC-XFER,RCI-XHE-XL-XFER 15 4.49E-10 1.05 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FS-TRAIN 16 4.34E-10 1.02 IE-LOOPGR,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-TM-TRAIN
LER 296-2015-001 A-5 Cut Set Report - LOOPSC 25 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 3.63E-8 100 Displaying 83 Cut Sets. (83 Original) 1 8.18E-9 22.55 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FR-TRAIN 2
3.92E-9 10.80 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-XHE-XE-MISCAL 3
3.71E-9 10.24 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FR-TRAIN 4
2.34E-9 6.44 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FR-TRAIN 5
2.26E-9 6.23 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-TM-TRAIN 6
1.78E-9 4.90 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-XHE-XE-MISCAL 7
1.34E-9 3.69 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-FR-TRAIN 8
1.34E-9 3.69 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FS-TRAIN 9
1.12E-9 3.09 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-XHE-XE-MISCAL 10 1.02E-9 2.83 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-TM-TRAIN 11 6.42E-10 1.77 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-XHE-XE-MISCAL 12 6.19E-10 1.71 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 13 6.08E-10 1.68 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FS-TRAIN 14 4.11E-10 1.13 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-MOV-FC-XFER,RCI-XHE-XL-XFER 15 3.83E-10 1.05 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FS-TRAIN 16 3.70E-10 1.02 IE-LOOPSC,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-TM-TRAIN
LER 296-2015-001 A-6 Cut Set Report - LOPCA 54 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 2.61E-8 100 Displaying 80 Cut Sets. (80 Original) 1 5.89E-9 22.57 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FR-TRAIN 2
2.82E-9 10.81 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-XHE-XE-MISCAL 3
2.67E-9 10.24 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FR-TRAIN 4
1.68E-9 6.45 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FR-TRAIN 5
1.63E-9 6.23 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-TM-TRAIN 6
1.28E-9 4.91 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-XHE-XE-MISCAL 7
9.64E-10 3.70 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-FR-TRAIN 8
9.64E-10 3.70 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FS-TRAIN 9
8.06E-10 3.09 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-XHE-XE-MISCAL 10 7.38E-10 2.83 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-TM-TRAIN 11 4.62E-10 1.77 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-XHE-XE-MISCAL 12 4.46E-10 1.71 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 13 4.38E-10 1.68 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FS-TRAIN 14 2.96E-10 1.13 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-MOV-FC-XFER,RCI-XHE-XL-XFER 15 2.76E-10 1.06 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FS-TRAIN 16 2.66E-10 1.02 IE-LOPCA,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-TM-TRAIN
LER 296-2015-001 A-7 Cut Set Report - LOOPGR 24 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 1.77E-8 100 Displaying 216 Cut Sets. (216 Original) 1 1.91E-9 10.78 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 2
9.64E-10 5.43 IE-LOOPGR,EPS-DGN-TM-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 3
9.16E-10 5.16 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-XHE-XE-MISCAL 4
8.68E-10 4.89 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 5
5.46E-10 3.08 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-TM-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 6
5.30E-10 2.99 IE-LOOPGR,DCP-XHE-XM-BB3,EPS-DGN-FR-DGC,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 7
5.28E-10 2.98 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-TM-TRAIN 8
4.62E-10 2.60 IE-LOOPGR,EPS-DGN-TM-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-XHE-XE-MISCAL 9
4.37E-10 2.47 IE-LOOPGR,EPS-DGN-TM-DGC,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 10 4.16E-10 2.34 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,OPR-XHE-XR-CASLT,RCI-XHE-XE-MISCAL 11 3.13E-10 1.76 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-FS-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 12 3.13E-10 1.76 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FS-TRAIN 13 2.75E-10 1.55 IE-LOOPGR,EPS-DGN-TM-DGC,HCI-TDP-TM-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 14 2.67E-10 1.51 IE-LOOPGR,DCP-XHE-XM-BB3,EPS-DGN-TM-DGC,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN 15 2.66E-10 1.50 IE-LOOPGR,EPS-DGN-TM-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-TM-TRAIN 16 2.62E-10 1.48 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-TDP-TM-TRAIN,OPR-XHE-XR-CASLT,RCI-XHE-XE-MISCAL 17 2.54E-10 1.43 IE-LOOPGR,DCP-XHE-XM-BB3,EPS-DGN-FR-DGC,OPR-XHE-XR-CASLT,RCI-XHE-XE-MISCAL 18 2.40E-10 1.35 IE-LOOPGR,EPS-DGN-FR-DGC,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,OPR-XHE-XR-CASLT,RCI-TDP-TM-TRAIN 19 2.10E-10 1.18 IE-LOOPGR,EPS-DGN-TM-DGC,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,OPR-XHE-XR-CASLT,RCI-XHE-XE-MISCAL 20 1.94E-10 1.09 IE-LOOPGR,EPS-DGN-FS-DGC,HCI-TDP-FR-TRAIN,OPR-XHE-XR-CASLT,RCI-TDP-FR-TRAIN
LER 296-2015-001 A-8 Cut Set Report - LOOPWR 25 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 1.36E-8 100 Displaying 72 Cut Sets. (72 Original) 1 3.08E-9 22.66 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FR-TRAIN 2
1.47E-9 10.85 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-XHE-XE-MISCAL 3
1.40E-9 10.28 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FR-TRAIN 4
8.78E-10 6.47 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FR-TRAIN 5
8.49E-10 6.26 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-TM-TRAIN 6
6.69E-10 4.93 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-XHE-XE-MISCAL 7
5.03E-10 3.71 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-FR-TRAIN 8
5.03E-10 3.71 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FS-TRAIN 9
4.21E-10 3.10 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-XHE-XE-MISCAL 10 3.85E-10 2.84 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-TM-TRAIN 11 2.41E-10 1.78 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-XHE-XE-MISCAL 12 2.33E-10 1.71 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 13 2.28E-10 1.68 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FS-TRAIN 14 1.54E-10 1.14 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-MOV-FC-XFER,RCI-XHE-XL-XFER 15 1.44E-10 1.06 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FS-TRAIN 16 1.39E-10 1.02 IE-LOOPWR,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-TM-TRAIN
LER 296-2015-001 A-9 Cut Set Report - SLBOC 59 Only items contributing at least 1% to the total are displayed.
PROB/F RE Q T OT AL%
C UT SE T 1.29E-8 100 Displaying 72 Cut Sets. (72 Original) 1 2.93E-9 22.66 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FR-TRAIN 2
1.40E-9 10.85 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-XHE-XE-MISCAL 3
1.33E-9 10.28 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FR-TRAIN 4
8.36E-10 6.47 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FR-TRAIN 5
8.08E-10 6.26 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-TM-TRAIN 6
6.36E-10 4.93 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-XHE-XE-MISCAL 7
4.79E-10 3.71 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-FR-TRAIN 8
4.79E-10 3.71 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-TDP-FS-TRAIN 9
4.00E-10 3.10 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-XHE-XE-MISCAL 10 3.67E-10 2.84 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-TM-TRAIN 11 2.29E-10 1.78 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-XHE-XE-MISCAL 12 2.21E-10 1.71 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-RESTART,RCI-TDP-FS-RSTRT,RCI-XHE-XL-RSTRT 13 2.17E-10 1.68 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-MOV-CC-IVFRO,HCI-MULTIPLE-INJECT,HCI-XHE-XL-INJECT,RCI-TDP-FS-TRAIN 14 1.47E-10 1.14 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FR-TRAIN,RCI-MOV-FC-XFER,RCI-XHE-XL-XFER 15 1.37E-10 1.06 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-TM-TRAIN,RCI-TDP-FS-TRAIN 16 1.32E-10 1.02 IE-SLBOC,ADS-XHE-XM-MDEPR,HCI-TDP-FS-TRAIN,RCI-TDP-TM-TRAIN
LER 296-2015-001 A-10 Referenced Events Event Description Probability ADS-XHE-XM-MDEPR OPERATOR FAILS TO DEPRESSURIZE THE REACTOR 5.00E-4 ADS-XHE-XM-MLOCA OPERATOR FAILS TO DEPRESSURIZE THE REACTOR -
MLOCA (PSA) 1.86E-2 DCP-XHE-XM-BB3 OPERATOR FAILS TO ALIGN BACKUP POWER TO DC-BATBD3 1.10E-2 EPS-DGN-FR-DGC DIESEL GENERATOR C FAILS TO RUN 2.85E-2 EPS-DGN-FS-DGC DIESEL GENERATOR C FAILS TO START 2.89E-3 EPS-DGN-TM-DGC DG C IS UNAVAILABLE BECAUSE OF MAINTENANCE 1.43E-2 HCI-MOV-CC-F016 STEAM SUPPLY VALVE 73-16 FAILS TO OPEN 9.63E-4 HCI-MOV-CC-F026 TORUS SUCTION VALVE 73-26 FAILS TO OPEN 9.63E-4 HCI-MOV-CC-F027 TORUS SUCTION VALVE 73-27 FAILS TO OPEN 9.63E-4 HCI-MOV-CC-F044 HPCI INJECTION VALVE F044 CAUSES FAILURE TO START 9.63E-4 HCI-MOV-CC-IVFRO HPCI INJECTION VALVE FAILS TO REOPEN 1.50E-1 HCI-MOV-OO-F040 CST ISOLATION VALVE 73-40 FAILS TO CLOSE 9.63E-4 HCI-MULTIPLE-INJECT MULTIPLE HPCI INJECTIONS REQUIRED 1.50E-1 HCI-TDP-FR-TRAIN HPCI PUMP TRAIN FAILS TO RUN GIVEN IT STARTED 3.97E-2 HCI-TDP-FS-TRAIN HPCI PUMP FAILS TO START 6.49E-3 HCI-TDP-TM-TRAIN HPCI TRAIN IS UNAVAILABLE BECAUSE OF MAINTENANCE 1.13E-2 HCI-XHE-XE-MISCAL MISCALIBRATION OF HPCI EXHAUST PRESSURE INSTRUMENTATION 1.70E-3 HCI-XHE-XL-INJECT OPERATOR FAILS TO RECOVER HPCI INJECT MOV FAILURE TO REOPEN 8.00E-1 HCI-XHE-XO-ERROR OPERATOR FAILS TO START/CONTROL HCI INJECTION 1.00E-3 IE-IORV INADVERTENT OPEN RELIEF VALVE 1.63E-2 IE-LOCHS LOSS OF CONDENSER HEAT SINK 1.39E-1 IE-LOOPGR LOSS OF OFFSITE POWER INITIATOR (GRID-RELATED) 1.22E-2 IE-LOOPSC LOSS OF OFFSITE POWER INITIATOR (SWITCHYARD-CENTERED) 1.04E-2 IE-LOOPWR LOSS OF OFFSITE POWER INITIATOR (WEATHER-RELATED) 3.91E-3 IE-LOPCA LOSS OF PLANT CONTROL AIR 7.49E-3 IE-MLOCA MEDIUM LOCA 1.00E-4 IE-SLBOC STEAM LINE BREAK OUTSIDE CONTAINMENT 3.72E-3 OPR-XHE-XR-CASLT MISALIGNMENT AFTER COMMON ACCIDENT SIGNAL LOGIC TEST (PSA) 3.50E-3 RCI-MOV-FC-XFER RCIC FAILS TO TRANSFER DURING RECIRCULATION 7.97E-3 RCI-RESTART RESTART OF RCIC IS REQUIRED 1.50E-1 RCI-TDP-FR-TRAIN RCIC PUMP FAILS TO RUN GIVEN THAT IT STARTED 3.97E-2 RCI-TDP-FS-RSTRT RCIC FAILS TO RESTART GIVEN START AND SHORT-TERM RUN 8.00E-2 RCI-TDP-FS-TRAIN RCIC PUMP FAILS TO START 6.49E-3 RCI-TDP-TM-TRAIN RCIC PUMP TRAIN IS UNAVAILABLE BECAUSE OF MAINTENANCE 1.09E-2 RCI-XHE-XE-MISCAL RCIC FAILS FROM MISCALIBRATION OF RUPTURE DISC 1.90E-2 RCI-XHE-XL-RSTRT OPERATOR FAILS TO RECOVER RCIC FAILURE TO RESTART 2.50E-1 RCI-XHE-XL-XFER OPERATOR FAILS TO RECOVER SUCTN XFER FAILURE 2.50E-1
B-1 Appendix B: Key Fault Trees HCI Fault Tree HCI01 Fault Tree
LER 296-2015-001 B-2 RCI Fault Tree RCI01 Fault Tree