ML25357A113

Regulatory Audit Summary in Support of LAR to Use Online Monitoring Methodology(NON-PROPRIETARY)

ML25357A113
Person / Time
Site:	Grand Gulf, Arkansas Nuclear, River Bend, Waterford
Issue date:	01/06/2026
From:	Michael Mahoney Plant Licensing Branch IV
To:	Gustafson O Entergy Services
References
EPID L-2024-LLA-0160
Download: ML25357A113 (0)

Text

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION January 6, 2026 Otto Gustafson Vice President, Regulatory Assurance Entergy Services, LLC M-ECH-29 1340 Echelon Parkway Jackson, MS 39213

SUBJECT:

ARKANSAS NUCLEAR ONE, UNITS 1 AND 2; GRAND GULF NUCLEAR STATION, UNIT 1; RIVER BEND STATION, UNIT 1; AND WATERFORD STEAM ELECTRIC STATION, UNIT 3 - REGULATORY AUDIT

SUMMARY

IN SUPPORT OF LICENSE AMENDMENT REQUEST TO USE ONLINE MONITORING METHODOLOGY (EPID L-2024-LLA-0160)

Dear Mr. Gustafson:

By letter dated December 4, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24339B304), Entergy Operations, Inc. (Entergy, the licensee) submitted a license amendment request (LAR) to revise the technical specifications (TSs) for Arkansas Nuclear One, Units 1 and 2; Grand Gulf Nuclear Station, Unit 1; River Bend Station, Unit 1; and Waterford Steam Electric Station, Unit 3.

The proposed changes would revise the Definitions TS section and add a new Online Monitoring Program to the Administrative Controls TS section. Entergy proposes to use online monitoring (OLM) methodology as the technical bases to switch from time-based surveillance frequency for channel calibrations to a condition-based calibration frequency based on OLM results. Entergy stated that the proposed change is based on the U.S. Nuclear Regulatory Commission (NRC)-approved topical report AMS-TR-0720R2-A, Online Methodology Technology to Extend Calibration Intervals for Nuclear Plant Pressure Transmitters (ML21235A493).

The NRC staff reviewed Entergys LAR and determined that a regulatory audit would assist in the timely completion of the LAR review. The NRC staff conducted a regulatory audit that consisted of a remote audit, with a call with the licensee on April 22, 2025. The audit plan was issued on February 26, 2025 (ML25056A269), with a supplemental audit item issued on February 28, 2025 (ML25351A239). The audit plan included a list of items to be provided on an electronic portal. The staff audited these documents and held discussions with members of Entergy on the LAR relevant to the NRC staffs review. As a result of the audit, no requests for additional information were issued. A summary of the audit is enclosed.

to this letter contains proprietary information. When separated from enclosure 1, this document is DECONTROLLED.

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION The NRC staff has determined that enclosure 1 contains proprietary information pursuant to Title 10 of the Code of Federal Regulations Section 2.390, Public inspections, exemptions, request for withholding. Proprietary text will be contained within double brackets (( this is proprietary text )). Accordingly, the staff has prepared a redacted version, which is provided as enclosure 2.

If you have questions, please contact me at 301-415-3867 or via email at Michael.Mahoney@nrc.gov.

Sincerely,

/RA/

Michael Mahoney, Sr. Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-313, 50-368, 50-416, 50-458, and 50-382

Enclosures:

1. Proprietary Audit Summary

2. Non-Proprietary Audit Summary cc: Listserv w/o enclosure 1 to this letter contains proprietary information. When separated from enclosure 1, this document is DECONTROLLED.

OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION ENCLOSURE 1 (PROPRIETARY)

ARKANSAS NUCLEAR ONE, UNITS 1 AND 2 DOCKET NOS. 50-313 AND 50-368 GRAND GULF NUCLEAR STATION, UNIT 1 DOCKET NO. 50-416 RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458 WATERFORD STEAM ELECTRIC STATION, UNIT 3 DOCKET NO. 50-382 REGULATORY AUDIT

SUMMARY

RELATED TO LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS TO USE ONLINE MONITORING This document contains proprietary information pursuant to Title 10 of the Code of Federal Regulations Section 2.390.

Proprietary information is identified by bold text enclosed within double brackets, as shown here: (( example proprietary text )).

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION ENCLOSURE 2 (NON-PROPRIETARY)

ARKANSAS NUCLEAR ONE, UNITS 1 AND 2 DOCKET NOS. 50-313 AND 50-368 GRAND GULF NUCLEAR STATION, UNIT 1 DOCKET NO. 50-416 RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458 WATERFORD STEAM ELECTRIC STATION, UNIT 3 DOCKET NO. 50-382 REGULATORY AUDIT

SUMMARY

RELATED TO LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS TO USE ONLINE MONITORING Proprietary information pursuant to Title 10 of the Code of Federal Regulations Section 2.390 has been redacted from this document.

Redacted information is identified by blank space enclosed within (( double brackets )).

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION REGULATORY AUDIT

SUMMARY

RELATED TO LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS TO USE ONLINE MONITORING ENTERGY OPERATIONS, INC.

ARKANSAS NUCLEAR ONE, UNITS 1 AND 2 DOCKET NOS. 50-313 AND 50-368 GRAND GULF NUCLEAR STATION, UNIT 1 DOCKET NO. 50-416 RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458 WATERFORD STEAM ELECTRIC STATION, UNIT 3 DOCKET NO. 50-382

1.0 BACKGROUND

A regulatory audit is a planned license or regulation-related activity that includes the examination and evaluation of docketed and non-docketed information. The audit was conducted with the intent to gain understanding, to verify information, and to identify information that will require docketing to support the basis of a licensing or regulatory decision.

By letter dated December 4, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24339B304), Entergy Operations, Inc. (Entergy, the licensee) submitted a license amendment request (LAR) to revise the technical specifications (TSs) for Arkansas Nuclear One (ANO), Units 1 and 2; Grand Gulf Nuclear Station, Unit 1 (Grand Gulf);

River Bend Station, Unit 1 (River Bend); and Waterford Steam Electric Station, Unit 3 (Waterford).

The proposed changes would revise the Definitions TS section and add a new Online Monitoring Program to the Administrative Controls TS section. Entergy proposes to use online monitoring (OLM) methodology as the technical bases to switch from time-based surveillance frequency for channel calibrations to a condition-based calibration frequency based on OLM results. Entergy stated that the proposed change is based on the U.S. Nuclear Regulatory Commission (NRC)-approved topical report AMS-TR-0720R2-A, Online Methodology Technology to Extend Calibration Intervals for Nuclear Plant Pressure Transmitters (ML21235A493).

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION As the NRC staff performed its review of the LAR, it was determined that a regulatory audit would assist in the timely completion of the review. The regulatory audit was performed consistent with NRC Office of Nuclear Reactor Regulation Office Instruction LIC-111, Revision 1, Regulatory Audits, dated October 31, 2019 (ML19226A274).

2.0 AUDIT ACTIVITIES AND OBSERVATIONS The NRC staff conducted a regulatory audit remotely with a call with Entergy on April 22, 2025.

The remote audit was conducted using the Certrec portal. An audit plan was provided to Entergy on February 26, 2025 (ML25056A269), with a supplemental audit item issued on February 28, 2025 (ML25351A239). The list of information uploaded by Entergy in response to the NRC staffs request and examined by the audit team is provided in section 4.0 below. The list of audit questions sent to Entergy is provided in section 5.0 below.

Entergy staff and Analysis and Measurement Services Corporation (AMS) staff supported the audit by providing remote access via Certrec, an internet-based electronic reading room, to requested reports and by making appropriate staff with detailed knowledge of AMS-TR-0720R1 available for discussions with the NRC staff.

Based on the audit activities, the NRC staff determined no additional information is needed on the docket, and the staff can complete its review.

Entergy addressed questions 1-5 listed in section 5.0 Licensee Response:

1. Entergy discussed and provided additional information on how steps in section 11.1.2 of AMS-TR-0720R2-A TR would be followed for the cases of newer transmitters where there was no recent or available data being used for the OLM program. The licensee emphasized and provided additional detail on the implementation and approach for these cases, consistent with the OLM TR.

2. Entergy provided clarification on one of the reports regarding one of the tables provided for this question, in addition to going over the calculations used to populate the information in the associated report.

3. Entergy confirmed for the cases pointed out where justification for OLM inclusion was needed, there are no deviations from the steps provided in Section 11.2 AMS-TR-0720R2-A with no difference from other cases.

4. Entergy clarified how transmitters are being captured in the reports regarding the transmitter model names being used for the proposed OLM program.

5. Entergy demonstrated using the methodology identified in the International Society of Automation (ISA) 67.04.02 Annex H, and the uncertainty terms therein included are accounted for to measure the drift of the instrument channels in the OLM program are smaller than initially provided for. The licensee explained that the originally provided estimates were overly-conservative, going over the calculations demonstrating ISA 67.04.02 Annex H, appearing to be reasonably low enough to reliably monitor the drift of the instrument channels in the OLM program as these approach the established OLM limits.

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION Notes for each of the AMS reports audited are provided below.

AMS Reports ANO2302R0, ANO2307R0, GGN2302R0, RBD2302R0, WAT2302R0 OLM Amenable Transmitters Report for ANO Unit 1, OLM Amenable Transmitters Report for ANO Unit 2, OLM Amenable Transmitters Report for Grand Gulf, OLM Amenable Transmitters Report for River Bend, OLM Amenable Transmitters Report for Waterford respectively.

These reports address steps 1 through 6 of section 11.1.1 of the TR for the transmitters in each of the Nuclear Plants that are included in the OLM program. It identifies groups of pressure, level and flow transmitters for each unit that qualify to be entered into the OLM programs.

AMS Reports ANO2303R0, ANO2308R0, GGN2303R0, RBD2303R0, WAT2303R0,, OLM Analysis Methods and Limits Report for ANO Unit 1, OLM Analysis Methods and Limits Report for ANO Unit 2, OLM Analysis Methods and Limits Report for Grand Gulf, OLM Analysis Methods and Limits Report for River Bend, OLM Analysis Methods and Limits Report for Waterford respectively.

This report addresses steps 7 through 8 of section 11.1.1 of the TR AMS-TR-0720R2-A for the transmitters Entergy plants being proposed in this license amendment request that are being proposed for the OLM program. The NRC staff observed greater values for uncertainties associated with the M&TE in certain configurations and transmitter groups. This led to the conversation related to the recommended practice in relation to uncertainties associated with the plant process computer that is included as part of the proposed M&TE, to account for uncertainties associated with the digital system accuracy term.

AMS Reports ANO2304R0, ANO2309R0, GGN2304R0, RBD2304R0, WAT2304R0, OLM Drift Monitoring Program Report for ANO Unit 1, OLM Drift Monitoring Program Report for ANO Unit 2, OLM Drift Monitoring Program Report for Grand Gulf, OLM Drift Monitoring Program Report for River Bend, OLM Drift Monitoring Program Report for Waterford, respectively.

These documents provide the steps to be followed to implement OLM for transmitter drift monitoring in accordance with TR AMS-TR-0720R2-A for the plants being proposed for OLM.

The steps described in the document are intended to be repeated at each operating cycle to identify the transmitters that should be scheduled for a calibration check. Following the steps in this document will ensure that OLM data is properly acquired, qualified, analyzed, interpreted, reported, and documented.

OLM2201, Procedure for Online Monitoring Data Retrieval This test procedure is for retrieving OLM data from the plant historian using the AMS Bridge software. It provides general steps that are followed when retrieving OLM data, not specific to Entergy plants being proposed.

AMS Procedure OLM2202, Procedure for Performing Online Monitoring Data Qualification and Analysis

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION This procedure outlines the general steps that are followed when performing OLM data analysis of the data being retrieved. It provides general steps that are followed when analyzing OLM data, not specific to Entergy.

AMS Reports ANO2305R0, ANO2310R0, GGN2305R0, RBD2305R0, WAT2305R0, OLM Noise Analysis Program Report for ANO Unit 1, OLM Noise Analysis Program Report for ANO Unit 2, OLM Noise Analysis Program Report for Grand Gulf, OLM Noise Analysis Program Report for River Bend, OLM Noise Analysis Program Report for Waterford, respectively.

These reports provide the steps that must be followed to implement noise analysis for assessment of transmitter dynamic failure modes. The steps described are to be repeated at each operating cycle at ANO1, ANO2, Grand Gulf, River Bend, Waterford for a minimum of one transmitter on a staggered basis in each redundant group which has a response time requirement as outlined to identify its dynamic failure modes. The steps outlined in this document ensure that proper noise analysis equipment is used, and data is properly acquired, qualified, analyzed, interpreted, reported, and documented.

AMS Procedure 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. This procedure is used for on-line data acquisition from a wide variety of sensors and systems while the plant is operating at any mode that provides adequate signal amplitudes for analysis.

AMS Procedure NAR2201, Procedure for Performing Dynamic Failure Mode Assessment Using Noise Analysis This procedure provides general guidelines for performing dynamic failure mode assessment using the noise analysis method. This procedure is not specific to Entergy.

3.0 AUDIT PARTICIPANTS NRC Entergy Gilberto Blas Philip Couture III, Fred OBrien Daniel Bourgoin Hanna McLatchie Amy Madeiras Michael Mahoney Jonathan Perrine AMS Greg Morton Brent Shumaker Caleb M. Crosby 4.0 DOCUMENTS PROVIDED IN ELECTRONIC READING ROOM

1.

ANO2302R0, OLM Amenable Transmitters Report for ANO Unit 1

2.

ANO2307R0, OLM Amenable Transmitters Report for ANO Unit 2

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION

3.

GGN2302R0, OLM Amenable Transmitters Report for Grand Gulf

4.

RBD2302R0, OLM Amenable Transmitters Report for River Bend

5.

WAT2302R0, OLM Amenable Transmitters Report for Waterford

6.

AMS [Analysis and Measurement Services Corporation] Report ANO2303R0, OLM Analysis Methods and Limits Report for ANO Unit 1

7.

AMS Report ANO2308R0, OLM Analysis Methods and Limits for Report ANO Unit 2

8.

AMS Report GGN2303R0, OLM Analysis Methods and Limits Report for Grand Gulf

9.

AMS Report RBD2303R0, OLM Analysis Methods and Limits Report for River Bend

10.

AMS Report WAT2303R0, OLM Analysis Methods and Limits Report for Waterford

11.

AMS Report ANO2304R0, OLM Drift Monitoring Program Report for ANO Unit 1

12.

AMS Report ANO2309R0, OLM Drift Monitoring Program Report for ANO Unit 2

13.

AMS Report GGN2304R0, OLM Drift Monitoring Program Report for Grand Gulf

14.

AMS Report RBD2304R0, OLM Drift Monitoring Program Report for River Bend

15.

AMS Report WAT2304R0, OLM Drift Monitoring Program Report for Waterford

16.

AMS Procedure OLM2201, Procedure for Online Monitoring Data Retrieval

17.

AMS Procedure OLM2202, Procedure for Performing Online Monitoring Data Qualification and Analysis

18.

AMS Report ANO2305R0, OLM Noise Analysis Program Report for ANO Unit 1

19.

AMS Report ANO2310R0, OLM Noise Analysis Program Report for ANO Unit 2

20.

AMS Report GGN2305R0, OLM Noise Analysis Program Report for Grand Gulf

21.

AMS Report RBD2305R0, OLM Noise Analysis Program Report for River Bend

22.

AMS Report WAT2305R0, OLM Noise Analysis Program Report for Waterford

23.

AMS Procedure NPS1501, Procedure for Noise Data Collection from Plant Sensors

24.

AMS Procedure NAR2201, Procedure for Performing Dynamic Failure Mode Assessment Using Noise Analysis

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION

25.

AMS Report No. ENT2501, AMS Response to Audit Questions, Entergy Fleet License Amendment Request to Use Online Monitoring Methodology, EPID: L-2024-LLA-0160

26.

AMS Report No. ENT2502, AMS Response to Supplemental Question, Entergy Fleet License Amendment Request to Use Online Monitoring Methodology, EPID: L-2024-LLA-0160 5.0 LIST OF AUDIT QUESTIONS

1. ((

))

2. Staff would like to see the entire calculations made to generate the OLM limits for

((

))

3. For OLM cases where justifications are made, are there any deltas for the determination of the OLM limits, ((

)) and identification for calibration?

((

))

4. ((

))

A supplemental question was sent on February 28, 2025 (ML25351A239):

5. Entergy requests to use Measurement and Test Equipment (M&TE), which includes the plant computer, to collect data and check if a transmitter is in need of calibration.

Entergy plans to measure how much each transmitter's readings change over time or drift and compare these to a set Online Monitoring (OLM) limit. For certain cases, the drift being measured is very small. However, the documents referenced in the license amendment request (LAR) state that the uncertainties associated with the proposed M&TE to measure these changes may be large.

Please explain how Entergy has determined that the M&TE being proposed, which includes the plant process computer, is capable of reliably measuring the instrument

OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION channel drift with an accuracy that will not mask the drift being measured given the associated uncertainty in these configurations. For example, describe how the proposed M&TE, inclusive of digital signal conversion and algebraic presentation, is sufficiently accurate to reliably measure the drift in the transmitters included in the OLM program to support the decision making (for example, see International Society of Automation (ISA)

Recommended Practice 67.04.02, Annex H).