ML16279A331

Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409)

ML16279A331
Person / Time
Site:	South Texas
Issue date:	10/27/2016
From:	Lisa Regner Plant Licensing Branch IV
To:	Gerry Powell South Texas
Regner L
References
CAC MF2400, CAC MF2401, CAC MF2402, CAC MF2403, CAC MF2404, CAC MF2405, CAC MF2406, CAC MF2407, CAC MF2408, CAC MF2409
Download: ML16279A331 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 27, 2016 LICENSEE:

STP Nuclear Operating Company FACILITY:

South Texas Project, Units 1 and 2

SUMMARY

OF SEPTEMBER 14, 2016, PUBLIC CONFERENCE CALL 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" (CAC NOS. MF2400, MF2401, MF2402, MF2403, MF2404, MF2405, MF2406, MF2407, MF2408, AND MF2409)

On September 14, 2016, a Category 1 public conference call 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 September 1, 2016, are located in the Agencywide Documents Access and Management System (ADAMS) at Accession No. ML16258A451. A list of meeting attendees is provided in the Enclosure to this meeting summary.

By letter dated June 19, 2013 (ADAMS Package Accession No. ML131750250), as supplemented by letters dated October 3, October 31, November 13, November 21 and December 23, 2013 (two letters); January 9, February 13, February 27, March 17, March 18, May 15 (two letters), May 22, June 25, and July 15, 2014; March 10, March 25, and August 20, 2015; and April 13, May 11, June 9, June 16, July, 18, July 21 (two letters), July 28, 2016 (ADAMS Accession Nos. ML13295A222, ML13323A673, ML13323A128, ML13338A165, ML14015A312, ML14015A311, ML14029A533, ML14052A110, ML14072A075, ML14086A383, ML14087A126, ML14149A353, ML14149A354, ML14149A439, ML14178A467, ML14202A045, ML15072A092, ML15091A440, ML15246A125, ML16111B204, ML16154A117, ML16176A148, ML16196A241, ML16209A226, ML16229A189, ML16230A232, and ML16221A393, respectively), STPNOC submitted exemption requests accompanied by a license amendment request 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 meeting was to discuss the NRC staff's remaining unresolved concerns associated with the licensee's August 20, 2015, document, which provided information on STPNOC's revised methodology to resolve GSl-191 using a risk methodology combined with a deterministic methodology - 'Risk over Deterministic' or 'RoverD.' The meeting focused on the NRC staff's questions following the request for additional information (RAI) responses provided in the May 11, June 16, July 18, July 21 (two letters), and July 28, 2016, letters.

The STPNOC staff provided draft documents for the thermal-hydraulic and debris generation and transport analysis in response to questions from the NRC staff:

Question Original Response Draft Response Accession No. and Date Accession No. and Date Follow-up RAl-33 ML16209A226 7/18/2016 ML16258A098 9/13/2016 Follow-up RAl-34 ML16209A226 7/18/2016 ML16258A208 9/14/2016 Follow-up RAl-37 ML16196A241 6/16/2016 ML16258A207 9/14/2016 SSIB-3-4 (SSIB)

ML16209A226 7/18/2016 ML16258A096 9/13/2016 SNPB-3-2 (SNPB)

ML16258A100 09/12/2016 ML16154A127 5/11/2016 SNPB-3-2 Bullet 4 ML16258A367 9/06/2016 SNPB-3-13 (SNPB)

ML16154A127 5/11/2016 ML16258A104 9/12/2016 All questions are from NRC RAI Round 3 dated 4/11/2016 at Accession No. ML16082A507.

For questions SSIB-3-4 and follow-up RAI 37, the NRC staff determined that the draft response that STPNOC sent in for the call was a good clarification, but was not required to be put on the docket since the NRC had enough information from the most recent RAI responses to consider the issues resolved.

For follow-up questions RAls 33 and 34, the NRC staff discussed that it could neither determine the amount of margin between the containment pressure credited to prevent flashing and to suppress deaeration, nor the amount of containment pressure that might be available under less favorable conditions. The NRC staff and licensee discussed several ways to prove that this margin exists to be able to satisfy the NRC staff's criteria. For follow-up question RAI 34, the NRC staff noted that the information provided was beneficial for the staff to understand the plant conditions that could occur.

The NRC staff and licensee discussed the answers to SNPB-3-2 and SNPB-3-13. The NRC staff stated that the answers to SNPB-3-2 concerning the 16-inch bounding break appear to address the staff's concerns. For SNPB-3-13 concerning the counter-current flow limitation, the NRC staff noted that Figure 2 and Figure 3 are the same chart. The corrected charts need to be included in the final STPNOC submittal (planned for mid-October). Also, the NRC staff discussed that the information on counter-current flow in the draft response appears complete, but that there were still aspects of the question that were not discussed fully including model validation. Finally, the NRC staff requested information on the STP core bypass flow testing previously completed that shows that debris will not significantly impact this flow.

The NRC staff reminded STPNOC that a final determination of acceptability cannot be made until a formal submittal is provided.

The probabilistic risk analysis model core damage frequency and large early release frequency values were submitted formally by STPNOC staff by letter dated September 12, 2016 (ADAMS Accession No. ML16272A162).

There were no public comments or questions and no meeting feedback received.

If you have any questions, please contact me at 301-47 906 or via e-mail at Lisa.Regner@nrc.gov.

SincerelY, Docket Nos. 50-498 and 50-499

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv

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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

LIST OF ATTENDEES SEPTEMBER 14. 2016. PUBLIC MEETING WITH STP NUCLEAR OPERATING COMPANY REGARDING RISK-INFORMED APPROACH TO RESOLUTION OF GSl-191 NAME Lisa Regner Vic Cusumano Josh Kaizer Reed Anzalone CJ Fong Steven Laur Mike Murray Rob Engen Ernie Kee Wayne Harrison Steve Blossom Wes Schulz Drew Richards Rodolfo Vaghetto Dominic Munoz Craig Sellers Tim Sande Ron Holloway Eric Fulhage 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 STP Nuclear Operating Company (STPNOC)

STPNOC STPNOC STPNOC STPNOC STPNOC STPNOC Texas A&M University Alien Science and Technology Calvert Cliffs Nuclear Power Plan Enercon Wolf Creek Nuclear Generating Corp.

Engineering, Planning & Management, Inc.

Enclosure

ML16279A331

• per email OFFICE NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1 /LA NRR/DSS/SSIB/BC*

NRR/DSS/SNPB/BC*

NAME LRegner JBurkhardt VCusumano Rlukes DATE 10/04/16 10/18/16 10/26/16 10/05/16 OFFICE NRR/DRA/APLAITL

• NRR/DORL/LPL4-1 /BC NRR/DORL/LPL4-1 /PM NAME CJ Fong RPascarelli LRegner DATE 10/20/16 10/27/16 10/27/16