CNL-22-034, Second Supplement to License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b (SQN-TS-20-03)

Second Supplement to License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b (SQN-TS-20-03)

ML22133A238
Person / Time
Site:	Sequoyah
Issue date:	05/13/2022
From:	Polickoski J Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-22-034, EPID L-2021-LLA-0145, SQN-TS-20-03
Download: ML22133A238 (5)

Text

1101 Market Street, Chattanooga, Tennessee 37402 CNL-22-034 May 13, 2022 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 Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328

Subject:

Second Supplement to License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b (SQN-TS-20-03) EPID L-2021-LLA-0145

References:

1. TVA Letter to NRC, CNL-21-026, License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times---RITSTF Initiative 4b (SQN-TS-20-03), dated August 5, 2021 (ML21217A174)

2. TVA Letter to NRC, CNL-22-023, Supplement to License Amendment Request to Revise Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b (SQN-TS-20-03)

EPID L-2021-LLA-0145, dated April 28, 2022 (ML22118A496)

By letter dated August 5, 2021 (Reference 1), Tennessee Valley Authority (TVA) requested an amendment to the Sequoyah Nuclear Plant (SQN), Units 1 and 2 Renewed Facility Operating License. The proposed amendment would modify Technical Specifications (TS) requirements to permit the use of Risk-Informed Completion Times (RICT) in accordance with Technical Specifications Task Force (TSTF)-505-A, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF [Risk-Informed TSTF] Initiative 4b.

U.S. Nuclear Regulatory Commission CNL-22-034 Page 2 May 13, 2022 In the Reference 1 license amendment request (LAR), TVA made the following regulatory commitment due May 15, 2022:

TVA will supplement this application to either:

1) Provide confirmation from the revised SQN warning time analysis that the External Flooding hazard can be screened out using screening criterion C5.

OR

2) Propose a License Condition requiring confirmation from the revised SQN warning time analysis that the External Flooding hazard can be screened out using screening criterion C5 (or using the criteria of Section 6-2-3 of American Society of Mechanical Engineers/American Nuclear Society RA-Sa-2009 if External Flooding cannot be screened as a slow-moving event) prior to use of the RICT Program.

The External Flooding early warning time reanalysis has been completed and is bounded by the existing early warning time of 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br />, as described in Enclosure 4 to the Reference 1 LAR, that provides adequate time to prepare the plant for an external flood. Therefore, TVA concludes that the timing available to exceed plant grade represents a slow-moving event that meets the criteria for C5, and that there is sufficient time to provide an adequate site response.

Accordingly, this commitment is closed.

In Enclosure 2 to Reference 2, TVA provided additional clarifying detail to the Reference 1 LAR Table E1-1 entry for TS Condition 3.8.1.A, Columns 3 and 6. These clarifications were made at Nuclear Regulatory Commission (NRC) staff request. For consistency, these clarifications are also applicable to the Table E1-1 entry for TS Condition 3.8.1.D and are provided in the Attachment to this letter.

TVA has reviewed the information supporting the no significant hazards consideration and the environmental consideration that was previously provided to the NRC in the referenced LAR.

The additional information provided in this LAR supplement does not impact the conclusion that the proposed license amendment does not involve a significant hazards consideration. The additional information also does not impact the conclusion that there is no need for an environmental assessment to be prepared in support of the proposed amendment.

There are no new regulatory commitments contained in this submittal.

In accordance with Title 10 of the Code of Federal Regulations 50.91, Notice for Public Comment; State Consultation, a copy of this supplement is being provided to the Tennessee Department of Environment and Conservation.

Please address any questions regarding this submittal to Stuart L. Rymer, Senior Manager, Fleet Licensing, at slrymer@tva.gov.

U.S. Nuclear Regulatory Commission CNL-22-034 Page 3 May 13, 2022 I declare under penalty of perjury that the foregoing is true and correct. Executed on this 13th day of May 2022.

Respectfully, Digitally signed by Carla Edmondson Date: 2022.05.13 16:04:38 -04'00' James T. Polickoski Director, Nuclear Regulatory Affairs Attachment Modifications to the License Amendment Request cc (w/ Attachment):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Sequoyah Nuclear Plant NRC Project Manager - Sequoyah Nuclear Plant Director, Division of Radiological Health - Tennessee State Department of Environment and Conservation

Attachment Modifications to the License Amendment Request (1 Page)

CNL-22-034

Attachment Table E1-1: In Scope TS/LCO Conditions to Corresponding PRA Functions SSCs Covered by SSCs Function TS TS Condition TS LCO Modeled in Required by TS Design Success PRA Success Condition Description Condition PRA? LCO Condition Criteria Criteria Other Comments 3.8.1.D AC Sources - Two qualified Yes Provide power One qualified The 6900V With both offsite circuits Operating - circuits between from offsite circuit between the Shutdown inoperable, sufficient Two offsite the offsite transmission offsite transmission Boards have onsite AC sources are circuits transmission network to onsite network and the been modeled available to maintain the inoperable network and the Class 1 buses onsite 1E AC for fast transfer unit in a safe shutdown onsite 1E AC Electrical Power when aligned to condition in the event of a Electrical Power Distribution system either alternate design basis accident or Distribution or normal to transient.

System. onsite power (DGs) upon a loss of offsite power.

Emergency Power (DGs),

Normal or Alternate Supplies, Crosstie Power, and FLEX are all credited in model CNL-21-026 E1-21 of 3