ML15238A429

Staff Review of Interim Evaluation Associated with Reevaluated Seismic Hazard Implementing Near-Term Task Force Recommendation 2.1

ML15238A429
Person / Time
Site:	Calvert Cliffs
Issue date:	09/23/2015
From:	Nicholas Difrancesco Japan Lessons-Learned Division
To:	George Gellrich Exelon Generation Co
Wyman S, NRR/JLD, 415-3041
References
TAC MF5231, TAC MF5232
Download: ML15238A429 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 23, 2015 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Generation 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER 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. MF5231 AND MF5232)

Dear Mr. Hanson:

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 letters dated December 17, 20141, Exelon Generation Company, LLC, previously as Constellation Energy Nuclear Group, LLC (Exelon, the licensee), provided its ESEP report in a response to Enclosure 1, Item (6) of the 50.54(f) letter, for Calvert Cliffs Nuclear Power Plant Units 1 and 2 (Calvert Cliffs). 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, Exelon provided a response dated June 18, 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 implementation of the interim evaluation meets the intent of the guidance.

1 The December 17, 2014, letter can be found under ADAMS Accession No. ML14365A138.

2 The Calvert Cliffs ESEP NRC review checklist can be found under ADAMS Accession No. ML15231A397.

3 The Exelon response to N RC staff questions can be found ADAMS Accession No. ML15218A411.

B. Hanson The NRC staff concludes that, through the implementation of the ESEP guidance, the licensee identified and evaluated the seismic capacity of certain key installed mitigating strategies 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 1.17 times the safe shutdown earthquake for Calvert Cliffs. 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.

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

Sincerely, Nicholas J. DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318 cc: Distribution via Listserv

B. Hanson The NRC staff concludes that, through the implementation of the ESEP guidance, the licensee identified and evaluated the seismic capacity of certain key installed mitigating strategies 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 1.17 times the safe shutdown earthquake for Calvert Cliffs. 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.

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

Sincerely, IRA/

Nicholas J. DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318 cc: Distribution via Listserv DISTRIBUTION:

PUBLIC JLD R/F RidsOeMailCenter RidsNrrPMCalvert Cliffs RidsNrrDorllpl1-1 RidsNrrLASLent RidsRgn1 MailCenter RidsNrrOd DJackson, NRO MShams, NRR NDiFrancesco, NRR ADAMS Accession Number: ML15238A429

• via concurrence e-mail OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA DSEA/RGS2 NAME SWyman Slent DJackson*

DATE 8/27/2015 9/1/2015 8/10/2015 OFFICE NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME MShams NDiFrancesco DATE 9/3/2015 9/15/2015 OFFICIAL RECORD COPY