ML16259A362
| ML16259A362 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 09/29/2016 |
| From: | Steve Wyman Japan Lessons-Learned Division |
| To: | Entergy Operations |
| Wyman S, NRR/JLD/JHMB 301-415-3041 | |
| References | |
| Download: ML16259A362 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Vice President, Operations Entergy Operations, Inc.
River Bend Station 5485 U.S. Highway 61 N St. Francisville, LA 70775 September 29, 2016
SUBJECT:
RIVER BEND STATION, UNIT 1 - STAFF REVIEW OF MITIGATION STRATEGIES ASSESSMENT REPORT OF THE IMPACT OF THE REEVALUATED SEISMIC HAZARD DEVELOPED IN RESPONSE TO THE MARCH 12, 2012, 50.54(f) LETTER
Dear Sir or Madam:
The purpose of this letter is to provide the U.S. Nuclear Regulatory Commission's (NRG) assessment of the seismic hazard mitigation strategies assessment (MSA), as described in the August 31, 2016, letter (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML16251A069), submitted by Entergy Operations, Inc. (Entergy, the licensee) for River Bend Station, Unit 1 (River Bend). The MSA confirms that the licensee has adequately addressed the reevaluated seismic hazard within its mitigation strategies for beyond-design-basis external events.
BACKGROUND By letter dated March 12, 2012 (ADAMS Accession No. ML12053A340), the NRG issued a request for information pursuant to Title 10 of the Code of Federal Regulations (10 CFR),
Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The 50.54(f) letter was issued as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 1 to the 50.54(f) letter requested licensees reevaluate the seismic hazard using present-day methodologies and guidance. Concurrent with the reevaluation of seismic hazards, the NRG issued Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML12054A736). The order requires holders of operating power reactor licenses and construction permits issued under 1 O CFR Part 50 to develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment, and spent fuel pool cooling following a beyond-design-basis external event.
By letter dated March 26, 2014 (ADAMS Accession No. ML14091A426), the licensee provided its reevaluated seismic hazard for River Bend in response to the 50.54(f) letter.
On December 10, 2015 (ADAMS Accession No. ML16005A621 ), the Nuclear Energy Institute (NEI) submitted Revision 2 to NEI 12-06, including guidance for MSAs regarding reevaluated hazard information. The NRC subsequently endorsed NEI 12-06, Revision 2, with exceptions, clarifications, and additions, in Japan Lessons-Learned Division (JLD) interim staff guidance (ISG) JLD-ISG-2012-01, Revision 1, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (ADAMS Accession No. ML15357A163).
MITIGATION STRATEGIES ASSESSMENT By letter dated November 3, 2015 (ADAMS Accession No. ML15295A186), the NRC staff documented its review of the licensee's reevaluated seismic hazard, also referred to as the mitigation strategies seismic hazard information. The staff confirmed the licensee's conclusion that the licensee's Ground Motion Response Spectrum (GMRS) for the River Bend site is bounded by the safe shutdown earthquake (SSE) in the 1 to 10 Hertz (Hz) range, but exceeds the SSE in a portion of the frequency range above 10 Hz, meriting a high frequency confirmation. In addition, the staff concluded that the GMRS determined by the licensee adequately characterizes the reevaluated seismic hazard for the River Bend site.
By letter dated December 8, 2015 (ADAMS Accession No. ML16005A088), Entergy submitted a High Frequency Confirmation Report for River Bend. By letter dated February 18, 2016 (ADAMS Accession No. ML15364A544 ), the NRC staff confirmed the River Bend GMRS exceedance above the current design basis has peak spectral accelerations less than 0.2g and met the criterion described in Section 3.1.1, "Low Spectral Acceleration Screening" in Electric Power Research Institute (EPRI) Report 3002004396. The EPRI report concluded, and the staff agreed, that peak accelerations below 0.2g do not represent a significant high frequency concern. Therefore, the methodology used by the licensee is appropriate to disposition the GMRS exceedance above the current design basis.
The licensee stated that the River Bend MSA was performed consistent with NEI 12-06, Revision 2. Appendix H of NEI 12-06, Revision 2, describes acceptable methods for demonstrating that the reevaluated seismic hazard is addressed within the River Bend mitigation strategies for beyond-design-basis external events. The NRC staff confirmed that the licensee's seismic hazard MSA is consistent with the guidance in Appendix H.4.2 of NEI 12-06, Revision 2, as endorsed by JLD-ISG-2012-01, Revision 1. Therefore, the methodology used by the licensee is appropriate to perform an assessment of the mitigation strategies that addresses the reevaluated seismic hazard.
The NRC staff has reviewed the seismic hazard MSA for River Bend. The NRC staff concludes that sufficient information has been provided to demonstrate that the licensee's plans for the development and implementation of guidance and strategies under Order EA-12-049 appropriately address the reevaluated seismic hazard information stemming from the 50.54(f) letter.
If you have any questions, please contact me at (301) 415-3041 or via e-mail at Stephen.Wyman@nrc.gov.
Docket No.: 50-458 cc: Distribution via Listserv an, Project Manager Hazards nagement Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
ML16259A362 OFFICE NRR/JLD/JHMB/PM NAME SWyman DATE 09/15/2016 Sincerely, IRA/
Stephen Wyman, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation FVega, NRR BTitus, NRR EBowman, NRR MShams, NRR
- via e-mail NRR/JLD/LA NRR/JLD/JHMB/BC(A)
NRR/JLD/JHMB/PM Slent GBowman SWyman 09/23/2016 09/28/2016 09/29/2016