ML24274A237

– Supplemental Information Needed for Acceptance of Requested Licensing Action Regarding Primary Containment Leakage Technical Specifications

ML24274A237
Person / Time
Site:	Limerick
Issue date:	10/07/2024
From:	Audrey Klett NRC/NRR/DORL/LPL1
To:	Rhoades D Constellation Energy Generation
References
EPID L-2024-LLA-0115
Download: ML24274A237 (1)

Text

October 7, 2024 David P. Rhoades Senior Vice President President and Chief Nuclear Officer Constellation Energy Generation, LLC 4300 Winfield Rd.

Warrenville, IL 60555

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2 - SUPPLEMENTAL INFORMATION NEEDED FOR ACCEPTANCE OF REQUESTED LICENSING ACTION REGARDING PRIMARY CONTAINTMENT LEAKAGE TECHNICAL SPECIFICATIONS (EPID L-2024-LLA-0115)

Dear David Rhoades:

By letter dated August 28, 2024 (Agencywide Documents Access and Management System Accession No. ML24241A195), Constellation Energy Generation, LLC (the Licensee) submitted a license amendment request for Limerick Generating Station, Units 1 and 2. The proposed amendment would modify Technical Specification 3.6.1.2, Containment Systems - Primary Containment Leakage, to verify the allowable leak rate through each main steam line and the total leak rate through all four main steam lines.

The purpose of this letter is to provide the results of the U.S. Nuclear Regulatory Commission (NRC) staffs acceptance rev iew of this amendment request. The acceptance review was performed to determine if there is sufficient technical information in scope and depth to allow the NRC staff to complete its detailed tec hnical review. The acceptance review is also intended to identify whether the application has any readily apparent information insufficiencies in its characterization of the regulatory requir ements or the licensing basis of the plant.

Consistent with Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR), an application for an amendment to a license (inclu ding the technical specifications) must fully describe the changes requested, and following as far as applicable, the form prescribed for original applications. Section 50.34 of 10 CFR addresses the content of technical information required. This section stipulates that the submittal address the design and operating characteristics, unusual or novel design features, and principal safety considerations.

The NRC staff has reviewed your application and concluded that the information delineated in the enclosure to this letter is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed amendment request in terms of regulatory requirements for the protection of public health and safety and the environment.

To make the application complete, the NRC sta ff requests that the licensee supplement the application to address the information requested in the enclosure by October 25, 2024. This will D. Rhoades

enable the NRC staff to begin its detailed technical review. If the information responsive to the NRC staffs request is not received by the above date, the application will not be accepted for review pursuant to 10 CFR 2.101, and the NRC will cease its activities associated with the application. If the application is subsequently accepted for review, you will be advised of any further information needed to support the staffs detailed technical review by separate correspondence.

The information requested and associated time frame in this letter were discussed with Stephen Flickinger of your staff on October 7, 2024.

If you have any questions, please contact me at (301) 415 -0489 or by email to Audrey.Klett@nrc.gov.

Sincerely,

/RA/

Audrey Klett, Senior Project Manager Plant Licensing Branch 1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket Nos. 50-352 and 50-353

Enclosure:

Supplemental Information Needed

cc: Listserv

SUPPLEMENTAL INFORMATION NEEDED IN SUPPORT OF REVIEW OF LICENSE AMENDMENT REQUEST TO MODIFY TECHNICAL SPECIFICATION 3.6.1.2 CONSTELLATION ENERGY GENERATION LLC LIMERICK GENERATING STATION, UNITS 1 AND 2 DOCKET NOS. 50-352 AND 50-353

By letter dated August 28, 2024 (Agencywide Documents Access and Management System Accession No. ML24241A195), Constellation Energy Generation, LLC (the licensee) submitted a license amendment request (LAR) for Limerick Generating Station, Units 1 and 2. The proposed amendment would modify Technical Specif ication (TS) 3.6.1.2, Containment Systems - Primary Containment Leakage, to verify the allowable leak rate through each main steam line (MSL) and the total leak rate through all four MSLs. The U.S. Nuclear Regulatory Commission (NRC) staff identified the following in formation insufficiencies that the licensee would need to address for the NRC staff to complete its acceptance review of the application.

Acceptance Review Information Insufficiencies

1. The LAR does not have sufficient justifica tion for the NRC to evaluate whether the requested change will ensure that (1) the assu med leakage rates of 200 standard cubic feet per hour (scfh) combined or 100 scfh per steam line (tested at 22 pounds per square inch gauge) will not be exceeded and (2) the MSLs and main steam isolation valves (MSIVs) would be operable when TS 3.6.1.2 is applicable. For example:

The LAR does not describe the test methods for determining leakage and operability, such as the arrangement(s) used for testing MSIV leakage per ANSI/ANS-46-8-1994 (LAR Reference 3) and how maximum and minimum pathway leakage rate (MXPLR and MNPLR) are used.

The LAR does not describe the licensing basis (location, content, and acceptance criteria) for how MSIV and MSL leakage are determined, including test methods, analysis requirements, and applicability of 10 CFR Part 50, Appendix J methodology given the exemptions noted in condition 2.D in each units operating license.

The LAR does not describe how the changes ensure that a single failure of any MSIV, at any time, will not result in exceeding analyzed limits (e.g., how using the MNPLR acceptance criteria is consistent with the offsite dose assumption that a valve in each MSL fails to close).

Enclosure

The LAR does not describe how the proposed changes would retain the safety function of the MSIVs and MSLs considering that the Limerick TS bases state, Operating experience with the main steam line isolation valves has indicated that degradation has occasionally occurred in the leak tightness of the valves; therefore, the special requirement for testing these valves.

2. The LAR states that the proposed changes to TS are consistent with NUREG-1433, Revision 5, Standard Technical Specifications - General Electric BWR/4 Plants (ML21272A357 (specifications) and ML21272A358 ( bases)); however, the LAR is missing justification for this assertion. The consistency was not apparent given that the improved standard technical specifications (STS) have leakage requirements for each MSIV, not each MSL as proposed in the LAR. The STS requirements are summarized as follows:

STS surveillance requirement (SR) 3.6.1.3.13 establishes a leakage rate for each MSIV but not each MSL. This is emphasized in the STS bases for this SR.

The required action for STS 3.6.1.3, Condition D requires that MSIV leakage rate, not the MSL leakage rate, be restored in 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

3. The LAR did not discuss how the proposed change from MSIV Leakage to Main Steam Line Leakage would be consistent with the regulatory position provided in Regulatory Guide (RG) 1.183, Appendix A Assumptions fo r Evaluating the Radiological Consequences of a LWR Loss-of-Coolant Accident, Assumptions on Main Steam Isolation Valve Leakage in BWRs. Specifically, per its February 27, 2004 LAR related to application of Alternative Source Term (ML040980153, as supplemented), the licensee used the term MSIV Leakage consistently throughout the entire submittal to be consistent with regulatory position in RG 1.183 which uses MSIV Leakage to perform accident dose analysis, as opposed to Main Steam Line Leakage.

ML24274A237 OFFICE NRR/DORL/LDATA/PM NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NAME RDavis AKlett KZeleznock DATE 09/26/2024 09/26/2024 10/01/2024 OFFICE NRR/DSS/SCPB/BC NRR/DSS/STSB/BC NRR/DRA/ARCB/BC NAME MValentin SMehta KHsueh DATE 09/27/2024 09/27/2024 09/26/2024 OFFICE NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME HGonzalez AKlett DATE 09/30/2024 10/07/2024