CNL-20-026, Supplement to Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02)

Supplement to Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02)

ML20049H184
Person / Time
Site:	Sequoyah
Issue date:	02/18/2020
From:	Polickoski J Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-20-026, EPID L-2020-LLA-0004
Download: ML20049H184 (3)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-20-026 February 18, 2020 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Renewed Facility License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328

Subject:

Supplement to Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, (TS-19-02) (EPID L-2020-LLA-0004)

References:

1. TVA Letter to NRC, CNL-19-066, "Application to Revise Sequoyah Nuclear Plant Units 1 and 2 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis (TS-19-02), dated January 14, 2020 (ML20016A396 and ML20016A397)

2. NRC Electronic Mail to TVA, SQN Hydrologic Analysis LAR Acceptance Review - L-2020-LLA-0004, dated February 13, 2020 (ML20049A032)

In Reference 1, Tennessee Valley Authority (TVA) submitted a request for an amendment to Renewed Facility Operating License Nos. DPR-77 and DPR-79 for Sequoyah Nuclear Plant (SQN) Units 1 and 2, respectively. This license amendment request (LAR) revises the SQN Units 1 and 2, Updated Final Safety Analysis Report (UFSAR) to reflect the results from the new hydrologic analysis. TVA determined that the proposed changes to the SQN UFSAR require prior Nuclear Regulatory Commission (NRC) approval.

In Reference 2, NRC submitted a request for information to support the NRC acceptance review of the LAR.

Below is the list of the NRC comments and TVAs response:

NRC Comment 1 Information demonstrating that the dedication of the ArcGIS, QGIS, and PMP Evaluation Tools is conducted in accordance with the requirements of 10 CFR Part 21 under either TVAs QA program or a third-partys QA program that is Appendix B to 10 CFR Part 50 compliant.

U.S. Nuclear Regulatory Commission CNL-20-026 Page 2 February 18, 2020 TVA Response The following information supplements the description of the Topical Report Probable Maximum Precipitation (PMP) Evaluation Tool setup in Attachment A to Enclosures 1 and 5 of Reference 1.

The dedication of the PMP Evaluation Tool was performed under the Barge Design Solutions (Barge) Nuclear Quality Assurance (QA) program that complies with 10 CFR 21, 10 CFR 50, Appendix B, ASME NQA-1-2008/2009 Addenda, and Regulatory Guide 1.28, Revision 4. The Barge QA program has been audited and accepted by TVA and is on the TVA Acceptable Supplier List (ASL). The software dedication report (SDR) for the PMP Evaluation Tool, including the use of associated Python scripts, describes the dedication of the PMP Evaluation Tool.

While the ArcGIS and QGIS evaluation tools were not dedicated, the calculations performed using these tools were checked by either hand calculations or using alternative software in accordance with Barge procedures for design calculations and computer program applications, under the Barge QA program, which complies with NQA-1 Part II Subpart 2.7 Paragraph 202 and is consistent with similar TVA process control procedures under the TVA QA Program. The ArcGIS software functions that are outside of the functions included in the PMP Evaluation Tool SDR, as noted above, were checked using QGIS as the alternate software in accordance with NQA-1 Part II Subpart 2.7 Paragraph 202 under the Barge QA Program. Additional information is provided in the Gridded PMP Development calculation and the SDR, which are available for NRC review.

NRC Comment 2 Information stating that the Microsoft Excel workbook template and the Python scripts for GIS processing of gridded precipitation data were developed under TVAs QA program.

TVA Response As noted in the response to NRC Comment 1, the PMP Evaluation Tool includes the use of associated Python scripts. Therefore, the response to NRC comment 1, regarding the development of the PMP Evaluation Tool under the Barge QA program, also applies to the Python scripts for GIS processing of gridded precipitation data that were used within the PMP Evaluation Tool.

There are portions of the Python scripting that were outside of the PMP Evaluation Tool, but inside a GIS software. While the Microsoft Excel workbook and those portions of the Python scripting that were outside of the PMP Evaluation Tool were not dedicated, their associated calculations were checked by either hand calculations or using alternative software as discussed in the response to NRC Comment 1. Additional information is provided in the Gridded PMP Development calculation and the SDR, which are available for NRC review.

U.S. Nuclear Regulatory Commission CNL-20-026 Page 3 February 18, 2020 This letter does not change the no significant hazard considerations nor the environmental considerations contained in Reference 1. Additionally, in accordance with 10 CFR 50.91(b)(1),

WA is sending a copy of this letter and the enclosure to the Tennessee Department of Environment and Conservation.

Please address any questions regarding this request to Kimberly D. Hulvey, Fleet Licensing Manager, at 423-751-3275. There are no new regulatory commitments contained in this submittal.

I declare under penalty of perjury that the foregoing is true and correct. Executed on this 181h day of February 2020.

Respectfully,

1. Polickoski Director, Nuclear Regulatory Affairs cc:

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Sequoyah Nuclear Plant, Units I and 2 NRC Project Manager - Sequoyah Nuclear Plant Director, Division of Radiological Health

- Tennessee State Department of Environment and Conservation