ML21071A102

Summary of the February 23, 2021, Meeting with Exelon Regarding a Future License Amendment Request Related to Implementing an Alternative Categorization Process Under the Requirements of 10 CFR 50.69

ML21071A102
Person / Time
Site:	Limerick
Issue date:	03/24/2021
From:	V Sreenivas Plant Licensing Branch 1
To:	Rhoades D Exelon Nuclear, Exelon Generation Co
Dukehart C
References
EPID L-2021-LRM-0018
Download: ML21071A102 (5)

Text

March 24, 2021 LICENSEE: Exelon Generation Company, LLC FACILITY: Limerick Generating Station, Units 1 and 2

SUMMARY

OF THE FEBRUARY 23, 2021, MEETING WITH EXELON GENERATION COMPANY, LLC REGARDING A FUTURE LICENSE AMENDMENT REQUEST RELATED TO IMPLEMENTING AN ALTERNATIVE CATEGORIZATION PROCESS UNDER THE REQUIREMENTS OF 10 CFR 50.69 On February 23, 2021, a Category 1 public teleconference meeting was held between the U.S. Nuclear Regulatory Commission (NRC) staff and the representatives of Exelon Generation Company, LLC (Exelon, the licensee). The purpose of the meeting was to discuss a future license amendment request (LAR) for Limerick Generating Station, Units 1 and 2 (Limerick) to implement an alternative categorization process under the requirements of Section 50.69 of Title 10 of the Code of Federal Regulations (10 CFR). The meeting notice dated February 1, 2021, is available in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML21034A619, and the meeting slides provided by Exelon are at ADAMS Accession No. ML21049A310. A list of attendees is provided as an enclosure to this letter.

The licensee expects to submit the proposed LAR for Limerick by the end of March 2021.

The proposed amendment would allow the use of an alternative categorization process under the requirements of 10 CFR 50.69. By letter dated July 31, 2018 (ADAMS Accession No. ML18165A162), the NRC approved Limerick to implement the requirements of 10 CFR 50.69 for the risk-informed categorization of structures, systems, and components (SSCs). The proposed amendment would modify the licensing basis by revising the license condition in Appendix C of the renewed facility operating licenses for each unit to allow the option to implement an alternate defense-in-depth categorization process, an alternate pressure boundary categorization process, and an alternate seismic tier 1 categorization process under 10 CFR 50.69 based on industry documents. Exelon intends to use Limerick as a pilot for the industry to implement the defense-in-depth and passive pressure boundary alternative categorization processes.

Regarding the alternative categorization process, the licensee stated that:

Limericks probabilitistic risk assessment (PRA) model accuracy has been previously demonstrated for 10 CFR 50.69 and TSTF-5051 applications.

1 Technical Specifications Task Force (TSTF) Traveler TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4B (ADAMS Accession No. ML18183A493)

Functions/SSCs outside scope of the PRA are not evaluated.

Does not replace the Integrated Decision-making Panel defense-in-depth evaluation.

The LAR will demonstrate:

o Robust internal events model, including internal flooding; o Robust programs for localized corrosion, flow accelerated corrosion, and erosion; and, o Protective measures for internal flooding events.

The following topical reports will be referenced and available for NRC audit:

o PWROG-20015-NP, Alternate 10 CFR 50.69 Categorization Process; o EPRI 3002015999, Enhanced Risk-Informed Categorization Methodology for Pressure Boundary Components; and, o EPRI 3002017583, Alternative Approaches for Addressing Seismic Risk in 10 CFR 50.69 Risk-Informed Categorization.

It was acknowledged during the meeting that there is existing precedent for the use of the alternate seismic tier 1 categorization process via NRC issuance of an amendment for Calvert Cliffs Nuclear Power Plant to implement the requirements of 10 CFR 50.69. The NRC suggested that Exelon ensure that the LAR explain how the seismic tier 1 categorization process is applicable to Limerick, similar to other licensee submittals such as Surry and Farley.

The licensee indicated that it did not intend to submit the supporting industry documents on the docket, but that it would be available for audit by the NRC. The NRC expressed concern about the long term public availability of industry documents following subsequent revisions.

Since Exelon is seeking to have the option to use any one or all of the alternative categorization processes, the NRC questioned whether Exelon would use one or the other (i.e., the original process or the alternative process, or would mix and match the various processes). Exelon has already categorized over 20 systems at Limerick using the original categorization processes specified in the existing license condition, and indicated it does not plan to re-categorize those systems using the alternative processes; however, going forward, Exelon would most likely use the alternative processes to categorize systems. Exelon stressed that the benefit of using the alternative processes is not necessarily better results of the categorization but rather a reduction in burden on the time and resources required to perform the categorization.

No one identified themselves as being members of the public during the meeting. Public meeting feedback forms were not received.

Please direct any inquiries to V. Sreenivas at 301-415-2597 or V.Sreenivas@nrc.gov.

/RA/

V. Sreenivas, Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353

Enclosure:

List of Attendees cc: Listserv

LIST OF ATTENDEES MEETING WITH EXELON GENERATION COMPANY, LLC REGARDING A FUTURE LICENSE AMENDMENT REQUEST RELATED TO IMPLEMENTING AN ALTERNATIVE CATEGORIZATION PROCESS UNDER THE REQUIREMENTS OF 10 CFR 50.69 AT LIMERICK GENERATING STATION, UNITS 1 AND 2 FEBRUARY 23, 2021 Name Affiliation Corey Dukehart U.S. Nuclear Regulatory Commission (NRC)

V Sreenivas NRC Ed Miller NRC Aaron Armstrong NRC Odunayo Ayegbusi NRC Jeff Circle NRC Hari Kodali NRC Chang Li NRC Charles Moulton NRC Keith Tetter NRC Ming Li NRC Alissa Neuhausen NRC Paul Prescott NRC Yuken Wong NRC David Passehl Jensen Hughes Contractors David Bidwell Jensen Hughes Contractors Charlie Young Jensen Hughes Contractors Glenn Stewart Exelon Generating Company, LLC Shannon Rafferty-Czincila Exelon Generating Company, LLC Jeffery Stone Exelon Generating Company, LLC Eugene Kelly Exelon Generating Company, LLC Dana DeAngelis Exelon Generating Company, LLC Roy Linthicum Exelon Generating Company, LLC Philip Tarpinian Exelon Generating Company, LLC Jeremy Thoryk Exelon Generating Company, LLC Enclosure

ML21071A102 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NAME CDukehart VSreenivas JBurkhardt DATE 03/10/2021 03/10/2021 3/15/2021 OFFICE NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME JDanna VSreenivas DATE 03/24/2021 03/24/2021