ML112130165

7/26/11 - Summary of Conference Call with STP Nuclear Operating Company to Discuss Risk-Informed GSI-191, Assessment of Debris Accumulation on Pressurized-Water Reactor (PWR) Sump Performance, Resolution Approach for South Texas, Units 1 an

ML112130165
Person / Time
Site:	South Texas
Issue date:	08/19/2011
From:	Balwant Singal Plant Licensing Branch IV
To:	Office of Nuclear Reactor Regulation
Singal, Balwant, 415-3016, NRR/DORL/LPL4
References
TAC ME5358, TAC ME5359, GSI-191
Download: ML112130165 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 19, 2011 LICENSEE: STP Nuclear Operating Company FACILITY: South Texas Project, Units 1 and 2

SUMMARY

OF JULY 26, 2011, PRE-LICENSING PUBLIC MEETING VIA CONFERENCE CALL WITH STP NUCLEAR OPERATING COMPANY TO DISCUSS THE PROPOSED RISK-INFORMED APPROACH TO THE RESOLUTION OF GSI-191, "ASSESSMENT OF DEBRIS ACCUMULATION ON PWR SUMP PERFORMANCE" (TAC NOS. ME5358 AND ME5359)

On July 26, 2011, a public meeting via 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, MD. The meeting notice and agenda, dated July 12, 2011, is located at Agencywide Documents Access and Management System (ADAMS) Accession No. ML111861529. The purpose of the meeting was to discuss the proposed risk-informed approach to the resolution of GSI-191, "Assessment of Debris Accumulation on PWR [pressurized-water reactor] Sump Performance." South Texas Project (STP) is the lead plant and STPNOC plans to submit a License Amendment Request (LAR) in mid-2012. The licensee previously provided an overall view of the proposed approach to the NRC staff during the public meetings held on June 2 and July 6, 2011. The purpose of this conference call was to provide an overview of the Containment Accident Sequence Stochastic Analysis (CASA) Grande method for calculating the effects of debris generated from a spectrum of postulated accidents on emergency core cooling system pump performance. The licensee also discussed the topic of Computational Fluid Dynamics (CFD) verification plans during this conference call.

The licensee's presentation slides and additional materials provided for the meeting are located at ADAMS Accession No. ML112070702. A list of meeting attendees is provided in the Enclosure to this meeting summary.

Meeting Summary The licensee provided a copies of the following presentations prior to the meeting:

1. Models and Methods Used for CASA Grande

a. Role of CASA Grande in Risk-Informed Resolution of GSI-191

b. Complexities of Debris Generation, Transport, and Sump Blockage (DGTSB) - Reactor Accident Phenomena

c. Strategies for Stochastic Modeling of DGTSB in CASA

d. Required Inputs to CASA Grande

-2

e. Topical Approach and Implementation Plan for Debris Generation, Debris Transport, Head Loss, Air Intrusion, and Debris Bypass

f. Interface to PRA

2. CFD Validation Plan Due to lack of time, however, the discussion on subtopics 1.d, 1.e, and 1.f could not be completed and it was decided to complete the discussions of the rest of the sub-topics during the meeting proposed for August 22, 2011 (meeting notice and agenda dated August 2, 2011, which is available at ADAMS Accession No. ML112130182).

The licensee presented an overview of the models and methods used for CASA Grande for subtopics 1.a, 1.b, and 1.c. The presentation covered the following in more detail:

Role of CASA Grande in Risk-Informed Resolution of GSI-191

• Deterministic Resolution Path

• Risk-Informed Resolution Path

• Purpose, Role, and Functionality of CASA Grande Complexities of DGTSB - Reactor Accident Phenomena

• Accident Progression Overview

• Complex Phenomenology and Phenomena Strategies for Stochastic Modeling of DGTSB in CASA

• South Texas Project Key Attributes

• Time Dependent Performance Metrics

• Time Dependent Containment Programs (Cold-Leg DEGB [Double-Ended Guillotine Break] in Large Dry Containment)

• Basic Probability Descriptions

• Time Dependent Failure Probability and Tracking time Dependence

• Propagation of Variability

• CASA Grande Random Factors

• Performance metrics The NRC staff had only some clarification questions during the presentation. The NRC staff suggested that for future conference call public meetings, the scope of the presentations should be kept at a higher over-view level and the details should be discussed during the face-to-face meetings.

- 3 Action Items There were no action items as a result of this meeting. It was agreed to arrange the next face to-face public meeting at NRC headquarters on August 22,2011.

No Public Meeting Feedback Forms were received for this meeting.

Please direct any inquiries to me at (301) 415-3016, or Balwant.Singal@nrc.gov.

Sincerely,

~~. \ w ~.~ ~Qb ,w~

Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV 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 JULY 26. 2011. PRE-LICENSING MEETING RISK-INFORMED APPROACH TO RESOLUTION OF GSI-191 ISSUE STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PROJECT. UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499 NAME TITLE ORGANIZATION Balwant K. Singal Senior Project Manager NRC/NRR/DORL Donnie Harrison Branch Chief NRC/NRR/DRAIAPLA Stephen Dinsmore Senior Reliability Risk Analyst NRC/NRR/DRAIAPLA Steven Laur Senior Reliability Risk Analyst NRC/NRR/DRAIAPLA John Lehning Reactor System Engineer NRC/NRR/DSS/SNPB Steve Smith Reactor System Engineer NRC/NRR/DSS/SSIB Ralph Architzel Senior Reactor Engineer t\lRC/t\lRR/DSS/SSIB Stewart Bailey Branch Chief NRC/NRR/DSS/SSIB Ervin Geiger Reactor System Engineer NRC/NRR/DSS/SSIB Wes Schultz - STPNOC Sarah Wright Administrative Assistant STPNOC Steve Blossom Project Manager, Special Projects STPNOC Jamie Paul Licensing STPNOC Ernie Kee Risk Management STPNOC Rick Grantom Manager Risk Project STPNOC Tim Sande* Principal Mechanical Engineer Alion Science and Technology Matthew Brandes** -- Ameren John Swailes** -- Calvert Cliffs Bruce Lettellier* - Los Alamos National Laboratory Jana Bergman** -- Scientech Rodolfo Vaghetto* PhD Student Texas A&M University Yassin Hassan* Professor Texas A&M University Elmira Popova* - University of Texas at Austin

• Represented STPNOC

• • Public Abbreviations:

NRC - U.S. Nuclear Regulatory Commission NRR - Office of Nuclear Reactor Regulation DORL - Division of Operating Reactor Licensing STPNOC - STP Nuclear Operating Company ORA - Division of Risk Assessment DSS - Division of Safety Systems SSIB - Safety Issues Resolution Branch SNPB - Nuclear Performance and Code Review Branch APLA - PRA Licensing Branch Enclosure

- 3 Action Items There were no action items as a result of this meeting. It was agreed to arrange the next face to-face public meeting at NRC headquarters on August 22, 2011.

No Public Meeting Feedback Forms were received for this meeting.

Please direct any inquiries to me at (301) 415-3016, or Balwant.Singal@nrc.gov.

Sincerely, Ira!

Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV 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:

PUBLIC CSteger, NRR LPLIV r/f SBush-Goddard, EDO RIV RidsAcrsAcnw_MailCTR Resource SDinsmore, NRRlDRAlAPLA RidsNrrDssSsib Resource SPumell, NRR/DPRlPGCS RidsNrrDraApla Resource DHarrison, NRRlDRAlAPLA RidsNrrDssSnpb Resource SSmith, NRR/DSS/SSIB RidsNrrDorlLpl4 Resource EGeiger, NRRlDSS/SSIB RidsNrrPMSouthTexas Resource SBailey, NRR/DSS/SSIB RidsNrrLAJBurkhardt Resource SLaur, NRR/DRAIAPLA RidsOgcRp Resource RArchitzel, NRR/DSS/SSIB RidsRgn4MailCenter Resource JLehning, NRRlDSS/SNPB ADAMS Accession No. ML112130165

,~~

OFFICE NRRlLPL4'~'" NRRlDSS/SSIBIBC NRRlDRAlAPLNBC NRRlLPL4IBC NRRlLP NAME BSingal IJBurkhardt SBailey (SSmith for) DHarrison MMarkley (RHall for) BSingal II DATE 812111 812111 813/11 8/4/11 8/19f11 8/19/11 II OFFICIAL RECORD COpy