ML16302A120
| ML16302A120 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/01/2016 |
| From: | Frankie Vega Japan Lessons-Learned Division |
| To: | Gerry Powell South Texas |
| Vega F, NRR/JLD, 415-1617 | |
| References | |
| CAC MF7878, CAC MF7879 | |
| Download: ML16302A120 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. G. T. Powell Executive Vice President and CNO STP Nuclear Operating Company South Texas Project P.O. Box 289 VVadsworth, TX 77483 November 1, 2016
SUBJECT:
SOUTH TEXAS PROJECT, UNITS 1 AND 2 - STAFF REVIEVV 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 (CAC NOS. MF7878 AND MF7879)
Dear Mr. Powell:
The purpose of this letter is to provide the U.S. Nuclear Regulatory Commission's (NRC's) assessment of the seismic hazard mitigation strategies assessment (MSA), as described in an September 29, 2016, letter (Agencywide Documents Access and Management System (ADAMS) Accession No. ML16300A267), submitted by STP Nuclear Operating Company (the licensee) for South Texas Project, Units 1 and 2 (STP). The MSA confirms that the licensee has adequately addressed the reevaluated seismic hazard within its mitigating strategies for beyond-design-basis external events.
BACKGROUND By letter dated March 12, 2012 (ADAMS Accession No. ML12053A340), the NRC 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 NRC 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 10 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 31, 2014 (ADAMS Accession No. ML14099A235), the licensee provided its reevaluated seismic hazard for STP 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 NRG 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 letters dated October 26, 2015, and November 19, 2015 (ADAMS Accession Nos.
ML15287A077 and ML15313A304, respectively), the NRG staff documented its review of the licensee's reevaluated seismic hazard, also referred to as the mitigating strategies seismic hazard information. The staff confirmed the licensee's conclusion that its reevaluated seismic hazard is bounded by the current design basis at all frequencies above 1 Hertz. In addition, the staff concluded that the ground motion response spectrum determined by the licensee adequately characterizes the reevaluated seismic hazard for the STP site.
Appendix H of NEI 12-06, Revision 2, describes acceptable methods for demonstrating that the reevaluated seismic hazard is addressed within the STP mitigating strategies for beyond-design-basis external events. The licensee stated that the STP MSA was performed consistent with NEI 12-06, Revision 2. The NRG staff confirmed that the licensee's seismic hazard MSA is consistent with the guidance in Appendix H.4.1 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 NRG staff has reviewed the seismic hazard MSA for STP. The NRG 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) 415-1617 or via e-mail at Frankie. Vega@nrc.gov.
Docket Nos. 50-498 and 50-499 cc : Distribution via Listserv Sincerely, Fran ie V2:anager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation
ML16302A120 OFFICE NRR/JLD/JHMB/PM NAME FVega DATE 11/01/2016 Sincerely, IRA/
Frankie Vega, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation FVega, NRR BTitus, NRR EBowman, NRR GBowman, NRR NRR/JLD/LA Slent 10/31/2016