ML25134A031

Request for Additional Information LAR to Revise SR to Reduced Test Pressure and Leakage Rate for MSIVs

ML25134A031
Person / Time
Site:	Nine Mile Point
Issue date:	05/14/2025
From:	Richard Guzman NRC/NRR/DORL/LPL1
To:	Reynolds R Constellation Energy Generation
References
EPID L-2025-LLA-0019
Download: ML25134A031 (1)

Text

From:

Richard Guzman To:

Reynolds, Ronnie J:(Constellation Nuclear)

Cc:

Hipo Gonzalez; Rossi, Matthew: (Constellation Nuclear)

Subject:

NINE MILE POINT NUCLEAR STATION, UNIT NO. 2 - REQUEST FOR ADDITIONAL INFORMATION Re: LAR to Revise SR to Reduced Test Pressure and Leakage Rate for MSIVs(EPID L-2025-LLA-0019)

Date:

Wednesday, May 14, 2025 7:00:46 AM

Ron, On May 5, 2025, the U.S. Nuclear Regulatory Commission (NRC) staff sent Constellation Energy Generation, LLC (the licensee) the subject Request for Additional Information (RAI) as a draft e-mail. This RAI supports the NRC staffs review of the licensees January 29, 2025 (ML25029A181), license amendment request (LAR) for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2).In the LAR, the licensee proposed changes to the NMP2 Technical Specifications (TS) Surveillance Requirement (SR) 3.6.1.3.12 to reduce the main steam isolation valve (MSIV) test pressure value from >40 pounds per square inch gauge (psig) to >25 psig. In addition, the licensee proposed a corresponding change to the maximum allowable leakage through each MSIV from <50 standard cubic feet per hour (scfh) to <39 scfh.

On May 13, 2025, you indicated that a clarification call was not necessary to respond to the information request. Updated below is the official RAI. As we discussed, please respond to this RAI within 30 days of this e-mail communication or no later than June 16, 2025. This email communication will be placed in ADAMS as an official agency record. Please contact me if you have any questions concerning this request.

Thank you, Richard V. Guzman Sr. Project Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Phone: 301-415-1030 Richard.Guzman@nrc.gov

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REQUEST FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST TO REVISE SURVEILLANCE REQUIREMENT 3.6.1.3.12 CONSTELLATION ENERGY GENERATION, LLC NINE MILE POINT NUCLEAR STATION, UNIT 2 DOCKET NO. 50-410 (EPID: L-2025-LLA-0019

INTRODUCTION By letter dated January 29, 2025, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25029A181), Constellation Energy Generation, LLC (the licensee), submitted a license amendment request (LAR) for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2).Specifically, the licensee requested changes to the NMP2 Technical Specifications (TS) Surveillance Requirement (SR) 3.6.1.3.12 to reduce the main steam isolation valve (MSIV) test pressure value from >40 pounds per square inch gauge (psig) to >25 psig. In addition, the licensee is requesting a corresponding change to the maximum allowable leakage through each MSIV from <50 standard cubic feet per hour (scfh) to <39 scfh.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in the submittal and has determined that additional information as requested in the below is needed to complete its review. This request for additional information (RAI) is necessary for the staff to evaluate the licensees scaled approach for the new maximum allowable leakage value, to ensure that the leakage considered in the licensees accident analysis is still being met, and to confirm that applicable regulations are met.

REGULATORY BASIS The regulation at Title 10 of the Code of Federal Regulations (10 CFR), Section 50.54(o),

requires primary reactor containments for water-cooled power reactors be subject to the requirements of Appendix J to 10 CFR Part 50, Leakage Rate Testing of Containment of Water-Cooled Nuclear Power Plants. Appendix J specifies containment leakage testing requirements, including the types required to ensure the leak-tight integrity of the primary reactor containment and systems and components which penetrate the containment.In addition, Appendix J discusses leakage rate acceptance criteria, test methodology, frequency of testing and reporting requirements for each type of test.

The regulation at 10 CFR 50.36(c)(3) requires TS to include items in the Surveillance Requirements category, which are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.

REQUEST FOR ADDITIONAL INFORMATION The licensee is requesting to lower the MSIV test pressure value from >40 psig to >25 psig and states thatthis proposed reduction in test pressure would also require an adjustment to the maximum allowable leakage through each MSIV to account for the change in test pressure. As a result, the licensee is proposing to adjust the maximum allowable leakage through each MSIV from 50 scfh to 39 scfh. Specifically, the licensee states in the LAR:

By scaling the maximum allowable leakage at Pa (50 SCFH) as listed in the NMP2 TS to the proposed test pressure, the equivalent maximum allowable leakage limit through each MSIV will be 39 SCFH when tested at 25 psig.

The NRC staff noted that the licensee did not provide the method used to calculate the new maximum allowable leakage limit. That NRC staff requests the licensee to (1) provide a more detailed explanation of the scaled approach, specifying the exact method (e.g.,

conversion factor) used to determine the new maximum allowable leakage limit and (2) verify that the new proposed leakage rate is bounded by the accident analyses in the current licensing basis.

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From: Richard Guzman Richard.Guzman@nrc.gov Sent: Monday, May 5, 2025 3:21 PM To: Reynolds, Ronnie J:(Constellation Nuclear) Ronnie.Reynolds@constellation.com Cc: Hipo Gonzalez Hipolito.Gonzalez@nrc.gov

Subject:

NINE MILE POINT NUCLEAR STATION, UNIT NO. 2 - DRAFT Request for Additional Information Re: LAR to Revise SR to Reduced Test Pressure and Leakage Rate for MSIVs(EPID L-2025-LLA-0019)

Ron, By letter dated January 29, 2025 (ADAMS Accession No. ML25029A181), Constellation Energy Generation, LLC (CEG, the licensee) submitted a license amendment request (LAR) for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2). The proposed amendment would modify NMP2 Technical Specification (TS) requirements to reduce the main steam isolation valve (MSIV) test pressure, Specifically, the licensee proposed to revise NMP2 TS Surveillance Requirement (SR) 3.6.1.3.12 to reduce the main steam isolation valve (MSIV) test pressure value from >40 pounds per square inch gauge (psig) to >25 psig. In addition, the proposed amendment would adjust the maximum allowable leakage through each MSIV to account for the change in test pressure.

The NRC staff has determined that additional information is needed to complete its review, as described in the request for additional information (RAI) shown below. This RAI is identified as DRAFT at this time to confirm your understanding of the information needed by the NRC staff to complete its evaluation. Please let me know your groups availability for a clarification call if desired, and I will coordinate availabilities w/

the NRC technical staff. I would like to hold the call within the next two weeks, if needed, as I plan to issue the questions as an official RAI no later than May 23rd.

Thanks, Rich Guzman Sr. PM, Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Phone: (301) 415-1030 Richard.Guzman@nrc.gov