ML15278A052

Staff Review of Interim Evaluation Associated with Reevaluated Seismic Hazard Implementing Near-Term Task Force Recommendation 2.1 (TAC Nos. MF5267 and MF5268)

ML15278A052
Person / Time
Site:	Sequoyah
Issue date:	10/14/2015
From:	Nicholas Difrancesco Containment and Balance of Plant Branch
To:	James Shea Tennessee Valley Authority
Wyman S, 415-3041, O13C05M
References
TAC MF5267, TAC MF5268
Download: ML15278A052 (2)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 14, 2015 Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 1101 Market Street, LP 3R-C Chattanooga, TN 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - STAFF REVIEW OF INTERIM EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1 (TAC NOS. MF5267 AND MF5268)

Dear Mr. Shea:

By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information pursuant to Title 10 of the Code of Federal Regulations Part 50, Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The request was issued as part of implementing lessons-learned from the accident at the Fukushima Dai-ichi nuclear power plant. to the 50.54(f) letter requested that licensees reevaluate seismic hazards at their sites using present-day methodologies and guidance. Enclosure 1, Item 6, of the 50.54(f) letter requested that licensees identify "interim evaluation and actions taken or planned to address the higher seismic hazard relative to the design basis as appropriate prior to completion of the

[seismic] risk evaluation." In addition to the interim evaluation provided in the March 2014 Seismic Screening and Hazard report, the licensees for the Central and Eastern United States committed to providing the Expedited Seismic Evaluation Process (ESEP) report, an interim evaluation, by December 31, 2014.

By letter dated December 22, 2014 1 , Tennessee Valley Authority (TVA, the licensee), provided its ESEP report in a response to Enclosure 1, Item (6) of the 50.54(f) letter, for the Sequoyah Nuclear Plant, Units 1 and 2 (Sequoyah). The NRC staff assessed the licensee's implementation of the ESEP guidance through the completion of a reviewer checklist 2 . In support of NRC staff questions, TVA provided responses dated June 12, 2015 3 , clarifying submittal information. Based on the NRC staff review of the ESEP report and responses to the staff's questions, the NRC staff concludes that the licensee's ;mplementation of the interim evaluation meets the intent of the guidance.

The staff concludes that, through the implementation of the ESEP guidance, the licensee identified and evaluated the seismic capacity of certain key installed mitigating strategies 1 The December 22, 2014, letter can be found under ADAMS Accession No. ML14365A055.

2 The Sequoyah ESEP NRC review checklist can be found under ADAMS Accession No. ML15272A422.

3 The TVA response to NRC staff questions can be found ADAMS Accession No. ML15239A287.

J. Shea equipment that is used for core cooling and containment functions to cope with scenarios that involve a loss of all alternating current power and loss of access to the ultimate heat sink to withstand a seismic event two times the safe shutdown earthquake for Sequoyah. The licensee's ESEP assessment provides additional assurance which supports continued plant safety while the longer-term seismic evaluation is completed to support regulatory decision making. The NRG staff concludes that the licensee responded appropriately to Enclosure 1, Item (6) of the 50.54(f) letter. Application of this review is limited to the interim evaluation as part of the Recommendation 2.1 seismic review.

The NRG staff notes that Enclosure 2 of the December 22, 2014, letter contains Regulatory Commitments to complete the identified evaluations and any necessary modifications for Unit 1 no later than the end of the second planned Unit 1 refueling outage after December 31, 2014, modify the Unit 2 Turbine Driven Auxiliary Feed Pump Control Panel 2-L-381 anchorage no later than the end of the Unit 2, Cycle 20 refueling outage and submit a letter to NRG summarizing the high confidence of low probability of failure results of Commitment 1 and confirming implementation of the plant modifications associated with Commitment 2 within 60-days following completion of ESEP activities.

If you have any questions, please contact me at (301) 415-1115 or via e-mail at Nicholas.DiFrancesco@nrc.gov.

Sincerely, Nicholas DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328 cc: Distribution via Listserv

J. Shea equipment that is used for core cooling and containment functions to cope with scenarios that involve a loss of all alternating current power and loss of access to the ultimate heat sink to withstand a seismic event two times the safe shutdown earthquake for Sequoyah. The licensee's ESEP assessment provides additional assurance which supports continued plant safety while the longer-term seismic evaluation is completed to support regulatory decision making. The NRC staff concludes that the licensee responded appropriately to Enclosure 1, Item (6) of the 50.54(f) letter. Application of this review is limited to the interim evaluation as part of the Recommendation 2.1 seismic review.

The NRC staff notes that Enclosure 2 of the December 22, 2014, letter contains Regulatory Commitments to complete the identified evaluations and any necessary modifications for Unit 1 no later than the end of the second planned Unit 1 refueling outage after December 31, 2014, modify the Unit 2 Turbine Driven Auxiliary Feed Pump Control Panel 2-L-381 anchorage no later than the end of the Unit 2, Cycle 20 refueling outage and submit a letter to NRC summarizing the high confidence of low probability of failure results of Commitment 1 and confirming implementation of the plant modifications associated with Commitment 2 within 60-days following completion of ESEP activities.

If you have any questions, please contact me at (301) 415-1115 or via e-mail at Nicholas.DiFrancesco@nrc.gov.

Sincerely, IRA/

Nicholas DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328 cc: Distribution via Listserv DISTRIBUTION:

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• via concurrence e-mail OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA DSENRGS2 NAME SWyman Slent DJackson*

DATE 10/1/2015 10/9/2015 9/8/2015 OFFICE NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME MShams NDiFrancesco DATE 10/14/2015 10/14/2015 OFFICIAL RECORD COPY