ML15327A168

November 5, 2015, Summary of Meeting with SNC on GSI-191 Program for the Vogtle Electric Generating Plant (CAC Nos. MC4727 and MC4728)

ML15327A168
Person / Time
Site:	Vogtle
Issue date:	11/30/2015
From:	Koenick S S Plant Licensing Branch IV
To:
Koenick S S
References
CAC MC4727, CAC MC4728
Download: ML15327A168 (4)

Text

LICENSEE: Southern Nuclear Operating Company (SNC) FACILITY: Vogtle Electric Generating Plant, Units 1 and 2 (VEGP) SUBJECT: SUMMARY OF NOVEMBER 5, 2015, MEETING WITH SNC ON GSl-191 PROGRAM FOR THE VEGP (CAC NOS. MC4727 AND MC4728) On November 5, 2015, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and SNC representatives at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The licensee's objectives in the meeting were to provide an overview of their risk-informed approach to addressing Generic Safety Issue (GSl)-191, "Assessment of Debris Accumulation on Pressurize-Water Reactor Sump Performance," and receive any comments, concerns or feedback from NRC staff. The meeting notice and agenda, dated October 20, 2015, is available in the Agencywide Documents Access and Management System (ADAMS) Accession No. ML 15308A214. A list of attendees is provided as Enclosure 1. The licensee provided materials to support the meeting and its presentation in advance (ADAMS Accession Nos. ML 15293A180 and ML 15308A031). The licensee revised the slides for the actual meeting (ADAMS Accession No. ML 15320A087). SNC provided a brief description of VEGP, Units 1 and 2, with emphasis on similarities and differences with South Texas pilot. SNC provided a status update to the resolution schedule presented in the VEGP Proposed Path to Closure of GSl-191 dated May 16, 2013 (ADAMS Accession No. ML 13137A130. In that letter, the licensee proposed the use of a risk-informed approach to the resolution of remaining GSl-191 issues. The licensee then provided an overview of their approach followed by more in depth discussions on the various technical aspects of their approach. Discussions included:

• SNC its proposed modifications to the emergency core cooling system (ECCS) strainers and how this will result in increased submergence margins and . submergence of all strainers prior to recirculation in all postulated scenarios. The NRC questioned the adequacy of the current strainer configurations that could result in the strainers not being completely submerged under all conditions. The licensee that in the case of the small-break loss-of-coolant accident, there would not be containment spray, which would greatly reduce the material washed to the strainers and, thus, reduce the debris accumulation. In these scenarios, there would still be adequate net positive suction head (NPSH) for the ECCS pumps.

• SNC described the modeling, quantification and probabilistic distributions of the input variables used to calculate the effects of debris. The licensee discussed modeling of scenarios ranging from fixing variables such at refueling water storage tank heights during suites of scenarios to deterministically reducing the number of scenarios and limiting the usage of input variable distributions. The NRC staff discussion focused on

-2 -the licensee's need to satisfy requirements while presenting an analysis that could facilitate the staff's review.

• SNC and the NRC staff discussed the assumptions concerning chemical precipitate formation. The NRC staff questioned if the licensee had considered evaluating effects on a total amount of precipitate basis instead of separately evaluating calcium phosphate and aluminum hydroxide type precipitates. SNC and the NRC staff also discussed the assumptions made about precipitate timing and whether the proposed method could be simplified to be ,r,nore consistent with approaches that the NRC staff has previously accepted. q

• Throughout the presentation, SNC highlighted differences between their approach and the South Texas pilot.

• No regulatory decisions or commitments were made during the meeting. Members of the public did not participate. Furthermore, no Public Meeting Feedback forms were received. Stephen Koenick, Senior Project Manager Plant Licensing Branch IV-2 and Decommissioning

• Transition Branch

• Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425 Enclosure: List of Attendees cc w/encl: Distribution via Listserv j LIST OF ATTENDEES November 5. 2015 MEETING WITH SNC Licensee Phil Grissom Southern Nuclear Operating Company (SNC) Ryan Joyce SNC Owen Scott SNC Franchelli Febo SNC Tim Littleton SNC Keith Drudy SNC Kip Walker Enercon Services Blake Stair Enercon Services Tim Sande Enercon Services -Haifeng Li* Enercon Services Patrick Romine* Enercon Services Diane Jones Enercon Services Austin Glover I Enercon Services Bob Peterson Sargent & Lundy Helmut Kopke Sargent & Lundy NRC Staff -Stephen Koenick DORL/LPL4-2 Michael Markley DORL/LPL2-1 /BC Jim Trapp DORL/DD Victor Cusumano DSS/SSIB Stephen Smith DSS/SSIB Lindsay Robinson DSS/SSIB John Stang* DSS/SSIB Andrea Russell DSS/SSIB CJ Fong DRA/APLA Steven Laur* DRA/APLA Paul Klein DE/ESGB Matt Yoder* DE/ESGB Marioly Diaz Colon DE/ESGB Bob Martin DORL/LPL2-1 Osvaldo Pensado Southwest Research Institute Other Craig Sellers Calver Cliffs Ron Holloway* Wolf Creek NOC Matthew Thomas* Wolf Creek NOC David Miskiewicz* EPM, Inc. Roger Andreasen* Ameren Missouri Ernie Kee South Texas Project *participation via phone Enclosure

-2 -' '\ the licensee's need to satisfy requirements while presenting an analysis that could facilitate the staff's review.

• SNC and the NRC staff discussed the assumptions concerning chemical precipitate formation. The NRC staff questioned if the licensee had considered evaluating chemical -effects on a total amount of precipitate basis instead of separately evaluating calcium phosphate and aluminum hydroxide type precipitates. SNC and the NRC staff also discussed the assumptions made about precipitate timing and whether the proposed method could be simplified to be more consistent with approaches that. the NRC staff has previously accepted.

• Throughout the presentation, SNC highlighted differences between their approach and the South Texas pilot. No regulatory decisions or commitments were made* during the meeting. Members of the public did not participate. Furthermore, no Public Meeting Feedback forms were received. /RA/ Stephen Koenick, Senior Project Manager Plant Licensing Branch IV-2 and Decommissioning Transition Branch Docket Nos. 50-424 and 50-425 Enclosure: List of Attendees Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation cc w/encl: Distribution via Listserv DISTRIBUTION: RidsACRS_MailCTR Resource RidsNrrDorlLpl2-1 Resource RidsNrrPMVogtle Resource RidsNrrLASFigueroa Resource Resource ADAMS A ccess1on N os.: M eetm! OFFICE DORL/LPLIV-2/PM NAME SKoenick DATE 11/23/15 VCusumano, NRR GKulesa, NRR PKlein, NRR MMarkley, NRR RMartin, NRR JStang, NRR N f ML 14296A292 o ice: DORL/LPLI 1-1 /LA SFigueroa 11/23/15 SSmith, NRR MYoder, NRR TWertz, NRR CJFong, NRR M f S ee mg um mar y: ML 15327A168 DORL/LPLll-1/BC DORL/LPLIV-2/PM MMarkley SKoenick 11/30/15 11/30/15 OFFICIAL RECORD COPY ' 0