ML19207A017

Summary of Meeting with Duke Energy Carolinas, LLC to Discuss Proposed License Amendment Request for Oconee Nuclear Station, Units 1, 2, and 3 Regarding High Energy Line Break Licensing Basis

ML19207A017
Person / Time
Site:	Oconee
Issue date:	07/30/2019
From:	Audrey Klett Plant Licensing Branch II
To:
Klett A, 415-0489
References
EPID L-2019-LRM-0042
Download: ML19207A017 (28)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 30, 2019 LICENSEE: Duke Energy Carolinas, LLC FACILITY: Oconee Nuclear Station, Units 1, 2, and 3

SUMMARY

OF JUNE 26, 2019, MEETING WITH DUKE ENERGY CAROLINAS, LLC TO DISCUSS PLANNED LICENSE AMENDMENT REQUEST FOR OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 REGARDING HIGH ENERGY LINE BREAK LICENSING BASIS (EPID L-2019-LRM-0042)

On June 26, 2019, the U.S. Nuclear Regulatory Commission (NRC) staff held a Category 1 public meeting with representatives from Duke Energy Carolinas, LLC (the licensee) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss a planned license amendment request (LAR) to clarify and change the high energy line break (HELB) licensing basis for the Oconee Nuclear Station, Units 1, 2, and 3 (Oconee). The meeting notice and agenda, dated June 12, 2019, are available in NRC's Agencywide Documents Access and Management System (ADAMS) under Accession No. ML19163A068. A list of attendees and the meeting presentation material are enclosed.

The licensee presented background material for its planned LAR to modify the Oconee Updated Final Safety Analysis Report (UFSAR) related to mitigation of HELBs. Enclosure 2 of this meeting summary contains the presentation slides that the licensee provided to the NRC staff.

The licensee plans to submit the LAR in summer 2019. The licensee stated that it intends the planned LAR to supersede its previously submitted LAR on this subject, as supplemented, for which the NRC suspended its review.

The licensee gave the staff a presentation of the purpose of the planned submittal and described its assumptions used in analyses and the plant's design features for mitigating a HELB. The licensee stated that it completed a comprehensive review of its HELB licensing basis. The licensee plans to propose various mitigation strategies depending on which systems are assumed lost after a HELB. The licensee states that it plans to propose modifying the break selection criteria allowed in NRC guidance, using NUREG/CR-2913, "Two-Phase Jet Loads" (ADAMS Accession No. ML073510076}, for determining the effective length of jets from a HELB or critical crack, using a repair strategy for establishing cold shutdown for breaks postulated to occur in the turbine building, and maintaining HELB as a separate and distinct requirement versus the pipe ruptures considered as desigl] basis events (e.g., main steam line breaks). The licensee discussed the elements of the planned proposal, including a rewrite of Chapter 3.6 of the Updated Final Safety Analysis Report (UFSAR), no Technical Specifications changes, regulatory commitments, and thermal hydraulic models.

The NRC staff asked questions about the licensee's intended use of its regulatory commitments and which ones were completed, how the protected service water and standby shutdown facility would work together to mitigate HELBs, whether this submittal would have any reliance on another submittal currently under review, whether the new submittal would revise the GOTHIC auxiliary building heat-up analysis (the licensee indicated that it would), and whether this would

impact the environmental qualification evaluation of electrical equipment, what information could be made available during a potential audit, which thermal-hydraulic codes would be used, mapping information from the previous HELB submittals to the new submittal (if applicable), how any damage from flooding to the low pressure systems in the turbine building would be addressed, any new or changed time-critical manual operator actions associated with the planned changes, bounding dose analyses, and whether the dose analyses would be captured in Chapter 15 of the UFSAR. The licensee indicated that the HELB analysis was performed using the RELAP code.

The staff did not make any regulatory decisions or commitments at the meeting. No members of the public attended the meeting nor were announced over the telephone.

Any inquiries can be directed to me at 301-415-0489 or via e-mail at Audrey.Klett@nrc.gov.

Audrey L. Klett, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287

Enclosures:

1. List of Attendees

2. Meeting Presentation Material cc: Listserv

Enclosure 1 List of Attendees

LIST OF ATTENDEES JUNE 26, 2019, MEETING WITH DUKE ENERGY CAROLINAS, LLC OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 PLANNED LICENSE AMENDMENT REQUEST REGARDING HIGH ENERGY LINE BREAK LICENSING BASIS U.S. Nuclear Regulatory Commission Stewart Bailey Josh Borromeo*

Jorge Cintron-Rivera*

Gordon Curran Matt Hamm Bruce Heida Victoria Huckabay Steve Jones Audrey Klett Mike Markley John Parillo Shie-Jeng Peng Robert Pettis Ahsan Sallman Duke Energy Carolinas, LLC Art Zaremba Dean Hubbard Timothy Brown Jason Patterson Chris King Eric Henshaw Lee Kanipe*

Greg Byers*

Charles Stroupe*

• Participated by phone

Enclosure 2 Meeting Presentation Material

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High Energy Line Break License Amendment Request Pre-Application Meeting

(-,DUKE One White Flint, Rockville, MD June 26, 2019

~ ENERGY

Duke Attendees:

• Dean M. Hubbard (Dean) Oconee Regulatory Projects

• Timothy D Brown (Tim) Oconee Regulatory Projects

• Christopher P King (Chris) Oconee Regulatory Projects

• Jason A Patterson (Jason) Oconee Regulatory Projects

• Michael E Henshaw (Eric) Fleet Safety Analysis

• Arthur Zaremba (Art) Nuclear Fleet Licensing

• Opening Remarks

• Oconee High Energy Line Break (HELB) Current Licensing Basis (CLB)

• HELB Licensing Timeline

• HELB Commitments

• New HELB Licensing Basis (LB)

• New HELB Licensing Documentation

• Discussion of HELB LAR

• New HELB Commitments

• Closing Remarks

High Energy Line Break License Amendment Request

• Oconee Nuclear Station is preparing to submit a license amendment to clarify and update the High Energy Line Break (HELB) licensing basis.

• The submittal will supersede the original 1973 HELB current licensing basis and the 2011 LAR submittal.

• This is the culmination of many hours of analysis, plant surveys, and meetings with the NRC technical staff.

• The revised LAR is based on over 3600 breaks/cracks postulated per unit and over sixty new calculations that were created in the reconstitution project.

• The remaining 2017 re-baselined HELB commitments are to be completed. New commitments are provided in this LAR.

• HELB was originally licensed during the 1973 timeframe to the Giambusso/Schwencer requirements.

• Safe shutdown capability maintained following HELB.

• No structural damage preventing ability to reach cold shutdown.

• Single active failure required.

• Environmental conditions shall not impact mitigating electrical equipment.

• Oconee responded to the Giambusso/Schwencer letters through design report MOS OS-73.2, "Analysis of Effects Resulting from Postulated Piping Breaks Outside Containment for Oconee Nuclear Station, Units 1, 2, & 3."

• High Energy (HE) Systems are defined as systems whose normal service (100°/o power) operating temperature is greater than 200 degrees F or normal service operating pressure greater than 275 psig.

• Approximately 40 break locations are postulated and descriptions of the safe shutdown strategies for those breaks that affect the response of the core and Reactor Coolant System (e.g. Postulated ruptures in the Main Steam and Main Feedwater systems).

• HELB was not defined as a design basis event in the Oconee CLB.

• The Atomic Energy Commission approved the design report as part of the initial Units 2 & 3 SER (7/6/1973).

• 1998 NRC Inspection Report violations - Oconee committed to reconstitute the H ELB licensing basis.

• 2001-2005 Oconee worked with the NRC to gain agreement on criteria for identifying high energy systems, postulated break and crack locations, modes of plant operations applicable to postulated breaks, and postulation of single failures.

• 2007 NRC letter provided general agreement with the criteria to be used in the HELB analyses ("McGinty Letter").

• 2008-2009 Oconee submitted unit specific LARs.

• 2011 The Unit specific LARs were consolidated into one LAR and resubmitted.

• 2012 The NRC suspended review of the HELB LAR to concentrate on licensing PSW.

• PSW SER Received - August 13, 2014.

• PSW Installation Complete - December 22, 2015.

HELB Commitments from 2017 Re-baseline

• 45 Original Commitments.

• 11 Remain to be completed.

Notable HELB Commitments Completed

• Flood outlet devices, flood impoundment, and exterior door improvements for the Units 1, 2, & 3 East Penetration Room (EPR) and Auxiliary Building.

Notable HELB Commitments Completed/ continued

• Remote operators for Unit 1 and 3 valves HP-103 & HP-107 on the individual suction-lines to the 'A' & 'B' High Pressure Injection (HPI) pumps.

• Operator change out of Unit 2 and 3 normal letdown valves HP-1 & HP-2.

• Protected Service Water. (move to previous page)

Remaining HELB Commitments

• Structural modifications to selected columns in the Turbine Building.

• Control Complex HVAC modifications.

• Remote operators for Unit 2 valves HP-103 & HP-107 on the individual suction-lines to the 'A' & 'B' High Pressure Injection (HPI) pumps.

• Operator change out of Unit 1 normal letdown valves HP-1 & HP-2.

• Proposes the PSW system or SSF for HELB mitigation when a HELB results in the loss of plant systems needed for safe shutdown (SSD) inside the turbine building (TB).

• Proposes normal plant systems (i.e., high pressure injection (HPI),

emergency feedwater (EFW)) or the SSF for HELB mitigation when a HELB results in the loss of plant systems needed for SSD inside the auxiliary building (AB).

• Proposes normal plant systems for HELB mitigation when a HELB occurs outside of the TB or AB.

• Excludes systems and subsystems from HELB consideration due to the short time these systems operate at HE conditions.

• Modifies break selection criteria as allowed by Generic Letter (GL) 87-11 and portions of the Standard Review Plan (SRP) Branch Technical Position (BTP) Mechanical Engineering Branch (MEB) 3-1.

• Proposes the use of NUREG/CR-2913 for the determination of effective length of jets from a H ELB or critical crack.

• Proposes the use of a repair strategy for establishment of cold shutdown (CSD) for breaks postulated to occur in the TB.

• Maintains HELB as a separate and distinct requirement versus the pipe ruptures considered as design basis events (e.g. Main Steam Line Breaks).

• Licensing Document Changes

• Supersedes original 1973 CLB responses to the Giambusso/Schwencer letters.

• Supersedes the 2011 LAR submittal.

• Significant rewrite of UFSAR Chapter 3.6, including:

• Methodology for the identification of HE systems.

• Methodology for the identification of break/crack locations.

• Methodology for the determination of break types.

• Shutdown Sequence Evaluation Criteria.

• Interaction Evaluation Criteria.

• Overall HELB Mitigation Strategy (including Safe Shutdown objectives and functions to meet those objectives).

• No changes to Technical Specifications.

• LAR Composition (NEI 06-02 guidelines)

• Cover Letter

• Enclosure

• 1.0 Summary Description.

• 2.0 Detailed Description.

• System Design and Operation.

• Current Technical Specifications Requirements.

• Reason for the Proposed Change.

• Description of the Proposed Change.

• UFSAR Changes.

• LAR Composition / continued

• Enclosure / continued

• 3.0 Technical Evaluation.

• Purpose and Methodology.

• HELB Strategy.

• Regulatory Requirements.

• Arbitrary Intermediate HELBs and Critical Cracks.

• Excluded Systems.

• Operations Response, Training and Procedures.

• Thermal Hydraulic Analyses.

• LAR Composition / continued

• Enclosure / continued

• 4.0 Regulatory Evaluation.

• Applicable UFSAR.

• Precedents.

• Significant Hazards Consideration.

• 5.0 Environmental Consideration.

• 6.0 References.

• 7 .0 Acronyms.

• LAR Composition / continued

• Attachments

• Attachment 1 Regulatory Commitments.

• Attachment 2 UFSAR Markups.

• Attachment 3 UFSAR Retypes.

• Attachment 4 Thermal Hydraulic Models for High Energy Line Break Transient Analysis (Proprietary).

• Attachment 5 Thermal Hydraulic Models for High Energy Line Break Transient Analysis (Non-Proprietary).

• Attachment 6 Thermal Hydraulic Transient Analysis for Evaluation of High Energy Line Breaks.

• LAR Composition / continued

• Attachments I continued

• Attachment 7 Duke Proprietary Affidavit.

• Attachment 8 Framatome Proprietary Affidavit.

• Attachment 9 Regulatory Requirements.

• Attachment 10 Definitions.

• Attachment 11 Time Critical Operator Actions.

• Attachment 12 Letdown Line Break (Dose Analysis).

New HELB Commitments

• QA-1 SSF CR Instrumentation for Steam Generator pressure, nuclear instrumentation, core exit thermocouples, pressurizer temperature, and temperature compensated pressurizer level.

• Elimination of cross connect Control Rod Drive power between units.

• Upgraded SSF Letdown line.

• Modification to isolate Low Pressure Service Water valves 1,2,3LPSW-1119 and 1120.

• Oconee Nuclear Station license amendment on High Energy Line Break will clarify and update the sites license basis for HELB.

• Substantial resources and time have been invested to address regulatory questions and to assure that the site is prepared to respond to an unlikely HELB event.

• A majority of the prior HELB commitments have been met including significant plant modifications that have already been completed.

• Additional modifications to support an updated HELB response are planned and budgeted to complete the site's HELB response.

• The site looks forward to working with the NRC to complete the HELB LAR review.

SUMMARY

OF JUNE 26, 2019, MEETING WITH DUKE ENERGY CAROLINAS, LLC TO DISCUSS PLANNED LICENSE AMENDMENT REQUEST FOR OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 REGARDING HIGH ENERGY LINE BREAK LICENSING BASIS (EPID L-2019-LRM-0042) DATED JULY 30, 2019 DISTRIBUTION:

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DATE 7/30/19 07/30/19 7/30/19 OFFICE NRR/DORL/LPL2-1 /PM NAME AKlett DATE 7/30/19 OFFICIAL RECORD COPY