CHAPTER 19—PRA AND SEVERE ACCIDENT LIST OF FIGURES

U.S. EPR FINAL SAFETY ANALYSIS REPORT
CHAPTER 19—PRA AND SEVERE
ACCIDENT
LIST OF FIGURES
Figure 19.1-1—Cooling Water Dependencies Modeled in the U.S. EPR PRA... 19.1-514
Figure 19.1-2—Ventilation Dependencies Modeled in the U.S. EPR PRA......... 19.1-515
Figure 19.1-3—Selected Dependencies on Electric Power Modeled in the
U.S. EPR PRA ........................................................................... 19.1-516
Figure 19.1-4—U.S. EPR Initiating Events Contributions - Level 1 Internal
Event.......................................................................................... 19.1-517
Figure 19.1-5—U.S. EPR Level 1 Internal Events Uncertainty Analysis
Results - Cumulative Distributions for Internal Events CDF ...... 19.1-518
Figure 19.1-6—Natural Circulation Flowpaths in the Primary System................ 19.1-519
Figure 19.1-7—Decomposition Event Tree for Long Term Challenges .............. 19.1-520
Figure 19.1-8—Composite Containment Fragility Curve at 395°F ..................... 19.1-521
Figure 19.1-9—U.S. EPR Level 2 Internal Events Uncertainty Analysis
Results - Cumulative Distribution for Internal Events LRF......... 19.1-522
Figure 19.1-10—Event Tree for Seismic Loss of Offsite Power (S LOOP)......... 19.1-523
Figure 19.1-11—Event Tree for Seismic Small LOCA (S SLOCA)..................... 19.1-524
Figure 19.1-12—U.S. EPR Initiating Event Contributions - Level 1 Flooding ..... 19.1-525
Figure 19.1-13—U.S. EPR Level 1 Internal Flood Events Uncertainty
Analysis Results - Cumulative Distribution for Flood Events
CDF.......................................................................................... 19.1-526
Figure 19.1-14—U.S. EPR Level 2 Flood Events Uncertainty Analysis
Results - Cumulative Distribution for Flood Events LRF .......... 19.1-527
Figure 19.1-15—U.S. EPR Initiating Event Contributions - Level 1 Fire............. 19.1-528
Figure 19.1-16—Cross-section of Safeguard Building 4 Illustrating the
PRA Fire Areas........................................................................ 19.1-529
Figure 19.1-17—Cross-section of Safeguard Building 2 Illustrating the
PRA Fire Areas ........................................................................ 19.1-530
Figure 19.1-18—U.S. EPR Level 1 Internal Fire Events Uncertainty Analysis
Results - Cumulative Distribution for Fire Events CDF ............ 19.1-531
Figure 19.1-19—U.S. EPR Level 2 Fire Events Uncertainty Analysis Results Cumulative Distribution Function for Fire Events LRF ............. 19.1-532
Figure 19.1-20—Time to TAF - Level 1 Shutdown ............................................. 19.1-533
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Figure 19.1-21—U.S. EPR Initiating Event Contributions - Level 1 Shutdown ... 19.1-534
Figure 19.1-22—U.S. EPR Shutdown State Contribution - Level 1 Shutdown ... 19.1-535
Figure 19.1-23—U.S. EPR Level 1 Shutdown Events Uncertainty Analysis
Results Cumulative Distribution for Low Power and
Shutdown CDF ........................................................................ 19.1-536
Figure 19.1-24—U.S. EPR Level 1 Initiating Event Contributions to Total
CDF at Power........................................................................... 19.1-537
Figure 19.1-25—U.S. EPR POS Contributions to Total CDF ............................. 19.1-538
Figure 19.1-26—U.S. EPR Level 2 Initiating Event Contribution to Total
At-Power LRF........................................................................... 19.1-539
Figure 19.1-27—U.S. EPR Level 2 Release Category Contribution to Total
At-Power LRF .......................................................................... 19.1-540
Figure 19.1-28—U.S. EPR System Ranked by Importance (FV) - Level 1
Total......................................................................................... 19.1-541
Figure 19.1-29— U.S. EPR Level 1 Internal Events Total Uncertainty
Analysis Results Cumulative Distribution for All Internal,
Fire and Flood Events CDF .................................................... 19.1-542
Figure 19.1-30—U.S. EPR Level 2 Internal Events Total Uncertainty Analysis
Results Cumulative Distribution for All Internal, Fire and
Flood Events LRF .................................................................... 19.1-543
Figure 19.1-31—Comparison of SME and RLE for Hard and Soft Soil Sites ..... 19.1-544
Figure 19.1-32—POS CA Release Category Contributions to Shutdown LRF... 19.1-545
Figure 19.1-33—POS CB Release Category Contributions to Shutdown LRF... 19.1-546
Figure 19.1-34—POS D Release Category Contributions to Shutdown LRF ..... 19.1-547
Figure 19.1-35—POS E Release Category Contributions to Shutdown LRF ..... 19.1-548
Figure 19.1-36—POS Contributions to Shutdown LRF ...................................... 19.1-549
Figure 19.1-37—Initiating Events Contributions to Shutdown LRF..................... 19.1-550
Figure 19.1-38—POS Contributions to Total LRF .............................................. 19.1-551
Figure 19.2-1—Core Melt Stabilization System .................................................... 19.2-72
Figure 19.2-2—Severe Accident Heat Removal System ...................................... 19.2-73
Figure 19.2-3—Molten Debris Spreading Area..................................................... 19.2-74
Figure 19.2-4—Tolerance Limit Plot of Hydrogen Production .............................. 19.2-75
Figure 19.2-5—Hydrogen Concentrations through the U.S. EPR Containment ... 19.2-76
Figure 19.2-6—Tolerance Limit Plot of Hydrogen Concentration ......................... 19.2-77
Figure 19.2-7—Tolerance Limit Plot of Containment AICC Pressure................... 19.2-78
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Figure 19.2-8—Tolerance Limit Plot of Sigma Index for the Pump/SG
Compartment ............................................................................... 19.2-79
Figure 19.2-9—Hydrogen Concentration at Significant Events ............................ 19.2-80
Figure 19.2-10—Time of RPV Rupture versus Duration of Retention Period....... 19.2-81
Figure 19.2-11—Temperature Profiles within the Gate after Contact with
an Oxidic Melt ............................................................................ 19.2-82
Figure 19.2-12—Temperature Profiles within the Gate after Contact with
a Metallic Melt............................................................................ 19.2-83
Figure 19.2-13—Corium Height as a Function of Distance from Melt Channel,
100% Gate Failure ..................................................................... 19.2-84
Figure 19.2-14—Corium Height as a Function of Distance from Melt Channel,
10% Gate Failure ....................................................................... 19.2-85
Figure 19.2-15—Containment Pressure following Gate Failure ........................... 19.2-86
Figure 19.2-16—Variation of Power Into Cooling Channels (kW/ft²) .................... 19.2-87
Figure 19.2-17—Temperature Profiles within the Cooling Plate (<6 hours) ......... 19.2-88
Figure 19.2-18—Temperature Profiles within the Cooling Plate (>6 hours,
<30 days) ................................................................................... 19.2-89
Figure 19.2-19—RCS Pressure at RPV Failure.................................................... 19.2-90
Figure 19.2-20—Bounding In-Core Temperature and Pressure Development
during a Severe Accident........................................................... 19.2-91
Figure 19.2-21—Course of Primary Events during a Severe Accident................. 19.2-92
Figure 19A-1—Loss of Divisional Emergency AC Power ...................................... 19A-39
Figure 19A-2—Failure to Scram Following Transient ............................................ 19A-40
Figure 19A-3—General Transient.......................................................................... 19A-41
Figure 19A-4—Induced Steam Generator Tube Rupture ...................................... 19A-42
Figure 19A-5—ISLOCA Due to RCP Thermal Barrier Tube Break........................ 19A-43
Figure 19A-6—ISLOCA Due to Tube Rupture in CVCS High Pressure Cooler..... 19A-44
Figure 19A-7—ISLOCA Due to Rupture of High Pressure CVCS Pipe Outside
Containment .................................................................................. 19A-45
Figure 19A-8—ISLOCA Due to Spurious Opening of Reducing Station................ 19A-46
Figure 19A-9—ISLOCA Due to Break in LHSI Cold Leg Injection Valves
with LHSI Rupture in Respective SAB ..........................................19A-47
Figure 19A-10—ISLOCA Due to Break in MHSI Cold Leg Injection Valves
with MHSI Rupture in Respective SAB........................................ 19A-48
Figure 19A-11—ISLOCA Due to Failure of Suction Line MOVs and
Subsequent RHR Line Rupture in Respective SAB..................... 19A-49
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Figure 19A-12—Loss of Balance of Plant Closed Loop Cooling Water or
Auxiliary Cooling Water................................................................ 19A-50
Figure 19A-13—Large Loss-of-Coolant Accident .................................................. 19A-51
Figure 19A-14—Loss of Main Condenser.............................................................. 19A-52
Figure 19A-15—Loss of Component Cooling Water or Emergency Service
Water ...........................................................................................19A-53
Figure 19A-16—Loss of Main Feedwater .............................................................. 19A-54
Figure 19A-17—Loss of Offsite Power .................................................................. 19A-55
Figure 19A-18—Medium Loss-of-Coolant Accident............................................... 19A-56
Figure 19A-19—Spurious Opening of Main Steam Safety Valve .......................... 19A-57
Figure 19A-20—Steam Generator Tube Rupture .................................................. 19A-58
Figure 19A-21—Steam-Line Break Inside Containment........................................ 19A-59
Figure 19A-22—Steam Line Break Outside Containment ..................................... 19A-60
Figure 19A-23—Small Loss-of-Coolant Accident .................................................. 19A-61
Figure 19B-1—LOCA During Shutdown State C ................................................... 19B-11
Figure 19B-2—LOCA During Shutdown State D or E............................................ 19B-12
Figure 19B-3—Loss of RHR During State C.......................................................... 19B-13
Figure 19B-4—Loss of RHR During State D.......................................................... 19B-14
Figure 19B-5—Uncontrolled Level Drop During Shutdown State C ...................... 19B-15
Figure 19B-6—Uncontrolled Level Drop During Shutdown State D ...................... 19B-16
Figure 19C-1—Containment Event Tree for CDES with Guaranteed
Containment Failure......................................................................19C-17
Figure 19C-2—Containment Event Tree for IS LOCA CDES ................................19C-18
Figure 19C-3—Containment Event Tree for CDES Link Event Tree
Sequences Resulting in Limited Core Damage ............................19C-19
Figure 19C-4—Containment Event Tree for Low Pressure CDES or
CDES which depressurizes in Stage 1 High Pressure CET .........19C-20
Figure 19C-5—Containment Event Tree for Unscrubbed SGTR Sequences........19C-21
Figure 19C-6—Containment Event Tree for Scrubbed SGTR Sequences............19C-22
Figure 19C-7—First Stage Containment Event Tree for High Pressure CDES .....19C-23
Figure 19C-8—Second Stage Containment Event Tree for CDES Remaining
at High Pressure ...........................................................................19C-24
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