ML19338C151

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Regulatory Audit Report (LAR-19-014)
ML19338C151
Person / Time
Site: Vogtle  Southern Nuclear icon.png
Issue date: 12/18/2019
From: Bill Gleaves
NRC/NRR/VPOB
To: Victor Hall
NRC/NRR/VPOB
GLEAVES B/415-5848
References
LAR-19-014
Download: ML19338C151 (11)
v • d • e


Text

December 18, 2019 MEMORANDUM TO: Victor E. Hall, Chief Vogtle Project Office Office of Nuclear Reactor Regulation FROM: William (Billy) Gleaves, Senior Project Manager /RA/

Vogtle Project Office Office of Nuclear Reactor Regulation

SUBJECT:

AUDIT REPORT RELATED TO LICENSE AMENDMENT REQUEST (LAR)19-014 - TORNADO MISSILE PROTECTION FOR MAIN STEAM VENT STACKS AND WALL 11 The U.S. Nuclear Regulatory Commission staff conducted an audit of documents related to the Vogtle Electric Generating Plant Units 3 and 4 proposed license amendment request (LAR)19-014, Tornado Missile Protection for Main Steam Vent Stacks and Wall 11. The audit was conducted at various dates and times, as planned, between October 15, 2019, and December 5, 2019, at the virtual Southern Nuclear Operating Company/Westinghouse Electric Companys electronic reading room. A summary report of the audit is enclosed.

CONTACT: Billy Gleaves, NRR/VPO 301-415-5848

ML19338C151 *via email NRO-008 OFFICE NRR/VPO:PM NRR/VPO:LA NRR/ESEA:BC NRR/SBPB:BC NRR/EMIB:BC NRR/VPO/BC NAME WGleaves RButler DWilliams* BWittick* KHsu* for SBailey VHall DATE 12/18/19 12/5/19 12/9/19 12/09/19 12/06/19 12/16/19 Vogtle Mailing List (Revised 11/12/2019) cc:

Resident Manager Resident Inspector Oglethorpe Power Corporation Vogtle Plant Units 3 & 4 Alvin W. Vogtle Nuclear Plant 8805 River Road 7821 River Road Waynesboro, GA 30830 Waynesboro, GA 30830 Mr. Barty Simonton Office of the Attorney General Team Leader 40 Capitol Square, SW Environmental Radiation Program Atlanta, GA 30334 Air Protection Branch Environmental Protection Division Southern Nuclear Operating Company 4244 International Parkway, Suite 120 Document Control Coordinator Atlanta, GA 30354-3906 3535 Colonnade Parkway Birmingham, AL 35243 Brian H. Whitley Regulatory Affairs Director Anne F. Appleby Southern Nuclear Operating Company Olgethorpe Power Corporation 3535 Colonnade Parkway, BIN N-226-EC 2100 East Exchange Place Birmingham, AL 35243 Tucker, GA 30084 Mr. Michael Yox County Commissioner Site Regulatory Affairs Director Office of the County Commissioner Vogtle Units 3 & 4 Burke County Commission 7825 River Road, Building 302 (ESB)

Waynesboro, GA 30830 Bin 6031 Waynesboro, GA 30830 Mr. Wayne Guilfoyle Commissioner District 8 Augusta-Richmond County Commission 4940 Windsor Spring Rd Hephzibah, GA 30815 Gwendolyn Jackson Burke County Library 130 Highway 24 South Waynesboro, GA 30830 Mr. Reece McAlister Executive Secretary Georgia Public Service Commission Atlanta, GA 30334 Page 1 of 3

Vogtle Mailing List Email aagibson@southernco.com (Amanda Gibson) acchambe@southernco.com (Amy Chamberlian) awc@nei.org (Anne W. Cottingham) becky@georgiawand.org (Becky Rafter) bhwhitley@southernco.com (Brian Whitley)

Bill.Jacobs@gdsassociates.com (Bill Jacobs) corletmm@westinghouse.com (Michael M. Corletti) crpierce@southernco.com (C.R. Pierce) dahjones@southernco.com (David Jones) david.hinds@ge.com (David Hinds) david.lewis@pillsburylaw.com (David Lewis) dlfulton@southernco.com (Dale Fulton) ed.burns@earthlink.net (Ed Burns) edavis@pegasusgroup.us (Ed David)

G2NDRMDC@southernco.com (SNC Document Control)

George.Taylor@opc.com (George Taylor) harperzs@westinghouse.com (Zachary S. Harper) james1.beard@ge.com (James Beard)

JHaswell@southernco.com (Jeremiah Haswell) jim@ncwarn.org (Jim Warren)

John.Bozga@nrc.gov (John Bozga)

Joseph_Hegner@dom.com (Joseph Hegner) karlg@att.net (Karl Gross) kmstacy@southernco.com (Kara Stacy) kroberts@southernco.com (Kelli Roberts)

KSutton@morganlewis.com (Kathryn M. Sutton) kwaugh@impact-net.org (Kenneth O. Waugh) markus.popa@hq.doe.gov (Markus Popa) mdmeier@southernco.com (Mike Meier) media@nei.org (Scott Peterson)

Melissa.Smith@Hq.Doe.Gov (Melissa Smith) mike.price@opc.com (M.W. Price)

MKWASHIN@southernco.com (MKWashington) mphumphr@southernco.com (Mark Humphrey)

MSF@nei.org (Marvin Fertel) nirsnet@nirs.org (Michael Mariotte)

Nuclaw@mindspring.com (Robert Temple)

Paul@beyondnuclear.org (Paul Gunter) pbessette@morganlewis.com (Paul Bessette) ppsena@southernco.com (Peter Sena,III) r.joshi15@comcast.net (Ravi Joshi) rwink@ameren.com (Roger Wink) sabinski@suddenlink.net (Steve A. Bennett) sara@cleanenergy.org (Sara Barczak)

Page 2 of 3

Vogtle Mailing List sblanton@balch.com (Stanford Blanton)

Shiva.Granmayeh@hq.doe.gov (Shiva Granmayeh) sjackson@meagpower.org (Steven Jackson) sjones@psc.state.ga.us (Shemetha Jones) skauffman@mpr.com (Storm Kauffman) slieghty@southernco.com (Steve Leighty) sroetger@psc.state.ga.us (Steve Roetger) syagee@southernco.com (Stephanie Agee)

TomClements329@cs.com (Tom Clements)

Vanessa.quinn@dhs.gov (Vanessa Quinn) wayne.marquino@gmail.com (Wayne Marquino) weave1dw@westinghouse.com (Doug Weaver)

William.Birge@hq.doe.gov (William Birge)

X2edgran@southernco.com (Eddie R. Grant) x2gabeck@southernco.com (Gary Becker)

X2hagge@southern.com (Neil Haggerty)

X2wwill@southernco.com (Daniel Williamson)

Page 3 of 3

U.S. NUCLEAR REGULATORY COMMISSION REGULATORY AUDIT OF VOGTLE ELECTRIC GENERATING PLANT UNITS 3 AND 4 LICENSE AMENDMENT REQUEST LAR-19-014 TORNADO MISSILE PROTECTION FOR MAIN STEAM VENT STACKS AND WALL 11 Docket Nos.52-025 and 52-026 I. INTRODUCTION AND BACKGROUND By letter dated August 16, 2019, Southern Nuclear Operating Company (SNC) submitted license amendment request (LAR)19-014, Tornado Missile Protection for Main Steam Vent Stacks and Wall, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19228A240). SNC is the combined license (COL) holder for the Vogtle Electric Generating Plant (VEGP), Units 3 and 4.

In LAR-19-014, SNC requested changes to the evaluation of the auxiliary building main steam safety valve (MSSV) vent stack openings and the auxiliary building Wall 11 openings for protection from tornado-generated missiles. The changes include the evaluation of horizontal missiles targeting the MSSV vent stacks, the evaluation of vertical missiles targeting the MSSV vent stack openings, and the evaluation of missiles targeting the auxiliary building Wall 11 openings. SNC stated that the evaluations demonstrate that the tornado missiles will not prevent safe shutdown and will not result in an offsite release exceeding the limits defined in Title 10 of the Code of Federal Regulations (10 CFR) 50.34.

SNC indicated that the requested amendment requires changes to the licensing basis documents in the form of departures from the plant-specific Design Control Document (DCD) Tier 2 information (as incorporated into the Updated Final Safety Analysis Report (UFSAR) and detailed in Section 2). SNC stated that no change is made to Tier 1, Tier 2*, or COL information; however, SNC stated this change involves a revision to plant-specific Tier 2 information that meets the criteria for a license amendment under 10 CFR Part 52, Appendix D, Section VIII.B.5.b(8) in that it was determined that the proposed change would result in a departure from a method of evaluation described in the plant-specific DCD used in establishing the design bases or in the safety analyses, and thus requires NRC approval for the Tier 2 departures.

To facilitate the evaluation of LAR-19-014, the NRC staff conducted a regulatory audit of the SNC documentation supporting LAR-19-014 from October 9, 2019 to December 5, 2019, including:

  • Review of applicable documents provided by SNC in its electronic reading room (eRR) in support of the proposed changes described in LAR-19-014. The NRC staff conducted telephone conferences with SNC to discuss the specific documents.
  • Determination of the need for any requests for additional information (RAIs) to modify or clarify the information provided in LAR-19-014.

Enclosure

II. PURPOSE AND REGULATORY AUDIT BASES The purpose of this audit was for the NRC staff to examine and evaluate non-docketed information to verify the conclusions in the Request for License Amendment: Tornado Missile Protection for Main Steam Vent Stacks and Wall (LAR 19-014), submitted on August 16, 2019, by SNC, the COL holder for the VEGP Units 3 and 4 (ADAMS Accession No. ML19228A240).

This regulatory audit was based on the following:

  • VEGP Unit 3, Current Facility Combined License NPF-91, revised April 30, 2019, License Condition 2.D.(2)(a) (ADAMS Accession No. ML14100A106).
  • VEGP Unit 4, Current Facility Combined License NPF-92, revised April 30, 2019, License Condition 2.D.(2)(a) (ADAMS Accession No. ML14100A135).
  • NRO Office Instruction NRO-REG-108, Revision 0, Regulatory Audits III. NRC AUDIT TEAM Thomas G. Scarbrough, Senior Mechanical Engineer, NRC Angelo Stubbs, Senior Safety and Plant System Engineer, NRC Pravin Patel, Structural Engineer, NRC Malcolm Patterson, Reliability and Risk Analyst, NRC Billy Gleaves, Senior Project Manager, NRC IV. AUDIT PREPARATION The NRC staff prepared an audit plan (Reference 4) that identified the information needed for this audit. The audit plan requested that specific documentation be made available for the NRC staffs review. SNC made available specific documents in the Westinghouse Electric Company (Westinghouse) eRR.

V. AUDIT SCOPE The primary scope of this audit was the review of the SNC documentation supporting the changes requested in LAR-19-014.

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VI. AUDIT PERFORMANCE The NRC staff conducted an entrance meeting by telephone conference on October 15, 2019, to discuss the audit plan for LAR-19-014. The staff conducted an exit meeting by telephone conference on December 5, 2019, to discuss the results of the audit. The topics addressed during the audit and the results of the NRC staffs review are as follows:

The NRC staff in the Containment and Plant System Branch reviewed Westinghouse documents that support VEGP Units 3 and 4 LAR-19-014. Specifically, the staff reviewed documents that examined the potential effect of tornado generated missiles impacting the main steam vent stacks and auxiliary building Wall 11. These documents were reviewed because they were used to support conclusions in LAR-19-014 on the capability of the MSSVs to perform their safety function during and after a tornado or high winds event.

In its review of the supporting documents, the staff first confirmed that the missiles considered in the analysis were appropriate, in terms of missile type versus energy spectrum, and consistent with Regulatory Guide 1.76, Revision 1, and with the VEGP Units 3 and 4 licensing basis. The staff then reviewed the relevant information on the alternate flow path used if the normal MSSV flow discharge path had become obstructed with the results provided in Attachment A to Westinghouse letter LTR-CRA-15-188, Effect of MSSV Steam Release to MSIV Room due to Tornado Missiles for AP1000 Plant. The staff found information that supported SNCs assertion that in the event that tornado missiles impact the MSSV discharge stacks and crimp the stack, there would be no impact on the overall primary and secondary systems response and that the steam released from the MSSVs would discharge to the main steam isolation valve (MSIV) rooms through the vent stack drip pan area.

The staff specifically reviewed Westinghouse letter LTR-CRA-15-188, which included an evaluation of the potential effect that a blockage of the normal MSSV discharge stacks could have on the MSIV room environment due to MSSV steam released to the room via the alternate steam flow path that will occur if the tornado missile obstructs the normal flow through the MSSV roof vent stack. The licensees analyses of the MSIV compartment pressurization for the most limiting location, the peak differential pressure, of 5.6 pounds per square inch (psi), was below the design pressure of 6.5 psi. Based on review of the supporting documentation examined in this audit the staff found that information supporting the analysis of tornado missiles impacting the MSSV discharge stacks and crimping the stack, supporting the assumption that the steam released from the discharge MSSVs will be discharged into the MSIV rooms through the alternate release path.

In performing the MSSV performance portion of the audit review of LAR-19-014, the NRC staff in the mechanical engineering and inservice testing branch reviewed evaluations and other supporting documentation that demonstrate the qualification of the MSSVs to be in accordance with the American Society of Mechanical Engineers (ASME) Standard QME-1-2007, Qualification of Active Mechanical Equipment Used in Nuclear Power Plants, as accepted in NRC Regulatory Guide 1.100 (Revision 3), Seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Active Mechanical Equipment for Nuclear Power Plants, to be capable for performing their safety functions in consideration of the potential effects of tornado missiles.

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LAR-19-014 specifies that the requested changes will not adversely affect any safety-related equipment, design code, function, design analysis, safety analysis input or result, or design/safety margin. LAR-19-014 also states that there are no changes to the design, setpoints, lift pressure, or relief capacity of the MSSVs. LAR-19-014 indicates that there is no impact to the qualification or design conditions for the MSSVs. In discussions during a public meeting on July 25, 2019, SNC and Westinghouse personnel stated that LAR-19-014 will result in no change to the qualification of the MSSVs in accordance with ASME Standard QME-1-2007 as specified in the plant-specific DCD and VEGP Units 3 and 4 UFSAR.

During the mechanical engineering and inservice testing branchs portion of the audit, the NRC staff reviewed supporting documents for LAR-19-014 made available by SNC in the eRR to verify that the ASME QME-1 qualification for the MSSVs would not be modified by the proposed changes in LAR-19-014. For example, the staff reviewed Westinghouse Engineering & Design Coordination Report (E&DCR) APP-FSAR-GEF-069 for design changes proposed in LAR-19-014, including demonstration that an alternative steam discharge path can be achieved without the availability of the MSSV vent stacks. The staff reviewed Westinghouse document APP-GW-N1-008 for design criteria and guidelines for protection from tornado and hurricane-generated missiles for potential impact on the MSSV performance. The staff also reviewed Westinghouse Calculation Note APP-1241-S3C-004 for the evaluation of the effect of a tornado missile on an MSSV vent arm to demonstrate that the stress generated in the MSSV branch connection will not exceed its yield strength.

Based on its audit review, the staff confirmed that the functional qualification of the MSSVs specified in ASME Standard QME-1-2007 will not be modified by the changes requested in LAR-19-014.

With respect to MSSV backpressure, the NRC staff reviewed supporting documentation for LAR-19-014 in the eRR to evaluate the potential effect on setpoints and capacity of the MSSVs from increased backpressure caused by damage from tornado missiles. In particular, the staff reviewed Westinghouse E&DCR APP-FSAR-GEF-069 and its separate attachment providing an MSSV backpressure calculation in the event that the vent stacks become blocked. The Westinghouse calculations support the statement in LAR-19-014 that the projected increase in MSSV backpressure from crimping of the vent stack caused by a tornado missile would not cause sufficient backpressure to degrade the MSSV capacity. Therefore, the staff confirmed that the proposed changes in LAR-19-014 will not adversely impact the performance of the MSSVs from an increase in backpressure.

Based on the audit review, the NRC staff in the structural branch did not identify any necessary changes to the ASME QME-1 qualification of the MSSVs or adverse impact to the performance of the MSSVs from increased backpressure as a result of tornado missiles as described in LAR-19-014.

In performing the audit review of the LAR, the NRC staff in the structural branch reviewed the licensees evaluation and supporting documentation, APP-2100-CDC-001, Revision 1, Turbine Building First Bay and Auxiliary Building Wall 11 Tornado Missile Barrier Conceptual Design Evaluation, to demonstrate that the new barrier design is in accordance with the AP1000 licensing bases tornado missile parameters and in accordance with the American Institute of Steel Construction (AISC) N690 code. The staff confirmed via email (ADAMS Accession No. ML19295E517) that the design in the document is not conceptual as the document title suggests. The missile angle is considered conservatively at 90 degrees (perpendicular to the barrier). The maximum ductility ratio for all missiles is 0.93, which is less than the required 4

ductility ratio of 1.0. The barrier anchors design will be used per Appendix B of the American Concrete Institute (ACI) 349-01 concrete code. Based on the review of the new barrier design, the staff finds that the calculations supporting the licensing basis support the licensees request that the designed barrier will protect the required safe shutdown equipment.

VII. CONCLUSIONS The NRC staff has reviewed the documentation supporting the SNCs request in VEGP Units 3 and 4 LAR-19-014. The staff has determined that no RAIs are necessary to complete its safety evaluation. Therefore, no open items have been identified that would impact the staff review regarding LAR-19-014.

VIII. SNC AND ASSOCIATED PERSONNEL INTERVIEWED This regulatory audit was completed through access to the Westinghouse eRR and no follow-up regulatory discussions are required to complete the review of LAR-19-014.

IX. DOCUMENTS REVIEWED

1. APP-1241-S3C-004, Tornado Missile Impact Analysis of MSSV Vent Arm, Revision 0, April 30, 2019.
2. Westinghouse Letter LTR-CRA-15-188, Effect of MSSV Steam Release to MSIV Room Due to Tornado Missile for AP1000 Plant, November 17, 2015.
3. APP-FSAR-GEF-069, Class 1 Changes to Tornado and Hurricane Missile Line-of-Sight Evaluation, Barrier Designs and Missile Criteria, Revision 0, August 16, 2019.
4. Westinghouse E&DCR APP-FSAR-GEF-069 Attachment, Assessment of SGS Main Steam Safety Valve Discharging via Vent Stack Drip Plan, undated.
5. APP-2100-GEF-012, Update to the Tornado Missile Line-of-Sight Evaluation Through the Turbine Building & Turbine Building 1st Bay.
6. APP-2100-CDC-001, Turbine Building First Bay & Auxiliary Building Wall 11 Tornado Missile Barrier Conceptual Design Evaluation, Revision 1.
7. APP-2100-GEF-011, Addition of Steel Tornado Missile Barrier in the Turbine Building 1st Bay, EL. 100-0.
8. APP-2131-SS-001, Turbine Building First Bay Structural Steel Tornado Missile Barrier EL 100-0 Section and Details.
9. APP-GW-N1-008, AP1000 Design Criteria and Guidelines for Protection from Tornado and Hurricane-Generated Missiles, Revision 1, September 15, 2016.
10. APP-GW-N4X-001, AP1000 Structures, Systems, and Components Requiring Protection from Externally Generated Missiles, Revision 1, February 13, 2017.

X. REFERENCES

1. Southern Nuclear Operating Company, Vogtle Electric Generating Plant, Units 3 and 4, Request for License Amendment, Tornado Missile Protection for Main Steam Vent Stacks and Wall 11, August 16, 2019 (ADAMS Accession No. ML19228A240).
2. NRC Regulatory Guide 1.76, Revision 1, Design-Basis Tornado and Tornado Missiles for Nuclear Power Plants, March 2007 (ADAMS Accession No. ML070360253).
3. NRO-REG-108, Regulatory Audits, dated April 2, 2009 (ADAMS Accession No. ML081910260).

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4. Plan for Regulatory Audit of Vogtle Electric Generating Plant Units 3 and 4 License Amendment Request LAR-19-014, Tornado Missile Protection for Main Steam Vent Stacks and Wall 11, October 10, 2019 (ADAMS Accession No. ML19282E152).
5. NUREG-2124, Final Safety Evaluation Report related to the Combined Licenses for Vogtle Electric Generating Plant, Units 3 and 4, September 2012 (ADAMS Accession No. ML12271A045).

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