ML22325A314
| ML22325A314 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 11/30/2022 |
| From: | Duke Energy Carolinas |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| EPID L-2022-LRM-0084 | |
| Download: ML22325A314 (1) | |
Text
McGuire/NRC Pre-submittal Meeting:
LAR to Adopt TSTF-505, Rev. 2 (Risk-Informed Completion Times)
LAR to Adopt 10 CFR 50.69 November 30, 2022
Duke Energy Attendees Ryan Treadway (Director, Nuclear Fleet Licensing)
Bob Rishel (Director, Probabilistic Risk Assessment)
Heather Szews (Manager, Probabilistic Risk Assessment)
Jordan Vaughan (Lead Nuclear Engineer, Nuclear Fleet Licensing)
Art Mironenko (Senior Nuclear Engineer, Probabilistic Risk Assessment)
Jennifer Varnedoe (Lead Nuclear Engineer, Probabilistic Risk Assessment)
Ryan Severns (Assistant Operations Manager - Shift, McGuire Operations)
John Banse (Shift Manager - McGuire Operations) 2 2
Agenda TSTF-505 Introduction (Desired Meeting Outcomes)
PRA Models and Real-Time Risk Model Overview License Amendment Request Overview Recent OE (TSTF-505 LARs and associated audits)
Implementation Timeline for LAR Submittal 10 CFR 50.69 License Amendment Request Overview Timeline for LAR Submittal 3
Overview of PRA Portion of MNS TSTF-505 LAR 4
4 Consistent with TSTF-505 Rev. 2 Template No Loss of Function TS Actions are proposed PRA models updated/upgraded and peer-reviewed F&O Closure independently validated Total CDF/LERF meet RG 1.174 criteria Seismic: Penalty applied for CDF and LERF High Winds: LOOPs included in IE PRA HW penalty applied for CDF and LERF for select LCOs above screening threshold Submit LAR with option of using High Winds PRA in the future External Flooding: Hazard screened per the standard Unit-specific PRAs will be used for application Sample calculations presented in LAR are from Unit 1, consistent with other applications
Internal Events PRA 5
5 2015 - MNS IE PRA model was subject to a full-scope peer review against RG 1.200 Rev. 2 IAW guidance in NEI 05-04.
Findings were reviewed and closed in Feb 2016, May 2019 and Nov 2021 for the IE PRA model using the process documented in Appendix X to NEI 05-04, NEI 07-12 and NEI 12-13, Close-out of Facts and Observations (F&Os) as accepted by NRC (ML17079A427).
There are zero open findings and all applicable supporting requirements are met at capability category II.
Internal Flood PRA 6
6 2011 - MNS IF PRA model was subject to a full-scope peer review against RG 1.200 Rev. 2 IAW guidance in NEI 05-04.
Findings were reviewed and closed in Sep 2015, Dec 2018 and Sep 2022 for the IE PRA model using the process documented in Appendix X to NEI 05-04, NEI 07-12 and NEI 12-13, Close-out of Facts and Observations (F&Os) as accepted by NRC (ML17079A427).
There are zero open findings and all applicable supporting requirements are met at capability category II.
7 2014 - MNS HW PRA model was subject to a full-scope peer review against RG 1.200 Rev. 2 IAW guidance in NEI 05-04.
Findings were reviewed and closed in November 2021 for the HW PRA model using the process documented in Appendix X to NEI 05-04, NEI 07-12 and NEI 12-13, Close-out of Facts and Observations (F&Os) as accepted by NRC (ML17079A427).
There are zero open findings and all applicable supporting requirements are met at capability category II.
Fire PRA 8
8 2009 - MNS Fire PRA was subject to full-scope peer review against RG 1.200 Rev. 2 IAW guidance in NEI 07-12.
Focused scope industry peer reviews were conducted against RG 1.200 Rev. 2 related to an identified upgrades in Aug 2018, Nov 2020, Nov 2021, and Aug 2022.
Findings were reviewed and closed in Aug 2018, Nov 2020, Nov 2021 and August 2022 for the Fire PRA models using the process documented in Appendix X to NEI 05-04, NEI 07-12 and NEI 12-13, Close-out of Facts and Observations (F&Os) as accepted by NRC (ML17079A427).
There are zero open findings and all applicable supporting requirements are met at capability category II.
F&O Closure Review 9
9 Formal process by independent review team Assessed disposition of Findings for Internal Events, Internal Flooding, High Winds and Fire PRAs Addressed in detail in the LAR assessment Technical Adequacy section The process evaluated whether the disposition of each finding constitutes an update or upgrade
Other Hazards 10 10 Seismic The baseline and delta Seismic CDF (SCDF) is based on the Plant Level Fragility (PLF).
The baseline Seismic LERF (SLERF) is based on the realistic LERF fragility while the delta SLERF is based on the conservatively biased Review Level Earthquake (RLE).
Improved seismic penalty will be applied to all RICTs by eliminating two unrealistic conservatisms:
There is no configuration risk for seismic hazard bins with the Plant Level Fragility (PLF) or Conditional Core Damage Probability (CCDP) of 1.
The possible maximum configuration or delta risk for hazard bins with the PLF or CCDP close to one is limited by 1 - CCDP.
Unrealistic Conservatism 1 CCDP is one for %G7 to %G10. As such, there is no CCDP for the sake of RICT calculation.
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Unrealistic Conservatism 2 CCDP is already high, close to one. As such, the possible maximum CCDP should be limited to 1 - CCDP for the sake of RICT calculation.
Other Hazards 13 13 High Winds High Winds LOOPs included in IE PRA High Winds penalty will be applied to select LCOs where configuration specific RICTs were above the screening threshold Hurricane, Straight-line winds and Tornado high wind hazard screened for other RICTs below the screening threshold Submit with option to use the High Winds PRA for RICT program in future, instead of penalty
Other Hazards (continued)
External Flooding External Flooding hazard can be screened from calculations in the RICT Program.
Other Hazards No other external hazards required to be included in the RICT calculations.
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RICT Program Real-Time Risk Model 15 15 Real-Time Risk Model as currently used for existing Maintenance Rule a(4)
Configuration Risk Management Program Uses PHOENIX Risk Analysis Software Incorporates RICT/RMAT calculation features
License Amendment Request Based on TSTF-505, Revision 2 and NEI 06-09 19 different Technical Specifications (TS) impacted by proposed change Various instrumentation TS are proposed to be in scope of RICT Program Modes 1 and 2 only for RICT Program New TS Section 5 Program for RICT Program Variations from TSTF-505, Revision 2 Subtle differences in Condition/Required Action wording TSTF-505 Conditions/LCOs exist that are not in the MNS TS Re-typed/clean TS pages not included RICTs proposed for some plant-specific TS Actions not in TSTF-505, Rev. 2 16 16
TS 3.3.1, Reactor Trip System (RTS) Instrumentation Function 10.a and associated Condition O (re-numbered) is plant-specific and thus is not in NUREG-1431/TSTF-505, Rev. 2 Condition O (re-numbered) applies to one Reactor Coolant Flow - Low (Single Loop) inoperable.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed to place the inoperable channel in trip Conservatively models one generic 2/3 logic input (per train) which feeds into SSPS 17 17
TS 3.3.2, ESFAS Instrumentation NUREG-1431, and therefore TSTF-505, Revision 2, does not contain an ESFAS instrumentation function for Feedwater Isolation - Tavg-Low Coincident with Reactor Trip Condition J applies to one channel of the Tavg-Low feedwater isolation function inoperable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed to place the inoperable channel in trip Function is not explicitly modeled in the PRA; a surrogate is used for failure of Auxiliary Feedwater 18 18
TS 3.4.11, Pressurizer PORVs Overview of system design Train A: one PORV and an associated block valve Train B: two PORVs, each with an associated block valve Condition J, which applies to one Train B PORV and the other Train B block valve (i.e., block valve associated with the Train B PORV remaining operable) inoperable, is a plant-specific Condition not in the NUREG-1431 STS or TSTF-505, Rev. 2 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed to restore either the PORV or block valve to operable status No loss of function with Train A operable SSCs explicitly modeled in the PRA 19 19
TS 3.8.1, AC Sources - Operating The LCO for TS 3.8.1 contains a part c. that states:
The qualified circuit(s) between the offsite transmission network and the opposite units Onsite Essential Auxiliary Power System necessary to supply power to the Nuclear Service Water System (NSWS), Control Room Area Ventilation System (CRAVS), Control Room Area Chilled Water System (CRACWS) and Auxiliary Building Filtered Ventilation Exhaust System (ABFVES)
Condition C (One LCO 3.8.1.c offsite circuit inoperable.) and Condition E (Two LCO 3.8.1.a offsite circuits inoperable. OR One LCO 3.8.1.a offsite circuit that provides power to the NSWS, CRAVS, CRACWS and ABFVES inoperable and one LCO 3.8.1.c offsite circuit inoperable. OR Two LCO 3.8.1.c offsite circuits inoperable.) are plant-specific and account for the fact that McGuire is a dual unit plant and that the opposite unit AC sources have the capability to supply shared systems.
Like the LCO 3.8.1.a offsite circuits (i.e., the unit-specific offsite circuits), the LCO 3.8.1.c offsite circuits are explicitly modeled in the PRA.
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Recent OE Key issues from other TSTF-505 audits:
Potential loss of function Conditions - none for McGuire Defense-in-depth principles associated with instrumentation TS Treatment/Credit for FLEX in the PRA Models
OE from Harris/Brunswick TSTF-505 LAR/RAI Responses and other industry TSTF-505 LAR OE 21
Implementation 22 22 Operations owns implementation Cross-functional team supporting implementation RICT implemented in Modes 1 and 2 only Real-Time Risk and PRA Models updated to support the RICT Program Procedure changes and training Industry OE (Benchmark, Risk-Informed TS Task Force, TSTF)
Procedures and Training 23 23 Existing fleet RICT Program procedures and revised site-specific procedures will address the following:
The new McGuire RICT Program (responsibilities, definitions, plant conditions for which the program applies etc.)
Calculation of risk management action times (RMAs) and RICTs Development and implementation of RMAs Use of the CRMP software tool (i.e., PHOENIX or the real-time risk model) with the RICT Program Three levels of training for the RICT Program is proposed:
Level 1 - User Training Level 2 - Management Training Level 3 - Site Awareness Training
Timeline for LAR Submittal 24 24 Next Steps:
Target submittal of LAR by end of January 2023 Revise site-specific implementing procedures in parallel and subsequent to NRC staff review of LAR; leverage existing fleet procedures that were developed and being utilized for the Harris and Brunswick RICT Programs Conduct training for RICT Program Ready to implement RICT Program within 180 days of receipt of SE
10 CFR 50.69 License Amendment Request Overview Internal Events (including Internal Flood) and Fire Same models as TSTF-505 External Hazards HW screened using existing PRA Seismic EPRI Tier 2 Alternate Passive Method Timeline for LAR submittal Close to TSTF-505 submittal so that reviewer synergies can be applied 25
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