ML25140A072

Slides for Pre-Application Meeting VC Summer Mtc Verification LAR

ML25140A072
Person / Time
Site:	Summer
Issue date:	05/27/2025
From:	Dominion Energy
To:	Division of Operating Reactor Licensing
Miller, GE
References
Download: ML25140A072 (1)

Text

Dominion Energy Pre-Submittal Meeting Update on License Amendment Request for Moderator Temperature Coefficient Analytical Verification 1

May 27, 2025

• Summary of Analytical Verification

• Changes to Submittal Approach

• Fleet Report Contents

• Proposed Changes

• Conclusions

• Schedule

• Acronyms Agenda 2

May 27, 2025

• Based on Measured versus Predicted (M-P) comparisons from ~100 startups across the Dominion Energy fleet, when the overall measurement uncertainty is small (e.g. at BOC startup conditions), the comparisons show that the predicted tools (CMS5 or ANC9) predict MTC within +2 pcm/°F at all expected conditions.

• Analytical Verification (AV) compares predicted MTC values that have been augmented for measurement uncertainty factors to confirm the reload core is operating within the MTC TS/COLR limits.

• This involves adding an appropriate uncertainty (+ 2.0 pcm/°F) to the most limiting calculated value for BOC or EOC, and confirming the value remains within required limits throughout the entire core life.

• Additional operational penalties are added to the margin assessment for the EOC surveillance to account for uncertainty associated with the data and evolution for EOC measurement.

Summary of Analytical Verification 3

May 27, 2025

• During the previous pre-submittal meeting in August 2024, the NRC staff raised questions about use of NRC-approved analytical methods to satisfy the MTC TS surveillance.

• Fleet Report DOM-NAF-4 has been written to describe the methodology that will be utilized for AV. The report will be submitted as an attachment to the LAR.

• LAR revises VCS TS and implements the methodology of DOM-NAF-4.

• Dominion Energy will be requesting a 12-month review period in order to support usage of AV for EOC surveillance during Cycle 30 (Spring 2027).

• LARs for MPS3 and NAPS will be submitted following approval of DOM-NAF-4 and the VCS LAR.

Changes to Submittal Approach 4

May 27, 2025

• Submittal Package will include:

o Fleet Report DOM-NAF-4 (methodology) o Technical Basis for the change o Marked up TS pages o Example TS Bases changes (for information only) o FSAR/UFSAR language additions (for information only)

Changes to Submittal Approach (cont.)

5 May 27, 2025

DOM-NAF-4 is organized into sections that cover:

• Current TS requirements for MTC surveillances at MPS3, NAPS and VCS

• BOC measurement experience and statistical analyses

• EOC measurement uncertainties and how they are included and addressed in the AV process

• Overview of the AV process, including high-level steps that summarize how to perform both BOC and EOC verifications

• Detailed explanations of both BOC and EOC AV processes, including application criteria and sample calculations

• Conclusions and References Fleet Report Contents 6

May 27, 2025

• Change TS 4.1.1.3.a/b to read: The MTC shall be verified by measurement or analytical confirmation

• Additional requirement for TS 4.1.1.3.b that if the 300 ppm surveillance is not met, measurement will be performed.

Proposed TS Changes 7

May 27, 2025

• Delete footnote for TS 4.1.1.3 referencing WCAP-13749-P-A

• Remove reference to WCAP-13749-P-A in TS 6.9.1.11.

Proposed TS Changes (cont.)

8 May 27, 2025

• TS Bases for 3/4.1.1.3 Additional Changes (For Information Only) 9 May 27, 2025

• UFSAR Section 4.3.2.3.2.1 Additional Changes (For Information Only, cont.)

10 May 27, 2025

• Dominion Energy is submitting a LAR to allow for use of AV to satisfy MTC TS surveillances for VCS.

• A fleet report (DOM-NAF-4) containing the AV methodology will be included in the LAR submittal for NRC staff review and approval.

• This report will be explicitly referenced in the FSAR as the method of evaluation for analytically verifying MTC TS surveillances.

• Following approval of the methodology and VCS LAR, subsequent LARs will be submitted for MPS3 and NAPS.

Conclusions 11 May 27, 2025

• NRC Pre-Submittal Meeting on 05/27/2025

• LAR Submittal to the NRC expected by end of August 2025

• NRC Approval requested by end of August 2026 Schedule 12 May 27, 2025

AV Analytical Verification BOC Beginning of Cycle COLR Core Operating Limits Report EOC End of Cycle LAR License Amendment Request M-P Measured versus Predicted MPS3 Millstone Power Station Unit 3 Acronyms 13 MTC Moderator Temperature Coefficient NAPS North Anna Power Station NRC Nuclear Regulatory Commission SR Surveillance Requirement TS Technical Specifications VCS V.C. Summer Nuclear Station May 27, 2025