CNL-21-048, Hydrologic Engineering Center River Analysis System (HEC-RAS) Project Miilstone Status Update

Hydrologic Engineering Center River Analysis System (HEC-RAS) Project Miilstone Status Update

ML21119A176
Person / Time
Site:	Browns Ferry, Watts Bar, Sequoyah
Issue date:	04/29/2021
From:	Polickoski J Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-21-048
Download: ML21119A176 (3)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-21-048 April 29, 2021 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296 Sequoyah Nuclear Plant, Units 1 and 2 Renewed Facility Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328 Watts Bar Nuclear Plant, Units 1 and 2 Facility Operating License Nos. NPF-90 and NPF-96 NRC Docket Nos. 50-390 and 50-391

Subject:

TENNESSEE VALLEY AUTHORITY - HYDROLOGIC ENGINEERING CENTER RIVER ANALYSIS SYSTEM (HEC-RAS) PROJECT MILESTONE STATUS UPDATE

Reference:

TVA letter to NRC, Tennessee Valley Authority - Hydrologic Engineering Center River Analysis System (HEC-RAS) Project Milestones, dated June 22, 2016 (ML16175A518)

By letter dated June 22, 2016, Tennessee Valley Authority (TVA) provided the Nuclear Regulatory Commission (NRC) with dates for several project deliverables associated with the ongoing Hydrologic Engineering Center River Analysis System (HEC-RAS) external flood modeling project (referenced letter). The HEC-RAS external flood modeling project was the subject of an April 4, 2016, public meeting to discuss technical details and a resolution plan for TVAs HEC-RAS external flood modeling issues. In the referenced letter, TVA committed to provide updates on the status of the specific project deliverables on a six-month frequency.

U.S. Nuclear Regulatory Commission CNL-21-048 Page 2 April 29, 2021 The purpose of this letter is to provide the tenth written update regarding the status of the project milestones consistent with the commitment made in the referenced letter.

No tasks have been completed since the update provided by letter dated October 29, 2020 (ML20304A178). Task 8 is currently projected to be completed in December 2021. The additional time to complete Task 8 is associated with the resolution of a potentially unconservative assumption in one of the analyses supporting the License Amendment Request (LAR). The potentially unconservative assumption was discussed with NRC on October 13, 2020 (ML20293A080).

TABLE 1 PROJECT DELIVERABLE SUBMITTAL MILESTONES (Status Updates Shown in Bold Text)

Submittal Project Deliverable Milestone 1 Browns Ferry Mitigating Strategies Assessment Complete 2 Sequoyah Mitigating Strategies Assessment Complete 3 Watts Bar Mitigating Strategies Assessment Complete 4 Watts Bar Focused Evaluation Complete 5 Sequoyah Focused Evaluation Complete 6 Browns Ferry Focused Evaluation Complete 7 Sequoyah Hydrology License Amendment Request Complete 8 Watts Bar Hydrology License Amendment Request December 2021 The projected milestone for the submittal of the Watts Bar Hydrology LAR will continue to be discussed with the NRC Project Manager.

U.S. Nuclear Regulatory Commission CNL-21-048 Page 3 April 29, 2021 TVA will provide the eleventh status update on these project deliverable submittal milestones by October 31, 2021, consistent with the commitment made in the referenced letter.

There are no new regulatory commitments made in this letter.

If additional information is needed regarding this update, please contact Russell Thompson at (423) 751-2567.

Respectfully, James T. Polickoski Director, Nuclear Regulatory Affairs cc:

NRR Director - NRC Headquarters NRC Regional Administrator - Region II NRC Project Manager - Browns Ferry Nuclear Plant NRC Project Manager - Sequoyah Nuclear Plant NRC Project Manager - Watts Bar Nuclear Plant NRC Senior Resident Inspector - Browns Ferry Nuclear Plant NRC Senior Resident Inspector - Sequoyah Nuclear Plant NRC Senior Resident Inspector - Watts Bar Nuclear Plant