ML15177A104

4/22/2015 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 t

ML15177A104
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: ML15177A104 (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 APRIL 22, 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 April 22, 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. ML15111A056 and ML15111A058. An NRC staff handout is available at ADAMS Accession No. ML15112A256. 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 staff noted that an on-site regulatory audit is planned for May 12-14, 2015, so the staff can perform an in-depth review of the analyses performed by the licensee as a resolution to specific portions of GSl-191 employing a risk-informed approach. The risk-informed approach, referred by the licensee as 'RoverD,' and related computations are documented in Attachment 7 in the licensee's letter dated March 25, 2015. The objective of the audit is to evaluate technical approaches implemented in support of the Rovero methodology and to identify related verification and validation activities.

The licensee and NRC staff discussed the licensee's response to question AADB 3 (ADAMS package Accession No. ML14086A383). The staff provided a new question requesting confirmation of the reliability and sufficiency of the containment spray pumps to meet the requirements of Title 10 of the Code of Federal Regulations (10 CFR), Section 50.67, "Accident source term," 10 CFR Part 50, Appendix A General Design Criteria (GDC) 19 "Control room," 10 CFR 20.1201 "Occupational Dose Limits for Adults," and that they will continue to meet the alternate source term criteria in Regulatory Guidance 1.183 (ADAMS Accession No.

ML15112A256).

The NRC staff questioned an assumption in the licensee's large early release frequency (LERF) calculation (i.e., a ratio approach to estimate the LERF attributable to any increase in core damage frequency (CDF) from debris). The NRC staff informed the licensee that it plans to review the LERF calculation during the May audit.

The NRC staff noted reactor compartment coatings concerns regarding the licensee's crud estimates and the use of 5 diameters for unqualified coatings debris size versus the 10 diameters estimates specified in a revision to the NRG-staff approved guidance by letter dated April 6, 201 O (ADAMS Accession No. ML100960495). These will be topics for the next bi-weekly public conference call scheduled for May 6, 2015, at 3:00 p.m. eastern time. Other topics for discussion at the May 5th meeting include the exemption requests, defense-in-depth and safety margin discussion, and debris transport and generation.

No public comments were received and no Public Meeting Feedback Forms were received for this meeting. Please direct any inquiries to me at 301-415-1906, or lisa.regner@nrc.gov.

isa 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 APRIL 22. 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 Lisa Regner U.S. Nuclear Regulatory Commission (NRC)

John Stang NRC Victor Cusumano NRC Caroline Tilton NRC Ashley Guzzetta NRC Steve Smith NRC CJ Fong NRC Jerry Dozier NRC Matt Yoder NRC Paul Klein NRC Osvaldo Pensado Southwest Research Institute (contractor for NRC)

Steve Blossom STP Nuclear Operating Company (STPNOC)

Drew Richards STPNOC Ernie Kee STPNOC Wayne Harrison STPNOC Linda Dyer STPNOC Bruce Letellier Ali on Ron Holloway Wolf Creek Nuclear Generating Corporation Jeremy Tejada University of Texas at Austin Tim Sande Enercon Enclosure

ML15177A104 *by email OFFICE NRR/DORL/LPL4-1 /PM NRR/DORL/LPL4-1 /LA NRR/DSS/STSB/BC* NRR/DSS/SSIB/BC*

NAME LRegner JBurkhardt RElliott VCusumano DATE 6/25/15 6/26/15 7/8/15 7/8/15 OFFICE NRR/DRA/APLA/BC* NRR/DE/ESGB/BC* NRR/DRA/ARCB/BC* NRR/DORL/LPL4-1 /BC NRR/DORL/LPL4-1 /PM NAME SRosenberg GKulesa US hoop MMarkley LRegner DATE 7/8/15 7/10/15 7/15/15 7/21/15 7/21/15