ML20198G213

Summary of 971118 Meeting W/Duke Energy Corp in Rockville, Md,Re non-vital Electrical Bus,Kxa,Dual Unit Reactor Trip on 970906.List of Meeting Attendees & Licensee Handout Encl

ML20198G213
Person / Time
Site:	Mcguire, McGuire
Issue date:	12/23/1997
From:	Nerses V NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-M99714, TAC-M99715, NUDOCS 9801120273
Download: ML20198G213 (22)

Text

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paatopy 58- Sbf .Pk p' t UNITED STATES NUCLEAR REGULATORY COMMISSIC N l

'h WASHINGTON, D.c. 30eeH001

',,,,,, Decerr.ber 23, 1997 LICENSEE: Duke Energy Corporation FACILITY: McGuire Nuclear Station, Units 1 and 2

SUMMARY

OF NOVEMBER 18,1997 MEETING TO DISCUSS THE SEPTEMBER 6,1997 KXA DUAL UNIT REACTOR TRIP (TAC NOS. M99714 .

AND M99715)

On November 18,1997, members of Duke Energy Corporation (DEC, the licensee) met with the U.S. Nuclear Regulatory Commission (NRC) in Rockville, Maryland, to discuss the ncn vital ,

electrical bus, KXA, dual unit reactor trip. The meeting notice and agenda is provided as Enclosure 1; a list of meeting attendees is provided as Enclosure 2; and the licensee's handout is provided as Enclosure 3.

On September 6,1997, the trip cf an auxiliary supply breaker caused the loss of non vital power to plant components on tnth units, for Unit 1, this resulted in a trip of both main feedwater pumps followed by a main turbine and subsequent reactor trip. For Unit 2, it resulted in the closure of the main steam isolation valves followed by a reactor trip on pressurizer high pressure.

The r6.:, son for the break '

has been determined to be heat build up created by a loose cable connection, actuati. .. oreaker thermal trip. The fact that a non safety related piece of equipment, the non vital electrical bus, led to the simultaneous trip to two nuclear reactor units, brought a great deal of review by licensee and staff.

This meeting was established to discuss the licensee's planned actions that are under evaluation to prevent future occurrences. These actions include:

• Analysis and modification to permit four inverter operation on a single battery e Addition of a ' swing" inverter for periods of Inverter maintenance e Preventive maintenance enhancements for the vital and shared auxiliary control including energized work, if necessary Dp e Re-assignment r4 loads to reduce potential for dual unit trip upon loss of either KXA or KXB

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i e Develop specific Opsrations response procedures for loss of instrumentation l and control buses i Further, the licensee performed an accident precursor calculation and a risk informed review of  !

this event to gain further insights into possible corrective actions.

For the latter review, the licensee performed a calculation to obtain information on the reliability l of the specific system involved and this information was used in the licensee decision to i relocate some of the loads to avoid a double unit trip, l

For the accident precursor calculation, the licensee determined that the particular event was 8x101 per reactor year conditional core damage probability.

G Victor Norses, Senior Project Manager Project Directorate ll 2 Division of Reactor Projects 1/ll Office of Nuclear Reactor Regulation i

Docket Nos, 50 369 and 50 370

Enclosures:

As stated cc w/encls: See next page b

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2 e Develop specific Operations response procedures for loss of instrumentation and control buses Further, the licensee performed an accident precursor calculation and a risk informed review of this event to gain further insights into possible corrective actions.

For the latter review, the licensee parformed a calculation to obtain information on the reliability of the specific system involved and this information was used in the licensee decision to relocate some of the loads to avoid a double unit trip.

For the accident precursor calculation, the licensee determined that the particular event was Ox10 ' per reactor year conditional core damage probability, ORIGINAL SIGNED BY:

Victor Nerses, Senior Project Manager Project Directorate 112 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-369 and 50 370 Distribution See next page

Enclosures:

As stated cc w/encls: See next page To receive a copy of this document, Indicate in the box: "C" = Copy without attachment / enclosure "E" o Copy with attachmentlenclosure "N" = No copy OFFICP. PM:PDil-2 l LA:PDil 2 f D:P,D W GL , l NAME V%ftes:en ]_ LBerry /fk HBerkS) /

gE t/1 1/97 7// //4/97 /2/p/91 / /97 / /97 / /97 l DOCUMENT NAME: G:\MCGUIRE\11 18. SUM OFFICIAL RECORD COPY

McGuire Nuclear Station L

cc:

Mr. Paul R. Newton Mr. Richard M. Fry, Director Legal Department, PBOSE Department of Environmental, 422 South Church Street Health and Natural Resources ,

Charlotte, North Carolina 28242 Division of Radiation Protection 3825 Barrett Drive  ;

County Manager of Raleigh, North Carolina 2760g 7721 Mecklenberg County .

720 East Fourth Street Ms. Kalan E. Long Charlotte, North Carolina 28202 Assistant Attomey General North Carolina Department of Mr. Michael T. Cash Justice Regulatory Compliance Manager P. O. Box 62g McGuire Nuclear Station . Raleigh. North Carolina 27602 Duke Energy Corporation 12700 Hager . erry Road Mr. G. A. Copp

- Huntersville, North Carolina 28078 8985 Licensing EC050 Duke Energy Corporation

! Michael McGarry, Ill, Esquire 526 South Church Street Winston and Strewn Charlotte, North Carolina 28242-0001 -

1400 L Street, NW.

Washington, DC 20005 Regional Administrator, Rogion ll U.S. Nuclear Regulatory Commission Senior Resident inspector Atlanta Federal Center '

clo U. S. Nuclear Regulatory 61 Forsyth Street, S.W., Suite 23T85 Commission Atlanta, Georgia 30303 12700 Hagers Ferry Road Huntersville, North Carolina 28078 Elaine Wathen, Lead REP Planner Division of Emergency Management Mr. T. Richard Puryear 116 West Jones Street Owner's Group (NCEMC) Raleigh, North Carolina 276031335 Duke Energy Corporation 4800 Concord Road Mr H. B. Barron York, South Carolina 2g745 Vice President, McGuire Site Duke Energy Co poration Dr. John M. Barry 12700 Hagers Ferry Road Mecklenberg County Huntersville, North Carolina 28078 Department of Environmental Protection 700 N. Tryon Street Charlotte, North Carolina 28202 p

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MARY DATED DECEMBER 23. 1997 l 14ard Copy ,

messeme n s W eness. eta,M a PUBLIC PD 112 Rdg. (wlencis.1,2,3)

OGC (wlencle.1 & 2) '

ACRS (w/encls.1 & 2)

J. Johnson, Ril (w/encis.1,2,3) ,

V. Norses (w/encis.1,2,3)

E-MailIwiencl. 2 oniv)

L S. Collins /F. Miraglia M. Sykes R. Zimmerman L. Trocine .

B. Boger M. Shuaibi

- H. Berkow W. Burton T. Martin (e-mail to SLM3) M. TschlRz, EDO ,

F. Rinaldi C. Ogle, Ril i L. Berry P. Gill P. Kang S. V. Athavale .

J. Mauck .

J.- Calvo t

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October 30,1997 4

MEMORANDUM TO: Herbert N. Berkow, Director Project Directorate ll 2 Division of Reactor Projects 1/11 FROM: Victor Norses, Senior Project Manager Original signed by:

Project Directorate ll 2 Division of Reactor Projects -1/Il

SUBJECT:

FORTHCOMING MEETING WITH DUKE ENERGY CORPORATION (DEC) ON THE MCGUIRE, UNITS 1 AND 2 DUAL UNIT TRIP DATE & TIME: Tuesday, November 18,1997 10:30 a.m. 1:00 p.m.

LOCATION: U.S. Nuc' ear Regulatory Commission -

One White Flint North, Room 012 B11 11555 Rockville Pike Rockville, Maryland PURPOSE: To discuss the specific aspects of the dual unit trip and DEC's corrective actions.

PARTICIPANTS:' NHQ UTILITY V. Nerses, NRR H. Barron H. Berkow, NRR J. Boyle J. Calvo, NRR K. Caldwell J. Wermlel, NRR A. Bhatnager et al. M. Cash P, Abraham Docket Nos. 50 369 and 50-370

Enclosure:

Agenda cc w/ encl: See next page CONTACT: V. Norses, NRR 301 415-1484

• Meetings between NRC technical staff and applicants or licensees are open for interested members of the public, petitioners, intervenors, or other parties to attend as observers pursuant to " Commission Policy Statement on Staff Meetings Open to the Public" 59 Federal Register 48340, g/20/94.

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l AGENDA -

MEETING WITH NRC AND DUKE ENERGY CORPORATION  !

NOVEMBER 18,1997 Introduction er Basic Sequence Events H. Barron er issues i

er Fixes and Long-Term Enhancements Design and Licensing Basis J. Boyle Conclusion H. Barron 4 e- -,,.c,.----,..,,,-..,-,-,w-w.,.--#, -. .m. .. . . ,... , y ,, ., ., ,.- ,----w--,--

ATTENDEE LlRI MEET 1MG_WIItLDDEEDIERGY_COREDBAIlDRAND NRC IO_D18 CUBS MCGUiRE. UNITS 1 & 2 DUAL UNIT TRIP NOVEMBER 1Rm1997, NAME AFFILIATION Victor Norsec NRC/NRR/McGuire PM Paul Gill NRC/NRR/EELB Peter J. Kang NRC/NRR/EELB S. V, Athavale NRR/DRCH/HICB J. L Mauck NRR/DRCH/HICB Frank Rinaldi NRR/PM Jack Boyle DPCo - McGuire Engr.

Ken Caldwell DPCo McGuire - Engr.

Mike Cash DPCo McGuire Compt. Manager Ashok Bhatnagar DPCo - McGuire Supt. of OPS Jerry Culp DPCo - McGuire OSM P. M. Abraham Duke - PRA H. B. Barron Duke - McGuire Site VP Herb Berkow NRC/NRR/PD ll.2 Jose A. Calvo NRC/NRR/EELB Marvin Sykes NRC/Ril/McGuire Leigh Trocine NRC/OEDO Mohammed Shuaibi NRR/DSSA/SRXB William Burton NRR/DRPM/PECB Enclosure 2

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l Event Description H.B. Barron Event Analysis J.W. Boyle t

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Conclusion H.B. Barron i

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Pre-Trip Alignment 6 1

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Plant Transient i i

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- Sequence of Events l - Unit 1 Load rejection circuit actuation (KXA control power) .

i Feedwater pumps tripped on high discharge pressure Turbine trip due to FWPT trips l

Reactor trip due to turbine trip i

- Unit 2 .

i Main Steam Isolation Valves close (KXA control power) i Reactor trip on high RCS pressure

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Planned Actions Under Evaluation f

l Analysis and modification to permit four inverter operation on l a smgle battery I Addition of a " swing" inverter for periods ofinverter j mamtenance l -

Preventive maintenance enhancements for the vital and shared t

auxiliary control including energized work, if necessary i l Re-assignment ofloads to reduce potential for dual unit trip

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upon loss of either KXA or KXB Develop specific Operations response procedures for loss of l instrumentation and control buses i

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_ . _ _ _ _ _ _ _ _ _ a

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! Event Analysis Dual Unit Trip i

- Grid Response

- Shared System Licensing Requirements Impact on Equipment and Systems i

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Dual Unit Trip l

s Grid Response l

- - Grid is designed to withstand simultaneous loss of both McGuire units

- KXA Dual Unit Trip had no impact on grid stability Dual Unit Trip Experience t

- McGuire Experience i

l Loss of KXA Bus (1997) i l

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• Loss ofInstrument Air (1985)

. - Industry Experience ,

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Dual Unit Trip Shared. System Licensing Requirements

- GDC-5 and RG 1.81 addresses shared load impact on systems

important to safety and ability to safely shut down and cool down the l plant

- Do not apply to the non-vital auxiliary control power system.

l Supplied loads are not required to achieve cold shutdown.

l - Although not a part of the McGuire license basis, the current system 1

design meets intent of RG 1.32 and of Position C.2 of RG 1.81 i

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i Impact on Equipment and Systems i

l Unit 1 Unit 2 l

l Loss of Aux Feedwater Pump Yes No i

Recirculation

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e Loss of RCS Letdown Yes No I

! Loss of Pzr PORV Auto Function Yes Yes i

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Main Steam Isolati n Valve Closure No Yes i

i Loss of Process Radiation Monitors Yes Yes l

Loss of Non-Safety Control Room Yes Yes i

l-Indications 9

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, Impact on Equipment and Systems l

Loss of Auxiliary Feedwater Pump Recirculation - Unit 1 l - Cause l Power loss to non-lE control solenoids for all three ARV pump recire l valves '

! - OperationalImpact Safety functions of ARV pump unaffected ARV pump recirc vrives failed closed and valve indication was lost Turbine Driven ARV pump started from loss of KXA Procedures and training did not address ARV pump impact from loss of i KXA

! - Licensing Basis

• GDC-24: Separation of Protection and Control i

All requirements of GDC-24 were met

- Enhancements ~

Established Operations procedure for loss of ARV Recirculation and l provided immediate training to Operators Evaluating replacement of ARV recire valves with auto recire control I valves 10 i

4

Impact on Equipment and Systems i

Loss of Letdown Unit 1

- Cause Loss of control power to nonnal and excess letdown throttle valves

- OperationalImpact l Loss of normal Pzr level control

! Potential to over fill Pzr in prolonged letdown loss l - Licensing Basis l Branch Technical Position 5.1: Ability to cooldown and borate without i

letdown i Ability to cooldown and borate unaffected j - Enhancements

! Evaluate alternative means of establishing Reactor Coolant letdown

! following loss of power I

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l Impact on Equipment and Systems I -

Loss of Pzr PORV Auto Function - Units 1 and 2

- Cause Loss of power to Pzr PORV auto control permissives

- OperationalImpact Loss of Pzr PORV auto control function l Manual control of Pzr PORVs from control room was unaffected and fully l

available. Emergency procedures provide direction for manual control.

l

• Low Temperature Overpressure Protection (LTOP) function was unaffected l

i and fully available P7r PORV position indication and annunciators were unaffected. i j

- Licensing Basis j G.L. 90-06: PORV mitigation for Tube Rupture and LTOP i

! Manual control for SGTR and LTOP function unaffected

! - Enhancements i

j Procedures revised to include Pzr PORV operability information with loss of power l 12 4

r Impact on Equipment and Systems i

Main Steam Isolation Valve Closure Unit 2

- Cause Loss of safety to non-safety interfacing relay power caused all four MSIVs to fail to their safety closed position.

- Operationallinpact i Safety functions of MSIVs were unaffected l Steam dump to condenser unavailable due to loss of steam flow path j Steam release controlled per procedure using Main Steam PORVs and safety valves

- Licensing Basis GDC -24: Separation of Protection and Control ~

All requirements of GDC-24 we.e met 13

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Impact on Equipment and Systems Loss of Process Radiation Monitoring - Units 1 and 2 l - Cause j Loss of power supply to selected rad monitors and associated annunciators

! - OperationalImpact

! All rad monitor Tech Spec required control functions occurred as required l Units I and 2 containment pressure increase due to secured air release 1 l Turbine building sump pumps secured presenting inventory control j problems

! - Licensing Basis EMF 51 "Hi Containment Monitor" is designed for post LOCA monitoring (NUREG 737.TMI Action Plan)

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All monitors that have release interlocks fail safe to terminate release

- EMF 51 did not lose power due to loss of KXA bus. All releases were i

terminated as designed 1

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Impact on Equipment and Systems 4

1 l Loss of Non-Safety Control Room Indications - Units 1 and 2 l -- Cause i

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Loss of KXA resulted directly in loss of some non-safety indicators

- OperationalImpact Control Room indications lost were all non-safety indicators l No loss of any safety related control function l All Operations procedure verification completed within the control room Aggregate effect of lost indication required Operations to find alternate

verifications means for some procedure steps l

- Licensing Basis i GDC-13: Ability to monitor fission process and maintain Reactor Coolant j boundary integrity

No impact to fission process monitonng or any Reactor Coolant boundanes t

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i l Conclusion Effective management of event by C/R operators Low Safety Significance I

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Plant Performance Consistent with Design and Licensing l -

Comprehensive Planned Actions Under Evaluation i

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