ML25167A205

Slides for Proposed Limerick ILRT LAR Preapplication Meeting

ML25167A205
Person / Time
Site:	Limerick
Issue date:	06/26/2025
From:	Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation
Davis, R
References
Download: ML25167A205 (1)

Text

Limerick One-Time Extension of Type A (ILRT) LAR June 26, 2025

• Introductions

• Meeting Objectives

• Background Information

• Scope of Technical Specification Changes

• Justification

• Review of Proposed LAR Submittal

• Overview of Submittal Schedule

• Summary and Wrap-up

• Questions Agenda 1

Limerick One-Time Extension of Type A (ILRT) LAR

Corporate Licensing Engineers - Ronnie Reynolds, Lane Oberembt Corporate Licensing Senior Manager - Wendi Para Corporate/Limerick Risk Engineer - Connelly Richards Limerick Regulatory Assurance Manager - Jordan Rajan Limerick Regulatory Assurance Engineers - George Budock, Renee Guy Corporate Engineering - Brian Mast, Mark Weis Limerick Appendix J Engineering - Evan Dimmerling Limerick Coatings Engineer - Lorrha Hitchner Limerick Digital Modernization Project Team Members - Brian Devine, Steve Hesse, Scott Schumacher, Brian Wysowski

Introductions

2 Limerick One-Time Extension of Type A (ILRT) LAR

• Present information to the NRC to provide a clear understanding of the proposed Limerick License Amendment Request (LAR)

- One-time extension to Technical Specification (TS) 6.8.4.g Primary Containment Leakage Rate Testing Program and corresponding extension of TS 4.6.2.1.e Drywell-to-Suppression Chamber Bypass Leak Test (DWBT)

• Justify how the extension supports the safe and efficient installation of the Digital Modernization Project (DMP) during a non-typical refueling outage.

• Obtain feedback from the NRC on the proposed LAR to ensure a high-quality submittal and support efficient use of resources, both NRC & Constellation.

• Establish a mutual understanding of the proposed schedule and corresponding need date to ensure adequate NRC resource availability Meeting Objectives 3

Limerick One-Time Extension of Type A (ILRT) LAR

• The LGS Digital Modernization Project 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 system (EOC-RPT) instrumentation with a new single digital control system.

• Limerick Digital Modernization Project is currently scheduled for implementation during the spring of 2026 and 2027 (Li1R21 & Li2R19, respectively).

Background Information Limerick One-Time Extension of Type A (ILRT) LAR 4

• TS 3/4.6.1.2 requires the overall integrated leakage rate test Type A to be performed in accordance with the Primary Containment Leakage Rate Testing Program, described in TS 6.8.4.g.

• TS 3/4.6.2.1.e requires the drywell-to-suppression chamber bypass leak test to coincide with the Type A test.

• TS 6.8.4.g requires the Primary Containment Leakage Rate Testing Program to be in accordance with NEI 94-01, Rev. 3-A, dated July 2012, and the Limitations and Conditions specified in NEI 94-01, Rev. 2-A, dated October 2008.

• Limerick TS Amendments 241/204 (U1/U2) extended the interval between Type A tests from 10 years to 15 years and updated the associated references.

- The U1 ILRT last performed in March 2012 and due March 2027; scheduled April 2026 (Li1R21).

- The U2 ILRT last performed in April 2013 and due April 2028; scheduled April 2027 (Li2R19).

Background Information cont.

5 Limerick One-Time Extension of Type A (ILRT) LAR

• The LAR for a one-time extension to TS 6.8.4.g is proposing a change to Limerick TS 6.8.4.g to extend the performance of the next Type A test to no later than April 2028 for Unit 1 (13-month extension) and April 2029 for Unit 2 (12-month extension).

- This would also extend the drywell-to-suppression chamber bypass leak test since this test is performed with the Type A test.

• In addition, the proposed change would allow the Type A test to be extended indefinitely if the test interval ends while primary containment integrity is not required (i.e., TS 3.6.1, "Primary Containment," does not require the primary containment to be operable in Modes 4 and 5). In this case, the Type A test would be performed prior to entering Mode 2.

• The proposed change would also administratively update the impacted TS Sections with minor formatting changes to align Unit 1 and Unit 2 TS requirements.

Scope of Technical Specification Changes 6

Limerick One-Time Extension of Type A (ILRT) LAR

• The DMP will be the largest analog to digital upgrade of the safety-related Plant Protection Systems (PPS) at an operating nuclear plant.

- ~ 1800 safety-related components being replaced by software functionalities.

- ~ 3000 procedure changes (operational, maintenance, IST, etc.) required

• In support of extensive work planned, LGS requested and received NRC approval to disable the Redundant Reactivity Control Systems (RRCS) 30 days prior to start of DMP outage (ML24151A384).

Justification Limerick One-Time Extension of Type A (ILRT) LAR 7

• Following DMP installation, the site will perform the Modification Acceptance Test (MAT):

- ~ 500 iterations of plant line-ups, logic tests, pump starts, valve strokes, etc. to justify PPS operability.

- The MAT will be performed in Modes 4 & 5

• ILRT also requires revision because of changes to components that are being modified by the DMP and would be performed in Mode 5.

Justification cont.

Limerick One-Time Extension of Type A (ILRT) LAR 8

• Independent risk assessment determined that increasing the interval between ILRTs from 15 to 16.25 years resulted in a risk increase that fell well below the very small risk change as defined in RG 1.174.

• Prior performance of Type A (ILRT) tests have confirmed that the containment is acceptable with considerable margin to the TS acceptance criteria.

• Type B and Type C tests (part of the Primary Containment Leakage Rate Program but not being modified with this LAR) have also demonstrated acceptable results.

• Various Containment Inspection Programs including the Protective Coatings Program (both Drywell and Suppression Pool) and In-Service Inspection Programs (Liner, Concrete, Penetrations) have shown continuing acceptable results.

• No modifications requiring a post-maintenance verification Type A test are planned prior to the Spring 2028 (U1) and Spring 2029 (U2) refueling outages.

Justification cont.

Limerick One-Time Extension of Type A (ILRT) LAR 9

Unit 1 Unit 2 Limerick One-Time Extension of Type A (ILRT) LAR 10 Review of Proposed LAR Submittal

• Pre-submittal Meeting with NRC to Discuss LAR - June 26, 2025

• LAR submittal by CEG by early July 2025

• Request NRC approval by March 31, 2026, to support implementation of the Digital Modernization Project changes in Li1R21 (spring 2026) and Li2R19 (spring 2027).

• Performance of the next ILRT Type A test in Li1R22 (spring 2028) and Li2R20 (spring 2029).

Overview of Submittal Schedule 11 Limerick One-Time Extension of Type A (ILRT) LAR

• Extend Type A (ILRT) interval by 13 months for Unit 1 and 12 months for Unit 2 to allow Limerick to focus on the safe and efficient installation of the Digital Modernization Project.

• Performance of the Type A tests during the refueling outages in Li1R22 (spring 2028) and Li2R20 (spring 2029).

• Continue to perform other scheduled inspections in support of Primary Containment Leakage Rate Testing Program as planned during upcoming refueling outages.

Summary and Wrap-up 12 Limerick One-Time Extension of Type A (ILRT) LAR

Questions?

Limerick One-Time Extension of Type A (ILRT) LAR 13

Supplemental Information Limerick One-Time Extension of Type A (ILRT) LAR 14

LCO 3.6.1.2 SR 3/4.6.2.1.e Supplemental Information 15 Limerick One-Time Extension of Type A (ILRT) LAR

TS 6.8.4.g Supplemental Information cont.

16 Limerick One-Time Extension of Type A (ILRT) LAR