ML23199A283

Request for Additional Information (E-mail Dated 7/18/2023) LAR to Revise the Pressure-Temperature Limits

ML23199A283
Person / Time
Site:	Millstone
Issue date:	07/18/2023
From:	Richard Guzman NRC/NRR/DORL/LPL1
To:	Sinha S Dominion Energy Nuclear Connecticut
References
EPID L-2023-LLA-0009
Download: ML23199A283 (1)

Text

From: Richard Guzman To: Shayan Sinha Cc: Hipo Gonzalez

Subject:

Millstone Unit 3 - REQUEST FOR ADDITIONAL INFOMATION - LAR to revise the Pressure-Temperature Limits (EPID L-2023-LLA-0009)

Date: Tuesday, July 18, 2023 3:21:58 PM

Shayan, On June 29, 2023, the U.S. Nuclear Regulatory Commission (NRC) staff sent Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee) the subject Request for Additional Information (RAI) as a draft e-mail. This RAI is regarding the licensees January 13, 2023 (ML23013A224), license amendment request to revise the Technical Specifications (TSs) for Millstone Power Station, Unit 3. The proposed changes would revise the applicability term for the pressure-temperature (P-T) limits.

The NRC staff and DENC held a conference call on July 18, 2023, to discuss clarifications on the draft RAI. Updated below is the official (final) RAI. As discussed on the call, please provide a response to these questions within 45 days of this e-mail communication or no later than September 1, 2023. A publicly available version of this communication will be placed in ADAMS, the NRCs official document repository system. Please contact me if you have any questions concerning this request.

Richard V. Guzman Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Office: O-9C7 l Phone: (301) 415-1030 Richard.Guzman@nrc.gov

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REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING LICENSE AMENDMENT REQUEST TO REVISE THE PRESSURE-TEMPERATURE LIMITS MILLSTONE POWER STATION, UNIT NO. 3 DOCKET NO. 50-423 (EPID: L-2023-LLA-0009)

By letter dated January 13, 2023 (Agencywide Document Access and Management System (ADAMS) Accession No. ML23013A224), Dominion Energy Nuclear Connecticut, Inc.

(DENC, the licensee) submitted a license amendment request (LAR) to revise the Technical Specifications (TSs) for Millstone Power Station, Unit 3 (MPS3). Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.90, the LAR proposes revision to the applicability term for the pressure-temperature (P-T) limits. 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.

RAI-1

Table 2 in Attachment 3, Evaluation of Adjusted Reference Temperatures and Reference Temperature Shifts, of the LAR presents Docketed Beltline Chemistries and Initial RTNDT Values from Millstone LRA, and identifies the initial RTNDT value for intermediate shell plate B9805-1 as 80.0°F. However, in Tables 1, 6, 7 and 8 of Attachment 3, as well as Table 4.2-2 of the Millstone Unit 3 License Renewal Application (ML040260103), the initial RTNDT value for intermediate shell plate B9805-1 is shown as 60.0°F. Identify the correct initial RTNDT value for intermediate shell plate B9805-1. Explain the basis for this discrepancy.

RAI-2

Figure 5, Millstone Unit 3 RPV Rollout Map, in Attachment 3 of the LAR identifies the MPS3 reactor pressure vessel (RPV) shell plates. The nozzle shell plates are identified as Plates B9404-1, B9404-2, and B9404-3. By letter dated November 19, 2020 (ML20324A703), DENC requested a Measurement Uncertainty Recapture Power Uprate.

Table IV-2, Calculated Neutron Fluence Projections of RV Beltline and Extended Beltline Materials for MPS3 at 54 and 60 EFPY, in that document identifies the Nozzle Shell Plates as B9804-1, B9804-2, and B9804-3. Provide confirmation of the plate identifications for RPV Nozzle Shell Plates in MPS3.

RAI-3

On October 14, 2014, the NRC issued Regulatory Issue Summary (RIS) 2014-11, "Information on Licensing Applications for Fracture Toughness Requirements for Ferritic Reactor Coolant Pressure Boundary Components," (ML14149A165) which clarified that the beltline definition in 10 CFR 50, Appendix G is applicable to all RPV ferritic materials with projected neutron fluence values greater than 1x1017 neutrons/centimeter-squared (n/cm2) with energy greater than one million electron volts (E > 1 MeV), and this neutron fluence threshold remains applicable for the licensed operating period.

As noted in section 3.4 of Attachment 3, RPV nozzles with projected neutron fluence values less than the 4.28 x 1017 n/cm2 threshold defined in PWROG-15109-NP-A do not require further evaluation. Table 4 in Attachment 3 presents projected neutron fluence values at 54 and 60 EFPY for all beltline RPV materials. However, all beltline materials have not been included in Tables 1, 2, 5, 6, 7 and 8 in Attachment 3.

Describe how the P-T limit curves for MPS3 consider all ferritic pressure boundary

components of the reactor vessel that are predicted to experience a neutron fluence exposure greater than 1x1017 n/cm2 (E > 1 MeV) at the end of the licensed operating period. If the current P-T limit curves do not consider all applicable ferritic pressure boundary components of the RPV that are predicted to experience a neutron fluence exposure greater than 1x1017 n/cm2 (E > 1 MeV) at the end of the licensed operating period, provide appropriately revised P-T limit curves for review. Provide all inputs and projected values for each beltline material. Similarly, for RTPTS, provide all inputs and projected values for each beltline material.

RAI-4

As required by 10 CFR 50.61, To verify that RTNDT for each vessel beltline material is a bounding value for the specific reactor vessel, licensees shall consider plant-specific information that could affect the level of embrittlement. This information includes but is not limited to the reactor vessel operating temperature and any related surveillance program results.

The licensee stated the MPS3 surveillance weld material (heat 4P6052) is additionally represented in surveillance capsules at Seabrook and at a non-U.S. plant. The test results and information for the Seabrook reactor vessel material surveillance program are publicly available, including:

Yankee Atomic Electric Company, Analysis of Seabrook Station Unit 1 Reactor Vessel Surveillance Capsule U, June 26, 1992 (ML20099J203)

Duke Engineering and Services, Report No. DES-NFOA-98-01 Analysis of Seabrook Stations Unit 1, Reactor Vessel Surveillance Capsules U & Y, May 5, 1998 (ML20248L409)

WCAP-16526-NP, Rev. 0, "Analysis of Capsule V from FPL Energy - Seabrook Unit 1 Reactor Vessel Radiation Surveillance Program," March 31, 2006 (ML061030088)

WCAP-18607-NP, Analysis of Capsule X from the NextEra Energy Seabrook Unit 1 Reactor Vessel Radiation Surveillance Program, September 30, 2021 (ML21277A388)

Provide the results of an evaluation of the applicability, including credibility, of the surveillance program results pertaining to weld heat 4P6052. Describe how these results were taken into consideration in evaluating the RTNDT of weld heat 4P6052 at MPS3.

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From: Richard Guzman <Richard.Guzman@nrc.gov>

Sent: Thursday, June 29, 2023 9:34 AM

To: Shayan Sinha (Services - 6) <Shayan.Sinha@dominionenergy.com>

Subject:

Millstone Power Station, Unit 3 - DRAFT Request for Additional Information - License Amendment Request to Revise Pressure-Temperature Limits (EPID: L-2023-LLA-0009)

Shayan, By letter dated January 13, 2023 (ADAMS Accession No.ML23013A224), Dominion Energy Nuclear Connecticut, Inc. (DENC, the licensee) submitted a license amendment request to revise the Technical Specifications (TSs) for Millstone Power Station, Unit 3. The proposed changes would revise the applicability term for the pressure-temperature (P-T) limits.

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. If youd like to have a clarification call, please let me know and I will coordinate availabilities w/the NRC technical staff. I intend to send out the questions below as official by July 12th, if possible.

Thank you,

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Rich Guzman Sr. PM, Division Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Office: O-9C7 l Phone: (301) 415-1030 Richard.Guzman@nrc.gov