ML20248A689

Summary of 890818 Meeting W/Cp&L in Rockville,Md Re Unit 890617 Loss of Offsite Power Event.List of Attendees,Agenda & Presentation Encl

ML20248A689
Person / Time
Site:	Brunswick
Issue date:	09/13/1989
From:	Le N Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8910020286
Download: ML20248A689 (24)

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NUCLEAR REGULATORY COMMISSION r, a WASHINGTON, D. C. 20656 *

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, September 13, 1989 Docket Nos. ' 50-325 1

. and 501324 I FACILITY: BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 Af0 2 LICENSEE: CAROLINA POWR & LIGHT COMPANY (CP&L)

SUMMARY

OF AUGUST 18, 1989 WITH CAROLINA POWER & LIGHT i

COMPANY REGARDING THE UNIT 2 LOSS OF 0FFSITE POWER EVENT.ON JUNE 17 , 1989 General A meeting Carolina was Power heldCompany

& Light on August 18[CP&L) management.1989, in Rockville, Mary The purpose of the meeting was for CP&L management to: (1) brief the NRR management and staff on the findings and status of various corrective actions regarding the June 17,,1989 loss of offsite power at Brunswick Steam Electric Plant, (Brunswick 2), and (,2) convey the role of CP&L corporate management and their willingness perform 4 critical self-assessment and accept management accountability.

A' list of attendees (Enclosure 1) and a meeting agenda and handout of the presentation (Enclosure 2) are enclosed.

Discussion On June 17, 1989, Brunswick Unit 2 experienced a loss of its startup auxiliary transformer (SAT). Consequently, a ten-hour loss of offsite power (LOOP) to the in-plant safety buses followed. Data from the Brunswick PRA show that of the total core damage frequency (CDF), thirty-eight percent was due to LOOP sequences. Thus, the event has received significant CP&L management attention.

CP&L management formed an independent assessment team (IAT) to assess the appropriateness of the plant personnel's response to the event. This ircluded a review of operator actions, implementatica of procedures, and reliability of safety equipment and systems. The IAT was composed of personnel from the CP&L and INP0 organizations.

As presented by the licensee, the major causes for the loss of the SAT were (1) inadequate water drainage for the 4KY bus duct between the SAT and the turbine building, and (2) personnel error on the part of the relay technician in troubleshooting the sensor circuit for the SAT grounding fault annunicator.

Other contributing factors, as determined by the IAT, included deficiencies in relay technician treining and inadequate ground fault alarm procedures.

In addition, the IAT has concluded that the LOOP event was caused by failure of the plant to achieve a reduction in power to a proper operating condition in accordance with the Plant General Manager's instruction and procedures. That would have avoided the need for a reacter scram when both of the recirculation pumps were tripped due to the loss of the SAT. To prevent recurrence of the evert, CP&L stated that the corrective actions, which have been carried out, include inspection, cleaning and repair of the bus duct and T

8910020286 890913 PDR ADDCK 05000324 3 PNU l'

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l briefing by the plant manager to his operations supervisory personnel on l communication and implementation expectations. Details of other long-term and short-term corrective actions are described in the meeting handout (Enclosure 2). This event and lessons-learned also will be communicated to the industry via INP0 communication processes.

During the meeting, a number of HRC staff concerns were raised, which included the following questions:

(1) Has CP&L revised the SAT's grounding alarm procedure to provide control room operators with additional instructions on anticipating actions for SAT failures?

(2) At what point during the event was the SAT declared inoperable? Are there procedures to instruct operators on the operability of trans-formers when trouble alarms are annunciated in the control room?

(3) If a procedure were in place to allow a cross-tie between Unit 1 and Unit 2 emergency buses, would the use of this procedure mitigate the consequences of a loss of offsite power?

The licensee had no immediate answers to the above NRC staff questions. However, CP&L stated that these concerns will be considered along with other on-going corrective actions that are in progress.

During the meeting, the licensee also stated that the transient after the loss  ;

of the SAT was well managed; the availability and reliability of diesel gen-erators, and HPCI and RCIC pumps were well demonstrated. Emergency procedures i were effective, and operators and management performed well. At the end of the l meeting, the NRC staff commended CP&L for having demonstrated proper attention i and support to plant staff in identifying the root causes and for taking i appropriate corrective actions to prevent future recurrence. l i

Original Signed By:  ;

l Ngoc B. Le, Project Manager Project Directorate 11-1 l' Division of Reactor Projects - I/II Office of Nuclear Regulation

Enclosures:

1.. List of Attendees

2. Agenda and Handout cc w/encls: '

See next page MTG.

SUMMARY

BRUNSWICKi l

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Mr. L. W. Eury Brunswick Steam Electric Plant '

Carolina Power A Light Company Units 1 and.2 cc:

Mr. Russell B. Starkey, Jr. Mr. H. A. Cole Project Manager Special Deputy Attorney General Brunswick Nuclear Project State of North Carolina P. D. Box 10429 P. O. Box 629 Southport, North Carolina 28461 Raleigh, North Carolina 27602 Mr. R. E. Jones, General Counsel Mr. Robert P. Gruber Carolina Power & Light Company Executive Director P. O. Box 1551 Public Staff - NCUC Raleigh, North Carolina 27602 P. O. Box 29520 Raleigh, North Carolina 27626-0520 Ms. Frankie Rabon Board of Commissioners P. O. Box 249 Bolivia, North Carolina 28422 -

Resident Inspector U. S. Nuclear Regulatory Commission Star Route 1 P. O. Box 208 Southport, North Carolina 28461 Regional Administrator, Region II

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U. S. Nuclear Regulatory Commission 101 Marietta Street, Suite 2900 Atlanta, Georgia 30323 Mr. Dayne H. Brown, Chief Radiation Protection Branch Division of Facility Services N. C. Department of Human Resources 701 Barbour Drive Raleign, North Carolina 27603-2008 Mr. J. L. Harness Plant General Manager Brunswick Steam Electric Plant P. O. Box 10429 Southport, North Carolina 28461

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,. 6 DISTRIBUTION.FOR.NEETING.SLIOIARY. DATED: August 18, 1989 Facility: Brunswick

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. Local PDR' T.'Murley 12-G-18

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- E. Adensam 14-B-20 P. Anderson 14-B-20 T... Le 14-B-20' OGC. . . 15-B -

~ E. JordanT MNBB-3302-B. Grimes 9-A-2 C. _ Haughney -' 9-A-1.

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Enclosure 1 3 NRC - CP&L MEETING August 18, 1989 NAMES ORGANIZATIONS Tomqy Le NRC/NRR/ Project Manager Lester Misehnema CP&L/ Manager / Transmission Dept.

Eve Fotopoulos SERCH Licensing /Bechtel Russ Starkey CP&L/ Brunswick Project Mgr.

Mike Jones CP&L/ Brunswick Onsite Nuclear Safety Al Cutter CP&L/VP, Nuclear SUCS.

John Kueck CP&L/CNS/ Projects Charles Haughney NRC/NRR/ Chief Events Assessments E. Adensam NRC/NRR/Dir., PDII-1 D. Tondi NRC/NRR/ DEST /SELB S. Varga NRC/DRP A. Thadani NRC/NRR/ DEST G. Lainas NRC/NRR/DRP T. Conlon NRC/RII, Chief, PSS R. Nease NRC/DLPQ/PQEB R. Karsch NRC/NRR/0EAB P. Kang NRR/ DEST /SELB Y. Noguchi ChuBU Electric Power Co.

D. Nelson RII

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CAROLINA POWER & LIGHT. COMPANY REQUESTED MEETING WITH NRC

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SUBJECT-LOSS OF OFFSITE POWER EVENT JUNE 17,1989 -

BRUNSWICK UNIT 2 AUGUST 18, 1989 NRC HEADQUARTERS WHITE FLINT, MARYLAND

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LOSS OF OFFSITE POWER EVENT JUNE 17,1989 BRUNSWICK UNIT 2 INTRODUCTION AL CUTTER PURPOSE INDEPENDENT ASSESSMENT TEAM BACKGROUND. MIKE JONES

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SIMPLIFIED UNIT ELECTRICAL SYSTEM JUNE 17,1989 EVENT MIKE JONES l EVENT DESCRIPTION SAFETY SIGNIFICANCE CAUSES AND CONTRIBUTING FACTORS CORRECTIVE ACTIONS

SUMMARY

AND CONCLUSIONS MANAGEMENT

SUMMARY

RUSS STARKEY

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• ~ PURPOSE ~

• INDEPENDENT ASSESSMENT TEAM (CP&L AND INPO) l l

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PURPOSE

• TO SHARE OUR UNDERSTANDING OF THE EVENT:

• SAFETY SIGNIFICANCE

• ROOT CAUSES

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• TO DESCRIBE THE ROLE OF I

CORPORATE MANAGEMENT AND WILLINGNESS TO -

• PERFORM CRITIChL SELF ASSESSMENTS

• ACCEPT MANAGEMENT ACCOUNTABILITY

• COMMUNICATE LESSONS LEARNED TO THE INDUSTRY

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. m INDEPENDENT ASSESSMENT TEAM

• COMPOSITION

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• 1 - TEAM LEADER - BRUNSWICK ONSITE NUCLEAR SAFETY (OPERATIONS AND NUCLEAR ENGINEERING EXPERTISE)

• 1 - CORPORATE NUCLEAR SAFETY (ELECTRICAL EXPERTISE)

• 1 - HB ROBINSON ONSITE NUCLEAR SAFETY (EVENT ANALYSIS AND INTERVIEW EXPERTISE)

• 1 - BRUNSWICK ONSITE NUCLEAR SAFETY (PLANT ELECTRICAL SYSTEM EXPERTISE)

• 4INPO

• 1 - HPES EXPERTISE

• 1 - TEAM LEADER - OPERATIONS EXPERTISE

• 1 - EVENT ANALYSIS EXPERTISE

• 1 - COMMONWEALTH EDISON - ELECTRICAL CONSULTANT

• MISSION

• INTERVIEW PERSONNEL INVOLVED

• REVIEW DATA AND PLANT INVESTIGATION

• DETERMINE ROOT CAUSES

• MAKE CORRECTIVE ACTION RECOMMENDATIONS

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BACKGROUND SIMPLIFIED UNIT ELECTRICAL SYSTEM e

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• SAT (STARTUP AUXILIARY TRANSFORMER) GROUND ANNUNCIATOR .

• PLANNING AND POWER REDUCTION --

• TROUBLESHOOTING

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= SAT TRIP AND MANUAL SCRAM ~

• PLANT RESPONSE

• RESTORATION OF OFFSITE POWER TO BOP BUSES

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SAFETY SIGNIFICANCE

• MAJOR RISK CONTRIBUTOR

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• KEY ELEMENTS- EFFECTING j RISK

• INITIATOR FREQUENCY l

• DIESEL GENERATOR AVAILABILITY

• RECOVERY OF AC POWER

• HPCl/RCIC AVAILABILITY ,

• SAT FAILURE SIGNIFICANT DUE TO LONG RECOVERY TIME

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SAFETY SIGNIFICANCE (Corr:inued)

• IMPORTANCE OF DG/HPCl/RCIC HAVE BEEN PREVIOUSLYf .

IDENTIFIED BY PRA AND TARGETED FOR IMPROVEMENT BY MANAGEMENT:

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• DISCRETIONARY LCO POLICY

• RELIABILITY IMPROVEMENT

• MANAGEMENT INITIATED IMPROVEMENTS HAVE BEEN EFFECTIVE:

• KEY SAFETY SYSTEMS WERE AVAILABLE

• KEY SAFETY SYSTEM DID SUCCESSFULLY START AND RUN TO MITIGATE THE EVENT

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CAUSES AND CONTRIBUTING FACTORS

• BUS DUCT MAINTENANCE

• RELAY TECHNICIAN TRAINING

• WORK CONTROLS -

SWITCHYARD INTERFACE

• COMMUNICATION DURING EVENT

• DESIGN / PROCEDURE CHANGE PROCESS -

THOROUGHNESS OF ANALYSIS.

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CORRECTIVE ACTIONS COMPLETED e BUS DUCT INSPECTED, CLEANED, AND REPAIRED e PLANT MANAGER BRIEFED OPERATIONS SUPERVISORY PERSONNEL ON )

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COMMUNICATIONS AND IMPLEMENTATION l EXPECTATIONS

• TRAINING CONDUCTED FOR WILMINGTON AREA TRANSMISSION MAINTENANCE ON EVENT AND HIGH RESISTANCE GROUNDING e TRANSIENT ANALYSIS FOR 1B BUS POWERED OFF UAT

• PLANT MANAGER REVIEWED EVENT WITH EACH OPERATING SHIFT l

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. ms CORRECTIVE ACTIONS IN PROGRESS

• EVALUATION OF PLACING 4kv B BUSES ON UAT's

• DEVELOPING PROCEDURE REVISIONS TO ALLOW OPERATION ON UAT

• BUS DUCT DESIGN REVIEW

• DEVELOP TRAINING ON EVENT AND WORK PRACTICES

• REVIEWING CURRENT INTERFACE - WORK CONTROLS FOR SWITCHYARD e TASK FORCE ESTABLISHING CORPORATE CRITERIA FOR SAFETY EVALUATIONS OF PLANT CHANGES

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SUMMARY

AND CONCLUSIONS

• TR NSIENT WAS MANAGED WELL:

• IMPORTANT SAFETY EQUIPMENT PERFORMED AS REQUIRED e EMERGENCY OPERATING PROCEDURES WERE EFFECTIVE

• OPERATORS AND MANAGEMENT SUPPORT SYSTEMS PERFORMED WELL

• VALUABLE INSIGHTS AND LESSONS LEARNED:

• MINIMlZE THE LIKEllHOOD OF RECURRENCE:

• BUS DUCT PERIODIC MAINTENANCE

• ANALYSIS AND PROCEDURE CHANGE TO PREVENT RECIRCULATION PUMP TRIPS ON LOSS OF SAT

• TRAINING

• INTERFACE - WORK CONTROL

• MINIMlZE THE SEVERITY:

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• UAT BACKFEED STREAMLINED

• STATION BLACKOUT PROCEDURES AND TRAINING

• AVAILABILITY OF DGs, HPCI, AND RCIC

• MOST ROOT CAUSES ARE WELL UNDERSTOOD g _-.. .- . . .

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SUMMARY

• TRANSIENT RESPONSE l

• PROVIDED CONFIDENCE (HOWEVER NOT COMPLACENCY)

• EQUIPMENT, PROCEDURES, PERSONNEL FUNCTIONED WELL

• EMERGENCY PLAN RESPONSE -

WELL EXECUTED

+ SAFETY

• MORE SHARPENED FOCUS l

• PERSONNEL SAFETY

• NUCLEAR SAFETY -

HEIGHTENED SENSITIVITY TO:

• LOOP AS CDF PRECURSOR l

• THE HUMAN ASPECTS OF THIS EVENT 1

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SUMMARY

'[ Continued! .

• SWITCHYARD INTERFACE AND CONTROL

• MUST BE ENHANCED I

• RE-EMPHASISE OF CLOSE COMMUNICATION

• MANAGEMENT ROLE IN ROOT CAUSES

• TRAINING

• COMMUNICATION

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