ML18337A398

C-SGTR RASP Handbook Vol 5 Worksheet CDF Sequences to Estimate LERF Public v3

ML18337A398
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Issue date:	12/04/2018
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This excel file is to provide the CDF sequences and calculation summary for the SPAR model example that was used to estimate LERF from C-SGTR sequences as documented in Appendix 2-D of the RASP Handbook Volume 5.

Table D-2 Summary Table 07/27/2017 Total CDF In 38 CDF in Residue subject to CDF LERF Category p(csgtr) seqs. (seqs.39-711) csgtr (csgtr) (csgtr) challenge Plant CDF = 2.95E-05 1.15E-06 3.07E-05 96.26%

1 HDL no RCS loop clearing 4.90E-06 1.90E-07 5.09E-06 0.024 1.2E-07 1.2E-07 2 HDL with RCS loop clearing 2.09E-07 8.13E-09 1.00E-08 1 1.0E-08 1.0E-08 Non HDL CDF with 3 0.05 3.3E-08 3.3E-08 subsumed FSG ATWS with failure of 4 3.79E-07 1.47E-08 3.94E-07 0.05 2.0E-08 2.0E-08 pressure relief 5 Large SSB 0.02 3.0E-09 3.0E-09 Totals = 5.49E-06 1.9E-07 1.9E-07

% of plant CDF 18% 0.6%

Note: No CAT-2 sequences were in the top 38 sequences. An examination of lower CDF sequences indicated that CAT-2 frequency is expected to be at the order of 1E-08, which is used in this table.

A more rigourous calculation can be done by examining the cutsets with B1 and B2 seal failures coincident with AFW failures.

3.9E-09 This EXCEL file RASP Manual Section referring to this document.

Sequence List (4)

Conclusion:

For this selected example plant CDF model, based on the top 33 CDF sequences, about 18% of the CDF would be subject to C-SGTR, as shown below.

These top 33 sequences make up 96% of total plant CDF from internal events. CDF Seqs 1-38 2.95E-05 04/24/2015 0:00 HDL Cat-1 only in 1-38 4.90E-06 VOGTLE SPAR MODEL Dominant Sequence Results HDL Cat-2 only in 1-38 2.09E-07 1-38 39-711 1-711 Cat-4 only in 1-38 3.79E-07 Totals= 3.07E-05 Plant CDF = 2.95E-05 1.15E-06 3.07E-05 Plant CDF % = 96.26% 3.74% 100.00%

RCS RCP Pressure RPS, Event Tree Sequence CDF Description AFW LOOP EDG SLOCA, Category

(/RSD or RCSPRESS OR LOCA LPI)

IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 1 LONSW 04-02-10 1.67E-05 low 182 gpm OK-1

/RCPT, /RSD, /BP1, BP2, HPI, SSC1 2 LOACA 20 2.50E-06 /RPS, AFW, MFW, FAB Fails high cat-1

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, /HPI, 3 LOACA 02-02-03 2.23E-06 low 182 gpm OK-1

/SSC, RHR, LPR

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, HPI, 4 LOACA 02-02-09 1.91E-06 low 182 gpm OK-1

/SSC1, LPI IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 5 LONSW 04-03-10 8.36E-07 high 76 gpm OK-1

/RCPT, /RSD, BP1, /BP2, HPI, SSC1 6 LOACA 19 5.74E-07 /RPS, AFW, MFW, /FAB, SSCR, HPR Fails high cat-1 7 ISL-RHR 3 3.89E-07 ISL-RPT-RHR, /ISL-DIAG, ISL-REC-RHR ISL low OK-3 ATWS Pres.

8 TRANS 21-16 3.79E-07 RPS, RCSPRESS ATWS high cat-4 Spike 9 MLOCA 03 3.49E-07 /RPS, /HPI-ML, /AFW-ATWS, /SSC, HPR, LPR low MLOCA OK-2 10 TRANS 20 3.15E-07 /RPS, AFW, MFW, FAB Fails high cat-1

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, /BP2, OPR-04H, 11 LOOPWR 16-03-10 2.61E-07 Fails Loop Fails high 21 gpm cat-1 DGR-04H, AFW-MAN, SG-DEP-LT

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, BP2, OPR-04H, 12 LOOPWR 16-06 2.18E-07 Late fails Loop Fails high 182 gpm cat-1 DGR-04H IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 13 LONSW 04-04-10 2.09E-07 /RCPT, /RSD, BP1, BP2, HPI-ML, /ACC, /AFW-ATWS, /SSC, lsc 480 gpm cat-2 LPI 14 LOOPGR 15 2.08E-07 /RPS-L, /EPS, AFW-L, FAB-L Fails Loop high cat-1

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, /BP2, OPR-04H, 15 LOOPGR 16-03-10 1.73E-07 Fails Loop Fails high 21 gpm cat-1 DGR-04H, AFW-MAN, SG-DEP-LT 16 LOOPWR 16-45 1.64E-07 /RPS-L, EPS, AFW-B, OPR-04H, DGR-04H Fails Loop Fails high cat-1 17 ISL-RHR 4 1.50E-07 ISL-RPT-RHR, ISL-DIAG ISL low OK-3

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, BP2, OPR-04H, 18 LOOPGR 16-06 1.44E-07 Late fails Loop Fails high 182 gpm cat-1 DGR-04H

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, /HPI, 19 LODCA 02-02-03 1.21E-07 low 182 gpm OK-1

/SSC, RHR, LPR

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, HPI, 20 TRANS 02-02-09 1.19E-07 low 182 gpm OK-1

/SSC1, LPI 21 LOOPSC 15 1.13E-07 /RPS-L, /EPS, AFW-L, FAB-L Fails Loop cat-1

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, BP1, /BP2, /HPI, 22 LOACA 02-03-03 1.12E-07 low 76 gpm OK-1

/SSC, RHR, LPR

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, HPI, 23 LODCA 02-02-09 1.09E-07 low 182 gpm OK-1

/SSC1, LPI 24 LOOPGR 16-45 1.08E-07 /RPS-L, EPS, AFW-B, OPR-04H, DGR-04H Fails Loop Fails cat-1

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, HPI, 25 LODCB 02-02-09 1.06E-07 low 182 gpm OK-1

/SSC1, LPI 26 RXVRUPT 2 1.00E-07 RXVESSEL OK-4 27 MLOCA 10 9.74E-08 /RPS, HPI-ML, /ACC, /AFW-ATWS, /SSC, LPI low MLOCA OK-2 C-SGTR RASP Handbook worksheet CDF sequences to estimate LERF Public v2.xlsx 3 12/03/2018

Sequence List (4)

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, BP1, /BP2, HPI, 28 LOACA 02-03-09 9.54E-08 low 76 gpm OK-1

/SSC1, LPI IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 29 LONSW 04-14-10 8.46E-08 low OK-1 RCPT, HPI-ML, /ACC, /AFW-ATWS, /SSC, LPI

/RPS-L, /EPS, /AFW-L, /PORV-L, LOSC-L, /RSD-L, /BP1, BP2, 30 LOOPGR 02-02-09 8.46E-08 Loop low 76 gpm OK-1

/OPR-02H, /RPS, /AFW, HPI, /SSC1, LPI 31 SLOCA 03 8.38E-08 /RPS, /AFW, /HPI, /SSC, RHR, LPR low SLOCA OK-1 32 SGTR 12 8.23E-08 /RPS, /AFW, /HPI, SGI, REFILL1, ECA SGTR

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, /HPI, 33 TRANS 02-02-03 7.91E-08 low 76 gpm OK-1

/SSC, RHR, LPR

/RPS-L, /EPS, /AFW-L, /PORV-L, LOSC-L, /RSD-L, /BP1, BP2, 34 LOOPSC 02-02-09 7.21E-08 Loop 182 gpm OK-1

/OPR-02H, /RPS, /AFW, HPI, /SSC1, LPI 35 LOOPWR 15 6.64E-08 /RPS-L, /EPS, AFW-L, FAB-L Fails Loop cat-1 36 TRANS 21-14 6.24E-08 RPS, /RCSPRESS, MFW, /AFW-ATWS, BORATION ATWS

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, /HPI, 37 LODCB 02-02-03 5.57E-08 low OK-1

/SSC, RHR, LPR 38 LOMFW 20 5.44E-08 /RPS, AFW, MFW, FAB Fails cat-1

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, BP1, BP2, HPI-ML, 39 LOACA 02-04-12 5.18E-08 Fails 480 gpm

/ACC, AFW-ATWS

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, BP1, BP2, /OPR-02H, 40 LOOPGR 16-10-2 4.81E-08 Loop Fails 480 gpm

/HPI, /SSC, LPR 41 LOCHS 12 4.62E-08 /RPS, AFW, FAB Fails cat-1

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, BP1, BP2, /OPR-02H, 42 LOOPSC 16-10-2 4.10E-08 Loop Fails 480 gpm

/HPI, /SSC, LPR

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, BP2, /OPR-04H, 43 LOOPGR 16-04-2 4.07E-08 Loop Fails

/HPI, /SSC, LPR

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, BP2, /OPR-04H, 44 LOOPGR 16-04-7 4.00E-08 Loop Fails HPI, /SSC, LPI

/RPS, /AFW, /PORV, LOSC, /RCPT, /RSD, /BP1, BP2, HPI, 45 LOACA 02-02-10 3.82E-08 SSC1 46 LOMFW 21-16 3.79E-08 RPS, RCSPRESS cat-4 Pres. Spike 47 LOCHS 13-16 3.22E-08 RPS, RCSPRESS cat-4 Pres. Spike 48 LOACA 21-15 2.86E-08 RPS, /RCSPRESS, MFW, AFW-ATWS Fails 49 SGTR 19 2.84E-08 /RPS, AFW, /HPI, /SGI, FAB Fails SGTR

/RPS-L, /EPS, /AFW-L, /PORV-L, LOSC-L, /RSD-L, /BP1, BP2, 50 LOOPWR 02-02-09 2.71E-08 Loop

/OPR-02H, /RPS, /AFW, HPI, /SSC1, LPI

/RPS-L, /EPS, /AFW-L, /PORV-L, LOSC-L, /RSD-L, /BP1, BP2, 51 LOOPGR 02-05 2.60E-08 Loop OPR-02H, HPI-L 52 ISL-LPI 3 2.27E-08 ISL-RPT-LPI, /ISL-DIAG, ISL-REC-LPI ISL low 53 LOACA 02-14-12 2.12E-08 /RPS, /AFW, /PORV, LOSC, RCPT, HPI-ML, /ACC, AFW-ATWS Fails 54 LOOPPC 15 2.08E-08 /RPS-L, /EPS, AFW-L, FAB-L Fails Loop cat-1

/RPS-L, EPS, /AFW-B, /PORV, /RSD-B, /BP1, /BP2, OPR-04H, 55 LOOPSC 16-03-10 1.99E-08 Fails Loop Fails DGR-04H, AFW-MAN, SG-DEP-LT 56 LODCB 20 1.86E-08 /RPS, AFW, MFW, FAB Fails 57 LLOCA 2 1.79E-08 /ACC, /LPI, LPR-LL LLOCA OK-2 58 SGTR 09 1.72E-08 /RPS, /AFW, /HPI, /SGI, SSC, REFILL1, ECA IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 59 LONSW 04-06-10 1.67E-08

/RCPT, RSD, /BP1, /O1, /BP2, O2, HPI, SSC1 IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 60 LONSW 04-08-10 1.67E-08

/RCPT, RSD, /BP1, O1, /BP2, /O2, HPI, SSC1 IEFT-LONSCW, /RPS, /AFW, /PORV, LOSC-NSW, REC-NSW, 61 LONSW 04-09-10 1.67E-08

/RCPT, RSD, /BP1, O1, /BP2, O2, HPI, SSC1 C-SGTR RASP Handbook worksheet CDF sequences to estimate LERF Public v2.xlsx 4 12/03/2018

Sequence List (4)

OK-1 No C-SGTR challenge because AFW OK; RSD OK (RHR pump operation pressure range is reached in RCS).

OK-2 No C-SGTR challenge because of MLOCA or LLOCA; RCS pressure is not high.

OK-3 No C-SGTR since: AFW is most likely OK (not querried in the ET); RCS likely depressurized either by break size or by operator action.

OK-4 No C-SGTR since low RCS pressure due to vessel failure RSD = Rapid secondary depressurization.

SSC = Cooldown (primary and secondary)

LOSC = RCP seal cooling maintained C-SGTR RASP Handbook worksheet CDF sequences to estimate LERF Public v2.xlsx 5 12/03/2018

Fault Tree Description 1 ACC ACCUMULATOR 3-OF-3 2 AFW AUXILIARY FEEDWATER 3 AFW-ATWS AUXILIARY FEEDWATER 4 AFW-B AUXILIARY FEEDWATER (BLACKOUT) 5 AFW-L VOGTLE AFW USING LOOP-FTF FAULT TREE FLAGS FAULT TREE 6 AFW-MAN MANUAL CONTROL AFW 7 BORATION EMERGENCY BORATION 8 BP1 RCP SEAL STAGE 1 INTEGRITY (BINDING/POPPING) 9 BP2 RCP SEAL STAGE 2 INTEGRITY (BINDING/POPPING) 10 CSI TERMINATE OR CONTROL SAFETY INJECTION 11 CST-REFILL CONDENSATE STORAGE TANK REFILL 12 CST-REFILL-LT CONDENSATE STORAGE TANK REFILL LONG-TERM 13 CST-REFILL-LT1 CONDENSATE STORAGE TANK REFILL LONG-TERM 14 DGR-01H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 1 HOUR 15 DGR-02H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 2 HOURS 16 DGR-03H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 3 HOURS 17 DGR-04H DIESEL GENERATOR RECOVERY (IN 4 HR) 18 DGR-06H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 6 HOURS 19 DGR-08H OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 8 HOURS 20 DGR-30M OPERATOR FAILS TO RECOVER EMERGENCY DIESEL IN 30 MINUTES 21 ECA DECAY HEAT REMOVAL /RECOVERY (ECA-3.1/3.2) 22 EPS EMERGENCY POWER 23 FAB FEED AND BLEED 24 FAB-L VOGTLE FEED AND BLEED IS UNAVAILABLE using LOOP-FTF 25 FAB-NSW FEED AND BLEED IS UNAVAILABLE USING LONSW-FTF 26 FAB2 FEED AND BLEED (1 PORV REQUIRED) 27 HPI HIGH PRESSURE INJECTION 28 HPI-L HIGH PRESSURE INJECTION 29 HPI-ML HIGH PRESSURE INJECTION 30 HPR HIGH PRESSURE RECIRC 31 HPR-L HIGH PRESSURE RECIRC 32 HPR-ML HIGH PRESSURE RECIRCULATION 33 HPR1 HIGH PRESSURE RECIRCULATION 34 IE-ISL-HPI ISLOCA IE 2-CKV HPI interface 35 IE-ISL-LPI ISLOCA IE 2-CKV LPI interface 36 IE-ISL-RHR RHR pipe ruptures

37 IE-LOACCW LOSS OF AUXILIARY COMPONENT COOLING WATER 38 IE-LONSW LOSS OF NUCLEAR SERVICE COOLING WATER 39 IE-LOOP LOSS OF OFFSITE POWER 40 IE-SGTR SG TUBE RUPTURE 41 IE-SLBIC STEAMLINE BREAK INSIDE CONTAINMENT INITIATOR 42 IEFT-LOACW AUXILIARY COMPONENT COOLING WATER (IE FT) 43 IEFT-LONSCW NUCLEAR SERVICE COOLING WATER (IE FAULT TREE) 44 ISL-DIAG Operators fail to diagnose ISLOCA 45 ISL-REC-HPI Operators fail to recover (isolate) ISLOCA 46 ISL-REC-LPI Operators fail to recover (isolate) ISLOCA 47 ISL-REC-RHR Operators fail to recover (isolate) ISLOCA 48 ISL-RPT-HPI HPI pipe ruptures 49 ISL-RPT-LPI LPI pipe ruptures 50 ISL-RPT-RHR RHR/SDC pipe ruptures 51 LOSC RCP SEAL COOLING MAINTAINED 52 LOSC-ACCW LOSS OF SEAL COOLING 53 LOSC-L VOGTLE RCPSL USING LOOP-FTF FAULT TREE FLAGS 54 LOSC-NSW LOSS OF SEAL COOLING 55 LOSC-TT LOSS OF SEAL COOLING (TURBINE TRIP) 56 LPI LOW PRESSURE INJECTION 57 LPI-NSW LOW PRESSURE INJECTION - LONSW 58 LPR LOW PRESSURE RECIRC 59 LPR-LL LOW PRESSURE RECIRCULATION 60 LPR-NSW LOW PRESSURE RECIRCULATION - LONSW 61 MFW MAIN FEEDWATER 62 O1 RCP SEAL STAGE 1 INTEGRITY (O-RING EXTRUSION) 63 O2 RCP SEAL STAGE 2 INTEGRITY (O-RING EXTRUSION) 64 OPR OFFSITE POWER RECOVERY 65 OPR-01H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 1 HOUR 66 OPR-02H OFFSITE POWER RECOVERY IN 2 HRS 67 OPR-03H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 3 HOURS 68 OPR-04H OFFSITE POWER RECOVERY (IN 4 HR) 69 OPR-06H OFFSITE POWER RECOVERY IN 6 HRS 70 OPR-08H OPERATOR FAILS TO RECOVER OFFSITE POWER IN 8 HOURS 71 OPR-30M OPERATOR FAILS TO RECOVER OFFSITE POWER IN 30 MINUTES 72 PORV PORVs ARE CLOSED 73 PORV-B VOGTLE PORVs/SRVs OPEN DURING STATION BLACKOUT 74 PORV-L VOGTLE PORVs/SRVs OPEN DURING LOOP 75 PORV1 VOGTLE PORVS/SRVS OPEN DURING TRANSIENTS (AFW FAILED) 76 PORV2 PORVs ARE CLOSED

77 PWR-REC LATE POWER RECOVERY 78 PWR-REC-06H LATE POWER RECOVERY (6 HR) 79 PWR-REC-07H LATE POWER RECOVERY (7 HR) 80 PWR-REC-09H LATE POWER RECOVERY (9 HR) 81 PWR-REC-15H LATE POWER RECOVERY (15 HR) 82 PWR-REC-24H LATE POWER RECOVERY (24 HR) 83 RCPT REACTOR COOLANT PUMPS TRIPPED 84 RCSPRESS RCS PRESSURE LIMITED 85 REC-NSW NSCW RECOVERY 86 REFILL RWST REFILL 87 REFILL1 RWST REFILL 88 RHR RESIDUAL HEAT REMOVAL 89 RPS REACTOR TRIP 90 RPS-L REACTOR SHUTDOWN 91 RSD RAPID SECONDARY DEPRESSURIZATION (<1710 PSI IN 2 HR) 92 RSD-B RAPID SECONDARY DEPRESS 93 RSD-L RAPID SECONDARY DEPRESS 94 RXVESSEL REACTOR VESSEL RUPTURES 95 SG-DEP-LT DEPRESSURIZE SGs 96 SGI FAULTED STEAM GENERATOR ISOLATION 97 SSC COOLDOWN (PRIMARY & SECONDARY) 98 SSC1 COOLDOWN (PRIMARY & SECONDARY) 99 SSCR SECONDARY SIDE COOLING RECOVERED

Event Tree Initiator Description 1 ISL-HPI IE-ISL-HPI Vogtle SI cold leg discharge ISLOCA 2 ISL-LPI IE-ISL-LPI Vogtle RHR discharge ISLOCA 3 ISL-RHR IE-ISL-RHR Vogtle RHR suction ISLOCA 4 LLOCA IE-LLOCA Vogtle large loss-of-coolant accident 5 LOACA IE-LOACA Vogtle loss of vital ac 1AA02 bus 6 LOACCW IE-LOACCW Vogtle loss of auxiliary component cooling water 7 LOCHS IE-LOCHS Vogtle loss of condenser heat sink 8 LODCA IE-LODCA Vogtle loss of vital dc 1AD1 bus 9 LODCB IE-LODCB Vogtle loss of vital dc 1BD1 bus 10 LOMFW IE-LOMFW Vogtle loss of main feedwater 11 LONSW IE-LONSW Vogtle loss of nuclear service cooling water 12 LOOPGR IE-LOOPGR Vogtle loss of offsite power (Grid related) 13 LOOPPC IE-LOOPPC Vogtle loss of offsite power (Plant Centered) 14 LOOPSC IE-LOOPSC Vogtle loss of offsite power (Switchyard centered) 15 LOOPWR IE-LOOPWR Vogtle loss of offsite power (Weather related) 16 MLOCA IE-MLOCA Vogtle medium loss-of-coolant accident 17 RXVRUPT IE-XLOCA Vogtle reactor vessel rupture 18 SGTR IE-SGTR Vogtle steam generator tube rupture 19 SLOCA IE-SLOCA Vogtle small loss-of-coolant accident 20 TRANS IE-TRANS Vogtle general transient

IE-SGTR CDF Event Sequence CDF Description AFW HPI Dry SG Flagset Tree 32 SGTR 12 8.23E-08 /RPS, /AFW, /HPI, SGI, REFILL1, ECA Yes ETF-SGTR 49 SGTR 19 2.84E-08 /RPS, AFW, /HPI, /SGI, FAB fails Yes ETF-SGTR 58 SGTR 9 1.72E-08 /RPS, /AFW, /HPI, /SGI, SSC, REFILL1, ECA Yes ETF-SGTR 74 SGTR 22 8.88E-09 RPS Yes ETF-SGTR 83 SGTR 20 6.84E-09 /RPS, AFW, /HPI, SGI fails  ? ETF-SGTR 106 SGTR 14 2.70E-09 /RPS, /AFW, HPI, /SGI, /SSC1, RHR fails Yes ETF-SGTR 123 SGTR 18 1.97E-09 /RPS, AFW, /HPI, /SGI, /FAB, HPR fails Yes ETF-SGTR 167 SGTR 6 9.95E-10 /RPS, /AFW, /HPI, /SGI, /SSC, CSI, REFILL, ECA Yes ETF-SGTR 238 SGTR 15 1.90E-10 /RPS, /AFW, HPI, /SGI, SSC1 fails Yes ETF-SGTR 254 SGTR 21 1.44E-10 /RPS, AFW, HPI fails fails Yes ETF-SGTR 287 SGTR 16 9.29E-11 /RPS, /AFW, HPI, SGI fails  ? ETF-SGTR 391 SGTR 3 1.76E-11 /RPS, /AFW, /HPI, /SGI, /SSC, /CSI, RHR, CST-REFILL Yes ETF-SGTR Total= 1.50E-07 ECA DECAY HEAT REMOVAL /RECOVERY (ECA-3.1/3.2)

REFILL REFILL1 RWST REFILL SSC SSC1 COOLDOWN (PRIMARY & SECONDARY)

CSI TERMINATE OR CONTROL SAFETY INJECTION SGI Faulted SG isolation IEV-SGTR = 2.07E-03 CCDP(SGTR) = 7.23E-05 CDF IEV-SGTR = 1.50E-07 CCDP(LSSB) = 1.45E-04 p(csgtr)LSSB = 0.02 IEV-LSSB) = 1.00E-03 CDF(LSSB and CSGTR) = 2.89E-09

SGTR LSSB and C-SGTR Comment on LSSB IEV frequency 2.07E-03 1.0E-03 Rare event, not expected to occur during plan CCDP 7.23E-05 1.45E-04 2 times the CCDP of SGTR due to less favora p(csgtr) 0.02 From Table 2.4-1 CDF 1.50E-07 3.E-09 C-SGTR in SSB Event Tree C-SGTR IE-LSSB RPS CCDP of LSSB End State SSB No C-SGTR Success OK Occurs ~1 C-SGTR 1.00E-03 0.02 CD with C-SGTR 1.45E-04 3.E-09 Fails Transfer to ATWS ET small

ATWS C-SGTR Models IE-TRANS RPS PR-REL AFW FL-DPT P-L/R CCDP End State IE-TRANS RPS PR-REL FL-DPT P-L/R CCDP End State 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Success 1 No ATWS Success 1 No ATWS 1

Yes Small 2 No leak 0.95 Yes. 2200 <

Yes. 2200 < P< 3300 Small 2 No leak Medium 3 CD-Leak P < 3300 Occurs 0.95 0.04 1 1.00E-03 No Medium 3 CD-Leak 1 Large 4 CD-C-SGTR Occurs Fails 0.01 1 0.1 Large 4 CD-C-SGTR 1.00E-05 Fails No. P >3300 5 CD- C-SGTR Yes 0.02 No. P >3300 No 5 CD-C-SGTR Figure 3-1. ATWS Event Tree Top Events to Address TypeII CSGTR IE-TRANS RPS PR-REL AFW FL-DPT P-L/R CCDP End State IEV RPS PR-REL AFW p(sgtr) End State 1 2 3 4 5 6 7 8 Success 1 No ATWS Success 1 No ATWS 1 Occurs Success 2 No C-SGTR Yes Insign. Challenge Success 0.5 3 No C-SGTR Yes. 2200 < P< 3300 Small 2 No leak Fails Fails 9.50E-01 0.95 4 C-SGTR No Medium 3 CD-Leak 9.50E-10 assume SGTR 0.01 Occurs 0.5 0.04 1.00E-02 5 No C-SGTR 1 Large 4 CD-C-SGTR 2.38E-09 Fails Fails 0.01 0.1 6 C-SGTR 5.00E-06 Yes 1.25E-07 0.05 No. P >3300 0.5 5.00E-02 No 5 CD-C-SGTR 1.25E-07 0.5 Sum = 2.5E-07 Figure 32. ATWS Event Tree Top Events to Address TypeII CSGTR - Example Quantification This node represents the probability of getting a small, or a medium, or a large flaw depth, given a 5 FLDPT flaw is originated since the last refueling outage. Any flaws of depth 40% or less are assumed identified and their tubes are plugged, if they have occurred before the last outage.

This node represents the probability of leak or CSGTR given that a flaw with depth specified in the 6 PL/R FLDPT node exists.

This is the CCDP assigned to the sequence defined so far with Node 1 through 6 in the event tree.

7 CCDP This CCDP represents the additional failures needed to reach core damage end state, given that the sequence in question has progressed to the point defined by Nodes 1 through 6.

RCP Seal LOCA Model in SPAR LOSC RCP SEAL COOLING MAINTAINED RCPT REACTOR COOLANT PUMPS TRIPPED RCSPRESS RCS PRESSURE LIMITED RAPID SECONDARY DEPRESSURIZATION RSD

(<1710 PSI IN 2 HR) 480 gpm/pump seal LOCA occurs if LOSP and RCPT OR if LOSC and BP1 and BP2. Then, loop seal clearing occurs.

Table 2.3-1. Probability that a Detected Flaw Belongs to a Bin Size Flaw Length 0 to 1 cm 1 to 2 cm 2 to 3 cm 3 to 4 cm 4 to 5 cm 5 to 6 cm Total 0 to 0.1 2.74E-03 4.62E-02 2.23E-02 5.38E-03 1.04E-03 1.80E-04 7.78E-02 Flaw Depth %/100 0.1 to 0.2 1.86E-02 3.14E-01 1.52E-01 3.66E-02 7.08E-03 1.23E-03 5.30E-01 0.2 to 0.3 9.59E-03 1.62E-01 7.81E-02 1.89E-02 3.64E-03 6.31E-04 2.73E-01 0.3 to 0.4 3.09E-03 5.21E-02 2.52E-02 6.07E-03 1.17E-03 2.03E-04 8.78E-02 8.78E-02 0.4 to 0.5 8.47E-04 1.43E-02 6.90E-03 1.66E-03 3.22E-04 5.57E-05 2.41E-02 2.41E-02 0.5 to 0.6 2.14E-04 3.61E-03 1.74E-03 4.21E-04 8.13E-05 1.41E-05 6.08E-03 6.08E-03 0.6 to 0.7 5.14E-05 8.67E-04 4.19E-04 1.01E-04 1.95E-05 3.38E-06 1.46E-03 1.46E-03 5.43E-04 0.7 to 0.8 1.19E-05 2.01E-04 9.73E-05 2.35E-05 4.54E-06 7.86E-07 3.39E-04 3.39E-04 1.26E-04 0.8 to 0.9 2.71E-06 4.57E-05 2.21E-05 5.32E-06 1.03E-06 1.78E-07 7.70E-05 7.70E-05 2.86E-05 0.9 to 1.0 small Total 3.51E-02 5.93E-01 2.87E-01 6.92E-02 1.34E-02 2.32E-03 1.00E+00 1.00E+00 1.20E-01 6.98E-04