ML24290A158

Summary of Observation Pre-Submittal Meeting Held with Southern Nuclear Operating Company Regarding a Proposed License Amendment Request to Change Table 3.3.8-1 for Vogtle Electric Generating Plant, Units 3 & 4

ML24290A158
Person / Time
Site:	Vogtle
Issue date:	10/24/2024
From:	John Lamb NRC/NRR/DORL/LPL2-1
To:	Southern Nuclear Operating Co
Shared Package
ML24290A166	List: ML24290A158
References
EPID L-2024-LRM-0116
Download: ML24290A158 (1)

Text

October 24, 2024

LICENSEE: Southern Nuclear Operating Company, Inc.

FACILITY: Vogtle Electric Generating Plant, Units 3 and 4

SUMMARY

OF OCTOBER 15, 2024, OBSERVATION PRE-SUBMITTAL MEETING HELD WITH SOUTHERN NUCLEAR OPERATING COMPANY, INC.,

REGARDING A PROPOSED LICENSE AMENDMENT REQUEST TO CHANGE TABLE 3.3.8-1 FOR VOGTLE ELECTRIC GENERATING PLANT, UNITS 3 AND 4 (EPID L-2024-LRM-0116)

On October 15, 2024, an Observation meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Southern Nuclear Operating Company, Inc. (SNC, the licensee). The purpose of the meeting was for SNC to describe its plan to submit a license amendment request (LAR) for Vogtle Electric Generating Plant (Vogtle), Units 3 and 4.

SNC is proposing to add to Technical Specification (TS) Table 3.3.8-1 a new T cold - High function to for passive residual heat removal (PRHR) actuation logic at Vogtle, Units 3 and 4.

A list of attendees is provided as an Enclosure.

On October 1, 2024 (Agencywide Document s and Access Management System (ADAMS)

Accession No. ML24275A131), the meeting wa s noticed on the NRC public webpage.

The NRC staff opened the meeting with introductory remarks and a roll call of the attendees.

The SNC representative presented slides contained in ML24282A982 and ML24289A235.

SNC representatives discussed the following topics: (1) background - reason for the proposed change, (2) PRHR heat exchanger (HX) actuation logic, (3) TS 3.3.8 planned change, (4) schedule, and (6) discussion.

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Background===

SNC representative stated that the reason for the proposed change is to address the Haiyang, Unit 2, event that occurred on October 17, 2018. SNC representative said that the Haiyang, Unit 2, feedwater pump tripped that led to a reactor trip, and a subsequent start-up feedwater (SFW) initiation; this resulted in a decrease in the cold leg temperatures. The Haiyang, Unit 2, operators attempted to prevent a safeguards signal from being generated on T cold - Low-2. This resulted in Low-2 Steam Generator (SG) Narrow Range (NR) level coupled with Low-2 SFW flow, which generated an automatic PRHR HX actuation, reducing T cold further leading to a safeguards actuation.

PRHR HX Actuation Logic

Vogtle, Units 3 and 4, TS 3.3.1 is Reactor Trip System (RTS) Instrumentation. The limiting condition of operation (LCO) 3.3.1 states:

The RTS instrumentation for each Function in Table 3.3.1-1 shall be OPERABLE.

Vogtle, Units 3 and 4, TS 3.3.1 is Engineered Safety Feature Actuation System (ESFAS)

Startup Feedwater Flow Instrumentation. The LCO 3.3.11 states:

Two channels of ESFAS Startup Feedwater Flow - Low 2 instrumentation for each startup feedwater line shall be OPERABLE.

Vogtle, Units 3 and 4, TS 3.3.8 is Engineered Safety Feature Actuation System (ESFAS)

Instrumentation. The LCO 3.3.8 states:

The ESFAS instrumentation channels for each Function in Table 3.3.8-1 shall be OPERABLE.

TS Table 3.3.8-1 has, in part, the following functions:

Number Function 11 RCS [Reactor Coolant System] Cold Leg Temperature (T cold) - Low 2 20 SG [Steam Generator] Narrow Range [NR] Water Level - Low 2 21 SG Wide Range Water Level - Low 2

SNC stated that the current PRHR HX actuation logic is coincidence of 2-of-4 channels below SG NR Water Level - Low-2 in either SG, after a preset time delay, coincident with 1-of-2 SFW flow - Low-2 feeding same SG. SNC said that the current PRHR HX actuation logic is coincidence of 2-of-4 channels below SG Wide Range Water Level Low-2 in either SG.

TS 3.3.8 Planned Change

SNC stated that it planned to add an RCS Cold Leg Temperature (T cold) - High to TS Table 3.3.8-1. SNC said that the proposed P RHR HX actuation logic would be coincidence of 2-of-4 channels below SG NR Water Level - Low-2 in both SGs, after a preset time delay, coincident with 1-of-2 SFW flow in both SGs and coincidence of 2-of-4 channels above T cold -

High in either loop.

SNC stated that no hardware changes are required, except for sequence of events (SOE) cards added in non-safety SOE cabinets. SNC said that it looked at the safety impacts of the loss of a normal feedwater event.

Schedule

SNC representative stated that the proposed LAR is expected to be submitted to the NRC in December 2024 with a request for NRC staff approval within 12 months after the acceptance review. SNC plans to implement the LAR during the spring 2026 refueling outage (RFO) for Vogtle, Unit 3, and the spring 2027 RFO for Vogtle, Unit 4.

Discussion The NRC staff asked the following questions:

Will the addition of Function 11b affect other limiting conditions for operation?

Can SNC describe how the system works?

Can SNC describe other events that are credited for wide range level as referred to on slide 6?

Is the loss of emergency alternating current power and feedwater line break affected by the proposed TS change?

Does the Safety Injection actuation occur for the analysis of the loss of normal feedwater event?

Which Chapter 15 events would be affected by the proposed TS change?

What is the supporting rationale for any assertions that those events are not affected by the proposed TS changes?

For the events that were affected by the proposed TS changes, what are results to demonstrate applicable acceptance criteria are met?

Will the addition of Tcold - High meet single failure criteria?

Will SNC provide its setpoint calculation and uncertainty analysis for T cold - High?

What are the required software changes for T cold - High?

Will SNC use Interim Staff Guidance #6 (ISG-6) for the proposed change?

Can SNC identify any applicable precedent LARs and that the proposed submittal considered?

Did SNC consider precedents (e.g., a simple software-only change to a Common Q (preferably) or any other digital protection system) and the resolution of requests for additional information for those precedents?

Closing Remarks

There were two members of the public in attendance. One public member asked about the decay heat for AP1000.

The NRC staff did not make any regulatory decisions during the meeting. Once received, the NRC staff will perform a thorough review of the proposed LAR. The NRC staff will make any regulatory decisions in writing in a timely manner. Public Meeting Feedback forms were available, but no comments were received.

The meeting adjourned at 11:24 am Eastern Time (ET).

Please direct any inquiries to me at John.Lamb@nrc.gov or 301-415-3100.

/RA/

John G. Lamb, Senior Project Manager Plant Licensing Branch, II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket Nos.52-025 and 52-026

Enclosure:

List of Attendees

cc: Listserv

LIST OF ATTENDEES

OCTOBER 15, 2024, PRE-SUBMITTAL MEETING WITH SOUTHERN NUCLEAR COMPANY

REGARDING A PROPOSED LICENSE AMENDMENT REQUEST TO CHANGE TABLE 3.3.8-1

VOGTLE ELECTRIC GENERATING PLANT, UNITS 3 AND 4

ATTENDEE REPRESENTING

John G. Lamb U.S. Nuclear Regulatory Commission (NRC)

Mike Markley NRC Summer Sun NRC Jo Ambrosini NRC Ravi Grover NRC Bill Truss NRC Scott Egli NRC Michael Fitzgerald NRC Nichols Soliz NRC Angelo Stubbs NRC Brian Griman NRC Theo Fanelli NRC Norbert Carte NRC

Ken Lowery Southern Nuclear Operating Company (SNC)

Ryan Joyce SNC Jim Chamberlain SNC Chris Sommer SNC Michael Coker SNC Kimberly Yennerell SNC Dan Williamson SNC Eddie Grant SNC Neil Haggerty SNC

Thomas Joseph Westinghouse Daniel Wise Westinghouse Kyle Freiberger Westinghouse Ryan Rossman Westinghouse Natalie Rodgers Westinghouse

Yan Peng Chinese Atomic Energy Susan Sterrett Public

Enclosure

PKG, ML24290A166 Meeting Notice, ML24275A131 SNC Slides, ML24282A982 SNC Slides, ML24289A235 Meeting Summary, ML24290A158 OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA DSS/SNSB/BC DORL/LPL2-1/BC DORL/LPL2-1/PM NAME JLamb KGoldstein PSahd MMarkley JLamb DATE 10/15/2024 10/17/2024 10/22/2024 10/24/2024 10/24/2024