ML25014A014
| ML25014A014 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 01/16/2025 |
| From: | Duke Energy Carolinas |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| L-2024-LRM-0147 | |
| Download: ML25014A014 (22) | |
Text
Duke Energy Pre-Submittal Meeting January 16, 2025
Pre-Submittal Meeting Strategy for the Sequencing of Proposed License Amendment Requests to Facilitate the Utilization of AXIOM Fuel Rod Cladding Catawba Nuclear Station (CNS)
McGuire Nuclear Station (MNS) 2
Duke Energy Attendees Ryan Treadway (Director, Nuclear Fleet Licensing)
Dennis Earp (Lead Nuclear Engineer, Licensing)
Roger Thomas (Manager, Fuel Mechanical Performance)
Charles Stroupe (Manager, Safety Analysis Applications)
Jeff Abbott (Manager, Safety Analysis Models)
Geoff Pihl (Manager, Nuclear Fuels Engineering - PUMA)
Mark Handrick (Principal Nuclear Engineer - Safety Analysis Applications)
Stan Hayes (Principal Nuclear Engineer - Fuel Mechanical Performance) 3 3
Agenda
Background
Proposed Strategy Reason for Proposed Changes Proposed Technical Specification (TS) Changes LAR 1: Reactor Core Safety Limit Revision LAR 2: AXIOM and FSLOCA TR Adoption Milestones/Schedule Regulatory Requirements and Guidance 4
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Background===
First pre-submittal meeting was conducted on October 28, 2024 (ADAMS Accession No. ML24302A070).
Proposed submittal of a singular license amendment request (LAR) to cover the adoption of Westinghouse Topical Report (TR) WCAP-18546-P/NP, Westinghouse AXIOM Cladding for Use in Pressurized Water Reactor Fuel, Westinghouse TR WCAP-16996-P-A, Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FULL SPECTRUM LOCA Methodology (FSLOCA)), and the peak fuel centerline temperature specified in Westinghouse TR WCAP-17642-P/NP, Westinghouse Performance Analysis and Design Model (PAD5).
Supporting FSLOCA analysis to be complete in July 2025.
Composite bounding analysis for CNS Unit 1 and MNS Units 1 and 2 CNS Unit 2 will have a separate FSLOCA analysis to be covered by a separate submittal All three TRs are necessary to support utilization of AXIOM-clad fuel by CNS and MNS First reload starting April 2026 with CNS Unit 1 5
Proposed Strategy Multi-LAR strategy to support adoption of necessary Topical Reports and limits to support utilization of AXIOM-clad fuel
LAR 1 - Revise Reactor Core Safety Limit 2.1.1.2 to Reflect Peak Fuel Centerline Temperature from PAD5 TR
Applicable to CNS Units 1 and 2 and MNS Units 1 and 2
Submittal in February 2025
LAR 2 - Adoption of AXIOM TR and FSLOCA Methodology TR
Applicable to CNS Unit 1 and MNS Units 1 and 2
Revises TS 4.2.1, Fuel Assemblies, to add AXIOM as a fuel assembly cladding material and delete reference to Zircalloy
Revises TS 5.6.5, Core Operating Limits Report (COLR), to include the FULL SPECTRUMTM Loss-of-Coolant Accident (FSLOCATM) Evaluation Model (EM) and the Topical Report for AXIOMTM and clean up the current list of approved analytical methods used to determine the core operating limits
Includes 10 CFR 50.12 Exemption Request addressing AXIOM and 10 CFR 50.46 requirements
Submittal in August 2025 A third LAR will focus on CNS Unit 2 adoption of the AXIOM TR and FSLOCA Methodology TR separately to support implementation in Spring 2027.
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Reason for Proposed Changes CNS and MNS will begin utilizing AXIOM cladding instead of Optimized ZIRLO cladding for feed batches starting with CNS Unit 1 in Spring 2026.
This will support a full core of AXIOM cladding during the initial 24 month or power uprate cycles at CNS and MNS.
AXIOM provides additional hydrogen pickup margin relative to Optimized ZIRLO, which aids corrosion analysis margin management for the transition to 24 month and/or power uprate core designs.
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Proposed Technical Specification (TS) Changes 8
Proposed Technical Specification (TS) Changes 9
Proposed Technical Specification (TS) Changes 10 10 LAR 2 - CNS
Proposed Technical Specification (TS) Changes 11 11 LAR 2 - Changes to CNS/MNS Technical Specifications Section 5.6.5.b (i.e., analytical methods used to determine the core operating limits)
Delete the following two methods:
- 2. WCAP-10266-P-A, The 1981 Version of the Westinghouse Evaluation Model using the BASH Code (W Proprietary)
- 3. BAW-10168-P-A, B&W Loss-of-Coolant Accident Evaluation Model for Recirculating Steam Generator Plants (B&W Proprietary)
Add the following methods to support the analyses of AXIOM fuel with FSLOCA:
xx. WCAP-16996-P-A, Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FULL SPECTRUM LOCA Methodology) (W Proprietary) xy. WCAP-18546-P-A, Westinghouse AXIOM Cladding for Use in Pressurized Water Reactor Fuel (W Proprietary)
NOTE: CNS TS will include [Unit 1 Only - per License Amendment XXX]
Proposed Technical Specification (TS) Changes 12 12 (Continued)
Changes to CNS/MNS Technical Specifications Section 5.6.5.b (i.e., analytical methods used to determine the core operating limits)
Annotate the following methods that can be removed from the COLR methods list after all the fuel with Optimized ZIRLOTM cladding is discharged, and all fuel with AXIOMTM cladding is covered by FSLOCATM:
- 13. WCAP-10054-P-A, Westinghouse Small Break ECCS Evaluation Model using the NOTRUMP Code (W Proprietary) [Shall not be used to determine core operating limits after XYZ]
- 15. WCAP-12945-P-A, Volume 1 and Volumes 2-5, Code Qualification Document for Best-Estimate Loss of Coolant Analysis (W Proprietary) [Shall not be used to determine core operating limits after XYZ]
Where XYZ reflects the first refueling cycles corresponding to full cores of AXIOM-clad fuel.
LAR 1: Reactor Core Safety Limit Revision NRC review of Westinghouse TR WCAP-17642-P/NP, Westinghouse Performance Analysis and Design Model (PAD5), found it acceptable for referencing in licensing applications to the extent specified and under the limitations and conditions delineated in the NRC staffs Safety Evaluation (SE) [ADAMS Accession No. ML17090A443].
PAD5 supports advanced fuel designs and analysis methods o AXIOM cladding is modeled with PAD5 NRC SE also concluded that the fuel melting limits in PAD5 are acceptable.
Ability to utilize PAD5 by CNS/MNS requires updating TS SL 2.1.1.2 to reflect the updated burnup-dependent term of the fuel melting limits provided in the PAD5 code.
CNS/MNS will meet the pertinent constraints identified as Limitations and Conditions by:
Application of PAD5 within the limits specified for cladding, fuel and reactor parameters Limit the peak fuel centerline temperature (per this proposed amendment request) 13
14 LAR 1: Reactor Core Safety Limit Revision (Continued)
Precedent Revised Reactor Core Safety Limit 2.1.1.b peak fuel centerline temperature in accordance with WCAP-17642-P-A, Revision 1, Westinghouse Performance Analysis and Design Model (PAD5)
Millstone Power Station Unit 3 (ADAMS Accession No. ML21326A099)
Turkey Point Nuclear Generating Unit Nos. 3 and 4 (ADAMS Accession No. ML19031C891)
LAR 2: AXIOM and FSLOCA TR Adoption 15 15 AXIOM NRC review of Westinghouse TR WCAP-18546-P/NP, Westinghouse AXIOM Cladding for Use in Pressurized Water Reactor Fuel, found it acceptable for referencing in licensing applications to the extent specified and under the limitations and conditions delineated in the TR and the NRC staffs Safety Evaluation (SE) [ADAMS Accession No. ML22306A248].
PAD5 TR applicability was expanded to include AXIOM cladding material.
Implementation of AXIOM cladding is contingent on the use of PAD5; therefore, LOCA analyses are expected to be performed using the FSLOCA methodology.
CNS/MNS will meet the constraints identified as Limitations and Conditions of the AXIOM TR and corresponding NRC staff SE.
LAR 2: AXIOM and FSLOCA TR Adoption (Continued) 16 16 Limitations and Conditions in AXIOM TR and NRC SE:
Use with NRC-approved PWR design Use with NRC-approved Westinghouse and CE fuel design with corresponding pellet and assembly dimensions Use with NRC-approved fuel materials and pellet coatings or additives (e.g., ADOPT IFBA, gadolinium)
Fuel burnup currently limited to 62 GWd/MTU peak rod average for all cladding types
- Higher limit may be allowed once additional information specific to increased burnup is submitted and approved by the NRC Best Estimate Oxide Thickness < 100 µm Best Estimate HPU within limit
17 LAR 2: AXIOM and FSLOCA TR Adoption (Continued)
Precedent - AXIOM Turkey Point Nuclear Generating Unit Nos. 3 and 4 (ADAMS Accession No. ML23320A028)
[Under Review by NRC]
Proposed the incorporation of AXIOM into the licensing basis Also proposed incorporating advanced fuel features ADOPT fuel pellets and a PRIME fuel skeleton, as well as extending TS surveillance intervals, modifying TS Allowable Values and a Trip Setpoint to facilitate a transition to 24-month fuel cycles, but that is beyond the scope of the Duke Energy proposed LAR.
Included exemption request from certain requirements of 10 CFR 50.46 to support application of AXIOM cladding Note: CNS/MNS LAR only proposing the adoption of AXIOM cladding material.
LAR 2: AXIOM and FSLOCA TR Adoption (Continued)
FSLOCA NRC review of Westinghouse TR WCAP-16996-P/WCAP-16996-NP, Volumes I, II, and III, Revision 1, Realistic Loss-Of-Coolant Accident Evaluation Methodology Applied to the Full Spectrum of Break Sizes, found it acceptable for referencing in licensing applications for use of the FSLOCA evaluation methodology to perform best-estimate analyses for the entire spectrum of LOCAs including small break LOCA, intermediate break LOCA, and large break LOCA scenarios in Westinghouse designed three-and four-loop pressurized-water reactor plants with cold leg injection only provided that the limitations and conditions stipulated in the NRC final SE are met along with the proper documentation.
CNS/MNS will meet the constraints identified as Limitations and Conditions per NRC staff SE.
Duke Energy has an existing commitment to NRC to re-analyze Large Break LOCA with methods that explicitly consider fuel pellet Thermal Conductivity Degradation (TCD). The FSLOCA methodology explicitly considers TCD effects. [ADAMS Accession No. ML16271A329]
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19 LAR 2: AXIOM and FSLOCA TR Adoption (Continued)
Precedent - FSLOCA Content for the FSLOCA analysis will be similar to that provided by the following:
Watts Bar Nuclear Plant, Units 1 and 2 (ADAMS Accession No. ML21034A169)
Turkey Point Nuclear Generating Unit Nos. 3 and 4 (ADAMS Accession No. ML22028A066)
Basis for composite FSLOCA analysis for MNS/CNS:
MNS - ADAMS Accession No. ML003753895 CNS - ADAMS Accession No. ML003756631
Milestones/Schedule Date Milestone February 28, 2025 Submit LAR 1 addressing TS SL revision July 31, 2025 Receipt by Duke of FSLOCA Analysis August 29, 2025 Submit LAR 2 addressing adoption of AXIOM TR and FSLOCA Methodology TR Late October or Early November 2025 Audit of AXIOM/FSLOCA Analysis content December 2025 Completion of any associated RAI By March 31, 2026 Requested approval of both LARs April 2026 CNS Unit 1 Outage Start Date 20
Regulatory Requirements and Guidance 21 Regulations 10 CFR 50.36, Technical specifications 10 CFR 50.46, Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors 10 CFR 50 Appendix A, General Design Criteria for Nuclear Power Plants GDC 10, Reactor design GDC 35, Emergency core cooling
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