ML23080A281

Regulatory Audit in Support of Review of the License Amendment Request to Revise Technical Specification 1.1, Use and Application Definitions, and to Add Technical Specification 5.5.23, Online Monitoring Program

ML23080A281
Person / Time
Site:	Vogtle
Issue date:	03/27/2023
From:	John Lamb Plant Licensing Branch II
To:	Brown R Southern Nuclear Operating Co
Shared Package
ML23081A059	List: ML23080A281
References
EPID L-2022-LLA-0190
Download: ML23080A281 (1)

Text

March 27, 2023

Mr. R. Keith Brown Regulatory Affairs Director Southern Nuclear Operating Co., Inc.

3535 Colonnade Parkway Birmingham, AL 35243

SUBJECT:

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 -

REGULATORY AUDIT IN SUPPORT OF REVIEW OF THE LICENSE AMENDMENT REQUEST TO REVISE TE CHNICAL SPECIFICATION 1.1, USE AND APPLICATION DEFINITIONS, AND TO ADD TECHNICAL SPECIFICATION 5.5.23, ONLINE MONITORING PROGRAM (EPID L-2022-LLA-0190)

Dear Mr. Brown:

By letter dated December 21, 2022 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML22355A588), Southern Nuclear Operating Company (SNC, the licensee) submitted a license amendment request (LAR) for Vogtle Electric Generating Plant (Vogtle), Units 1 and 2. The proposed LAR would revise Technical Specification (TS) 1.1, Use and Application Definitions, and add TS 5.5.23, Online Monitoring Program.

SNC proposes to use online monitoring (OLM) methodology as the technical basis to switch from time-based surveillance frequency for channel calibrations to a condition-based calibration frequency based on OLM results. The proposed LAR is based on the U.S. Nuclear Regulatory Commission (NRC)-approved Analysis and Measur ement Services Corporation (AMS) topical report (TR) AMS-TR-0720R2-A, Online Monitoring Technology to Extend Calibration Intervals of Nuclear Plant Pressure Transmitters (ML21235A493).

The NRC staff conducted a virtual regulatory audit between February 1 and March 21, 2023, to examine the SNCs non-docketed information on the proposed Vogtle OLM program. This audit was conducted in accordance with the audit plan dated January 20, 2023 (ML23011A274). The purpose of this audit was to gain understanding, to verify information, or to identify information that will require docketing to support the basis of the licensing or regulatory decision.

The purpose of this letter is to provide the results of the regulatory audit. Documented in the enclosed report are the observations the NRC staff identified during the audit.

Sincerely,

/RA/

John G. Lamb, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Enclosure:

Audit Report

cc: Listserv

REGULATORY AUDIT REPORT

BY THE OFFICE OF NUCLEAR REACTOR REGULATION

TO SUPPORT THE REVIEW OF THE LICENSE AMENDMENT REQUEST

TO REVISE TS 1.1 and ADD TS 5.5.23

SOUTHERN NUCLEAR OPERATING COMPANY

VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2

DOCKET NOS. 50-424 AND 50-425

DATE: February 1 to March 21, 2023

LOCATION: Remote

AUDIT TEAM MEMBERS:

Richard Stattel, Audit Team Member, NRR/DEX/EICB Joseph Ashcraft, Audit Team Member, NRR/DEX/EICB Tarico Sweat, Audit Team Member, NRR/DSS/STSB

BACKGROUND:

By letter dated December 21, 2022 (Agencywi de Documents and Access Management System (ADAMS) Accession No. ML22355A588), Southern Nuclear Operating Company (SNC, the licensee) submitted a license amendment request (L AR) for Vogtle Electric Generating Plant (Vogtle), Units 1 and 2. The proposed LAR would revise Technical Specification (TS) 1.1, Use and Application Definitions, and add TS 5.5.23, Online Monitoring Program.

The licensee proposes to use online monitoring (OLM) methodology as the technical basis to switch from time-based surveillance frequency for channel calibrations to a condition-based calibration frequency based on OLM results. The proposed LAR is based on the U.S. Nuclear Regulatory Commission (NRC)-approved Analys is and Measurement Services Corporation (AMS) topical report (TR) AMS-TR-0720R2-A, Online Monitoring Technology to Extend Calibration Intervals of Nuclear Plant Pressure Transmitters (ML21235A493).

REGULATORY AUDIT BASES:

A regulatory audit is a planned license or regulation related activity that includes the examination and evaluation of primarily non-docketed information associated with the LAR. The purpose of this audit was to gain understanding, to verify information, or to identify information that will require docketing to support the basis of the licensing or regulatory decision. This audit was conducted in accordance with NRR Office Instruction LIC-111, Regulatory Audits, Revision 1, dated October 2019 (ML19226A274), with exceptions noted within the audit plan.

The NRC staff performed this audit to support its evaluation of whether the SNC LAR can be approved per Title 10 of the Code of Federal Regulations (10 CFR), Section 50.90, Application for amendment of license, construction permit, or early site permit. The NRC staffs review will be informed by NUREG-0800, Standard Review Plan. The results of this audit are being used to enhance the NRC staffs understanding the licensees proposed OLM LAR.

AUDIT SCOPE:

This audit focused on reviewing the OLM procedures and Vogtle specific OLM reports to confirm that the Vogtle OLM program is being implemented in a manner that is consistent with the NRC approved AMS OLM topical report. A secondary purpose of this audit was to enable the NRC staff to develop a better understanding of the information being used to support the implementation of the Vogtle OLM program.

The licensee and AMS supported the audit by providing remote access to requested reports and by making appropriate staff with detailed knowledge of AMS-TR-0720R1 available for discussions with the NRC staff.

REGULATORY AUDIT ACTIVITIES:

The licensee supported the audit by making appropriate staff available for discussions who have detailed knowledge of AMS-TR-0720 R1, and the principles and bases for the OLM processes discussed in the TR. The following documents were made available for the NRC staffs review on a web-based portal throughout the duration of the audit period.

1. AMS Report SNO2201R2, OLM Amenable Tr ansmitters Report for Vogtle Units 1 and 2, December 2022.

2. AMS Report SNO2202R1, OLM Analysis Methods and Limits Report for Vogtle Units 1 and 2, December 2022.

3. AMS Report SNO2203R1, OLM Drift Monitoring Implementation Report for Vogtle Units 1 and 2, December 2022.

4. AMS Procedure OLM2201, Procedure for Online Monitoring Data Retrieval, AMS Corporation, December 2022.

5. AMS Procedure OLM2202, Procedure for Performing Online Monitoring Data Qualification and Analysis, AMS Corporation, December 2022.

6. AMS Report SNO2204R1, Noise Analysi s Technique Implementation for Vogtle Units 1 and 2, AMS Corporation, December 2022.

7. AMS Procedure NPS1501, Procedure for Noise Data Collection from Plant Sensors, AMS Corporation, March 2015.

8. AMS Procedure NAR2201, Procedure for Performing Dynamic Failure Mode Assessment Using Noise Analysis, AMS Corporation, December 2022.

Review notes for each of the audited AMS reports are provided below.

SNO2201: OLM AMENABLE TRANSMITTERS REPORT FOR VOGTLE UNITS 1 AND 2

This report addresses Steps 1 through 6 of Section 11.1.1 of the TR for the transmitters in Vogtle Units 1 and 2 that are included in the OLM program.

The report identifies groups of Pressure, Level and Flow Transmitters for each unit that qualify to be entered into the Vogtle OLM program.

The NRC staff notes that for Steam Generator Level Wide Range Loop transmitters, the OLM program will compare these transmitter signals to the narrow range level transmitters associated with each steam generator in order to accomplish OLM.

The NRC staff also noted that Table 3.35 identifies a transmitter that was not included in the AMS-TR-0720 topical report as being amenable to OLM. This transmitter model was different from all other transmitters measuring in the group. The licensee responded to this comment by explaining that this transmitter had been replaced with a newer model than the other Auxiliary Feedwater flow transmitters.

The NRC held an audit meeting with SNC on February 29 to discuss transmitter model amenability to OLM. During this meeting, the licensee and AMS explained that the transmitter model number was correct and that a justification for including this transmitter into the OLM program would be added to the SN2201 report.

The NRC staff reviewed the revised report and c onfirmed that the process for including instruments into OLM was consistent with the AMS-TR-0720 topical report.

SN02202: OLM Analysis Methods and Limits Report

This report documents OLM implementation steps 7 and 8 of Section 11.1.1 of the TR.

Step 7 - Identify Data Analysis Methods Step 8 - Establish OLM Limits

The NRC staff observed that transmitter groups with greater numbers of sensors have higher OLM limits. More transmitters in a group result in smaller Process Estimate Uncertainty (PEU).

The NRC staff also noted that the formula for calculating ECEU on page 7 of this report, Equation 2.6 seems to have an error in one of the terms of the equation. This was later confirmed to be a typographical error and was corrected in a revision to the report.

SG WR Level note: Each Steam Generator Level Wide Range transmitter is compared with the other four Steam Generator Level Narrow Range transmitters which are more accurate than the wide range level transmitter, so this service is considered as having five redundant sensors. The four Steam Generator Level Narrow Range are scaled into the wide range percent (%) scaling for the uncertainty calculations.

A table was provided in the report which provides summary data for all of the transmitter groups.

The NRC staff noted a calculation discrepancy in one of the transmitter groups. The results of the uncertainty calculations seemed to be different than the results documented in the report.

This discrepancy was discussed with the licensee and AMS during the audit call on February 23, 2023. The licensee subsequently responded by providing an update to the report SNO2202R0 which will include an explanation that one of the terms used in the calculation was intentionally excluded. A justification for modifying the calculations will also be added to the report.

The NRC staff reviewed the revised report and confir med that corrections and justifications for deviations from the AMS-TR-0720 topical report described above were provided.

SN02203: OLM Drift Monitoring Implementation Report

Purpose:

This document provides the steps that must be followed to implement OLM for transmitter drift monitoring in accordance with the U.S Nuclear Regulatory Commission (NRC)-

approved methodology developed by Analysis and Measurement Services Corporation (AMS) in Topical Report (TR) AMS-TR-0720R2-A, Online Monitoring Technology to Extend Calibration Intervals of Nuclear Plant Pressure Transmitters.

The steps described in this document are intended to be repeated during each operating cycle in order to identify transmitters to be calibrated. A total of eleven (11) steps must be performed each operating cycle to perform transmitter drift monitoring with OLM and report the results.

A description is provided of AMS software that is used to retrieve data from the plants historian.

This software ensures that the OLM data for each sensor is synchronized before OLM analysis is performed.

Another software tool is described which perform s calibration reduction. This software performs OLM analysis of data from pressure, level, and flow transmitters in nuclear facilities.

The report also describes a software tool which allows users to enter manual transmitter calibration information and calculate backstop intervals for each group of redundant sensors.

This document is primarily a plan for conducting these activities on a continuing bases for Vogtle once the OLM program is in place. It is not a report of current transmitter drift monitoring or drift data analysis activities having been perform ed. Vogtle, Units 1 or 2, data is provided in the report and the report does not include results of assessment or report of transmitters to be calibrated, though it established the processes for these activities to be performed when the OLM program is in place.

SN02204: NOISE ANALYSIS TECHNIQUE IMPLEMENTATION FOR VOGTLE UNITS 1 AND 2

This document provides the steps that must be followed to implement noise analysis for assessment of transmitter dynamic failure modes. The steps described in this document are intended to be repeated during each operating cycle for a minimum of one transmitter on a staggered basis in each redundant group which has a response time requirement to identify its dynamic failure modes.

The process involves Six (6) steps that are taken at each operating cycle at Vogtle, Units 1 and 2, to perform dynamic failure mode assessment of transmitters.

1. Select qualified noise data acquisition equipment,

2. Connect noise data acquisition equipment to plant signals,

3. Collect and store data for noise analysis,

4. Screen data for artifacts and anomalies,

5. Perform Data analysis, and

6. Review and document results.

The appendices of this document provide a listing of the transmitters to be included for OLM.

The document does not provide time response requirements of the Vogtle transmitters that are to be included in the OLM program.

OLM2201: PROCEDURE FOR ONLINE MONITORING DATA RETRIEVAL (9p)

This is a test procedure for retrieving OLM data from the plant historian using the AMS Bridge software. It is not a Vogtle specific document, so it does not describe any of the Vogtle data archival systems. It provides general steps that are followed when retrieving OLM data.

OLM2202: PROCEDURE FOR PERFORMING ONLINE MONITORING DATA QUALIFICATION AND ANALYSIS

This document outlines the general steps that are followed when performing OLM data analysis.

It is not a Vogtle specific document, so it does not describe any of the Vogtle data archival systems or provide any actual analysis of Vogtle specific data.

NPS1501: PROCEDURE FOR NOISE DATA COLLECTION FROM PLANT SENSORS

This procedure provides guidelines for the collection of noise data to determine the dynamic performance characteristics of sensors and systems in nuclear power plants and other processes. It is not a Vogtle-specific document, so it does not provide any actual noise data from Vogtle.

This procedure is used for online data acquisition from a wide variety of sensors and systems including the Vogtle pressure transmitters in the OLM program while the plant is operating at any mode that provides adequate signal amplitudes for analysis. Because the noise tests are passive and do not create any disturbance to plant operation, the data acquisition can be performed with the plant at steady state, gradual coast down, or during start-up conditions.

Under some circumstances sensors connected to inactive processes may also be tested by disconnecting them from the process and subjecting them to simulated process signals which contain electronically produced noise.

NAR2201: PROCEDURE FOR PERFORMING DYNAMIC FAILURE MODE ASSESSMENT USING NOISE ANALYSIS

This procedure provides general guidelines fo r performing dynamic failure mode assessment using the noise analysis method. It is not a Vogtle -specific document, so it does not provide any actual Vogtle noise data or analyses results.

Package: ML23081A059 Audit Summary: ML23080A281 Audit Plan: ML23011A274 OFFICE NRR/DORL/LPLII-1/PM NRR/DORL/LPLII-1 /LA NRR/DSS/STSB/BC NAME JLamb KGoldstein VCusumano DATE 03/21/2023 03/22/2023 03/25/2023 OFFICE NRR/DEX/EICB/BC NRR/DORL/LPII-1/BC NRR/DORL/LPII-1/PM NAME MWaters MMarkley JLamb DATE 03/26/2023 03/27/2023 03/27/2023