ML15281A029
| ML15281A029 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 10/14/2015 |
| From: | Nicholas Difrancesco Japan Lessons-Learned Division |
| To: | Gardner P Northern States Power Co |
| Wyman S, 415-3041, O-13C05M | |
| References | |
| TAC MF5251 | |
| Download: ML15281A029 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Peter A. Gardner Site Vice President October 14, 2015 Northern States Power Company - Minnesota Monticello Nuclear Generating Plant 2807 West County Road 75 Monticello, MN 55362-9637
SUBJECT:
MONTICELLO NUCLEAR GENERATING PLANT-STAFF REVIEW OF INTERIM EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1 (TAC NO. MF5251)
Dear Mr. Gardner:
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 1 O 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 23, 20141, Northern States Power Company - Minnesota (NSPM, the licensee) doing business as Xcel Energy, provided its ESEP report in a response to Enclosure 1, Item (6) of the 50.54(f) letter, for the Monticello Nuclear Generating Plant (Monticello). 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, Xcel Energy provided responses dated May 22, 2015, and August 13, 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 implementation of the interim evaluation meets the intent of the guidance.
1 The December 23, 2014, letter can be found under ADAMS Accession No. ML14357A280.
2 The Monticello ESEP NRC review checklist can be found under ADAMS Accession No. ML15272A421 3 The Xcel Energy responses to NRC staff questions can be found ADAMS Accession Nos.
ML15142A862 and ML15225A463.
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 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 1.49 times the safe shutdown earthquake for Monticello. The licensee has demonstrated 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 R2.1 Seismic review The NRC staff notes that a summary of regulatory commitments to complete ESEP activites is documented in the response to request for additional information No. 7 in the May 22, 2015, letter. A letter will be provided to the NRC indicating the proposed resolution applicable to each component in Section 8.2 of the Monticello ESEP Report and the expected timeframe for completion of the resolution when this information has been developed. A letter will be provided to the NRC summarizing the High Confidence of Low Probability of Failure results of each component and confirming the resolution of each component. This letter will be sent within 60-days of completion of the resolution activities for the final completed component from Table 7-1 of the May 22, 2015, letter.
If you have any questions, please contact me at (301) 415-1115 or via e-mail at Nicholas DiFrancesco@nrc.gov.
Docket No. 50-263 cc: Distribution via Listserv Sincerely, Nicholas DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
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 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 1.49 times the safe shutdown earthquake for Monticello. The licensee has demonstrated 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 R2.1 Seismic review The NRC staff notes that a summary of regulatory commitments to complete ESEP activites is documented in the response to request for additional information No. 7 in the May 22, 2015, letter. A letter will be provided to the NRC indicating the proposed resolution applicable to each component in Section 8.2 of the Monticello ESEP Report and the expected timeframe for completion of the resolution when this information has been developed. A letter will be provided to the NRC summarizing the High Confidence of Low Probability of Failure results of each component and confirming the resolution of each component. This letter will be sent within 60-days of completion of the resolution activities for the final completed component from Table 7-1 of the May 22, 2015, letter.
If you have any questions, please contact me at (301) 415-1115 or via e-mail at Nicholas DiFrancesco@nrc.gov.
Docket No. 50-263 cc: Distribution via Listserv DISTRIBUTION:
PUBLIC LPL3-1 R/F JLD R/F RidsNrrPMMonticello RidsNrrDorllpl3-1 NDiFrancesco, NRR ADAMS Accession Number: ML15281A029 OFFICE NRR/JLD/JHMB/PM NAME SWyman DATE 10/8/2015 OFFICE NRR/JLD/JHMB/BC NAME MS hams DATE 10/14/2015 Sincerely, IRA/
Nicholas DiFrancesco, Senior Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation RidsN rrLASLent RidsRgn3MailCenter MShams, NRR NRR/JLD/LA Slent 10/9/2015 NRR/JLD/JHMB/PM NDiFrancesco 10/14/2015 RidsNrrOd DJackson, NRO
- via e-mail DSENRGS2/BC DJackson*
9/4/2015 OFFICIAL RECORD COPY