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APR1400-K-X-ER-14001-NP, Rev. 2, Applicant'S Environmental Report - Standard Design Certification.
	ML18225A335
Person / Time
Site:	05200046
Issue date:	08/13/2018
From:	; Korea Electric Power Corp, Korea Hydro & Nuclear Power Co, Ltd
To:	; Office of New Reactors
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ML18225A333	List: ML18225A334; ML18225A335;
References
	APR1400-K-X-ER-14001-NP, Rev 2
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APR1400 APPLICANTS ENVIRONMENTAL REPORT

- STANDARD DESIGN CERTIFICATION APR1400-K-X-ER-14001-NP REVISION 2 August 2018

© 2018 KOREA ELECTRIC POWER CORPORATION KOREA HYDRO & NUCLEAR POWER CO., LTD All Rights Reserved This document was prepared for the design certification application to the U.S. Nuclear Regulatory Commission and contains technological information that constitutes intellectual property of Korea Hydro & Nuclear Power Co., Ltd.

Copying, using, or distributing the information in this document in whole or in part is permitted only to the U.S. Nuclear Regulatory Commission and its contractors for the purpose of reviewing design certification application materials. Other uses are strictly prohibited without the written permission of Korea Electric Power Corporation and Korea Hydro & Nuclear Power Co., Ltd.

APR1400 Applicants Environmental Report - Standard Design Certification TABLE OF CONTENTS NUMBER TITLE PAGE ACRONYMS AND ABBREVIATIONS ...................................................................... XIII

1. INTRODUCTION ...................................................................................................... 1-1

2. METHODOLOGY ..................................................................................................... 2-1

3. BASE RISK ................................................................................................................. 3-1

4. UNMITIGATED RISK MONETARY VALUE ...................................................... 4-1 4.1 Averted Public Exposure (APE) ......................................................................... 4-2 4.1.1 APE for At-Power Internal Events ....................................................... 4-2 4.1.2 APE for At-Power Internal Flooding Events ........................................ 4-3 4.1.3 APE for At-Power Internal Fire Events ................................................ 4-3 4.1.4 APE for LPSD Internal Events ............................................................. 4-3 4.1.5 APE for LPSD Flooding Events ........................................................... 4-3 4.1.6 APE for LPSD Fire Events ................................................................... 4-3 4.1.7 Total APE ............................................................................................. 4-3 4.2 Averted Offsite Property Damage Costs (AOC)................................................. 4-4 4.2.1 AOC for At-Power Internal Events....................................................... 4-4 4.2.2 AOC for At-Power Internal Flooding Events ....................................... 4-4 4.2.3 AOC for At-Power Internal Fire Events ............................................... 4-5 4.2.4 AOC for LPSD Internal Events ............................................................ 4-5 4.2.5 AOC for LPSD Flooding Events .......................................................... 4-5 4.2.6 AOC for LPSD Fire Events .................................................................. 4-5 4.2.7 Total AOC............................................................................................. 4-5 4.3 Averted Occupational Exposure (AOE) ............................................................. 4-5 4.3.1 Averted Immediate Occupational Exposure Costs ............................... 4-6 4.3.2 Averted Long-Term Occupational Exposure Costs .............................. 4-8 4.3.3 Total Averted Occupational Exposure Costs ...................................... 4-10 4.4 Averted Onsite Costs (AOSC) .......................................................................... 4-11 4.4.1 Averted Cleanup and Decontamination Costs .................................... 4-11 i Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.4.2 Averted Replacement Power Costs..................................................... 4-13 4.4.3 Averted Repair and Refurbishment Costs........................................... 4-16 4.4.4 Total Averted Onsite Costs (AOSC) .................................................. 4-16 4.5 Cost of Enhancement (COE)............................................................................. 4-17 4.6 Total Unmitigated Baseline Risk ...................................................................... 4-17

5. IDENTIFICATION OF SAMDAS ........................................................................... 5-1

6. SAMDA SCREENING ............................................................................................... 6-1

7. SAMDA BENEFIT EVALUATION ......................................................................... 7-1 7.1 Emergency Diesel Generator Events .................................................................. 7-1 7.1.1 EDG DG001A Events ........................................................................... 7-2 7.1.2 EDG DG001B Events ........................................................................... 7-2 7.1.3 EDG DG001C Events ........................................................................... 7-3 7.1.4 EDG DG001D Events ........................................................................... 7-4 7.1.5 Load Sequencer Events ......................................................................... 7-5 7.1.6 Total EDG Event Summary .................................................................. 7-6 7.2 AAC Combustion Turbine Generator Events ..................................................... 7-6 7.2.1 AAC CTG Events ................................................................................. 7-6 7.3 Auxiliary Feedwater Events ................................................................................ 7-7 7.3.1 AFW Isolation Valve MOV-45 Events ................................................ 7-7 7.3.2 AFW Isolation Valve MOV-46 Events ................................................ 7-8 7.3.3 AFW Turbine Driven Pump PP01A Events ......................................... 7-9 7.3.4 AFW Turbine Driven Pump PP01B Events ......................................... 7-9 7.3.5 AFW Motor Driven Pump PP02A Events .......................................... 7-10 7.3.6 AFW Motor Driven Pump PP02B Events .......................................... 7-11 7.3.7 Startup FW Pump PP07 Events .......................................................... 7-11 7.3.8 Total AFW Isolation Valve Event Summary...................................... 7-12 7.3.9 Total AFW Turbine Driven Pump Event Summary ........................... 7-12 7.3.10 Total AFW Motor Driven Pump Event Summary .............................. 7-13 7.4 Fire Barrier Failure Events ................................................................................ 7-13 7.4.1 Fire Barrier Unavailability .................................................................. 7-13 ii Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.5 Component Cooling Water (CCW) Events ....................................................... 7-14 7.5.1 CCW Pump PP02A Events ................................................................. 7-14 7.5.2 CCW Pump PP02B Events ................................................................. 7-15 7.5.3 CS Heat Exchanger HE01A CCW Inlet Valve MOV-97 ................... 7-16 7.5.4 CS Heat Exchanger HE01B CCW Inlet Valve MOV-98 ................... 7-16 7.5.5 DG001A CCW Inlet Valve MOV-191 ............................................... 7-17 7.5.6 Total CCW Pump Event Summary..................................................... 7-17 7.5.7 Total CS Heat Exchanger CCW Inlet Valve Event Summary............ 7-18 7.6 Containment Spray (CS) Events ....................................................................... 7-18 7.6.1 Containment Spray Pump PP01A Events ........................................... 7-18 7.6.2 Containment Spray Pump PP01B Events ........................................... 7-19 7.6.3 Containment Spray Isolation Valve MOV-003 Events ...................... 7-20 7.6.4 Containment Spray Isolation Valve MOV-004 Events ...................... 7-20 7.6.5 Containment Spray Heat Exchanger HE-01B Events......................... 7-21 7.6.6 Containment Spray Heat Exchanger HE-01A Events ........................ 7-21 7.6.7 Total Containment Spray Pump Event Summary ............................... 7-22 7.6.8 Total Containment Spray Isolation Valve Event Summary................ 7-22 7.6.9 Total Containment Spray Heat Exchanger Event Summary............... 7-23 7.7 125 VDC Power Events .................................................................................... 7-23 7.7.1 125 VDC Power Battery BT01A Events ............................................ 7-23 7.7.2 125 VDC Power Battery BT01B Events ............................................ 7-24 7.7.3 125 VDC Power Battery BT01C Events ............................................ 7-25 7.7.4 125 VDC Power Battery BT01D Events ............................................ 7-25 7.7.5 Total 125 VDC Power Battery Event Summary ................................. 7-26 7.8 120 VAC Power Events .................................................................................... 7-26 7.8.1 120V Inverter IN01A .......................................................................... 7-26 7.8.2 120V Inverter IN01B .......................................................................... 7-27 7.8.3 120V Inverter IN01C .......................................................................... 7-28 7.8.4 120V Inverter IN01D .......................................................................... 7-28 7.8.5 Total 120V inverter Event Summary .................................................. 7-29 iii Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.9 AC Power Events .............................................................................................. 7-29 7.9.1 SAT Transformer 2M Events ............................................................. 7-29 7.9.2 SAT Transformer 2N Events .............................................................. 7-30 7.9.3 PCB SW01A-A2 To 4.16KV Switchgear SW01A Events ................. 7-31 7.9.4 PCB SW01B-A2 To 4.16KV Switchgear SW01B Events ................. 7-31 7.9.5 PCB SW01C-A2 To 4.16KV Switchgear SW01C Events ................. 7-32 7.9.6 PCB SW01A-H2 To 4.16KV Switchgear SW01A From UAT Events ............................................................................... 7-33 7.9.7 PCB SW01B-H2 To 4.16KV Switchgear SW01B From UAT Events ............................................................................... 7-33 7.9.8 PCB SW01C-C2 To 4.16KV Switchgear SW01C From UAT Events ............................................................................... 7-34 7.9.9 PCB SW01D-G2 To 4.16KV Switchgear SW01D From UAT Events ............................................................................... 7-35 7.9.10 SAT Transformer Event Summary ..................................................... 7-36 7.9.11 4.16KV Circuit Breaker Event Summary ........................................... 7-36 7.10 POSRV Events .................................................................................................. 7-37 7.10.1 POSRV V200 Events .......................................................................... 7-37 7.10.2 POSRV V201 Events .......................................................................... 7-37 7.10.3 POSRV V202 Events .......................................................................... 7-38 7.10.4 POSRV V203 Events .......................................................................... 7-39 7.10.5 Total POSRV Event Summary ........................................................... 7-39 7.11 Chiller/Cooler Events ........................................................................................ 7-40 7.11.1 ECW Chiller CH01A Events .............................................................. 7-40 7.11.2 ECW Chiller CH01B Events .............................................................. 7-41 7.11.3 ECW Chiller CH02A Events .............................................................. 7-41 7.11.4 ECW Chiller CH02B Events .............................................................. 7-42 7.11.5 EDG Room Cubical Cooler HV12A Events....................................... 7-43 7.11.6 EDG Room Cubical Cooler HV12B Events ....................................... 7-44 7.11.7 EDG Room Cubical Cooler HV12D Events....................................... 7-44 iv Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.11.8 EDG Room Cubical Cooler HV13A Events....................................... 7-45 7.11.9 EDG Room Cubical Cooler HV13B Events ....................................... 7-46 7.11.10 EDG Room Cubical Cooler HV13D Events....................................... 7-46 7.11.11 Motor Driven AFW Pump Room A Cubical Cooler HV33A Events . 7-47 7.11.12 Motor Driven AFW Pump Room B Cubical Cooler HV33B Events . 7-48 7.11.13 ECW Chiller B Cubical Cooler HV32B Events ................................. 7-49 7.11.14 Air Handling Unit AH02A Events...................................................... 7-49 7.11.15 Air Handling Unit AH02B Events ...................................................... 7-50 7.11.16 Total ECW Chiller Event Summary ................................................... 7-50 7.11.17 Total EDG Room Cubical Cooler Event Summary ............................ 7-51 7.11.18 Total Motor Driven AFW Pump Room Cubical Cooler Event Summary ......................................................... 7-51 7.11.19 Total Air Handling Unit Event Summary ........................................... 7-52 7.12 Safety Injection (SI) Events .............................................................................. 7-52 7.12.1 SI Pump PP02A Events ...................................................................... 7-52 7.12.2 SI Pump PP02B Events....................................................................... 7-53 7.12.3 SI Pump PP02C Events....................................................................... 7-54 7.12.4 SI Pump PP02D Events ...................................................................... 7-54 7.12.5 Total SI Pump Event Summary .......................................................... 7-55 7.12.6 IRWST Strainer Events ...................................................................... 7-55 7.12.7 SI Valve V-959 Events ....................................................................... 7-56 7.13 ESW Events ...................................................................................................... 7-57 7.13.1 ESW Pump PP02A Events ................................................................. 7-57 7.13.2 ESW Pump PP02B Events .................................................................. 7-57 7.13.3 ESW Filter Plugging Events ............................................................... 7-58 7.13.4 ESW CT01A Events ........................................................................... 7-59 7.13.5 ESW CT01B Events ........................................................................... 7-60 7.13.6 ESW CT02A Events ........................................................................... 7-60 7.13.7 ESW CT02B Events ........................................................................... 7-61 7.13.8 ESW HOV-074 Events ....................................................................... 7-62 v Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.13.9 Total ESW Pump Events Summary .................................................... 7-62 7.13.10 Total ESW Cooling Tower Events Summary ..................................... 7-63 7.14 ECW Events ...................................................................................................... 7-63 7.14.1 ECW Pump PP02A Events ................................................................. 7-63 7.14.2 ECW Pump PP02B Events ................................................................. 7-64 7.14.3 Total ECW Pump Event Summary ..................................................... 7-65 7.15 SCRAM Due To Mechanical Failure Events .................................................... 7-65 7.16 Control Software Events ................................................................................... 7-66 7.16.1 PPS Loop Controller Application Software Events ............................ 7-66 7.16.2 PPS Group Controller Application Software Events .......................... 7-67 7.16.3 PPS Loop Controller Operating System Software Events .................. 7-67 7.17 Main Steam Events ........................................................................................... 7-68 7.17.1 Main Steam Atmospheric Dump Valve (V-102) ................................ 7-68 7.17.2 Main Steam Isolation Valves .............................................................. 7-68 7.17.3 Main Steam Safety Valves .................................................................. 7-69 7.18 TGBCCW Events .............................................................................................. 7-69 7.18.1 TGBCCW Pump Train 2 Events ........................................................ 7-69 7.19 Shutdown Cooling System (SDC) Events ........................................................ 7-70 7.19.1 SDC Pump PP01A Events .................................................................. 7-70 7.19.2 SDC Pump PP01B Events .................................................................. 7-71 7.19.3 Total SDC Pump Event Summary ...................................................... 7-71

8. SAMDA COST EVALUATION ............................................................................... 8-1 8.1 Emergency Diesel Generator Events .................................................................. 8-1 8.2 AAC CTG Events ............................................................................................... 8-1 8.3 Auxiliary Feedwater Events ................................................................................ 8-1 8.3.1 AFW Isolation Valve Events ................................................................ 8-1 8.3.2 AFW Pump Events ............................................................................... 8-2 8.4 Fire Barrier Failure Events .................................................................................. 8-2 8.5 CCW Events ........................................................................................................ 8-3 8.5.1 CCW Pump Events ............................................................................... 8-3 vi Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 8.5.2 CS Heat Exchanger Isolation Valves .................................................... 8-3 8.6 Containment Spray Events .................................................................................. 8-4 8.6.1 Containment Spray Pump Events ......................................................... 8-4 8.6.2 Containment Spray Header Isolation Valves ........................................ 8-4 8.6.3 Containment Spray Heat Exchangers ................................................... 8-5 8.7 125 VDC Power Events ...................................................................................... 8-5 8.8 120 VAC Power Events ...................................................................................... 8-5 8.9 AC Power Events ................................................................................................ 8-6 8.9.1 SAT Events ........................................................................................... 8-6 8.9.2 4.16KV Circuit Breaker Events ............................................................ 8-6 8.10 POSRV Events .................................................................................................... 8-7 8.11 Chiller/Cooler Events .......................................................................................... 8-7 8.12 Safety Injection System Events........................................................................... 8-7 8.12.1 Safety Injection Pump Events ............................................................... 8-7 8.12.2 IRWST Strainer .................................................................................... 8-8 8.12.3 Safety Injection Recirculation Valve .................................................... 8-8 8.13 ESW Events ........................................................................................................ 8-8 8.13.1 ESW Filter Events ................................................................................ 8-8 8.13.2 ESW Pump Events ................................................................................ 8-9 8.13.3 ESW Cooling Towers ........................................................................... 8-9 8.13.4 ESW Cooling Tower Return Valve ...................................................... 8-9 8.14 ECW Pumps ...................................................................................................... 8-10 8.15 SCRAM Due To Mechanical Failure Events .................................................... 8-10 8.16 Control Software Events ................................................................................... 8-10 8.17 Main Steam Events ........................................................................................... 8-11 8.17.1 ADVs .................................................................................................. 8-11 8.17.2 MSIVs ................................................................................................. 8-11 8.17.3 MSSVs ................................................................................................ 8-11 8.18 TGBCCW Pump ............................................................................................... 8-11 8.19 Shutdown Cooling System Pumps .................................................................... 8-12 vii Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

9. SAMDA COST-BENEFIT EVALUATION............................................................. 9-1 9.1 Emergency Diesel Generator Events .................................................................. 9-1 9.2 AAC Combustion Turbine Generator Events ..................................................... 9-1 9.3 Auxiliary Feedwater Events ................................................................................ 9-2 9.3.1 AFW Isolation Valve Events ................................................................ 9-2 9.3.2 AFW Pumps .......................................................................................... 9-2 9.3.3 Startup FW Pump PP07 Events ............................................................ 9-2 9.4 Fire Barrier Failure Events .................................................................................. 9-3 9.5 Component Cooling Water (CCW) Events ......................................................... 9-3 9.5.1 DG001A CCW Inlet Valve MOV-191 ................................................. 9-3 9.5.2 CCW Pumps ......................................................................................... 9-3 9.5.3 CS Heat Exchanger Isolation Valves .................................................... 9-4 9.6 Containment Spray (CS) Events ......................................................................... 9-4 9.6.1 Containment Spray Pumps.................................................................... 9-4 9.6.2 Total Containment Spray Isolation Valve Event Summary.................. 9-4 9.6.3 Containment Spray Heat Exchangers ................................................... 9-5 9.7 125 VDC Power Events ...................................................................................... 9-5 9.8 120 VAC Power Events ...................................................................................... 9-5 9.9 AC Power Events ................................................................................................ 9-6 9.9.1 SAT Transformers ................................................................................ 9-6 9.9.2 4.16KV Circuit Breakers ...................................................................... 9-6 9.10 POSRVs .............................................................................................................. 9-6 9.11 Chiller/Cooler Events .......................................................................................... 9-7 9.11.1 ECW Chiller Summary ......................................................................... 9-7 9.11.2 EDG Room Cubical Coolers................................................................. 9-7 9.11.3 Motor Driven AFW Pump Room Cubical Coolers .............................. 9-7 9.11.4 Air Handling Units................................................................................ 9-8 9.12 Safety Injection (SI) Events ................................................................................ 9-8 9.12.1 SI Pumps PP02D Events ....................................................................... 9-8 9.12.2 IRWST Strainer Events ........................................................................ 9-8 viii Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.12.3 SI Valve V-959 Events ......................................................................... 9-9 9.13 ESW Events ........................................................................................................ 9-9 9.13.1 ESW Filter Plugging Events ................................................................. 9-9 9.13.2 ESW HOV-074 ..................................................................................... 9-9 9.13.3 ESW Pumps ........................................................................................ 9-10 9.13.4 Total ESW Cooling Tower Events Summary ..................................... 9-10 9.14 ECW Pumps ...................................................................................................... 9-10 9.15 SCRAM Due To Mechanical Failure................................................................ 9-11 9.16 Control Software ............................................................................................... 9-11 9.16.1 PPS Loop Controller Application Software........................................ 9-11 9.16.2 PPS Group Controller Application Software ...................................... 9-11 9.16.3 PPS Loop Controller Operating System Software .............................. 9-11 9.17 Main Steam Events ........................................................................................... 9-12 9.17.1 Main Steam Atmospheric Dump Valve (V-102) ................................ 9-12 9.17.2 Main Steam Isolation Valves .............................................................. 9-12 9.17.3 Main Steam Safety Valves .................................................................. 9-12 9.18 TGBCCW Events .............................................................................................. 9-13 9.18.1 TGBCCW Pump Train 2 Events ........................................................ 9-13 9.19 Shutdown Cooling System (SDC) Events ........................................................ 9-13 9.19.1 SDC Pumps ......................................................................................... 9-13

10. SENSITIVITY ANALYSIS (THREE-PERCENT DISCOUNT RATE) ............. 10-1 10.1 Averted Public Exposure (APE) ....................................................................... 10-2 10.1.1 APE for At-Power Internal Events ..................................................... 10-3 10.1.2 APE for At-Power Internal Flooding Events ...................................... 10-3 10.1.3 APE for At-Power Internal Fire Events .............................................. 10-3 10.1.4 APE for LPSD Internal Events ........................................................... 10-3 10.1.5 APE for LPSD Flooding Events ......................................................... 10-3 10.1.6 APE for LPSD Fire Events ................................................................. 10-3 10.1.7 Total APE ........................................................................................... 10-4 10.2 Averted Public Offsite Property Damage Costs (AOC) ................................... 10-4 ix Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.2.1 AOC for At-Power Internal Events..................................................... 10-4 10.2.2 AOC for At-Power Internal Flooding Events ..................................... 10-4 10.2.3 AOC for At-Power Internal Fire Events ............................................. 10-5 10.2.4 AOC for LPSD Internal Events .......................................................... 10-5 10.2.5 AOC for LPSD Flooding Events ........................................................ 10-5 10.2.6 AOC for LPSD Fire Events ................................................................ 10-5 10.2.7 Total AOC........................................................................................... 10-5 10.3 Averted Occupational Exposure (AOE) ........................................................... 10-5 10.3.1 Averted Immediate Occupational Exposure Costs ............................. 10-6 10.3.2 Averted Long-Term Occupational Exposure Costs ............................ 10-7 10.3.3 Total Averted Occupational Exposure Costs ...................................... 10-9 10.4 Averted Onsite Costs (AOSC) ........................................................................ 10-10 10.4.1 Averted Cleanup and Decontamination Costs .................................. 10-11 10.4.2 Averted Replacement Power Costs................................................... 10-13 10.4.3 Averted Repair and Refurbishment Costs......................................... 10-15 10.4.4 Total Averted Onsite Costs (AOSC) ................................................ 10-15 10.5 Cost Enhancement (COE) ............................................................................... 10-16 10.6 Total Unmitigated Baseline Risk .................................................................... 10-16

11. CONCLUSIONS ....................................................................................................... 11-1

12. REFERENCES ......................................................................................................... 12-1 x Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification LIST OF TABLES NUMBER TITLE PAGE Table 1a Base Case - Source Term Category Summary for At-Power Events .............. T-1 Table 1b Base Case - Source Term Category Summary for Low Power Shutdown Events .................................................................... T-2 Table 2 Representative Accident Sequences for each STC .......................................... T-3 Table 3a Offsite Exposure By Source Term Category for At-Power Internal Events ........................................................................... T-4 Table 3b Offsite Exposure By Source Term Category for At-Power Internal Flooding ....................................................................... T-5 Table 3c Offsite Exposure By Source Term Category for At-Power Internal Fire ............................................................................... T-6 Table 3d Offsite Exposure By Source Term Category for Low Power Shutdown Internal Events....................................................... T-7 Table 3e Offsite Exposure By Source Term Category for Low Power Shutdown Internal Flooding ................................................... T-8 Table 3f Offsite Exposure By Source Term Category for Low Power Shutdown Internal Fire ........................................................... T-9 Table 4a Offsite Property Damage Costs By Source Term Category for At-Power Internal Events ......................................................................... T-10 Table 4b Offsite Property Damage Costs By Source Term Category for At-Power Internal Flooding ..................................................................... T-11 Table 4c Offsite Property Damage Costs By Source Term Category for At-Power Internal Fire ............................................................................. T-12 Table 4d Offsite Property Damage Costs By Source Term Category for Low Power Shutdown Internal Events..................................................... T-13 Table 4e Offsite Property Damage Costs By Source Term Category for Low Power Shutdown Internal Flooding ................................................. T-14 xi Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4f Offsite Property Damage Costs By Source Term Category for Low Power Shutdown Internal Fire ......................................................... T-15 Table 5 Initial List of Candidate Improvements for the APR1400 SAMDA Analysis.............................................................. T-16 Table 6a List of Basic Events from APR1400 PRA CDF Importance Analysis (At-Power Internal Events) ................................. T-35 Table 6b List of Basic Events from APR1400 PRA CDF Importance Analysis (At-Power Internal Flooding Events) ................. T-46 Table 6c List of Basic Events from APR1400 PRA CDF Importance Analysis (At-Power Internal Fire Events) ......................... T-55 Table 6d List of Basic Events from APR1400 PRA CDF Importance Analysis (LPSD Internal Events)....................................... T-64 Table 6e List of Basic Events from APR1400 PRA CDF Importance Analysis (LPSD Internal Flooding Events) ....................... T-69 Table 6f List of Basic Events from APR1400 PRA CDF Importance Analysis (LPSD Internal Fire Events) ............................... T-75 Table 7a List of Additional Basic Events from APR1400 PRA Cutset Review (At-Power Internal Events) ............................................................................ T-80 Table 7b List of Additional Basic Events from APR1400 PRA Cutset Review (At-Power Internal Flooding Events) ............................................................ T-82 Table 7c List of Additional Basic Events from APR1400 PRA Cutset Review (At-Power Internal Fire Events) .................................................................... T-83 Table 7d List of Additional Basic Events from APR1400 PRA Cutset Review (LPSD Internal Events).................................................................................. T-85 Table 7e List of Additional Basic Events from APR1400 PRA Cutset Review (LPSD Internal Flooding Events) .................................................................. T-89 Table 7f List of Additional Basic Events from APR1400 PRA Cutset Review (LPSD Internal Fire Events) .......................................................................... T-90 xii Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification ACRONYMS AND ABBREVIATIONS The following is a list of acronyms and abbreviations used in this report. These abbreviations may be used in the chapter without an opening declaration of their meaning in the text of their definition (although one is usually provided).

AC alternating current AFW auxiliary feedwater AFWST auxiliary feedwater storage tank AMSAC ATWS mitigation system actuation circuitry AOC averted offsite property damage costs AOE averted occupational exposures AOSC averted onsite costs AOV air-operated valve APE averted public exposure APR advanced power reactor APR1400 Advanced Power Reactor 1400 ATWS anticipated transient without scram CDF core damage frequency CE Combustion Engineering CFR Code of Federal Regulations CO2 carbon dioxide COE cost of enhancement CST condensate storage tank dc direct current DC Design Certification ECCS emergency core cooling system ECW essential chilled water EDG emergency diesel generator EOP emergency operating procedure ESRP environmental standard review plan ESW essential service water xiii Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification FV Fussell-Vesely GSI generic safety issue H2 hydrogen HP/LP high pressure/low pressure HVAC heating, ventilation, and air conditioning HVT holdup volume tank IRWST in-containment refueling water storage tank ISLOCA interfacing system loss-of-coolant accident KEPCO Korea Electric Power Corporation KHNP Korea Hydro & Nuclear Power, Inc.

LOCA loss-of-coolant accident LOOP loss-of-offsite power LPSD low power and shutdown MCR main control room MSIV main steam isolation valve NEI Nuclear Energy Institute NEPA National Environmental Policy Act NPV net present value NRC U.S. Nuclear Regulatory Commission NUREG U.S. Nuclear Regulatory Commission Regulation P&ID piping and instrument diagram POSRV pilot-operated safety relief valve PRA probabilistic risk assessment PV present value PW present worth RCP reactor coolant pump REM roentgen equivalent man RHR residual heat removal RPV reactor pressure vessel SAMA severe accident mitigation alternative xiv Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification SAMDA severe accident mitigation design alternative SBO station blackout SG steam generator SGTR steam generator tube rupture SI safety injection SLC secondary liquid control SRV safety relief valve SSC structure, system, or component STC source term category SW service water U.S.C. U.S. Code xv Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 1 INTRODUCTION This report provides an evaluation of severe accident mitigation design alternatives (SAMDA) for the APR1400 design. This evaluation is performed to address the potential costs and benefits of SAMDAs for the APR1400 design. Consideration of SAMDAs included identifying a broad range of potential alternatives and then determining whether implementation of the alternative would be feasible and beneficial on a cost-risk reduction basis.

The methods used to identify, screen, and evaluate SAMDAs for the APR1400 Design Certification are described.

This report also describes the calculation of the monetary value of unmitigated base risk and the results of an evaluation of the maximum risk reduction that would be expected from implementing a risk reduction strategy.

This report was developed to conform with the following regulations:

Section 102 of the National Environmental Policy Act of 1969, as amended (42 U.S.C. § 4332), which requires in part that:

all agencies of the Federal Government shall (C) include in every recommendation or report on proposals for legislation and other major Federal actions significantly affecting the quality of the human environment, a detailed statement by the responsible official on (iii) alternatives to the proposed action.

10 CFR 52.47(b)(2), which requires that the application include an environmental report as required by 10 CFR 51.55.

10 CFR 51.55(a), which states that:

[e]ach applicant for a standard design certification shall submit with its application a separate document entitled, Applicants Environmental Report Standard Design Certification. The environmental report must address the costs and benefits of severe accident mitigation design alternatives and the bases for not incorporating severe accident mitigation design alternatives in the design to be certified.

1-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 2 METHODOLOGY The acceptance criterion for severe accident mitigation alternatives (SAMAs) is provided in Section 7.3 of NUREG-1555, Environmental Standard Review Plan - Severe Accident Mitigation Alternatives (Reference 4), as follows:

Completeness and reasonableness, also with respect to the following: (1) the identification of SAMAs applicable to the plant or design under consideration, (2) the estimation of core damage frequency reduction and averted person-rem for each SAMA, (3) the estimation of cost for each SAMA, (4) the ranking of value-impact screening criteria to identify SAMAs for further consideration, and (5) the final disposition of promising SAMAs.

The evaluation of SAMDAs for the APR1400 design certification consists of the steps listed below in conformance with the acceptance criterion described above. The sections of this report where the steps are described are also provided. Consideration of alternatives to mitigate severe accidents involves the following steps.

1. Determine the base risk presented to the surrounding population and environment from plant operation (Section 3).

2. Calculate the monetary value of the unmitigated base risk (Section 4).

3. Identify potential SAMDAs (Section 5).

4. Screen the identified potential SAMDAs for applicability to APR1400 and the feasibility of implementing them (Section 6).

5. Evaluate the SAMDAs not screened out in Step #4 to determine the expected benefits of implementing them (Section 7).

6. Estimate the cost of implementing the SAMDAs that were evaluated in Step #5 (Section 8).

7. Compare the estimated costs to the expected benefits to determine whether implementing any potential SAMDA would be cost-beneficial (Section 9).

8. Evaluate how uncertainties could affect the cost-benefit analyses.

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APR1400 Applicants Environmental Report - Standard Design Certification

9. Perform a sensitivity analysis of the results (Section 10).

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APR1400 Applicants Environmental Report - Standard Design Certification 3 BASE RISK Base risk is defined as the maximum possible averted risk. Determination of base risk, as well as the overall SAMDA evaluation process, is detailed in Reference 3 and described below. The first step to determine base risk is to develop and quantify the risk that could be presented by operation of an APR1400 reactor. Risk is calculated using a Level 1 and Level 2 probabilistic risk assessment (PRA) model. The results of that model provide overall risk measured by core damage frequency (CDF) and the characteristics of any expected radionuclide release following a severe accident.

The APR1400 Level 1 PRA model quantified at-power internal events, at-power internal fire, at-power internal flooding, and low-power and shutdown (LPSD) internal events, LPSD fire event, and LPSD internal flooding events. Risk from other external events, for example, high winds, seismic events, etc., was determined to be negligible.

From Table 19.1-30 of the DCD, total CDF from the at-power internal events PRA is 1.0x10-6 per year and is calculated as the sum of the 21 source term categories (STCs) calculated from the Level 2 PRA model.

From Table 19.1-30b of the DCD, total CDF from internal flooding events is 3.8x10-7 per year.

From Table 19.1-30a of the DCD, fire-induced accident sequences had a calculated CDF of 2.8x10-6 per year.

LPSD internal event accident sequences had a calculated CDF of 1.9x10-6 per year (Reference 3)

LPSD internal flood events had a CDF of 8.1x10-8 per year (Reference 3)

LPSD internal fire events had a CDF of 1.5x10-6 per year (Reference 3).

Summing the previous values gives a total CDF of 7.7x10-6 per year.

Using the results of the Level 1 PRA, the second step in determining base risk is to identify the characteristics of any expected radionuclide release following a severe accident and then to quantify the expected frequency of release. The APR1400 Level 2 PRA model characterizes releases into 21 STCs. Each of the STCs is distinguished by the magnitude of 3-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification fission products released, the timing of the fission product release, and the pathway for the release. The STC definitions and contributions to risk are presented in Tables 1a and 1b.

A subset of the STCs is considered to result in large releases. DCD Section 19.1.4.2.1.3 presents the definition of a large release and Table 19.1-29 delineates the STCs that are considered large release. All fission product releases are included in the SAMDA analysis regardless of whether the release is large or not. Therefore, the definition of large is not germane to this analysis. Details of how accident sequences are binned into each STC are provided in that section of the DCD as well as the criteria used to select the accident sequence used to represent each STC. The representative accident sequence for each STC, taken from Reference 3, are presented in Table 2.

The principal phenomena considered in WinMACCS are atmospheric transport, mitigative actions based on dose projections, dose accumulation by a number of pathways including food and water ingestion, early and latent health effects, and economic costs. The specific atmospheric, surface water and groundwater pathways inputs to the model for this representative site location are those specified in the Surry site data file documented in the Level 3 analysis (Appendix A of Reference 3) and provided with WinMACCS.

The results with respect to the above pathways are documented in the WinMACCS analysis output files (Appendix A of Reference 3).

For each STC, representative releases are determined and timing and release characteristic information for representative fission product groups are developed. The representative sequences for each STC are summarized in Table 2 of Reference 3. This information is then used to approximate the radiological release plumes used in the Level 3 analysis.

The Level 3 analysis uses the MACCS code while the Level 2 PRA used the MAAP code to develop fission product releases. Mapping of the MAAP fission product release categories to the MACCS fission product release categories is shown in Reference 6.

Also shown in Reference 6 is the basis and development of the plume segments for input to the MACCS code.

Offsite consequences are calculated from the Level 3 PRA analysis. The Level 3 (WinMACCS) model has been prepared for a representative year when the APR1400 design could be operated. If the design certification (DC) is received in 2020, a combined operating license application (COLA) could be received within several years of the DC.

To be conservative, however, this analysis assumes that any licensing action with respect to 3-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification a COLA would not occur for ten years after the date that the DC is received thus allowing for larger population growth. The year 2030 is considered reasonable for being within five years of any licensing action with respect to the APR1400 design.

Thus, the Level 3 PRA model was prepared using projected year 2030 demographic data from the 2010 US Census and 2007 Agricultural Census for the area around the Surry site and APR1400-DC source term results from the Level 2 MAAP analysis.

The Level 3 PRA is based on the Surry site model documented in NUREG-1150 as a representative site. The model uses the following meteorological, population, and land use data inputs to represent the reference site location for the analysis:

The meteorological data file used was the sample meteorological data file provided with the WinMACCS software NRC sample problems. The data describes one years (1988) worth of hourly meteorological data for the site as recorded at the site meteorological tower. The data is considered representative of any year for the Surry reference site.

This analysis uses the Surry 80.47 km (50 mile) population data projected for year 2030, which were obtained from the 2010 Census data for the region surrounding the site.

SECPOP was used to calculate the land fraction for each rosette section as explained in the manual for the code. The code contains a county-level database with the land fractions for each county obtained from the 2010 Census data files. The calculated values are used directly in these analyses. Due to the way in which SECPOP allocates population from the census blocks, certain radial blocks near the plant are shown as all water. These segments have zero population so that the effect on the results is not significant.

The region indexes were selected to allow unique region numbers for the sectors with large areas, that is, the very small regions of the rosette near the plant were assigned to similar regions.

For the representative site at Surry, the original watershed indexes for the Surry site were used directly in this analysis. These values were chosen to more accurately model the landmass and bodies of water surrounding the site up to the 50-mile radius of this analysis.

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APR1400 Applicants Environmental Report - Standard Design Certification

The crop season data was taken from the NUREG-1150 analysis for the Surry reference site. Agricultural data available in the 1997 Census of Agriculture was used to produce the land fraction used for each crop.

The watershed definition data was assumed to be the same as for the Surry site and is taken from the NUREG-1150 analysis for Surry.

The regional economic data was calculated by SECPOP from data provided to it in a data file named County1997RG.dat. This file was updated (a pre-processing step) to 2007 for the 45 counties and independent cities that are all or in part within 50 miles of the Surry site. The other some 3000 county data sets in the file for the rest of the US were left unchanged.

The selected SECPOP regional economic values were updated to 2007 using data from the Bureau of the Census and the Department of Agriculture 2007 Census of Agriculture.

For each STC, the Level 3 PRA provides values for the conditional offsite dose and conditional offsite property damage that would result given that a fission product release with the plume characteristics used to represent the source term occurred. The total expected dose consequence is obtained by multiplying the conditional offsite dose by the expected frequency for each STC, then summing the expected doses for all STCs. The conditional dose and expected dose for each STC along with the total expected dose are shown in Tables 3a through 3f. Similarly, the total expected property damage is obtained by multiplying the conditional property damage value by the expected frequency for each STC, then summing the expected property damage values for all STCs. The conditional property costs and expected property costs for each STC along with the total expected property costs are shown in Tables 4a through 4f.

Details of the socioeconomic, individual, and population health risks attributed to the postulated APR1400-DC severe accident analysis are documented in the WinMACCS output files.

3-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4 UNMITIGATED RISK MONETARY VALUE The unmitigated risk monetary value is calculated using the methodology given in NEI 05-01 (Reference 1) for the performance of cost-benefit analyses. The value of unmitigated risk can be used to represent the maximum benefit that could be achieved if all risk was eliminated for at-power events. The methodology of NEI 05-01 determines the present worth net value of public risk according to the following formula:

NPV = (APE + AOC + AOE + AOSC) - COE (1)

Where:

NPV = present value of current risk ($),

APE = present value of averted public exposure ($),

AOC = present value of averted offsite property damage costs ($),

AOE = present value of averted occupational exposure ($),

AOSC = present value of averted onsite costs ($),

COE = cost of any enhancement implemented to reduce risk ($).

The derivation of each of these costs is described in the subsections below. All equations used in the subsections below are taken from NUREG/BR-0184 (Reference 2), which is the basis for the equations given in NEI 05-01 (Reference 1).

The following specific values were used for various terms in the analyses:

Present Worth

The present worth (PW) was determined by:

1 e rt PW =

r (2)

Where:

r is the discount rate = 7% per year (assumed throughout these analyses) t is the plant life = 60 years 4-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification PW is the present worth of a string of annual payments of one dollar

= $14.07 Dollars per REM The conversion factor used for assigning a monetary value to averted onsite and offsite exposures is $2,000/person-rem averted. This is consistent with the NRCs regulatory analysis guidelines presented in and used throughout NEI 05-01.

4.1 Averted Public Exposure (APE)

Expected offsite doses from the internal events PRA accident sequences are presented in Tables 3a through 3f. Costs associated with these doses were calculated using the following equation:

rt f 1 e APE = (FS DPS FA DPA )R r (3)

Where:

APE = present value of averted public exposure ($),

R = monetary equivalent of unit dose ($2,000/person-rem),

FS = baseline accident frequency (events per year from Tables 3a through 3f),

FA = accident frequency after mitigation (0 events per year),

FSDPS = baseline accident offsite dose frequency (person-rem per year from Tables 3a through 3f),

FADPA = accident offsite dose frequency after mitigation (0 person-rem per year),

r = real discount rate (7% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, APE is calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.1.1 APE for At-Power Internal Events APE(IE) = (5.33x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.07x60))/(0.07 per year))

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= $15,000 4.1.2 APE for At-Power Internal Flooding Events APE(Fld) = (5.51x10-2 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.07x60))/(0.07 per year))

= $1,551 4.1.3 APE for At-Power Internal Fire Events APE(Fire) = (5.79x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e - (0.07x60))/(0.07 per year))

= $16,294 4.1.4 APE for LPSD Internal Events APE(SDIE) = (3.34x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e - (0.07x60))/(0.07 per year))

= $9,399 4.1.5 APE for LPSD Flooding Events APE(SDFld) = (1.40x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e - (0.07x60))/(0.07 per year))

= $3,946 4.1.6 APE for LPSD Fire Events APE(SDFire)= (1.31x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.07x60))/(0.07 per year))

= $3,687 4.1.7 Total APE APETot = APE(IE) + APE(Fld) + APE(Fire) + APE(SDIE) + APE(SDFld) + APE(SDFire) 4-3 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

= $15,000 + $1,551 + $16,294 +$ 9,399 + $3,946 + $3,687

= $49,877 4.2 Averted Offsite Property Damage Costs (AOC)

Annual expected offsite economic risk is shown in Tables 4a through 4f. The costs associated with AOC were calculated using the following equation:

rt f 1 e AOC = (FS PDS F A PDA )

r (4)

Where:

AOC = present value of averted offsite property damage costs ($),

FSPDS = baseline accident frequency

property damage (cost per year from Tables 4a through 4f),

FAPDA = accident frequency

property damage after mitigation (0 events per year),

r = real discount rate (7% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, AOC is calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.2.1 AOC for At-Power Internal Events AOC(IE) = ($1,534 per year - 0) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $21,580 4.2.2 AOC for At-Power Internal Flooding Events AOC(Fld) = ($142 per year - 0) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $1,992 4-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.2.3 AOC for At-Power Internal Fire Events AOC(Fire) = ($1,355 per year - 0) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $19,070 4.2.4 AOC for LPSD Internal Events AOC(SDIE) = ($883 per year - 0) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $12,422 4.2.5 AOC for LPSD Flooding Events AOC(SDFld)= ($314 per year - 0) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $4,423 4.2.6 AOC for LPSD Fire Events AOC(SDFire)= ($316 per year - 0) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $4,446 4.2.7 Total AOC AOCTot = AOC(IE) + AOC(Fld) + AOC(Fire) + AOC(SDIE) + AOC(SDFld) + AOC(SDFire)

= $21,580 + $1,992 + $19,070 + $12,422 + $4,423 + $4,446

= $63,933 4.3 Averted Occupational Exposure (AOE)

There are two types of occupational exposure due to accidents: immediate and long-term.

Immediate exposure occurs at the time of the accident and during the management of the emergency. Long-term exposure is associated with the cleanup and refurbishment or decommissioning of the damaged facility. The value of avoiding both types of exposure is considered when evaluating risk.

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APR1400 Applicants Environmental Report - Standard Design Certification The occupational exposure associated with severe accidents is assumed to be 23,300 person-rem/accident. This value includes a short-term component of 3,300 person-rem/accident and a long-term component of 20,000 person-rem/accident. These estimates are consistent with the best estimate values presented in Section 5.7.3 of NUREG/BR-0184 (Reference 2). In calculating base risk, the accident-related onsite exposures were calculated using the best estimate exposure components applied over the onsite cleanup period. For onsite cleanup, the accident-related onsite exposures were calculated over a 10-year cleanup period. Costs associated with immediate dose, long-term dose and total dose are calculated below for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events.

4.3.1 Averted Immediate Occupational Exposure Costs Per the guidance of NEI 05-01, costs associated with immediate occupational doses from an accident were calculated using the following equation:

rt f 1 e W IO = (FS D IOS FA D IOA )R r (5)

Where:

WIO = present value of averted immediate occupational exposure ($),

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

DIOS = baseline expected immediate onsite dose (3,300 person-rem/event),

DIOA = expected occupational exposure after mitigation (3,300 person-rem/event),

R = monetary equivalent of unit dose ($2,000/person-rem),

r = real discount rate (7% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, WIO is calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

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APR1400 Applicants Environmental Report - Standard Design Certification 4.3.1.1 WIO for At-Power Internal Events WIO(IE) = ((1.00x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $93 4.3.1.2 WIO for At-Power Internal Flooding Events WIO(Fld) = ((3.82x10-7 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $35 4.3.1.3 WIO for At-Power Internal Fire Events WIO(Fire) = ((2.79x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $259 4.3.1.4 WIO for LPSD Internal Events WIO(SDIE) = ((1.94x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $180 4.3.1.5 WIO for LPSD Flooding Events WIO(SDFld) = ((8.06x10-8 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $7 4.3.1.6 WIO for LPSD Fire Events WIO(SDFire) = ((1.48x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.07 x 60)) / (0.07 per year)

= $137 4-7 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.3.2 Averted Long-Term Occupational Exposure Costs Per the guidance of NUREG/BR-0184, costs associated with long-term occupational doses from an accident were calculated using the following equation:

rt f 1 e 1 e rm W LTO = (FS D LTOS FA D LTOA )R *

r rm (6)

Where:

WLTO = present value of averted long-term occupational exposure ($),

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

DLTOS = baseline expected long-term onsite dose (20,000 person-rem/event),

DLTOA = expected occupational exposure after mitigation (20,000 person-rem/event),

R = monetary equivalent of unit dose ($2,000/person-rem),

r = real discount rate (7% per year),

m = years over which long-term doses accrue (10 years from Reference 2),

tf = years remaining until end of plant life (60 years).

Using the values given above, WLTO is calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.3.2.1 WLTO for At-Power Internal Events WLTO(IE) = ((1.00x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.07 x 60)) / (0.07 per year) x ((1 - e - (0.07 x 10)) / ((0.07 per year) x (10 years))

= $405 4-8 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.3.2.2 WLTO for At-Power Internal Flooding Events WLTO(Fld) = ((3.82x10-7 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.07 x 60)) / (0.07 per year) x ((1 - e - (0.07 x 10)) / ((0.07 per year) x (10 years))

= $155 4.3.2.3 WLTO for At-Power Internal Fire Events WLTO(Fire) = ((2.79x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.07 x 60)) / (0.07 per year) x ((1 - e - (0.07 x 10)) / ((0.07 per year) x (10 years))

= $1,129 4.3.2.4 WLTO for LPSD Internal Events WLTO(SDIE)= ((1.94x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.07 x 60)) / (0.07 per year) x ((1 - e - (0.07 x 10)) / ((0.07 per year) x (10 years))

= $785 4.3.2.5 WLTO for LPSD Flooding Events WLTO(SDFld)= ((8.06x10-8 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.07 x 60)) / (0.07 per year) x ((1 - e - (0.07 x 10)) / ((0.07 per year) x (10 years))

= $33 4.3.2.6 WLTO for LPSD Fire Events WLTO(SDFire)= ((1.48x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.07 x 60)) / (0.07 per year) x ((1 - e - (0.07 x 10)) / ((0.07 per year) x (10 years))

= $599 4-9 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.3.3 Total Averted Occupational Exposure Costs As described in Section 4.3, the total cost associated with averted occupational exposure (AOE) is the sum of the costs associated with averted immediate exposure and the costs associated with the averted long-term exposure:

AOE = WIO + WLTO (7)

Total averted onsite exposure costs are calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.3.3.1 AOE for At-Power Internal Events AOE(IE) = $ 93 + $ 405 = $498 4.3.3.2 AOE for At-Power Internal Flooding Events AOE(Fld) = $ 35 + $ 155 = $190 4.3.3.3 AOE for At-Power Internal Fire Events AOE(Fire) = $ 259 + $ 1,129 = $1,388 4.3.3.4 AOE for LPSD Internal Events AOE(SDIE) = $ 180 + $ 785 = $965 4.3.3.5 AOE for LPSD Flooding Events AOE(SDFld) = $ 7 + $ 33 = $40 4.3.3.6 AOE for LPSD Fire Events AOE(SDFire)= $ 137 + $ 599 = $736 4.3.3.7 Total AOE AOE Tot = AOE(IE) + AOE(Fld) + AOE(Fire) + AOE(SDIE) + AOE(SDFld) + AOE(SDFire)

= $498 + $190 + $1,388 + $965 + $40 + $736 4-10 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

= $3,817 4.4 Averted Onsite Costs (AOSC)

NUREG/BR-0184 defines three types of costs associated with onsite property damage from an accident: cleanup and decontamination, long-term replacement power, and repair and refurbishment. The value of avoiding each of these type of costs is considered when evaluating risk. Total averted onsite property damage costs are the sum of these three types of costs. Calculation of onsite property damage costs is detailed in the sections that follow.

4.4.1 Averted Cleanup and Decontamination Costs The estimated cleanup cost for severe accidents is defined in NUREG/BR-0184, Section 5.7.6.1, to be $1.5109/accident (undiscounted). Using the value of $1.5109/event and assuming, as in NUREG/BR-0184, that the total sum is paid in equal installments over a 10 year period, the present value of those ten payments for cleanup and decontamination costs can be calculated as follows:

C 1 e rm PVCD = CD m r (8)

Where:

PVCD = present value of averted onsite cleanup costs exposure over cleanup period ($),

CCD = total value of averted onsite cleanup costs ($),

r = real discount rate (7% per year),

m = years over which long-term doses accrue (10 years),

PVCD = (($1.5109/event) / (10 years)) * ((1 - e-(0.07*10)) / 0.07),

PVCD = $1.08109.

The present value of the costs over the cleanup period is considered over the period of the plant life. The net present value of averted cleanup costs over the plant life can be calculated using the following equation:

rt f 1 e U CD = (FS FA ) PVCD r (9) 4-11 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Where:

UCD = present value of averted onsite cleanup costs ($),

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

PVCD = present value of averted onsite cleanup costs exposure over cleanup period ($),

r = real discount rate (7% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, UCD is calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.4.1.1 UCD for At-Power Internal Events UCD(IE) = (1.00x10-6 events per year - 0) x ($1.0787x109) x (1 - e - (0.07 x 60))

/ (0.07 per year)

= $15,178 4.4.1.2 UCD for At-Power Internal Flooding Events UCD (Fld) = (3.82x10-7 events per year - 0) x ($1.0787x109) x (1 - e - (0.07 x 60))

/ (0.07 per year)

= $5,798 4.4.1.3 UCD for At-Power Internal Fire Events UCD (Fire) = (2.79x10-6 events per year - 0) x ($1.0787x109) x (1 - e - (0.07 x 60))

/ (0.07 per year)

= $42,348 4.4.1.4 UCD for LPSD Internal Events UCD (SDIE) = (1.94x10-6 events per year - 0) x ($1.0787x109) x (1 - e - (0.07 x 60))

/ (0.07 per year) 4-12 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

= $29,446 4.4.1.5 UCD for LPSD Flooding Events UCD (SDFld) = (8.06x10-8 events per year - 0) x ($1.0787x109) x (1 - e - (0.07 x 60))

/ (0.07 per year)

= $1,223 4.4.1.6 UCD for LPSD Fire Events UCD (SDFire)= (1.48x10-6 events per year - 0) x ($1.0787x109) x (1 - e - (0.07 x 60))

/ (0.07 per year)

= $22,464 4.4.2 Averted Replacement Power Costs Replacement power costs, URP, are an additional contributor to onsite costs and can be calculated in accordance with NUREG/BR-0184, Section 5.7.6.2. Since replacement power will be needed for that time period following a severe accident until the end of the expected generating plant life, long-term power replacement calculations have been used. APR1400 is expected to have a net electrical output of 1,400 MWe.

Replacement power cost calculations performed in NUREG/BR-0184 are based on the 910 MWe reference plant. In applying the methodology used in NUREG/BR-0184 to the APR1400 design, the equation was scaled for the 1,400 MWe output of the APR1400 design. For discount rates between 5 percent and 10 percent, NUREG/BR-0184 recommends that the present value of replacement power be calculated as follows:

(Rated power)

($1.2E + 8 )

PV RP =

r (910MWe)

( rt 1 e f )2 (10)

Where:

PVRP = present value of replacement power for a single event ($),

r = real discount rate (7% per year),

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APR1400 Applicants Environmental Report - Standard Design Certification tf = years remaining until end of plant life (60 years),

Rated power = 1,400 MWe.

Using the values given above:

PVRP = ((1.2 x 108 x (1,400 MWe / 910 MWe)) / (0.07 per year)x (1 - e-(0.0 7 x 60) 2

)

PVRP = $2.56 x 109 The replacement power costs PVRP ($2.56 x 109) was adjusted to 2016 dollars by applying a ratio of the average BLS Producer Price Index for Electric Power from years 1993 and 2013. The Producer Price Index for Electric Power for 2016 is 201.4, and the Producer Price Index for Electric Power for 1993 is 128.6 (Reference 3). The 2016 dollars scaling factor is calculated as 201.4/128.6, which equals 1.57.

The replacement power costs PVRP was also adjusted to reflect the true need for replacement capacity availability based on current operations. A more realistic capacity factor of 95% is used in lieu of the suggested 60% - 65% range reported in NUREG/BR-0184 (Reference 2). This adjustment was applied as a simple multiplier derived by dividing 95% by 60% to get a value of 1.58.

PVRP = $2.56 x 109 * (1.57) * (1.58) = $6.35 x 109 To obtain the expected costs of a single event over the plant life, the following equation is used:

U RP = (FS FA )

PV RP r

( rt 1 e f )2 (11)

Where:

URP = net present value of replacement power over life of facility (dollars),

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

PVRP = net present value of replacement power for a single event ($),

r = real discount rate (7% per year),

tf = years remaining until end of plant life (60 years).

4-14 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Using the values given above, URP is calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.4.2.1 URP for At-Power Internal Events URP(IE) = (1.00x10-6 events per year - 0) x ($6.348x109) x (1 - e - (0.07 x 60))2

/ (0.07 per year)

= $87,986 4.4.2.2 URP for At-Power Internal Flooding Events URP (Fld) = (3.82x10-7 events per year - 0) x ($6.348x109) x (1 - e - (0.07 x 60))2

/ (0.07 per year)

= $33,611 4.4.2.3 URP for At-Power Internal Fire Events URP (Fire) = (2.79x10-6 events per year - 0) x ($6.348x109) x (1 - e - (0.07 x 60))2

/ (0.07 per year)

= $245,482 4.4.2.4 URP for LPSD Internal Events URP (SDIE) = (1.96x10-6 events per year - 0) x ($6.348x109) x (1 - e - (0.07 x 60))2

/ (0.07 per year)

= $170,693 4.4.2.5 URP for LPSD Flooding Events URP (SDFld) = (8.06x10-8 events per year - 0) x ($6.348x109) x (1 - e - (0.07 x 60))2

/ (0.07 per year)

= $7,092 4-15 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.4.2.6 URP for LPSD Fire Events URP (SDFire) = (1.48x10-6 events per year - 0) x ($6.348x109) x (1 - e - (0.07 x 60))2

/ (0.07 per year)

= $130,220 4.4.3 Averted Repair and Refurbishment Costs It is assumed that the plant would not be repaired or refurbished; therefore, these costs are zero.

4.4.4 Total Averted Onsite Costs (AOSC)

Total averted onsite cost is the sum of cleanup and decontamination costs, replacement power costs, and the repair and refurbishment costs. Total averted onsite costs are calculated as follows:

AOSC = UCD + URP + 0 (12)

Total averted onsite costs are calculated for at-power internal events, internal flooding events, and internal fire events, along with LPSD internal events, internal flooding events, and internal fire events. Each of these calculations is detailed below.

4.4.4.1 AOSC for At-Power Internal Events AOSC(IE) = $15,178 + $87,986 = $103,164 4.4.4.2 AOSC for At-Power Internal Flooding Events AOSC(Fld) = $5,798 + $33,611 = $39,409 4.4.4.3 AOSC for At-Power Internal Fire Events AOSC(Fire) = $42,348 + $245,482 = $287,830 4.4.4.4 AOSC for LPSD Internal Events AOSC(SDIE)= $29,446 + $170,693 = $200,139 4-16 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 4.4.4.5 AOSC for LPSD Flooding Events AOSC(SDFld)= $1,223 + $7,092 = $8,315 4.4.4.6 AOSC for LPSD Fire Events AOSC(SDFire)= $22,464 + $130,220 = $152,684 4.4.4.7 Total AOSC AOSCTot = AOSC(IE) + AOSC(Fld) + AOSC(Fire) + AOSC(SDIE) + AOSC(SDFld)

+ AOSC(SDFire)

= $103,164 + $39,409 + $287,830 + $200,139 + $8,315 + $152,684

= $791,541 4.5 Cost of Enhancement (COE)

The cost of enhancement is used when measures are taken to reduce risk. By definition, such measures are taken at the beginning of any period considered, therefore no discounting is performed for the COE. For baseline risk, no measures have been taken to reduce risk; therefore:

COE = $0 4.6 Total Unmitigated Baseline Risk As described in Section 4, the total present worth net value of public risk is calculated according to the following formula:

NPV = (APE + AOC + AOE + AOSC) - COE (13)

Using the values calculated in Sections 4.1 to 4.5, total baseline risk is calculated:

NPV = ($49,877 + $63,933 + $3,817 + $791,541) - $0 = $909,168 This value can be viewed as the maximum risk benefit attainable if all core damage scenarios are eliminated over the 60-years plant life.

4-17 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 5 IDENTIFICATION OF SAMDAS The list of SAMDA items evaluated for the APR1400 design is given in Table 5.

The first source used to identify SAMDA items is NEI 05-01 (Reference 1). Generic industry SAMDAs that were considered are the 153 items listed in Table 14 of NEI 05-01.

The second source used to identify SAMDA items is the result of PRA for APR1400 documented in DCD Chapter 19 (Reference 8). Evaluation of APR1400 specific items began with an importance analysis of the core damage cutsets documented in Reference 8.

The ASME PRA Standard (ASME/ANS RA-Sb-2009) defines a significant basic event as a basic event that contributes significantly to the computed risks for a specific hazard group.

This definition includes any basic event that has a FV importance greater than 0.005 (0.5%)

or a RAW importance greater than 2. The purpose of the SAMDA analysis is to consider ways to reduce risk. The RAW importance parameter does not provide indication of potential risk reduction and is not germane to a SAMDA analysis for risk reduction.

Therefore, the RAW importance measure is not used.

Each basic event with a Fussell-Vesely importance of greater than 0.5%, a total of 126 basic events for at-power internal events (Table 19.1-21 in Reference 8), 110 for at-power internal flooding events (Table 19.1-69 in Reference 8), 120 for at-power internal fire events (Table 19.1-52 in Reference 8), 79 for LPSD internal events (Table 19.1-100 in Reference 8), 75 for LPSD internal flooding events (Table 19.1-113 in Reference 8), and 98 for LPSD internal fire events (Table 19.1-126 in Reference 8), were reviewed to identify any potential SAMDAs. Basic events, such as complement events and constants, that have no physical meaning are identified and can be excluded as having no impact on the SAMDA analysis. A listing of the basic events, their importance, and their disposition with respect to SAMDA items is given in Tables 6a through 6f.

In addition to the basic event importance review, the top 100 cutsets for each analysis were reviewed to identify any basic events that were not included as part of the importance analysis review. Basic events identified in the top 100 cutsets that are not included as part of the importance analysis review are shown in Tables 7a through 7f. The top 100 cutsets for at-power internal events are taken from Table 19.1-19 in Reference 8. The top 100 cutsets for at-power internal flooding events are taken from Table 19.1-66 in Reference 8.

The top 100 cutsets for at-power internal fire events are taken from Table 19.1-49 in Reference 8. The top 100 cutsets for LPSD internal events are taken from Table 19.1-96 5-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification in Reference 8. The top 100 cutsets for LPSD internal flooding events are taken from Table 19.1-109 in Reference 8. The top 100 cutsets for LPSD internal fires events are taken from Table 19.1-122 in Reference 8.

5-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 6 SAMDA SCREENING The initial list of potential SAMDAs was developed from a generic list of sources related to many plant designs. Some of the items on the list were identified relatively recently, while others were identified some time ago. Given the wide diversity in age and sources of the potential SAMDAs, an initial screening is performed to identify the subset of potential SAMDAs that warranted a detailed evaluation.

Potential SAMDAs to be examined in detail are identified by exception. That is, a screening process is used to remove potential SAMDAs from consideration. Any potential SAMDAs not screened will undergo more detailed evaluation.

As described in Reference 1, SAMDA items can be screened for several reasons. First, items were screened that were not applicable to the APR1400. For example, some items are associated with specific equipment that is not present in the APR1400 design. Items screened as not applicable are indicated as Not Applicable in the Qualitative Screening column of Table 5.

Next, items were identified that were effectively implemented in the APR1400-DC design.

Items screened as effectively implemented are indicated with the letter Already Implemented in the Qualitative Screening column of Table 5. The reason for screening as Already Implemented is provided in Table 5.

Other SAMDA items were screened because they would not be feasible to implement. An item would not be feasible if the cost to implement the SAMDA clearly would exceed the maximum benefit possible (calculated in Section 4.6). Items screened as infeasible to implement are indicated with Excessive Imp. Cost in the Qualitative Screening column of Table 5.

Reference 1 allows items to be screened if they would be of low benefit. An item is of low benefit if it is from a non-risk-significant system and a change in reliability would have negligible impact on the risk profile. As this analysis is for the APR1400 design certification, any item listed as potentially being of low benefit are indicated as Needs Further Evaluation / Potentially Very Low Benefit in the Qualitative Screening column of Table 5. This assumption is based on engineering judgment and experience with other SAMDA analyses. The reason for screening as Very Low Benefit is provided in Table 5.

6-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Finally, one SAMDA can be Combined with others, per the guidelines of Reference 1.

SAMDA ID 151 is described as Increase training and operating experience feedback to improve operator response. As this analysis is for the APR1400 design certification, SAMDAs regarding operator actions are designated as N/A - Enhancement due to procedures/training are not applicable to the design certification stage of plant development. For this analysis, all other items not screened as above were retained in Table 5. The benefit and cost evaluations in the sections that follow then examine the impacts of the items. If appropriate, the items are combined during the benefit or cost evaluations. When items were combined as providing the same benefit, a note indicating which were analyzed together is provided in Table 5.

6-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7 SAMDA BENEFIT EVALUATION Each of the potential SAMDAs not screened was evaluated to determine the potential benefits that could be achieved if implemented. In evaluating the benefits, a precisely described modification was not necessarily considered because exact design details would only be defined once an option is chosen. Rather, SAMDA benefit evaluation was performed using bounding techniques to estimate any risk reduction that would be possible.

For example, evaluation of the SAMDA to install an additional component cooling water pump bounded the risk reduction possible by assuming that implementation of the SAMDA would entirely eliminate the unavailability of component cooling water pumps.

Evaluation of potential benefits would be performed using the methodology described in Reference 1 and, in general, would be performed as follows. First the potential reduction in CDF, if any, was estimated. Next, the reduction in source term release was estimated.

Finally, the potential benefit to offsite consequences was determined and presented in monetary terms.

Based on the information provided in Sections 4 and Tables 5, 6a through 6f, and 7a through 7f, the total maximum cost reduction calculated for any of the important basic events (FV > 0.5%) would be much lower than described in Tables 4, 6a through 6f, and 7a through 7f, because in reality, all offsite consequences would not be eliminated.

Therefore, a design change would be expected to cost more than this amount and, as a result, not provide a positive benefit.

The following sections describe the cost benefit of the important basic events and why no further SAMDA cost benefit evaluation is needed. The important basic events are grouped by the associated component to contribute to an overall maximum benefit. For components that can be considered identical, like EDGs or identical system pumps, a total of the components benefits are evaluated for overall maximum benefit.

7.1 Emergency Diesel Generator Events The generic SAMDA items evaluated for the APR1400 design related to emergency diesel generators are listed in Table 5 and include items 9, 19, 20, and 29.

7-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.1.1 EDG DG001A Events Basic events for the unavailability of EDG A are present in nearly all of the cutset file FV importance analyses and include: Table 6a (Items 14, 30, 56, 61, and 80), Table 6b (Items 70 and 96), Table 6c (Items 18, 36, 37, and 115), Table 6d (Items 14, 54, 67, and 73), Table 6e (Items 2, 17, 19, and 64), and Table 7d (Item 60). A maximum of 16% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG A unavailability in the At-Power internal events analysis, or approximately $16,400. A maximum of 1.7%

reduction in AOE and AOSC costs is possible by eliminating the effect of EDG A unavailability in the At-Power internal flooding events analysis, or approximately $670.

A maximum of 9.4% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG A unavailability in the At-Power fire events analysis, or approximately

$27,200.

A maximum of 7.6% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG A unavailability in the LPSD internal events analysis, or approximately

$15,200. A maximum of 42% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG A unavailability in the LPSD flooding events analysis, or approximately $3,500.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 or the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG, then an estimated maximum total benefit of approximately

$168,700 would occur.

The total maximum benefit would be much lower than $168,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an EDG would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.1.2 EDG DG001B Events Basic events for the unavailability of EDG B are present in all of the cutset file FV importance analyses and include: Table 6a (Items 15, 35, 56, 62, and 86), Table 6b (Items 63 and 78), Table 6c (Items 15, 32, 36, and 106), Table 6d (Items 15, 55, 68, and 73), Table 7-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 6e (Items 26 and 64), Table 6f (Item 57), Table 7d (Item 60). A maximum of 15%

reduction in AOE and AOSC costs is possible by eliminating the effect of EDG B unavailability in the At-Power internal events analysis, or approximately $15,000. A maximum of 1.7% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG B unavailability in the At-Power internal flooding events analysis, or approximately $8600. A maximum of 9.4% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG B unavailability in the At-Power fire events analysis, or approximately $30,400.

A maximum of 7.6% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG B unavailability in the LPSD internal events analysis, or approximately

$15,200. A maximum of 2.9% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG B unavailability in the LPSD flooding events analysis, or approximately $240. A maximum of 1.4% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG B unavailability in the LPSD fire events analysis, or approximately $2,100.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($49,877) and AOC ($63,933), total only $113,810 or the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG, then an estimated maximum total benefit of approximately

$177,700 would occur.

The total maximum benefit would be much lower than $177,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an EDG would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.1.3 EDG DG001C Events Basic events for the unavailability of EDG C are present in all of the cutset file FV importance analyses except LPSD internal fire events and include: Table 6a (Items 31, 37, 56, 105, and 124), Table 6b (Items 45 and 66), Table 6c (Items 37, 51, and 93), Table 6d (Item 73), and Table 6e (Item 64). A maximum of 9.8% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG C unavailability in the At-Power internal 7-3 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification events analysis, or approximately $10,200. A maximum of 3.8% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG C unavailability in the At-Power internal flooding events analysis, or approximately $1,500. A maximum of 4.7%

reduction in AOE and AOSC costs is possible by eliminating the effect of EDG C unavailability in the At-Power fire events analysis, or approximately $13,600.

A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG C unavailability in the LPSD internal events analysis, or approximately

$1,100. A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG C unavailability in the LPSD flooding events analysis, or approximately $40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 or the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG, then an estimated maximum total benefit of approximately

$132,000 would occur.

The total maximum benefit would be much lower than $132,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an EDG would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.1.4 EDG DG001D Events Basic events for the unavailability of EDG D are present in all of the cutset file FV importance analyses except LPSD internal fire events and include: Table 6a (Items 32, 43, 56, and 110), Table 6b (Items 43 and 59), Table 6c (Items 35, 42, and 74), Table 6d (Item 73), Table 6e (Items 8, 34, 43, and 64). A maximum of 8.9% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG D unavailability in the At-Power internal events analysis, or approximately $9,200. A maximum of 4.0% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG D unavailability in the At-Power internal flooding events analysis, or approximately $1,600. A maximum of 5.2%

reduction in AOE and AOSC costs is possible by eliminating the effect of EDG D unavailability in the At-Power fire events analysis, or approximately $15,100.

7-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG D unavailability in the LPSD internal events analysis, or approximately

$1,100. A maximum of 12.5% reduction in AOE and AOSC costs is possible by eliminating the effect of EDG D unavailability in the LPSD flooding events analysis, or approximately $1,100.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 or the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG, then an estimated maximum total benefit of approximately

$133,600 would occur.

The total maximum benefit would be much lower than $133,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an EDG would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.1.5 Load Sequencer Events Basic events for the unavailability of diesel generator load sequencer are present in the At-Power internal events and At-Power internal events, At-Power internal fire and LPSD internal events, LPSD internal flood cutset file FV importance analysis and include: Table 6a (Items 68, 72, 116, and 120), Table 6c (Item 113), Table 6d (Items 63 and 64), Table 6e (Items 18 and 36). And Table 7c (Items 1 and 11). A maximum of 3.8% reduction in AOE and AOSC costs is possible by eliminating the effect of load sequencer unavailability in the At-Power internal events analysis, or approximately $4,000. A maximum of 1.5%

reduction in AOE and AOSC costs is possible by eliminating the effect of load sequencer unavailability in the At-Power fire events analysis, or approximately $4,300.

A maximum of 1.4% reduction in AOE and AOSC costs is possible by eliminating the effect of load sequencer unavailability in the LPSD internal events analysis, or approximately $2,800. A maximum of 5.6% reduction in AOE and AOSC costs is possible by eliminating the effect of load sequencer unavailability in the LPSD flooding events analysis, or approximately $470.

7-5 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($44,639) and AOC ($57,495), total only $102,134 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the load sequencer, then an estimated maximum total benefit of approximately $34,600 would occur.

The total maximum benefit would be much lower than $34,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of a load sequencer would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.1.6 Total EDG Event Summary Evaluating all four EDGs above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all EDG unavailability is approximately $181,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE and AOC, total only $113,800. Therefore, an estimated maximum total benefit of approximately $295,000 is achievable.

The total maximum benefit would be much lower than $295,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an EDG would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.2 AAC Combustion Turbine Generator Events The generic SAMDA items evaluated for the APR1400 design related to CTG are listed in Table 5 and include item 15.

7.2.1 AAC CTG Events Basic events for the unavailability of the AAC CTG are present in all of the cutset file FV importance analyses for At-Power internal events, At-Power internal fire, LPSD flooding events and include: Table 6a (Items 20 and 59), Table 6c (Items 13 and 57), and Table 6d 7-6 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification (Items 38 and 66). A maximum of 7.5% reduction in AOE and AOSC costs is possible by eliminating the effect of AAC CTG unavailability in the At-Power internal events analysis, or approximately $7,800. A maximum of 6.4% reduction in AOE and AOSC costs is possible by eliminating the effect of AAC CTG unavailability in the At-Power fire events analysis, or approximately $18,600.

A maximum of 2.7% reduction in AOE and AOSC costs is possible by eliminating the effect of the AAC CTG unavailability in the LPSD internal events analysis, or approximately $5,500.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($40,693) and AOC ($53,072), total only $93,765 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the AAC CTG, then an estimated maximum total benefit of approximately $125,600 would occur.

The total maximum benefit would be much lower than $193,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the AAC CTG would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.3 Auxiliary Feedwater Events The generic SAMDA items evaluated for the APR1400 design related to auxiliary feedwater are listed in Table 5 and include items 66, 67, 71, 75, 77, and 78.

7.3.1 AFW Isolation Valve MOV-45 Events Basic events for the unavailability of AFW isolation valve MOV-45 are present in the At-Power internal events, At-Power internal fire, and At-Power internal flooding cutset file FV importance analyses and include: Table 6a (Items 24 and 25), Table 6b (Items 9 and 10),

and Table 6c (Items 10 and 11). A maximum of 10.3% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-45 unavailability in the At-Power internal events analysis, or approximately $10,600. A maximum of 19.2% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-45 unavailability in the At-Power internal flooding events analysis, or approximately $7,600. A maximum of 10.2%

7-7 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-45 unavailability in the At-Power fire events analysis, or approximately $29,600.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the AFW MOV, then an estimated maximum total benefit of approximately $123,400 would occur.

The total maximum benefit would be much lower than $123,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of MOV-45 would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.3.2 AFW Isolation Valve MOV-46 Events Basic events for the unavailability of AFW isolation valve MOV-46 are present in the At-Power internal events, At-Power internal flooding events, and At-Power internal events cutset file FV importance analyses and include: Table 6a (Items 22 and 23), Table 6b (Items 12 and 13), and Table 6c (Items 26 and 27). A maximum of 10.6% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-46 unavailability in the At-Power internal events analysis, or approximately $11,100. A maximum of 17.2%

reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-46 unavailability in the At-Power internal flooding events analysis, or approximately $6,800.

A maximum of 16.1% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-46 unavailability in the At-Power fire events analysis, or approximately

$17,600.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the AFW MOV, then an estimated maximum total benefit of approximately $111,000 would occur.

The total maximum benefit would be much lower than $111,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-8 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of MOV-46 would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.3.3 AFW Turbine Driven Pump PP01A Events Basic events for the unavailability of AFW turbine driven pump PP01A are present in At-Power cutset file FV importance analyses and include: Table 6a (Items 8, 10, 55, 58, 67, and 83), Table 6b (Items 18, 72, 75, 83, and 86), Table 6c (Items 17, 69, 100, and 109), and Table 7a (Item 12). A maximum of 26.8% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW TDP A unavailability in the At-Power internal events analysis, or approximately $27,800. A maximum of 9.3% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW TDP A unavailability in the At-Power internal flooding events analysis, or approximately $3,700. A maximum of 6.8%

reduction in AOE and AOSC costs is possible by eliminating the effect of AFW TDP A unavailability in the At-Power fire events analysis, or approximately $19,500.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the TDAFP, then an estimated maximum total benefit of approximately

$126,500 would occur.

The total maximum benefit would be much lower than $126,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the TDAFP would affect only induced SGTR events.

7.3.4 AFW Turbine Driven Pump PP01B Events Basic events for the unavailability of AFW turbine driven pump PP01B are present in the At-Power cutset file FV importance analyses and include: Table 6a (Items 10, 11, 55, 66, 81, 93), Table 6b (Items 20, 73, 79, 83, and 97), Table 6c (Items 31 and 69), and Table 7a (Item 12). A maximum of 24.5% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW TDP B unavailability in the At-Power internal events analysis, or approximately $25,400. A maximum of 8.6% reduction in AOE and AOSC 7-9 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification costs is possible by eliminating the effect of AFW TDP B unavailability in the At-Power internal flooding events analysis, or approximately $3,400. A maximum of 3.9%

reduction in AOE and AOSC costs is possible by eliminating the effect of AFW TDP B unavailability in the At-Power fire events analysis, or approximately $11,400.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the TDAFP, then an estimated maximum total benefit of approximately

$115,700 would occur.

The total maximum benefit would be much lower than $115,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the TDAFP would affect only induced SGTR events.

7.3.5 AFW Motor Driven Pump PP02A Events Basic events for the unavailability of AFW motor driven pump PP02A are present in n in the At-Power cutset file FV importance analyses and include: Table 6a (Items 10 and 57),

Table 6b (Item 30 and 83), Table 6c (Items 19 and 69), Table 7a (Item 12). A maximum of 12.2% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW MDP A unavailability in the At-Power internal events analysis, or approximately $12,600.

A maximum of 4.5% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW MDP A unavailability in the At-Power internal flooding events analysis, or approximately $1,800. A maximum of 5.3% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW MDP A unavailability in the At-Power fire events analysis, or approximately $15,400.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the MDAFP, then an estimated maximum total benefit of approximately

$105,400 would occur.

The total maximum benefit would be much lower than $105,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-10 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MDAFP would affect only induced SGTR events.

7.3.6 AFW Motor Driven Pump PP02B Events Basic events for the unavailability of AFW motor driven pump PP02B are present in the At-Power cutset file FV importance analyses and include: Table 6a (Item 10 and 99),

Table 6b (Items 37 and 83), and Table 6c (Items 43 and 69), and Table 7a (Item 12). A maximum of 11.2% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW MDP B unavailability in the At-Power internal flooding events analysis, or approximately $11,600. A maximum of 3.9% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW MDP B unavailability in the At-Power internal flooding events analysis, or approximately $1,600. A maximum of 3.0% reduction in AOE and AOSC costs is possible by eliminating the effect of AFW MDP B unavailability in the At-Power fire events analysis, or approximately $8,700.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the MDAFP, then an estimated maximum total benefit of approximately

$97,300 would occur.

The total maximum benefit would be much lower than $97,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MDAFP would affect only induced SGTR events.

7.3.7 Startup FW Pump PP07 Events Basic events for the unavailability of startup FW pump PP07 are present in only the At-Power internal events cutset file FV importance analysis and include: Table 6a (Item 73).

A maximum of 1.3% reduction in AOE and AOSC costs is possible by eliminating the effect of startup FW pump PP07 unavailability in the At-Power internal events analysis, or approximately $1,300.

7-11 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the MDAFP, then an estimated maximum total benefit of approximately

$37,900 would occur.

The total maximum benefit would be much lower than $37,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the startup FW pump would affect only induced SGTR events.

7.3.8 Total AFW Isolation Valve Event Summary Evaluating all AFW isolation valve events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all AFW isolation valve unavailability is approximately $83,400. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642) for the hazards affected. If all offsite consequences were abated by eliminating any risk contribution from the AFW MOVs, then an estimated maximum total benefit of approximately $158,900 would occur.

The total maximum benefit would be much lower than $158,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 3a through 3f. Improved performance of the AFW MOVs would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.3.9 Total AFW Turbine Driven Pump Event Summary Evaluating all AFW turbine driven pump events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all AFW turbine driven pump unavailability is approximately $91,300. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642) for the hazards affected. If all offsite consequences were abated by eliminating any risk contribution from the TDAFPs, then an estimated maximum total benefit of approximately

$166,800 would occur.

7-12 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $166,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the TDAFPs would affect only induced SGTR events.

7.3.10 Total AFW Motor Driven Pump Event Summary Evaluating all AFW motor driven pump events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all AFW motor driven pump unavailability is approximately $51,700. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642) for the hazards affected. Therefore, an estimated maximum total benefit of approximately

$127,100 is achievable.

The total maximum benefit would be much lower than $127,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MDAFP would affect only induced SGTR events.

7.4 Fire Barrier Failure Events The generic SAMDA items evaluated for the APR1400 design related to barrier failure are listed in Table 5 and includes item 143.

7.4.1 Fire Barrier Unavailability Basic events for the unavailability of fire barriers are present in the At-Power and LPSD fire event cutset file FV importance analyses and include: Table 6c (Items 41, 83, and 119), Table 6f (Item 87), Table 7c (Items 7, 19, and 21), and Table 7f (Items 1, 2, 7, 8, 15, and 20). A maximum of 3.7% reduction in AOE and AOSC costs is possible by eliminating the effect of all barrier unavailability in the At-Power fire events analysis, or approximately $10,700. A maximum of 2.5% reduction in AOE and AOSC costs is possible by eliminating the effect of all barrier unavailability in the LPSD fire events analysis, or approximately $3,800.

7-13 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($19,981) and AOC ($23,516), total only $43,497 for all fire events. If all offsite consequences were abated by eliminating any offsite risk contribution from failure of fire barriers, then an estimated maximum total benefit of approximately $58,000 would occur.

The total maximum benefit would be much lower than $58,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the fire barrier would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.5 Component Cooling Water (CCW) Events The generic SAMDA items evaluated for the APR1400 design related to CCW are listed in Table 5 and includes item 59.

7.5.1 CCW Pump PP02A Events Basic events for the unavailability of CCW pump PP02A are present in the At-Power internal events, At-Power internal flooding, and At-Power internal fire cutset file FV importance analysis and include: Table 6a (Item 102), Table 6b (Item 58), and Table 7c (Item 23). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump A unavailability in the At-Power internal flooding events analysis, or approximately $730. A maximum of 1.5% reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump A unavailability in the At-Power internal flooding events analysis, or approximately $590. A maximum of 0.2%

reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump A unavailability in the At-Power fire events analysis, or approximately $520.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CCW pump, then an estimated maximum total benefit of approximately $77,300 would occur.

The total maximum benefit would be much lower than $77,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-14 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.5.2 CCW Pump PP02B Events Basic events for the unavailability of CCW pump PP02B are present in the At-Power internal events, At-Power internal flooding, At-Power internal fire, and LPSD internal flood cutset file FV importance analyses and include: Table 6a (Item 109), Table 6b (Item 62),

and Table 6e (Item 66), and Table 7c (Item 23). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump B unavailability in the At-Power internal flooding events analysis, or approximately $670. A maximum of 1.4%

reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump B unavailability in the At-Power internal flooding events analysis, or approximately $570.

A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump B unavailability in the At-Power fire events analysis, or approximately $520.

A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of CCW pump B unavailability in the LPSD internal flooding events analysis, or approximately $40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($36,791) and AOC ($47,065), total only $83,856 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CCW pump, then an estimated maximum total benefit of approximately $85,700 would occur.

The total maximum benefit would be much lower than $85,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7-15 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.5.3 CS Heat Exchanger HE01A CCW Inlet Valve MOV-97 Basic events for the unavailability of CS heat exchanger HE01A CCW inlet valve MOV-97 are present only in the At-Power internal events cutset file FV importance analysis and include: Table 6a (Item 97) and Table 7a (Item 22). A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CS heat exchanger HE01A CCW inlet valve MOV-97 unavailability in the At-Power internal events analysis, or approximately $1,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the valve, then an estimated maximum total benefit of approximately

$37,800 would occur.

The total maximum benefit would be much lower than $37,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW valve would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.5.4 CS Heat Exchanger HE01B CCW Inlet Valve MOV-98 Basic events for the unavailability of CS heat exchanger HE01B CCW inlet valve MOV-98 are present in only the At-Power internal events cutset file FV importance analyses and include: Table 6a (Item 97) and Table 7a (Item 22). A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CS heat exchanger HE01A CCW inlet valve MOV-97 unavailability in the At-Power internal events analysis, or approximately $1,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the valve, then an estimated maximum total benefit of approximately

$37,800 would occur.

7-16 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $37,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW valve would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.5.5 DG001A CCW Inlet Valve MOV-191 Basic events for the unavailability of DG001A CCW inlet valve MOV-191 are present in only the LPSD internal flooding cutset file FV importance analyses and include: Table 6e (Item 37). A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-191 unavailability in the LPSD internal flooding analysis, or approximately $100.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($3,946) and AOC ($4,423), total only $8,369 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the valve, then an estimated maximum total benefit of approximately $8,500 would occur.

The total maximum benefit would be much lower than $8,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW valve would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.5.6 Total CCW Pump Event Summary Evaluating all CCW pump events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all CCW pump unavailability is approximately $3,600. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($36,791) and AOC ($47,065), total only $83,856 for the hazards impacted. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CCW pump, then an estimated maximum total benefit of approximately $87,500 would occur.

7-17 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $87,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.5.7 Total CS Heat Exchanger CCW Inlet Valve Event Summary Evaluating all CS heat exchanger CCW inlet valve events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all CCW pump unavailability is approximately $2,400. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only

$36,580 for the impacted hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CCW pump, then an estimated maximum total benefit of approximately $40,000 would occur.

The total maximum benefit would be much lower than $40,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CCW valves would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6 Containment Spray (CS) Events 7.6.1 Containment Spray Pump PP01A Events Basic events for the unavailability of containment spray pump PP01A are present in the At-Power internal events, At-Power internal flooding, and LPSD internal events cutset file FV importance analyses and include: Table 6a (Item 71), Table 6b (Item 92), Table 6d (Item 72), Table 7a (Item 10), Table 7d (Items 28 and 30). A maximum of 1.6% reduction in AOE and AOSC costs is possible by eliminating the effect of CS pump A unavailability in the At-Power internal events analysis, or approximately $1,600. A maximum of 0.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of CS pump A unavailability in the At-Power internal flooding events analysis, or approximately $250.

A maximum of 0.8% reduction in AOE and AOSC costs is possible by eliminating the 7-18 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification effect of CS pump A unavailability in the LPSD internal events analysis, or approximately

$1,700.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($25,950) and AOC ($35,994), total only $61,944 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CCW pump, then an estimated maximum total benefit of approximately $65,400 would occur.

The total maximum benefit would be much lower than $65,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CS pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.2 Containment Spray Pump PP01B Events Basic events for the unavailability of containment spray pump PP01B are present in the At-Power internal events and LPSD internal events cutset file FV importance analyses and include: Table 6a (Item 65), Table 6d (Item 72), Table 7a (Item 10), and Table 7d (Items 28 and 30). A maximum of 1.7% reduction in AOE and AOSC costs is possible by eliminating the effect of CS pump B unavailability in the At-Power internal events analysis, or approximately $1,700. A maximum of 0.8% reduction in AOE and AOSC costs is possible by eliminating the effect of CS pump B unavailability in the LPSD internal events analysis, or approximately $1,700.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($24,399) and AOC ($34,002), total only $58,401 for the hazards affected. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CCW pump, then an estimated maximum total benefit of approximately $361,800 would occur.

The total maximum benefit would be much lower than $361,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved 7-19 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification performance of the CS pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.3 Containment Spray Isolation Valve MOV-003 Events Basic events for the unavailability of containment spray isolation valve MOV-003 are present in only the At-Power internal events cutset file FV importance analysis and include:

Table 6a (Item 111). A maximum of 0.6% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-003 unavailability in the At-Power internal events analysis, or approximately $660.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the CS valve, then an estimated maximum total benefit of approximately $37,200 would occur.

The total maximum benefit would be much lower than $35,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CS valves would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.4 Containment Spray Isolation Valve MOV-004 Events Basic events for the unavailability of containment spray isolation valve MOV-004 are present in only the At-Power internal events cutset file FV importance analysis and include:

Table 6a (Item 111) and Table 7a (Item 24). A maximum of 1.0% reduction in AOE and AOSC costs is possible by eliminating the effect of MOV-004 unavailability in the At-Power internal events analysis, or approximately $1,100.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the CS valve, then an estimated maximum total benefit of approximately $37,700 would occur.

The total maximum benefit would be much lower than $37,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-20 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 3a through 4f. Improved performance of the CS valves would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.5 Containment Spray Heat Exchanger HE-01B Events Basic events for the unavailability of containment spray heat exchanger HE-01B are present in only the At-Power internal events cutset file FV importance analysis and include:

Table 6a (Item 82). A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of HE-01B unavailability in the At-Power internal events analysis, or approximately $1,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the CS heat exchanger, then an estimated maximum total benefit of approximately $37,800 would occur.

The total maximum benefit would be much lower than $37,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CS valves would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.6 Containment Spray Heat Exchanger HE-01A Events Basic events for the unavailability of containment spray heat exchanger HE-01A are present in only the At-Power internal events cutset file FV importance analysis and include:

Table 6a (Item 84). A maximum of 1.12% reduction in AOE and AOSC costs is possible by eliminating the effect of HE-01A unavailability in the At-Power internal events analysis, or approximately $1,500.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the CS heat exchanger, then an estimated maximum total benefit of approximately $37,800 would occur.

7-21 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $37,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CS valves would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.7 Total Containment Spray Pump Event Summary Evaluating all CS pump events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all CS pump unavailability is approximately

$6,900. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($25,950) and AOC ($35,994), total only $61,944 for the hazards impacted. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the CS pumps, then an estimated maximum total benefit of approximately $68,900 would occur.

The total maximum benefit would be much lower than $68,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CS pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.8 Total Containment Spray Isolation Valve Event Summary Evaluating both CS isolation valve events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all CS isolation valve unavailability is approximately $1,700. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the CS valves, then an estimated maximum total benefit of approximately $38,300 would occur.

The total maximum benefit would be much lower than $38,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved 7-22 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification performance of the CS valves would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.6.9 Total Containment Spray Heat Exchanger Event Summary Evaluating both CS heat exchanger events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all CS heat exchanger unavailability is approximately $2,300. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the CS heat exchangers, then an estimated maximum total benefit of approximately $38,900 would occur.

The total maximum benefit would be much lower than $39,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the CS heat exchangers would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.7 125 VDC Power Events The generic SAMDA items evaluated for the APR1400 design related to DC power are listed in Table 4 and include items 1, 2, 3, 5, and 74.

7.7.1 125 VDC Power Battery BT01A Events Basic events for the unavailability of 125 VDC battery BT01A are present in the At-Power internal events, At-Power internal flooding, and At-Power internal fire cutset file FV importance analyses and include: Table 6a (Item 21), Table 6b (Item 55), and Table 6c (Item 61). A maximum of 5.4% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01A unavailability in the At-Power internal events analysis, or approximately $6,200. A maximum of 1.7% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01A unavailability in the At-Power internal flooding events analysis, or approximately $680. A maximum of 1.4% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01A unavailability in the At-Power internal fire analysis, or approximately $4,000.

7-23 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the battery, then an estimated maximum total benefit of approximately

$85,800 would occur.

The total maximum benefit would be much lower than $85,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the battery would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.7.2 125 VDC Power Battery BT01B Events Basic events for the unavailability of 125 VDC battery BT01B are present in the At-Power internal events, At-Power internal flooding, and At-Power internal fire cutset file FV importance analyses and include: Table 6a (Item 17), Table 6b (Item 56), and Table 6c (Item 39). A maximum of 6.0% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01B unavailability in the At-Power internal events analysis, or approximately $6,200. A maximum of 1.7% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01B unavailability in the At-Power internal flooding events analysis, or approximately $680. A maximum of 1.4% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01B unavailability in the At-Power internal fire events analysis, or approximately $4,000.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the battery, then an estimated maximum total benefit of approximately

$85,400 would occur.

The total maximum benefit would be much lower than $85,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved 7-24 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification performance of the battery would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.7.3 125 VDC Power Battery BT01C Events Basic events for the unavailability of 125 VDC battery BT01C are present in only the At-Power internal events cutset file FV importance analyses and include: Table 6a (Item 74).

A maximum of 1% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01C unavailability in the At-Power internal events analysis, or approximately

$1,300.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the battery, then an estimated maximum total benefit of approximately $37,900 would occur.

The total maximum benefit would be much lower than $37,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the battery would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.7.4 125 VDC Power Battery BT01D Events Basic events for the unavailability of 125 VDC battery BT01D are present in only the At-Power internal events cutset file FV importance analyses and include: Table 6a (Item 74).

A maximum of 1% reduction in AOE and AOSC costs is possible by eliminating the effect of battery BT01D unavailability in the At-Power internal events analysis, or approximately

$1,300.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events. If all offsite consequences were abated by eliminating any risk contribution from the battery, then an estimated maximum total benefit of approximately $37,900 would occur.

The total maximum benefit would be much lower than $37,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-25 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the battery would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.7.5 Total 125 VDC Power Battery Event Summary Evaluating all 125 VDC power battery events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all battery unavailability is approximately $10,300. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the batteries, then an estimated maximum total benefit of approximately $101,200 would occur.

The total maximum benefit would be much lower than $101,200 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the battery would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.8 120 VAC Power Events The generic SAMDA items evaluated for the APR1400 design related to 120V AC power are listed in Table 5 and include items 6, 7, and 16).

7.8.1 120V Inverter IN01A Basic events for the unavailability of 120V inverter IN01A are present in the At-Power internal events, At-Power internal flooding events, and At-Power internal fire cutset file FV importance analyses and include: Table 6a (Item 36), Table 6b (Item 76), Table 6c (Item 110). A maximum of 3.1% reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01A unavailability in the At-Power internal events analysis, or approximately $3,200. A maximum of 0.8% reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01A unavailability in the At-Power internal flooding events analysis, or approximately $320. A maximum of 0.6% reduction in AOE 7-26 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification and AOSC costs is possible by eliminating the effect of inverter IN01A unavailability in the At-Power internal fire analysis, or approximately $1,700.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the inverter, then an estimated maximum total benefit of approximately

$80,700 would occur.

The total maximum benefit would be much lower than $80,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the inverter would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.8.2 120V Inverter IN01B Basic events for the unavailability of 120V inverter IN01B are present in the At-Power internal events, At-Power internal flooding events, and At-Power internal fire events cutset file FV importance analyses and include: Table 6a (Item 33), Table 6b (Item 81), Table 6c (Item 107). A maximum of 3.5% reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01B unavailability in the At-Power internal events analysis, or approximately $3,600. A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01B unavailability in the At-Power internal flooding events analysis, or approximately $1,600. A maximum of 0.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01B unavailability in the At-Power internal fire analysis, or approximately $1,700.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the inverter, then an estimated maximum total benefit of approximately

$80,700 would occur.

The total maximum benefit would be much lower than $95,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events 7-27 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the inverter would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.8.3 120V Inverter IN01C Basic events for the unavailability of 120V inverter IN01C are present in the At-Power internal events cutset file FV importance analyses and include: Table 6a (Item 98). A maximum of 0.8% reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01C unavailability in the At-Power internal events analysis, or approximately

$780.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events, at-power internal flooding, and LPSD fire events. If all offsite consequences were abated by eliminating any risk contribution from the inverter, then an estimated maximum total benefit of approximately $37,400 would occur.

The total maximum benefit would be much lower than $37,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the inverter would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.8.4 120V Inverter IN01D Basic events for the unavailability of 120V inverter IN01D are present in the At-Power internal events and LPSD fire events cutset file FV importance analyses and include:

Table 6a (Item 101). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of inverter IN01D unavailability in the At-Power internal events analysis, or approximately $750.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for at-power internal events, at-power internal flooding, and LPSD fire events. If all offsite consequences were abated by eliminating any risk contribution from the inverter, then an estimated maximum total benefit of approximately $37,400 would occur.

7-28 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $37,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the inverter would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.8.5 Total 120V inverter Event Summary Evaluating all 120V inverter events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all 120V inverter unavailability is approximately $12,500. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the inverter, then an estimated maximum total benefit of approximately $88,000 would occur.

The total maximum benefit would be much lower than $106,900 because all offsite consequences would not be eliminated. As can be seen from Tables 2a through 2f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 3a through 3f. Improved performance of the inverter would have a negligible effect on reducing risk from SGTR and ISLOCA events. Therefore, a design change to improve performance of the inverters would have a negligible benefit.

7.9 AC Power Events The generic SAMDA items evaluated for the APR1400 design related to AC power are listed in Table 5 and include item 16.

7.9.1 SAT Transformer 2M Events Basic events for the unavailability of SAT transformer 2M are present in the At-Power internal flooding events and At-Power internal fire cutset file FV importance analysis and include: Table 6b (Item 61), and Table 6c (Item 50). A maximum of 1.5% reduction in AOE and AOSC costs is possible by eliminating the effect of SAT transformer 2M in the At-Power internal flooding events analysis, or approximately $570. A maximum of 1.6%

7-29 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification reduction in AOE and AOSC costs is possible by eliminating the effect of SAT transformer 2M in the At-Power internal fire events analysis, or approximately $4,700.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($17,845) and AOC ($21,062), total only $38,907 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the transformer, then an estimated maximum total benefit of approximately $44,200 would occur.

The total maximum benefit would be much lower than $44,200 because all offsite consequences would not be eliminated. As can be seen from Tables 2a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the transformer would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.2 SAT Transformer 2N Events Basic events for the unavailability of SAT transformer 2N are present in the At-Power internal flooding events and At-Power internal fire events cutset files FV importance analysis and include: Table 6b (Item 64) and Table 6c (Item 20). A maximum of 1.4%

reduction in AOE and AOSC costs is possible by eliminating the effect of SAT transformer 2N in the At-Power internal flooding events analysis, or approximately $540. A maximum of 3.5% reduction in AOE and AOSC costs is possible by eliminating the effect of SAT transformer 2M in the At-Power internal fire events analysis, or approximately

$10,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($17,845) and AOC ($21,062), total only $38,907 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the transformer, then an estimated maximum total benefit of approximately $49,700 would occur.

The total maximum benefit would be much lower than $49,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved 7-30 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification performance of the transformer would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.3 PCB SW01A-A2 To 4.16KV Switchgear SW01A Events Basic events for the unavailability of PCB SW01A-A2 To 4.16KV Switchgear SW01A are present in only the At-Power internal flooding and At-Power internal fire events cutset file FV importance analyses and include: Table 6b (Item 57) and Table 6c (Item 55). A maximum of 1.5% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-A2 in the At-Power internal flooding events analysis, or approximately

$540. A maximum of 1.5% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-A2 in the At-Power internal flooding events analysis, or approximately $4,300.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($17,845) and AOC ($21,062), total only $38,907 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $43,800 would occur.

The total maximum benefit would be much lower than $43,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.4 PCB SW01B-A2 To 4.16KV Switchgear SW01B Events Basic events for the unavailability of PCB SW01B-A2 To 4.16KV Switchgear SW01B are present in the At-Power internal flooding events, At-Power internal fire, and LPSD internal events cutset file FV importance analysis and include: Table 6b (Item 65), Table 6c (Item 70), and Table 7d (Item 35). A maximum of 1.4% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01B-A2 in the At-Power internal flooding events analysis, or approximately $540. A maximum of 1.5% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01B-A2 in the At-Power internal flooding events analysis, or approximately $3,300. A maximum of 0.4%

7-31 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01B-A2 in the LPSD internal events analysis, or approximately $720.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($27,244) and AOC ($33,484), total only $60,728 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $65,300 would occur.

The total maximum benefit would be much lower than $65,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.5 PCB SW01C-A2 To 4.16KV Switchgear SW01C Events Basic events for the unavailability of PCB SW01C-A2 To 4.16KV Switchgear SW01A are present in only the At-Power and LPSD internal flooding events cutset file FV importance analyses and include: Table 6b (Item 99). A maximum of 0.6% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01C-A2 in the At-Power internal flooding events analysis, or approximately $230.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($1,551) and AOC ($1,992), total only $3,543 for internal flooding events. If all offsite consequences were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $3,800 would occur.

The total maximum benefit would be much lower than $3,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7-32 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.9.6 PCB SW01A-H2 To 4.16KV Switchgear SW01A From UAT Events Basic events for the unavailability of PCB SW01A-H2 To 4.16KV Switchgear SW01A from the UAT are present in the At-Power internal events, At-Power internal flooding, LPSD internal events, and LPSD internal flooding cutset file FV importance analyses and include: Table 6a (Items 40 and 103), Table 6b (Items 2, 8, 34, 35, 54, 58, 71, and 109),

Table 6e (Items 9 and 73), and Table 7d (Items 25 and 41). A maximum of 3.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-H2 in the At-Power internal events analysis, or approximately $3,800. A maximum of 41%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-H2 in the At-Power internal flooding events analysis, or approximately $16,300. A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-H2 in LPSD internal events analysis, or approximately $1,300. A maximum of 9.2% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-H2 in LPSD internal flooding analysis, or approximately $770.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($29,896) and AOC ($40,417), total only $70,313 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $92,600 would occur.

The total maximum benefit would be much lower than $92,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.7 PCB SW01B-H2 To 4.16KV Switchgear SW01B From UAT Events Basic events for the unavailability of PCB SW01B-H2 To 4.16KV Switchgear SW01B from the UAT are present in only the At-Power internal events, At-Power internal flood, LPSD internal events, and LPSD internal flood cutset file FV importance analyses and include: Table 6a (Items 42 and 103), Table 6b (Items 5, 8, 35, 38, 41, 54, 71, and 110),

Table 6e (Items 61 and 73), and Table 7d (Items 25 and 41). A maximum of 3.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01B-H2 7-33 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification in the At-Power internal events analysis, or approximately $3,700. A maximum of 41%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01B-H2 in the At-Power internal flooding events analysis, or approximately $16,300. A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01B-H2 in LPSD internal events analysis, or approximately $1,300. A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01A-H2 in LPSD internal flooding analysis, or approximately $90.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($29,896) and AOC ($40,417), total only $70,313 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $91,800 would occur.

The total maximum benefit would be much lower than $91,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.8 PCB SW01C-C2 To 4.16KV Switchgear SW01C From UAT Events Basic events for the unavailability of PCB SW01C-C2 To 4.16KV Switchgear SW01C from the UAT are present in only the At-Power internal events, At-Power internal flood, LPSD internal events, and LPSD internal flood cutset file FV importance analyses and include: Table 6a (Items 77 and 103), Table 6b (Items 8, 23, 34, 35, 38, 54, and 110),

Table 6e (Item 73), and Table 7d (Items 25 and 41). A maximum of 1.9% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01C-C2 in the At-Power internal events analysis, or approximately $2,000. A maximum of 29% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01C-C2 in the At-Power internal flooding events analysis, or approximately $11,300. A maximum of 0.7%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01C-C2 in LPSD internal events analysis, or approximately $1,300. A maximum of 0.5%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01C-C2 in LPSD internal flooding analysis, or approximately $40.

7-34 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($29,896) and AOC ($40,417), total only $70,313 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $85,000 would occur.

The total maximum benefit would be much lower than $85,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.9 PCB SW01D-G2 To 4.16KV Switchgear SW01D From UAT Events Basic events for the unavailability of PCB SW01D-G2 To 4.16KV Switchgear SW01D from the UAT are present in the At-Power internal events, At-Power internal flooding, LPSD internal events, and LPSD internal flood cutset file FV importance analyses and include: Table 6a (Items 78 and 103), Table 6b (Items 8, 31, 35, 38, 41, 71, and 109),

Table 6e (Items 25 and 73), and Table 7d (Items 25 and 41). A maximum of 1.9%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01D-G2 in the At-Power internal events analysis, or approximately $2,000. A maximum of 26%

reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01D-G2 in the At-Power internal flooding events analysis, or approximately $10,200. A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01D-G2 in LPSD internal events analysis, or approximately $1,300. A maximum of 3.0% reduction in AOE and AOSC costs is possible by eliminating the effect of PCB SW01D-G2 in LPSD internal flooding analysis, or approximately $250.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($29,896) and AOC ($40,417), total only $70,313 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the circuit breaker, then an estimated maximum total benefit of approximately $84,100 would occur.

The total maximum benefit would be much lower than $84,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-35 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.10 SAT Transformer Event Summary Evaluating both SAT transformer events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all SAT transformer unavailability is approximately $16,100. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($17,845) and AOC ($21,062), total only $38,907 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the transformer, then an estimated maximum total benefit of approximately $55,000 would occur.

The total maximum benefit would be much lower than $55,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the transformer would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.9.11 4.16KV Circuit Breaker Event Summary Evaluating all 4.16KV circuit breaker events above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all 4.16KV circuit breakers unavailability is approximately $81,900. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only

$105,677. If all offsite consequences were abated by eliminating any risk contribution from 4.16kV breakers, then an estimated maximum total benefit of approximately $187,500 would occur.

The total maximum benefit would be much lower than $187,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the circuit breaker would have a negligible effect on reducing risk from 7-36 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification SGTR and ISLOCA events. Furthermore, the change would need to be applied to all seven circuit breakers considered in this estimate.

7.10 POSRV Events 7.10.1 POSRV V200 Events Basic events for the unavailability of POSRV V200 are present in the At-Power internal flooding events, At-Power internal fire events, and LPSD internal event cutset file FV importance analyses and include: Table 6b (Item 84), Table 6c (Item 90), and Table 7d (Item 61). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V200 unavailability in the At-Power internal flooding events analysis, or approximately $270. A maximum of 0.8% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V200 unavailability in the At-Power fire events analysis, or approximately $2,400. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V200 unavailability in the LPSD internal events analysis, or approximately $360.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($27,244) and AOC ($33,484), total only $60,728 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the POSRV, then an estimated maximum total benefit of approximately

$63,800 would occur.

The total maximum benefit would be much lower than $63,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of a POSRV would affect only induced SGTR events.

7.10.2 POSRV V201 Events Basic events for the unavailability of POSRV V201 are present in the At-Power internal flooding events, at-power internal fire events, and LPSD internal events cutset file FV importance analyses and include: Table 6b (Item 85), Table 6c (Item 91), and Table 7d (Item 61). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V201 unavailability in the At-Power internal flooding events analysis, or approximately $270. A maximum of 0.8% reduction in AOE and 7-37 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification AOSC costs is possible by eliminating the effect of POSRV V201 unavailability in the At-Power fire events analysis, or approximately $2,400. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V201 unavailability in the LPSD internal events analysis, or approximately $360.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($27,244) and AOC ($33,484), total only $60,728 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the POSRV, then an estimated maximum total benefit of approximately

$63,800 would occur.

The total maximum benefit would be much lower than $63,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of a POSRV would affect only induced SGTR events.

7.10.3 POSRV V202 Events Basic events for the unavailability of POSRV V202 are present in the At-Power internal flooding events and LPSD internal events cutset file FV importance analyses and include:

Table 6b (Item 88) and Table 7d (Item 61). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V202 unavailability in the At-Power internal flooding events analysis, or approximately $260. A maximum of 0.2%

reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V202 unavailability in the LPSD internal events analysis, or approximately $360.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($10,950) and AOC ($14,414), total only $25,364 for the affected hazrds. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the POSRV, then an estimated maximum total benefit of approximately

$26,000 would occur.

The total maximum benefit would be much lower than $26,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of a POSRV would affect only induced SGTR events.

7-38 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.10.4 POSRV V203 Events Basic events for the unavailability of POSRV V203 are present in the At-Power internal flooding events and LPSD internal events cutset file FV importance analyses and include:

Table 6b (Item 88) and Table 7d (Item 61). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V203 unavailability in the At-Power internal flooding events analysis, or approximately $260. A maximum of 0.2%

reduction in AOE and AOSC costs is possible by eliminating the effect of POSRV V203 unavailability in the LPSD internal events analysis, or approximately $360.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($10,950) and AOC ($14,414), total only $25,364 for the affected hazrds. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the POSRV, then an estimated maximum total benefit of approximately

$26,000 would occur.

The total maximum benefit would be much lower than $26,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of a POSRV would affect only induced SGTR events.

7.10.5 Total POSRV Event Summary Evaluating all four POSRV above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all POSRV unavailability is approximately

$7,400. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($27,244) and AOC ($33,484), total only $60,728 for the affected hazards.

If all offsite consequences were abated by eliminating any risk contribution from the POSRVs, then an estimated maximum total benefit of approximately $68,100 would occur.

The total maximum benefit would be much lower than $68,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of a POSRVs would affect only induced SGTR events.

7-39 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.11 Chiller/Cooler Events The generic SAMDA items evaluated for the APR1400 design related to chillers/coolers are listed in Table 5 and include items 80, 81, and 82.

7.11.1 ECW Chiller CH01A Events Basic events for the unavailability of ECW chiller CH01A are present in At-Power internal events, At-Power internal flooding, At-Power internal fire events, LPSD internal events, and LPSD internal flood cutset file FV importance analyses and include: Table 6a (Items 46, 60, and 96), Table 6b (Item 74), Table 6c (Items 56, 62, 81, and 118), Table 6d (Item 61), and Table 6e (Item 50). A maximum of 5.0% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01A unavailability in the At-Power internal events analysis, or approximately $5,200. A maximum of 0.9% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01A unavailability in the At-Power internal flooding analysis, or approximately $360. A maximum of 4.3%

reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01A unavailability in the At-Power fire events analysis, or approximately $12,600.

A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01A unavailability in the LPSD internal events analysis, or approximately $1,500. A maximum of 0.9% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01A unavailability in the LPSD internal events analysis, or approximately $80.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the transformer, then an estimated maximum total benefit of approximately $125,400 would occur.

The total maximum benefit would be much lower than $125,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an ECW chiller would have a minimal effect of SGTR and ISLOCA events.

7-40 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.11.2 ECW Chiller CH01B Events Basic events for the unavailability of ECW chiller CH01B are present in At-Power internal events, At-Power internal flood, At-Power internal fire, LPSD internal events cutset file FV importance analyses and include: Table 6a (Items 47, 60, 96), Table 6b (Item 101), Table 6c (Items 56, 75 and 118), and Table 6d (Item 61). A maximum of 4.8% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01B unavailability in the At-Power internal events analysis, or approximately $5,000. A maximum of 0.6% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01B unavailability in the At-Power internal flooding analysis, or approximately $230. A maximum of 3.0% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01B unavailability in the At-Power fire events analysis, or approximately $8,700.

A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH01B unavailability in the LPSD internal events analysis, or approximately $1,500.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($42,244) and AOC ($55,064), total only $97,308 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the transformer, then an estimated maximum total benefit of approximately $112,700 would occur.

The total maximum benefit would be much lower than $112,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an ECW chiller would have a minimal effect of SGTR and ISLOCA events.

7.11.3 ECW Chiller CH02A Events Basic events for the unavailability of ECW chiller CH03a are present in nearly all of the cutset file FV importance analyses and include: Table 6a (Items 28, 60, 79, and 96), Table 6b (Items 16, and 48), Table 6c (Items 24, 56, 77, and 118), and Table 6d (Item 61). A maximum of 7.8% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02A unavailability in the At-Power internal events analysis, or approximately $8,100. A maximum of 9.1% reduction in AOE and AOSC costs is 7-41 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification possible by eliminating the effect of ECW chiller CH02A unavailability in the At-Power internal flooding events analysis, or approximately $3,600. A maximum of 6.2%

reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02A unavailability in the At-Power fire events analysis, or approximately $18,200.

A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02A unavailability in the LPSD internal events analysis, or approximately $1,500.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($42,244) and AOC ($55,064), total only $97,308 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the transformer, then an estimated maximum total benefit of approximately $128,600 would occur.

The total maximum benefit would be much lower than $128,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an ECW chiller would have a minimal effect of SGTR and ISLOCA events.

7.11.4 ECW Chiller CH02B Events Basic events for the unavailability of ECW chiller CH02B are present in nearly all of the cutset file FV importance analyses and include: Table 6a (Items 29, 60, 85, and 96), Table 6b (Items 17 and 50), Table 6c (Items 30, 56, 87, and 118), Table 6d (Item 61), and Table 6e (Item 16). A maximum of 7.4% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02B unavailability in the At-Power internal events analysis, or approximately $7,800. A maximum of 8.7% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02B unavailability in the At-Power internal flooding events analysis, or approximately $3,400. A maximum of 5.7%

reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02B unavailability in the At-Power fire events analysis, or approximately $16,500.

A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW chiller CH02B unavailability in the LPSD internal events analysis, or approximately $1,500. A maximum of 5.0% reduction in AOE and AOSC costs is 7-42 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification possible by eliminating the effect of ECW chiller CH02B unavailability in the LPSD internal flooding analysis, or approximately $420.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the chiller, then an estimated maximum total benefit of approximately

$135,200 would occur.

The total maximum benefit would be much lower than $135,200 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of an ECW chiller would have a minimal effect of SGTR and ISLOCA events.

7.11.5 EDG Room Cubical Cooler HV12A Events Basic events for the unavailability of EDG room cubical cooler HV12A are present in the At-Power internal events, At-Power internal fire, LPSD internal events, and LPSD internal flood cutset file FV importance analysis and include: Table 6a (Items 118), Table 6e (Items 23 and 46), Table 7c (Items 10), and Table 7d (Item 51). A maximum of 0.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12A unavailability in the At-Power internal events analysis, or approximately $580. A maximum of 0.4% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12A unavailability in the At-Power internal fire analysis, or approximately $1,100.

A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12A unavailability in the LPSD internal events analysis, or approximately $920. A maximum of 4.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12A unavailability in the LPSD internal flooding analysis, or approximately $340.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($44,639) and AOC ($57,495), total only $102,134 for the at-power events. If all offsite consequences were abated by eliminating any risk contribution from the EDG room cooler, then an estimated maximum total benefit of approximately $105,100 would occur.

7-43 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $105,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room cooler would have a minimal effect of SGTR and ISLOCA events.

7.11.6 EDG Room Cubical Cooler HV12B Events Basic events for the unavailability of EDG room cubical cooler HV12B are present in the At-Power internal event, At-Power internal fire, and LPSD internal events cutset file FV importance analysis and include: Table 6a (Items 122), Table 7c (Item 10), and Table 7d (Item 49). A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12B unavailability in the At-Power internal events analysis, or approximately $540. A maximum of 0.4% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12B unavailability in the At-Power internal fire analysis, or approximately $1,100. A maximum of 0.5%

reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV12B unavailability in the LPSD internal events analysis, or approximately $920.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($40,693) and AOC ($53,072), total only $93,765 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG room cooler, then an estimated maximum total benefit of approximately $96,300 would occur.

The total maximum benefit would be much lower than $96,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room cooler would have a minimal effect of SGTR and ISLOCA events.

7.11.7 EDG Room Cubical Cooler HV12D Events Basic events for the unavailability of EDG room cubical cooler HV12D are present in only the LPSD internal flooding cutset file FV importance analysis and include: Table 6e (Item 55). A maximum of 0.9% reduction in AOE and AOSC costs is possible by eliminating 7-44 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification the effect of cubical cooler HV12D unavailability in the LPSD internal floodinig analysis, or approximately $80.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($3,946) and AOC ($4,423), total only $8,369 for the LPSD internal events. If all offsite consequences were abated by eliminating any risk contribution from the EDG room cooler, then an estimated maximum total benefit of approximately $8,400 would occur.

The total maximum benefit would be much lower than $8,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room cooler would have a minimal effect of SGTR and ISLOCA events.

7.11.8 EDG Room Cubical Cooler HV13A Events Basic events for the unavailability of EDG room cubical cooler HV13A are present in the At-Power internal event, at-power internal fire, LPSD internal events, and LPSD internal flood cutset file FV importance analysis and include: Table 6a (Items 119) Table 6e (Items 24 and 47), Table 7c (Item 10), and Table 7d (Item 52). A maximum of 0.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13A unavailability in the At-Power internal events analysis, or approximately $580. A maximum of 0.4% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13A unavailability in the At-Power internal fire analysis, or approximately $1,100.

A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13A unavailability in the LPSD internal events analysis, or approximately $920. A maximum of 4.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13A unavailability in the LPSD internal flood analysis, or approximately $340.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($44,639) and AOC ($57,495), total only $102,134 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG room cooler, then an estimated maximum total benefit of approximately $105,100 would occur.

7-45 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $105,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room cooler would have a minimal effect of SGTR and ISLOCA events.

7.11.9 EDG Room Cubical Cooler HV13B Events Basic events for the unavailability of EDG room cubical cooler HV13B are present in the At-Power internal events, At-Power internal fire, and LPSD internal events cutset file FV importance analysis and include: Table 6a (Items 123), Table 7c (Item 10), and Table 7d (Item 50). A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13B unavailability in the At-Power internal events analysis, or approximately $540. A maximum of 0.4% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13B unavailability in the At-Power internal fire analysis, or approximately $1,100. A maximum of 0.5%

reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV13B unavailability in the LPSD internal events analysis, or approximately $930.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($40,693) and AOC ($53,072), total only $93,765 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG room cooler, then an estimated maximum total benefit of approximately $96,300 would occur.

The total maximum benefit would be much lower than $96,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room cooler would have a minimal effect of SGTR and ISLOCA events.

7.11.10 EDG Room Cubical Cooler HV13D Events Basic events for the unavailability of EDG room cubical cooler HV13D are present in only the LPSD internal flood cutset file FV importance analysis and include: Table 6e (Item 56). A maximum of 0.9% reduction in AOE and AOSC costs is possible by eliminating 7-46 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification the effect of cubical cooler HV13D unavailability in the LPSD internal flood analysis, or approximately $80.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($3,946) and AOC ($4,423), total only $8,369 for the LPSD flooding events. If all offsite consequences were abated by eliminating any risk contribution from the EDG room cooler, then an estimated maximum total benefit of approximately $8,400 would occur.

The total maximum benefit would be much lower than $8,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room cooler would have a minimal effect of SGTR and ISLOCA events.

7.11.11 Motor Driven AFW Pump Room A Cubical Cooler HV33A Events Basic events for the unavailability of motor driven AFW pump room A cubical cooler HV33A are present in the At-Power internal events, At-Power internal flood, At-Power internal fire, and LPSD internal events cutset file FV importance analyses and include:

Table 6a (Item 89), Table 6b (Items 46 and 82), Table 6c (Items 33 and 89) and Table 7d (Item 44). A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33A unavailability in the At-Power internal events analysis, or approximately $1,100. A maximum of 3.5% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33A unavailability in the At-Power internal flooding events analysis, or approximately $1,400. A maximum of 3.5% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33A1 unavailability in the At-Power fire events analysis, or approximately

$10,000.

A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33A unavailability in the LPSD internal events analysis, or approximately $180.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($42,244) and AOC ($55,064), total only $97,308 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk 7-47 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification contribution from the MDAFW pump room cooler, then an estimated maximum total benefit of approximately $110,000 would occur.

The total maximum benefit would be much lower than $110,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MDAFW pump room cooler would have a minimal effect only induced SGTR events by increasing availability of the associated AFW pump.

7.11.12 Motor Driven AFW Pump Room B Cubical Cooler HV33B Events Basic events for the unavailability of motor driven AFW pump room B cubical cooler HV33B are present in the At-Power internal flooding, at-power internal fire, and LPSD internal events cutset file FV importance analyses and include: Table 6b (Items 51 and 94), Table 6c (Items 71), and Table 7d (Item 44). A maximum of 2.6% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the At-Power internal flooding events analysis, or approximately $1,000.

A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the At-Power fire events analysis, or approximately $3,300. A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the LPSD events analysis, or approximately $180.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($27,244) and AOC ($33,484), total only $60,728 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the MDAFW pump room cooler, then an estimated maximum total benefit of approximately $65,200 would occur.

The total maximum benefit would be much lower than $65,200 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MDAFW pump room cooler would have a minimal effect only induced SGTR events by increasing availability of the associated AFW pump.

7-48 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.11.13 ECW Chiller B Cubical Cooler HV32B Events Basic events for the unavailability of ECW Chiller room cubical cooler HV32B are present in the LPSD internal events and LPSD internal flooding cutset file FV importance analyses and include: Table 6e (Item 49), and Table 7d (Item 44). A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV32B unavailability in the LPSD internal events analysis, or approximately $180. A maximum of 0.9% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV32B unavailability in the LPSD internal flood events analysis, or approximately

$80.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($13,345) and AOC ($16,845), total only $30,190 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the ECW chiller cubical cooler, then an estimated maximum total benefit of approximately $30,400 would occur.

The total maximum benefit would be much lower than $30,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW chiller cubical cooler would have a minimal effect on SGTR and ISLOCA events 7.11.14 Air Handling Unit AH02A Events Basic events for the unavailability of air handling unit AH02A are present in the At-Power internal flooding and LPSD internal events FV importance analyses and include: Table 6b (Items 102 and 105) and Table 7d (Item 42). A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the At-Power internal flooding events analysis, or approximately $460. A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the LPSD internal events analysis, or approximately $180.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($10,950) and AOC ($14,414), total only $25,364 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk 7-49 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification contribution from the ECW chiller cubical cooler, then an estimated maximum total benefit of approximately $26,000 would occur.

The total maximum benefit would be much lower than $26,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW chiller cubical cooler would have a minimal effect only induced SGTR and ISLOCA events.

7.11.15 Air Handling Unit AH02B Events Basic events for the unavailability of air handling unit AH02B are present in the At-Power internal flooding, LPSD internal events, and LPSD internal flood FV importance analyses and include: Table 6b (Items 104 and 106), Table 6e (Item 33), and Table 7d (Item 42).

A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the At-Power internal flooding events analysis, or approximately $460. A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of cubical cooler HV33B unavailability in the LPSD internal events analysis, or approximately $180.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($14,896) and AOC ($18,837), total only $33,733 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the ECW chiller cubical cooler, then an estimated maximum total benefit of approximately $34,500 would occur.

The total maximum benefit would be much lower than $34,5000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW chiller cubical cooler would have a minimal effect only induced SGTR and ISLOCA events.

7.11.16 Total ECW Chiller Event Summary Evaluating all four ECW chillers above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all ECW chiller unavailability is 7-50 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification approximately $95,900. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 for the affected hazards. If all offsite consequences were abated by eliminating any risk contribution from the ECW chillers, then an estimated maximum total benefit of approximately $201,600 would occur.

The total maximum benefit would be much lower than $201,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW chillers would have a minimal effect of SGTR and ISLOCA events.

7.11.17 Total EDG Room Cubical Cooler Event Summary Evaluating all six EDG room cubical coolers above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all EDG room cooler unavailability is approximately $8,600. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($44,639) and AOC ($57,495), total only

$102,134 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG room coolers, then an estimated maximum total benefit of approximately $110,700 would occur.

The total maximum benefit would be much lower than $110,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the EDG room coolers would have a minimal effect of SGTR and ISLOCA events.

7.11.18 Total Motor Driven AFW Pump Room Cubical Cooler Event Summary Evaluating both motor-driven AFW pump room cubical coolers above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all MDAFW pump room cooler unavailability is approximately $17,200. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($42,244) and AOC ($55,064), total only $97,308. If all offsite consequences were abated by 7-51 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification eliminating any risk contribution from the MDAFW pump room coolers, then an estimated maximum total benefit of approximately $114,500 would occur.

The total maximum benefit would be much lower than $114,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MDAFW pump room coolers would affect only induced SGTR events by increasing availability of the associated AFW pump.

7.11.19 Total Air Handling Unit Event Summary Evaluating the two air handling units above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all AHU unavailability is approximately

$1,400. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($14,896) and AOC ($18,837), total only $33,733 for the affected hazards.

If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the EDG room coolers, then an estimated maximum total benefit of approximately $35,100 would occur.

The total maximum benefit would be much lower than $35,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the air handling units would have a minimal effect of SGTR and ISLOCA events.

7.12 Safety Injection (SI) Events The generic SAMDA items evaluated for the APR1400 design related to safety injection are listed in Table 4 and include items 26, 29, 37, 38, and 39.

7.12.1 SI Pump PP02A Events Basic events for the unavailability of SI pump PP02A are present only the LPSD internal flooding cutset file FV importance analyses and include: Table 6e (Item 48). A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect 7-52 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification of SI pump PP02A unavailability in the LPSD internal flooding events analysis, or approximately $90.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($3,946) and AOC ($4,423), total only $8,369 for LPSD flooding events. If all offsite consequences were abated by eliminating any risk contribution from the SI pump, then an estimated maximum total benefit of approximately $8,500 would occur.

The total maximum benefit would be much lower than $8,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SI pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.12.2 SI Pump PP02B Events Basic events for the unavailability of SI pump PP02B are present only the At-Power internal events, At-Power internal fire, and LPSD internal flooding cutset file FV importance analyses and include: Table 6a (Item 106), Table 6c (Item 114), and Table 6e (Item 48). A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02B unavailability in the At-Power internal events analysis, or approximately $700. A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02B unavailability in the At-Power internal events analysis, or approximately $700. A maximum of 0.6% reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02B unavailability in the At-Power internal fire analysis, or approximately $1,600. A maximum of 1.1%

reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02B unavailability in the LPSD internal flooding analysis, or approximately $90.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($35,240) and AOC ($45,073), total only $80,313 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the SI pump, then an estimated maximum total benefit of approximately

$82,800 would occur.

The total maximum benefit would be much lower than $82,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the 7-53 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SI pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.12.3 SI Pump PP02C Events Basic events for the unavailability of SI pump PP02C are present in only the At-Power internal events, At-power internal fire, and LPSD internal events cutset file FV importance analyses and include: Table 6a (Items 95 and 121), Table 6c (Item 108), and Table 6d (Item 74). A maximum of 1.4% reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02C unavailability in the At-Power internal events analysis, or approximately $1,400. A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02C unavailability in the LPSD internal events analysis, or approximately $1,100.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($24,399) and AOC ($34,002), total only $58,401 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the SI pump, then an estimated maximum total benefit of approximately

$60,900 would occur.

The total maximum benefit would be much lower than $60,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SI pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.12.4 SI Pump PP02D Events Basic events for the unavailability of SI pump PP02D are present only the At-Power internal fire cutset file FV importance analyses and include: Table 6c (Item 108). A maximum of 0.6% reduction in AOE and AOSC costs is possible by eliminating the effect of SI pump PP02D unavailability in the At-Power internal fire events analysis, or approximately $1,800.

7-54 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($16,294) and AOC ($19,070), total only $35,364 for At-Power internal fire. If all offsite consequences were abated by eliminating any risk contribution from the SI pump, then an estimated maximum total benefit of approximately $37,200 would occur.

The total maximum benefit would be much lower than $37,200 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SI pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.12.5 Total SI Pump Event Summary Evaluating all four SI pumps above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all SI pump unavailability is approximately

$6,800. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($35,240) and AOC ($45,073), total only $80,313. If all offsite consequences were abated by eliminating any risk contribution from the SI pumps, then an estimated maximum total benefit of approximately $87,100 would occur.

The total maximum benefit would be much lower than $87,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SI pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.12.6 IRWST Strainer Events Basic events for the unavailability of IRWST sump are present in only the At-Power and LPSD internal events cutset file FV importance analyses and include: Table 6a (Item 34) and Table 6d (Item 13). A maximum of 3.4% reduction in AOE and AOSC costs is possible by eliminating the effect of IRWST sump unavailability in the At-Power internal events analysis, or approximately $3,500.

7-55 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification A maximum of 5.4% reduction in AOE and AOSC costs is possible by eliminating the effect of IRWST sump unavailability in the LPSD internal events analysis, or approximately $10,900.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($24,399) and AOC ($34,002), total only $58,401 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the IRWST sump, then an estimated maximum total benefit of approximately $72,800 would occur.

The total maximum benefit would be much lower than $72,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the IRWST sump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.12.7 SI Valve V-959 Events Basic events for the unavailability of SI pump min-flow recirculation valve V-959 are present only the At-Power fire cutset file FV importance analyses and include: Table 6c (Item 68). A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of the recirculation valve unavailability in the At-Power internal fire events analysis, or approximately $3,400.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($16,294) and AOC ($19,070), total only $35,364 for the At-Power fire events. If all offsite consequences were abated by eliminating any risk contribution from the valve, then an estimated maximum total benefit of approximately $38,700 would occur.

The total maximum benefit would be much lower than $38,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the recirculation valve would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7-56 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.13 ESW Events The generic SAMDA items evaluated for the APR1400 design related to the ESW system are listed in Table 5 and include items 43, 46, and 47.

7.13.1 ESW Pump PP02A Events Basic events for the unavailability of ESW pump PP02A are present in the At-Power internal events, At-Power internal flooding events, At-Power internal fire, and LPSD internal events cutset file FV importance analyses and include: Table 6a (Item 49), Table 6b (Item 28), Table 6c (Item 64), and Table 7d (Item 63). A maximum of 2.2% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02A unavailability in the At-Power internal events analysis, or approximately $2,300. A maximum of 4.3% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02A unavailability in the At-Power internal flooding events analysis, or approximately $1,700. A maximum of 1.3% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02A unavailability in the At-Power internal fire events analysis, or approximately $3,700. A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02A unavailability in the LPSD internal events analysis, or approximately $140.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($42,244) and AOC ($55,064), total only $97,308 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the ECW pump, then an estimated maximum total benefit of approximately $105,100 would occur.

The total maximum benefit would be much lower than $105,100 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ESW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.2 ESW Pump PP02B Events Basic events for the unavailability of ESW pump PP02B are present in the At-Power internal events, At-Power internal flooding events, At-Power internal fire, LPSD internal 7-57 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification events, and LPSD internal flood cutset file FV importance analyses and include: 6a (Item 53), Table 6b (Item 29), Table 6c (Item 60), Table 6e (Item 67), and Table 7d (Item 63).

A maximum of 2.1% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02B unavailability in the At-Power internal events analysis, or approximately $2,100. A maximum of 4.2% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02B unavailability in the At-Power internal flooding events analysis, or approximately $1,600. A maximum of 1.4%

reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02B unavailability in the At-Power internal fire analysis, or approximately $4,000.

A maximum of 0.1% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02B unavailability in the LPSD internal events analysis, or approximately $140. A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW pump PP02B unavailability in the LPSD internal flooding events analysis, or approximately $40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the ESW pump, then an estimated maximum total benefit of approximately $113,700 would occur.

The total maximum benefit would be much lower than $113,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ESW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.3 ESW Filter Plugging Events Basic events for plugging of all ESW filters are present in the At-Power internal events, At-Power internal fire, and LPSD internal flood cutset file FV importance analysis and include:

Table 6a (Item 48), Table 6c (Item 35), and Table 6e (Item 69). A maximum of 2.4%

reduction in AOE and AOSC costs is possible by eliminating the effect of ESW filter unavailability in the At-Power internal events analysis, or approximately $2,400. A maximum of 2.4% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW filter unavailability in the At-Power internal fire analysis, or approximately $7,000.

7-58 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of ESW filter unavailability in the LPSD internal flooding analysis, or approximately

$40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($35,240) and AOC ($45,073), total only $80,313 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the ESW filters, then an estimated maximum total benefit of approximately $89,800 would occur.

The total maximum benefit would be much lower than $89,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ESW filters would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.4 ESW CT01A Events Basic events for the unavailability of ESW Cooling Tower CT01A are present in the At-Power internal fire and LPSD internal events cutset file FV importance analysis and include:

Table 7c (Item 15) and Table 7d (Item 27). A maximum of 0.3% reduction in AOE and AOSC costs is possible by eliminating the effect of CT01A unavailability in the At-Power internal fire analysis, or approximately $750. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CT01A unavailability in the LPSD internal events analysis, or approximately $320.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($25,693) and AOC ($31,492), total only $57,185 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from CT01A, then an estimated maximum total benefit of approximately

$58,300 would occur.

The total maximum benefit would be much lower than $58,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved 7-59 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification performance of CT01A would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.5 ESW CT01B Events Basic events for the unavailability of ESW Cooling Tower CT01B are present in the At-Power internal fire and LPSD internal events cutset file FV importance analysis and include:

Table 7c (Item 15) and Table 7d (Item 27). A maximum of 0.3% reduction in AOE and AOSC costs is possible by eliminating the effect of CT01B unavailability in the At-Power internal fire analysis, or approximately $750. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CT01B unavailability in the LPSD internal events analysis, or approximately $320.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($25,693) and AOC ($31,492), total only $57,185 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from CT01B, then an estimated maximum total benefit of approximately

$58,300 would occur.

The total maximum benefit would be much lower than $58,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of CT01B would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.6 ESW CT02A Events Basic events for the unavailability of ESW Cooling Tower CT02A are present in the At-Power internal flooding, At-Power internal fire, and LPSD internal events cutset file FV importance analysis and include: Table 6b (Item 100), Table 7c (Item 15), and Table 7d (Item 27). A maximum of 0.6% reduction in AOE and AOSC costs is possible by eliminating the effect of CT02A unavailability in the At-Power internal flooding analysis, or approximately $230. A maximum of 0.3% reduction in AOE and AOSC costs is possible by eliminating the effect of CT02A unavailability in the At-Power internal fire analysis, or approximately $750. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CT02A unavailability in the LPSD internal events analysis, or approximately $320.

7-60 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($27,244) and AOC ($33,484), total only $60,728 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from CT02A, then an estimated maximum total benefit of approximately

$62,000 would occur.

The total maximum benefit would be much lower than $62,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of CT02A would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.7 ESW CT02B Events Basic events for the unavailability of ESW Cooling Tower CT02B are present in the At-Power internal flooding, At-Power internal fire, LPSD internal events, and LPSD internal flooding cutset file FV importance analysis and include: Table 6b (Item 103), Table 6e (Items 30 and 53), Table 7c (Item 15), and Table 7d (Item 27). A maximum of 0.6%

reduction in AOE and AOSC costs is possible by eliminating the effect of CT02B unavailability in the At-Power internal flooding analysis, or approximately $230. A maximum of 0.3% reduction in AOE and AOSC costs is possible by eliminating the effect of CT02B unavailability in the At-Power internal fire analysis, or approximately $750. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CT02B unavailability in the LPSD internal events analysis, or approximately $320. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of CT02B unavailability in the LPSD internal flooding analysis, or approximately $200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($31,190) and AOC ($37,907), total only $69,097 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from CT02B, then an estimated maximum total benefit of approximately

$70,600 would occur.

The total maximum benefit would be much lower than $70,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events 7-61 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of CT02B would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.8 ESW HOV-074 Events Basic events for the unavailability of ESW Hydraulic-operated valve HOV-074 are present in the LPSD internal flooding cutset file FV importance analysis and include: Table 6e (Item 76). A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of HOV-074 unavailability in the LPSD internal flooding events analysis, or approximately $40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($3,946) and AOC ($4,423), total only $8,369 for LPSD flooding events. If all offsite consequences were abated by eliminating any risk contribution from HOV-074, then an estimated maximum total benefit of approximately $8,400 would occur.

The total maximum benefit would be much lower than $8,400 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of HOV-074 would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.13.9 Total ESW Pump Events Summary Evaluating all both ESW pumps above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all ESW pump unavailability is approximately $15,800. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($46,190) and AOC ($59,487), total only $105,677.

If all offsite consequences were abated by eliminating any risk contribution from the ESW pumps, then an estimated maximum total benefit of approximately $121,500 would occur.

The total maximum benefit would be much lower than $121,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ESW pumps would have a minimal effect of SGTR and ISLOCA events.

7-62 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 7.13.10 Total ESW Cooling Tower Events Summary Evaluating all four ESW cooling towers above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all ESW cooling tower unavailability is approximately $5,000. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($31,190) and AOC ($37,907), total only $69,097.

If all offsite consequences were abated by eliminating any risk contribution from the ESW pumps, then an estimated maximum total benefit of approximately $74,000 would occur.

The total maximum benefit would be much lower than $74,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ESW cooling towers would have a minimal effect of SGTR and ISLOCA events.

7.14 ECW Events 7.14.1 ECW Pump PP02A Events Basic events for the unavailability of ECW pump PP02A are present in the At-Power internal events, At-Power internal flooding, and At-Power internal fire event cutset file FV importance analyses and include: Table 6a (Item 70), Table 6b (Item 44), Table 6c (Item 82), and Table 7c (Item 24). A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02A unavailability in the At-Power internal events analysis, or approximately $1,100. A maximum of 2.5% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02A unavailability in the At-Power internal flooding events analysis, or approximately $1,000. A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02A unavailability in the At-Power internal fire analysis, or approximately $3,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($32,845) and AOC ($42,642), total only $75,487 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the ECW pump, then an estimated maximum total benefit of approximately $80,800 would occur.

7-63 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $80,800 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.14.2 ECW Pump PP02B Events Basic events for the unavailability of ECW pump PP02B are present in the At-Power internal events, At-Power internal flooding, and At-Power internal fire, and LPSD internal flood event cutset file FV importance analyses and include: Table 6a (Item 76) Table 6b (Item 47), Table 6c (Item 92), Table 6e (Item 68), and Table 7c (Item 24). A maximum of 1.2% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02B unavailability in the At-Power internal events analysis, or approximately

$1,300. A maximum of 2.2% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02B unavailability in the At-Power internal flooding events analysis, or approximately $880. A maximum of 1.0% reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02B unavailability in the At-Power internal fire analysis, or approximately $3,000. A maximum of 0.5%

reduction in AOE and AOSC costs is possible by eliminating the effect of ECW pump PP02B unavailability in the LPSD internal flooding events analysis, or approximately $40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($36,791) and AOC ($47,065), total only $83,856 for the affected hazards. If all offsite consequences from the affected hazards were abated by eliminating any risk contribution from the ECW pump, then an estimated maximum total benefit of approximately $89,000 would occur.

The total maximum benefit would be much lower than $89,000 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

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APR1400 Applicants Environmental Report - Standard Design Certification 7.14.3 Total ECW Pump Event Summary Evaluating all both ECW pumps above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all ECW pump unavailability is approximately $10,400. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($36,791) and AOC ($47,065), total only $83,856 for the affected hazards. If all offsite consequences from the affected hazards were abated by eliminating any risk contribution from the ECW pumps, then an estimated maximum total benefit of approximately $94,300 would occur.

The total maximum benefit would be much lower than $94,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the ECW pumps would have a minimal effect of SGTR and ISLOCA events.

7.15 SCRAM Due To Mechanical Failure Events The generic SAMDA items evaluated for the APR1400 design related to the ATWS system are listed in Table 5 and include items 130, 131, 132, and 136.

Basic events for SCRAM failure caused by mechanical failures are present in only the At-Power internal events cutset file FV importance analysis and include: Table 6a (Item 50).

A maximum of 2.2% reduction in AOE and AOSC costs is possible by eliminating the mechanical SCRAM failures in the At-Power internal events analysis, or approximately

$2,200.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for At-Power internal events. If all offsite consequences were abated by eliminating any risk contribution from the mechanical failures that prevent a SCRAM, then an estimated maximum total benefit of approximately $38,900 would occur.

The total maximum benefit would be much lower than $38,900 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved 7-65 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification performance of the ECW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.16 Control Software Events 7.16.1 PPS Loop Controller Application Software Events Basic events for the common cause failure of PPS loop controller application software are present in the At-Power internal events, At-Power internal flooding, At-Power internal fire event, and LPSD internal events cutset file FV importance analyses and include: Table 6a (Item 41), Table 6b (Item 21), Table 6c (Item 12), and Table 6d (Item 21). A maximum of 2.9% reduction in AOE and AOSC costs is possible by eliminating the effect of loop controller application software failures in the At-Power internal events analysis, or approximately $3,000. A maximum of 5.3% reduction in AOE and AOSC costs is possible by eliminating the effect of loop application controller software failures in the At-Power internal flooding events analysis, or approximately $2,100. A maximum of 5.0%

reduction in AOE and AOSC costs is possible by eliminating the effect of loop controller application software failures in the At-Power internal fire analysis, or approximately

$14,500. A maximum of 4.1% reduction in AOE and AOSC costs is possible by eliminating the effect of loop controller application software failures in the LPSD internal events analysis, or approximately $8,300.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($42,244) and AOC ($55,064), total only $97,308 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from loop controller application software failures, then an estimated maximum total benefit of approximately $125,300 would occur.

The total maximum benefit would be much lower than $125,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the loop controller application software would have a negligible effect on reducing risk from SGTR and ISLOCA events.

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APR1400 Applicants Environmental Report - Standard Design Certification 7.16.2 PPS Group Controller Application Software Events Basic events for the common cause failure of PPS group controller application software are present in the At-Power internal events cutset file FV importance analyses and include:

Table 6a (Item 92). A maximum of 0.9% reduction in AOE and AOSC costs is possible by eliminating the effect of group controller application software failures in the At-Power internal events analysis, or approximately $1,000.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from group controller application software failures, then an estimated maximum total benefit of approximately $37,500 would occur.

The total maximum benefit would be much lower than $37,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the group controller application software would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.16.3 PPS Loop Controller Operating System Software Events Basic events for the common cause failure of PPS loop controller operating system software are present in the At-Power internal fire event and LPSD internal events cutset file FV importance analyses and include: Table 6c (Item 120) and Table 7d (Item 29). A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of loop controller operating system software failures in the At-Power internal fire analysis, or approximately $1,400. A maximum of 0.4% reduction in AOE and AOSC costs is possible by eliminating the effect of loop controller operating system software failures in the LPSD internal events analysis, or approximately $800.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($25,693) and AOC ($31,492), total only $57,185 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from loop controller operating system software failures, then an estimated maximum total benefit of approximately $59,500 would occur.

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APR1400 Applicants Environmental Report - Standard Design Certification The total maximum benefit would be much lower than $59,500 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the loop controller operating system software would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.17 Main Steam Events The generic SAMDA items evaluated for the APR1400 design related to main steam are listed in Table 5 and include item 89.

7.17.1 Main Steam Atmospheric Dump Valve (V-102)

Basic events for the unavailability of MS ADV V-102 are present in the At-Power internal events and LPSD internal fire event cutset file FV importance analyses and include: Table 7a (Item 9) and Table 7f (Item 17). A maximum of 0.3% reduction in AOE and AOSC costs is possible by eliminating the effect of MS ADV V-102 unavailability in the At-Power internal events analysis, or approximately $300. A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of MS ADV V-102 unavailability in the LPSD internal fire analysis, or approximately $780.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($18,687) and AOC ($26,026), total only $44,713 for the affected hazards. If all offsite consequences from the affected hazards were abated by eliminating any risk contribution from the ADV, then an estimated maximum total benefit of approximately

$45,800 would occur.

The total maximum benefit would be much lower than $45,800 because all offsite consequences would not be eliminated.

7.17.2 Main Steam Isolation Valves Basic events for the common cause failure of all MSIVs to close are present in the At-Power internal events cutset file FV importance analyses and include: Table 6a (Items112, 113, 114, and 115) and Table 7a (Items 5, 6, 7, 8, and 11). A maximum of 4.2% reduction in AOE and AOSC costs is possible by eliminating the effect of MSIVs in the At-Power internal events analysis, or approximately $4,300.

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APR1400 Applicants Environmental Report - Standard Design Certification Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($15,000) and AOC ($21,580), total only $36,580 for the affected hazards. If all offsite consequences from the affected hazards were abated by eliminating any risk contribution from the MSIVs, then an estimated maximum total benefit of approximately

$40,900 would occur.

The total maximum benefit would be much lower than $40,900 because all offsite consequences would not be eliminated.

7.17.3 Main Steam Safety Valves Basic events for the common cause failure of all MSSVs to open are present in the At-Power internal events and At-Power internal flooding cutset file FV importance analyses and include: Table 7a (Item 3) and Table 7b (Item 2). A maximum of 0.4% reduction in AOE and AOSC costs is possible by eliminating the effect of MSSVs in the At-Power internal events analysis, or approximately $430. A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of MSSVs in the At-Power internal flooding analysis, or approximately $60.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($16,551) and AOC ($23,572), total only $40,123 for the affected hazards. If all offsite consequences from the affected hazards were abated by eliminating any risk contribution from the MSSVs, then an estimated maximum total benefit of approximately

$40,600 would occur.

The total maximum benefit would be much lower than $40,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the MSSVs to open would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.18 TGBCCW Events 7.18.1 TGBCCW Pump Train 2 Events Basic events for the unavailability of TGB CCW pump PP02 are present in the At-Power internal fire event cutset file FV importance analyses and include: Table 6c (Item 105).

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APR1400 Applicants Environmental Report - Standard Design Certification A maximum of 0.7% reduction in AOE and AOSC costs is possible by eliminating the effect of TGBCW pump PP02 unavailability in the At-Power internal fire analysis, or approximately $1,900.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($16,294) and AOC ($19,070), total only $35,364 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the TGBCCW pump, then an estimated maximum total benefit of approximately $37,300 would occur.

The total maximum benefit would be much lower than $37,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the TGBCW pump would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.19 Shutdown Cooling System (SDC) Events 7.19.1 SDC Pump PP01A Events Basic events for the unavailability of SDC PP01A are present in the At-Power and LPSD internal events cutset file FV importance analyses and include: Table 6d (Item 72), Table 7a (Item 10), and Table 7d (Items 28, 30, and 37). A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of SDC PP01A unavailability in the At-Power internal events analysis, or approximately $240. A maximum of 1.0% reduction in AOE and AOSC costs is possible by eliminating the effect of SDC PP01A unavailability in the LPSD internal events analysis, or approximately $2,100.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($24,399) and AOC ($34,002), total only $58,401 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the SDC pump, then an estimated maximum total benefit of approximately $60,700 would occur.

The total maximum benefit would be much lower than $60,700 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events 7-70 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SDC pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.19.2 SDC Pump PP01B Events Basic events for the unavailability of SDC PP01B are present in the At-Power internal events, LPSD internal events, and LPSD internal flooding cutset file FV importance analyses and include: Table 6d (Item 72), Table 6e (Item 65), Table 7a (Item 10), and Table 7d (Items 28, 30, and 37). A maximum of 0.2% reduction in AOE and AOSC costs is possible by eliminating the effect of SDC PP01B unavailability in the At-Power internal events analysis, or approximately $240. A maximum of 1.1% reduction in AOE and AOSC costs is possible by eliminating the effect of SDC PP01B unavailability in the LPSD internal events analysis, or approximately $2,200. A maximum of 0.5% reduction in AOE and AOSC costs is possible by eliminating the effect of SDC PP01B unavailability in the LPSD internal events analysis, or approximately $40.

Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($28,345) and AOC ($38,425), total only $66,770 for the affected hazards. If all offsite consequences for the affected hazards were abated by eliminating any risk contribution from the SDC pump, then an estimated maximum total benefit of approximately $69,300 would occur.

The total maximum benefit would be much lower than $69,300 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SDC pumps would have a negligible effect on reducing risk from SGTR and ISLOCA events.

7.19.3 Total SDC Pump Event Summary Evaluating all both SDC pumps above together, the maximum reduction in AOE and AOSC costs possible by eliminating the effects of all SDC pump unavailability is approximately $4,800. Although the benefit of the change to offsite risks is not calculated explicitly, these costs, APE ($28,345) and AOC ($38,425), total only $66,770 for the affected hazards. If all offsite consequences from the affected hazards were abated by 7-71 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification eliminating any risk contribution from the ECW pumps, then an estimated maximum total benefit of approximately $71,600 would occur.

The total maximum benefit would be much lower than $71,600 because all offsite consequences would not be eliminated. As can be seen from Tables 3a through 3f, the majority of APE is caused by SGTR and ISLOCA events. SGTR and ISLOCA events also cause the majority of AOC, as shown in Tables 4a through 4f. Improved performance of the SDC pumps would have a minimal effect of SGTR and ISLOCA events.

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APR1400 Applicants Environmental Report - Standard Design Certification 8 SAMDA COST EVALUATION For each of the potential SAMDAs discussed in Section 7, an estimate of the minimum costs associated with implementation was made. These cost estimates were based on publicly available information related to nuclear power plant design. Detailed cost estimates are not performed for SAMDA items that show only a small potential benefit.

Rather, once the cost estimates show that a change would exceed the calculated benefit, the evaluations were stopped. Therefore, the costs below may underestimate, greatly, the actual costs of implementing the related modification.

8.1 Emergency Diesel Generator Events The contribution to risk from diesel generator unavailability is related either to station blackout (SBO) scenarios or from the inability to cross-tie containment cooling systems between trains. Much of the risk from these scenarios could be reduced if an alternate means was available to supply power to 480 VAC buses.

As shown in the Palo Verde SAMA analysis (Reference 10), the cost of implementing a 480V portable generator for SBO scenarios would be $1,832,954. Assuming that engineering and procedure updates make up 50% of the cost, such a change would cost at least $900,000.

8.2 AAC CTG Events The costs identified estimated the SAMDAs related to the EDGs in Section 8.1 would apply to SAMDA items for the AAC CTG. Therefore, the minimum costs to eliminate risk from the CTG would be at least $900,000.

8.3 Auxiliary Feedwater Events SAMDA items for the AFW system relate to two types of improvements, isolation valves and pumps. Each of these two types is described below.

8.3.1 AFW Isolation Valve Events The AFW isolation valves are needed for level control when their associated modulating valves become unavailable. The dominant scenarios where this occurs are SBO scenarios where offsite power is not recovered and batteries deplete. Provision of a long-term 8-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification power supply for the AFW modulating valves would obviate the need for the AFW isolation valves to cycle for level control.

Operation of an AFW modulating valve requires power for the control signal as well as power for valve operation. Both the control signal as well as the valve operator rely on the same DC power supply. Therefore, provision of the ability to supply DC power to the train supporting each TDAFPs would eliminate the need for the isolation valves to cycle.

The Vermont Yankee SAMA analysis (Reference 11) estimated the cost for implementing a portable 125V DC generator would be $712,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $350,000. Estimates for providing redundant valves provide even higher costs.

8.3.2 AFW Pump Events Mitigation of AFW pump failure requires that an additional means of steam generator makeup, other than the startup feedwater pump and the four AFW pumps. Feed and bleed cooling is already credited in the PRA so elimination of the risk from AFW pump failure would require either an additional diverse heat removal method or an additional AFW pump.

The Millstone SAMA analysis (Reference 12) estimates the cost of implementing an additional AFW pump to be $12M - $16M. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $6,000,000.

8.4 Fire Barrier Failure Events The PRA results show failure of fire barriers contributing to risk. The barriers of concern are all three-hour rated fire barriers. Therefore, any change to compensate for failure of these barriers would require an additional, diverse method of preventing fires from spreading between the fire areas.

One method of reducing the potential for fires spreading between two areas is to provide an additional active fire detection and suppression system for barriers between zones. For example, a water curtain or deluge system which would spray the area of failed barriers could reduce the potential for inter-area fire propagation.

Brunswick SAMA number 32 (Reference 13) specifically estimated the cost of adding additional automatic fire suppression systems. The estimated cost of implementation is 8-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

$750,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $350,000.

8.5 CCW Events SAMDA items for the CCW system relate to two types of improvements, pumps and containment spray heat exchanger isolation valves. Each of these two types is described below.

8.5.1 CCW Pump Events Mitigation of CCW pump failure requires that an additional means of providing flow through the CCW system. For this item, the simplest means of implementation would be to be to provide an additional CCW pump that could be aligned to either division of CCW thereby using much of the existing piping. For this item, only the costs of the additional pump and driver are estimated. Costs for the switchgear, circuit breakers, and any valves need to operate the pump are neglected.

The Callaway SAMA analysis (Reference 14) estimates the cost of adding an additional CCW pump to cost $1,000,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $500,000.

8.5.2 CS Heat Exchanger Isolation Valves Isolation valves for CCW flow through the containment spray heat exchangers must open to provide long-term containment heat removal. For these scenarios, several hours would be available from the time that the need for containment heat removal has been identified until containment failure would be expected. During this time, manual actions to compensate for failure of the valves could take place.

Addition of a manual valve to provide a bypass around each of the two containment spray heat exchanger CCW isolation valves would allow operator action to compensate for failure of the motor-operated isolation valves to open.

Brunswick SAMA 27 (Reference 13) estimates the cost of a service water cross-tie modification to be $100,000. This modification would involve similar piping and valve installation as required for the CCW heat exchanger valves. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $50,000.

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APR1400 Applicants Environmental Report - Standard Design Certification 8.6 Containment Spray Events SAMDA items for the containment spray system relate to three types of improvements, pumps, containment spray header isolation valves, and containment spray heat exchangers.

Each of these three types is described below.

8.6.1 Containment Spray Pump Events Mitigation of containment spray pump failure requires that an additional means of providing flow through the containment spray system. The APR1400 PRA model credits the shutdown cooling pumps as a means of providing containment spray flow. Therefore, an additional means of providing containment spray flow must be provided. For this item, the simplest means of implementation would be to be to provide an additional containment spray pump that could be aligned to either division of thereby using much of the existing piping.

The Callaway SAMA analysis (Reference 14) estimated the cost for implementing a redundant containment spray system as $2,000,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $1,000,000.

8.6.2 Containment Spray Header Isolation Valves Containment spray header isolation valves must open to allow flow through the containment spray nozzles in order to provide long-term containment heat removal. For these scenarios, several hours would be available from the time that the need for containment heat removal has been identified until containment failure would be expected.

During this time, manual actions to compensate for failure of the valves could take place.

Addition of a manual valve to provide a bypass around each of the two containment spray header isolation valves would allow operator action to compensate for failure of the motor-operated isolation valves.

Brunswick SAMA 27 (Reference 13) estimated the cost of a service water cross-tie modification to be $100,000. This modification would involve similar piping and valve installation as required for the CS bypass valves but would provide for only one valve, not two as would be needed to fully implement the SAMDA on each of the two CS headers.

Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $50,000.

8-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 8.6.3 Containment Spray Heat Exchangers Containment spray heat exchangers are used to provide for long-term containment heat removal. For these scenarios, several hours would be available from the time that the need for containment heat removal has been identified until containment failure would be expected. During this time, manual actions to compensate for failure of the heat exchangers could take place. The APR1400 PRA model credits the shutdown cooling system as a means of heat removal. Therefore, an additional means of providing containment spray heat removal flow must be provided. For this item, the simplest means of implementation would be to be to provide an additional containment spray heat exchanger that could be aligned to either division of thereby using much of the existing piping.

The Callaway SAMA analysis (Reference 14) estimated the cost for implementing a redundant containment spray system as $2,000,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $1,000,000.

8.7 125 VDC Power Events Availability of the station batteries is needed to actuate equipment and maintain instrumentation when normal AC power is lost. For the APR1400 PRA, the leading cause of battery failure is maintenance unavailability. Having a maintenance battery that could be aligned to any one of the four DC trains during battery maintenance would eliminate this contribution to core damage.

As shown in the Fitzpatrick SAMA analysis (Reference 15), the cost of providing additional DC battery capacity is estimated to be $500,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $250,000.

8.8 120 VAC Power Events The contribution to risk from the 120 VAC inverters is caused by test and maintenance unavailability of the inverters. Two ways of eliminating the maintenance unavailability were investigated. The first is to provide a separate 120 VAC regulating transformer that would bypass the existing inverters when powering the 120 VAC bus. This alternative would provide continuous power for scenarios where offsite power remains available but is lost but the EDGs repower the emergency AC buses. Power would be lost for station blackout scenarios. The second method is to provide a spare inverter that would replace 8-5 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification the out of service inverter through temporary connections. The spare inverter would be moved to the affected bus and connected as needed. This alternative would, ensure that 120 VAC power is available for all scenarios until station 125 VDC batteries are depleted.

Fitzpatrick SAMA analysis (Reference 15), estimated the cost of DC bus cross-ties to be

$300,000. Connections similar to those for bus cross-ties would be needed to allow for connection of a spare inverter. The cost of spare inverter is not included in the above costs so the cost of implementation is expected to be much greater.

8.9 AC Power Events SAMDA items for the AC power system relate to two types of improvements, station auxiliary transformers (SATs) and operation of 4kVAC circuit breakers. Each of these two types is described below.

8.9.1 SAT Events The contribution to risk from the SATs is caused by test and maintenance unavailability of the transformers. To compensate for that unavailability, a redundant means of providing AC power would be required. Addition of a transformer large enough to supply required loads along with the associated buses and breakers would be expected to cost several million dollars. Even neglecting engineering costs, such a plant change is estimated to cost at least $3,000,000.

8.9.2 4.16KV Circuit Breaker Events The contribution of circuit breaker failure to risk involves failure of power supply breakers to close when needed and load shed circuit breakers to open when required. To compensate for failure of circuit breakers to open when needed requires that the cause of the fault be cleared and that the load be stripped by some other means. Because such failures must be cleared quickly, it is considered impractical that any changes could be made to compensate for such failures.

Failure of power supply breaker to close could be mitigated by providing an inter-bus cross-tie which would allow one bus on a division to supply power to the other bus on that division. Implementation of this alternative would require an additional breaker on each of the two buses on each division.

8-6 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The Susquehanna SAMA (Reference 16) estimated the cost of 4kV bus cross-ties to be

$656,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $328,000.

8.10 POSRV Events Failure to depressurize the RCS when needed contributes to risk by causing failure of feed and bleed cooling. Addition of one more POSRV would provide additional relief capacity thereby minimizing the impact of any single POSRV failure.

The Callaway SAMA analysis (Reference 14) estimated the cost for adding a new PORV at

$500,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $250,000.

8.11 Chiller/Cooler Events Failure to provide cooling to the pump rooms and emergency diesel rooms can result in failure of the components due to high temperatures. Addition of a redundant train of ventilation could prevent failure of a single chiller or room cooler from resulting in failure of the affected equipment pumps or diesel generator.

As shown in the Vermont Yankee SAMA (Reference 11), the estimated cost to implement a redundant train or means of ventilation is $2,202,725. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $1,100,000.

8.12 Safety Injection System Events SAMDA items for the safety injection system relate to three types of improvements, pumps, IRWST strainers, and a manual recirculation valve. Each of these three types is described below.

8.12.1 Safety Injection Pump Events Mitigation of safety injection pump failures requires an additional means of providing flow through the safety injection system. The simplest method of implementation would be to add an additional safety injection pump that could be aligned to either division of safety injection using the existing piping and valves.

8-7 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The Callaway SAMA analysis (Reference 14) estimated the cost of replacing two safety injection pumps to be greater than $1,000,000. The cost for a single pump would be greater than $500,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $500,000.

8.12.2 IRWST Strainer Recent initiatives to improve reliability of ECCS strainers have been implemented throughout the US nuclear industry. These changes have cost several million dollars per plant. Costs to improve the IRWST strainer performance for the APR1400 would be similar in cost to these projects. Therefore, the cost to improve performance of IRWST strainers is taken to be at least $1,000,000 8.12.3 Safety Injection Recirculation Valve Failure of a single manual valve could cause minimum flow recirculation to fail for two pumps on a division. Addition of a separate flow path for each pump would prevent such failures. To implement this option, two additional manual valves and lines would be needed.

Brunswick SAMA 27 (Reference 13) estimates the cost of a service water cross-tie modification to be $100,000. This modification would involve one valve and minimal piping. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $50,000 for a single valve or $100,000 for two valves and lines.

8.13 ESW Events SAMDA items for the ESW system relate to three types of improvements, pumps, cooling towers, and return valve. Each of these three types is described below.

8.13.1 ESW Filter Events Mitigation of common cause failure of ESW filters failure requires that an additional means of providing flow through the ESW system if the in-service filters plug. For this item, the simplest means of implementation would be to be to provide an additional ESW filter that could be aligned to either division of ESW given plugging of the in-service filters.

Because the filter would need to be placed in-serice rapidly, remotely-operated valves would be required. For this item, only the costs of the additional pump and driver are 8-8 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification estimated. Costs for the switchgear, circuit breakers, and any valves need to operate the pump are neglected.

Brunswick SAMA 27 (Reference 13) estimated the cost of a service water cross-tie modification to be $100,000. This modification would involve one valve and minimal piping. Providing an additional filter would be more complex. However, costs of

$100,000 are used as the minimum potential implementation costs.

8.13.2 ESW Pump Events Mitigation of ESW pump failure requires that an additional means of providing flow through the ESW system. For this item, the simplest means of implementation would be to be to provide an additional ESW pump that could be aligned to either division of ESW thereby using much of the existing piping. For this item, only the costs of the additional pump and driver are estimated. Costs for the switchgear, circuit breakers, and any valves need to operate the pump are neglected.

The Callaway SAMA analysis (Reference 14) estimated the cost of adding an additional service water pump to be $5,000,000. Assuming engineering and procedure updates make up 50% of the cost, addition of a spare ESW pump would cost at least $2,500,000.

8.13.3 ESW Cooling Towers Addition of a redundant cooling tower would require additional valves, piping and a cooling tower structure. Two remotely operated valves are estimated to cost at least

$100,000. This cost alone exceeds the potential benefit estimated previously. Therefore, neglecting thee tower structure, piping, and instrumentation, addition of a redundant ESW cooling tower would cost at least $100,000.

8.13.4 ESW Cooling Tower Return Valve ESW flow to the standby cooling tower requires that an automatic valve open to allow flow to the tower. For these scenarios, several hours would be available from the time that the need for flow has been identified until heat removal is needed. During this time, manual actions to compensate for failure of the valves could take place.

Addition of a manual valve to provide a bypass around each of the four automatic return valves would allow operator action to compensate for failure of the motor-operated isolation valves.

8-9 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Brunswick SAMA 27 (Reference 13) estimated the cost of a service water cross-tie modification to be $100,000. This modification would involve similar piping and valve installation as required for the ESW bypass valves but would provide for only one valve, not four as would be needed to fully implement the SAMDA on each of the four cooling towers. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $50,000 for each of the four towers.

8.14 ECW Pumps Mitigation of ECW pump failure requires that an additional means of providing flow through the ECW system. For this item, the simplest means of implementation would be to be to provide an additional ECW pump that could be aligned to either division of ECW thereby using much of the existing piping. For this item, only the costs of the additional pump and driver are estimated. Costs for the switchgear, circuit breakers, and any valves need to operate the pump are neglected.

The Callaway SAMA analysis (Reference 14) estimates the cost of adding an additional CCW pump to cost $1,000,000. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $500,000. While a CCW pump is much larger than would be required for an ECW pump, the costs for CCW provide insight into the costs of an ECW pump. Assuming that an ECW pump costs half of a CCW pump, the costs of a spare ECW pump would be about $250,000 neglecting costs for circuit breakers, controls, piping and valves.

8.15 SCRAM Due To Mechanical Failure Events The benefit for eliminating mechanical scram failures is calculated to be only Basic events for SCRAM failure caused by mechanical failures are present in only $38,900. It is considered incredible that any change could be made to the reactor core and associated structures for less than that amount. Therefore, no specific cost estimates are performed.

8.16 Control Software Events Mitigation of control software failures would require addition of a redundant and diverse control system for key plant equipment in addition to the three methods in the current design. Providing an additional diverse and redundant control system is estimated to cost at least $1,000,000 when considering the additional circuits, panels, and displays needed.

8-10 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 8.17 Main Steam Events SAMDA items for the main steam system relate to three types of improvements, ADVs, MSIVs, and MSSVs. Each of these three types is described below.

8.17.1 ADVs Mitigation of ADV failure requires that an additional means of removing steam from a steam generator be provided. Removal of steam requires that the valve allow cooling to atmospheric pressure. For this item, the simplest means of implementation would be to be to provide an additional ADV for each steam generator.

The Callaway SAMA analysis (Reference 14) estimated the cost for adding a new PORV to be $500,000. Such a valve would be similar in design and function to an ADV. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $250,000.

8.17.2 MSIVs Elimination of common cause failure of MSIVs to close would require an additional means to isolate the main steam lines. Considering the minimum costs above for a simple manual valve on the service water system, $50,000, costs of four valves would be $200,000.

Valves that could function at main steam pressures would cost substantially more.

8.17.3 MSSVs Mitigation of the common cause MSSV failure to open failure requires that a diverse means of relieving steam be provided.

The Callaway SAMA analysis (Reference 14) estimated the cost for adding a new PORV to be $500,000. Such a valve would be similar in design and function to an ADV. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $250,000.

8.18 TGBCCW Pump The cost of a TGBCCW pump would be similar to the cost for an ECW pump estimated in Section 8.13 or $250,000.

8-11 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 8.19 Shutdown Cooling System Pumps Mitigation of SDC pump failure requires that an additional means of providing flow through the SDC spray system. The APR1400 PRA model credits the containment spray pumps as a means of providing SDC flow. Therefore, an additional means of providing SDC flow must be provided. For this item, the simplest means of implementation would be to be to provide an additional SDC pump that could be aligned to either division of thereby using much of the existing piping.

The Callaway SAMA analysis (Reference 14) estimated the cost for implementing a redundant containment spray system as $2,000,000. Such a change would be similar in scope to providing a redundant SDC pump and, therefore, the costs are considered representative. Assuming engineering and procedure updates make up 50% of the cost, such a change would cost at least $1,000,000.

8-12 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9 SAMDA COST-BENEFIT EVALUATION For each of the potential SAMDAs discussed in Section 7, a cost-benefit evaluation is performed. Equation 1 of Section 4.0 defines the present worth of averted public risk by implementing a plant enhancement as:

NPV = (APE + AOC + AOE + AOSC) - COE.

Total averted costs (TAC) are represented by the expression:

TAC = (APE + AOC + AOE + AOSC).

Each of the terms is defined in Sections 4.1, 4.2, 4.3, and 4.4 respectively.

For each of the potential SAMDAs evaluated, total averted costs are developed and documented in Section 7. Cost estimates that can be used to screen each of the potential SAMDAs were developed and documented in Section 8. Using those values a cost-benefit analysis is performed for each of the potential SAMDAs.

An enhancement is considered beneficial if the present worth is positive.

9.1 Emergency Diesel Generator Events As quantified in Section 7.1.5 and 7.1.6, the total benefit of eliminating any EDG-related failures was $295,000. From Section 8.1, implementation of this alternative would cost a minimum of $900,000. Therefore, the present worth can be calculated as:

NPV = $295,000 - $900,000.

NPV = (-)$605,000.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.2 AAC Combustion Turbine Generator Events As quantified in Section 7.2, the total benefit of eliminating any AAC CTG-related failures was $125,600. As discussed in Section 8.2, the costs for SAMDA items related to the AAC CTG would be similar to those for the EDG presented above. Therefore, the present worth can be calculated as:

9-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification NPV = $125,600 - $900,000.

NPV = (-)$774,400.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.3 Auxiliary Feedwater Events 9.3.1 AFW Isolation Valve Events As quantified in Section 7.3.8, the total benefit of eliminating any AFW isolation valve-related failures was $158,900. From Section 8.3.1, implementation of this alternative would cost a minimum of $350,000. Therefore, the present worth can be calculated as:

NPV = $158,900 - $350,000.

NPV = (-)$191,100.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.3.2 AFW Pumps As quantified in Section 7.3.9 and 7.3.10, the total benefit of eliminating any AFW pump-related failures was $166,800. From Section 8.3.2, implementation of this alternative would cost a minimum of $6,000,000. Therefore, the present worth can be calculated as:

NPV = $166,800 - $6,000,000.

NPV = (-)$5,833,200.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.3.3 Startup FW Pump PP07 Events As quantified in Section 7.3.7, the total benefit of eliminating any startup FW pump-related failures was $37,900. From Section 8.3.2, implementation of this alternative would cost a minimum of $6,000,000. Therefore, the present worth can be calculated as:

NPV = $37,900 - $6,000,000.

NPV = (-)$5,962,100.

9-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.4 Fire Barrier Failure Events As quantified in Section 7.4.1, the total benefit of eliminating any fire barrier-related failures was $58,000. From Section 8.4, implementation of this alternative would cost a minimum of $350,000. Therefore, the present worth can be calculated as:

NPV = $58,000 - $350,000.

NPV = (-)$292,000.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.5 Component Cooling Water (CCW) Events 9.5.1 DG001A CCW Inlet Valve MOV-191 As quantified in Section 7.5.5, the total benefit of eliminating any DG inlet valve-related failure was $8,500. Costs to implement an improvement for this item would be similar or more than calculated in Section 8.5.2 or a minimum of $50,000. Therefore, the present worth can be calculated as:

NPV = $8,500 - $50,000.

NPV = (-)$41,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.5.2 CCW Pumps As quantified in Section 7.5.6, the total benefit of eliminating any CCW pump-related failure was $87,500. From Section 8.5.1, implementation of this alternative would cost a minimum of $500,000. Therefore, the present worth can be calculated as:

NPV = $87,500 - $500,000.

NPV = (-)$412,500.

9-3 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.5.3 CS Heat Exchanger Isolation Valves As quantified in Section 7.5.7, the total benefit of eliminating any CS heat exchanger CCW isolation valve-related failure was $40,500. From Section 8.5.2, implementation of this alternative would cost a minimum of $50,000. Therefore, the present worth can be calculated as:

NPV = $40,500 - $50,000.

NPV = (-)$9,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.6 Containment Spray (CS) Events 9.6.1 Containment Spray Pumps As quantified in Section 7.6.7, the total benefit of eliminating any CS pump-related failure was $68,900. From Section 8.6.1, implementation of this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $68,900 - $1,000,000.

NPV = (-)$931,100.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.6.2 Total Containment Spray Isolation Valve Event Summary As quantified in Section 7.6.8, the total benefit of eliminating any CS header isolation valve-related failure was $38,300. From Section 8.6.2, implementation of this alternative would cost a minimum of $50,000. Therefore, the present worth can be calculated as:

NPV = $38,300 - $50,000.

NPV = (-)$11,700.

9-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.6.3 Containment Spray Heat Exchangers As quantified in Section 7.6.9, the total benefit of eliminating any CS pump-related failure was $39,300. From Section 8.6.3, implementation of this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $39,300 - $1,000,000.

NPV = (-)$960,700.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.7 125 VDC Power Events As quantified in Section 7.7.5, the total benefit of eliminating any battery-related failure was $101,200. From Section 8.7, implementation of this alternative would cost a minimum of $250,000. Therefore, the present worth can be calculated as:

NPV = $101,200 - $250,000.

NPV = (-)$148,800.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.8 120 VAC Power Events As quantified in Section 7.8.5, the total benefit of eliminating any 120 VAC inverter-related failure was $106,900. From Section 8.8, implementation of this alternative would cost a minimum of $300,000. Therefore, the present worth can be calculated as:

NPV = $106,900 - $300,000.

NPV = (-)$193,100.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-5 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.9 AC Power Events 9.9.1 SAT Transformers As quantified in Section 7.9.10, the total benefit of eliminating any SAT-related failure was

$55,000. From Section 8.9.1, implementation of this alternative would cost a minimum of

$3,000,000. Therefore, the present worth can be calculated as:

NPV = $55,000 - $3,000,000.

NPV = (-)$2,945,000.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.9.2 4.16KV Circuit Breakers As quantified in Section 7.9.11, the total benefit of eliminating any 4kV breaker-related failure was $187,500. From Section 8.9.2, implementation of this alternative would cost a minimum of $328,000. Therefore, the present worth can be calculated as:

NPV = $187,500 - $328,000.

NPV = (-)$140,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.10 POSRVs As quantified in Section 7.10.5, the total benefit of eliminating any POSRV-related failure was $68,100. From Section 8.9.2, implementation of this alternative would cost a minimum of $328,000. Therefore, the present worth can be calculated as:

NPV = $68.100 - $250,000.

NPV = (-)$181,900.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-6 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.11 Chiller/Cooler Events 9.11.1 ECW Chiller Summary As quantified in Section 7.11.16, the total benefit of eliminating any chiller-related failure was $201,600. From Section 8.11, implementation of this alternative would cost a minimum of $1,100,000. Therefore, the present worth can be calculated as:

NPV = $201,600 - $1,100,000.

NPV = (-)$898,400.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.11.2 EDG Room Cubical Coolers As quantified in Section 7.11.17, the total benefit of eliminating any chiller-related failure was $110,700. From Section 8.11, implementation of this alternative would cost a minimum of $1,100,000. Therefore, the present worth can be calculated as:

NPV = $110,700 - $1,100,000.

NPV = (-)$989,300.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.11.3 Motor Driven AFW Pump Room Cubical Coolers As quantified in Section 7.11.18, the total benefit of eliminating any chiller-related failure was $114,500. From Section 8.11, implementation of this alternative would cost a minimum of $1,100,000. Therefore, the present worth can be calculated as:

NPV = $114,500 - $1,100,000.

NPV = (-)$985,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-7 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.11.4 Air Handling Units As quantified in Section 7.11.19, the total benefit of eliminating any air handling unit-related failure was $35,100. From Section 8.11, implementation of this alternative would cost a minimum of $1,100,000. Therefore, the present worth can be calculated as:

NPV = $35,100 - $1,100,000.

NPV = (-)$1,064,900.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.12 Safety Injection (SI) Events 9.12.1 SI Pumps PP02D Events As quantified in Section 7.12.5, the total benefit of eliminating any SI pump-related failure was $87,100. From Section 8.12.1, implementation of this alternative would cost a minimum of $500,000. Therefore, the present worth can be calculated as:

NPV = $87,100 - $500,000.

NPV = (-)$412,900.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.12.2 IRWST Strainer Events As quantified in Section 7.12.6, the total benefit of eliminating any IRWST strainer-related failure was $72,800. From Section 8.12.2, implementation of this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $72,800 - $1,000,000.

NPV = (-)$927,200.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-8 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.12.3 SI Valve V-959 Events As quantified in Section 7.12.7, the total benefit of eliminating any SI pump recirculation valve-related failure was $38,700. From Section 8.12.3, implementation of this alternative would cost a minimum of $50,000. Therefore, the present worth can be calculated as:

NPV = $38,700 - $50,000.

NPV = (-)$11,300.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.13 ESW Events The generic SAMDA items evaluated for the APR1400 design related to the ESW system are listed in Table 5 and include items 42 and 47.

9.13.1 ESW Filter Plugging Events As quantified in Section 7.13.3, the total benefit of eliminating any ESW filter plugging-related failure was $89,800. From Section 8.13.1, implementation of this alternative would cost a minimum of $100,000. Therefore, the present worth can be calculated as:

NPV = $89,800 - $100,000.

NPV = (-)$10,200.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.13.2 ESW HOV-074 As quantified in Section 7.13.8, the total benefit of eliminating any ESW return valve-related failure was $8,400. From Section 8.13.4, implementation of this alternative would cost a minimum of $200,000. Therefore, the present worth can be calculated as:

NPV = $8,400 - $200,000.

NPV = (-)$191,600.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-9 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.13.3 ESW Pumps As quantified in Section 7.13.9, the total benefit of eliminating any ESW pump-related failure was $121,500. From Section 8.13.2, implementation of this alternative would cost a minimum of $2,500,000. Therefore, the present worth can be calculated as:

NPV = $121,500 - $2,500,000.

NPV = (-)$2,378,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.13.4 Total ESW Cooling Tower Events Summary As quantified in Section 7.13.10, the total benefit of eliminating any ESW cooling tower-related failure was $74,000. From Section 8.13.3, implementation of this alternative would cost a minimum of $100,000. Therefore, the present worth can be calculated as:

NPV = $74,000 - $100,000.

NPV = (-)$26,000.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.14 ECW Pumps As quantified in Section 7.14.3, the total benefit of eliminating any ECW pump-related failure was $94,300. From Section 8.14, implementation of this alternative would cost a minimum of $250,000. Therefore, the present worth can be calculated as:

NPV = $94,300 - $250,000.

NPV = (-)$155,700.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-10 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 9.15 SCRAM Due To Mechanical Failure As discussed in Section 8.15, the costs to improve the mechanical scram system are considered much greater than the potential benefit and no specific costs are estimated.

However, improvements are considered to show a negative cost-benefit.

9.16 Control Software 9.16.1 PPS Loop Controller Application Software As quantified in Section 7.16.1, the total benefit of eliminating any loop controller application software-related failure was $125,300. From Section 8.16, implementation of this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $125,300 - $1,000,000.

NPV = (-)$874,700.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.16.2 PPS Group Controller Application Software As quantified in Section 7.16.2, the total benefit of eliminating any group controller application software-related failure was $37,500. From Section 8.16, implementation of this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $37,500 - $1,000,000.

NPV = (-)$962,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.16.3 PPS Loop Controller Operating System Software As quantified in Section 7.16.3, the total benefit of eliminating any PPS loop controller application software-related failure was $59,500. From Section 8.16, implementation of 9-11 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $59,500 - $1,000,000.

NPV = (-)$940,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.17 Main Steam Events 9.17.1 Main Steam Atmospheric Dump Valve (V-102)

As quantified in Section 7.17.1, the total benefit of eliminating any MS ADV-related failure was $45,800. From Section 8.17.1, implementation of this alternative would cost a minimum of $250,000. Therefore, the present worth can be calculated as:

NPV = $48,500 - $250,000.

NPV = (-)$201,500.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.17.2 Main Steam Isolation Valves As quantified in Section 7.17.2, the total benefit of eliminating any MSIV-related failure was $40,900. From Section 8.17.2, implementation of this alternative would cost a minimum of $200,000. Therefore, the present worth can be calculated as:

NPV = $40,900 - $200,000.

NPV = (-)$159,100.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.17.3 Main Steam Safety Valves As quantified in Section 7.17.3, the total benefit of eliminating any MSSV-related failure was $40,600. From Section 8.17.3, implementation of this alternative would cost a minimum of $250,000. Therefore, the present worth can be calculated as:

9-12 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification NPV = $40,600 - $250,000.

NPV = (-)$209,400.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.18 TGBCCW Events 9.18.1 TGBCCW Pump Train 2 Events As quantified in Section 7.18, the total benefit of eliminating any TGBCCW pump-related failure was $37,300. From Section 8.18, implementation of this alternative would cost a minimum of $250,000. Therefore, the present worth can be calculated as:

NPV = $37,300 - $250,000.

NPV = (-)$212,700.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9.19 Shutdown Cooling System (SDC) Events 9.19.1 SDC Pumps As quantified in Section 7.19.3, the total benefit of eliminating any SDC pump-related failure was $71,600. From Section 8.19, implementation of this alternative would cost a minimum of $1,000,000. Therefore, the present worth can be calculated as:

NPV = $71,600 - $1,000,000.

NPV = (-)$928,400.

Since the present worth is negative, implementation of a SAMDA for this item would not be cost beneficial.

9-13 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10 SENSITIVITY ANALYSIS (THREE-PERCENT DISCOUNT RATE)

The parameters that influence the cost-benefit analyses of the SAMDA evaluations were examined to determine if a change in value for one of the parameters would change the conclusions of the evaluation. Equations for each of the four types of averted costs contain a term for the real discount rate and evaluation period (see Sections 4.1 to 4.4) where each contain a term for the real discount rate and evaluation period. Therefore, a change in either of those terms would have a direct impact on the averted costs calculated.

NEI 05-01 (Reference 1) recommends using a 7 percent discount rate for cost-benefit analyses and suggests that a 3 percent discount rate should be used for sensitivity analyses on the maximum benefit and the unscreened SAMDAs to indicate the sensitivity of the results to the choice of discount rate. This sensitivity case is discussed below.

The methodology of Reference 1 determines the present worth net value of public risk according to the following formula:

NPV = (APE + AOC + AOE + AOSC) - COE (14)

Where NPV = present value of current risk ($),

APE = present value of averted public exposure ($),

AOC = present value of averted offsite property damage costs ($),

AOE = present value of averted occupational exposure ($),

AOSC = present value of averted onsite costs ($),

COE = cost of any enhancement implemented to reduce risk ($).

The derivation of each of these costs is described in the subsections below. All equations used in the subsections below are taken from Reference 2 which is the basis for the equations given in Reference 1.

The following specific values were used for various terms in the analyses:

Present Worth The present worth was determined by:

PW = [1 e(rt) ]r (15) 10-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

Where, r is the discount rate = 3% per year (assumed throughout these analyses) t is the years remaining until end of plant life = 60 years PW is the present worth of a string of annual payments of one dollar = $27.823 Dollars per REM The conversion factor used for assigning a monetary value to on-site and off-site exposures was $2,000/person-rem averted. This is consistent with the NRCs regulatory analysis guidelines presented in and used throughout Reference 1.

10.1 Averted Public Exposure (APE)

Expected offsite doses from the internal events PRA accident sequences are presented in Tables 2a through 2f. Costs associated with these doses were calculated using the following equation:

APE = ( ) x x [1 e(rtf ) ]r (16)

Where APE = present value of averted public exposure ($),

R = monetary equivalent of unit dose, ($2000/person-rem),

FS = baseline accident frequency (events per year from Tables 3a through 3f),

FA = accident frequency after mitigation (0 events per year),

FSDPS = baseline accident offsite frequency (person-rem per year from Tables 3a through 3f),

FADPA = accident offsite dose frequency after mitigation (0 person-rem per year),

r = real discount rate (3% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, APE is calculated for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events. Each of these calculations is detailed below.

10-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.1.1 APE for At-Power Internal Events APE(IE) = (5.33x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.03x60)) / (0.03 per year))

= $29,659 10.1.2 APE for At-Power Internal Flooding Events APE(Fld) = (5,51x10-2 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.03x60)) / (0.03 per year))

= $3,066 10.1.3 APE for At-Power Internal Fire Events APE(Fire) = (5.79x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e - (0.03x60)) / (0.03 per year))

= $32,219 10.1.4 APE for LPSD Internal Events APE(SDIE) = (3.34x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.03x60)) / (0.03 per year))

= $18,586 10.1.5 APE for LPSD Flooding Events APE(SDFld) = (1.40x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.03x60)) / (0.03 per year))

= $7,802 10.1.6 APE for LPSD Fire Events APE(SDFire)= (1.31x10-1 person-rem per year - 0) x ($2000/person-rem) x ((1 - e- (0.03x60)) / (0.03 per year))

= $7,290 10-3 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.1.7 Total APE APETot = APE(IE) + APE(Fld) + APE(Fire) + APE(SDIE) + APE(SDFld) + APE(SDFire)

= $29,659 + $3,066 + $32,219 + $18,586 + $7,802 + $7,290

= $98,622 10.2 Averted Public Offsite Property Damage Costs (AOC)

Annual expected offsite economic risk is shown in Tables 4a through 4f. The costs associated with AOC were calculated using the following equation:

AOC = ( ) x [1 e(rtf ) ]r (17)

Where, AOC = present value of averted offsite property damage costs ($),

FSDDS = baseline accident frequency x property damage (cost per year from Tables 4a through 4f),

FADDA = accident frequency x property damage after mitigation (0 event per year),

r = real discount rate (3% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, AOC is calculated for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events. Each of these calculations is detailed below.

10.2.1 AOC for At-Power Internal Events AOC(IE) = ($1,534 per year - 0) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $42,671 10.2.2 AOC for At-Power Internal Flooding Events AOC(Fld) = ($142 per year - 0) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $3,938 10-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.2.3 AOC for At-Power Internal Fire Events AOC(Fire) = ($1,355 per year - 0) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $37,707 10.2.4 AOC for LPSD Internal Events AOC(SDIE) = ($883 per year - 0) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $24,563 10.2.5 AOC for LPSD Flooding Events AOC(SDFld)= ($314 per year - 0) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $8,746 10.2.6 AOC for LPSD Fire Events AOC(SDFire)= ($316 per year - 0) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $8,792 10.2.7 Total AOC AOCTot = AOC(IE) + AOC(Fld) + AOC(Fire) + AOC(SDIE) + AOC(SDFld) + AOC(SDFire)

= $42,671 + $3,938 + $37,707 + $24,563 + $8,746 + $8,792

= $126,417 10.3 Averted Occupational Exposure (AOE)

There are two types of occupational exposure due to accidents: immediate and long-term.

Immediate exposure occurs at the time of the accident and during the immediate management of the emergency. Long-term exposure is associated with the cleanup and refurbishment or decommissioning of the damaged facility. The value of avoiding both types of exposure must be considered when evaluating risk.

10-5 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification The occupational exposure associated with severe accidents was assumed to be 23,300 person-rem/accident. This value includes a short-term component of 3,300 person-rem/accident and a long-term component of 20,000 person-rem/accident. These estimates are consistent with the best estimate values presented in Reference 2. In calculating base risk, the accident-related onsite exposures were calculated using the best estimate exposure components applied over the on-site cleanup period. For onsite cleanup, the accident-related on-site exposures were calculated over a 10-year cleanup period. Costs associated with immediate dose, long-term dose and total dose are calculated below for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events.

10.3.1 Averted Immediate Occupational Exposure Costs Per the guidance of Reference 1, costs associated with immediate occupational doses from an accident were calculated using the following equation:

= ( ) x x [1 e(rtf ) ]r (18)

Where, WIO = present value of averted immediate occupational exposure ($),

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

DIOS = baseline expected immediate onsite dose (3300 person-rem/event),

DIOA = expected occupational exposure after mitigation (3300 person-rem/event),

R = monetary equivalent of unit dose, ($2000/person-rem),

r = real discount rate (3% per year),

tf = years remaining until end of plant life (60 years).

Using the values given above, WIO is calculated for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events. Each of these calculations is detailed below.

10.3.1.1 WIO for At-Power Internal Events WIO(IE) = ((1.00x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.03 x 60)) / (0.03 per year) 10-6 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

= $184 10.3.1.2 WIO for At-Power Internal Flooding Events WIO (Fld) = ((3.82x10-7 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $70 10.3.1.3 WIO for At-Power Internal Fire Events WIO (Fire) = ((2.79x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $512 10.3.1.4 WIO for LPSD Internal Events WIO (SDIE) = ((1.94x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $356 10.3.1.5 WIO for LPSD Flooding Events WIO (SDFld) = ((8.06x10-8 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $15 10.3.1.6 WIO for LPSD Fire Events WIO (SDFire)= ((1.48x10-6 events per year) x (3300 person-rem/event) - 0) x ($2000/person-rem) x (1 - e - (0.03 x 60)) / (0.03 per year)

= $272 10.3.2 Averted Long-Term Occupational Exposure Costs Per the guidance of Reference 1, costs associated with long-term occupational doses from an accident were calculated using the following equation:

10-7 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

= ( ) x x [1 e(rtf ) ]r x [1 e(rm) ]r (19)

Where, WLTO = present value of averted long-term occupational exposure ($),

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

DLTOS = baseline expected long-term onsite dose (20,000 person-rem/event),

DLTOA = expected occupational exposure after mitigation (20,000 person-rem/event),

R = monetary equivalent of unit dose, ($2000/person-rem),

r = real discount rate (3% per year),

m = years over which long-term doses accrue (10 years from Reference 2),

tf = years remaining until end of plant life (60 years).

Using the values given above, WLTO is calculated for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events. Each of these calculations is detailed below.

10.3.2.1 WLTO for At-Power Internal Events WLTO(IE) = ((1.00x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.03 x 60)) / (0.03 per year) x ((1 - e - (0.03 x 10)) / ((0.03 per year) x (10 years))

= $962 10.3.2.2 WLTO for At-Power Internal Flooding Events WLTO (Fld) = ((3.82x10-7 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.03 x 60)) / (0.03 per year) x ((1 - e - (0.03 x 10)) / ((0.03 per year) x (10 years))

= $367 10-8 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.3.2.3 WLTO for At-Power Internal Fire Events WLTO (Fire) = ((2.79x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.03 x 60)) / (0.03 per year) x ((1 - e - (0.03 x 10)) / ((0.03 per year) x (10 years))

= $2,683 10.3.2.4 WLTO for LPSD Internal Events WLTO (SDIE)= ((1.94x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e- (0.03 x 60)) / (0.03 per year) x ((1 - e- (0.03 x 10)) / ((0.03 per year) x (10 years))

= $1,865 10.3.2.5 WLTO for LPSD Flooding Events WLTO (SDFld)= ((8.06x10-8 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e - (0.03 x 60)) / (0.03 per year) x ((1 - e - (0.03 x 10)) / ((0.03 per year) x (10 years))

= $78 10.3.2.6 WLTO for LPSD Fire Events WLTO(SDFire)= ((1.48x10-6 events per year) x (20,000 person-rem/event) - 0) x ($2000/person-rem) x ((1 - e- (0.03 x 60)) / (0.03 per year) x ((1 - e- (0.03 x 10)) / ((0.03 per year) x (10 years))

= $1,423 10.3.3 Total Averted Occupational Exposure Costs As described in Section 4.3.3, the total cost associated with averted occupational exposure, AOE, is the sum of the costs associated with averted immediate exposure and the costs associated with the averted long-term exposure, or:

AOE = WIO + WLTO (20) 10-9 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Total averted onsite exposure costs are calculated below.

10.3.3.1 AOE for At-Power Internal Events AOE(IE) = $ 184 + $ 962 = $1,146 10.3.3.2 AOE for At-Power Internal Flooding Events AOE (Fld) = $ 70 + $ 367 = $437 10.3.3.3 AOE for At-Power Internal Fire Events AOE (Fire) = $ 512 + $ 2,683 = $3,195 10.3.3.4 AOE for LPSD Internal Events AOE(SDIE) = $ 356 + $ 1,865 = $2,221 10.3.3.5 AOE for LPSD Flooding Events AOE(SDFld)= $ 15 + $ 78 = $93 10.3.3.6 AOE for LPSD Fire Events AOE(SDFire)= $ 272 + $ 1,423 = $1,695 10.3.3.7 Total AOE Total averted occupational exposure costs are the sum of the four individual costs calculated above or:

AOE Tot = AOE(IE) + AOE(Fld) + AOE(Fire) + AOE(SDIE) + AOE(SDFld) + AOE(SDFire)

= $1,146 + $437 + $3,195 + $2,221 + $93 + $1,695

= $8,787 10.4 Averted Onsite Costs (AOSC)

Reference 2 defines three types of costs associated with onsite property damage from an accident: cleanup and decontamination, long-term replacement power, and repair and refurbishment. The value of avoiding each of these types of costs must be considered when 10-10 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification evaluating risk. Total averted onsite property damage costs are the sum of the three types of costs. Calculation of onsite property damage costs is detailed in the sections that follow.

10.4.1 Averted Cleanup and Decontamination Costs The estimated cleanup cost for severe accidents was defined in Reference 2, to be $1. x109

/accident (undiscounted). Using the value of $1.5x109 /event and assuming, as in Reference 2, that the total sum is paid in equal installments over a ten year period, the present value of those ten payments for cleanup and decontamination costs for the cleanup period can be calculated as follows:

PVCD = CCD /m x { 1 e(rm) r} (21)

Where, PVCD = net present value of cleanup and decontamination for a single event (dollars)

CCD = total undiscounted cost for single accident with constant year basis (dollars) r = real discount rate (3% per year),

m = years over which long-term doses accrue (10 years)

PVCD = (($1.5x109 /event) / (10 years)) x ((1 - e - (0.03 x 10)) / 0.03)

= $1.2959 x 109 The present value of the costs over the cleanup period must be considered over the period of plant life. The net present value of averted cleanup costs over the plant life can be calculated using the following equation:

UCD = ( ) x PVCD x [1 e(rtf ) ]r (22)

Where, UCD = present value of averted onsite cleanup costs (dollars)

FS = baseline accident frequency (events per year from Tables 1a and 1b),

FA = accident frequency after mitigation (0 events per year),

r = real discount rate (3% per year),

tf = years remaining until end of plant life (60 years).

10-11 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Using the values given above, UCD is calculated for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events. Each of these calculations is detailed below.

10.4.1.1 UCD for At-Power Internal Events UCD(IE) = (1.00x10-6 events per year - 0) x ($1.2959x109) x (1 - e - (0.03 x 60))

/ (0.03 per year)

= $36,056 10.4.1.2 UCD for At-Power Internal Flooding Events UCD (Fld) = (3.82x10-7 events per year - 0) x ($1.2959x109) x (1 - e - (0.03 x 60))

/ (0.03 per year)

= $13,773 10.4.1.3 UCD for At-Power Internal Fire Events UCD (Fire) = (2.79x10-6 events per year - 0) x ($1.2959x109) x (1 - e - (0.03 x 60))

/ (0.03 per year)

= $100,596 10.4.1.4 UCD for LPSD Internal Events UCD (SDIE) = (1.94x10-6 events per year - 0) x ($1.2959x109) x (1 - e - (0.03 x 60))

/ (0.03 per year)

= $69,948 10.4.1.5 UCD for LPSD Flooding Events UCD(SDFld) = (8.06x10-8 events per year - 0) x ($1.2959x109) x (1 - e - (0.03 x 60))

/ (0.03 per year)

= $2,906 10-12 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.4.1.6 UCD for LPSD Fire Events UCD(SDFire) = (1.48x10-6 events per year - 0) x ($1.2959x109) x (1 - e - (0.03 x 60))

/ (0.03 per year)

= $53,363 10.4.2 Averted Replacement Power Costs Calculation of replacement power costs, however, requires a change in the equation in Section 4.4.2. Instead of using the equations shown in Section 4.4.2 to calculate URP, Reference 2 recommends using a linear interpolation between $1.9x1010 for a discount rate of one percent and 1.2x1010 for a discount rate of five percent. These values are based on a 24 year average remaining life and need to be adjusted to be applicable to the APR1400 design. The averted replacement power cost (URP) was adjusted for the average reactor years remaining. The replacement power cost must also be adjusted to 2013 dollars and again for the more realistic capacity factor of 95%. As detailed in Section 4.4.2, two multiplies are added to account for these adjustments:

2016 Dollars Scaling Factor Multiplier: 1.57 95% Capacity Factor Multiplier: 1.58 For this 3% discounted rate sensitivity case, the URP was adjusted to average reactor years remaining:

60 year / 24 year plant life: 2.50 These multipliers are applied to equations documented in Sections 10.4.2.1 through 10.4.2.6.

Replacement power costs are calculated as detailed below.

10.4.2.1 URP for At-Power Internal Events URP(IE) = {$1.9x1010 - [($1.9x1010 - 1.2x1010) / (1% - 5%)] x (1% - 3%)}

x (1400 MWe / 910 MWe) x (1.00x10-6 events per year - 0) x (1.57) x (1.58) x (2.50)

= $147,883 10-13 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.4.2.2 URP for At-Power Internal Flooding Events URP (Fld) = {$1.9x1010 - [($1.9x1010 - 1.2x1010)/(1% - 5%)] x (1% - 3%)}

x (1400 MWe / 910 MWe) x (3.82x10-7 events per year - 0) x (1.57) x (1.58) x (2.50)

= $56,490 10.4.2.3 URP for At-Power Internal Fire Events URP (Fire) = {$1.9x1010 - [($1.9x1010 - 1.2x1010)/(1% - 5%)] x (1% - 3%)}

x (1400 MWe / 910 MWe) x (2.79x10-6 events per year - 0) x (1.57) x (1.58) x (2.50)

= $412,590 10.4.2.4 URP for LPSD Internal Events URP (SDIE) = {$1.9x1010 - [($1.9x1010 - 1.2x1010)/(1% - 5%)] x (1% - 3%)}

x (1400 MWe/910 MWe) x (1.94x10-6 events per year - 0) x (1.57) x (1.58) x (2.50)

= $286,890 10.4.2.5 URP for LPSD Flooding Events URP (SDFld) = {$1.9x1010 - [($1.9x1010 - 1.2x1010)/(1% - 5%)]x(1% - 3%)}

x (1400 MWe/910 MWe) x (8.06x10-8 events per year - 0) x (1.57) x (1.58) x (2.50)

= $11,920 10.4.2.6 URP for LPSD Fire Events URP (SDFire) = {$1.9x1010 - [($1.9x1010 - 1.2x1010)/(1% - 5%)]x(1% - 3%)}

x (1400 MWe/910 MWe) x (1.48x10-6 events per year - 0) x (1.57) x (1.58) x (2.50)

= $218,865 10-14 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.4.3 Averted Repair and Refurbishment Costs It is assumed that the plant would not be repaired or refurbished; therefore, these costs are zero.

10.4.4 Total Averted Onsite Costs (AOSC)

Total averted onsite cost is the sum of cleanup and decontamination costs, replacement power costs, and the repair and refurbishment costs. Total averted onsite costs are calculated as follows:

AOSC = UCD +URP + 0 (23)

Total averted onsite costs are calculated for At-Power internal events, internal flooding events, and fires, along with LPSD internal events, internal flooding events, and fires events. Each of these calculations is detailed below.

10.4.4.1 AOSC for At-Power Internal Events AOSC(IE) = $36,056 + $147,883

= $183,939 10.4.4.2 AOSC for At-Power Internal Flooding Events AOSC (Fld)= $13,773 + $56,490

= $70,263 10.4.4.3 AOSC for At-Power Internal Fire Events AOSC (Fire)= $100,596 + $412,590

= $513,186 10.4.4.4 AOSC for LPSD Internal Events AOSC(SDIE)= $69,948 + $286,890

= $356,838 10-15 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 10.4.4.5 AOSC for LPSD Flooding Events AOSC(SDFld)=$2,906 + $11,920

= $14,826 10.4.4.6 AOSC for LPSD Fire Events AOSC(SDFire)=$53,363 + $218,865

= $272,228 10.4.4.7 Total AOSC AOSC Tot = AOSC(IE) + AOSC(Fld) + AOSC(Fire) + AOSC(SDIE) + AOSC(SDFld)

+ AOSC(SDFire)

= $183,939 + $70,263 + $513,186 + $356,838 + $14,826 + $272,228

= $1,411,280 10.5 Cost Enhancement (COE)

The cost of enhancement is used when measures are taken to reduce risk. By definition, such measures are taken at the beginning of any period considered, so no discounting is performed for the COE. For baseline risk, no measures have been taken to reduce risk, so:

COE = $0 10.6 Total Unmitigated Baseline Risk As described in Section 10, the total present worth net value of public risk is calculated according to the following formula:

NPV = (APE + AOC + AOE + AOSC) - COE (24)

Using the values calculated in Sections 10.1 to 10.5, total baseline risk is calculated:

NPV = ($98,622 + $126,417 + $8,787 + $1,411,280) - $0

= $1,645,106 10-16 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification This value can be viewed as the maximum risk benefit attainable if all core damage scenarios from internal events are eliminated over the 60-year plant life.

10-17 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 11 CONCLUSIONS The analyses described in the Sections 4 through 9 analyzed the base case for the cost-benefit analyses at a 7% discounted rate along with the benefit associated with important contributors to risk for the APR1400 plant design. Preliminary screening eliminated SAMDA candidates from further consideration, based on inapplicability to APR1400 design features, design features that have already been incorporated into the APR1400 design, or extremely high cost of the alternatives considered.

The analysis using a 7 percent discount rate showed that no design changes to reduce risk associated with contributors to plant risk would be cost-beneficial to implement. A second baseline maximum benefit calculation using a 3 percent discount rate showed an approximate $736,000 increase in the calculated benefits if all core damage scenarios from internal events are eliminated over the 60-year plant life. Therefore, it is concluded that no design changes would provide a positive cost-benefit.

11-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification 12 REFERENCES

1. NEI 05-01, Severe Accident Mitigation Alternatives (SAMA) Analysis - Guidance Document, Rev. A, Nuclear Energy Institute, November 2005.

2. NUREG/BR-0184, Regulatory Analysis Technical Evaluation Handbook, U.S.

Nuclear Regulatory Commission, 1997.

3. APR1400-E-P-NR-14006-P, Severe Accident Mitigation Design Alternatives (SAMDAs) for APR1400, Rev. 2, KEPCO & KHNP, August 2018.

4. NUREG-1555, Standard Review Plans for Environmental Reviews for Nuclear Power Plants: Environmental Standard Review Plan, Section 7.3, Severe Accident Mitigation Alternatives, Rev. 1, U.S. Nuclear Regulatory Commission, July 2007.

5. Not Used.

6. Bureau of Labor Statistics Producer Price Index for the commodity of Electric Power (BLS 2016l Producer Price Index-Commodities: Series Id: WPU054 Electric Powerl 2016/1993), Year 2016 Annual PPI, https://www.bls.gov/data/

7. Not Used.

8. APR1400-K-X-FS-14002-P, Tier 2, Chapter 19, Probabilistic Risk Assessment and Severe Accident Evaluation, Rev. 3, KEPCO & KHNP, August 2018.

9. Not Used.

10. Palo Verde Nuclear Generating Station, Applicants Environmental Report; Operating License Renewal Stage, Supplement 1, April 10, 2009

11. Vermont Yankee Nuclear Power Station, Applicants Environmental Report, Operating License Renewal Stage, Attachment E - Severe Accident Mitigation Alternatives Analysis.

12. Millstone Power Station, Units 2 and 3, Application for Renewed Operating Licenses, Appendix F MPS2 Severe Accident Mitigation Alternatives Analysis.

13. Brunswick Steam Electric Plant, License Renewal Application, Environmental Report, Appendix F Severe Accident Mitigation Alternatives.

12-1 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification

14. Callaway Plant Unit 1, Environmental Report for License Renewal, Appendix F Severe Accident Mitigation Alternatives.

15. James A. FitzPatrick Nuclear Power Plant, Applicant's Environmental Report, Operating License Renewal Stage, Appendix E Severe Accident Mitigation Alternatives.

16. Susquehanna Steam Electric Station Units 1 & 2, License Renewal Application, Environmental Report, Appendix E Severe Accident Mitigation Alternatives.

12-2 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 1a (1 of 1)

Base Case - Source Term Category Summary for At-Power Events STC Frequency (per year)

STC Description Internal Flood Fire 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 7.13E-08 2.32E-09 2.59E-08 2 SGTR bypass of containment with fission product scrubbing 3.79E-08 0.00E+00 0.00E+00 3 ISLOCAs without fission product scrubbing 5.31E-11 0.00E+00 0.00E+00 4 ISLOCAs with fission product scrubbing 6.49E-11 0.00E+00 0.00E+00 5 Containment isolation failure with containment spray (CS) 1.82E-09 4.39E-09 1.15E-08 6 Containment isolation failure without CS 8.73E-10 2.95E-09 6.22E-08 7 Containment failure before core damage with small (leak) failure of containment 7.51E-09 2.47E-09 6.61E-09 8 Containment failure before core damage with large (rupture failure of containment 8.24E-09 2.84E-09 7.37E-09 9 Core melt arrested in the reactor vessel 5.43E-07 1.76E-07 5.36E-07 10 No containment failure after core melt 2.90E-07 1.52E-07 1.92E-06 11 Containment basemat failure 1.94E-08 2.50E-08 1.14E-07 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 0.00E+00 13 Early containment failure with large (rupture) failure of containment 5.20E-10 1.87E-10 6.42E-08 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 5.14E-11 6.87E-11 2.73E-10 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 0.00E+00 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 7.31E-12 3.82E-12 2.73E-11 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 9.01E-09 5.78E-09 1.57E-08 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 5.53E-10 8.29E-10 3.34E-09 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 1.63E-09 9.96E-10 2.11E-09 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.68E-11 1.15E-11 1.25E-10 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 1.17E-08 6.38E-09 2.36E-08 Total 1.00E-06 3.82E-07 2.79E-06 T-1 Rev. 1

APR1400 Applicants Environmental Report - Standard Design Certification Table 1b (1 of 1)

Base Case - Source Term Category Summary for Low Power Shutdown Events STC Frequency (per year)

STC Description Internal Flood Fire 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.89E-08 0.00E+00 3.74E-10 2 SGTR bypass of containment with fission product scrubbing 1.54E-08 0.00E+00 0.00E+00 3 ISLOCAs without fission product scrubbing 2.01E-09 0.00E+00 1.90E-09 4 ISLOCAs with fission product scrubbing 2.63E-11 0.00E+00 0.00E+00 5 Containment isolation failure with containment spray (CS) 7.38E-10 0.00E+00 1.66E-10 6 Containment isolation failure without CS 1.69E-08 8.06E-08 4.73E-08 7 Containment failure before core damage with small (leak) failure of containment 3.05E-09 0.00E+00 9.55E-11 8 Containment failure before core damage with large (rupture failure of containment 7.14E-09 0.00E+00 3.66E-10 9 Core melt arrested in the reactor vessel 2.20E-07 0.00E+00 7.74E-09 10 No containment failure after core melt 1.49E-06 0.00E+00 1.34E-06 11 Containment basemat failure 9.65E-08 0.00E+00 5.16E-08 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 0.00E+00 13 Early containment failure with large (rupture) failure of containment 2.11E-10 0.00E+00 9.28E-10 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 2.08E-11 0.00E+00 3.94E-12 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 0.00E+00 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 2.96E-12 0.00E+00 3.94E-13 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 3.65E-09 0.00E+00 2.27E-10 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 2.24E-10 0.00E+00 4.83E-11 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 6.61E-10 0.00E+00 3.05E-11 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 5.37E-08 0.00E+00 2.15E-08 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 4.74E-09 0.00E+00 3.41E-10 Total 1.94E-06 8.06E-08 1.48E-06 T-2 Rev. 1

APR1400 Applicants Environmental Report - Standard Design Certification Table 2 (1 of 1)

Representative Accident Sequences for each STC Frequency for Internal Events Percent Representative CET Sequence STC

(/ry) (%) (PDS)

SGTR CET-02 1 7.13E-08 7.1%

(PDS-02)

SGTR CET-01 2 3.79E-08 3.8%

(PDS-01)

ISLOCA CET-02 3 5.31E-11 0.0%

(PDS-03)

ISLOCA CET-01 4 6.49E-11 0.0%

(PDS-03)

CONISOF CET-01 5 1.82E-09 0.2%

(PDS-05)

CONISOF CET-02 6 8.73E-10 0.1%

(PDS-06)

RBCM CET-01 7 7.51E-09 0.7%

(PDS-07)

RBCM CET-02 8 8.24E-09 0.8%

(PDS-07)

GEN CET-04 9 5.43E-07 54.1 (PDS-04)

GEN CET-34 10 2.90E-07 28.9 (PDS-14)

GEN CET-41 11 1.94E-08 1.9%

(PDS 33) 12 - - -

GEN CET-05/07 13 5.20E-10 0.1 (PDS-14)

GEN CET-39 14 5.14E-11 0.0%

(PDS-33) 15 - - -

GEN CET-29 16 7.31E-12 0.0%

(PDS-33)

GEN CET-27/25 17 9.01E-09 0.9 (PDS-14)

GEN CET-40 18 5.53E-10 0.1 (PDS-33)

GEN CET-33/36 19 1.63E-09 0.2 (PDS-14)

GEN CET-30 20 1.68E-11 0.0%

(PDS-33)

GEN CET-26/28 21 1.17E-08 1.2 (PDS-14)

T-3 Rev. 1

APR1400 Applicants Environmental Report - Standard Design Certification Table 3a (1 of 1)

Offsite Exposure By Source Term Category for At-Power Internal Events Expected Pe STC Conditional Conditional rson-STC Description Frequency Person-Sv O Person-REM REM/yr Off (per year) ffsite Offsite site 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 7.13E-08 6.12E+04 6.12E+06 4.36E-01 2 SGTR bypass of containment with fission product scrubbing 3.79E-08 3.03E+02 3.03E+04 1.15E-03 3 ISLOCAs without fission product scrubbing 5.31E-11 9.16E+04 9.16E+06 4.86E-04 4 ISLOCAs with fission product scrubbing 6.49E-11 7.80E+04 7.80E+06 5.06E-04 5 Containment isolation failure with containment spray (CS) 1.82E-09 3.45E+03 3.45E+05 6.28E-04 6 Containment isolation failure without CS 8.73E-10 1.74E+04 1.74E+06 1.52E-03 7 Containment failure before core damage with small (leak) failure of containment 7.51E-09 4.35E+04 4.35E+06 3.27E-02 8 Containment failure before core damage with large (rupture failure of containment 8.24E-09 5.59E+04 5.59E+06 4.61E-02 9 Core melt arrested in the reactor vessel 5.43E-07 1.71E+01 1.71E+03 9.29E-04 10 No containment failure after core melt 2.90E-07 4.12E+01 4.12E+03 1.19E-03 11 Containment basemat failure 1.94E-08 1.87E+02 1.87E+04 3.63E-04 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 - -

13 Early containment failure with large (rupture) failure of containment 5.20E-10 3.22E+04 3.22E+06 1.67E-03 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of 14 5.14E-11 1.75E+03 1.75E+05 9.00E-06 containment Late containment failure with a wet cavity, CS operation, and a small (leak) failure of 15 0.00E+00 0.00E+00 - -

containment 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 7.31E-12 4.95E+03 4.95E+05 3.62E-06 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 9.01E-09 1.19E+02 1.19E+04 1.07E-04 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of 18 5.53E-10 2.84E+03 2.84E+05 1.57E-04 containment Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of 19 1.63E-09 4.30E+03 4.30E+05 7.01E-04 containment 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.68E-11 7.81E+03 7.81E+05 1.31E-05 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 1.17E-08 7.66E+03 7.66E+05 8.96E-03 Total 1.00E-06 5.33E-01 T-4 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 3b (1 of 1)

Offsite Exposure By Source Term Category for At-Power Internal Flooding Expected STC Conditional Conditional Person-STC Description Frequency Person-Sv Person-REM REM/yr (per year) Offsite Offsite Offsite 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.32E-09 6.12E+04 6.12E+06 1.42E-02 2 SGTR bypass of containment with fission product scrubbing 0.00E+00 3.03E+02 3.03E+04 0.00E+00 3 ISLOCAs without fission product scrubbing 0.00E+00 9.16E+04 9.16E+06 0.00E+00 4 ISLOCAs with fission product scrubbing 0.00E+00 7.80E+04 7.80E+06 0.00E+00 5 Containment isolation failure with containment spray (CS) 4.39E-09 3.45E+03 3.45E+05 1.51E-03 6 Containment isolation failure without CS 2.95E-09 1.74E+04 1.74E+06 5.13E-03 7 Containment failure before core damage with small (leak) failure of containment 2.47E-09 4.35E+04 4.35E+06 1.07E-02 8 Containment failure before core damage with large (rupture failure of containment 2.84E-09 5.59E+04 5.59E+06 1.59E-02 9 Core melt arrested in the reactor vessel 1.76E-07 1.71E+01 1.71E+03 3.01E-04 10 No containment failure after core melt 1.52E-07 4.12E+01 4.12E+03 6.26E-04 11 Containment basemat failure 2.50E-08 1.87E+02 1.87E+04 4.68E-04 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 - -

13 Early containment failure with large (rupture) failure of containment 1.87E-10 3.22E+04 3.22E+06 6.02E-04 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of 14 6.87E-11 1.75E+03 1.75E+05 1.20E-05 containment Late containment failure with a wet cavity, CS operation, and a small (leak) failure of 15 0.00E+00 0.00E+00 - -

containment 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 3.82E-12 4.95E+03 4.95E+05 1.89E-06 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 5.78E-09 1.19E+02 1.19E+04 6.88E-05 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of 18 8.29E-10 2.84E+03 2.84E+05 2.35E-04 containment Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of 19 9.96E-10 4.30E+03 4.30E+05 4.28E-04 containment 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.15E-11 7.81E+03 7.81E+05 8.98E-06 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 6.38E-09 7.66E+03 7.66E+05 4.89E-03 Total 3.82E-07 5.51E-02 T-5 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 3c (1 of 1)

Offsite Exposure By Source Term Category for At-Power Internal Fire Expected STC Conditional Conditional Person-STC Description Frequency Person-Sv Person-REM REM/yr (per year) Offsite Offsite Offsite 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.59E-08 6.12E+04 6.12E+06 1.59E-01 2 SGTR bypass of containment with fission product scrubbing 0.00E+00 3.03E+02 3.03E+04 0.00E+00 3 ISLOCAs without fission product scrubbing 0.00E+00 9.16E+04 9.16E+06 0.00E+00 4 ISLOCAs with fission product scrubbing 0.00E+00 7.80E+04 7.80E+06 0.00E+00 5 Containment isolation failure with containment spray (CS) 1.15E-08 3.45E+03 3.45E+05 3.97E-03 6 Containment isolation failure without CS 6.22E-08 1.74E+04 1.74E+06 1.08E-01 7 Containment failure before core damage with small (leak) failure of containment 6.61E-09 4.35E+04 4.35E+06 2.88E-02 8 Containment failure before core damage with large (rupture failure of containment 7.37E-09 5.59E+04 5.59E+06 4.12E-02 9 Core melt arrested in the reactor vessel 5.36E-07 1.71E+01 1.71E+03 9.17E-04 10 No containment failure after core melt 1.92E-06 4.12E+01 4.12E+03 7.91E-03 11 Containment basemat failure 1.14E-07 1.87E+02 1.87E+04 2.13E-03 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 - -

13 Early containment failure with large (rupture) failure of containment 6.42E-08 3.22E+04 3.22E+06 2.07E-01 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of 14 2.73E-10 1.75E+03 1.75E+05 4.78E-05 containment Late containment failure with a wet cavity, CS operation, and a small (leak) failure of 15 0.00E+00 0.00E+00 - -

containment 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 2.73E-11 4.95E+03 4.95E+05 1.35E-05 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 1.57E-08 1.19E+02 1.19E+04 1.87E-04 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of 18 3.34E-09 2.84E+03 2.84E+05 9.49E-04 containment Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of 19 2.11E-09 4.30E+03 4.30E+05 9.07E-04 containment 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.25E-10 7.81E+03 7.81E+05 9.76E-05 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 2.36E-08 7.66E+03 7.66E+05 1.81E-02 Total 2.79E-06 5.79E-01 T-6 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 3d (1 of 1)

Offsite Exposure By Source Term Category for Low Power Shutdown Internal Events Expected STC Conditional Conditional Person-STC Description Frequency Person-Sv Person-REM REM/yr (per year) Offsite Offsite Offsite 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.89E-08 6.12E+04 6.12E+06 1.77E-01 2 SGTR bypass of containment with fission product scrubbing 1.54E-08 3.03E+02 3.03E+04 4.66E-04 3 ISLOCAs without fission product scrubbing 2.01E-09 9.16E+04 9.16E+06 1.84E-02 4 ISLOCAs with fission product scrubbing 2.63E-11 7.80E+04 7.80E+06 2.05E-04 5 Containment isolation failure with containment spray (CS) 7.38E-10 3.45E+03 3.45E+05 2.55E-04 6 Containment isolation failure without CS 1.69E-08 1.74E+04 1.74E+06 2.93E-02 7 Containment failure before core damage with small (leak) failure of containment 3.05E-09 4.35E+04 4.35E+06 1.32E-02 8 Containment failure before core damage with large (rupture failure of containment 7.14E-09 5.59E+04 5.59E+06 3.99E-02 9 Core melt arrested in the reactor vessel 2.20E-07 1.71E+01 1.71E+03 3.76E-04 10 No containment failure after core melt 1.49E-06 4.12E+01 4.12E+03 6.13E-03 11 Containment basemat failure 9.65E-08 1.87E+02 1.87E+04 1.80E-03 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 - -

13 Early containment failure with large (rupture) failure of containment 2.11E-10 3.22E+04 3.22E+06 6.79E-04 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of 14 2.08E-11 1.75E+03 1.75E+05 3.65E-06 containment Late containment failure with a wet cavity, CS operation, and a small (leak) failure of 15 0.00E+00 0.00E+00 - -

containment 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 2.96E-12 4.95E+03 4.95E+05 1.47E-06 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 3.65E-09 1.19E+02 1.19E+04 4.35E-05 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of 18 2.24E-10 2.84E+03 2.84E+05 6.37E-05 containment Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of 19 6.61E-10 4.30E+03 4.30E+05 2.84E-04 containment 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 5.37E-08 7.81E+03 7.81E+05 4.19E-02 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 4.74E-09 7.66E+03 7.66E+05 3.63E-03 Total 1.94E-06 3.34E-01 T-7 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 3e (1 of 1)

Offsite Exposure By Source Term Category for Low Power Shutdown Internal Flooding Expected STC Conditional Conditional Person-STC Description Frequency Person-Sv Person-REM REM/yr (per year) Offsite Offsite Offsite 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 0.00E+00 - - -

2 SGTR bypass of containment with fission product scrubbing 0.00E+00 - - -

3 ISLOCAs without fission product scrubbing 0.00E+00 - - -

4 ISLOCAs with fission product scrubbing 0.00E+00 - - -

5 Containment isolation failure with containment spray (CS) 0.00E+00 - - -

6 Containment isolation failure without CS 8.06E-08 1.74E+04 1.74E+06 1.40E-01 7 Containment failure before core damage with small (leak) failure of containment 0.00E+00 - - -

8 Containment failure before core damage with large (rupture failure of containment 0.00E+00 - - -

9 Core melt arrested in the reactor vessel 0.00E+00 - - -

10 No containment failure after core melt 0.00E+00 - - -

11 Containment basemat failure 0.00E+00 - - -

12 Early containment failure with small (leak) failure of containment 0.00E+00 - - -

13 Early containment failure with large (rupture) failure of containment 0.00E+00 - - -

Late containment failure with a dry cavity, CS operation, and a small (leak) failure of 14 0.00E+00 - - -

containment Late containment failure with a wet cavity, CS operation, and a small (leak) failure of 15 0.00E+00 - - -

containment 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 0.00E+00 - - -

17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 0.00E+00 - - -

Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of 18 0.00E+00 - - -

containment Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of 19 0.00E+00 - - -

containment 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 0.00E+00 - - -

21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 0.00E+00 - - -

Total 8.06E-08 1.40E-01 T-8 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 3f (1 of 1)

Offsite Exposure By Source Term Category for Low Power Shutdown Internal Fire Expected STC Conditional Conditional Person-STC Description Frequency Person-Sv Person-REM REM/yr (per year) Offsite Offsite Offsite 1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 3.74E-10 6.12E+04 6.12E+06 2.29E-03 2 SGTR bypass of containment with fission product scrubbing 0.00E+00 3.03E+02 3.03E+04 0.00E+00 3 ISLOCAs without fission product scrubbing 1.90E-09 9.16E+04 9.16E+06 1.74E-02 4 ISLOCAs with fission product scrubbing 0.00E+00 7.80E+04 7.80E+06 0.00E+00 5 Containment isolation failure with containment spray (CS) 1.66E-10 3.45E+03 3.45E+05 5.73E-05 6 Containment isolation failure without CS 4.73E-08 1.74E+04 1.74E+06 8.24E-02 7 Containment failure before core damage with small (leak) failure of containment 9.55E-11 4.35E+04 4.35E+06 4.15E-04 8 Containment failure before core damage with large (rupture failure of containment 3.66E-10 5.59E+04 5.59E+06 2.05E-03 9 Core melt arrested in the reactor vessel 7.74E-09 1.71E+01 1.71E+03 1.32E-05 10 No containment failure after core melt 1.34E-06 4.12E+01 4.12E+03 5.53E-03 11 Containment basemat failure 5.16E-08 1.87E+02 1.87E+04 9.65E-04 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 - -

13 Early containment failure with large (rupture) failure of containment 9.28E-10 3.22E+04 3.22E+06 2.99E-03 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of 14 3.94E-12 1.75E+03 1.75E+05 6.90E-07 containment Late containment failure with a wet cavity, CS operation, and a small (leak) failure of 15 0.00E+00 0.00E+00 - -

containment 16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 3.94E-13 4.95E+03 4.95E+05 1.95E-07 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 2.27E-10 1.19E+02 1.19E+04 2.70E-06 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of 18 4.83E-11 2.84E+03 2.84E+05 1.37E-05 containment Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of 19 3.05E-11 4.30E+03 4.30E+05 1.31E-05 containment 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 2.15E-08 7.81E+03 7.81E+05 1.68E-02 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 3.41E-10 7.66E+03 7.66E+05 2.61E-04 Total 1.48E-06 1.31E-01 T-9 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4a (1 of 1)

Offsite Property Damage Costs By Source Term Category for At-Power Internal Events STC Conditional Expected STC Description Frequency Property Property (per year) Costs ($) Costs ($)

1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 7.13E-08 1.80E+10 1283 2 SGTR bypass of containment with fission product scrubbing 3.79E-08 5.26E+07 2 3 ISLOCAs without fission product scrubbing 5.31E-11 2.68E+10 1 4 ISLOCAs with fission product scrubbing 6.49E-11 2.02E+10 1 5 Containment isolation failure with containment spray (CS) 1.82E-09 3.91E+08 1 6 Containment isolation failure without CS 8.73E-10 3.90E+09 3 7 Containment failure before core damage with small (leak) failure of containment 7.51E-09 9.82E+09 74 8 Containment failure before core damage with large (rupture failure of 8.24E-09 1.51E+10 124 9 Core melt arrested in the reactor vessel 5.43E-07 3.50E+07 19 10 No containment failure after core melt 2.90E-07 3.32E+07 10 11 Containment basemat failure 1.94E-08 4.68E+07 1 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 -

13 Early containment failure with large (rupture) failure of containment 5.20E-10 5.55E+09 3 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 5.14E-11 6.19E+07 0 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 -

16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 7.31E-12 3.52E+08 0 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 9.01E-09 3.69E+07 0 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 5.53E-10 1.07E+08 0 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 1.63E-09 3.26E+08 1 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.68E-11 6.78E+08 0 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 1.17E-08 8.43E+08 10 Total 1534 T-10 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4b (1 of 1)

Offsite Property Damage Costs By Source Term Category for At-Power Internal Flooding STC Conditional Expected STC Description Frequency Property Property (per year) Costs ($) Costs ($)

1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.32E-09 1.80E+10 42 2 SGTR bypass of containment with fission product scrubbing 0.00E+00 5.26E+07 0 3 ISLOCAs without fission product scrubbing 0.00E+00 2.68E+10 0 4 ISLOCAs with fission product scrubbing 0.00E+00 2.02E+10 0 5 Containment isolation failure with containment spray (CS) 4.39E-09 3.91E+08 2 6 Containment isolation failure without CS 2.95E-09 3.90E+09 12 7 Containment failure before core damage with small (leak) failure of containment 2.47E-09 9.82E+09 24 8 Containment failure before core damage with large (rupture failure of 2.84E-09 1.51E+10 43 9 Core melt arrested in the reactor vessel 1.76E-07 3.50E+07 6 10 No containment failure after core melt 1.52E-07 3.32E+07 5 11 Containment basemat failure 2.50E-08 4.68E+07 1 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 -

13 Early containment failure with large (rupture) failure of containment 1.87E-10 5.55E+09 1 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 6.87E-11 6.19E+07 0 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 -

16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 3.82E-12 3.52E+08 0 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 5.78E-09 3.69E+07 0 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 8.29E-10 1.07E+08 0 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 9.96E-10 3.26E+08 0 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.15E-11 6.78E+08 0 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 6.38E-09 8.43E+08 5 Total 142 T-11 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4c (1 of 1)

Offsite Property Damage Costs By Source Term Category for At-Power Internal Fire STC Conditional Expected STC Description Frequency Property Property (per year) Costs ($) Costs ($)

1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.59E-08 1.80E+10 466 2 SGTR bypass of containment with fission product scrubbing 0.00E+00 5.26E+07 0 3 ISLOCAs without fission product scrubbing 0.00E+00 2.68E+10 0 4 ISLOCAs with fission product scrubbing 0.00E+00 2.02E+10 0 5 Containment isolation failure with containment spray (CS) 1.15E-08 3.91E+08 4 6 Containment isolation failure without CS 6.22E-08 3.90E+09 243 7 Containment failure before core damage with small (leak) failure of containment 6.61E-09 9.82E+09 65 8 Containment failure before core damage with large (rupture failure of 7.37E-09 1.51E+10 111 9 Core melt arrested in the reactor vessel 5.36E-07 3.50E+07 19 10 No containment failure after core melt 1.92E-06 3.32E+07 64 11 Containment basemat failure 1.14E-07 4.68E+07 5 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 -

13 Early containment failure with large (rupture) failure of containment 6.42E-08 5.55E+09 356 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 2.73E-10 6.19E+07 0 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 -

16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 2.73E-11 3.52E+08 0 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 1.57E-08 3.69E+07 1 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 3.34E-09 1.07E+08 0 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 2.11E-09 3.26E+08 1 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 1.25E-10 6.78E+08 0 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 2.36E-08 8.43E+08 20 Total 1355 T-12 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4d (1 of 1)

Offsite Property Damage Costs By Source Term Category for Low Power Shutdown Internal Events STC Conditional Expected STC Description Frequency Property Property (per year) Costs ($) Costs ($)

1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 2.89E-08 1.80E+10 520 2 SGTR bypass of containment with fission product scrubbing 1.54E-08 5.26E+07 1 3 ISLOCAs without fission product scrubbing 2.01E-09 2.68E+10 54 4 ISLOCAs with fission product scrubbing 2.63E-11 2.02E+10 1 5 Containment isolation failure with containment spray (CS) 7.38E-10 3.91E+08 0 6 Containment isolation failure without CS 1.69E-08 3.90E+09 66 7 Containment failure before core damage with small (leak) failure of containment 3.05E-09 9.82E+09 30 8 Containment failure before core damage with large (rupture failure of 7.14E-09 1.51E+10 108 9 Core melt arrested in the reactor vessel 2.20E-07 3.50E+07 8 10 No containment failure after core melt 1.49E-06 3.32E+07 49 11 Containment basemat failure 9.65E-08 4.68E+07 5 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 -

13 Early containment failure with large (rupture) failure of containment 2.11E-10 5.55E+09 1 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 2.08E-11 6.19E+07 0 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 -

16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 2.96E-12 3.52E+08 0 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 3.65E-09 3.69E+07 0 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 2.24E-10 1.07E+08 0 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 6.61E-10 3.26E+08 0 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 5.37E-08 6.78E+08 36 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 4.74E-09 8.43E+08 4 Total 883 T-13 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4e (1 of 1)

Offsite Property Damage Costs By Source Term Category for Low Power Shutdown Internal Flooding STC Conditional Expected STC Description Frequency Property Property (per year) Costs ($) Costs ($)

1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 0.00E+00 - -

2 SGTR bypass of containment with fission product scrubbing 0.00E+00 - -

3 ISLOCAs without fission product scrubbing 0.00E+00 - -

4 ISLOCAs with fission product scrubbing 0.00E+00 - -

5 Containment isolation failure with containment spray (CS) 0.00E+00 - -

6 Containment isolation failure without CS 8.06E-08 3.90E+09 314 7 Containment failure before core damage with small (leak) failure of containment 0.00E+00 - -

8 Containment failure before core damage with large (rupture failure of 0.00E+00 - -

9 Core melt arrested in the reactor vessel 0.00E+00 - -

10 No containment failure after core melt 0.00E+00 - -

11 Containment basemat failure 0.00E+00 - -

12 Early containment failure with small (leak) failure of containment 0.00E+00 - -

13 Early containment failure with large (rupture) failure of containment 0.00E+00 - -

14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 0.00E+00 - -

15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 - -

16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 0.00E+00 - -

17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 0.00E+00 - -

18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 0.00E+00 - -

19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 0.00E+00 - -

20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 0.00E+00 - -

21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 0.00E+00 - -

Total 314 T-14 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 4f (1 of 1)

Offsite Property Damage Costs By Source Term Category for Low Power Shutdown Internal Fire STC Conditional Expected STC Description Frequency Property Property (per year) Costs ($) Costs ($)

1 Steam generator tube rupture (SGTR) bypass of containment without fission product scrubbing 3.74E-10 1.80E+10 7 2 SGTR bypass of containment with fission product scrubbing 0.00E+00 5.26E+07 0 3 ISLOCAs without fission product scrubbing 1.90E-09 2.68E+10 51 4 ISLOCAs with fission product scrubbing 0.00E+00 2.02E+10 0 5 Containment isolation failure with containment spray (CS) 1.66E-10 3.91E+08 0 6 Containment isolation failure without CS 4.73E-08 3.90E+09 185 7 Containment failure before core damage with small (leak) failure of containment 9.55E-11 9.82E+09 1 8 Containment failure before core damage with large (rupture failure of 3.66E-10 1.51E+10 6 9 Core melt arrested in the reactor vessel 7.74E-09 3.50E+07 0 10 No containment failure after core melt 1.34E-06 3.32E+07 45 11 Containment basemat failure 5.16E-08 4.68E+07 2 12 Early containment failure with small (leak) failure of containment 0.00E+00 0.00E+00 -

13 Early containment failure with large (rupture) failure of containment 9.28E-10 5.55E+09 5 14 Late containment failure with a dry cavity, CS operation, and a small (leak) failure of containment 3.94E-12 6.19E+07 0 15 Late containment failure with a wet cavity, CS operation, and a small (leak) failure of containment 0.00E+00 0.00E+00 -

16 Late containment failure with a dry cavity, no CS, and a small (leak) failure of containment 3.94E-13 3.52E+08 0 17 Late containment failure with a wet cavity, no CS, and a small (leak) failure of containment 2.27E-10 3.69E+07 0 18 Late containment failure with a dry cavity, CS operation, and a large (rupture) failure of containment 4.83E-11 1.07E+08 0 19 Late containment failure with a wet cavity, CS operation, and a large (rupture) failure of containment 3.05E-11 3.26E+08 0 20 Late containment failure with a dry cavity, no CS, and a large (rupture) failure of containment 2.15E-08 6.78E+08 15 21 Late containment failure with a wet cavity, no CS, and large (rupture) failure of containment 3.41E-10 8.43E+08 0 Total 316 T-15 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (1 of 19)

Initial List of Candidate Improvements for the APR1400 SAMDA Analysis SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title)

Improvements Related to AC and DC Power 1 Provide additional DC battery +capacity. Extended DC power availability during an SBO. Sections 7.7, 8.7, and 9.7 evaluate the potential maximum benefit for 125 VDC power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

2 Replace lead-acid batteries with fuel cells Extended DC Power availability during an SBO Sections 7.7, 8.7, and 9.7 evaluate the potential maximum benefit for 125 VDC power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

3 Add additional battery charger or portable Improved availability of DC power system Sections 7.7, 8.7, and 9.7 evaluate the potential maximum diesel-driven battery charger to existing benefit for 125 VDC power events. A design change would DC system be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

5 Provide DC bus cross-ties. Improved availability of DC power system. Sections 7.7, 8.7, and 9.7 evaluate the potential maximum benefit for 125 VDC power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

6 Provide additional DC power to the Increased availability of the 120 V vital AC bus. Sections 7.8, 8.8, and 9.8 evaluate the potential maximum 120/240V vital AC system. benefit for 120V power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

7 Add an automatic feature to transfer the Increased availability of the 120 V vital AC bus. Sections 7.8, 8.8, and 9.8 evaluate the potential maximum 120V vital AC bus from normal to benefit for 120V power events. A design change would be standby power. expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

8 Increase training on response to loss of Improved chances of successful response to loss of N/A - Enhancement due to training is not applicable to the two 120V AC buses which causes two 120V AC buses. design certification stage of plant development SAMDA.

inadvertent actuation signals.

9 Provide an additional diesel generator. Increased availability of on-site emergency AC Sections 7.1, 8.1, and 9.1 evaluate the potential maximum power. benefit for EDG power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

T-16 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (2 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 10 Revise procedure to allow bypass of Extended diesel generator operation. N/A - Enhancement due to procedure revisions are not diesel generator trips. applicable to the design certification stage of plant development.

11 Improve 4.16-kV bus cross-tie ability. Increased availability of on-site AC power. N/A - Enhancement due to procedure revisions are not applicable to the design certification stage of plant development.

12 Create AC power cross-tie capability with Increased availability of on-site AC power. N/A - Enhancement due to procedure revisions are not other unit (multi-unit site) applicable to the design certification stage of plant development. Also, Design Certification does not consider duel unit capability 13 Install an additional, buried off-site power Reduced probability of loss of off-site power. N/A - This is a site-specific issue and not applicable to the source. design certification stage of plant development.

14 Install a gas turbine generator. Increased availability of on-site AC power. Already Implemented In Design. The alternate AC power source is a gas turbine generator.

15 Install tornado protection on gas turbine Increased availability of on-site AC power. Sections 7.2, 8.2, and 9.2 evaluate the potential maximum generator. benefit for CTG events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

16 Improve uninterruptible power supplies. Increased availability of power supplies supporting Sections 7.8, 8.8, and 9.8 evaluate the potential maximum front-line equipment. benefit for 120V power events. Sections 7.9, 8.9, and 9.9 evaluate the potential maximum benefit for 4.16kV power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

17 Create a cross-tie for diesel fuel oil Increased diesel generator availability. N/A - Design Certification does not consider duel unit (multiunit site). capability 18 Develop procedures for replenishing Increased diesel generator availability. N/A - Enhancement due to procedure revisions are not diesel fuel oil. applicable to the design certification stage of plant development.

19 Use fire water system as a backup source Increased diesel generator availability. Sections 7.1, 8.1, and 9.1 evaluate the potential maximum for diesel cooling. benefit for EDG power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

T-17 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (3 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 20 Add a new backup source of diesel Increased diesel generator availability. Sections 7.1, 8.1, and 9.1 evaluate the potential maximum cooling. benefit for EDG power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

21 Develop procedures to repair or replace Increased probability of recovery from failure of N/A - Enhancement due to procedure revisions are not failed 4 KV breakers. breakers that transfer 4.16 kV nonemergency buses applicable to the design certification stage of plant from unit station service transformers. development.

22 In training, emphasize steps in recovery Reduced human error probability during off-site N/A - Enhancement due to training is not applicable to the of off-site power after an SBO. power recovery. design certification stage of plant development SAMDA.

23 Develop a severe weather conditions Improved off-site power recovery following N/A - Enhancement due to procedure revisions are not procedure. external weather-related events. applicable to the design certification stage of plant development.

24 Bury off-site power lines. Improved off-site power reliability during severe N/A - This is a site-specific issue and not applicable to the weather. design certification stage of plant development.

Improvements Related to Core Cooling Systems 25 Install an independent active or passive Improved prevention of core melt sequences. Already Implemented In Design. The plant design has four high pressure injection system. trains of safety injection along with two charging pumps and an alternate charging pump.

26 Provide an additional high pressure Reduced frequency of core melt from small LOCA Sections 7.12, 8.12, and 9.12 evaluate the potential maximum injection pump with independent diesel. and SBO sequences. benefit for high-pressure injection events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

27 Revise procedure to allow operators to Extended HPCI and RCIC operation. N/A - Enhancement due to procedure revisions are not inhibit automatic vessel depressurization applicable to the design certification stage of plant in non-ATWS scenarios. development.

28 Add a diverse low pressure injection Improved injection capability. Already Implemented In Design. Plant design has two trains system. of SDC pumps that can be used for injection and two containment spray pumps that can be aligned to the SDC system for injection. Therefore, four pumps are available for low-pressure injection.

T-18 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (4 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 29 Provide capability for alternate injection Improved injection capability. Sections 7.1, 8.1, and 9.1 evaluate the potential maximum via diesel-driven fire pump. benefit for EDG power events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

Sections 7.12, 8.12, and 9.12 evaluate the potential maximum benefit for high-pressure injection events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

30 Improve ECCS suction strainers. Enhanced reliability of ECCS suction. Already Implemented In Design. Insights from GSI-191 considered in the APR1400 design, the strainers are designed to minimize a potential plugging, and the trash rack located at the ingress of the holdup volume tank (HVT) pre-screens any larger size debris entering the in-containment refueling water storage tank.

31 Add the ability to manually align Enhanced reliability of ECCS suction. Already Implemented In Design. The IRWST eliminates emergency core cooling system the need to switch to recirculation.

recirculation.

32 Add the ability to automatically align Enhanced reliability of ECCS suction. Already Implemented In Design. The IRWST eliminates emergency core cooling system to the need to switch to recirculation.

recirculation mode upon refueling water storage tank depletion.

33 Provide hardware and procedure to refill Extended reactor water storage tank capacity in the N/A - Enhancement due to procedure revisions are not the reactor water storage tank once it event of a steam generator tube rupture. applicable to the design certification stage of plant reaches a specified low level. development.

34 Provide an in-containment reactor water Continuous source of water to the safety injection Already Implemented In Design. The design includes an in-storage tank. pumps during a LOCA event, since water released containment reactor water storage tank from a breach of the primary system collects in the in-containment reactor water storage tank, and thereby eliminates the need to realign the safety injection pumps for long-term post-LOCA recirculation.

T-19 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (5 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 35 Throttle low pressure injection pumps Extended reactor water storage tank capacity. Already Implemented - The discharged water through the earlier in medium or large-break LOCAs break collects in the holdup volume tank (HVT) which is to maintain reactor water storage tank then transferred to the in-containment reactor water storage inventory. tank which eliminates the need to throttle low pressure injection pumps.

36 Emphasize timely recirculation alignment Reduced human error probability associated with N/A - Enhancement due to training is not applicable to the in operator training. recirculation failure. design certification stage of plant development SAMDA.

37 Upgrade the chemical and volume control For a plant like the Westinghouse AP600, where Sections 7.12, 8.12, and 9.12 evaluate the potential maximum system to mitigate small LOCAs. the chemical and volume control system cannot enefit for high-pressure injection events. A design change mitigate a small LOCA, an upgrade would decrease would be expected to cost more than any potential benefit the frequency of core damage. and, as a result, would not provide a positive benefit.

38 Change the in-containment reactor water Reduced common mode failure of injection paths. Sections 7.12, 8.12, and 9.12 evaluate the potential maximum storage tank suction from four check benefit for high-pressure injection events. A design change valves to two check and two air-operated would be expected to cost more than any potential benefit valves. and, as a result, would not provide a positive benefit.

39 Replace two of the four electric safety Reduced common cause failure of the safety Sections 7.12, 8.12, and 9.12evaluate the potential maximum injection pumps with diesel-powered injection system. This SAMA was originally benefit for high-pressure injection events. A design change pumps. intended for the Westinghouse-CE System 80+, would be expected to cost more than any potential benefit which has four trains of safety injection. However, and, as a result, would not provide a positive benefit.

the intent of this SAMA is to provide diversity within the high- and low-pressure safety injection systems.

40 Provide capability for remote, manual Improved chance of successful operation during N/A - Enhancement due to procedure revisions are not operation of secondary side pilot-operated station blackout events in which high area applicable to the design certification stage of plant relief valves in a station blackout. temperatures may be encountered (no ventilation to development.

main steam areas).

41 Create a reactor coolant depressurization Allows low pressure emergency core cooling Already Implemented In Design - Safety Depressurization system. system injection in the event of small LOCA and and Vent System (CDM 3.4.1) high-pressure safety injection failure.

42 Make procedure changes for reactor Allows low pressure emergency core cooling N/A - Enhancement due to procedure revisions are not coolant system depressurization. system injection in the event of small LOCA and applicable to the design certification stage of plant high-pressure safety injection failure. development.

T-20 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (6 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title)

Improvements Related to Cooling Water 43 Add redundant DC control power for SW Increased availability of SW. Sections 7.13, 8.13, and 9.13 evaluate the potential maximum pumps. benefit for ESW events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

44 Replace ECCS pump motors with air- Elimination of ECCS dependency on component Already Implemented / SI Pump Motors are air cooled by cooled motors. cooling system. room coolers 45 Enhance procedural guidance for use of Reduced frequency of loss of component cooling N/A - Enhancement due to procedure revisions are not cross-tied component cooling or service water and service water. applicable to the design certification stage of plant water pumps. development.

46 Add a service water pump. Increased availability of cooling water. Sections 7.13, 8.13, and 9.13 evaluate the potential maximum benefit for ESW events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

47 Enhance the screen wash system. Reduced potential for loss of SW due to clogging Sections 7.13, 8.13, and 9.13 evaluate the potential maximum of screens. benefit for ESW events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

48 Cap downstream piping of normally Reduced frequency of loss of component cooling Already Implemented - The design includes the caps for closed component cooling water drain water initiating events, some of which can be downstream piping of normally closed component cooling and vent valves. attributed to catastrophic failure of one of the many water drain and vent valves. See 1-461 series drawings.

single isolation valves.

49 Enhance loss of component cooling water Reduced potential for reactor coolant pump seal N/A - Enhancement due to procedure revisions are not (or loss of service water) procedures to damage due to pump bearing failure. applicable to the design certification stage of plant facilitate stopping the reactor coolant development.

pumps.

50 Enhance loss of component cooling water Reduced probability of reactor coolant pump seal N/A - Enhancement due to procedure revisions are not procedure to underscore the desirability failure. applicable to the design certification stage of plant of cooling down the reactor coolant development.

system prior to seal LOCA.

51 Additional training on loss of component Improved success of operator actions after a loss of N/A - Enhancement due to training is not applicable to the cooling water. component cooling water. design certification stage of plant development SAMDA.

T-21 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (7 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 52 Provide hardware connections to allow Reduced effect of loss of component cooling water N/A - 2 Charging Pumps are Air Cooled. Additional Aux another essential raw cooling water by providing a means to maintain the charging Charging Pump is a positive displacement type and requires system to cool charging pump seals. pump seal injection following a loss of normal no external cooling.

cooling water.

53 On loss of essential raw cooling water, Increased time before loss of component cooling N/A - Enhancement due to procedure revisions are not proceduralize shedding component water (and reactor coolant pump seal failure) applicable to the design certification stage of plant cooling water loads to extend the during loss of essential raw cooling water development.

component cooling water heat-up time. sequences.

54 Increase charging pump lube oil capacity. Increased time before charging pump failure due to Excessive Implementation Cost - Basic events related to lube oil overheating in loss of cooling water charging pump failure do not appear in the cutset importance sequences. analysis shown in Tables 6a through 6f or 7a through 7f.

Therefore, failure of a charging pump has minimal effect on plant risk and, as a result, negligible potential for improvement to risk.

55 Install an independent reactor coolant Reduced frequency of core damage from loss of Excessive Implementation Cost - Basic events related to pump seal injection system, with component cooling water, service water, or station RCP seal failure do not appear in the cutset importance dedicated diesel. blackout. analysis shown in Tables 6a through 6f or 7a through 7f.

Therefore, failure of a charging pump has minimal effect on plant risk and, as a result, negligible potential for improvement to risk.

56 Install an independent reactor coolant Reduced frequency of core damage from loss of Already implemented in design - an alternate charging pump pump seal injection system, without component cooling water or service water, but not a is provided that can be aligned for seal injection in the event dedicated diesel. station blackout. that the two normal charging pumps fail.

57 Use existing hydro test pump for reactor Reduced frequency of core damage from loss of N/A - Enhancement due to procedure revisions are not coolant pump seal injection. component cooling water or service water, but not a applicable to the design certification stage of plant station blackout. development.

58 Install improved reactor coolant pump Reduced likelihood of reactor coolant pump seal Already Implemented /The APR1400 will use advanced RCP seals. LOCA. seal design 59 Install an additional component cooling Reduced likelihood of loss of component cooling Sections 7.5, 8.5, and 9.5 evaluate the potential maximum water pump. water leading to a reactor coolant pump seal benefit for CCW events. A design change would be LOCA. expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

T-22 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (8 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 60 Prevent makeup pump flow diversion Reduced frequency of loss of reactor coolant pump Excessive Implementation Cost - Basic events related to through the relief valves. seal cooling if spurious high pressure injection RCP seal failure do not appear in the cutset importance relief valve opening creates a flow diversion large analysis shown in Tables 6a through 6f or 7a through 7f.

enough to prevent reactor coolant pump seal Therefore, failure of a charging pump has minimal effect on injection. plant risk and, as a result, negligible potential for improvement to risk.

61 Change procedures to isolate reactor Reduced frequency of core damage due to loss of N/A - Enhancement due to procedure revisions are not coolant pump seal return flow on loss of seal cooling. applicable to the design certification stage of plant component cooling water, and provide (or development.

enhance) guidance on loss of injection during seal LOCA.

62 Implement procedures to stagger high Extended high pressure injection prior to N/A - Enhancement due to procedure revisions are not pressure safety injection pump use after a overheating following a loss of service water. applicable to the design certification stage of plant loss of service water. development.

63 Use fire prevention system pumps as a Reduced frequency of reactor coolant pump seal Excessive Implementation Cost - Basic events related to backup seal injection and high pressure LOCA. RCP seal failure do not appear in the cutset importance makeup source. analysis shown in Tables 6a through 6f or 7a through 7f.

Therefore, failure of a charging pump has minimal effect on plant risk and, as a result, negligible potential for improvement to risk.

64 Implement procedure and hardware Improved ability to cool residual heat removal heat N/A - Enhancement due to procedure revisions are not modifications to allow manual alignment exchangers. applicable to the design certification stage of plant of the fire water system to the component development.

cooling water system, or install a component cooling water header cross-tie.

Improvements Related to Feedwater and Condensate 65 Install a digital feed water upgrade. Reduced chance of loss of main feed water Very Low Benefit following a plant trip.

66 Create ability for emergency connection Increased availability of feedwater. Sections 7.3, 8.3, and 9.3 evaluate the potential maximum of existing or new water sources to benefit for AFW events. A design change would be feedwater and condensate systems. expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

T-23 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (9 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 67 Install an independent diesel for the Extended inventory in CST during an SBO. Sections 7.3, 8.3, and 9.3 evaluate the potential maximum condensate storage tank makeup pumps. benefit for AFW events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

68 Add a motor-driven feedwater pump. Increased availability of feedwater. Already Implemented / APR1400 has 2 TDAFWP and 2 MDAFWP 69 Install manual isolation valves around Reduced dual turbine-driven pump maintenance Already Implemented / See 1-526 series P&IDs, manual auxiliary feedwater turbine-driven steam unavailability. valves installed up and downstream of Steam Inlet Stop admission valves. Valve (HP/LP) 70 Install accumulators for turbine-driven Eliminates the need for local manual action to align N/A - Steam Control Valves are Electro-Hydraulic operated auxiliary feedwater pump flow control nitrogen bottles for control air following a loss of valves. off-site power.

71 Install a new condensate storage tank Increased availability of the auxiliary feedwater Sections 7.3, 8.3, and 9.3 evaluate the potential maximum (auxiliary feedwater storage tank). system. benefit for AFW events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

72 Modify the turbine-driven auxiliary Improved success probability during a station Already Implemented / TDAFWPs are designed to operate in feedwater pump to be self-cooled. blackout. severe environments 73 Proceduralize local manual operation of Extended auxiliary feedwater availability during a N/A - Enhancement due to procedure revisions are not auxiliary feedwater system when control station blackout. Also provides a success path applicable to the design certification stage of plant power is lost. should auxiliary feedwater control power be lost in development.

non-station blackout sequences.

74 Provide hookup for portable generators to Extended auxiliary feedwater availability. Sections 7.7, 8.7, and 9.7 evaluate the potential maximum power the turbine-driven auxiliary benefit for 125 VDC power events. A design change would feedwater pump after station batteries are be expected to cost more than any potential benefit and, as a depleted. result, would not provide a positive benefit.

75 Use fire water system as a backup for Increased availability of steam generator water Sections 7.3, 8.3, and 9.3 evaluate the potential maximum steam generator inventory. supply. benefit for AFW events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

76 Change failure position of condenser Allows greater inventory for the auxiliary Already Implemented / Condensate Storage Tank Makeup to makeup valve if the condenser makeup feedwater pumps by preventing condensate storage Condenser AOVs Fail Closed (1-531 (1/5) P&ID) valve fails open on loss of air or power. tank flow diversion to the condenser.

T-24 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (10 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 77 Provide a passive, secondary-side heat Reduced potential for core damage due to loss-of- Sections 7.3, 8.3, and 9.3 evaluate the potential maximum rejection loop consisting of a condenser feedwater events. benefit for AFW events. A design change would be and heat sink. expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

78 Modify the startup feedwater pump so Increased reliability of decay heat removal. Sections 7.3, 8.3, and 9.3 evaluate the potential maximum that it can be used as a backup to the benefit for AFW events. A design change would be emergency feedwater system, including expected to cost more than any potential benefit and, as a during a station blackout scenario. result, would not provide a positive benefit.

79 Replace existing pilot-operated relief Increased probability of successful feed and bleed. Already Implemented / Success criteria for feed and bleed valves with larger ones, such that only cooling is 1 POSRV one is required for successful feed and bleed.

Improvements Related to Heating, Ventilation, and Air Conditioning 80 Provide a redundant train or means of Increased availability of components dependent on Sections 7.11, 8.11, and 9.11 evaluate the potential maximum ventilation. room cooling. benefit for HVAC events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

81 Add a diesel building high temperature Improved diagnosis of a loss of diesel building Sections 7.11, 8.11, and 9.11 evaluate the potential maximum alarm or redundant louver and thermostat. HVAC. benefit for HVAC events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

82 Stage backup fans in switchgear rooms. Increased availability of ventilation in the event of Sections 7.11, 8.11, and 9.11 evaluate the potential maximum a loss of switchgear ventilation. benefit for HVAC events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

83 Add a switchgear room high temperature Improved diagnosis of a loss of switchgear HVAC. Already implemented - The temperature switch is provided alarm. in the switchgear room. The cubicle cooler in the switchgear room operates automatically by the temperature switch to provide additional cooling as needed. The temperature in the switchgear room is indicated and high-high temperature is announced in the MCR and RSR.N/A - HVAC T-25 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (11 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 84 Create ability to switch emergency Continued fan operation in a station blackout. Already Implemented / TDAFWPs are designed to operate in feedwater room fan power supply to severe environments station batteries in a station blackout.

Improvements Related to Instrument Air and Nitrogen Supply 85 Provide cross-unit connection of Increased ability to vent containment using the N/A - The submitted design is a single-unit design and uninterruptible compressed air supply. hardened vent. enhancement due to a cross-unit connection is not a part of the design certification design.

86 Modify procedure to provide ability to Increased availability of instrument air after a N/A - Enhancement due to procedure revisions are not align diesel power to more air LOOP. applicable to the design certification stage of plant compressors. development.

87 Replace service and instrument air Elimination of instrument air system dependence Instrument air is a negligible contribution to plant risk.

compressors with more reliable on service water cooling. Therefore, any design change related to instrument air would compressors which have self-contained provide a negligible benefit.

air cooling by shaft driven fans.

88 Install nitrogen bottles as backup gas Extended SRV operation time. Not applicable - the APR1400 uses pilot operated safety supply for safety relief valves. relief valves that do not require air to operate.

89 Improve SRV and MSIV pneumatic Improved availability of SRVs and MSIVs. Sections 7.17, 8.17, and 9.17 evaluate the potential maximum components. benefit for main steam events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

Improvements Related to Containment Phenomena 90 Create a reactor cavity flooding system. Enhanced debris cool ability, reduced core concrete Already Implemented / Cavity Flooding System interaction, and increased fission product scrubbing.

91 Install a passive containment spray Improved containment spray capability. Implementation of this SAMDA does not affect CDF and system. would only cause a reduction in offsite risk costs, which limits potential benefit, or a maximum of $113,810.

In reality, the total maximum benefit would be much lower because all offsite consequences would not be eliminated.

Therefore, this design change would be expected to cost more than this amount and, as a result, not provide a positive benefit.

T-26 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (12 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 92 Use the fire water system as a backup Improved containment spray capability. Already Implemented / ESBCS.

source for the containment spray system.

93 Install an unfiltered, hardened Increased decay heat removal capability for non- Excessive Implementation Cost containment vent. ATWS events, without scrubbing released fission products.

94 Install a filtered containment vent to Increased decay heat removal capability for non- Excessive Implementation Cost remove decay heat Option 1: Gravel Bed ATWS events, with scrubbing of released fission Filter Option 2: Multiple Venturi products.

Scrubber 95 Enhance fire protection system and Improved fission product scrubbing in severe N/A - Enhancement due to procedure revisions are not standby gas treatment system hardware accidents. applicable to the design certification stage of plant and procedures. development.

96 Provide post-accident containment Reduced likelihood of hydrogen and carbon Excessive Implementation Cost inerting capability. monoxide gas combustion.

97 Create a large concrete crucible with heat Increased cooling and containment of molten core Excessive Implementation Cost removal potential to contain molten core debris. Molten core debris escaping from the vessel debris. is contained within the crucible and a water cooling mechanism cools the molten core in the crucible, preventing melt-through of the base mat.

98 Create a core melt source reduction Increased cooling and containment of molten core Excessive Implementation Cost system. debris. Refractory material would be placed underneath the reactor vessel such that a molten core falling on the material would melt and combine with the material. Subsequent spreading and heat removal from the vitrified compound would be facilitated, and concrete attack would not occur.

99 Strengthen primary/secondary Reduced probability of containment over- Excessive Implementation Cost containment (e.g., add ribbing to pressurization.

containment shell).

100 Increase depth of the concrete base mat or Reduced probability of base mat melt-through. Excessive Implementation Cost use an alternate concrete material to ensure melt-through does not occur.

T-27 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (13 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 101 Provide a reactor vessel exterior cooling Increased potential to cool a molten core before it Excessive Implementation Cost system. causes vessel failure, by submerging the lower head in water.

102 Construct a building to be connected to Reduced probability of containment over- Excessive Implementation Cost primary/secondary containment and pressurization.

maintained at a vacuum.

103 Institute simulator training for severe Improved arrest of core melt progress and N/A - Enhancement due to training is not applicable to the accident scenarios. prevention of containment failure. design certification stage of plant development SAMDA.

104 Improve leak detection procedures. Increased piping surveillance to identify leaks prior N/A - Enhancement due to procedure revisions are not to complete failure. Improved leak detection would applicable to the design certification stage of plant reduce LOCA frequency. development.

105 Delay containment spray actuation after a Extended reactor water storage tank availability. N/A - Enhancement due to procedure revisions are not large LOCA. applicable to the design certification stage of plant development.

106 Install automatic containment spray pump Extended time over which water remains in the Already Implemented / All ECCS pumps tanks suction from header throttle valves. reactor water storage tank, when full containment the IRWST spray flow is not needed.

107 Install a redundant containment spray Increased containment heat removal ability. Sections 7.6, 8.6, and 9.6 evaluate the potential maximum system. benefit for containment spray events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

108 Install an independent power supply to Reduced hydrogen detonation potential. Already Implemented / H2 Control System includes 2 the hydrogen control system using either redundant passive autocatalytic recombiners system.

new batteries, a non-safety grade portable generator, existing station batteries, or existing AC/DC independent power supplies, such as the security system diesel.

109 Install a passive hydrogen control system. Reduced hydrogen detonation potential. Already Implemented / H2 Control System includes 2 redundant passive autocatalytic recombiners system.

T-28 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (14 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 110 Erect a barrier that would provide Reduced probability of containment failure. Implementation of this SAMDA does not affect CDF and enhanced protection of the containment would only cause a reduction in offsite risk costs, which walls (shell) from ejected core debris limits potential benefit, or a maximum of $113,810.

following a core melt scenario at high In reality, the total maximum benefit would be much lower pressure. because all offsite consequences would not be eliminated.

Therefore, this design change would be expected to cost more than this amount and, as a result, not provide a positive benefit.

Improvements Related to Containment Bypass 111 Install additional pressure or leak Reduced ISLOCA frequency. Already implemented. Refer to 441-series P&ID.

monitoring instruments for detection of ISLOCAs.

112 Add redundant and diverse limit switches Reduced frequency of containment isolation failure Already implemented. Refer to 441-series P&ID.

to each containment isolation valve. and ISLOCAs.

113 Increase leak testing of valves in ISLOCA Reduced ISLOCA frequency. N/A - Enhancement due to procedure revisions are not paths. applicable to the design certification stage of plant development.

114 Install self-actuating containment Reduced frequency of isolation failure. Already Implemented / Containment Isolation System isolation valves. provides automatic and leak tight closure of those valves required to close for containment integrity 115 Locate residual heat removal (RHR) Reduced frequency of ISLOCA outside Excessive Implementation Cost inside containment containment.

116 Ensure ISLOCA releases are scrubbed. Scrubbed ISLOCA releases. Implementation of this SAMDA does not affect CDF and One method is to plug drains in potential would only cause a reduction in offsite risk costs, which break areas so that break point will be limits potential benefit, or a maximum of $113,810.

covered with water. In reality, the total maximum benefit would be much lower because all offsite consequences would not be eliminated.

Therefore, this design change would be expected to cost more than this amount and, as a result, not provide a positive benefit.

T-29 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (15 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 117 Revise EOPs to improve ISLOCA Increased likelihood that LOCAs outside N/A - Enhancement due to procedure revisions are not identification. containment are identified as such. A plant had a applicable to the design certification stage of plant scenario in which an RHR ISLOCA could direct development.

initial leakage back to the pressurizer relief tank, giving indication that the LOCA was inside containment.

118 Improve operator training on ISLOCA Decreased ISLOCA consequences. N/A - Enhancement due to training is not applicable to the coping. design certification stage of plant development SAMDA.

119 Institute a maintenance practice to Reduced frequency of steam generator tube Excessive Implementation Cost perform a 100% inspection of steam ruptures.

generator tubes during each refueling outage.

120 Replace steam generators with a new Reduced frequency of steam generator tube Excessive Implementation Cost design. ruptures.

121 Increase the pressure capacity of the Eliminates release pathway to the environment Excessive Implementation Cost secondary side so that a steam generator following a steam generator tube rupture.

tube rupture would not cause the relief valves to lift.

122 Install a spray system to depressurize the Enhanced depressurization capabilities during Excessive Implementation Cost primary system during a steam generator steam generator tube rupture.

tube rupture 123 Proceduralize use of pressurizer vent Backup method to using pressurizer sprays to N/A - Enhancement due to procedure revisions are not valves during steam generator tube reduce primary system pressure following a steam applicable to the design certification stage of plant rupture sequences. generator tube rupture. development.

124 Provide improved instrumentation to Improved mitigation of steam generator tube Already Implemented / H2 Control System includes 2 detect steam generator tube ruptures, such ruptures. redundant passive autocatalytic recombiners system.

as Nitrogen-16 monitors).

125 Route the discharge from the main steam Reduced consequences of a steam generator tube Already Implemented / See APR1400-CDM Table 3.8.2-2 safety valves through a structure where a rupture. #11 water spray would condense the steam and remove most of the fission products.

T-30 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (16 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 126 Install a highly reliable (closed loop) Reduced consequences of a steam generator tube Excessive Implementation Cost steam generator shell-side heat removal rupture.

system that relies on natural circulation and stored water sources 127 Revise emergency operating procedures Reduced consequences of a steam generator tube N/A - Enhancement due to procedure revisions are not to direct isolation of a faulted steam rupture. applicable to the design certification stage of plant generator. development.

128 Direct steam generator flooding after a Improved scrubbing of steam generator tube N/A - Enhancement due to procedure revisions are not steam generator tube rupture, prior to core rupture releases. applicable to the design certification stage of plant damage. development.

129 Vent main steam safety valves in Reduced consequences of a steam generator tube Excessive Implementation Cost containment. rupture.

Improvements Related to ATWS 130 Add an independent boron injection Improved availability of boron injection during Sections 7.15, 8.15, and 9.15 evaluate the potential maximum system. ATWS. benefit for ATWS events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

131 Add a system of relief valves to prevent Improved equipment availability after an ATWS. Sections 7.15, 8.15, and 9.15 evaluate the potential maximum equipment damage from pressure spikes benefit for ATWS events. A design change would be during an ATWS. expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

132 Provide an additional control system for Improved redundancy and reduced ATWS Sections 7.15, 8.15, and 9.15 evaluate the potential maximum rod insertion (e.g., AMSAC). frequency. benefit for ATWS events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

133 Install an ATWS sized filtered Increased ability to remove reactor heat from Excessive Implementation Cost containment vent to remove decay heat. ATWS events.

T-31 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (17 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 134 Revise procedure to bypass MSIV Affords operators more time to perform actions. N/A - Enhancement due to procedure revisions are not isolation in turbine trip ATWS scenarios. Discharge of a substantial fraction of steam to the applicable to the design certification stage of plant main condenser (i.e., as opposed to into the primary development.

containment) affords the operator more time to perform actions (e.g., SLC injection, lower water level, depressurize RPV) than if the main condenser was unavailable, resulting in lower human error probabilities.

135 Revise procedure to allow override of low Allows immediate control of low pressure core N/A - Enhancement due to procedure revisions are not pressure core injection during an ATWS injection. On failure of high pressure core injection applicable to the design certification stage of plant event. and condensate, some plants direct reactor development.

depressurization followed by five minutes of automatic low pressure core injection.

136 Install motor generator set trip breakers in Reduced frequency of core damage due to an Sections 7.15, 8.15, and 9.15 evaluate the potential maximum control room. ATWS. benefit for ATWS events. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

137 Provide capability to remove power from Decreased time required to insert control rods if the N/A - Enhancement due to procedure revisions are not the bus powering the control rods. reactor trip breakers fail (during a loss of feedwater applicable to the design certification stage of plant ATWS which has rapid pressure excursion). development.

Improvements Related to Internal Flooding 138 Improve inspection of rubber expansion Reduced frequency of internal flooding due to N/A - Enhancement due to procedure revisions are not joints on main condenser. failure of circulating water system expansion joints. applicable to the design certification stage of plant development.

139 Modify swing direction of doors Prevents flood propagation. N/A - This item relates to a specific vulnerability at one separating turbine building basement station.

from areas containing safeguards equipment.

Improvements to Reduce Seismic Risk 140 Increase seismic ruggedness of plant Increased availability of necessary plant equipment Seismic risk is considered negligible to the APR1400 plant components. during and after seismic events. design.

141 Provide additional restraints for CO2 Increased availability of fire protection given a Seismic risk is considered negligible to the APR1400 plant tanks. seismic event. design.

T-32 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (18 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title)

Improvements to Reduce Fire Risk 142 Replace mercury switches in fire Decreased probability of spurious fire suppression N/A - No mercury switches are identified in the APR1400 protection system. system actuation. design.

143 Upgrade fire compartment barriers. Decreased consequences of a fire. Sections 7.4, 8.4, and 9.4 evaluate the potential maximum benefit for fire barriers. A design change would be expected to cost more than any potential benefit and, as a result, would not provide a positive benefit.

144 Install additional transfer and isolation Reduced number of spurious actuations during a Implementation of this SAMDA would only affect fire risk switches. fire. (at-power and LPSD) which limits potential benefit, or a maximum of $486,000. Because multiple switches would need to be added, the potential costs are considered excessive.

145 Enhance fire brigade awareness. Decreased consequences of a fire. N/A - Enhancement due to procedures/training are not applicable to the design certification stage of plant development.

146 Enhance control of combustibles and Decreased fire frequency and consequences. N/A - Enhancement due to procedures/training are not ignition sources. applicable to the design certification stage of plant development.

Other Improvements 147 Install digital large break LOCA Reduced probability of a large break LOCA (a leak Large break LOCAs are a negligible contribution to plant protection system. before break). risk. Therefore, any design change related to instrument air would provide a negligible benefit.

148 Enhance procedures to mitigate large Reduced consequences of a large break LOCA. N/A - Enhancement due to procedure revisions are not break LOCA. applicable to the design certification stage of plant development.

149 Install computer aided instrumentation Improved prevention of core melt sequences by N/A - Enhancements to improve procedural compliance are system to assist the operator in assessing making operator actions more reliable. not applicable to the design certification stage of plant post-accident plant status. development.

150 Improve maintenance procedures. Improved prevention of core melt sequences by N/A - Enhancement due to procedure revisions are not increasing reliability of important equipment. applicable to the design certification stage of plant development.

T-33 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 5 (19 of 19)

SAMA ID Potential Enhancement Result of Potential Enhancement Qualitative Screening (NEI-05-01) (SAMA Title) 151 Increase training and operating Improved likelihood of success of operator actions N/A - Enhancement due to training is not applicable to the experience feedback to improve operator taken in response to abnormal conditions. design certification stage of plant development SAMDA.

response. (Combined into the specific operator action SAMDAs) 152 Develop procedures for transportation and Reduced consequences of transportation and nearby N/A - Enhancement due to procedure revisions are not nearby facility accidents. facility accidents. applicable to the design certification stage of plant development.

153 Install secondary side guard pipes up to Prevents secondary side depressurization should a Secondary line breaks are a negligible contribution to plant the main steam isolation valves. steam line break occur upstream of the main steam risk. Therefore, any design change related to instrument air isolation valves. Also guards against or prevents would provide a negligible benefit.

consequential multiple steam generator tube ruptures following a main steam line break event.

T-34 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (1 of 11)

List of Basic Events from APR1400 PRA CDF Importance Analysis (At-Power Internal Events)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 1 RCOPH-S-SDSE-FW 1.41E-02 28.76% Operator Fails to Open POSRVs in Early Procedural changes are not in the scope of this SAMDA analysis Phase for F&B Operation 2 PFLOOP-SI 2.00E-02 19.93% CONDITIONAL LOOP AFTER Conditional LOOP event - no impact on SAMDA analysis INITIATORS WHICH INITIATE AN SI SIGNAL 3 %LOOP-GR 1.16E-02 13.38% GRID-RELATED LOOP Initiating event - no impact on SAMDA analysis 4 FWOPH-S-ERY 2.11E-02 11.97% Operate Fails to Align Startup Feedwater Procedural changes are not in the scope of this SAMDA analysis pump PP07 (Early Phase) 5 %MLOCA 4.85E-04 11.61% MEDIUM LOSS OF COOLANT ACCIDENT Initiating event - no impact on SAMDA analysis 6 %GTRN 6.56E-01 11.35% GENERAL TRANSIENT Initiating event - no impact on SAMDA analysis 7 %LOOP-SW 9.88E-03 10.73% SWITCHYARD-CENTERED LOOP Initiating event - no impact on SAMDA analysis 8 AFTPR1A-TDP01A 3.52E-02 10.22% AFW TDP PP01A FAILS TO RUN FOR > The component associated with this basic event is evaluated in 1HR Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

9 %LOOP-WE 3.71E-03 9.89% WEATHER-RELATED LOOP Initiating event - no impact on SAMDA analysis 10 AFPVKQ4-TP01A/B/MP02A/B 1.11E-05 9.72% 4/4 CCF OF AFW TDP01A/B/MDP02A/B The components associated with this basic event are evaluated in FAIL TO RUN Sections 7.3.3 through 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

11 AFTPR1B-TDP01B 3.52E-02 8.64% AFW TDP PP01B FAILS TO RUN FOR > The component associated with this basic event is evaluated in 1HR Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

12 COMBINATION_130 3.60E+01 8.41% HEP dependency factor for FWOPH-S-ERY, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 13 %LSSB-D 7.32E-03 7.59% LARGE SECONDARY SIDE BREAK (MSIV Initiating event - no impact on SAMDA analysis DOWNDSTREAM) 14 DGDGM-A-DGA 1.44E-02 7.27% DG 01A UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

15 DGDGM-B-DGB 1.44E-02 6.87% DG 01B UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-35 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (2 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 16 %SGTR 1.31E-03 6.81% STEAM GENERATOR TUBE RUPTURE Initiating event - no impact on SAMDA analysis 17 DCBTM-B-BT01B 2.72E-03 5.97% CLASS 1E 125V DC BATTERY BT01B The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

18 RAC-16H-WE 1.59E-01 5.89% NON-RECOVERY PROBABILITY OF This event represents characteristics of the site at which the plant OFFSITE POWER WITHIN 16HR will be located and the probability is based on generic industry (WEATHER RELATED) data. Design changes to affect the risk from site characteristics are not applicable to the SAMDA analysis and this event is not considered further.

19 %SLOCA 2.40E-03 5.83% SMALL LOSS OF COOLANT ACCIDENT Initiating event - no impact on SAMDA analysis 20 DATGR-S-AACTG 1.57E-01 5.83% FAILS TO RUN AAC GAS TURBINE The component associated with this basic event is evaluated in GENERATOR Section 7.2.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

21 DCBTM-A-BT01A 2.72E-03 5.43% CLASS 1E 125V DC BATTERY BT01A The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

22 AFMVC1B-046 5.78E-02 5.32% AFW ISOL. MOV V046 FAILS TO CLOSE The component associated with this basic event is evaluated in Section 7.3.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

23 AFMVO1B-046 5.78E-02 5.32% AFW ISOL. MOV V046 FAILS TO OPEN The component associated with this basic event is evaluated in Section 7.3.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

24 AFMVC1A-045 5.78E-02 5.14% AFW ISOL. MOV V045 FAILS TO CLOSE The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

25 AFMVO1A-045 5.78E-02 5.14% AFW ISOL. MOV V045 FAILS TO OPEN The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

26 %FWLB 1.74E-03 4.80% FEEDWATER LINE BREAK Initiating event - no impact on SAMDA analysis 27 PI-SGTR 2.70E-02 4.40% PRESSURE INDUECD SGTR This event would affect a portion of offsite consequences only.

PROBABILITY UNDER LSSB, ATWS, The benefit of eliminating this failure mode would be negligible.

FWLB T-36 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (3 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 28 WOCHM2A-CH02A 4.00E-02 4.16% ECW CHILLER 02A TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.15.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

29 WOCHM2B-CH02B 4.00E-02 3.90% ECW CHILLER 02B TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

30 DGDGR-A-DGA 2.50E-02 3.83% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

31 DGDGR-C-DGC 2.50E-02 3.76% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01C Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

32 DGDGR-D-DGD 2.50E-02 3.49% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01D Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

33 IPINM-B-IN01B 2.00E-03 3.48% CLASS 1E 120V AC INVERTER IN01B The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

34 SISPP-S-IRWST 1.22E-05 3.36% CCF OF IRWST SUMPS DUE TO The component associated with this basic event is evaluated in PLUGGING Section 7.16.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

35 DGDGR-B-DGB 2.50E-02 3.12% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

36 IPINM-A-IN01A 2.00E-03 3.08% CLASS 1E 120V AC INVERTER IN01A The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

37 DGDGM-C-DGC 1.44E-02 2.97% DG 01C UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-37 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (4 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 38 %TLOCCW 2.34E-04 2.95% TOTAL LOSS OF COMPONANT COOLING Initiating event - no impact on SAMDA analysis WATER 39 %TLOESW 2.34E-04 2.95% TOTAL LOSS OF ESSENTIAL SERVICE Initiating event - no impact on SAMDA analysis WATER 40 PFHBO1A-SW01A-H2 6.66E-03 2.94% PCB SW01A-H2 4.16KV SWGR SW01A The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 41 PPSO-AP-LC 1.20E-05 2.92% CCF OF PPS LC APPLICATION The component associated with this basic event is evaluated in SOFTWARE Section 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

42 PFHBO1B-SW01B-H2 6.66E-03 2.91% PCB SW01B-H2 4.16KV SWGR SW01B The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

43 DGDGM-D-DGD 1.44E-02 2.81% DG 01D UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

44 %RVR 3.06E-08 2.79% REACTOR VESSEL RUPTURE Initiating event - no impact on SAMDA analysis 45 PFLOOP-NO-SI 2.00E-03 2.62% CONDITIONAL LOOP AFTER Conditional LOOP event - no impact on SAMDA analysis INITIATORS WHICH DO NOT INITIATE AN SI SIGNAL 46 WOCHS1A-CH01A 1.30E-02 2.61% FAILS TO START ECW CHILLER CH01A The component associated with this basic event is evaluated in Section 7.15.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

47 WOCHS1B-CH01B 1.30E-02 2.38% FAILS TO START ECW CHILLER CH01B The component associated with this basic event is evaluated in Section 7.15.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

48 SXFLP-S-FT0123AB 5.57E-05 2.35% CCF OF ALL ESW DERIS FILTERS DUE The component associated with this basic event is evaluated in TO PLUGGING Section 7.17.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

49 SXMPM2A-PP02A 2.64E-02 2.18% ESW PUMP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.17.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-38 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (5 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 50 I-ATWS-RPMCF 2.98E-07 2.17% CCF TO SCRAM DUE TO MECHANICAL The component associated with this basic event is evaluated in FAILURES (1HR MT) Section 7.20. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

51 MSOPV-S-MSIS 1.00E-01 2.13% OPERATOR FAILS TO RECOVERY FOR Procedural changes are not in the scope of this SAMDA analysis MSIS 52 %LOCV 5.57E-02 2.08% LOSS OF CONDENCER VACCUM Initiating event - no impact on SAMDA analysis 53 SXMPM2B-PP02B 2.64E-02 2.05% ESW PUMP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.17.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

54 %LOFW 6.55E-02 2.00% LOSS OF MAIN FEEDWATER Initiating event - no impact on SAMDA analysis 55 AFTPKD2-TDP01A/B 6.89E-04 1.95% 2/2 CCF OF AFW TDP PP01/A/B FAILS TO The components associated with this basic event are evaluated in RUN > 1 HR Sections 7.3.3 and 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

56 DGDGKQ4-DG01ABCD 5.95E-05 1.90% 4/4 CCF OF EDG 01A/01B/01C/01D FAIL The components associated with this basic event are evaluated in TO RUN Sections 7.1.1 through 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

57 AFMPM2A-MDP02A 3.98E-03 1.72% AFW MDP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.3.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

58 AFTPS1A-TDP01A 6.49E-03 1.70% AFW TDP PP01A FAILS TO START The component associated with this basic event is evaluated in Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

59 DATGM-S-AACTG 5.00E-02 1.70% AAC DG UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.2.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

60 WOCHWQ4-CH01A/2A/1B/2B 3.86E-05 1.63% 4/4 CCF OF ECW CHILLERS 1A/2A/1B/2B The components associated with this basic event are evaluated in FAIL TO START Sections 7.15.3 through 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

61 DGDGL-A-DGA 3.78E-03 1.61% DG A FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-39 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (6 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 62 DGDGL-B-DGB 3.78E-03 1.51% DG B FAILS TO LOAD AND RUN DURING The component associated with this basic event is evaluated in 1ST 1HR OF OPERATION Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

63 %LOOP-PL 1.83E-03 1.49% PLANT-CENTERED LOOP Initiating event - no impact on SAMDA analysis 64 MSOPH-S-SGADV-HW 7.45E-02 1.47% OPERATOR FAILS TO OPEN ADVS Procedural changes are not in the scope of this SAMDA analysis USING HAND WHEEL 65 CSMPM2B-PP01B 7.12E-03 1.42% CS PUMP PP01B UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.6.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

66 AFTPS1B-TDP01B 6.49E-03 1.41% AFW TDP PP01B FAILS TO START The component associated with this basic event is evaluated in Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

67 AFTPM1A-TDP01A 5.39E-03 1.40% AFW TDP PP01A UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T/M Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

68 DGSQA-A-LOADSQ 3.33E-03 1.39% LOAD SEQUNCER A FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

69 RAC-16H-GR 1.01E-02 1.37% NON-RECOVERY PROBABILITY OF This event represents characteristics of the site at which the plant OFFSITE POWER WITHIN 16HR (GRID will be located and the probability is based on generic industry RELATED) data. Design changes to affect the risk from site characteristics are not applicable to the SAMDA analysis and this event is not considered further.

70 WOMPM2A-PP02A 1.42E-02 1.36% ECW PP02A TRAIN UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.18.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

71 CSMPM2A-PP01A 7.12E-03 1.33% CS PUMP 1 PP01A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.6.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

72 DGSQA-B-LOADSQ 3.33E-03 1.29% LOAD SEQUNCER A FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-40 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (7 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 73 FWMPM-S-PP07 7.12E-03 1.26% START-UP FW PUMP PP07 The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.3.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

74 DCBTM-C-BT01C 2.72E-03 1.24% CLASS 1E 125V DC BATTERY BT01C The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

75 DCBTM-D-BT01D 2.72E-03 1.24% CLASS 1E 125V DC BATTERY BT01D The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

76 WOMPM2B-PP02B 1.42E-02 1.23% ECW PP02B TRAIN UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.18.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

77 PFHBO2A-SW01C-C2 6.66E-03 1.23% PCB SW01C-C2 4.16KV SWGR SW01C The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

78 PFHBO2B-SW01D-G2 6.66E-03 1.21% PCB SW01D-G2 4.16KV SWGR SW01D The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

79 WOCHS2A-CH02A 1.30E-02 1.19% FAILS TO START ECW CHILLER CH02A The component associated with this basic event is evaluated in Section 7.15.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

80 DGDGS-A-DGA 2.89E-03 1.17% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

81 AFTPM1B-TDP01B 5.39E-03 1.15% AFW TDP PP01B UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T/M Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

82 CSHEM2B-HE01B 2.50E-03 1.13% CS HX HE01B FAILS DUE TO The component associated with this basic event evaluated in TEST/MAINTENANCE Section 7.6.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-41 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (8 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 83 AFTPL1A-TDP01A 4.42E-03 1.13% AFW TDP PP01A FAILS TO RUN FOR < The component associated with this basic event is evaluated in 1HR Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

84 CSHEM2A-HE01A 2.50E-03 1.12% CS HX HE01A FAILS DUE TO T&M The component associated with this basic event evaluated in Section 7.6.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

85 WOCHS2B-CH02B 1.30E-02 1.11% FAILS TO START ECW CHILLER CH02B The component associated with this basic event is evaluated in Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

86 DGDGS-B-DGB 2.89E-03 1.09% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

87 COMBINATION_2038 7.10E+01 1.08% HEP dependency factor for MSOPV-S-MSIS, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 88 %LSSB-U 3.49E-04 1.05% LARGE SECONDARY SIDE BREAK (MSIV Initiating event - no impact on SAMDA analysis UPSTREAM) 89 VOHVM2A-HV33A 2.50E-03 1.05% CUBICLE COOLER HV33A UAVAILABLE The component associated with this basic event is evaluated in DUE TO T&M Section 7.15.21. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

90 AFOPH-S-ALT-LT 7.10E-04 0.96% Operator Fails to Transfer AFW Source From Procedural changes are not in the scope of this SAMDA analysis AFWST to RWT/CST 91 RCOPH-S-SDSL 8.10E-03 0.95% OPERATOR FAILS TO OPEN 1 OF 4 SDS Procedural changes are not in the scope of this SAMDA analysis VALVE LATE PHASE 92 PPSO-AP-GC 1.20E-05 0.93% CCF OF PPS GC APPLICATION The component associated with this basic event is evaluated in SOFTWARE Section 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

93 AFTPL1B-TDP01B 4.42E-03 0.93% AFW TDP PP01B FAILS TO RUN FOR < The component associated with this basic event is evaluated in 1HR Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

94 COMBINATION_7 7.12E+00 0.81% HEP dependency factor for AFOPH-S-ALT- Procedural changes are not in the scope of this SAMDA analysis LT, RCOPH-S-SDSL 95 SIMPM2A-PP02C 3.88E-03 0.81% SI PUMP PP02C UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.16.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-42 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (9 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 96 WOCHKQ4-CH01A/1B/2A/2B 4.86E-06 0.80% 4/4 CCF OF ECW CHILLERS 1A/2A/1B/2B The components associated with this basic event are evaluated in FAIL TO RUN Section 7.15.3 through 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

97 CCMVWD2-097/8 1.70E-05 0.76% 2/2 CCF OF CCW MOV V097/098 FAIL TO The components associated with this basic event are evaluated in OPEN Sections 7.5.3 and 7.5.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

98 IPINM-C-IN01C 2.00E-03 0.75% CLASS 1E 120V AC INVERTER IN01C The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

99 AFMPM2B-MDP02B 3.98E-03 0.75% AFW MDP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

100 %LLOCA-HL2 5.05E-07 0.73% LARGE LOCA IN HOT LEG 2 (SDC Initiating event - no impact on SAMDA analysis LOOP2) 101 IPINM-D-IN01D 2.00E-03 0.72% CLASS 1E 120V AC INVERTER IN01D The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

102 CCMPM2A-PP02A 9.58E-03 0.70% CCW PUMP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.5.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

103 PFHBWQ4-SW2OUAT 2.73E-05 0.70% 4/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1B/1C/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 104 MTC-UET-TTS-0PF 2.70E-02 0.70% ADVERSE MTC UET PERCENTAGE Quantification factor - no impact on SAMDA analysis GIVEN TURBINE TRIP WHEN NO POSRVS FAIL 105 DGDGL-C-DGC 3.78E-03 0.69% DG 01C FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

106 SIMPM2B-PP02D 3.88E-03 0.68% SI PUMP 4 (PP02D) UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.16.8. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-43 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (10 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 107 %PLOCCW 2.10E-03 0.67% PARTIAL LOSS OF COMPONANT Initiating event - no impact on SAMDA analysis COOLING WATER 108 RAC-12H-WE 1.97E-01 0.66% NON-RECOVERY PROBABILITY OF This event represents characteristics of the site at which the plant OFFSITE POWER WITHIN 9.5HR will be located and the probability is based on generic industry (WEATHER RELATED) data. Design changes to affect the risk from site characteristics are not applicable to the SAMDA analysis and this event is not considered further.

109 CCMPM2B-PP02B 9.58E-03 0.65% CCW PUMP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.6.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

110 DGDGL-D-DGD 3.78E-03 0.65% DG D FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

111 CSMVWD2-003/004 1.43E-05 0.64% 2/2 CCF OF ISOL. MOV 003/004 IN CS TRS The components associated with this basic event are evaluated in HX DISCH. PATH FAIL TO OPEN Sections 7.6.3 and 7.6.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

112 MSEVXQ2-011/13 2.25E-05 0.63% 2/2 CCF OF 2/4 MSIV 011/013 FAIL TO CLOSE 113 MSEVXQ2-011/14 2.25E-05 0.63% 2/2 CCF OF 2/4 MSIV 011/014 FAIL TO CLOSE 114 MSEVXQ2-012/13 2.25E-05 0.63% 2/2 CCF OF 2/4 MSIV 012/013 FAIL TO CLOSE 115 MSEVXQ2-012/14 2.25E-05 0.63% 2/2 CCF OF 2/4 MSIV 012/014 FAIL TO CLOSE 116 DGSQA-C-LOADSQ 3.33E-03 0.60% LOAD SEQUNCER C FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

117 VKOPH-S-ECCS 1.00E-01 0.60% OPERATOR FAILS TO ACTUATE ECCS Procedural changes are not in the scope of this SAMDA analysis EXHAUST FAN AH01A/B 118 VDHVL-A-HV12A 2.28E-03 0.56% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV12A FOR 1HR Section 7.15.11. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

119 VDHVL-A-HV13A 2.28E-03 0.56% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV13A FOR 1HR Section 7.15.16. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-44 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6a (11 of 11)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 120 DGSQA-D-LOADSQ 3.33E-03 0.56% LOAD SEQUNCER D FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

121 SIMPR2A-PP02C 2.83E-03 0.56% FAILS TO RUN SI PUMP PP02C The component associated with this basic event is evaluated in Section 7.16.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

122 VDHVL-B-HV12B 2.28E-03 0.52% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV12B FOR 1HR Section 7.15.11. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

123 VDHVL-B-HV13B 2.28E-03 0.52% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV13B FOR 1HR Section 7.15.16. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

124 DGDGS-C-DGC 2.89E-03 0.51% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01C Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

125 WOOPH-A-CROSSTIE 5.00E-01 0.50% OPERATOR FAILS TO OPEN 1025A AND Procedural changes are not in the scope of this SAMDA analysis ALIGN FLOW PATH 126 %PLOESW 1.63E-03 0.50% PARTIAL LOSS OF ESSENTIAL SERVICE Initiating event - no impact on SAMDA analysis WATER T-45 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (1 of 9)

List of Basic Events from APR1400 PRA CDF Importance Analysis (At-Power Internal Flooding Events)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 1 RCOPH-S-SDSE-FW 1.41E-02 22.82% Operator Fails to Open POSRVs in Early Procedural changes are not in the scope of this SAMDA analysis Phase for F&B Operation 2 PFHBO1A-SW01A-H2 6.66E-03 19.73% PCB SW01A-H2 4.16KV SWGR SW01A The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 3 %IE-078-19B-FP-X 3.32E-04 18.52% MAJ BRK OF FP PIPING IN RM 078-A19B, Initiating event - no impact on SAMDA analysis 078-A20B, 100-A10B OR 120-A11B 4 %IE-100-20A-FP-X 3.18E-04 17.88% MAJ BRK OF FP PIPING IN A QUAD 100 Initiating event - no impact on SAMDA analysis FT EL RM 100-A20A AND OTHERS 5 PFHBO1B-SW01B-H2 6.66E-03 17.25% PCB SW01B-H2 4.16KV SWGR SW01B The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

6 %IE-078-19A-FP-X 2.83E-04 16.03% MAJ BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A19A AND OTHER A QUAD RMS 7 %IE-078-44B-FP-X 2.07E-04 12.03% MAJ BRK IN FP PIPING IN B QUAD 78 FT Initiating event - no impact on SAMDA analysis EL RM 078-A44B AND OTHER B QUAD RMS 8 PFHBWQ4-SW2OUAT 2.73E-05 11.68% 4/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1B/1C/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 9 AFMVC1A-045 5.78E-02 9.62% AFW ISOL. MOV V045 FAILS TO CLOSE The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

10 AFMVO1A-045 5.78E-02 9.62% AFW ISOL. MOV V045 FAILS TO OPEN The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

11 FPOPH-1-ISO-FL 9.48E-03 8.83% Operator fails to isolate FP break with less Procedural changes are not in the scope of this SAMDA analysis than 20 minutes available 12 AFMVC1B-046 5.78E-02 8.62% AFW ISOL. MOV V046 FAILS TO CLOSE The component associated with this basic event is evaluated in Section 7.3.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-46 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (2 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 13 AFMVO1B-046 5.78E-02 8.62% AFW ISOL. MOV V046 FAILS TO OPEN The component associated with this basic event is evaluated in Section 7.3.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

14 FPOPH-2-ISO-FL 8.00E-03 7.71% Operator fails to isolate FP break with between Procedural changes are not in the scope of this SAMDA analysis 20 and 40 minutes available 15 COMBINATION_60 7.10E+01 7.24% HEP dependency factor for FPOPH-1-ISO-FL, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 16 WOCHM2A-CH02A 4.00E-02 6.93% ECW CHILLER 02A TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.15.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

17 WOCHM2B-CH02B 4.00E-02 6.62% ECW CHILLER 02B TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

18 AFTPR1A-TDP01A 3.52E-02 6.18% AFW TDP PP01A FAILS TO RUN FOR > The component associated with this basic event is evaluated in 1HR Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

19 %IE-078-19B-FP-M 1.27E-04 5.88% MOD BRK OF FP PIPING IN RM 078-A19B, Initiating event - no impact on SAMDA analysis 078-A20B, 100-A10B OR 120-A11B 20 AFTPR1B-TDP01B 3.52E-02 5.60% AFW TDP PP01B FAILS TO RUN FOR > The component associated with this basic event is evaluated in 1HR Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

21 PPSO-AP-LC 1.20E-05 5.26% CCF OF PPS LC APPLICATION The component associated with this basic event is evaluated in SOFTWARE Section 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

22 %IE-078-01D-FP-X 1.62E-04 5.18% MAJ BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A01D AND OTHER B QUAD RMS 23 PFHBO2A-SW01C-C2 6.66E-03 5.02% PCB SW01C-C2 4.16KV SWGR SW01C The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.8. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

24 AFOPH-1-ISO-FL 1.00E+00 4.70% Operator fails to isolate major break of AF Procedural changes are not in the scope of this SAMDA analysis piping in TDAFP room.

25 %IE-078-15D-AF-X 1.88E-05 4.60% MAJ BRK (>3200 GPM) IN AF PIPING IN D Initiating event - no impact on SAMDA analysis QUAD 78 FT EL RM 078-A15D 26 %IE-078-10C-FP-X 3.33E-04 4.42% MAJ BRK (>3700 GPM) IN FP PIPING IN C Initiating event - no impact on SAMDA analysis QUAD 78 FT EL RM 078-A10C T-47 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (3 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 27 COMBINATION_62 7.10E+01 4.33% HEP dependency factor for FPOPH-2-ISO-FL, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 28 SXMPM2A-PP02A 2.64E-02 4.28% ESW PUMP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.17.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

29 SXMPM2B-PP02B 2.64E-02 4.15% ESW PUMP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.17.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

30 AFMPM2A-MDP02A 3.98E-03 3.78% AFW MDP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.3.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

31 PFHBO2B-SW01D-G2 6.66E-03 3.62% PCB SW01D-G2 4.16KV SWGR SW01D The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

32 %IE-078-19A-FP-M 7.89E-05 3.62% MOD BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A19A AND OTHER A QUAD RMS 33 WOOPH-B-1/2B 2.06E-02 3.42% OPERATOR FAILS TO OPERATE ECW Procedural changes are not in the scope of this SAMDA analysis PUMPS PP01/2B 34 PFHBWQ2-SW2OUATAC 6.03E-05 3.38% 2/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1C FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 35 PFHBWQ3-SW2OUATACD 1.65E-05 3.26% 3/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1C/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 36 AFOPH-S-ALT-LT 7.10E-04 3.24% Operator Fails to Transfer AFW Source From Procedural changes are not in the scope of this SAMDA analysis AFWST to RWT/CST 37 AFMPM2B-MDP02B 3.98E-03 3.22% AFW MDP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

38 PFHBWQ3-SW2OUATBCD 1.65E-05 2.91% 3/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01B/1C/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 39 WOOPH-A-1/2A 2.06E-02 2.76% OPERATOR FAILS TO OPERATE ECW Procedural changes are not in the scope of this SAMDA analysis PUMPS PP01/2A T-48 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (4 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 40 %IE-100-10B-FP-X 5.42E-05 2.74% MAJ BRK (>1445 GPM) IN FP PIPING IN B Initiating event - no impact on SAMDA analysis QUAD 100 FT EL RM 100-A10B 41 PFHBWQ2-SW2OUATBD 6.03E-05 2.74% 2/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01B/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 42 RCOPH-S-SDSL 8.10E-03 2.73% OPERATOR FAILS TO OPEN 1 OF 4 SDS Procedural changes are not in the scope of this SAMDA analysis VALVE LATE PHASE 43 DGDGR-D-DGD 2.50E-02 2.58% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01D Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

44 WOMPM2A-PP02A 1.42E-02 2.50% ECW PP02A TRAIN UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.18.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

45 DGDGR-C-DGC 2.50E-02 2.40% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01C Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

46 VOHVM2A-HV33A 2.50E-03 2.34% CUBICLE COOLER HV33A UAVAILABLE The component associated with this basic event is evaluated in DUE TO T&M Section 7.15.21. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

47 WOMPM2B-PP02B 1.42E-02 2.22% ECW PP02B TRAIN UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.18.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

48 WOCHS2A-CH02A 1.30E-02 2.15% FAILS TO START ECW CHILLER CH02A The component associated with this basic event is evaluated in Section 7.15.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

49 COMBINATION_110 1.10E+01 2.10% HEP dependency factor for AFOPH-1-ISO- Procedural changes are not in the scope of this SAMDA analysis FL, RCOPH-S-SDSE-FW 50 WOCHS2B-CH02B 1.30E-02 2.05% FAILS TO START ECW CHILLER CH02B The component associated with this basic event is evaluated in Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

51 VOHVM1B-HV33B 2.50E-03 2.00% CUBICLE COOLER HV33B UAVAILABLE The component associated with this basic event is evaluated in DUE TO T&M Section 7.15.22. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-49 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (5 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 52 %IE-078-31A-FP-X 2.37E-04 1.97% MAJ BRK (> 3900 GPM) IN FP PIPING IN A Initiating event - no impact on SAMDA analysis QUAD 78 FT EL RM 078-A31A 53 FPOPH-3DEP-ISO-FL 2.93E-03 1.97% Operator fails to isolate major break of FP Procedural changes are not in the scope of this SAMDA analysis piping in 078-A31A before 18-inches of accumulation.

54 PFHBWQ3-SW2OUATABC 1.65E-05 1.86% 3/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1B/1C FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 55 DCBTM-A-BT01A 2.72E-03 1.71% CLASS 1E 125V DC BATTERY BT01A The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

56 DCBTM-B-BT01B 2.72E-03 1.56% CLASS 1E 125V DC BATTERY BT01B The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

57 PFHBC1A-SW01A-A2 6.66E-03 1.50% PCB SW01A-A2 OF 4.16KV SWGR SW01A The component associated with this basic event is evaluated in FAILS TO CLOSE Section 7.11.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

58 CCMPM2A-PP02A 9.58E-03 1.49% CCW PUMP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.5.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

59 DGDGM-D-DGD 1.44E-02 1.45% DG 01D UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

60 COMBINATION_64 2.42E+04 1.45% HEP dependency factor for FPOPH-2-ISO-FL, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW, FPOPH-3DEP-ISO-FL 61 NPXHM-M-SAT02M 1.75E-03 1.45% SAT TR02M UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.11.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

62 CCMPM2B-PP02B 9.58E-03 1.44% CCW PUMP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.5.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-50 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (6 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 63 DGDGR-B-DGB 2.50E-02 1.38% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

64 NPXHM-N-SAT02N 1.75E-03 1.37% SAT TR02N UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.11.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

65 PFHBC1B-SW01B-A2 6.66E-03 1.37% PCB SW01B-A2 OF 4.16KV SWGR SW01B The component associated with this basic event is evaluated in FAILS TO CLOSE Section 7.11.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

66 DGDGM-C-DGC 1.44E-02 1.35% DG 01C UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

67 CDOPH-S-ALIGN 8.60E-04 1.27% Operator Fails to Align the Manual Valves and Procedural changes are not in the scope of this SAMDA analysis start CD pumps for Hotwell Makeup 68 %IE-078-01D-FP-M 5.24E-05 1.22% MOD BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A01D AND OTHER B QUAD RMS 69 %IE-TB-MISC 1.17E-02 1.17% ANY TB FLOOD <400,000 GPM Initiating event - no impact on SAMDA analysis 70 DGDGR-A-DGA 2.50E-02 1.07% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

71 PFHBWQ3-SW2OUATABD 1.65E-05 1.05% 3/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1B/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 72 AFTPS1A-TDP01A 6.49E-03 1.01% AFW TDP PP01A FAILS TO START The component associated with this basic event is evaluated in Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

73 AFTPS1B-TDP01B 6.49E-03 0.93% AFW TDP PP01B FAILS TO START The component associated with this basic event is evaluated in Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

74 WOCHR1A-CH01A 7.32E-04 0.90% FAILS TO RUN ECW CHILLER CH01A The component associated with this basic event is evaluated in FOR 24 HOURS Section 7.15.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-51 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (7 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 75 AFTPM1A-TDP01A 5.39E-03 0.83% AFW TDP PP01A UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T/M Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

76 IPINM-A-IN01A 2.00E-03 0.81% CLASS 1E 120V AC INVERTER IN01A The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

77 %IE-120-11B-FP-X 1.70E-05 0.81% MAJ BRK (>1180 GPM) OF FP PIPING IN B Initiating event - no impact on SAMDA analysis QUAD 120 FT EL RM 120-A11B OR 120-A13B 78 DGDGM-B-DGB 1.44E-02 0.79% DG 01B UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

79 AFTPM1B-TDP01B 5.39E-03 0.76% AFW TDP PP01B UNAVAILABLE DUE TO The component associated with this basic event is T/M evaluated in Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

80 %IE-100-37B-FP-X 9.44E-05 0.74% MOD BRK OF FP PIPING IN B QUAD 100 Initiating event - no impact on SAMDA analysis FT EL RM 100-A37B AND OTHERS 81 IPINM-B-IN01B 2.00E-03 0.74% CLASS 1E 120V AC INVERTER IN01B The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

82 VOHVS2A-HV33A 8.29E-04 0.74% FAILS TO START OF MAFP ROOM A The component associated with this basic event is evaluated in CUBICLE COOLER HV33A Section 7.15.21. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

83 AFPVKQ4-TP01A/B/MP02A/B 1.11E-05 0.70% 4/4 CCF OF AFW TDP01A/B/MDP02A/B The components associated with this basic event are evaluated in FAIL TO RUN Sections 7.3.3 through 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

84 RCPVO-A-200 3.54E-03 0.68% POSRV V200 FAILS TO OPEN The component associated with this basic event is evaluated in (HARDWARE FAIL) Section 7.12.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

85 RCPVO-C-201 3.54E-03 0.68% POSRV V201 FAILS TO OPEN The component associated with this basic event is evaluated in (HARDWARE FAIL) Section 7.12.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-52 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (8 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 86 AFTPL1A-TDP01A 4.42E-03 0.66% AFW TDP PP01A FAILS TO RUN FOR < The component associated with this basic event is evaluated in 1HR Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

87 FWOPH-S-LNG 3.00E-03 0.66% OPERATOR FAILS TO ALINE STARTUP Procedural changes are not in the scope of this SAMDA analysis FEEDWATER PUMP PP07 (LATE PHASE) 88 RCPVO-B-202 3.54E-03 0.66% POSRV V202 FAILS TO OPEN The component associated with this basic event is evaluated in (HARDWARE FAIL) Section 7.12.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

89 RCPVO-D-203 3.54E-03 0.66% POSRV V203 FAILS TO OPEN The component associated with this basic event is evaluated in (HARDWARE FAIL) Section 7.12.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

90 COMBINATION_61 4.50E+00 0.65% HEP dependency factor for WOOPH-B-1/2B, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 91 COMBINATION_7 7.12E+00 0.65% HEP dependency factor for AFOPH-S-ALT- Procedural changes are not in the scope of this SAMDA analysis LT, RCOPH-S-SDSL 92 CSMPM2A-PP01A 7.12E-03 0.64% CS PUMP 1 PP01A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.6.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

93 FWOPH-S-ERY 2.11E-02 0.64% Operator Fails to Align Startup Feedwater Procedural changes are not in the scope of this SAMDA analysis pump PP07 (Early Phase) 94 VOHVS2B-HV33B 8.29E-04 0.63% FAILS TO START OF MAFP ROOM B The component associated with this basic event is evaluated in CUBICLE COOLER HV33B Section 7.15.22. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

95 COMBINATION_1 4.21E+02 0.61% HEP dependency factor for AFOPH-S-ALT- Procedural changes are not in the scope of this SAMDA analysis LT, CDOPH-S-ALIGN,RCOPH-S-SDSL 96 DGDGM-A-DGA 1.44E-02 0.61% DG 01A UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

97 AFTPL1B-TDP01B 4.42E-03 0.61% AFW TDP PP01B FAILS TO RUN FOR < The component associated with this basic event is evaluated in 1HR Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

98 COMBINATION_63 4.50E+00 0.61% HEP dependency factor for WOOPH-A-1/2A, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW T-53 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6b (9 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 99 PFHBC2A-SW01C-A2 6.66E-03 0.59% PCB SW01C-A2 OF 4.16KV SWGR SW01C The component associated with this basic event is evaluated in FAILS TO CLOSE Section 7.11.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

100 SXCTM-2A-CT02A 4.00E-03 0.59% SXCT CT02A UNAVAILABLE DUE TO T&M 101 WOCHR1B-CH01B 7.32E-04 0.59% FAILS TO RUN ECW CHILLER 01B FOR 24 HOURS 102 VGAHM2A-AH02A 4.00E-03 0.59% ESW PUMP A FAN 605-VG-AH02A UNAVAILABLE DUE TO T&M 103 SXCTM-2B-CT02B 4.00E-03 0.57% SXCT CT02B UNAVAILABLE DUE TO T&M 104 VGAHM2B-AH02B 4.00E-03 0.57% ESW PUMP B FAN 605-VG-AH02B UNAVAILABLE DUE TO T&M 105 VGAHS2A-AH02A 3.86E-03 0.56% FAILS TO START OF EWS PUMP ROOM I.

SUPPLY FAN AH02A 106 VGAHS2B-AH02B 3.86E-03 0.54% FAILS TO START EWS PUMP ROOM II.

SUPPLY FAN AH02B 107 PFLOOP-NO-SI 2.00E-03 0.54% CONDITIONAL LOOP AFTER Conditional LOOP event - no impact on SAMDA analysis INITIATORS WHICH DO NOT INITIATE AN SI SIGNAL 108 PPSO-OS-PPS 1.20E-06 0.53% CCF OF PPS OPERATING SYSTEM The component associated with this basic event is evaluated in SOFTWARE Section 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

109 PFHBWQ2-SW2OUATAD 6.03E-05 0.51% 2/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 110 PFHBWQ2-SW2OUATBC 6.03E-05 0.50% 2/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01B/1C FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit T-54 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (1 of 9)

List of Basic Events from APR1400 PRA CDF Importance Analysis (At-Power Internal Fire Events)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 1 ASD-CDF 1.00E-01 27.66% FAILURE OF ALTERNATE SHUTDOWN This event represents operator actions and procedural changes are AFTER MCR EVACUATION (CORE not in the scope of this SAMDA analysis DAMAGE) 2 RCOPH-S-SDSE-FW 2.59E-02 13.92% Operator Fails to Open POSRVs in Early Procedural changes are not in the scope of this SAMDA analysis Phase for F&B Operation 3 %F157-AMCR-4-4 2.36E-06 10.63% FIRE IN F157-AMCR - TRANSIENT FIRE - Initiating event - no impact on SAMDA analysis UNSUPPRESSED - ASD 4 %F000-TB-LOOP2 3.52E-04 8.13% FIRE IN F000-TB-LOOP2 - TB FIRES Initiating event - no impact on SAMDA analysis LEADING TO LOOP (SEVERE) 5 AFOPH-S-ALT-LT 3.86E-03 7.54% Operator Fails to Transfer AFW Source From Procedural changes are not in the scope of this SAMDA analysis AFWST to RWT/CST 6 %F157-AMCR-3-4 1.51E-06 6.83% FIRE IN F157-AMCR - SAFETY CONSOLE Initiating event - no impact on SAMDA analysis FIRE - UNSUPPRESSED - ASD 7 RCOPH-S-SDSL 8.99E-03 5.53% OPERATOR FAILS TO OPEN 1 OF 4 SDS Procedural changes are not in the scope of this SAMDA analysis VALVE LATE PHASE 8 RCOPH-S-RCPTRIP 5.63E-02 5.52% Operator Fails to Trip RCPs Following Loss of Procedural changes are not in the scope of this SAMDA analysis Seal Cooling 9 %F078-A19B-U 7.27E-04 5.23% FIRE IN F078-A19B - CORRIDOR - Initiating event - no impact on SAMDA analysis UNSUPPRESSED 10 AFMVC1A-045 5.78E-02 5.12% AFW ISOL. MOV V045 FAILS TO CLOSE The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

11 AFMVO1A-045 5.78E-02 5.12% AFW ISOL. MOV V045 FAILS TO OPEN The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

12 PPSO-AP-LC 1.20E-05 5.03% CCF OF PPS LC APPLICATION The component associated with this basic event is evaluated in SOFTWARE Section 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

13 DATGR-S-AACTG 1.57E-01 4.96% FAILS TO RUN AAC GAS TURBINE The component associated with this basic event is evaluated in GENERATOR Section 7.2.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

14 %F000-ADGC 1.44E-03 4.89% FIRE IN F000-ADGC - DG01C DIESEL Initiating event - no impact on SAMDA analysis GENERATOR ROOM T-55 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (2 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 15 DGDGR-B-DGB 2.50E-02 4.83% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

16 %F122-T01-U 7.61E-04 4.66% FIRE IN F122-T01-U - F122-T01 Initiating event - no impact on SAMDA analysis Unsuppressed Fires 17 AFTPR1A-TDP01A 3.52E-02 4.26% AFW TDP PP01A FAILS TO RUN FOR > The component associated with this basic event is evaluated in 1HR Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

18 DGDGR-A-DGA 2.50E-02 4.21% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

19 AFMPM2A-MDP02A 3.98E-03 4.19% AFW MDP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.3.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

20 NPXHM-N-SAT02N 1.75E-03 3.54% SAT TR02N UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.11.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

21 %F157-AMCR-1-4 7.57E-07 3.42% FIRE IN F157-AMCR - CCTV FIRE - Initiating event - no impact on SAMDA analysis UNSUPPRESSED - ASD 22 %F157-AMCR-2-4 7.57E-07 3.42% FIRE IN F157-AMCR - FIRE CONTROL Initiating event - no impact on SAMDA analysis PANEL FIRE - UNSUPPRESSED - ASD 23 FWOPH-S-LNG 6.15E-03 3.28% OPERATOR FAILS TO ALINE STARTUP Procedural changes are not in the scope of this SAMDA analysis FEEDWATER PUMP PP07 (LATE PHASE) 24 WOCHM2A-CH02A 4.00E-02 3.27% ECW CHILLER 02A TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.15.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

25 %F100-T15-U 5.39E-04 3.20% FIRE IN F100-T15 - SWITCHGEAR RM - Initiating event - no impact on SAMDA analysis UNSUPPRESSED 26 AFMVC1B-046 5.78E-02 3.05% AFW ISOL. MOV V046 FAILS TO CLOSE The component associated with this basic event is evaluated in Section 7.3.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

27 AFMVO1B-046 5.78E-02 3.05% AFW ISOL. MOV V046 FAILS TO OPEN The component associated with this basic event is evaluated in Section 7.3.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-56 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (3 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 28 COMBINATION_2-F 5.91E+01 2.90% HEP dependency factor for AFOPH-S-ALT- Procedural changes are not in the scope of this SAMDA analysis LT, FWOPH-S-LNG, RCOPH-S-SDSL 29 PFLOOP-NO-SI 2.00E-03 2.83% CONDITIONAL LOOP AFTER Conditional LOOP event - no impact on SAMDA analysis INITIATORS WHICH DO NOT INITIATE AN SI SIGNAL 30 WOCHM2B-CH02B 4.00E-02 2.82% ECW CHILLER 02B TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

31 AFTPR1B-TDP01B 3.52E-02 2.78% AFW TDP PP01B FAILS TO RUN FOR > The component associated with this basic event is evaluated in 1HR Section 7.3.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

32 DGDGM-B-DGB 1.44E-02 2.75% DG 01B UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

33 VOHVM2A-HV33A 2.50E-03 2.62% CUBICLE COOLER HV33A UAVAILABLE The component associated with this basic event is evaluated in DUE TO T&M Section 7.15.21. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

34 FWOPH-S-ERY 7.77E-03 2.54% Operate Fails to Align Startup Feedwater Procedural changes are not in the scope of this SAMDA analysis pump PP07 (Early Phase) 35 SXFLP-S-FT0123AB 5.57E-05 2.41% CCF OF ALL ESW DERIS FILTERS DUE The component associated with this basic event is evaluated in TO PLUGGING Section 7.17.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

36 DGDGM-A-DGA 1.44E-02 2.36% DG 01A UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

37 DGDGKQ4-DG01ABCD 5.95E-05 2.29% 4/4 CCF OF EDG 01A/01B/01C/01D FAIL The components associated with this basic event are evaluated in TO RUN Sections 7.1.1 through 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

38 COMBINATION_11-F 1.98E+01 2.24% HEP dependency factor for FWOPH-S-ERY, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 39 DCBTM-B-BT01B 2.72E-03 2.10% CLASS 1E 125V DC BATTERY BT01B The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-57 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (4 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 40 COMBINATION_3-F 6.51E+00 2.10% HEP dependency factor for AFOPH-S-ALT- Procedural changes are not in the scope of this SAMDA analysis LT, RCOPH-S-SDSL 41 BF_F120-AGAC_F120-AGAD 1.20E-03 1.92% BARRIER FAILURE BETWEEN FIRE The component associated with this basic event is evaluated in COMPS F120-AGAC & F120-AGAD Section 7.4.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

42 DGDGR-D-DGD 2.50E-02 1.90% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01D Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

43 AFMPM2B-MDP02B 3.98E-03 1.84% AFW MDP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

44 %F157-AMCR-5-4 4.04E-07 1.82% FIRE IN F157-AMCR - TRANSIENT W/C Initiating event - no impact on SAMDA analysis FIRE - UNSUPPRESSED - ASD 45 %F078-A19A 3.93E-04 1.81% FIRE IN F078-A19A - CORRIDOR Initiating event - no impact on SAMDA analysis 46 %F100-A08C-U 5.02E-04 1.79% FIRE IN F100-A08C - N1E DC & IP Initiating event - no impact on SAMDA analysis EQUIPMENT RM C - UNSUPPRESSED 47 %F000-AFHL 1.75E-03 1.76% FIRE IN F000-AFHL - FUEL HANDLING Initiating event - no impact on SAMDA analysis LOWER AREA 48 %F120-AGAC 2.86E-04 1.71% FIRE IN F120-AGAC - GENERAL ACCESS Initiating event - no impact on SAMDA analysis AREA-120' C 49 %F067-T02-U 7.75E-05 1.68% FIRE IN F067-T02 - UNDERGROUND Initiating event - no impact on SAMDA analysis COMMON TUNNEL - UNSUPPRESSED 50 NPXHM-M-SAT02M 1.75E-03 1.63% SAT TR02M UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.11.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

51 DGDGR-C-DGC 2.50E-02 1.57% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01C Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

52 %F157-AMCR-6-4 3.43E-07 1.55% FIRE IN F157-AMCR - CABLE W/C FIRE - Initiating event - no impact on SAMDA analysis UNSUPPRESSED - ASD 53 %F120-A09D 2.15E-04 1.53% FIRE IN F120-A09D - ELECTRICAL Initiating event - no impact on SAMDA analysis PENETRATION ROOM D 54 %F000-ADGD-U 3.63E-04 1.52% FIRE IN F000-ADGD - DG01D ROOM - Initiating event - no impact on SAMDA analysis UNSUPPRESSED FIRES T-58 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (5 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 55 PFHBC1A-SW01A-A2 6.66E-03 1.48% PCB SW01A-A2 OF 4.16KV SWGR SW01A The component associated with this basic event is evaluated in FAILS TO CLOSE Section 7.11.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

56 WOCHWQ4-CH01A/2A/1B/2B 3.86E-05 1.48% 4/4 CCF OF ECW CHILLERS 1A/2A/1B/2B The components associated with this basic event are evaluated in FAIL TO START Sections 7.15.3 through 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

57 DATGM-S-AACTG 5.00E-02 1.47% AAC DG UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.2.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

58 %F078-A52D-U 3.48E-04 1.45% FIRE IN F078-A52D - 480V N1E MCC RM - Initiating event - no impact on SAMDA analysis UNSUPPRESSED 59 %F120-A05C-U 2.98E-04 1.42% FIRE IN F120-A05C - ELECTRICAL Initiating event - no impact on SAMDA analysis EQUIPMENT RM C - UNSUPPRESSED 60 SXMPM2B-PP02B 2.64E-02 1.40% ESW PUMP PP02B UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.17.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

61 DCBTM-A-BT01A 2.72E-03 1.39% CLASS 1E 125V DC BATTERY BT01A The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.8.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

62 WOCHR1A-CH01A 7.32E-04 1.37% FAILS TO RUN ECW CHILLER CH01A The component associated with this basic event is evaluated in FOR 24 HOURS Section 7.15.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

63 %F120-AGAD-U 2.42E-04 1.29% FIRE IN F120-AGAD - GENERAL ACCESS Initiating event - no impact on SAMDA analysis AREA-120' D - UNSUPPRESSED 64 SXMPM2A-PP02A 2.64E-02 1.29% ESW PUMP PP02A UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T/M Section 7.17.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

65 %F100-AEEB-U 3.02E-04 1.28% FIRE IN F100-AEEB - 480V CLASS 1E Initiating event - no impact on SAMDA analysis MCC 01B RM - UNSUPPRESSED 66 %F073-T11 1.61E-03 1.21% FIRE IN F073-T11 - SWITCHGEAR AREA Initiating event - no impact on SAMDA analysis 67 %F120-A09C-U 1.96E-05 1.18% FIRE IN F120-A09C - ELECTRICAL Initiating event - no impact on SAMDA analysis PENETRATION RM C - UNSUPPRESSED T-59 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (6 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 68 SIVVT1B-V959 9.22E-05 1.16% SI PUMP PP02B/D MINI. FLOW LINE The component associated with this basic event is evaluated in MANUAL VALVE 959 FAILS TO REMAIN Section 7.16.9. A design change would be expected to cost more OPEN than the total maximum cost reduction and, as a result, not provide a positive benefit.

69 AFPVKQ4-TP01A/B/MP02A/B 1.11E-05 1.16% 4/4 CCF OF AFW TDP01A/B/MDP02A/B The components associated with this basic event are evaluated in FAIL TO RUN Sections 7.3.3 through 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

70 PFHBC1B-SW01B-A2 6.66E-03 1.15% PCB SW01B-A2 OF 4.16KV SWGR SW01B The component associated with this basic event is evaluated in FAILS TO CLOSE Section 7.11.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

71 VOHVM1B-HV33B 2.50E-03 1.14% CUBICLE COOLER HV33B UAVAILABLE The component associated with this basic event is evaluated in DUE TO T&M Section 7.15.22. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

72 PFLOOP-SI 2.00E-02 1.13% CONDITIONAL LOOP AFTER Conditional LOOP event - no impact on SAMDA analysis INITIATORS WHICH INITIATE AN SI SIGNAL 73 %F055-AGAC-U 2.05E-04 1.04% FIRE IN F055-AGAC - GENERAL ACCESS Initiating event - no impact on SAMDA analysis AREA-55' C - UNSUPPRESSED 74 DGDGM-D-DGD 1.44E-02 1.02% DG 01D UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

75 WOCHS1B-CH01B 1.30E-02 1.01% FAILS TO START ECW CHILLER CH01B The component associated with this basic event is evaluated in Section 7.15.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

76 %F078-AGAC-U 1.39E-04 1.01% FIRE IN F078-AGAC - GENERAL ACCESS Initiating event - no impact on SAMDA analysis AREA-78' C - UNSUPPRESSED 77 WOCHS2A-CH02A 1.30E-02 1.01% FAILS TO START ECW CHILLER CH02A The component associated with this basic event is evaluated in Section 7.15.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

78 %F000-ACV 6.04E-04 1.00% FIRE IN F000-ACV - CVCS ACCESS AREA Initiating event - no impact on SAMDA analysis 79 %F100-AGAC 1.26E-04 0.97% FIRE IN F100-AGAC - GENERAL ACCESS Initiating event - no impact on SAMDA analysis AREA 80 %F078-AEEB-U 1.36E-04 0.96% FIRE IN F078-AEEB - CLASS 1E Initiating event - no impact on SAMDA analysis SWITCHGEAR 01B ROOM -

UNSUPPRESSED T-60 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (7 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 81 WOCHS1A-CH01A 1.30E-02 0.96% FAILS TO START ECW CHILLER CH01A The component associated with this basic event is evaluated in Section 7.15.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

82 WOMPM2A-PP02A 1.42E-02 0.91% ECW PP02A TRAIN UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.18.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

83 BF_F078-AGAC_F078-AGAD 9.80E-03 0.90% BARRIER FAILURE BETWEEN FIRE The component associated with this basic event is evaluated in COMPS F078-AGAC & F078-AGAD Section 7.4.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

84 %F137-A05D 1.55E-04 0.90% FIRE IN F137-A05D - PCS RM Initiating event - no impact on SAMDA analysis 85 ASD-CDF-MCA 1.00E-02 0.87% FAILURE OF ALTERNATE SHUTDOWN This event represents operator actions and procedural changes are AFTER MCR EVACUATION (CORE not in the scope of this SAMDA analysis DAMAGE) - MC EVENT 86 %F000-TB-GTRN 3.08E-02 0.86% FIRE IN F000-TB-GTR - TB FIRES Initiating event - no impact on SAMDA analysis LEADING TO GTRN 87 WOCHS2B-CH02B 1.30E-02 0.86% FAILS TO START ECW CHILLER CH02B The component associated with this basic event is evaluated in Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

88 CDOPH-S-ALIGN 9.43E-03 0.86% Operator Fails to Align the Manual Valves and Procedural changes are not in the scope of this SAMDA analysis start CD pumps for Hotwell Makeup 89 VOHVS2A-HV33A 8.29E-04 0.85% FAILS TO START OF MAFP ROOM A The component associated with this basic event is evaluated in CUBICLE COOLER HV33A Section 7.15.21. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

90 RCPVO-A-200 3.54E-03 0.84% POSRV V200 FAILS TO OPEN The component associated with this basic event is evaluated in (HARDWARE FAIL) Section 7.12.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

91 RCPVO-C-201 3.54E-03 0.84% POSRV V201 FAILS TO OPEN The component associated with this basic event is evaluated in (HARDWARE FAIL) Section 7.12.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

92 WOMPM2B-PP02B 1.42E-02 0.84% ECW PP02B TRAIN UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.18.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-61 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (8 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 93 DGDGM-C-DGC 1.44E-02 0.83% DG 01C UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.1.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

94 %F120-A01D 2.62E-05 0.79% FIRE IN F120-A01D - PIPING CABLE Initiating event - no impact on SAMDA analysis AREA 95 %F157-ACPX-U 9.36E-05 0.75% FIRE IN F157-ACPX - COMPUTER ROOM - Initiating event - no impact on SAMDA analysis UNSUPPRESSED 96 %F000-ACVU-U 2.13E-04 0.75% FIRE IN F000-ACVU - CVCS SYSTEM Initiating event - no impact on SAMDA analysis AREA - UNSUPPRESSED 97 COMBINATION_26-F 1.78E+01 0.74% HEP dependency factor for CVOPH-S- Procedural changes are not in the scope of this SAMDA analysis RCPSEAL, RCOPH-S-RCPTRIP 98 CVOPH-S-RCPSEAL 5.64E-02 0.74% Operator Fails to Operate Auxiliary Charging Procedural changes are not in the scope of this SAMDA analysis Pump for RCP Seal Injection 99 %F157-A01D-U 1.69E-04 0.74% FIRE IN F157-A01D - I & C EQUIP. RM - Initiating event - no impact on SAMDA analysis UNSUPPRESSED 100 AFTPS1A-TDP01A 6.49E-03 0.73% AFW TDP PP01A FAILS TO START The component associated with this basic event is evaluated in Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

101 %F120-A15B-U 1.73E-04 0.72% FIRE IN F120-A15B - 480V CLASS 1E MCC Initiating event - no impact on SAMDA analysis 03B RM - UNSUPPRESSED 102 %F078-A05C 3.24E-04 0.71% FIRE IN F078-A05C - CHANNEL-C DC & Initiating event - no impact on SAMDA analysis IP EQUIP RM 103 PGOPH-S-LC01B 1.00E+00 0.71% OPERATOR FAILS TO TRANSFER Procedural changes are not in the scope of this SAMDA analysis SOURCE FROM LC01A TO LC01B 104 COMBINATION_27-F 1.00E+00 0.70% HEP dependency factor for RCOPH-S- Procedural changes are not in the scope of this SAMDA analysis RCPTRIP, PGOPH-S-LC01B 105 WTMPM-B-PP02 1.42E-02 0.66% TGBCCW PUMP P02 TRAIN The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.13.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

106 DGDGL-B-DGB 3.78E-03 0.65% DG B FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

107 IPINM-B-IN01B 2.00E-03 0.62% CLASS 1E 120V AC INVERTER IN01B The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-62 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6c (9 of 9)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 108 SIMPM2B-PP02D 3.88E-03 0.62% SI PUMP 4 (PP02D) UNAVAILABLE DUE The component associated with this basic event is evaluated in TO T&M Section 7.16.8. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

109 AFTPM1A-TDP01A 5.39E-03 0.60% AFW TDP PP01A UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T/M Section 7.3.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

110 IPINM-A-IN01A 2.00E-03 0.60% CLASS 1E 120V AC INVERTER IN01A The component associated with this basic event is evaluated in UNAVAILABLE DUE TO T&M Section 7.9.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

111 %F078-A02D 8.39E-05 0.58% FIRE IN F078-A02D - CLASS 1E Initiating event - no impact on SAMDA analysis SWITCHGEAR 01D RM 112 %F078-A25A-U 1.27E-04 0.57% FIRE IN F078-A25A - CLASS 1E Initiating event - no impact on SAMDA analysis SWITCHGEAR 01A RM - UNSUPPRESSED 113 DGSQA-B-LOADSQ 3.33E-03 0.56% LOAD SEQUNCER A FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

114 SIMPM1B-PP02B 3.88E-03 0.56% SI PUMP PP02B UNAVAILABLE DUE TO The component associated with this basic event is evaluated in T&M Section 7.16.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

115 DGDGL-A-DGA 3.78E-03 0.55% DG A FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

116 %F157-A25C-U 1.69E-04 0.53% FIRE IN F157-A25C - I & C EQUIP. RM - Initiating event - no impact on SAMDA analysis UNSUPPRESSED 117 %F137-ANEA 6.92E-04 0.53% FIRE IN F137-ANEA - ELECTRICAL Initiating event - no impact on SAMDA analysis EQUIPMENT ROOM 118 WOCHKQ4-CH01A/1B/2A/2B 4.86E-06 0.53% 4/4 CCF OF ECW CHILLERS 1A/2A/1B/2B The components associated with this basic event are evaluated in FAIL TO RUN Section 7.15.3 through 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

119 BF_F100-A06D_F100-AGAC 9.80E-03 0.52% BARRIER FAILURE BETWEEN FIRE The component associated with this basic event is evaluated in COMPS F100-A06D & F100-AGAC Section 7.4.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

120 PPSO-OS-PPS 1.20E-06 0.50% CCF OF PPS OPERATING SYSTEM SOFTWARE T-63 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6d (1 of 5)

List of Basic Events from APR1400 PRA CDF Importance Analysis (LPSD Internal Events)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 1 %SO 2.90E-03 49.10% RCS Overdraining due to SCS Initiating event - no impact on SAMDA analysis 2 BE-RATE-OT-05 6.67E-01 43.47% Conv. factor (Outage-yr -> Cal. yr, Quantification factor - no impact on SAMDA analysis 1/(18mon/12mon)) for Demand Failure during POS 05 3 HR-FB-SOP05-01 3.49E-04 36.69% Operator Fails to Feed during SO POS 5 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 4 COMBINATION_1-LP 1.44E+02 36.46% HEP dependency factor for HR-RS-SOP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-SOP05-01 5 HR-RS-SOP05 6.76E-03 36.46% Operator Fails to Restore SCS during SO POS Procedural changes are not in the scope of this SAMDA analysis 5

6 BE-RATE-P03A 3.36E-04 16.27% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS03A duration 7 BE-RATE-P05 1.23E-03 15.61% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS5 duration 8 %SL 2.90E-01 8.83% Failure to Maintain Water Level at Reduced Initiating event - no impact on SAMDA analysis Inventory 9 HR-FB-SLP05-01 3.49E-04 6.77% Operator Fails to Feed during SL POS 5 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 10 COMBINATION_8-LP 1.44E+02 6.72% HEP dependency factor for HR-RS- Procedural changes are not in the scope of this SAMDA analysis SLP05,HR-FB-SLP05-01 11 HR-RS-SLP05 6.76E-03 6.72% Operator Fails to Restore SCS during SL POS Procedural changes are not in the scope of this SAMDA analysis 5

12 BE-RATE-OT-11 6.67E-01 5.64% Conv. factor (Outage-yr -> Cal. yr, Quantification factor - no impact on SAMDA analysis 1/(18mon/12mon)) for Demand Failure during POS 11 13 SISPP-S-IRWST 1.22E-05 5.43% CCF OF IRWST SUMPS DUE TO The component associated with this basic event is evaluated in PLUGGING Section 7.16.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

14 DGDGR-A-DGA 2.50E-02 5.40% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

15 DGDGR-B-DGB 2.50E-02 5.39% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-64 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6d (2 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 16 BE-RATE-P10 6.26E-03 5.32% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS10 duration 17 %SL1 1.60E-01 4.90% Small LOCA at Reduced Inventory Initiating event - no impact on SAMDA analysis 18 %TC 2.34E-04 4.48% Total Loss of Component Cooling Water Initiating event - no impact on SAMDA analysis 19 %TS 2.34E-04 4.48% Total Loss of Essential Service Water Initiating event - no impact on SAMDA analysis 20 %LPSW 6.39E-02 4.44% Loss of offsite power of Switchyard-centered Initiating event - no impact on SAMDA analysis for LPSD 21 PPSO-AP-LC 1.20E-05 4.13% CCF OF PPS LC APPLICATION The component associated with this basic event is evaluated in SOFTWARE Section 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

22 %PL 3.66E-03 4.07% STUCK OPEN OF POSRV Initiating event - no impact on SAMDA analysis 23 BE-RATE-OT-02 6.67E-01 4.07% Conv. factor (Outage-yr -> Cal. yr, Quantification factor - no impact on SAMDA analysis 1/(18mon/12mon)) for Demand Failure during POS 02 24 COMBINATION_2-LP 1.93E+01 4.05% HEP dependency factor for HR-MI-SOP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-SOP05-02 25 HR-FB-SOP05-02 2.72E-03 4.05% Operator Fails to Feed during SO POS 5 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 26 HR-MI-SOP05 7.18E-04 4.05% Operator Fails to Isolate and Makeup SO at Procedural changes are not in the scope of this SAMDA analysis POS 5 27 COMBINATION_4-LP 9.41E+01 3.89% HEP dependency factor for HR-MI-SOP11, Procedural changes are not in the scope of this SAMDA analysis HR-FB-SOP11-02 28 HR-FB-SOP11-02 5.37E-04 3.89% Operator Fails to Feed during SO POS 11 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 29 HR-MI-SOP11 7.18E-04 3.89% Operator Fails to Isolate and Makeup SO at Procedural changes are not in the scope of this SAMDA analysis POS 11 30 BE-RATE-P06 4.01E-03 3.88% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS6 duration 31 HR-FB-JLP05-01 5.37E-04 3.88% Operator Fails to Feed during JL POS 5 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 32 COMBINATION_19-LP 9.41E+01 3.84% HEP dependency factor for HR-RS-JLP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-JLP05-01 33 HR-RS-JLP05 6.76E-03 3.84% Operator Fails to Restore SCS during JL POS Procedural changes are not in the scope of this SAMDA analysis 5

34 %SL2 3.50E-02 3.81% Small LOCA above Reduced Inventory Initiating event - no impact on SAMDA analysis 35 %LPWE 3.67E-02 3.74% Loss of offsite power of Weather-related for Initiating event - no impact on SAMDA analysis LPSD T-65 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6d (3 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 36 %LPPL 5.28E-02 3.48% Loss of offsite power of Plant-centered for Initiating event - no impact on SAMDA analysis LPSD 37 %S1 1.40E-01 3.46% Loss of SCS (S1) Initiating event - no impact on SAMDA analysis 38 DATGR-S-AACTG 1.57E-01 2.08% FAILS TO RUN AAC GAS TURBINE The component associated with this basic event is evaluated in GENERATOR Section 7.2.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

39 HR-FB-JLP10-01 5.37E-04 1.50% Operator Fails to Feed during JL POS 10 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 40 BE-RATE-P11 9.66E-04 1.48% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS11 duration 41 COMBINATION_16-LP 9.41E+01 1.46% HEP dependency factor for HR-RS-JLP10, Procedural changes are not in the scope of this SAMDA analysis HR-FB-JLP10-01 42 HR-RS-JLP10 2.08E-03 1.46% Operator Fails to Restore SCS during JL POS Procedural changes are not in the scope of this SAMDA analysis 10 43 HR-RS-S1P05 4.18E-01 1.44% Operator Fails to Restore SCS during S1 POS Procedural changes are not in the scope of this SAMDA analysis 5

44 COMBINATION_21-LP 1.00E+00 1.39% HEP dependency factor for HR-RS-S1P05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-S1P05 45 HR-FB-S1P05 3.49E-04 1.39% Operator Fails to Feed during S1 POS 5 Procedural changes are not in the scope of this SAMDA analysis 46 BE-RATE-P03B 2.74E-03 1.38% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS03B duration 47 %KV 3.50E-02 1.19% Loss of Class 1E 4.16KV Initiating event - no impact on SAMDA analysis 48 HR-FB-JLP06-01 2.72E-03 1.12% Operator Fails to Feed during JL POS 6 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 49 COMBINATION_26-LP 1.93E+01 0.97% HEP dependency factor for HR-RS-JLP06, Procedural changes are not in the scope of this SAMDA analysis HR-FB-JLP06-01 50 HR-RS-JLP06 2.08E-03 0.97% Operator Fails to Restore SCS during JL POS Procedural changes are not in the scope of this SAMDA analysis 6

51 BE-RATE-P4B 1.49E-03 0.97% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS4B duration 52 RAC-LXP10-AC-WE 4.78E-01 0.93% Recovery Offsite Power within 3.0hr at SBO This event represents characteristics of the site at which the plant POS10 AC WE will be located and the probability is based on generic industry data. Design changes to affect the risk from site characteristics are not applicable to the SAMDA analysis and this event is not considered further.

53 %LPGR 1.15E-02 0.89% Loss of offsite power of Grid-related for LPSD Initiating event - no impact on SAMDA analysis T-66 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6d (4 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 54 DGDGL-A-DGA 3.78E-03 0.79% DG A FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

55 DGDGL-B-DGB 3.78E-03 0.79% DG B FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

56 BE-RATE-P13 2.44E-03 0.78% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS13 duration 57 %ES 1.86E-02 0.77% Loss of Essential Service Water Initiating event - no impact on SAMDA analysis 58 COMBINATION_9-LP 1.93E+01 0.75% HEP dependency factor for HR-MI-SLP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-SLP05-02 59 HR-FB-SLP05-02 2.72E-03 0.75% Operator Fails to Feed during SL POS 5 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 60 HR-MI-SLP05 7.18E-04 0.75% Operator Fails to Isolate and Makeup SL at Procedural changes are not in the scope of this SAMDA analysis POS 5 61 WOCHKQ4-CH01A/1B/2A/2B 4.86E-06 0.73% 4/4 CCF OF ECW CHILLERS 1A/2A/1B/2B The components associated with this basic event are evaluated in FAIL TO RUN Section 7.15.3 through 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

62 %JL 5.00E-03 0.69% Unrecoverable LOCA Initiating event - no impact on SAMDA analysis 63 DGSQA-B-LOADSQ 3.33E-03 0.69% LOAD SEQUNCER A FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

64 DGSQA-A-LOADSQ 3.33E-03 0.69% LOAD SEQUNCER A FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

65 %S2 2.20E-02 0.66% Loss of SCS (S2) Initiating event - no impact on SAMDA analysis 66 DATGM-S-AACTG 5.00E-02 0.63% AAC DG UNAVAILABLE DUE TO T&M The component associated with this basic event is evaluated in Section 7.2.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

67 DGDGS-A-DGA 2.89E-03 0.60% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-67 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6d (5 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 68 DGDGS-B-DGB 2.89E-03 0.60% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

69 COMBINATION_13-LP 9.41E+01 0.56% HEP dependency factor for HR-MI-SLP11, Quantification factor - no impact on SAMDA analysis HR-FB-SLP11-02 70 HR-FB-SLP11-02 5.37E-04 0.56% Operator Fails to Feed during SL POS 11 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 71 HR-MI-SLP11 7.18E-04 0.56% Operator Fails to Isolate and Makeup SL at Procedural changes are not in the scope of this SAMDA analysis POS 11 72 SIMPWQ4-CSP1A/B/SCP1A/B 4.14E-06 0.56% 4/4 CCF OF CSP PP01A/PP01B AND SCP The components associated with this basic event are evaluated in PP01A/PP01B FAIL TO START Section 7.6.1, 7.6.2, 7.24.1, and 7.24.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

73 DGDGKQ4-DG01ABCD 5.95E-05 0.54% 4/4 CCF OF EDG 01A/01B/01C/01D FAIL The components associated with this basic event are evaluated in TO RUN Sections 7.1.1 through 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

74 SIMPR2A-PP02C 2.83E-03 0.53% FAILS TO RUN SI PUMP PP02C The component associated with this basic event is evaluated in Section 7.16.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

75 BE-RATE-P12A 3.07E-04 0.52% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS12A duration 76 COMBINATION_17-LP 9.41E+01 0.50% HEP dependency factor for HR-MI-JLP10, Procedural changes are not in the scope of this SAMDA analysis HR-FB-JLP10-02 77 HR-FB-JLP10-02 5.37E-04 0.50% Operator Fails to Feed during JL POS 10 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 78 HR-MI-JLP10 7.18E-04 0.50% Operator Fails to Isolate and Makeup JL at Procedural changes are not in the scope of this SAMDA analysis POS 10 79 RAC-LXP10-AC-SW 1.50E-01 0.50% Recovery Offsite Power within 3.0hr at SBO This event represents characteristics of the site at which the plant POS10 AC SW will be located and the probability is based on generic industry data. Design changes to affect the risk from site characteristics are not applicable to the SAMDA analysis and this event is not considered further.

T-68 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6e (1 of 6)

List of Basic Events from APR1400 PRA CDF Importance Analysis (LPSD Internal Flooding Events)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 1 BE-RATE-P10 6.26E-03 75.8% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS10 duration 2 DGDGR-A-DGA 2.50E-02 32.7% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

3 %IE-078-44B-FP-X-LP 3.42E-04 23.3% MAJ BRK IN FP PIPING IN B QUAD 78 FT Initiating event - no impact on SAMDA analysis EL RM 078-A44B AND OTHER B QUAD RMS (LPSD) 4 %IE-078-19B-FP-X-LP 3.49E-04 19.1% MAJ BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A19B AND OTHER B QUAD RMS (LPSD) 5 %IE-055-22A-IW-S-LP 2.08E-05 16.1% BREAK OF UNISOLABLE IW PIPING IN A Initiating event - no impact on SAMDA analysis QUAD 55 FT EL RM 055-A22A (LPSD) 6 BE-RATE-P05 1.23E-03 16.0% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS5 duration 7 HR-RS-S2P05 4.18E-01 15.1% Operator Fails to Restore SCS during S2 POS Procedural changes are not in the scope of this SAMDA analysis 5

8 DGDGR-D-DGD 2.50E-02 9.5% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01D Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

9 PFHBO1A-SW01A-H2 6.66E-03 8.7% PCB SW01A-H2 4.16KV SWGR SW01A The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 10 AFOPH-1-ISO-FL 1.00E+00 8.3% Operator fails to isolate major break of AF Procedural changes are not in the scope of this SAMDA analysis piping in TDAFP room.

11 %IE-078-15D-AF-X-LP 1.98E-05 8.3% MAJ BRK (>3200 GPM) IN AF PIPING IN D Initiating event - no impact on SAMDA analysis QUAD 78 FT EL RM 078-A15D (LPSD) 12 WOOPH-B-1/2B 2.06E-02 7.9% OPERATOR FAILS TO OPERATE ECW Procedural changes are not in the scope of this SAMDA analysis PUMPS PP01/2B 13 %IE-137-13B-FP-X-LP 1.71E-05 7.0% MAJ BRK (> 1180 GPM) OF FP PIPING IN Initiating event - no impact on SAMDA analysis B QUAD 137 FT EL RM 137-A13B &

OTHERS (LPSD) 14 %IE-078-19B-FP-M-LP 1.34E-04 6.8% MOD BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A19B AND OTHER B QUAD RMS (LPSD)

T-69 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6e (2 of 6)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 15 %IE-078-01D-FP-X-LP 1.71E-04 5.3% MAJ BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A01D AND OTHER B QUAD RMS (LPSD) 16 WOCHS2B-CH02B 1.30E-02 5.0% FAILS TO START ECW CHILLER CH02B The component associated with this basic event is evaluated in Section 7.15.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

17 DGDGL-A-DGA 3.78E-03 4.9% DG A FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

18 DGSQA-A-LOADSQ 3.33E-03 4.3% LOAD SEQUNCER A FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

19 DGDGS-A-DGA 2.89E-03 3.8% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

20 FPOPH-2-ISO-FL 8.00E-03 3.3% Operator fails to isolate FP break with between Procedural changes are not in the scope of this SAMDA analysis 20 and 40 minutes available 21 BE-RATE-P06 4.01E-03 3.2% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS6 duration 22 %IE-100-10B-FP-X-LP 5.71E-05 3.0% MAJ BRK (>1445 GPM) IN FP PIPING IN B Initiating event - no impact on SAMDA analysis QUAD 100 FT EL RM 100-A10B (LPSD) 23 VDHVL-A-HV12A 2.28E-03 3.0% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV12A FOR 1HR Section 7.15.11. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

24 VDHVL-A-HV13A 2.28E-03 3.0% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV13A FOR 1HR Section 7.15.16. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

25 PFHBO2B-SW01D-G2 6.66E-03 2.5% PCB SW01D-G2 4.16KV SWGR SW01D The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

26 DGDGR-B-DGB 2.50E-02 2.4% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-70 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6e (3 of 6)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 27 FPOPH-1-ISO-FL 9.48E-03 2.0% Operator fails to isolate FP break with less Procedural changes are not in the scope of this SAMDA analysis than 20 minutes available 28 HR-FB-S2P05 3.49E-04 1.8% Operator Fails to Feed during S2 POS 5 Procedural changes are not in the scope of this SAMDA analysis 29 %IE-055-21B-SI-M-LP 2.05E-07 1.7% MOD BRK (500 - 3000 GPM) OF SI PIPING Initiating event - no impact on SAMDA analysis IN B QUAD 55-FT EL RM 055-A21B (LPSD) 30 SXCTM-2B-CT02B 4.00E-03 1.5% SXCT CT02B UNAVAILABLE DUE TO T&M 31 %IE-078-01D-FP-M-LP 5.51E-05 1.5% MOD BRK (VARIOUS GPM) IN FP PIPING Initiating event - no impact on SAMDA analysis IN 078-A01D AND OTHER B QUAD RMS (LPSD) 32 BE-RATE-P03A 3.36E-04 1.5% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS03A duration 33 VGAHS2B-AH02B 3.86E-03 1.5% FAILS TO START EWS PUMP ROOM II.

SUPPLY FAN AH02B 34 DGDGL-D-DGD 3.78E-03 1.4% DG D FAILS TO LOAD AND RUN The component associated with this basic event is evaluated in DURING 1ST 1HR OF OPERATION Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

35 BE-RATE-P03B 2.74E-03 1.3% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS03B duration 36 DGSQA-D-LOADSQ 3.33E-03 1.3% LOAD SEQUNCER D FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

37 CCMVO-A-191 9.63E-04 1.2% CCW MOV V191 FAILS TO OPEN 38 %IE-137-29B-FP-M-LP 2.66E-06 1.2% MOD BRK (1690 - 2500 GPM) OF FP Initiating event - no impact on SAMDA analysis PIPING IN B QUAD 137 FT EL RM 137-A29B (LPSD) 39 BE-RATE-P4B 1.49E-03 1.2% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS4B duration 40 HR-SG-S2P03B 6.06E-04 1.2% Operator Fails to Remove Steam during S2 at Procedural changes are not in the scope of this SAMDA analysis POS 3B 41 HR-RS-S2P03B 2.88E-01 1.2% Operator Fails to Restore SCS during S2 POS Procedural changes are not in the scope of this SAMDA analysis 3B 42 COMBINATION_150-LP 8.34E+01 1.1% HEP dependency factor for HR-RS-S2P03B, Procedural changes are not in the scope of this SAMDA analysis HR-SG-S2P03B 43 DGDGS-D-DGD 2.89E-03 1.1% FAILS TO START OF EMERGENCY The component associated with this basic event is evaluated in DIESEL GENERATOR DG01D Section 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-71 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6e (4 of 6)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 44 HR-FB-S2P10 3.49E-04 1.1% Operator Fails to Feed during S2 POS 10 Procedural changes are not in the scope of this SAMDA analysis 45 SIMPR2B-PP02D 2.83E-03 1.1% FAILS TO RUN SI PUMP PP02D The component associated with this basic event is evaluated in Section 7.16.8. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

46 VDHVS-A-HV12A 8.29E-04 1.1% FAILS TO START EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV12A Section 7.15.11. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

47 VDHVS-A-HV13A 8.29E-04 1.1% FAILS TO START EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV13A Section 7.15.15. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

48 SIMPR1A-PP02A 2.83E-03 1.1% FAILS TO RUN SI PUMP PP02A The component associated with this basic event is evaluated in Section 7.16.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

49 VOHVM2B-HV32B 2.50E-03 0.9% CUBICLE COOLER HV32B UAVAILABLE DUE TO T&M 50 WOCHR1A-CH01A 7.32E-04 0.9% FAILS TO RUN ECW CHILLER CH01A The component associated with this basic event is evaluated in FOR 24 HOURS Section 7.15.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

51 %IE-120-11B-FP-X-LP 1.79E-05 0.9% MAJ BRK (>1180 GPM) OF FP PIPING IN B Initiating event - no impact on SAMDA analysis QUAD 120 FT EL RM 120-A11B OR 120-A13B (LPSD) 52 %IE-100-20A-FP-X-LP 3.35E-04 0.9% MAJ BRK OF FP PIPING IN A QUAD 100 Initiating event - no impact on SAMDA analysis FT EL RM 100-A20A AND OTHERS (LPSD) 53 SXCTS-2B-CT02B 2.32E-03 0.9% SX CT02B FANS (ANY 1 OF 3) FAIL TO START 54 HR-SG-S2P03A 6.06E-04 0.9% Operator Fails to Remove Steam during S2 at Procedural changes are not in the scope of this SAMDA analysis POS 3A 55 VDHVL-D-HV12D 2.28E-03 0.9% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV12D FOR 1HR Section 7.15.14. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

56 VDHVL-D-HV13D 2.28E-03 0.9% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in COOLER HV13D FOR 1HR Section 7.15.18. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-72 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6e (5 of 6)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 57 COMBINATION_354-LP 1.04E+03 0.8% HEP dependency factor for HR-RS-S2P05, Procedural changes are not in the scope of this SAMDA analysis FPOPH-2-ISO-FL,HR-FB-S2P05 58 HR-RS-S2P03A 8.20E-01 0.7% Operator Fails to Restore SCS during S2 POS Procedural changes are not in the scope of this SAMDA analysis 3A 59 COMBINATION_175-LP 8.34E+01 0.7% HEP dependency factor for HR-RS-S2P03A, Procedural changes are not in the scope of this SAMDA analysis HR-SG-S2P03A 60 HR-FB-S2P06 3.49E-04 0.6% Operator Fails to Feed during S2 POS 6 Procedural changes are not in the scope of this SAMDA analysis 61 PFHBO1B-SW01B-H2 6.66E-03 0.6% PCB SW01B-H2 4.16KV SWGR SW01B The component associated with this basic event is evaluated in FROM UAT FAILS TO OPEN Section 7.11.7. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

62 %IE-078-20B-AF-X-LP 1.43E-06 0.6% MAJ BRK (>690 GPM) IN AF OR AX Initiating event - no impact on SAMDA analysis PIPING IN B QUAD 78 FT EL RM 078-A20B (LPSD) 63 %IE-055-21A-SI-X-LP 3.13E-08 0.6% MAJ BRK (>3000 GPM) OF SI PIPING IN A Initiating event - no impact on SAMDA analysis QUAD 55-FT EL RM 055-A21A (LPSD) 64 DGDGKQ4-DG01ABCD 5.95E-05 0.5% 4/4 CCF OF EDG 01A/01B/01C/01D FAIL The components associated with this basic event are evaluated in TO RUN Sections 7.1.1 through 7.1.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

65 SIMPR1B-SCPP01B 2.83E-03 0.5% FAILS TO RUN SC PUMP 2 PP01B The component associated with this basic event is evaluated in Section 7.24.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

66 CCMPS2B-PP02B 1.36E-03 0.5% FAILS TO START CCW PUMP PP02B The component associated with this basic event is evaluated in Section 7.5.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

67 SXMPS2B-PP02B 1.36E-03 0.5% FAIL TO START ESW PUMP PP02B The component associated with this basic event is evaluated in Section 7.17.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

68 WOMPS2B-PP02B 1.36E-03 0.5% FAILS TO START OF ECW PUMP 02B The component associated with this basic event is evaluated in Section 7.18.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

69 SXFLP-S-FT0123AB 5.57E-05 0.5% CCF OF ALL ESW DERIS FILTERS DUE The component associated with this basic event is evaluated in TO PLUGGING Section 7.17.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

T-73 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6e (6 of 6)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 70 %IE-078-31A-FP-X-LP 2.49E-04 0.5% MAJ BRK (> 3900 GPM) IN FP PIPING IN A Initiating event - no impact on SAMDA analysis QUAD 78 FT EL RM 078-A31A (LPSD) 71 FPOPH-3DEP-ISO-FL 2.93E-03 0.5% Operator fails to isolate major break of FP Procedural changes are not in the scope of this SAMDA analysis piping in 078-A31A before 18-inches of accumulation.

72 COMBINATION_339-LP 3.54E+05 0.5% HEP dependency factor for HR-RS-S2P05, Procedural changes are not in the scope of this SAMDA analysis FPOPH-2-ISO-FL,FPOPH-3DEP-ISO-FL,HR-FB-S2P05 73 PFHBWQ2-SW2OUATAD 6.03E-05 0.5% 2/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW01A/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 74 %IE-100-37B-FP-X-LP 9.94E-05 0.5% MOD BRK OF FP PIPING IN B QUAD 100 Initiating event - no impact on SAMDA analysis FT EL RM 100-A37B AND OTHERS (LPSD) 75 %IE-055-21B-SI-X-LP 2.54E-08 0.5% MAJ BRK (>3000 GPM) OF SI PIPING IN B Initiating event - no impact on SAMDA analysis QUAD 55-FT EL RM 055-A21B (LPSD) 76 SXHVO-2B-074 1.20E-03 0.5% LOSS OF SX CT02B DUE TO FAILURE TO OPEN OF 2B SXCT SUPPLY HOV SX-074 T-74 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6f (1 of 5)

List of Basic Events from APR1400 PRA CDF Importance Analysis (LPSD Internal Fire Events)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 1 BE-RATE-P05 1.23E-03 68.21% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS5 duration 2 HR-FB-KVP05 2.01E-03 32.56% Operator Fails to Feed during KV POS 5 Procedural changes are not in the scope of this SAMDA analysis 3 HR-RS-KVP05 8.43E-01 32.56% Operator Fails to Restore SCS during KV POS Procedural changes are not in the scope of this SAMDA analysis 5

4 COMBINATION_23-LPF 2.58E+01 32.55% HEP dependency factor for HR-RS-KVP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-KVP05 5 %F000-ADGC-LP 4.65E-03 24.51% FIRE IN DIESEL GENERATOR ROOM Initiating event - no impact on SAMDA analysis 6 HR-FB-LPP05 2.01E-03 16.97% Operator Fails to Feed during LP POS 5 Procedural changes are not in the scope of this SAMDA analysis 7 HR-RS-LPP05 8.43E-01 16.96% Operator Fails to Restore SCS during LP POS Procedural changes are not in the scope of this SAMDA analysis 5

8 COMBINATION_24-LPF 2.58E+01 16.96% HEP dependency factor for HR-RS-LPP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-LPP05 9 BE-RATE-P06 4.01E-03 14.52% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS6 duration 10 HR-FB-CCP05 2.01E-03 8.94% Operator Fails to Feed during CC POS 5 Procedural changes are not in the scope of this SAMDA analysis 11 HR-RS-CCP05 8.43E-01 8.94% Operator Fails to Restore SCS during CC POS Procedural changes are not in the scope of this SAMDA analysis 5

12 COMBINATION_47-LPF 2.58E+01 8.94% HEP dependency factor for HR-RS-CCP05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-CCP05 13 HR-RS-S2P05 8.43E-01 8.50% Operator Fails to Restore SCS during S2 POS Procedural changes are not in the scope of this SAMDA analysis 5

14 HR-FB-S2P05 2.01E-03 8.50% Operator Fails to Feed during S2 POS 5 Procedural changes are not in the scope of this SAMDA analysis 15 COMBINATION_43-LPF 2.58E+01 8.50% HEP dependency factor for HR-RS-S2P05, Procedural changes are not in the scope of this SAMDA analysis HR-FB-S2P05 16 BE-RATE-P10 6.26E-03 6.77% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS10 duration 17 BE-RATE-P4B 1.49E-03 5.98% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS4B duration 18 %F137-ANEA-LP 7.34E-04 4.26% FIRE IN ELECTRICAL EQUIPMENT Initiating event - no impact on SAMDA analysis ROOM 19 %F120-AGAC-LP 6.14E-04 4.17% FIRE IN GENERAL ACCESS AREA-120' C Initiating event - no impact on SAMDA analysis 20 HR-FB-KVP06 5.96E-03 3.72% Operator Fails to Feed during KV POS 6 Procedural changes are not in the scope of this SAMDA analysis T-75 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6f (2 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 21 %FK-K01-LP 7.29E-04 3.70% FIRE IN ESW STRUCTURE "A" BUILDING Initiating event - no impact on SAMDA analysis 22 COMBINATION_4-LPF 9.34E+00 3.64% HEP dependency factor for HR-RS-KVP06, Procedural changes are not in the scope of this SAMDA analysis HR-FB-KVP06 23 HR-RS-KVP06 2.69E-02 3.64% Operator Fails to Restore SCS during KV POS Procedural changes are not in the scope of this SAMDA analysis 6

24 HR-FB-JLP06-01 3.03E-03 3.39% Operator Fails to Feed during JL POS 6 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 25 %F055-AGAC-LP 6.26E-04 3.18% FIRE IN GENERAL ACCESS AREA-55' C Initiating event - no impact on SAMDA analysis 26 %F078-A04C-LP 5.26E-04 2.77% FIRE IN MISC. ELECTRICAL EQUIP RM Initiating event - no impact on SAMDA analysis 27 %F078-AGAC-LP 4.94E-04 2.58% FIRE IN GENERAL ACCESS AREA Initiating event - no impact on SAMDA analysis 28 %F078-A19A-LP 4.74E-04 2.54% FIRE IN CORRIDOR Initiating event - no impact on SAMDA analysis 29 PROB-NON-SUPP-MCR 4.65E-02 2.43% PROBABILITY OF NON-SUPPRESSION This event represents operator actions and procedural changes are OF MCR FIRES RESULTING IN MCR not in the scope of this SAMDA analysis EVACUATION 30 %F157-AMCR-LP 1.22E-04 2.36% FIRE IN MAIN CONTROL ROOM Initiating event - no impact on SAMDA analysis 31 COMBINATION_11-LPF 1.75E+01 2.29% HEP dependency factor for HR-MI-JLP06, Procedural changes are not in the scope of this SAMDA analysis HR-FB-JLP06-02 32 HR-FB-JLP06-02 3.03E-03 2.29% Operator Fails to Feed during JL POS 6 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 33 HR-MI-JLP06 2.29E-02 2.29% Operator Fails to Isolate and Makeup JL at Procedural changes are not in the scope of this SAMDA analysis POS 6 34 BE-RATE-P03A 3.36E-04 2.16% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS03A duration 35 %F120-AGAD-LP 6.49E-04 2.12% FIRE IN GENERAL ACCESS AREA-120' D Initiating event - no impact on SAMDA analysis 36 %FD-D01A-LP 4.14E-04 2.10% FIRE IN CCW HEAT EXCHANGER "A" Initiating event - no impact on SAMDA analysis BUILDING 37 %F100-AGAC-LP 2.30E-04 2.06% FIRE IN GENERAL ACCESS AREA Initiating event - no impact on SAMDA analysis 38 %F078-A19B-LP 9.26E-04 2.06% FIRE IN CORRIDOR Initiating event - no impact on SAMDA analysis 39 DGDGR-A-DGA 2.50E-02 2.00% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01A Section 7.1.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

40 %F078-A05C-LP 3.92E-04 1.98% FIRE IN CHANNEL-C DC & IP EQUIP RM Initiating event - no impact on SAMDA analysis 41 HR-FB-LPP06 5.96E-03 1.97% Operator Fails to Feed during LP POS 6 Procedural changes are not in the scope of this SAMDA analysis T-76 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6f (3 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 42 %F000-ACVU-LP 3.43E-04 1.94% FIRE IN CVCS SYSTEM AREA Initiating event - no impact on SAMDA analysis 43 COMBINATION_5-LPF 9.34E+00 1.90% HEP dependency factor for HR-RS-LPP06, Procedural changes are not in the scope of this SAMDA analysis HR-FB-LPP06 44 HR-RS-LPP06 2.69E-02 1.90% Operator Fails to Restore SCS during LP POS Procedural changes are not in the scope of this SAMDA analysis 6

45 %F078-A25A-LP 3.55E-04 1.90% FIRE IN CLASS 1E SWITCHGEAR 01A RM Initiating event - no impact on SAMDA analysis 46 HR-FB-S2P04B 2.01E-03 1.88% Operator Fails to Feed during S2 POS 4B Procedural changes are not in the scope of this SAMDA analysis 47 COMBINATION_39-LPF 2.58E+01 1.88% HEP dependency factor for HR-RS-S2P04B, Procedural changes are not in the scope of this SAMDA analysis HR-FB-S2P04B 48 HR-RS-S2P04B 1.48E-01 1.88% Operator Fails to Restore SCS during S2 POS Procedural changes are not in the scope of this SAMDA analysis 4B 49 AS-CCDP-ST 5.00E-01 1.87% SHORT TERM ALTERNATE SHUTDOWN This event represents operator actions and procedural changes are CCDP EST. (< = 1.5 HRS FOR RS OR <= 3 not in the scope of this SAMDA analysis HRS FOR SG) 50 %F100-AEEA-LP 3.21E-04 1.83% FIRE IN 480V CLASS 1E MCC 01A RM Initiating event - no impact on SAMDA analysis 51 %F120-A05C-LP 3.38E-04 1.81% FIRE IN ELECTRICAL EQUIP. RM Initiating event - no impact on SAMDA analysis 52 HR-FB-KVP04B 2.01E-03 1.67% Operator Fails to Feed during KV POS 4B Procedural changes are not in the scope of this SAMDA analysis 53 COMBINATION_21-LPF 2.58E+01 1.66% HEP dependency factor for HR-RS-KVP04B, Procedural changes are not in the scope of this SAMDA analysis HR-FB-KVP04B 54 HR-RS-KVP04B 3.54E-02 1.66% Operator Fails to Restore SCS during KV POS Procedural changes are not in the scope of this SAMDA analysis 4B 55 %F078-A03C-LP 3.14E-04 1.64% FIRE IN CLASS 1E LOADCENTER 01C RM Initiating event - no impact on SAMDA analysis 56 %F120-A09C-LP 2.46E-04 1.55% FIRE IN ELECTRICAL PENETRATION Initiating event - no impact on SAMDA analysis ROOM (C) 57 DGDGR-B-DGB 2.50E-02 1.38% FAILS TO RUN EMERGENCY DIESEL The component associated with this basic event is evaluated in GENERATOR DG01B Section 7.1.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

58 %F137-AEPA-LP 2.34E-04 1.36% FIRE IN ELECTRICAL PENETRATION Initiating event - no impact on SAMDA analysis ROOM (A) 59 BF_F120-AGAC_F120-AGAD 1.20E-03 1.36% BARRIER FAILURE BETWEEN FIRE The component associated with this basic event is evaluated in COMPS F120-AGAC & F120-AGAD Section 7.4.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

60 %F137-A11C-LP 2.09E-04 1.21% FIRE IN ELECTRICAL PENETRATION RM Initiating event - no impact on SAMDA analysis (C)

T-77 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6f (4 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 61 %F157-A19C-LP 2.02E-04 1.16% FIRE IN I & C EQUIP. RM Initiating event - no impact on SAMDA analysis 62 HR-FB-JLP10-01 6.96E-04 1.16% Operator Fails to Feed during JL POS 10 Procedural changes are not in the scope of this SAMDA analysis w/makeup established 63 %F137-A10C-LP 1.81E-04 1.05% FIRE IN 480V CLASS 1E MCC 03C RM Initiating event - no impact on SAMDA analysis 64 %F157-A25C-LP 1.81E-04 1.02% FIRE IN I & C EQUIP. RM Initiating event - no impact on SAMDA analysis 65 HR-FB-CCP06 5.96E-03 1.02% Operator Fails to Feed during CC POS 6 Procedural changes are not in the scope of this SAMDA analysis 66 HR-FB-S2P06 5.96E-03 1.01% Operator Fails to Feed during S2 POS 6 Procedural changes are not in the scope of this SAMDA analysis 67 COMBINATION_20-LPF 9.34E+00 1.00% HEP dependency factor for HR-RS-CCP06, Procedural changes are not in the scope of this SAMDA analysis HR-FB-CCP06 68 HR-RS-CCP06 2.69E-02 1.00% Operator Fails to Restore SCS during CC POS Procedural changes are not in the scope of this SAMDA analysis 6

69 COMBINATION_14-LPF 9.34E+00 0.99% HEP dependency factor for HR-RS-S2P06, Procedural changes are not in the scope of this SAMDA analysis HR-FB-S2P06 70 HR-RS-S2P06 2.69E-02 0.99% Operator Fails to Restore SCS during S2 POS Procedural changes are not in the scope of this SAMDA analysis 6

71 %F120-AGAA-LP 1.71E-04 0.97% FIRE IN GENERAL ACCESS AREA-120' A Initiating event - no impact on SAMDA analysis 72 HR-FB-LPP04B 4.73E-03 0.93% Operator Fails to Feed during LP POS 4B Procedural changes are not in the scope of this SAMDA analysis 73 %F078-AEEB-LP 4.12E-04 0.91% FIRE IN CLASS 1E SWITCHGEAR 01B Initiating event - no impact on SAMDA analysis ROOM 74 COMBINATION_22-LPF 1.15E+01 0.91% HEP dependency factor for HR-RS-LPP04B, Procedural changes are not in the scope of this SAMDA analysis HR-FB-LPP04B 75 HR-RS-LPP04B 3.54E-02 0.91% Operator Fails to Restore SCS during LP POS Procedural changes are not in the scope of this SAMDA analysis 4B 76 COMBINATION_9-LPF 7.28E+01 0.90% HEP dependency factor for HR-MI-JLP10, Procedural changes are not in the scope of this SAMDA analysis HR-FB-JLP10-02 77 HR-FB-JLP10-02 6.96E-04 0.90% Operator Fails to Feed during JL POS 10 Procedural changes are not in the scope of this SAMDA analysis w/makeup failed 78 HR-MI-JLP10 6.14E-03 0.90% Operator Fails to Isolate and Makeup JL at Procedural changes are not in the scope of this SAMDA analysis POS 10 79 %F000-ACVL-LP 9.52E-04 0.88% FIRE IN CVCS ACCESS AREA Initiating event - no impact on SAMDA analysis 80 %F100-A08C-LP 6.06E-04 0.85% FIRE IN N1E DC & IP EQUIPMENT RM Initiating event - no impact on SAMDA analysis 81 %F000-AC-LP 7.78E-03 0.76% FIRE IN ACCESS AREA Initiating event - no impact on SAMDA analysis 82 %F078-A11C-LP 1.48E-04 0.76% FIRE IN ESSENTIAL CHILLER RM Initiating event - no impact on SAMDA analysis T-78 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 6f (5 of 5)

Fussell-Item Event Name Probability Vesely Description Disposition No.

Importance 83 %F050-A04A-LP 1.48E-04 0.75% FIRE IN SC PUMP & MINI FLOW HX RM Initiating event - no impact on SAMDA analysis 84 %F055-A02C-LP 1.48E-04 0.75% FIRE IN CCW PUMP RM Initiating event - no impact on SAMDA analysis 85 %F055-A02A-LP 1.45E-04 0.73% FIRE IN CCW PUMP RM Initiating event - no impact on SAMDA analysis 86 %F000-RW-LP 1.45E-02 0.71% FIRE IN ACCESS AREA Initiating event - no impact on SAMDA analysis 87 BF_F000-ACVU_F000-RW 8.60E-03 0.71% BARRIER FAILURE BETWEEN FIRE The component associated with this basic event is evaluated in COMPS F000-ACVU & F000-RW Section 7.4.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

88 %F100-AEEB-LP 3.21E-04 0.70% FIRE IN 480V CLASS 1E MCC 01B ROOM Initiating event - no impact on SAMDA analysis 89 BE-RATE-P11 9.66E-04 0.69% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS11 duration 90 BE-RATE-P13 2.44E-03 0.69% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS13 duration 91 %F055-AGAA-LP 1.20E-04 0.68% FIRE IN GENERAL ACCESS AREA-55' A Initiating event - no impact on SAMDA analysis 92 %F000-ACV-LP 1.88E-03 0.66% FIRE IN CVCS ACCESS AREA Initiating event - no impact on SAMDA analysis 93 %F157-AMAX-LP 1.09E-04 0.63% FIRE IN MEETING ROOM Initiating event - no impact on SAMDA analysis 94 %F100-A06D-LP 1.80E-04 0.63% FIRE IN GENERAL ACCESS AREA Initiating event - no impact on SAMDA analysis 95 AS-CCDP-LT 1.00E-01 0.56% LONG TERM ALTERNATE SHUTDOWN This event represents operator actions and procedural changes are CCDP EST. (> 1.5 HRS FOR RS OR > 3 HRS not in the scope of this SAMDA analysis FOR SG) 96 BE-RATE-P03B 2.74E-03 0.55% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis POS03B duration 97 %F000-ADGD-LP 4.65E-03 0.55% FIRE IN DIESEL GENERATOR ROOM Initiating event - no impact on SAMDA analysis 98 MSEVO-A-102 5.56E-03 0.51% MS ADV 102 ON SG1 FAILS TO OPEN T-79 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7a (1 of 2)

List of Additional Basic Events from APR1400 PRA Cutset Review (At-Power Internal Events)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 1 PELXKD2- 3.37E-06 0.24% 2/2 CCF OF LOOP CONTROLLER LX09A Given the low importance of this event, very little benefit would be LX09A11B 12/LX11B 12 FAILURE obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

2 MSOPH-S-SGADV 5.57E-03 0.41% Operator Fails to Open MSADV to remove steam Procedural changes are not in the scope of this SAMDA analysis from SGs 3 MSSVWQ4- 7.66E-06 0.41% CCF OF MSSVS ON SG LINES 1A, 1B, 2A AND 1A1B2A2B 2B 4 COMBINATION_65 7.10E+01 0.39% HEP dependency factor for MSOPH-S-SGADV, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 5 MSEVXQ3-011/12/13 1.20E-05 0.34% 2/2 CCF OF 3/4 MSIV 011/012/013 FAIL TO CLOSE 6 MSEVXQ3-011/12/14 1.20E-05 0.34% 2/2 CCF OF 3/4 MSIV 011/012/014 FAIL TO CLOSE 7 MSEVXQ3-011/13/14 1.20E-05 0.34% 2/2 CCF OF 3/4 MSIV 011/013/014 FAIL TO CLOSE 8 MSEVXQ3-012/13/14 1.20E-05 0.34% 2/2 CCF OF 3/4 MSIV 012/013/014 FAIL TO CLOSE 9 MSEVWQ4-101/2/3/4 7.76E-05 0.25% 4/4 CCF OF MS ADVs 101/102/103/104 FAIL TO OPEN 10 SIMPWQ4- 4.14E-06 0.23% 4/4 CCF OF CSP PP01A/PP01B AND SCP CSP1A/B/SCP1A/B PP01A/PP01B FAIL TO START 11 MSEVXQ4- 1.01E-05 0.28% 2/2 CCF OF 4/4 MSIV 011/012/013/014 FAIL TO 011/12/13/14 CLOSE 12 AFPVKQ3- 6.70E-06 0.37% 3/4 CCF OF AFW TDP01A/MDP02A/B FAIL TO The components associated with this basic event are evaluated in TP01A/MP02A/B RUN Sections 7.3.3 through 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

12 AFPVKQ3- 6.70E-06 0.34% 3/4 CCF OF AFW TDP01B/MDP02A/B FAIL TO The components associated with this basic event are evaluated in TP01B/MP02A/B RUN Sections 7.3.3 through 7.3.6. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

13 WMVVT-S-V1700 5.53E-04 0.37% WM MANUAL VALVE 1700 TRANSFER Given the low importance of this event, very little benefit would be CLOSED obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

T-80 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7a (2 of 2)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 14 CVOPV-S-MV509 1.00E-01 0.19% LOCAL MANUAL FTO MV-509 FOR IRWST Procedural changes are not in the scope of this SAMDA analysis REFILL AFTER SIGNAL FAILURE 15 SIMVWQ4- 2.73E-06 0.23% 4/4 CCF OF DVI LINE MOV 616/626/636/646 Given the low importance of this event, very little benefit would be 616/26/36/46 FAIL TO OPEN obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

16 CVOPH-S-IRWST 9.94E-04 0.29% OPERATOR FAILS TO REFILL THE IRWST Procedural changes are not in the scope of this SAMDA analysis VIA CVCS 17 HR-RCSCD1-ISOL 3.72E-04 0.36% Operator Fails to Take Action for SG Cooldown, Procedural changes are not in the scope of this SAMDA analysis RC Depressurization and SG Isolation 18 SIOPH-S-LTC-SC 5.36E-05 0.14% Operator Fails to Align SCS For Long Term Procedural changes are not in the scope of this SAMDA analysis Cooling 19 HR-RCSCD2 1.30E-03 0.23% Operator Fails to Take Action for SG Cooldown, Procedural changes are not in the scope of this SAMDA analysis RC Depressurization 20 COMBINATION_203 5.04E+04 0.14% HEP dependency factor for HR-RCSCD1-ISOL, Procedural changes are not in the scope of this SAMDA analysis 2 SIOPH-S-LTC-SC, CVOPH-S-IRWST 21 COMBINATION_203 2.08E+03 0.14% HEP dependency factor for HR-RCSCD1-ISOL, Procedural changes are not in the scope of this SAMDA analysis 1 HR-RCSCD2, CVOPH-S-IRWST 22 CCMVO-A-097 9.63E-04 0.40% CCW MOV V097 FAILS TO OPEN Given the low importance of this event, very little benefit would be obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

23 CCMVO-B-098 9.63E-04 0.40% CCW MOV V098 FAILS TO OPEN Given the low importance of this event, very little benefit would be obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

24 CSMVO1B-004 9.63E-04 0.40% CS ISOL. MOV 004 IN CS TR. B HX DISCH. Given the low importance of this event, very little benefit would be PATH FAILS TO OPEN obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

T-81 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7b (1 of 1)

List of Additional Basic Events from APR1400 PRA Cutset Review (At-Power Internal Flooding Events)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 1 MSOPH-S-SGADV 5.57E-03 0.15% Operator Fails to Open MSADV to remove steam Procedural changes are not in the scope of this SAMDA analysis from SGs 2 MSSVWQ4- 7.66E-06 0.15% CCF OF MSSVS ON SG LINES 1A, 1B, 2A AND 1A1B2A2B 2B 3 COMBINATION_65 7.10E+01 0.15% HEP dependency factor for MSOPH-S-SGADV, Procedural changes are not in the scope of this SAMDA analysis RCOPH-S-SDSE-FW 4 DCBCM-M-BC01M 2.00E-03 0.15% NON-CLASS 1E 125V DC BATT. CHARGER Given the low importance of this event, very little benefit would be BC01M UNAVAILABLE DUE TO T&M obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

5 DCOPH-S-NSBC- 5.00E-01 0.16% OPERATOR FAILS TO TRANSFER SOURCE Procedural changes are not in the scope of this SAMDA analysis ALIGN FROM BC01M/N TO BC05N 6 COMBINATION_56 6.35E+04 0.13% HEP dependency factor for DCOPH-S-NSBC- Procedural changes are not in the scope of this SAMDA analysis ALIGN, FPOPH-2-ISO-FL, AFOPH-S-ALT-LT, RCOPH-S-SDSL 7 %IE-120-11B-FP-X 1.70E-05 0.81% MAJ BRK (>1180 GPM) OF FP PIPING IN B Initiating event - no impact on SAMDA analysis QUAD 120 FT EL RM 120-A11B OR 120-A13B T-82 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7c (1 of 2)

List of Additional Basic Events from APR1400 PRA Cutset Review (At-Power Internal Fire Events)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 1 DGSQA-B-LOADSQ 3.33E-03 0.56% LOAD SEQUNCER B FAILS TO OPERATE The component associated with this basic event is evaluated in Section 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

2 %F000-C01-156-1 7.40E-05 0.40% FIRE IN F000-C01 - CONTAINMENT - Initiating event - no impact on SAMDA analysis UNSUPPRESSED TRANS FIRES EL 156'-0" AREA 1 3 %F000-C01-100-1 6.73E-05 0.36% FIRE IN F000-C01 - CONTAINMENT - Initiating event - no impact on SAMDA analysis UNSUPPRESSED TRANS FIRES EL 100'-0" AREA 1 4 %F000-C01-114-1 6.73E-05 0.36% FIRE IN F000-C01 - CONTAINMENT - Initiating event - no impact on SAMDA analysis UNSUPPRESSED TRANS FIRES EL 114'-0" AREA 1 5 %F000-C01-136-1 6.73E-05 0.36% FIRE IN F000-C01 - CONTAINMENT - Initiating event - no impact on SAMDA analysis UNSUPPRESSED TRANS FIRES EL 136'-6" AREA 1 6 %F137-A02D 3.64E-04 0.49% FIRE IN F137-A02D - ELECTRICAL EQUIP. RM Initiating event - no impact on SAMDA analysis 7 BF_F137-A02D_F157- 1.20E-03 0.20% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section AMCR F137-A02D & F157-AMCR 7.4.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

8 %F000-AFHU 3.42E-04 0.32% FIRE IN F000-AFHU - FUEL HANDLING Initiating event - no impact on SAMDA analysis UPPER AREA 9 %F120-A05D-U 3.01E-04 0.27% FIRE IN F120-A05D - ELECTRICAL Initiating event - no impact on SAMDA analysis EQUIPMENT RM D - UNSUPPRESSED 10 VDHVZO8- 9.96E-06 0.38% 8/8 CCF OF EDG ROOM CUBICLE COOLER The components associated with this basic event are evaluated in HV12/13ABCD HV12A/12B/12C/12D 13A/13B/13C/14D FAIL Sections 7.15.11 through 7.15.18. A design change would be expected TO RUN FOR 1HR to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

11 DGSQWQ4- 9.89E-06 0.38% 4/4 CCF OF LOAD SEQUNCER A/B/C/D FAIL The component associated with this basic event is evaluated in Section LOADSQABCD TO OPERATE 7.1.5. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

12 WMVVT-S-V1700 5.53E-04 0.29% WM MANUAL VALVE 1700 TRANSFER Given the low importance of this event, very little benefit would be CLOSED obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

13 SIMVT-B-303 3.71E-05 0.47% SI PUMP PP02B/D MINI. FLOW LINE MOV Given the low importance of this event, very little benefit would be V303 FAILS TO REMAIN OPEN obtained from efforts to reduce the importance further. Therefore, no SAMA items are added T-83 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7c (2 of 2)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 14 %F100-A05C 2.06E-04 0.28% FIRE IN F100-A05C - ELECTRICAL Initiating event - no impact on SAMDA analysis EQUIPMENT RM C 15 SXCTWQ4- 6.89E-06 0.26% 4/4 CCF OF SXCT 1A, 2A, 1B AND 2B TO CT01A/02A/01B/02B START 16 %F100-A05D-U 1.91E-04 0.24% FIRE IN F100-A05D - ELECTRICAL Initiating event - no impact on SAMDA analysis EQUIPMENT RM D - UNSUPPRESSED 17 %F120-A08D 1.87E-04 0.15% FIRE IN F120-A08D - 480V N1E MCC RM Initiating event - no impact on SAMDA analysis 18 %F137-ASTD 2.37E-05 0.09% FIRE IN F137-ASTD - STAIR Initiating event - no impact on SAMDA analysis 19 BF_F137- 8.60E-03 0.09% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section ASTD_F157-AMCR F137-ASTD & F157-AMCR 7.4.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

20 %F078-AGAD-U 5.05E-05 0.35% FIRE IN F078-AGAD - GENERAL ACCESS Initiating event - no impact on SAMDA analysis AREA-78' D - UNSUPPRESSED 21 BF_F137-A05D_F157- 1.20E-03 0.08% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section AMCR F137-A05D & F157-AMCR 7.4.3. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

22 %F120-A08C 1.44E-04 0.18% FIRE IN F120-A08C - 480V N1E MCC RM Initiating event - no impact on SAMDA analysis 23 CCMPWQ4- 4.76E-06 0.18% 4/4 CCF OF CCW PUMPS PP01A/1B/2A/2B The components associated with this basic event are evaluated in PP01A/2A/1B/2B FAIL TO START Sections 7.5.1 and 7.5.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 24 WOMPWQ4- 4.76E-06 0.18% 4/4 CCF OF ECW PUMPS 1A/2A/1B/2B FAIL The components associated with this basic event are evaluated in PP01A/2A/1B/2B TO START Sections 7.18.1 and 7.18.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit 25 %F100-AEEA 3.14E-04 0.40% FIRE IN F100-AEEA - 480V CLASS 1E MCC Initiating event - no impact on SAMDA analysis 01A RM T-84 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7d (1 of 4)

List of Additional Basic Events from APR1400 PRA Cutset Review (LPSD Internal Events)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance HR-FB-JLP05-02 2.72E-03 0.43% Operator Fails to Feed during JL POS 5 w/makeup Procedural changes are not in the scope of this SAMDA analysis 1

failed 2 HR-MI-JLP05 7.18E-04 0.43% Operator Fails to Isolate and Makeup JL at POS 5 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_20- 1.93E+01 0.43% HEP dependency factor for HR-MI-JLP05, HR-FB- Procedural changes are not in the scope of this SAMDA analysis 3

LP JLP05-02 4 HR-FB-KVP05 3.49E-04 0.35% Operator Fails to Feed during KV POS 5 Procedural changes are not in the scope of this SAMDA analysis 5 HR-RS-KVP05 4.18E-01 0.36% Operator Fails to Restore SCS during KV POS 5 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_52- 1.00E+00 0.35% HEP dependency factor for HR-RS-KVP05, HR- Procedural changes are not in the scope of this SAMDA analysis 6

LP FB-KVP05 HR-FB-JLP11-02 5.37E-04 0.32% Operator Fails to Feed during JL POS 11 Procedural changes are not in the scope of this SAMDA analysis 7

w/makeup failed 8 HR-MI-JLP11 7.18E-04 0.32% Operator Fails to Isolate and Makeup JL at POS 11 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_24- 9.41E+01 0.32% HEP dependency factor for HR-MI-JLP11, HR-FB- Procedural changes are not in the scope of this SAMDA analysis 9

LP JLP11-02 HR-FB-JLP06-02 2.72E-03 0.34% Operator Fails to Feed during JL POS 6 w/makeup Procedural changes are not in the scope of this SAMDA analysis 10 failed 11 HR-MI-JLP06 7.18E-04 0.34% Operator Fails to Isolate and Makeup JL at POS 6 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_27- 1.93E+01 0.34% HEP dependency factor for HR-MI-JLP06, HR-FB- Procedural changes are not in the scope of this SAMDA analysis 12 LP JLP06-02 13 HR-FB-S1P12A 3.49E-04 0.27% Operator Fails to Feed during S1 POS 12A Procedural changes are not in the scope of this SAMDA analysis 14 HR-RS-S1P12A 3.23E-01 0.28% Operator Fails to Restore SCS during S1 POS 12A Procedural changes are not in the scope of this SAMDA analysis COMBINATION_53- 1.00E+00 0.27% HEP dependency factor for HR-RS-S1P12A, HR- Procedural changes are not in the scope of this SAMDA analysis 15 LP FB-S1P12A 16 HR-FB-S2P05 3.49E-04 0.22% Operator Fails to Feed during S2 POS 5 Procedural changes are not in the scope of this SAMDA analysis 17 HR-RS-S2P05 4.18E-01 0.23% Operator Fails to Restore SCS during S2 POS 5 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_62- 1.00E+00 0.22% HEP dependency factor for HR-RS-S2P05, HR- Procedural changes are not in the scope of this SAMDA analysis 18 LP FB-S2P05 HR-FB-SOP11-01 3.49E-04 0.06% Operator Fails to Feed during SL POS 11 Procedural changes are not in the scope of this SAMDA analysis 19 w/makeup established 20 HR-RS-SOP11 5.76E-03 0.22% Operator Fails to Restore SCS during SO POS 11 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_3- 1.00E+00 0.22% HEP dependency factor for HR-RS-SOP11, HR- Procedural changes are not in the scope of this SAMDA analysis 21 LP FB-SOP11-01 22 HR-FB-ESP05 3.49E-04 0.19% Operator Fails to Feed during ES POS 5 Procedural changes are not in the scope of this SAMDA analysis T-85 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7d (2 of 4)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 23 HR-RS-ESP05 4.18E-01 0.19% Operator Fails to Restore SCS during ES POS 5 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_63- 1.00E+00 0.19% HEP dependency factor for HR-RS-ESP05, HR- Procedural changes are not in the scope of this SAMDA analysis 24 LP FB-ESP05 PFHBWQ4- 2.73E-05 0.43% 4/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW2OUAT SW01A/1B/1C/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to 25 cost more than the total maximum cost reduction and, as a result, not provide a positive benefit VKOPH-S-ECCS 1.00E-01 0.18% OPERATOR FAILS TO ACTUATE ECCS Procedural changes are not in the scope of this SAMDA analysis 26 EXHAUST FAN AH01A/B SXCTKQ4- 1.10E-06 0.16% 4/4 CCF OF SXCT 1A, 2A, 1B AND 2B TO RUN 27 CT01A/02A/01B/02B SIMPZQ4- 1.06E-06 0.14% 4/4 CCF OF CSP PP01A, PP01B AND SCP The components associated with this basic event are evaluated in CSP1A/B/SCP1A/B PP01A, PP01B TO RUN FOR 1HR Sections 7.6.1, 7.6.2, 7.24.1, and 7.24.2. A design change would be 28 expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit PPSO-OS-PPS 1.20E-06 0.41% CCF OF PPS OPERATING SYSTEM The component associated with this basic event is evaluated in Section 29 SOFTWARE 7.21.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

SIMPKQ4- 9.21E-07 0.13% 4/4 CCF OF CSP PP01A/PP01B AND SCP PP01A The components associated with this basic event are evaluated in CSP1A/B/SCP1A/B /PP01B FAIL TO RUN Sections 7.6.1, 7.6.2, 7.24.1, and 7.24.2. A design change would be 30 expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit HR-FB-S1P03B-01 3.55E-04 0.11% Operator Fails to F&B during S1 POS 3B (LTOP Procedural changes are not in the scope of this SAMDA analysis 31 re-closed) 32 HR-RS-S1P03B 2.88E-01 0.19% Operator Fails to Restore SCS during S1 POS 3B Procedural changes are not in the scope of this SAMDA analysis HR-SG-S1P03B 6.06E-04 0.11% Operator Fails to Remove Steam during S1 at POS Procedural changes are not in the scope of this SAMDA analysis 33 3A COMBINATION_10- 8.34E+01 0.11% HEP dependency factor for HR-RS-S1P03B, HR- Procedural changes are not in the scope of this SAMDA analysis 34 LP SG-S1P03B,HR-FB-S1P03B-01 PFHBC1B-SW01B-A2 6.66E-03 0.36% PCB SW01B-A2 OF 4.16KV SWGR SW01B The component associated with this basic event is evaluated in Section 35 FAILS TO CLOSE 7.11.4. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

SIMPR1B-SCPP01B 2.83E-03 0.28% FAILS TO RUN SC PUMP 2 PP01B The component associated with this basic event is evaluated in Section 36 7.24.2. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

SIMPR1A-SCPP01A 2.83E-03 0.21% FAILS TO RUN SC PUMP PP01A The component associated with this basic event is evaluated in Section 37 7.24.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

HR-FB-JLP04B-02 5.37E-04 0.12% Operator Fails to Feed during JL POS 4B Procedural changes are not in the scope of this SAMDA analysis 38 w/makeup failed T-86 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7d (3 of 4)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 39 HR-MI-JLP04B 7.18E-04 0.12% Operator Fails to Isolate and Makeup JL at POS 4B Procedural changes are not in the scope of this SAMDA analysis COMBINATION_49- 9.41E+01 0.12% HEP dependency factor for HR-MI-JLP04B, HR- Procedural changes are not in the scope of this SAMDA analysis 40 LP FB-JLP04B-02 PFHBWQ3- 1.65E-05 0.22% 3/4 CCF OF PCB BETWEEN UAT & 4.16KV The components associated with this basic event are evaluated in SW2OUATABD SW01A/1B/1D FAIL TO OPEN Sections 7.11.6 through 7.11.9. A design change would be expected to 41 cost more than the total maximum cost reduction and, as a result, not provide a positive benefit VGAHKQ4- 6.06E-07 0.09% 4/4 CCF OF ESW PUMP ROOM FAN Given the low importance of this event, very little benefit would be 42 AH01A/1B/2A/2B AH01A/B/02A/B FAIL TO RUN obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

VKHVKQ4- 6.06E-07 0.09% 4/4 CCF OF RUN FOR CCW PUMP ROOM Given the low importance of this event, very little benefit would be 43 HV13A/13B/14A/14B CUBICLE COOLER HV13A/13B/14A/14B FAIL obtained from efforts to reduce the importance further. Therefore, no TO RUN SAMA items are added.

VOHVKQ4- 6.06E-07 0.09% 4/4 CCF OF RUN FOR CUBICLE COOLER Given the low importance of this event, very little benefit would be 44 HV32A/32B/31A/31B HV32A/32B/31A/31B FAIL TO RUN obtained from efforts to reduce the importance further. Therefore, no SAMA items are added.

%TLOCCW 2.34E-04 0.16% TOTAL LOSS OF COMPONANT COOLING Initiating event - no impact on SAMDA analysis 45 WATER BE-RATE-P14 3.12E-03 0.27% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis 46 POS14 duration PFLOOP-NO-SI 2.00E-03 0.31% CONDITIONAL LOOP AFTER INITIATORS Conditional LOOP event - no impact on SAMDA analysis 47 WHICH DO NOT INITIATE AN SI SIGNAL

%TLOESW 2.34E-04 0.16% TOTAL LOSS OF ESSENTIAL SERVICE Initiating event - no impact on SAMDA analysis 48 WATER VDHVL-B-HV12B 2.28E-03 0.46% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in Section COOLER HV12B FOR 1HR 7.15.12. A design change would be expected to cost more than the 49 total maximum cost reduction and, as a result, not provide a positive benefit.

VDHVL-B-HV13B 2.28E-03 0.46% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in Section COOLER HV13B FOR 1HR 7.15.16. A design change would be expected to cost more than the 50 total maximum cost reduction and, as a result, not provide a positive benefit.

VDHVL-A-HV12A 2.28E-03 0.46% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in Section COOLER HV12A FOR 1HR 7.15.11. A design change would be expected to cost more than the 51 total maximum cost reduction and, as a result, not provide a positive benefit.

VDHVL-A-HV13A 2.28E-03 0.46% FAILS TO RUN EDG ROOM CUBICLE The component associated with this basic event is evaluated in Section COOLER HV13A FOR 1HR 7.15.15. A design change would be expected to cost more than the 52 total maximum cost reduction and, as a result, not provide a positive benefit.

53 HR-FB-KVP12A 3.49E-04 0.07% Operator Fails to Feed during KV POS 12A Procedural changes are not in the scope of this SAMDA analysis T-87 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7d (4 of 4)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 54 HR-RS-KVP12A 3.23E-01 0.07% Operator Fails to Restore SCS during KV POS 12A Procedural changes are not in the scope of this SAMDA analysis COMBINATION_75- 1.00E+00 0.07% HEP dependency factor for HR-RS-KVP12A, HR- Procedural changes are not in the scope of this SAMDA analysis 55 LP FB-KVP12A 56 %CC 6.75E-03 0.28% Loss of Component Cooling Water Initiating event - no impact on SAMDA analysis 57 HR-FB-CCP05 3.49E-04 0.07% Operator Fails to Feed during CC POS 5 Procedural changes are not in the scope of this SAMDA analysis 58 HR-RS-CCP05 4.18E-01 0.07% Operator Fails to Restore SCS during CC POS 5 Procedural changes are not in the scope of this SAMDA analysis COMBINATION_87- 1.00E+00 0.07% HEP dependency factor for HR-RS-CCP05, HR- Procedural changes are not in the scope of this SAMDA analysis 59 LP FB-CCP05 DGDGKQ2-DG01AB 5.55E-05 0.25% 2/4 CCF OF EDG 01A/01B FAIL TO RUN The components associated with this basic event are evaluated in Sections 7.1.1 and 7.1.2. A design change would be expected to cost 60 more than the total maximum cost reduction and, as a result, not provide a positive benefit.

RCPVWQ4-200/1/2/3 2.10E-04 0.18% 4/4 CCF OF RC PV V200/201/202/203 FAIL TO The components associated with this basic event are evaluated in OPEN Sections 7.12.1 through 7.12.4. A design change would be expected to 61 cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

COMBINATION_120- 8.34E+01 0.07% HEP dependency factor for HR-RS-S1P03B, HR- Procedural changes are not in the scope of this SAMDA analysis 62 LP SG-S1P03B SXMPKQ4- 4.63E-07 0.07% 4/4 CCF OF ESW PUMPS PP01A/2A/PP01B/2B The components associated with this basic event are evaluated in PP01A/B/2A/B FAIL TO RUN Sections 7.17.1 and 7.17.2. A design change would be expected to 63 cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

BE-RATE-P02 2.40E-03 0.21% Conversion factor (SD-yr -> Calendar yr) for Quantification factor - no impact on SAMDA analysis 64 POS02 duration T-88 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7e (1 of 1)

List of Additional Basic Events from APR1400 PRA Cutset Review (LPSD Internal Flooding Events)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 1 HR-FB-S2P04B 3.49E-04 0.24% Operator Fails to Feed during S2 POS 4B Procedural changes are not in the scope of this SAMDA analysis 2 HR-RS-S2P06 2.04E-03 0.23% Operator Fails to Restore SCS during S2 POS 6 Procedural changes are not in the scope of this SAMDA analysis 3 %IE-137-29B-FP-X- 1.22E-05 0.27% MAJ BRK (> 2500 GPM) OF FP PIPING IN B Initiating event - no impact on SAMDA analysis LP QUAD 137 FT EL RM 137-A29B (LPSD)

T-89 Rev. 2

APR1400 Applicants Environmental Report - Standard Design Certification Table 7f (1 of 1)

List of Additional Basic Events from APR1400 PRA Cutset Review (LPSD Internal Fire Events)

Item Fussell-Vesely Event Name Probability Description Disposition No. Importance 1 BF_F000-AC_F120- 8.60E-03 0.38% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section AGAA F000-AC & F120-AGAA 7.4.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

2 BF_F000-AC_F137- 8.60E-03 0.39% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section A20A F000-AC & F137-A20A 7.4.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

3 %F157-ATOC-LP 5.54E-05 0.31% FIRE IN TSC EQUIP. REPAIR & MAINT ROOM Initiating event - no impact on SAMDA analysis 4 %F157-A16C-LP 5.52E-05 0.32% FIRE IN GENERAL ACCESS AREA Initiating event - no impact on SAMDA analysis 5 %F120-A15B-LP 1.85E-04 0.40% FIRE IN 480V CLASS 1E MCC 03B RM Initiating event - no impact on SAMDA analysis 6 %F157-A01D-LP 1.82E-04 0.40% FIRE IN I & C EQUIP. RM Initiating event - no impact on SAMDA analysis 7 BF_F000- 8.60E-03 0.21% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section ADGC_F078-A01C F000-ADGC & F078-A01C 7.4.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

8 BF_F000- 8.60E-03 0.21% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section ADGC_F078-A02C F000-ADGC & F078-A02C 7.4.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

9 HR-FB-CCP04B 2.01E-03 0.46% Operator Fails to Feed during CC POS 4B Procedural changes are not in the scope of this SAMDA analysis 10 HR-RS-CCP04B 3.54E-02 0.46% Operator Fails to Restore SCS during CC POS 4B Procedural changes are not in the scope of this SAMDA analysis 11 COMBINATION_44- 2.58E+01 0.46% HEP dependency factor for HR-RS-CCP04B, HR- Procedural changes are not in the scope of this SAMDA analysis LPF FB-CCP04B 12 %F120-A14A-LP 3.65E-05 0.21% FIRE IN SG BLOWDOWN REGEN HX RM Initiating event - no impact on SAMDA analysis 13 %F050-A04B-LP 1.48E-04 0.32% FIRE IN SC PUMP & MINI FLOW HX RM Initiating event - no impact on SAMDA analysis 14 %F122-T01-LP 1.33E-03 0.48% FIRE IN SWITCHGEAR RM Initiating event - no impact on SAMDA analysis 15 BF_F000- 2.40E-03 0.30% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section ADGD_F100-A06D F000-ADGD & F100-A06D 7.4.1. A design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

16 %FY-SAT1-LP 1.29E-03 0.33% FIRE IN STAND-BY AUX. TRANSFORMER 1 Initiating event - no impact on SAMDA analysis AREA 17 MSEVO-A-102 5.56E-03 0.51% MS ADV 102 ON SG1 FAILS TO OPEN 18 MSOPH-S-SGADV- 1.00E+00 0.39% OPERATOR FAILS TO OPEN ADVS USING Procedural changes are not in the scope of this SAMDA analysis HW HAND WHEEL 19 %F137-ANEC-LP 3.43E-03 0.46% FIRE IN ELECTRICAL EQUIPMENT Initiating event - no impact on SAMDA analysis ROOM/CEDM M/G SET RM 20 BF_F137-A01C_F137- 9.00E-03 0.26% BARRIER FAILURE BETWEEN FIRE COMPS The component associated with this basic event is evaluated in Section ANEC F137-A01C & F137-ANEC 7.4.1. design change would be expected to cost more than the total maximum cost reduction and, as a result, not provide a positive benefit.

21 %F157-ACPX-LP 1.28E-04 0.30% FIRE IN COMPUTER RM PACU RM Initiating event - no impact on SAMDA analysis 22 %F120-A11B-LP 1.23E-04 0.27% FIRE IN GENERAL ACCESS AREA-120' B Initiating event - no impact on SAMDA analysis T-90 Rev. 2

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