ML23143A342

Supplement to License Amendment Request to Revise the Licensing and Design Basis to Incorporate the Replacement of Existing Safety-Related Analog Control Systems with a Single Digital Plant Protection System

ML23143A342
Person / Time
Site:	Limerick
Issue date:	05/23/2023
From:	David Helker Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
Download: ML23143A342 (1)

Text

200 Exelon Way Kennett Square, PA 19348 Constellation~ www.ConstellationEnerqy.com

10 CFR 50.90

May 23, 2023

U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTN: Document Control Desk

Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

Subject:

Supplement to License Amendment Request to Revise the Licensing and Design Basis to Incorporate the Replacement of Existing Safety-Related Analog Control Systems with a Single Digital Plant Protection System (PPS) -

Pivot to Unit 2 First Installation

References:

1. Constellation Energy Generation, LLC (CEG) letter to the U.S. Nuclear Regulatory Commission (NRC), "License Amendment Request to Revise the Licensing and Design Basis to Incorporate the Replacement of Existing Safety-Related Analog Control Systems with a Single Digital Plant Protection System (PPS)," dated September 26, 2022 (NRC Agencywide Documents Access and Management System (ADAMS) Accession No.

ML22269A5690).

2. U.S. Nuclear Regulatory Commission (NRC) letter to Constellation Energy Generation, LLC (CEG), "Limerick Generation Station, Unit Nos. 1 and 2 -

Acceptance of Requested Licensing Action Re: Replacement of Existing Safety Related Analog Control Systems with a Single Digital Plant Protection System (EPID L-2022-LLA-0140)," dated December 9, 2022 (ADAMS Accession No. ML22339A064).

3. Constellation Energy Generation, LLC (CEG) letter to the NRC, "License Amendment Request to Revise Technical Specifications and Exemption Request from Requirements of 1 0CFR50.62 A TWS Rule to Support the Digital Modernization Project Installation," dated February 17, 2023 (ADAMS Accession No. ML23048A313).

Per Reference 1 and in accordance with 10 CFR 50.90, Constellation Energy Generation, LLC (CEG) requested amendments to Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively. The proposed changes would revise the LGS licensing and design basis to incorporate a planned digital modification at LGS (i.e., the LGS Digital Modernization Project).

Supplement to License Amendment Request Limerick Digital Modernization Project Docket Nos. 50-352 and 50-353 May 23, 2023 Page 2

The LGS Digital Modernization Project (DMP) will replace the existing analog control logic hardware of the Reactor Protection System (RPS) instrumentation, Nuclear Steam Supply Shutoff System (NSSSS) instrumentation, the Emergency Core Cooling System (ECCS) instrumentation, the Reactor Core Isolation Cooling (RCIC) System instrumentation, and the End-of-Cycle Recirculation Pump Trip (EOC-RPT) instrumentation with a new, single, digital control system. The new, single, digital control system (i.e., for RPS, NSSSS, ECCS, RCIC, and EOC-RPT) will be renamed the Plant Protection System (PPS).

In Reference 1, CEG communicated plans to implement the LGS DMP during the LGS Unit 1 20th refueling outage (Li1 R20) and LGS Unit 2 18th refueling outage (Li2R 18), currently scheduled to commence in April 2024 and April 2025, respectively. CEG requested approval of the proposed license amendments by March 1, 2024 (i.e., 15 months following a two-month acceptance review). The proposed TS changes would be implemented prior to start-up from the Li 1 R20 and Li2R 18 refueling outages.

In Reference 2, NRC provided their acceptance of the license amendment request (LAR) for further NRC review. Based on the information provided in the LAR, including the schedule for when supplemental information would be provided, the NRC staff estimated that this LAR would take approximately 7000 hours0.081 days <br />1.944 hours <br />0.0116 weeks <br />0.00266 months <br /> to complete. The NRC staff expected to complete this review by March 11, 2024. That completion date would have supported installation of the new PPS during the Unit 1 2024 Refuel Outage starting in April 2024.

Subsequent to the LAR NRC Acceptance Review, the final design activities for the PPS have been delayed due to additional design refinement iterations with the system Original Equipment Manufacturer. CEG has concluded that it is no longer possible to have the design completed and equipment ready in time to support the Unit 1 installation during the April 2024 Refuel Outage. Therefore, CEG is pivoting final design and project activities to support the first installation of the PPS on Unit 2 during its planned April 2025 Refuel Outage.

During the Acceptance Review Process, CEG indicated that the following documents associated with the LAR would be submitted on the specified dates. An update to that schedule follows and additional LAR supplements are identified in the table below.

DMP LAR Supplemental Information Date of Planned Submittal

APP-GW-GLR-611, Rev. 3, "ITAAC 2.5.02.14: Component Interface July 31, 2023 Module Desian Process Technical Report" WCAP-16097-P Appendix 5, Revision 6, "Common Qualified Platform" July 31, 2023

D-3 Coping Analysis (Revision 3) Submittal July 31, 2023

VOP Summary (Revision 1) Submittal July 31, 2023

SyRS (Revision 2) Submittal August 31, 2023 Supplement to License Amendment Request Limerick Digital Modernization Project Docket Nos. 50-352 and 50-353 May 23, 2023 Page 3

SyDS (Revision 4) Submittal August 31, 2023

FMEA (Revision 1) Submittal August 31, 2023

LAR Attachment 1 (Revision 1) Submittal August 31, 2023

L TR (Revision 1) Submittal September 15, 2023

Seismic Equipment Qualification Summary Report, Revision 0 November 22, 2023 Environmental Equipment Qualification Summary Report, Revision 1 January 24, 2024

Electromagnetic Compatibility Equipment Qualification Summary January 24, 2024 Report, Revision 2

Note for the SyRS and SyDS revisions, we will evaluate whether the changes are significant enough to affect the LAR, and if so, will plan to submit them in the late August 2023 time frame. The L TR planned submittal date assumes the LAR Audit Open Item Process regarding L TR concerns will be mostly completed near the proposed submittal date.

In addition, the DMP Installation Support LAR (Reference 3) will need to be supplemented because the original refueling outage dates are embedded in the proposed Unit 1 Technical Specification Markups and will need to be updated to reflect the new outage installation schedule. This supplement is expected to be submitted by July 31, 2023.

CEG now plans to implement the LGS DMP during the LGS Unit 2 refueling outage (Li2R18) and LGS Unit 1 refueling outage (Li1 R21 ), currently scheduled to commence in April 2025 and April 2026, respectively. CEG understands that the original NRC review timeline presented during the Acceptance Review will need to be modified. CEG respectfully requests approval of the proposed license amendments as soon as possible after the original March 11, 2024 date. We also request that the NRC inform us of the impact to the original NRC review time and cost estimates associated with the project moving the first installation to Unit 2 in April 2025.

This supplemental letter contains no regulatory commitments.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (b), CEG is notifying the Commonwealth of Pennsylvania of this LAR supplemental letter by transmitting a copy of this letter to the designated State Official.

If you have any questions regarding this submittal, please contact Frank Mascitelli at Frank. Mascitelli@constellation.com.

Supplement to License Amendment Request Limerick Digital Modernization Project Docket Nos. 50-352 and 50-353 May 23, 2023 Page 4

I declare under penalty of perjury that the foregoing is true and correct. Executed on this 23 rd day of May 2023.

Respectfully,

David P. Helker Sr. Manager - Licensing Constellation Energy Generation, LLC

cc: USNRC Region I, Regional Administrator II USNRC Project Manager, LGS USNRC Senior Resident Inspector, LGS "

II Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection