ML14016A097
| ML14016A097 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 01/08/2014 |
| From: | Capps S Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML14016A097 (36) | |
Text
T DUKE
ý ENERGY.
McGuire Nuclear Station Duke Energy 12700 Hagers Ferry Road Huntersville, NC 28078 o: 980.875.4000 January 8, 2014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001
SUBJECT:
Duke Energy Carolinas (DEC), LLC McGuire Nuclear Station (MNS), Units 1 and 2 Docket Numbers 50-369 and 50-370 Supplemental Information for License Amendment Request (LAR) to Adopt National Fire Protection Association (NFPA) 805 Performance-Based Standard for Fire Protection for Light-Water Reactor Generating Plants By letter dated September 26, 2013, DEC submitted a LAR to adopt the NFPA 805 Performance Based Standard for Fire Protection for MNS Units 1 and 2. In an email dated December 18, 2013, the NRC requested DEC supplement the LAR to provide information needed to make the LAR complete. provides the supplemental information requested by the NRC. This supplemental information required minor changes to another section of the LAR as described in Enclosure 2.
Questions regarding this submittal should be directed to Jeff Robertson, McGuire Regulatory Compliance at (980) 875-4499.
I declare under penalty of perjury that the foregoing is true and correct. Executed on January 8, 2014.
Steven D. Capps Enclosure www.duke-energy.com
U.S. Nuclear Regulatory Commission January 8, 2014 Page 2 cc:
Victor M. McCree Regional Administrator U. S. Nuclear Regulatory Commission, Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 John Zeiler Senior NRC Resident Inspector U. S. Nuclear Regulatory Commission McGuire Nuclear Station Jason Paige (Addressee Only)
NRC Project Manager U. S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 0-8 G9A Rockville, MD 20852-2738
ENCLOSURE 1 MNS Response to the NRC December 18, 2013, Request for Supplemental Information for the MNS LAR to Adopt NFPA 805 Performance-Based Standard for Fire Protection
December 18. 2013. NRC Reauest for SuDDlemental Information By letter dated September 26, 2013, Duke Energy Carolinas, LLC submitted a license amendment request for McGuire, Units 1 and 2. The proposed amendment would adopt a new fire protection licensing basis which complies with the requirements in Title 10 of the Code of Federal Regulations (10 CFR), Section 50.48(a), 10 CFR 50.48(c), and the guidance in Regulatory Guide (RG) 1.205, "Risk-Informed, Performance Based Fire Protection for Existing Light-Water Nuclear Power Plants," Revision 1, dated December 2009. The purpose of this email is to provide the results of the U.S. Nuclear Regulatory Commission (NRC) staff's acceptance review of this amendment request. The acceptance review was performed to determine if there is sufficient technical information in scope and depth to allow the NRC staff to complete its detailed technical review. The acceptance review is also intended to identify whether the application has any readily apparent information insufficiencies in its characterization of the regulatory requirements or the licensing basis of the plant.
On December 18, 2013, the NRC staff and Duke Energy held a teleconference to discuss four draft questions generated during the acceptance review. At the conclusion of the call, the staff determined that one of the four questions is necessary to enable the NRC staff to make an independent assessment regarding the acceptability of the proposed amendment request.
Below is the requested information. In order to make the application complete, the NRC staff requests that Duke Energy supplement the application to address the information requested below by January 8, 2014.
- 1. Table W-1 states that the total fire CDF is 2.70E-5/yr for Unit 1 and 3.87E-5/yr for Unit
- 2. Please summarize the principle difference(s) between the Units that cause the different risk estimates. Please also provide a Table of the Unit 2 risk-significant scenarios such as that provide in Table W-2 for Unit 1.
MNS Response to the December 18, 2013, NRC Request for Supplemental Information The difference between the risk estimates for Unit 1 and Unit 2 in Table W-1 of the MNS NFPA 805 LAR dated September 26, 2013, is principally attributable to differences in each Unit's cable routing versus distinct design differences between the Units.
The remaining pages of this Enclosure provide Table W-2-1 and Table W-2-2. Table W-2-2 provides the requested Unit 2 risk significant scenarios. Table W-2-1 provides revisions to the Unit 1 risk significant scenarios provided in the original Table W-2 in the MNS NFPA 805 LAR dated September 26, 2013. Table W-2-2 considers the effect of the Liquid Waste Recycle System (WL) modification and cabinet treatments from Table S-2 of the LAR. The Unit 1 risk significant scenarios were revised to reflect these same considerations.
Tables W-2-1 and W-2-2 in this Enclosure replace the entire original Table W-2 in the MNS NFPA 805 LAR dated September 26, 2013.
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights A Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF /
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 24_C4 MCB 3.6%/3.6%
This scenario is dominated by loss of all 8.48E-01 8.14E-04 1.44E-06 4.5%
3 0.17 MC1/MC2/MC10 SSHR sequences. The fire results in spurious Fire PORV operations on multiple SGs resulting in faulted SGs, and loss of all 3 pressurizer PORVs. Mitigation fails because feed and bleed is unsuccessful with no pressurizer PORVs. This scenario is the #3 LERF contributor with thermally induced SGTR as the primary containment failure mode. Some conservative bias may be present if operator actions to manually close main steam branch lines can reduce the likelihood of a SG being treated as faulted. No credit for such action is taken.
19_lxs 11C10 Input'A' 3.4%/7.0%
This scenario is split between RCP seal 6.12E-02 2.21E-05 1.35E-06 4.1%
4 0.16 Cabinet Fire LOCA and loss of SSHR sequences. The fire results in a loss of MFW, loss of seal injection due to an isolation failure of the FWST or a spurious start of containment sprays, loss of normal power supply to both essential buses and emergency power supply to the A essential bus, loss of CR trip functions, loss of thermal barrier cooling, loss of the LLI supply, loss of RN train A, failure of 1 pressurizer PORV and failure of MSIV closure. Random failures of the SSF and diesels lead to an RCP seal LOCA scenarios. Random failures of the diesels, CA TDP and diesel compressors lead to a loss of all SSHR. This scenario is the #4 LERF contributor with random containment failure due to loss of the igniters or a thermally induced SGTR due to the fire faulting the SGs.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights' Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 19_17s 11C07 Input'A' 3.4% / 10.3%
This scenario behaves the same as scenario 6.12E-02 2.21E-05 1.35E-06 4.1%
5 0.16 Cabinet Fire 19_lxs. The scenario is split between RCP seal LOCA and loss of SSHR sequences.
The fire results in a loss of MFW, loss of seal injection due to an isolation failure of the FWST or a spurious start of containment sprays, loss of normal power supply to both essential buses and emergency power supply to the A essential bus, loss of CR trip functions, loss of thermal barrier cooling, loss of the LLI supply, loss of RN train A, failure of I1 pressurizer PORV and failure of MSIV closure. Random failures of the SSF or diesels lead to challenging the pressurizer PORVs for the RCP seal LOCA scenarios.
Random failures of the diesels, CA TDP and diesel compressors lead to a loss of all SSHR. This scenario is the #5 LERF contributor with random containment failure due to loss of the igniters or a thermally induced SGTR due to the fire faulting the SGs.
TB1_D 1TC Switchgear 3.1% /13.4%
This scenario is split between loss of SSHR 3.02E-03 4.08E-04 1.23E-06 1.9%
7 0.08 Fire and RCP seal LOCA sequences. The fire results in a loss of the normal power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-C, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to seal LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario is the #7 LERF contributor with random containment failure due to loss of the igniters.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-1 Unit 1 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF /
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 9-11_Bl Switchgear 1ETB 2.8% /16.2%
This scenario is dominated by RCP seal 4.56E-03 5.34E-04 1.12E-06 1.1%
28 0.05 Severe Fire LOCA sequences or stuck open pressurizer relief valves The fire results in spurious start of NV pump B, loss of ETB, spurious pressurizer PORV operation, and failure of the SSF standby makeup pump. The spurious NV pump start leads to a pressurizer SRV challenge and failure. Random failures of A train components (mostly maintenance) lead to a loss of seal cooling and seal failure.
The top cutset is the spurious NV pump start sequence which is around 11% of the total.
Note: this scenario is influenced by LC and MCC maintenance on train A which is likely overestimated with the screening value of 1 E-03.
19_J2s 11C02 Input 'B' 2.7% / 18.9%
This scenario is dominated by loss of SSHR 4.84E-02 2.21E-05 1.07E-06 11.2%
1 0.56 Cabinet Fire sequences. The fire causes a loss of MFW, a loss of normal power to the essential buses, loss of emergency power to the A essential bus, loss of thermal barrier cooling, loss of LLI from RN train B, and loss of several PORVs.
Random failures of the diesel compressors and SG alignment lead to a loss of all SSHR.
This scenario is the #1 LERF contributor with random containment failure due to a loss of the igniters.
19_14s 11C04 Input'A' 2.7%/21.5%
This scenario is dominated by RCP seal 4.83E-02 2.21E-05 1.07E-06 3.8%
6 0.19 Cabinet Fire LOCAs. The fire causes a spurious operation of the NV pumps, loss of MFW, loss of seal injection, loss of the VCT, loss of normal power to the essential buses, loss of emergency power to A essential bus and loss of thermal barrier cooling. Random SSF failures lead to a total loss of seal cooling.
This scenario is the #6 LERF contributor with the fire failing the A train of VX.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights "
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
%CDFI LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 15-17_B4 Swgr 1 ETA 2.7% / 24.2%
This scenario is dominated by loss of SSHR 9.84E-03 1.87E-04 1.07E-06 1.8%
8 0.09 Severe Fire with sequences and transient induced pressurizer HEAF (1-6)
SRV LOCAs. The fire results in loss of ETA, and spurious start of the 1A NV pump.
Random failures of train B components lead to core damage. This scenario is the #8 LERF contributor with many random containment failure modes contributing.
TB1_C 1TB Switchgear 2.4% /26.6%
This scenario is split between loss of SSHR 2.40E-03 4.08E-04 9.80E-07 1.5%
14 0.08 Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-B, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario ranks #14 in the LERF contribution with random containment failure due to loss of the igniters being the dominant containment failure modes.
TB1_B 1TA Switchgear 2.3% / 29.0%
This scenario is split between loss of SSHR 2.31 E-03 4.08E-04 9.44E-07 1.5%
15 0.09 Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-A, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario ranks #15 in the LERF contribution with random containment failure due to loss of the igniters being the dominant containment failure modes.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights DueEeg aoias L
tahetW iePAIsgt Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF /
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF TB1_E 1TD Switchgear 2.3% /31.3%
This scenario is split between loss of SSHR 2.31 E-03 4.08E-04 9.44E-07 1.5%
16 0.09 Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-D, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario ranks #16 in the LERF contribution with random containment failure due to loss of the igniters being the dominant containment failure modes.
19_J5s 11C05 Input 'B' 2.3% / 33.7%
This scenario is dominated by RCP seal 4.24E-02 2.21 E-05 9.38E-07 1.0%
30 0.06 Cabinet Fire LOCAs sequences. The fire results in a loss of MFW, loss of seal injection due to an isolation failure of the FWST and failure of the VCT, loss of normal power to the essential buses, loss of CR trip function and loss of thermal barrier cooling. Random failures of the SSF lead to a loss of all seal cooling.
15-17_Cl Load Center 2.2%/35.8%
This scenario is dominated by RCP seal 2.OOE-02 8.16E-05 8.64E-07 1.1%
25 0.07 1 ELXA Severe LOCAs. The fire results in failure of ETA, the Fire SSF SMUP, and letdown isolation. Random failures of train B (RN and KC) results in loss of seal cooling and failure to mitigate the seal LOCA.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights '
Due neg Caoins LL tahetW-iePAIsgt Table W-2-1 Unit 1 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDFI LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF SRVB 1SLXA/B/C/D 2.1% / 37.9%
This scenario is split between seal LOCAs 4.31 E-03 1.97E-04 8.48E-07 1.5%
17 0.09 Load Center and total loss of SSHR sequences. The fire Severe Fire results in a loss of offsite power to both essential switchgear, loss of MFW, loss of the CR RCP trip on RCP-C, and a loss of the LLI supply to RN train B. Random failures of the DGs lead to an SBO condition. Various TDCAP failures (mostly failure to locally throttle following a loss of IA) or SSF SMUP failures lead to core damage.
21_Bi MCC 1/2EMXA 2.1% /40.0%
This scenario is dominated by RCP seal 7.97E-03 5.31E-04 8.46E-07 0.7%
39 0.04 Severe Fire LOCA sequences. The fire results in FWST draining or isolation (FW27A), loss of the VCT, and loss of thermal barrier cooling.
Random failure of the SSF results in total loss of seal cooling. Failure to trip the RCP leads to the large seal LOCA where other sizes may occur if the RCPs are tripped. Mitigation fails due to loss of the FWST or random recirculation failure.
TB1_0 Turbine Generator 2.1%/42.1%
This scenario is split between loss of SSHR 1.54E-03 3.18E-03 8.33E-07 1.5%
19 0.09 Hydrogen Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, and loss of the LLI supply to RN train B.
Random DG failure leads to loss of all power. Random failure of the SSF leads to seal LOCA or random failure of the TDCAP leads to loss of SSHR. Mitigation fails due to the loss of power.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights DueEeryCrliaLC tahmn Fr R
Isgt Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
%CDFI LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 15-17_B5 Swgr 1ETA 2.0% /44.1%
This scenario is dominated by transient 1.08E-02 1.60E-04 7.99E-07 1.4%
20 0.09 Severe Fire with induced LOCAs and loss of SSHR HEAF (7-11) sequences. The fire results in loss of ETA, loss of the normal power supply to ETB, and spurious pressurizer spray or NV pump start.
Failure to mitigate excess injection flow leads to a stuck open pressurizer SRV. Random failures of CA train B and the TDCAP lead to loss of SSHR. Mitigation fails due to random failures affecting sump recirculation.
19_K4s 11C12 Input NE 2.0% /46.1%
This scenario is dominated by a loss of SSHR 3.57E-02 2.21E-05 7.89E-07 5.2%
2 0.35 Cabinet Fire sequences. The fire results in a loss of MFW, loss of seal injection due to an isolation failure of the FWST and failure of the VCT, loss of normal power to the essential buses, loss of emergency power to the A essential bus, loss of thermal banier cooling, loss of the LLI supply to RN train B, and spurious PORV operations on multiple SGs. Random failures of the diesels and RN supply result in a loss of all SSHR. This scenario is the #2 LERF contributor with the fire failing A train VX.
15-17_B6 Swgr 1 ETA 1.8% /47.9%
This scenario is split between transient 8.37E-03 1.87E-04 7.23E-07 1.3%
22 0.10 Severe Fire with induced stuck open pressurizer SRV, RCP HEAF (12-17) seal LOCAs, and loss of SSHR sequences.
The fire results in failure of ETA, spurious start of NV pump A, and inability to trip RCPs A and C from the CR. The spurious NV pump start leads to a pressurizer SRV challenge and failure. Random failures of B train components lead to failure to mitigate the transient.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights DueEeryCrliaLC tahmn Fr R
Isgt Table W-2-1 Unit 1 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF TB1_K 1LXF Load Center 1.7% / 49.6%
This scenario is split between loss of SSHR 3.82E-03 1.79E-04 6.85E-07 1.2%
24 0.09 Fire and RCP seal LOCA sequences with loss of SSHR being a somewhat larger contributor.
The fire results in a loss of the normal power supply to both essential buses, loss of MFW, and loss of the LLI supply to RN train B.
Random failures of the DGs or their support systems results in a loss of all power.
Random failures of the SSF or the TDCAP lead to core damage.
TB1_L 1 LXG Load 1.6% / 51.1%
This scenario is dominated by reactor coolant 3.52E-03 1.79E-04 6.31 E-07 1.0%
29 0.09 Center Fire pump seal LOCAs. The fire results in a loss of offsite power to both trains of the essential switchgear, the SSF standby makeup pump, CR trip of RCP-D, and the LLI supply to train B of RN. Random DG failures lead to a seal LOCA with no available mitigation. Loss of SSHR sequences due to TDCAP failures also make a small contribution.
13_SA KXA Static 1.5% /52.6%
This scenario is dominated by RCP seal 1.45E-01 4.42E-05 6.04E-07 1.1%
26 0.10 Inverter Fire LOCAs; loss of SSHR sequences do contribute. The fire results in loss of power to 1 ETB, normal power to 1 ETA, the TDCAP, thermal barrier cooling, suction sources for the NV pumps, and sump recirculation. Loss of the SSF leads to seal LOCAs; random failures of the available CA equipment lead to loss of SSHR. Mitigation fails at sump recirculation.
21_Y1 Transient Fire at 1.5% / 54.1%
This scenario is dominated by loss of all 2.27E-01 2.62E-06 5.93E-07 1.8%
9 0.16 Risers near HH-SSHR sequences. The fire results in spurious 54 PORV operations on multiple SGs resulting in faulted SGs, and loss of sump recirculation.
Mitigation fails because of the loss of sump recirculation. This scenario is the #9 LERF contributor with spurious VX and thermally induced SGTR as the primary containment failure modes.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights DueEeg aoias L
tahetW iePAIsgt Table W-2-1 Unit 1 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
%CDFI LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 1911s 11COl Input'A' 1.4% / 55.5%
This scenario is split between loss of all 2.56E-02 2.21E-05 5.67E-07 1.6%
13 0.15 Cabinet Fire SSHR and RCP seal LOCAs. The fire results in a loss of MFW, loss of seal injection due to FWST draining or isolation, loss of VCT, loss of normal power to the essential buses and loss of emergency power to the A essential bus, loss of LLI to RN train B and loss of thermal barrier cooling. Random failures of the SSF results in total loss of seal cooling.
Failure to trip the RCP leads to the large seal LOCA where other sizes may occur if the RCPs are tripped. This scenario is the #13 LERF contributor with the fire failing the A VX train.
TB1_J 1LXE Load Center 1.4% / 56.9%
This scenario is split between loss of SSHR 3.16E-03 1.79E-04 5.66E-07 0.9%
31 0.08 Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, loss of the CR trip on RCPs C and D, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights '
Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-1 Unit 1 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF /
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 13_Y1 Transient Fire 1.3% / 58.3%
This scenario is a mix of RCP seal LOCA and 1.55E-01 3.42E-06 5.32E-07 1.7%
12 0.17 near EE-56 loss of all SSHR sequences. The fire results in loss of normal power to both essential busses, FWST draining, loss of the VCT, and loss of thermal barrier cooling. Random failure of the SSF results in total loss of seal cooling. Failure to trip the RCP leads to the large seal LOCA where other sizes may occur if the RCPs are tripped. Random failure of the TDCAP leads to loss of SSHR. Failure to terminate the FWST drain leads to loss of the ECCS pumps and mitigation capability. This scenario is the #12 LERF contributor with spurious VX and random containment failure as the primary containment failure modes.
20_J4s 21C11 Input 'B' 1.2% / 59.4%
This scenario is split between RCP seal 2.11E-02 2.21E-05 4.65E-07 1.3%
23 0.15 Cabinet Fire LOCA and loss of SSHR sequences. The fire results in a loss of LLI supply to RN, loss of SNSWP to RN train A and prevents RN from being recovered from the opposite unit. The loss of RN causes the operators to start the SSF and random failures of the SSF lead to a loss of seal cooling or failing to throttle the CA TDP leads to overfilling the SGs.
TB1_G 1LXB Load Center 1.2% / 60.6%
This scenario is split between loss of SSHR 2.58E-03 1.79E-04 4.63E-07 0.7%
35 0.08 Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, loss of the CR trip of multiple RCPs, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures following SSF SMUP failure lead to seal LOCAs. TDCAP failure leads to loss of all SSHR. Mitigation is failed due to the loss of power.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
%CDF/
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF TB1_F 1LXA Load Center 1.1% /61.7%
This scenario is split between loss of SSHR 2.53E-03 1.79E-04 4.53E-07 0.7%
36 0.08 Fire and RCP seal LOCA sequences. The fire results in a loss of the offsite power supply to both essential buses, loss of MFW, loss of the CR trip of multiple RCPs, and loss of the LLI supply to RN train B. DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures following SSF SMUP failure lead to seal LOCAs. TDCAP failure leads to loss of all SSHR. Mitigation is failed due to the loss of power.
19_F Status Light 1.1% / 62.8%
This scenario is dominated by loss of all 2.02E-02 2.21 E-05 4.47E-07 1.7%
10 0.20 Cabinet Fire SSHR sequences. The fire results in a loss of MFW, loss of normal power to the essential buses, loss of thermal barrier cooling, loss of the LLI to the B RN train and failures of the valves needed to swap to sump recirculation.
Random failures of the diesel compressors and diesels lead to a loss of all SSHR. This scenario is the #10 LERF contributor with the fire causing a spurious failure of the A VX train.
19_G Annunciator 1.1% / 63.9%
This scenario behaves the same as scenario 2.02E-02 2.21 E-05 4.47E-07 1.7%
11 0.20 Cabinet Fire 19_F. This scenario is dominated by loss of all SSHR sequences. The fire results in a loss of MFW, normal power to the essential buses, loss of thermal barrier cooling, loss of the LLI to the B RN train and failures of the valves needed to swap to sump recirculation.
Random failures of the diesel compressors and diesels lead to a loss of all SSHR. This scenario is the #11 LERF contributor with the fire causing a spurious failure of the A VX train.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-1 Unit I Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 2_DA Aux Shutdown 1.0% /64.9%
This scenario is dominated by RCP seal 3.51 E-02 1.11E-05 3.88E-07 0.3%
67 0.04 Panel Fire (A LOCAs and stuck open pressurizer relief Train) valves. The fire results in loss of RN, spurious operation of the NV pumps. Failure to recover RN from RV and Unit 2 results in complete loss of RN. SSF failure leads to a seal LOCA. Mitigation fails due to the loss of RN.
Notes:
- a. Individual contribution followed by cumulative contribution.
- b. Ignition Frequency (IF) includes severity factor and probability of non-suppression, where applicable.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 20_J5s 21C05 Input 'B' 7.4% /7.4%
This scenario is dominated by loss of SSHR 2.26E-01 2.21 E-05 3.84E-06 4.3%
4 0.06 Severe Fire sequences. The fire results in a loss of MFW, loss of seal injection due to an isolation failure of the FWST and failure of the VCT, loss of RN assured source, loss of the MD CAP, loss of the PORV block valves and loss of thermal barrier cooling. Random failures of the diesel compressors and failure to throttle the TD CAP result in a total loss of SSHR. This scenario is the #4 LERF contributor with random failures of the hydrogen igniters.
16-18_R RCP-2C Breaker 7.1% /14.5%
This scenario is dominated by RCP seal 4.26E-02 1.26E-04 3.70E-06 2.4%
9 0.03 Fire LOCA sequences. The fire results in a loss of MFW, loss of the SSF SMUP, loss of ETA, loss of CR trip of 1 or more RCPs and the failure of one pressurizer PORV. Random failures of the B train equipment and failure to isolate the SSF letdown line lead to a loss of seal cooling. This scenario is the #9 LERF contributor with random failures of the hydrogen igniters.
20_F Status Light 4.6% /19.1%
This scenario is split between RCP seal 1.21E-01 2.21E-05 2.38E-06 3.5%
7 0.07 Cabinet Fire LOCA, cycling relief valves, and stuck open PORV sequences. The fire results in a loss of MFW, loss of seal injection due to failure of the VCT and the fire diverting the FWST inventory, loss of normal power to the essential buses, loss of ETA, loss of thermal barrier cooling, loss of the LLI to RN and spurious actuation of the SG PORVs.
Combinations of random and fire induced failures lead to the other functional failures.
This scenario is the #7 LERF contributor with the fire failing the VQ line.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 20_J4s 21C11 lnput'B' 4.3%/23.4%
This scenario is split between RCP seal 1.01E-01 2.21E-05 2.24E-06 8.1%
1 0.18 Cabinet Fire LOCA and loss of SSHR sequences. The fire results in a loss of ETA, a loss of thermal barrier cooling, a loss of LLI supply to RN, loss of SNSWP to RN train A and prevents RN from being recovered from the opposite unit. Random failures on train B lead to loss of seal cooling or CAMDP causing the operators to start the SSF and random failures of the SSF lead to a loss of seal cooling or failing to throttle the CA TDP leads to overfilling the SGs. This scenario is the #1 LERF contributor dominated by random containment failure following loss of the igniters with a small contribution from fire failing the VQ line.
14_Y5 Transient Fire -
2.8% /26.2%
This scenario is dominated by loss of all 3.50E-01 4.16E-06 1.46E-06 3.4%
8 0.12 Cable Tray SSHR sequences. The fire results in a loss of Access East MFW, loss of seal injection due to an isolation failure of the FWST and failure of the VCT, loss of ETB, spurious operation of the SG PORVs and failure of all the pressurizer PORVs. Fire induced failures in the CA and SV Systems lead to a loss of all SSHR. This scenario is the #8 LERF contributor dominated by thermally induced SGTR.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF /
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 24_C4 MCB 2.8% /29.0%
This scenario is dominated by loss of all 8.45E-01 8.14E-04 1.44E-06 5.1%
2 0.18 MC1/MC2/MC10 SSHR sequences. The fire results in spurious Fire PORV operations on multiple SGs resulting in faulted SGs, valve impacts in the CA System, and loss of all 3 pressurizer PORVs.
Mitigation fails because feed and bleed is unsuccessful with no pressurizer PORVs.
This scenario is the #2 LERF contributor with thermally induced SGTR as the primary containment failure mode. Some conservative bias may be present if operator actions to manually close main steam branch lines can reduce the likelihood of a SG being treated as faulted. No credit for such action is taken.
20_14s 21C04 Input 'A' 2.6% / 31.5%
This scenario is split between loss of SSHR 6.00E-02 2.21 E-05 1.33E-06 4.0%
5 0.15 Cabinet Fire and RCP seal LOCA sequences. The fire causes a loss of MFW, loss of seal injection due to a failure of the NV supply, loss of ETA, loss of normal power to the B essential bus, loss of CA supply from the RN assured source, loss of CR trip function to one or more RCPs and loss of thermal barrier cooling.
Random or fire induced failures lead to loss of all seal cooling or loss of SSHR. Mitigation fails due to random failures in the ECCS train B and its support systems. This scenario is the #5 LERF contributor from a combination of thermally induced SGTR and random containment failure due to loss of the igniters.
20_11s 21C01 Input'A' 2.2%/33.7%
This scenario behaves similarly to scenario 5.26E-02 2.21E-05 1.16E-06 3.5%
6 0.15 Cabinet Fire 20_14s. Scenario 14s also has impacts to the sump isolation valves causing a slightly higher CCDP fir that scenario. This scenario is the
- 6 LERF contributor from a combination of thermally induced SGTR and random containment failure due to loss of the igniters.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights '
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 10-12_Bl Switchgear 2ETB 2.1% /35.9%
This scenario is dominated by stuck open and 4.44E-03 5.34E-04 1.10E-06 0.8%
28 0.04 Severe Fire cycling pressurizer relief valve sequences.
The fire results in spurious start of NV pump B, loss of ETB, spurious pressurizer PORV operation, and failure of the SSF standby makeup pump. The spurious NV pump start leads to a pressurizer SRV challenge and failure. Random failures of CA train A and other independent failures leading to loss of feed and bleed lead to core damage.
20_J8s 21C08 Input 'B' 2.1%/37.9%
This scenario is dominated by RCP seal 4.89E-02 2.21E-05 1.08E-06 2.4%
10 0.11 Cabinet Fire LOCAs. The fire results in failure of ETB and loss of the normal power source to ETA.
Random failures of train A, the SSF and actions to trip the RCPs lead to seal LOCAs.
Mitigation fails as a consequence of the failures that lead to the loss of train A seal cooling. This scenario ranks as #10 in LERF with containment failures due to loss of the igniters as the primary containment failure mode.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF !
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 20_lxs 21C10 Input 'A' 1.9% /39.9%
This scenario is split between RCP seal 4.53E-02 2.21E-05 1.OOE-06 4.7%
3 0.23 Cabinet Fire LOCA and loss of SSHR sequences. The fire results in a loss of MFW, loss of seal injection due to an isolation failure of the FWST or a spurious start of containment sprays, loss of normal power supply to both essential buses and emergency power supply to the A essential bus, loss of CR trip functions, loss of thermal barrier cooling, loss of the LLI supply, loss of RN train A, failure of 1 pressurizer PORV and failure of MSIV closure. Random failures lead to loss of seal cooling or SSHR and inability to mitigate the transient. This scenario is the #3 LERF contributor with random containment failure due to loss of the igniters or a thermally induced SGTR due to the fire faulting the SGs.
16-18_B6 Swgr 2ETA 1.9% /41.8%
This scenario is dominated by RCP seal 1.14E-02 1.87E-04 9.89E-07 1.0%
22 0.05 Severe Fire with LOCAs with a contribution from stuck open HEAF (12-17)
PZR relief valves. The fire results in failure of ETA, spurious start of NV pump A, and inability to trip RCPs A and C from the CR.
The spurious NV pump start leads to a pressurizer SRV challenge and failure.
Random failures of B train components lead to loss of seal cooling and failure to mitigate the transient.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERFICDF 13_SX SKX Static 1.8%/43.6%
This scenario is dominated by RCP seal 9.15E-02 4.42E-05 9.47E-07 1.1%
20 0.06 Inverter Fire LOCA with a contribution from stuck open PZR relief valves. The fire results in failure of ETB and loss of the normal power source to ETA, high pressure recirculation, and all seal cooling. Random failures of the SSF and actions to trip the RCPs lead to seal LOCAs.
Spurious valve operation leads to uncontrolled injection challenging the PZR relief valves. Mitigation fails as a consequence of the loss of HPR.
TB2_D 2TC Switchgear 1.8% /45.4%
This scenario is split between loss of SSHR 2.29E-03 4.08E-04 9.34E-07 1.8%
14 0.09 Fire and RCP seal LOCA sequences. The fire results in a loss of the normal power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-C, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to seal LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario is the #14 LERF contributor with random containment failure due to loss of the igniters.
16-18_Cl Load Center 1.6% /47.0%
This scenario is dominated by RCP seal 1.98E-02 8.16E-05 8.52E-07 0.5%
44 0.03 2ELXA Severe LOCAs and loss of SSHR. The fire results in Fire failure of ETA, the SSF SMUP, and letdown isolation. Random failures of train B (RN and KC) results in loss of seal cooling and failure to mitigate the seal LOCA.
Random and fire failures affecting CA lead to loss of SSHR and mitigation capability.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
%CDF/
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 16-18_B4 Swgr 2ETA 1.6% /48.6%
This scenario is dominated by RCP seal 9.77E-03 1.87E-04 8.44E-07 0.6%
37 0.04 Severe Fire with LOCAs and loss of SSHR. The fire results in HEAF (1-6) failure of ETA, the SSF SMUP, and letdown isolation. Random failures of train B (RN and KC) results in loss of seal cooling and failure to mitigate the seal LOCA.
Random and fire failures affecting CA lead to loss of SSHR and mitigation capability.
20_17s 21C07 Input 'A' 1.6% / 50.3%
This scenario is split between RCP seal 3.80E-02 2.21E-05 8.40E-07 1.9%
12 0.11 Cabinet Fire LOCA and loss of SSHR sequences. The fire results in a loss of MFW or a spurious start of containment sprays, loss of normal power supply to both essential buses and emergency power supply to the A essential bus, loss of CR trip functions, loss of thermal barrier cooling, loss of the LLI supply, loss of RN train A, failure of 1 pressurizer PORV and failure of MSIV closure. Random failures of the SSF and diesels lead to an RCP seal LOCA scenarios. Random failures of the diesels, CA, TDP and diesel compressors lead to a loss of all SSHR. This scenario is the #12 LERF contributor with random containment failure due to loss of the igniters or a thermally induced SGTR.
21_BI MCC 1/2EMXA 1.6% / 51.9%
This scenario is dominated by RCP seal 7.86E-03 5.31 E-04 8.34E-07 0.7%
35 0.04 Severe Fire LOCA sequences. The fire results in FWST draining or isolation (FW27A), loss of the VCT, and loss of thermal barrier cooling.
Random failure of the SSF results in total loss of seal cooling. Failure to trip the RCP leads to the large seal LOCA where other sizes may occur if the RCPs are tripped. Mitigation fails due to loss of the FWST or random recirculation failure.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF /
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 13_CD Battery Charger 1.6% / 53.5%
This scenario is dominated by RCP seal 3.23E-02 1.29E-04 8.33E-07 0.4%
52 0.03 EVCD Severe Fire LOCAs with some contribution from stuck open pressurizer relief valve sequences. The fire results in failure of ETB, high pressure recirculation, spurious NV pump starts, pressurizer heater operation, and loss of normal seal injection. Random failures of the SSF and actions to trip the RCPs lead to seal LOCAs.
Random relief valve failures can lead to relief valve LOCAs. Mitigation fails as a consequence of the loss of HPR.
16-18_B5 Swgr 2ETA 1.6% /55.0%
This scenario is dominated by RCP seal 1.10E-02 1.60E-04 8.13E-07 0.9%
26 0.05 Severe Fire with LOCAs with some contribution from transient HEAF (7-11) induced LOCAs. The fire results in loss of ETA, loss of the normal power supply to ETB, and spurious pressurizer spray or NV pump start. Random failure to mitigate excess injection flow leads to a stuck open pressurizer SRV. Random failures of train B and the SSF leads to loss of seal cooling.
Mitigation fails due to random failures affecting sump recirculation.
TB2_C 2TB Switchgear 1.4% /56.5%
This scenario is split between loss of SSHR 1.81E-03 4.08E-04 7.39E-07 1.5%
15 0.10 Fire and RCP seal LOCA sequences. The fire results in a loss of the normal power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-B, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario ranks #15 in the LERF contribution with random containment failure due to loss of the igniters.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights -
Duke Energy Carolinas, LLC Attachment W -
Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF b
LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF TB2_B 2TA Switchgear 1.3% / 57.7%
This scenario is split between loss of SSHR 1.76E-03 3.77E-04 6.64E-07 1.4%
18 0.10 Fire and RCP seal LOCA sequences. The fire results in a loss of the normal power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-A, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario ranks #18 in the LERF contribution with random containment failure due to loss of the igniters.
TB2_E 2TD Switchgear 1.3% /59.0%
This scenario is split between loss of SSHR 1.76E-03 3.77E-04 6.64E-07 1.4%
19 0.10 Fire and RCP seal LOCA sequences. The fire results in a loss of the normal power supply to both essential buses, loss of MFW, loss of the CR trip on RCP-D, and loss of the LLI supply to RN train B. Random DG failures lead to a loss of all 4kV power. Failure to trip the RCP or RCP seal failures lead to LOCAs or TDCAP failure leads to loss of all SSHR.
Mitigation is failed due to the loss of power.
This scenario ranks #19 in the LERF contribution with random containment failure due to loss of the igniters.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights "
Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
Scenario 20_K3s Description 21C03 Input NE Cabinet Fire
%CDF/
Cumulative a Risk insights CCDP IF b CDF
% LERF LERF Rank LERFICDF Tabl W--4Ui 2
infcn ieIiitn vns Idvdal ersnig>%o CacltdFr ik 1.2% /60.2%
This scenario is dominated by RCP seal LOCAs, stuck open and cycling pressurizer relief valves, and loss of SSHR. The fire results in loss of MFW, loss of ETA, loss of the offsite power supply to the B train essential bus, loss of thermal barrier cooling and a spurious ADV. Independent failures of the SSF, aligning offsite power from Unit 1 and B diesel lead to RCP seal LOCAs.
Spurious injection challenges relief valves, and random CA failures lead to loss of SSHR.
Mitigation fails due to random failures (mostly power). This scenario ranks #13 in the LERF contribution with random containment failure due to loss of the igniters being the dominant containment failure mode.
2.80E-02 2.21E-05 16.18E-07 1.8%
13 0.14 3_DA Aux Shutdown 1.2% / 61.4%
This scenario is dominated by RCP seal 5.52E-02 1.11E-05 6.10E-07 0.4%
54 0.03 Panel Fire (A LOCAs and stuck open pressurizer relief Train) valves. The fire results in loss of RN, spurious operation of the NV pumps. Failure to recover RN from RV and Unit 1 results in complete loss of RN. SSF failure leads to a seal LOCA. Mitigation fails due to the loss of RN.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-2-2 Unit 2 Significant Fire Initiating Events (Individually Representing >1% of Calculated Fire Risk)
% CDF I LERF Scenario Description Cumulative a Risk insights CCDP IF b CDF
% LERF Rank LERF/CDF 13_CC Battery Charger 1.2% / 62.5%
This scenario is dominated by RCP seal 2.32E-02 1.29E-04 5.99E-07 0.4%
62 0.03 EVCC Severe Fire LOCAs with some contribution from stuck open pressurizer relief valves. The fire results in loss of MFW, normal seal injection, Train A MD CA pump, high pressure ECCS injection, thermal barrier cooling, Train B RN, failure of the pressurizer PORVs to open and Train B diesel. Failure of the SSF to provide seal cooling leads to a seal LOCA. Failure to throttle ECCS leads to a stuck open relief valve. Mitigation fails due to a combination of random and fire induced failures of the recirculation function.
13_SB KXB Static 1.0% / 63.6%
This scenario is split between cycling 1.31 E-01 4.42E-05 5.43E-07 1.9%
11 0.18 Inverter Fire pressurizer relief valves and RCP seal LOCAs. The fire results in a loss of normal seal injection, loss of normal power to Train A essential bus, loss of ETB, loss of TD and MD Train B CA pumps, loss of thermal barrier cooling, loss of all ECCS injection, loss of Train B RN and failure of the pressurizer PORVs to open. Failures of the A diesel and SSF lead to a seal LOCA. Failure of the A train MD CA pump leads to a loss of SSHR.
Mitigation fails mostly due to loss of power following DG failure. This scenario ranks #11 in the LERF contribution with thermally induced SGTR or loss of the igniters being the dominant containment failure modes.
Notes:
- a. Individual contribution followed by cumulative contribution.
- b. Ignition Frequency (IF) includes severity factor and probability of non-suppression, where applicable.
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ENCLOSURE 2 Changes Needed to Other Information in the September 26, 2013, MNS NFPA 805 LAR as Identified During Development of the Response to the NRC Supplemental Information Request.
The supplemental information provided in Enclosure 1 of this submittal required minor changes to Section W.1 on page W-2 of the September 26, 2013, MNS NFPA 805 LAR. The original text in Section W.1 of the LAR discussed Unit 1 results, and because the Unit 2 results were similar, it indicated a table specific to Unit 2 was not provided in the LAR. Revision of this Section W.1 text is required since the Unit 2 results are now being provided as part of this supplemental information request. The revised page W-2 of the LAR incorporating the changes to Section W.1 is included in this Enclosure 2. The revised page W-2 replaces the original page W-2 in the September 26, 2013, MNS NFPA 805 LAR.
The new Tables W-2-1 and W-2-2 provided in Enclosure 1 of this submittal require new page numbers be assigned to the September 26, 2013, MNS NFPA 805 LAR pages containing Tables W-3 and W-4. The revised pages containing these Tables are provided in this Enclosure 2 and replace the original Table W-3 and Table W-4 pages in the September 26, 2013, MNS NFPA 805 LAR. Note, the only changes to the Table W-3 and Table W-4 pages are the page numbers.
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights WA1 Fire PRA Overall Risk Insights Risk insights were documented as part of the development of the Fire PRA. The total plant fire CDF/LERF was derived using the NUREG/CR-6850 methodology for Fire PRA development and is useful in identifying the areas of the plant where fire risk is greatest.
The risk insights generated were useful in identifying areas where specific contributors might be mitigated via modification. A detailed description of significant risk sequences associated with the fire initiating events that represent a 1 % contribution of the calculated fire risk for the plant was prepared for the purposes of gaining these insights and an understanding of the risk significance of MSO combinations. These insights are provided in Table W-2-1 and Table W-2-2 for Unit 1 and Unit 2 respectively.
W.2 Risk Change Due to NFPA 805 Transition In accordance with the guidance in Regulatory Position 2.2.4.2 of RG 1.205 Revision 1:
"The total increase or decrease in risk associated with the implementation of NFPA 805 for the overall plant should be calculated by summing the risk increases and decreases for each fire area (including any risk increases resulting from previously approved recovery actions). The total risk increase should be consistent with the acceptance guidelines in Regulatory Guide 1.174. Note that the acceptance guidelines of Regulatory Guide 1.174 may require the total CDF, LERF, or both, to evaluate changes where the risk impact exceeds specific guidelines. If the additional risk associated with previously approved recovery actions is greater than the acceptance guidelines in Regulatory Guide 1.174, then the net change in total plant risk incurred by any proposed alternatives to the deterministic criteria in NFPA 805, Chapter 4 (other than the previously approved recovery actions), should be risk-neutral or represent a risk decrease."
W.2.1 Methods Used to Determine Changes in Risk The methods and data used to develop the Fire PRA models of the post-transition plant and the compliant plant are consistent with those that underwent the Fire PRA peer review.
The variances from deterministic requirements (VFDRs) are categorized into pre-transition OMAs, separation issues or degraded fire protection systems or features.
MNS VFDR's are only pre-transition OMAs or separation issues. To calculate the delta risk of a given VFDR, the Fire PRA relies on the list of fire-damaged cables and equipment identified during the VFDR identification phase to model the compliant plant.
These cables and equipment are, therefore, at the origin of a delta risk between the post-transition plant and the compliant plant.
The variant case represents the post-transition condition and includes a risk-informed strategy that utilizes failure probabilities for recovery actions, plant modifications, or a combination, to mitigate the risk of the VFDRs. The variant condition represents the
'post-transition' plant configuration, not the currently existing as-built as-operated plant configuration. The variant condition includes the proposed modifications, which include modifications that reduce plant risk, but are not directly related to any particular VFDR.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-3 MNS Unit 1 Fire Area Risk Summary Fire Area Description NFPA Fire Area Fire Area VFDR RAs Fire Risk Eval Fire Risk Eval Additional Risk Offset Risk Area 805 CDF LERF (Yes/No) (Yes/No)
A CDF5 A LERF5 of RAs (WL Mod)
Basis A LERF 1
2 2A 4
5 6
Auxiliary Building Common El 695 Unit 1 Motor Driven CA Pump Room Unit 1 Turbine Driven CA Pump Room Auxiliary Building Common El 716 Unit 1 Train A Diesel Generator Room Unit 1 Train B Diesel Generator Room 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 2.17E-09 7.84E-07 4.73E-07 2.88E-07 5.42E-08 5.84E-08 2.01 E-09 3.13E-08 1.24E-08 1.22E-08 1.58E-08 1.65E-08 Yes Yes Yes Yes Yes Yes No No No Yes No No 2.17E-09 2.37E-07 2.53E-07 1.00E-09 0.OOE+00 0.OOE+00 2.01 E-09 5.60E-09 6.67E-09 1.OOE-10 0.OOE+00 0.OOE+00 N/A N/A N/A 1.00E-09/1.00E-10 N/A N/A 0.OOE+00 2.00E-10 2.OOE-10 1.20E-09 2.1 OE-09 4.90E-09 Unit 1 Train B 9-11 Electrical Penetration 4.2.4.2 1.63E-06 8.92E-08 Yes No 1.55E-06 2.72E-08 N/A 4.48E-08
& Switchgear Rooms 13 Battery Rooms 4.2.4.2 2.98E-06 3.98E-07 Yes Yes 6.30E-07 1.06E-07 6.30E-07/1.06E-07 6.1OE-08 Common 14 Auxiliary Building 4.2.4.2 2.67E-07 1.99E-08 Yes Yes 0.00E+00 0.00E+00 0.00E+00/0.OOE+00 6.OOE-10 Common El 733 Unit 1 Train A 15-17 Electrical Penetration 4.2.4.2 6.12E-06 5.08E-07 Yes No 2.90E-07 1.00E-08 N/A 1.24E-07
& Switchgear Rooms Unit 1 Train A 17A Switchgear HVAC 4.2.4.2 1.90E-07 1.04E-08 Yes No 1.90E-07 1.04E-08 N/A 4.80E-09 Room 5 When used in the context of delta risk, 0.OOE+00 is defined as negligible. For this table, negligible includes cases where the results are below the truncation limit or where the VFDRs were not modeled due to their insignificant contribution to risk.
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Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-3 MNS Unit I Fire Area Risk Summary Fire Area Description NFPA Fire Area Fire Area VFDR RAs Fire Risk Eval Fire Risk Eval Additional Risk Offset Risk Area 805 CDF LERF (Yes/No) (Yes/No)
A CDF5 A LERF5 of RAs (WL Mod)
Basis A LERF 19 Unit 1 Cable Room 4.2.4.2 9.21E-06 1.96E-06 Yes Yes 2.10E-06 6.30E-07 2.10E-06 / 6.30E-418E07 07 21 Auxiliary Building 4.2.4.2 1.56E-06 1.43E-07 Yes Yes 7.00E-08 1.40E-08 7.00E-08/1.40E-08 3.00E-09 Common El 750 Unit 1 Electrical 22 Penetration Room 4.2.4.2 9.79E-09 9.51 E-09 Yes No 0.00E+00 0.00E+00 0.00E+00/0.00E+00 0.00E+00 (MG Set) El 767 24 25 26 28 30 32 DIS ITS SRV SSF TB1 Control Room Common Auxiliary Building Common El 767 Unit 1 Fuel Pool Building Unit 1 Interior Doghouse Unit 1 Exterior Doghouse Unit 1 Reactor Building Discharge Structure Intake Structure Service Building Standby Shutdown Facility Unit 1 Turbine Building 4.2.4.2 3.25E-06 4.24E-07 Yes Yes 1.48E-06 2.46E-07 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 9.92E-07 6.58E-10 1.73E-07 6.19E-09 1.52E-07 2.13E-08 4.28E-08 1.15E-06 5.24E-09 7.27E-06 1.53E-07 6.39E-10 8.94E-09 4.82E-10 4.79E-08 1.54E-08 3.11 E-08 1.20E-07 3.47E-09 7.52E-07 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No 0.00E+00 0.OOE+00 0.00E+00 1.95E-09 2.50E-08 0.00E+00 0.OOE+00 0.00E+00 0.OOE+00 0.00E+00 0.OOE+00 0.00E+00 0.00E+00 9.70E-1 1 4.90E-09 0.OOE+00 0.00E+00 0.00E+00 0.OOE+00 0.00E+00 1.48E-06/2.46E-07 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 9.60E-08 0.00E+00 0.00E+00 7.00E-1 1 1.00E-12 1.20E-09 0.00E+00 0.00E+00 5.90E-08 7.00E-1 1 6.18E-07 YRD Yard Area 4.2.3.2 7.56E-08 7.31 E-08 No N/A 0.00E+00 0.00E+00 N/A 0.00E+00 Rev 0 Page W-29
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Fire Area Fire Area Description NFPA Area 805 Basis Total Fire Area CDF 3.68E-05 Table W-3 MNS Unit 1 Fire Area Risk Summary Fire Area VFDR RAs Fire Risk Eval Fire Risk Eval Additional Risk Offset Risk LERF (Yes/No) (Yes/No)
A CDF5 A LERF5 of RAs (WL Mod)
A LERF 4.86E-06 6.83E-06 1.06E-06 1.44E-06 Rev 0 Page W-30 Rev 0 Page W-30
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-4 MNS Unit 2 Fire Area Risk Summary Fire Area Description NFPA Fire Area Fire Area VFDR RAs Fire Risk Eval Fire Risk Eval Additional Risk Offset Risk Area 805 CDF LERF (Yes/No) (Yes/NO)
A CDF6 A LERF 6 of RAs (WL mod)
Basis A LERF 1
3 3A 4
7 8
Auxiliary Building Common El 695 Unit 2 Motor Driven CA Pump Room Unit 2 Turbine Driven CA Pump Room Auxiliary Building Common El 716 Unit 2 Train A Diesel Generator Room Unit 2 Train B Diesel Generator Room 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 2.16E-09 1.14E-06 3.95E-07 1.40E-07 4.91 E-08 3.44E-08 2.01 E-09 4.OOE-08 9.02E-09 8.60E-09 1.74E-08 1.55E-08 Yes Yes Yes Yes Yes Yes No No No Yes No No 2.16E-09 6.OOE-08 8.70E-08 0.OOE+00 0.OOE+00 0.OOE+00 2.01 E-09 1.90E-09 1.58E-09 0.OOE+00 0.OOE+00 0.OOE+00 N/A N/A N/A 0.OOE+00/0.OOE+00 N/A N/A 0.00E+00 2.OOE-10 8.OOE-1 1 1.OOE-1 1 2.10E-09 2.1OE-09 Unit 2 Train B 10-12 Electrical Penetration 4.2.4.2 1.62E-06 6.85E-08 Yes No 6.OOE-08 1.40E-09 N/A 1.04E-08
& Switchgear Rooms 13 Battery Rooms 4.2.4.2 4.90E-06 4.23E-07 Yes Yes 8.30E-07 1.65E-07 8.30E-07/1.65E-07 6.20E-08 Common 14 Auxiliary Building 4.2.4.2 1.87E-06 1.91 E-07 Yes Yes 1.13E-06 1.56E-07 1.13E-06/1.56E-07 3.OOE-09 Common El 733 Unit 2 Train A 16-18 Electrical Penetration 4.2.4.2 9.48E-06 3.91 E-07 Yes No 8.60E-07 3.90E-08 N/A 1.33E-07
& Switchgear Rooms 6 When used in the context of delta risk, O.OOE+00 is defined as negligible. For this table, negligible includes cases where the results are below the truncation limit or where the VFDRs were not modeled due to their insignificant contribution to risk.
Rev 0 Page W-31
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights Table W-4 MNS Unit 2 Fire Area Risk Summary Fire Area Description NFPA Fire Area Fire Area VFDR RAs Fire Risk Eval Fire Risk Eval Additional Risk Offset Risk Area 805 CDF LERF (Yes/No) (Yes/NO)
A CDF 6 A LERF6 of RAs (WL mod)
Basis A LERF Unit 2 Train A 18A Switchgear HVAC 4.2.4.2 1.47E-07 9.31 E-09 Yes No 1.47E-07 9.31 E-09 N/A 2.19E-09 Room 20 Unit 2 Cable Room 4.2.4.2 1.61 E-05 1.89E-06 Yes Yes 1.90E-06 2.40E-07 190 I 2.40E-3.64E-06 07 21 Auxiliary Building 4.2.4.2 1.12E-06 5.06E-08 Yes Yes 1.00E-08 6.00E-10 1.00E-08/6.00E-10 3.10E-09 Common El 750 Unit 2 Electrical 23 Penetration Room 4.2.4.2 9.71 E-09 9.41 E-09 Yes No 0.00E+00 0.00E+00 N/A 0.00E+00 (MG Set) El 767 24 25 27 29 31 33 DIS ITS SRV SSF TB2 Control Room Common Auxiliary Building Common El 767 Unit 2 Fuel Pool Building Unit 2 Interior Doghouse Unit 2 Exterior Doghouse Unit 2 Reactor Building Discharge Structure Intake Structure Service Building Standby Shutdown Facility Unit 2 Turbine Building 4.2.4.2 3.38E-06 5.10E-07 Yes Yes 1.47E-06 2.98E-07 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 4.2.4.2 8.64E-07 6.05E-10 3.73E-07 6.16E-09 6.89E-08 2.12E-08 4.28E-08 4.30E-07 5.24E-09 5.92E-06 1.98E-07 5.89E-10 1.68E-08 4.80E-1 0 4.03E-08 1.54E-08 3.11E-08 4.36E-08 3.47E-09 6.27E-07 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No No No 0.00E+00 0.00E+00 0.OOE+00 1.93E-09 2.85E-08 0.00E+00 0.00E+00 0.OOE+00 0.OOE+00 0.00E+00 0.OOE+00 0.OOE+00 0.00E+00 9.60E-1 1 1.74E-08 0.00E+00 0.00E+00 0.OOE+00 0.00E+00 0.OOE+00 1.47E-06/2.98E-07 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 1.15E-07 0.OOE+00 0.OOE+00 1.00E-10 1.OOE-12 0.OOE+00 0.00E+00 0.00E+00 3.1OE-08 7.OOE-1 1 5.02E-07 Rev 0 Page W-32 Rev 0 Page W-32
Duke Energy Carolinas, LLC Attachment W - Fire PRA Insights I
Table W-4 MNS Unit 2 Fire Area Risk Summary Fire Area Description NFPA Fire Area Fire Area VFDR RAs Fire Risk Eval Fire Risk Eval Additional Risk Offset Risk Area 805 CDF LERF (Yes/No) (Yes/NO)
A CDF6 A LERF6 of RAs (WL mod)
Basis A LERF YRD Yard Area 4.2.3.2 7.56E-08 7.31 E-08 No N/A O.OOE+00 O.OOE+00 N/A O.OOE+00 Total 4.82E-05 4.69E-06 6.59E-06 9.32E-07 4.51 E-06 Rev 0 Page W-33 Rev 0 Page W-33