ML15180A273

6/3/2015 Summary of Meeting with STP Nuclear Operating Company to Discuss Revised Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 at South Texas, Units 1 and 2 (TAC MF2400 to

ML15180A273
Person / Time
Site:	South Texas
Issue date:	07/15/2015
From:	Lisa Regner Plant Licensing Branch IV
To:
Watford M
References
TAC MF2400, TAC MF2401, TAC MF2402, TAC MF2403, TAC MF2404, TAC MF2405, TAC MF2406, TAC MF2407, TAC MF2408, TAC MF2409
Download: ML15180A273 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 15, 2015 LICENSEE: STP Nuclear Operating Company FACILITY: South Texas Project, Units 1 and 2

SUMMARY

OF JUNE 3, 2015 PUBLIC MEETING WITH STP NUCLEAR OPERATING COMPANY TO DISCUSS THE LICENSE AMENDMENT AND EXEMPTION REQUESTS TO USE A RISK-INFORMED APPROACH TO THE RESOLUTION OF GENERIC SAFETY ISSUE 191, "ASSESSMENT OF DEBRIS ACCUMULATION ON PWR SUMP PERFORMANCE" (TAC NOS. MF2400, MF2401, MF2402, MF2403, MF2404, MF2405, MF2406, MF2407, MF2408, AND MF2409)

On June 3, 2015, a public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of STP Nuclear Operating Company (STPNOC, the licensee), at NRC Headquarters, Rockville, Maryland. The meeting notice and agenda, dated February 13, 2015, are located in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML15091A578. A list of meeting attendees is provided in the Enclosure to this meeting summary.

By letter dated June 19, 2013 (ADAMS Accession No. ML131750250), as supplemented by letters dated October 3, October 31, November 13, November 21, and December 23, 2013 (two letters); and January 9, February 13, February 27, March 17, March 18, May 15 (two letters),

May 22, June 25, and July 15, 2014; and March 1O and March 25, 2015 (ADAMS Accession Nos. ML13295A222, ML13323A673, ML13323A128, ML13338A165, ML14015A312, ML14015A311, ML14029A533, ML14052A053, ML14072A076, ML14086A383, ML14087A126, ML14149A353, ML14149A354, ML14149A434, ML14178A481, ML14202A045, ML15072A092, and ML15091A440, respectively), STPNOC submitted exemption requests accompanied by a license amendment request (LAR) for a risk-informed approach to resolve Generic Safety Issue (GSl)-191, "Assessment of Debris Accumulation on PWR [Pressurized-Water Reactor] Sump Performance, at South Texas Project, Units 1 and 2 (STP).

The purpose of this public teleconference call was to discuss the licensee's upcoming submittal which the licensee stated it plans to submit in July 2015. The supplement is expected to provide information on the new Risk over Deterministic methodology, and modify the license amendment and exemption requests.

Meeting Summary The NRC staff discussed the need for STPNOC to properly justify the approach used for jet directionality at piping end points, which is used to calculate debris generation in CASA Grande.

The NRC staff stated that the implemented computational approaches should be properly described in the licensee's future submittals, specifically the pipe ends and special jet directionality approaches. The licensee indicated that the NRG-staff-observed random jet

direction on pipe ends during confirmatory calculations was inadvertent, and that this issue was corrected with a change in the computer-assisted design files used as input to CASA Grande.

The licensee stated it would provide an explanation to the adopted approach in the upcoming submittal.

As a follow-up to the jet direction discussion, NRC staff reminded the licensee of the importance of providing accurate information, identifying and disclosing changes in methods of analysis from what was previously provided to the NRC, and the importance of providing a clear, well thought out response to questions.

The NRC staff also discussed the need for STPNOC to address how changes due to debris loading in containment could affect the probabilistic risk analysis (PRA), including changes in risk, defense-in-depth, and safety margins. The NRC staff stated that the licensee needs to either justify that its current long-term monitoring and reporting program is sufficient, or explain its new method and how it will be sufficient in the upcoming submittals.

In its March 25, 2015, response to the NRC staff request for additional information dated March 3, 2015 (ADAMS Accession No. ML14357A171), the licensee indicated that a factor of five times the break diameter (denoted as 5D) to define the zone-of-influence (ZOI) for inorganic zinc coatings was used in the testing, and that this 5D factor will be relied upon for its methodology. The NRC staff pointed out that existing staff guidance, "Revised Guidance Regarding Coatings Zone of Influence for Review of Final Licensee Responses to Generic Letter 2004-02, 'Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors,"' dated April 6, 2010 (ADAMS Accession No. ML100960495), calls for evaluation of inorganic zinc coatings debris generation assuming a 10D ZOI. The NRC staff stated the need for the licensee to address this difference and provide an analysis that accounts for the additional debris generated by the larger ZOI specified in NRC staff approved guidance, in its upcoming submittal. The licensee stated its awareness of the potential inconsistencies, and that it will be addressed in the upcoming submittals.

The NRC staff and the licensee discussed the Updated Final Safety Analysis Report changes, and the licensee stated the changes will be included in the upcoming submittal. The NRC staff informed the licensee that if its current mass and energy release analysis for containment response is based on Westinghouse methodology in WCAP-10325-P-A, ""Westinghouse LOCA Mass and Energy Release Model for Containment Design March 1979 Version," May 1983 (proprietary), the licensee should consider using corrected codes reported in Westinghouse Nuclear Safety Advisory letters.

The NRC staff then asked the licensee about the schedule for the upcoming submittals and if there is a need for another public meeting. The licensee proposed to submit in June of this year. After the public meeting, the NRC staff and the licensee agreed upon a July 2, 2015, public teleconference, which would push back the proposed submittal date to July 2015. The meeting notice for the upcoming July 2 meeting is located in ADAMS at Accession No. ML15173A343.

No Public Meeting Feedback Forms or public comments were received for this meeting.

If you have any questions, please contact me at 301-415-1906 or via e-mail at Lisa. Regner@nrc.gov.

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Lisa M. Regner, Senior Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv

LIST OF ATTENDEES JUNE 3, 2015. CONFERENCE CALL WITH STP NUCLEAR OPERATING COMPANY REGARDING RISK-INFORMED APPROACH TO RESOLUTION OF GSl-191 SOUTH TEXAS PROJECT. UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499 NAME ORGANIZATION Margaret Watford U.S. Nuclear Regulatory Commission (NRC)

John Stang NRC Victor Cusumano NRC Matt Yoder NRC Paul Klein NRC Jerry Dozier NRC CJ Fong NRC Ahsan Sallman NRC Steve Smith NRC Balwant Singal NRC Marioly Diaz Colon NRC Steve Laur NRC Lindsay Robinson NRC Caroline Tilton NRC Osvaldo Pensado Southwest Research Institute (contractor for NRC)

Mike Murray STP Nuclear Operating Company (STPNOC)

Steve Blossom STPNOC Rob Engen STPNOC Ernie Kee STPNOC Wayne Harrison STPNOC Linda Dyer STPNOC Bruce Letellier Ali on Tim Sande Enercon Enclosure

ML15180A273 *per email OFFICE NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1/LA NRR/DSS/SSIB/BC NRR/DSS/STSB/BC NAME LRegner (MWatford for) JBurkhardt VCusumano RElliott DATE 7/1 /15 6/30/15 7/8/15 7/8/15 OFFICE NRR/DRA/APLA/BC NRR/DE/ESGB/BC NRR/DORL/LPL4-1 /BC NRR/DORL/LPL4-1 /PM NAME SRosenberg GKulesa MMarkley (Flyon for) LRegner DATE 7/8/15 7/10/15 7/15/15 7/15/15