ML15272A213
| ML15272A213 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/27/2015 |
| From: | Nicholas Difrancesco Japan Lessons-Learned Division |
| To: | Bryan Hanson Exelon Nuclear |
| Wyman, Stephen, NRR/JLD 415-3041 | |
| References | |
| TAC MF5270 | |
| Download: ML15272A213 (3) | |
Text
Mr. Bryan C. Hanson President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 27, 2015
SUBJECT:
THREE MILE ISLAND NUCLEAR STATION, UNIT 1 -STAFF REVIEW OF INTERIM EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTATING NEAR-TERM TASK FORCE RECOMMENDATION 2.1 (TAC NO. MF5270)
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 Fukush;rna 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 17, 20141, Exelon Generation Company. LLC (Exelon, the licensee),
provided its ESEP report in a response to Enclosure 1, Item (6) of the 50.54{f) letter, for Three Mile Island Nuclear Station, Unit 1 (TMI). The NRC staff assessed the licensee's implementation of the ESEP guidance through the completion of a reviewer checklist2. In support of NRC staff questions, Exelon provided a response dated July 30, 20153, 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 m1plementation of the interim evaluation meets the intent of the guidance.
1 The December 17, 2014, letter can be found under ADAMS Accession No. ML14353A194.
2 The TMI ESEP NRC review checklist can be found under ADAMS Accession No. ML15240A213.
3 The Exelon response to NRC staff questions can be found ADAMS Accession No. ML15232A331.
The NRG 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 1.13 times the safe shutdown earthquake for TMI. Consistent with the ESEP guidance the review of key mitigating strategies equipment did not include evaluation of associated structures. Evaluation of structures will occur as part of the staff review under Order EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events." Notwithstanding, 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.
If you have any questions, please contact me at (301) 415-1115 or via e-mail at Nicholas.DiFrancesco@nrc.gov.
Docket No. 50-289 cc: Distribution via Listserv Sincerely,
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Nicholas DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
ML15272A213 OFFICE NRR/JLD/JHMB/PM NAME SWyman DATE 9/28/2015 OFFICE NRR/JLD/JHMB/BC NAME MS hams DATE 10/21/2015 Sincerely, IRA/
Nicholas DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation RidsNrrPMThreeMilelsland Resource RidsNrrLASLent RidsNrrOd MShams, NRR
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