ML21019A583

Summary of Public Meeting with Southern Nuclear Operating Company, Inc., Regarding a Proposed License Amendment Request to Change the Allowable Values for Surveillance Requirements Related to Technical Specification 3.3.5.2,

ML21019A583
Person / Time
Site:	Vogtle
Issue date:	01/29/2021
From:	John Lamb Plant Licensing Branch II
To:	Gayheart C Southern Nuclear Operating Co
John Lamb - NRR/DORL 301-415-3100
References
EPID L-2020-LRM-0112
Download: ML21019A583 (6)

Text

January 29, 2021 LICENSEE: Southern Nuclear Operating Company, Inc.

FACILITY: Vogtle Electric Generating Plant, Units 1 and 2

SUMMARY

OF JANUARY 19, 2021, PUBLIC MEETING WITH SOUTHERN NUCLEAR OPERATING COMPANY, INC., REGARDING A PROPOSED LICENSE AMENDMENT REQUEST TO CHANGE THE ALLOWABLE VALUES FOR SURVEILLANCE REQUIREMENTS RELATED TO TECHNICAL SPECIFICATION 3.3.5.2, LOSS OF POWER (LOP) INSTRUMENTATION, FOR VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 (EPID NO. L-2020-LRM-0112)

On January 19, 2021, a Category 1 public 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) to change the Allowable Values (AVs) for Surveillance Requirements (SRs) related to Technical Specification (TS) 3.3.5.2, Loss of Power (LOP) Instrumentation, for Vogtle Electric Generating Plant (Vogtle), Units 1 and 2.

A list of attendees is provided as an Enclosure.

On December 8, 2020 (Agencywide Document and Access Management System (ADAMS) Accession No. ML20346A050), the meeting was noticed on the NRC public webpage.

The SNC presented slides contained in ADAMS Accession No. ML21011A053.

Introduction The NRC staff opened the meeting with introductory remarks and introduction of the attendees.

The SNC staff discussed the following topics: (1) background information on the LOP function, and (2) the proposed LAR.

Background

There are four Emergency Diesel Generator (EDG) start circuits at Vogtle. The EDG start logic initiates on (1) loss of voltage, and (2) degraded voltage. The Vogtle EDG start logic is 2 out of 4 logic. The Vogtle TS requirements are 4 channels of loss of voltage and degraded voltage Function Operable per safety related 4.16 kiloVolt bus. The Vogtle Channels are Operable when the trip setpoints meet its required values and delay times, and the Channels are conservative to its AV.

The Vogtle accident analyses credit the loading of the EDGs based on a loss of offsite power (LOOP) during a loss-of-coolant accident. The Vogtle EDG loading time is included in the delay time of each safety system component following a LOOP. The Vogtle trip setpoint for the loss of voltage and the degraded voltage Functions are derived from the Analytical Limits (ALs) for these Functions presented in Chapter 15 of the Updated Final Safety Analysis Report (UFSAR).

The International Society of Automation (ISA) published a standard titled, ISA-S67.04-1994, Setpoints for Nuclear Safety-Related Instrumentation.

In December 1999, the NRC staff issued Regulatory Guide (RG) 1.105, Revision 3, Setpoints for Safety-Related Instrumentation (ADAMS Accession No. ML993560062). The RG 1.105, Revision 3, stated:

This guide describes a method acceptable to the NRC staff for complying with the NRC's regulations for ensuring that setpoints for safety-related instrumentation are initially within and remain within the technical specification limits. The guide is being revised to endorse Part l of ISA-S67.04-1994, Setpoints for Nuclear Safety-Related Instrumentation. This standard provides a basis for establishing setpoints for nuclear instrumentation for safety systems and addresses known contributing errors in the channel.

Part II, "Methodologies for the Determination of Setpoints for the Nuclear Safety-Related Instrumentation," of ISA-S67.04-1994 is not addressed by this regulatory guide.

Vogtle uses Method 3 established in ISA-S67.04-1994 to calculate AVs. Vogtle calculates the AVs using Method 3 by the following:

The Nominal Trip Setpoint (NTS) is determined from the AL in UFSAR Chapter 15. The NTS separation from the AL is based on a combination of all errors.

The AV is then determined from the NTS and is based on errors present during calibration.

The NRC Regulatory Issue Summary (RIS) 2006-17, NRC Staff Position on the Requirements of 10 CFR 50.36, Technical Specifications, Regarding Limiting Safety System Settings During Periodic Testing and Calibration of Instrument Channels, dated August 24, 2006 (ADAMS Accession No. ML051810077), discusses issues that could occur during testing of limiting safety system settings and which, therefore, may have an adverse effect on equipment operability. The RIS 2006-17 also represents an approach that is acceptable to the NRC staff for addressing these issues for use in licensing actions.

Proposed LAR SNC stated that the AV contained in the current TS is the AL from UFSAR Chapter 15. SNC said that using ALs as AVs conflicts with the Standard TSs and creates the possibility that the trip setpoints will be insufficient to perform their required trip function. SNC proposes to change the TS to replace the current AV with the appropriate value.

SNC stated that the current Vogtle TS SR 3.3.5.2 states the following:

Loss of voltage AV > 2912 Volts (V) with a time delay of < 0.8 second.

Degraded voltage AV > 3683 V with a time delay of < 20 seconds.

SNC said that the proposed Vogtle TS SR 3.3.5.2 would state the following:

Loss of voltage AV > 2958.2 V with a time delay of < 0.8 second.

Degraded voltage AV > 3729.2 V with a time delay of < 20 seconds.

SNC stated that the Vogtle TS AV for Loss of Voltage > [NTS - (Rack Calibration Accuracy (RCA) X span primary voltage)], which is > [2975 VAC - (0.0032 x 5250 VAC)], and results in > 2958.2 VAC.

SNC stated that the Vogtle TS AV for Degraded Voltage > [NTS - (RCA X span primary voltage)],

which is > [3746 VAC - (0.0032 x 5250 VAC)], and results in > 3729.2 VAC. SNC said that NTS is from TS SR 3.3.5.2 and is not changed by the proposed request.

NRC Questions to SNC The NRC staff questioned SNC if this proposed LAR was a non-conservative TS change. The NRC staff questioned if SNC would be using RG 1.239, Licensee Actions to Address Nonconservative Technical Specifications, November 2020 (ADAMS Accession No. ML20294A510). The SNC staff stated that the current Vogtle TS is nonconservative and it is being treated administratively. The SNC staff said that the AV contained in the current Vogtle TS is the AL from UFSAR Chapter 15.

The NRC staff informed SNC that the RG 1.105 only endorsed Part 1 of ISA-S67.04-1994, and that the proposed Method 3 is contained in Part 2 of ISA-S67.04-1994. The SNC staff was aware that the NRC staff has not endorsed Method 3 contained in Part 2 of ISA-S67.04-1994; however, the SNC staff further stated that the NRC staff has approved the use of Method 3 for other licensees. The NRC staff stated that if Method 3 was previously approved, those precedents may be included in the proposed LAR to help streamline the NRC staffs proposed review. The NRC staff will review the proposed method as described in the proposed LAR and will review any precedents supplied in the proposed LAR. It should be noted that the proposed AVs will be reviewed independently and discretely from Part 2 of ISA S67.04-1994. Part 2 of the standard should not be cited in the proposed LAR to avoid the misinterpretation that should this proposed LAR be approved eventually, the NRC would approve/endorse Part 2 of ISA Std. 67.04-1994.

The NRC staff inquired about the potential transformer ratio, the current AL in Chapter 15 of the UFSAR, the summary of the calculations for (i) the as-found and as-left tolerance limits of the instruments, and (ii) the RCA, and a discussion on the calculation methodology. The SNC staff stated that all that information will be included in the proposed LAR.

The SNC staff stated that the proposed LAR will be submitted in the first quarter of 2021 and SNC will request a 12-month review.

Public Questions to NRC There was one member of the public in attendance, but the member of the public had no questions for the NRC staff.

Closing The NRC staff made no regulatory decisions during the meeting.

Once received, the NRC staff will perform a thorough review of the proposed LAR and 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 2:45 pm (Eastern time).

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

/RA/

John G. Lamb, Senior Project Manager Plant Licensing Branch, II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425

Enclosure:

List of Attendees cc w/encls: Distribution via Listserv

LIST OF ATTENDEES JANUARY 19, 2021, PUBLIC MEETING WITH SOUTHERN NUCLEAR COMPANY REGARDING CHANGE TO ALLOWAGE VALUE FOR SURVEILLANCE REQUIREMENT FOR TECHNICAL SPECIFICATION 3.3.5.2 VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 ATTENDEE REPRESENTING John G. Lamb NRC Mike Markley NRC Brett Titus NRC Tarico Sweat NRC Hang Vu NRC Hari Kodali NRC Khoi Nguyen NRC Ken Lowery SNC Larry Smith SNC Patricia Furio Enercon Ken Nicely Public (Exelon)

Enclosure

PKG ML20281A326 Meeting Notice: ML20346A050 Meeting Summary: ML21019A583; Slides: ML21011A053 OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA DEX/EICB/BC DORL/LPL2-1/BC DORL/LPL2-1/PM NAME JLamb KGoldstein MWaters SWilliams for MMarkley JLamb DATE 01/19/2021 01/27/2021 01/27/2021 01/28 /2021 01/29/2021