ML15177A274

5/6/2015 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 Nos. MF24

ML15177A274
Person / Time
Site:	South Texas
Issue date:	07/21/2015
From:	Lisa Regner Plant Licensing Branch IV
To:
Regner L
References
TAC MF2400, TAC MF2401, TAC MF2402, TAC MF2403, TAC MF2404, TAC MF2405, TAC MF2406, TAC MF2407, TAC MF2408, TAC MF2409
Download: ML15177A274 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 21, 2015 LICENSEE:

STP Nuclear Operating Company FACILITY:

South Texas Project, Units 1 and 2

SUMMARY

OF MAY 6, 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 May 6, 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. The licensee's handouts from the meeting are available in ADAMS at Accession Nos. ML15119A327 and ML15119A326. 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, March 10, 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 proposed structure of the methodology change submittal which the licensee plans to provide to the staff in June 2015. The June 2015 supplement will provide information on the new Risk over Deterministic methodology, and modify the license amendment requests and exemptions. Another purpose was to provide NRC staff feedback on the request for additional information (RAI) response received from STPNOC by letter dated March 25, 2015.

Meeting Summary The NRC and STPNOC staff continued a discussion from the April 22, 2015, public meeting (meeting summary at ADAMS Accession No. ML15177A104) with the licensee concerning the impacts of requirements in Title 10 of the Code of Federal Regulations (10 CFR), Section 50.67, "Accident source term," and the 10 CFR Part 50, Appendix A, General Design Criterion (GDC) 19, "Control room" on the resolution of GSl-191 for STP. The NRC staff considered the licensee's discussion regarding the criteria it may choose in responding to this RAI.

The NRC staff provided feedback on the draft Section 4.3.2 Sensitivity Study on fiber penetration of the strainer provided by STPNOC (ADAMS Accession No. ML15111A058). The NRC staff noted that the sensitivity results appeared consistent with independent calculations performed by the NRC contractor; however, the staff may have some questions on the filtration modeling and the methodology used to address long-term shedding of fiber from the debris bed.

The NRC staff had no comments on draft Section 5.5 !JLERF [change in Large Early Release Frequency] provided by STPNOC (ADAMS Accession No. ML15111A056).

The NRC staff questioned which computer codes the licensee would use for the mass and energy release, short-and long-term containment response and heat removal analyses in the forthcoming submittal. In the previous submittal, the licensee stated that RELAP and MELCOR codes were used. The current licensing basis information provided in the Updated Final Safety Analysis Report provides the containment response analysis as using CONTEMPT code. The licensee stated that it would answer this question in a future meeting. The NRC staff stated that this information would need to be clarified on the docket, as well.

The need for a technical specification (TS) change was discussed. The licensee stated that operability would be based on deterministic values for containment debris loading and that it does not expect to change TSs to resolve NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors," dated September 13, 2004 (ADAMS Accession No. ML042360586). The NRC staff suggested that further internal discussions would be needed regarding operability.

The NRC staff provided specific items for discussion during the May 11, 2015, audit at the University of New Mexico (the draft audit plan was sent to the licensee by e-mail; it is at ADAMS Accession No. ML 1511 OA463):

Fixed filtration versus time dependent Split fraction based on generic testing The amount of margin to tested debris values LERF and use of Quality Assurance program The NRC staff did not comment on the licensee's handouts and suggested that this would be a topic for a future public meeting.

Action Items Future topics of discussion during biweekly conference calls:

CASA Grande white paper revisions Draft Sections 4.3.2 and 5.5

~LERF Follow-up containment analysis questions Thermal-hydraulics discussion No Public Meeting Feedback Forms or public comments were received for this meeting.

Please direct any inquiries to me at 301-415-1906, orfisa.regner@nrc.gov.

I SincerJ, l Docket Nos. 50-498 and 50-499

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv Li;~-

is M. Regner, Senior Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

LIST OF ATTENDEES MAY 6, 2015, CONFERENCE CALL WITH STP NUCLEAR OPERATING COMPANY REGARDING RISK-INFORMED APPROACH TO RESOLUTION OF GSl-191 NAME Lisa Regner John Stang Victor Cusumano Caroline Tilton Jerry Dozier Ahsan Salman Steve Smith Paul Klein Steve Laur Mike Murray Steve Blossom Drew Richards Ernie Kee Wayne Harrison Wes Schulz Linda Dyer Bruce Letellier Steven M Unikewicz Dave Johnson Don Wakefield Ron Holloway Jeremy Tejada Paul Leonard Seyed Reihani Phillip Grissom SOUTH TEXAS PROJECT, UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499 ORGANIZATION U.S. Nuclear Regulatory Commission (NRC)

NRC NRC NRC NRC NRC NRC NRC NRC STP Nuclear Operating Company (STPNOC)

STPNOC STPNOC STPNOC STPNOC STPNOC STPNOC Alion Science and Technology Alion Science and Technology ABS Consulting ABS Consulting Wolf Creek Nuclear Generating Corporation University of Texas at Austin Enercon University Southern Nuclear Enclosure Follow-up containment analysis questions Thermal-hydraulics discussion No Public Meeting Feedback Forms or public comments were received for this meeting.

Please direct any inquiries to me at 301-415-1906, or lisa.regner@nrc.gov.

Sincerely,

/RAJ 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 DISTRIBUTION:

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NRRIDE/ESGB/BC*

NRR/DSS/STSB/BC*

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