ML20261H418

NRR E-mail Capture - Sequoyah Nuclear Plant, Units 1 and 2 - Audit Plan and Setup of Online Reference Portal

ML20261H418
Person / Time
Site:	Sequoyah
Issue date:	09/14/2020
From:	Michael Wentzel NRC/NRR/DORL/LPL2-2
To:	Taylor A Tennessee Valley Authority
References
L-2020-LLA-0004
Download: ML20261H418 (7)

Text

From: Wentzel, Michael Sent: Monday, September 14, 2020 3:26 PM To: Taylor, Andrew Charles Cc: Wells, Russell Douglas

Subject:

Sequoyah Nuclear Plant, Units 1 and 2 - Audit Plan and Setup of Online Reference Portal (EPID L-2020-LLA-0004)

Attachments: REDACTED - Sequoyah Nuclear Plant, Units 1 and 2 - Plan for Audit of Information in Support of LAR to Revise UFSAR Hydrologic Analysis (L-2020-LLA-0004).pdf

Dear Mr. Taylor:

By application dated January 14, 2020, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20016A396); as supplemented by letters dated February 18, May 14, and August 12, 2020 (ADAMS Accession Nos. ML20049H184, ML20135H067, and ML20225A170, respectively); the Tennessee Valley Authority (TVA), submitted a license amendment request to revise the Sequoyah Nuclear Plant, Units 1 and 2, Updated Final Safety Analysis Report hydrologic analysis.

To improve the efficiency of the U.S. Nuclear Regulatory Commission (NRC) staffs review, TVAs representatives and the NRC staff have discussed the use of an audit using an online reference portal that would allow the NRC staff limited, read-only access to the information identified in Section IV of the attached audit plan. The NRC staff plans to conduct a desk audit to review the documentation provided on the portal. The online reference portal would allow the NRC staff to audit internal licensee information to confirm that the information support statements made in the license amendment request and to determine whether the information included in the documents is necessary to reach a safety conclusion on the application. The audit information the NRC staff determines to be necessary to support the development of the NRC staffs safety evaluation will be requested to be formally submitted on the docket. The audit may also include interactions (e.g. teleconferences or webinars) on a mutually agreeable schedule sufficient to understand or resolve issues associated with the information made available on the online reference portal.

Use of the online reference portal is acceptable, as long as the following conditions are met:

• The online reference portal will be password-protected and passwords will be assigned to those directly involved in the review on a need-to-know basis;

• The online reference portal will be sufficiently secure to prevent NRC staff from printing, saving, or downloading any documents; and

• Conditions of use of the online reference portal will be displayed on the login screen and will require concurrence by each user.

These conditions associated with the online reference portal must be maintained throughout the duration of the audit process.

The NRC staff would like to request that the portal be populated with the information identified in Section IV of the attached audit plan. The NRC staff may request additional documents during the review, which will be transmitted to you via email.

The NRC staffs audit plan contains information that has been designated as Critical Energy Infrastructure Information and Security Related Information. The redacted version of the audit plan is attached. The version containing Critical Energy Infrastructure Information and Security Related Information will be transmitted to you separately via an appropriate mechanism.

If you have any questions, please contact me at (301) 415 6459 or michael.wentzel@nrc.gov.

Sincerely, Michael J. Wentzel, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Hearing Identifier: NRR_DRMA Email Number: 783 Mail Envelope Properties (MN2PR09MB586790B52A0F0CB5EA34BCA0E7230)

Subject:

Sequoyah Nuclear Plant, Units 1 and 2 - Audit Plan and Setup of Online Reference Portal (EPID L-2020-LLA-0004)

Sent Date: 9/14/2020 3:26:23 PM Received Date: 9/14/2020 3:26:23 PM From: Wentzel, Michael Created By: Michael.Wentzel@nrc.gov Recipients:

"Wells, Russell Douglas" <rdwells0@tva.gov>

Tracking Status: None "Taylor, Andrew Charles" <actaylor@tva.gov>

Tracking Status: None Post Office: MN2PR09MB5867.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 3220 9/14/2020 3:26:23 PM REDACTED - Sequoyah Nuclear Plant, Units 1 and 2 - Plan for Audit of Information in Support of LAR to Revise UFSAR Hydrologic Analysis (L-2020-LLA-0004).pdf 80576 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Official Use Only Security Related Information CEII DO NOT RELEASE AUDIT PLAN REGARDING LICENSE AMENDMENT REQUEST TO REVISE UPDATED FINAL SAFETY ANALYSIS REPORT HYDROLOGIC ANALYSIS TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 I. BACKGROUND By application dated January 14, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20014353A016); as supplemented by letters dated February 18 and May 14 , 2020 (ADAMS Accession Nos. ML20049H184 and ML20135H067, respectively); the Tennessee Valley Authority (TVA; the licensee) submitted a license amendment request (LAR) for Sequoyah Nuclear Plant (Sequoyah), Units 1 and 2. The proposed amendments would revise the Sequoyah, Units 1 and 2, Updated Final Safety Analysis Report (UFSAR) to reflect the results from new hydrologic analysis performed by the licensee.

The application references several analyses or documents that are not provided as part of the application or are not provided in the reference section. In order to confirm that the analyses and references support the requested licensing action, the staff of the U.S. Nuclear Regulatory Commission (NRC) plan to perform an audit of the listed documents in the Information Request section below. The NRC staff is continuing to review other aspects of the licensees submittal and may identify the need for additional audit subjects by separate correspondence.

II. REGULATORY AUDIT BASES An audit was determined to be the most efficient approach toward a timely resolution of questions associated with this LAR review, because the NRC staff will have an opportunity to minimize the potential for further rounds of RAIs and ensure no unnecessary burden will be imposed by requiring the licensee to address issues that are no longer necessary to make a safety determination. The NRC staff is requesting an initial set of internal licensee information to be reviewed by the staff using an online reference portal. Upon completion of this audit, the NRC staff is expected to achieve the following.

1. Confirm internal licensee information which supports statements made in the LAR.

2. Determine whether the information included in the documents is necessary to be submitted to support a safety conclusion.

The audit information the NRC staff determines to be necessary to support the development of the NRC staffs safety evaluation will be requested to be submitted on the docket.

Enclosure Official Use Only Security Related Information CEII DO NOT RELEASE

Official Use Only Security Related Information CEII DO NOT RELEASE III. REGULATORY AUDIT SCOPE AND METHODOLOGY The audit is being conducted to confirm that the analyses and references identified below support the requested licensing action. The regulatory audit will address the items in the regulatory audit bases section. The audit will be conducted as a desk audit to review information made available on an online reference portal. The specific areas of focus for the regulatory audit are identified in the information request section, below.

IV. INFORMATION REQUEST Please provide the following information for the NRC staff to audit:

Information Request (IR) 2.4-1: Calculation Packages and Documentation Sections 2.4.2, Floods, and 2.4.3, PMF on Streams and Rivers of the UFSAR enclosed in the LAR present the revised flood hazard estimations at the plant site due to Local Intense Precipitation and riverine floods, respectively. Standard Review Plan (SRP) Sections 2.4.2 and 2.4.3 (ADAMS Accession Nos. ML070100647 and ML070730405, respectively) and Regulatory Guide (RG) 1.59, Revision 2, Design Basis Floods for Nuclear Power Plants (ADAMS Accession No. ML003740388), provide guidelines for estimating these flood causing mechanisms. After reviewing the submitted LAR and enclosed documents, the NRC staff determined that it needs to review additional detailed information related to estimating the flood hazards to support its independent verification of the licensees proposed change. Therefore, the NRC staff requests the following calculation packages and documentation be provided, as referenced in LAR Enclosure 4:

1. Local Intense Precipitation (LIP) Documentation

a. LAR Enclosure 4 Reference [54] Sequoyah Local Intense Precipitation Evaluation-SAR Design Basis (Case 1) and Flood Hazard Re-evaluation Report (Case 2),

Calculation CDQ0000002013000057, Revision 4.

b. Documentation describing the locations and modeling representations of vehicle barrier systems located within the plant site (if not already documented in Reference [54]).

c. Documentation describing the modeling representations of building roofs and associated discharge to the ground surface (if not already documented in Reference [54]).

d. Electronic version of LAR Enclosure 3, Figure 2.4.3-19 (as referenced in LAR Enclosure 4, Section 2.4.2.3).

2. Probable Maximum Flood (PMF) Documentation

a. LAR Enclosure 4 Reference [16] Areal Application of PMP Event Data for the Tennessee River Model above Wheeler Dam.

Official Use Only Security Related Information CEII DO NOT RELEASE

Official Use Only Security Related Information CEII DO NOT RELEASE

b. LAR Enclosure 4 Reference [23] Computer-Determined Unit Hydrographs From Floods.

c. LAR Enclosure 4 Reference [55] Chickamauga Dam (CHH) Probable Maximum Flood Analysis, Calculation CDQ0000002017000059, Revision 0.

d. Documentation of methodology, including dam failure parameters, used to simulate controlling scenario for PMF with hydrologic dam failures (e.g. Enclosure 4, References [30] through [35], [44] through [46], and [60] through [61], as relevant).

3. Seismic Dam Failure Documentation

a. LAR Enclosure 4 Reference [57] Seismic Dam Failure Combined with Rainfall Event Simulations, Calculation CDQ0000002014000024, Revision 5.

b. Site response inputs and results as well as 10,000-year response spectra (tables, if available) for the following four dams:

x (( ))

x (( ))

x (( ))

x (( ))

c. Documentation of TVA stability analyses for the (( )) critical dams above

(( )) dam that were assumed to fail under the controlling PMP storm event, including headwater elevation associated with assumed dam failure conditions (as referenced in LAR Enclosure 4, Section 2.4.4.1). The (( )) critical dams are:

x (( ))

x (( ))

x (( ))

x (( ))

x (( ))

x (( ))

d. Documentation of methodology, including dam failure parameters, used to simulate controlling scenario for seismic dam failures.

Official Use Only Security Related Information CEII DO NOT RELEASE

Official Use Only Security Related Information CEII DO NOT RELEASE

4. Wind Wave Activity Documentation

a. LAR Enclosure 4 Reference [56] Wind Waves for Combined Effect Floods, Calculation CDQ0000002017000059, Revision 0.

IV. AUDIT TEAM Key licensee personnel involved in the development of the LAR should be made available for interactions on a mutually agreeable schedule to respond to any questions from the NRC staff.

Team Member Title Division Area of Responsibility Michael Wentzel Project Manager NRR/DORL/LPL2 Project Management Hosung Ahn Hydrologist NRR/DEX/EXHB Technical Review Ken See Senior Hydrologist NRR/DEX/EXHB Technical Review Kevin Quinlan Meteorologist NRR/DEX/EXHB Technical Review David Heeszel Seismologist NRR/DEX/EXHB Technical Review Scott DeNeale Water Resource Oak Ridge National Technical Review Engineer Laboratory (ORNL)

Shih-Chieh Kao Hydrologist ORNL Technical Review Sudershan Hydrologist ORNL Technical Review Gangrade Kevin Stewart Water Resource ORNL Technical Review Engineer V. LOGISTICS The audit will be started once an electronic portal is set up and the documentation is made available to the NRC staff. The initial desk audit will be conducted over several weeks. The licensee will be kept informed on a regular basis during periodic discussions with the project manager regarding the progress. The audit may include interactions (e.g. teleconferences or webinars) on a mutually agreeable schedule sufficient to understand or resolve issues associated with the information made available.

VI. DELIVERABLES The NRC team will develop an audit summary report to convey the results. The report will be placed in ADAMS within 90 days of the completion of the final audit session. The audit information the NRC staff determines to be necessary to support the development of the NRC staffs safety evaluation will be requested to be submitted on the docket.

Official Use Only Security Related Information CEII DO NOT RELEASE