ML18038B048

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LER 94-001-00:on 941018,unexpected auto-start of Unit 3 DGs Occurred During Performance of SI Due to Personnel Error. Electrical Maint Personnel Briefed on event.W/941117 Ltr
ML18038B048
Person / Time
Site: Browns Ferry Tennessee Valley Authority icon.png
Issue date: 11/17/1994
From: Hsieh C, Machon R
TENNESSEE VALLEY AUTHORITY
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-001-04, LER-94-1-4, NUDOCS 9411300291
Download: ML18038B048 (22)
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Text

IMPEL' 'Y 1 (ACCELERATED RIDS PRGCESSIX REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9411300291 DOC.DATE: 94/11/17 NOTARIZED: NO FACIL:50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee DOCKET I 05000296 AUTH. NAME AUTHOR AFFILIATION HSIEH,C.S. Tennessee Valley Authority MACHON,R.D. Tennessee Valley Authority RECIPE NAME RECIPIENT AFFILIATION

SUBJECT:

LER 94-001-00:on 941018,unexpected auto-start of unit 3 DGs occurred during performance of SI due to personnel error.

Electrical maint personnel briefed on event.W/941117 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR i ENCL TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc. g SIZE: /+

NOTES RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-4-PD 1 1 WILLIAMS,J. 1 1 INTERNAL: ACRS 1 1 ~e./.ROAB/J3SP 2 2 AEOD/SPD/RRAB 1 1 FILE CENTE~R 02 1 1 NRR/DE/EELB 1 1 /DE/EMEB 1 1 NRR/DORS/OEAB 1' NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRSS/PRPB 2 2 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 NRR/PMAS/IRCB-E 1 1' RES/DSIR/EIB 1 1 RGN2 FlLE 01 1 EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE I J H 2 2 NOAC MURPHY I G A 1 1 NOAC POORE,W. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL"RIDS RECIPIENTS:

PLEASE HELP US TO REDUCE iVASTE! CONTACT THE DOCUWIENT CONTROL DESK, ROOM PI-37 (EXT. 504-2083 ) TO ELDIINATEYOUR NAME FROif DISTRIBUTION LISTS I:OR DOC!.'MEN I'S YOI 'ON"I'EED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 27 ENCL 27

41 Tennessee vattey Aulnority.'ost cx.m Box 2000. Decatur. Atacama 35609 2000 R. D. (Rick) Machon vce pres'xtent, Browns Ferry Nuctear Rant November 17, 1994 U.S. Nuclear Regulatory'Commission 10 CFR 50.73 ATTN: Document Control Desk Washington, D.C. 20555

Dear Sir:

BROWNS FERRY NUCLEAR PLANT (BFN)' UNITS 1q '2~ AND 3 DOCKET NOS ~ 50-259~ 50-260'ND 50-296 - FACILITY OPERATING L1CENSE DPR-33I 52'ND 68 - LICENSEE EVENT REPORT 50-296/94001 The enclosed report provides details concerning an .unexpected auto-start of the Unit 3 diesel generators. This report is submitted in accordance with 10 CFR 50.73(a)(2) (iv) .

Sincerely, R. D. chon Site ce. President Enclosure cc: See page 2

'941}300291 94iii7 05000296 PDR ADOCK S, PDR

it U.S. Nuclear Regulatory Commission Page 2 November 17, 1994 Enclosure cc (Enclosure):

INPO Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, Georgia 30339 Paul Krippner American Nuclear Insurers Town Center, Suite 300S 29 South Main Street West Hartford, Connecticut 06107 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35611 Regional Administrator U.S. -Nuclear Regulatory Commission Region 101 II Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. J. F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852

Ck NRC FORH 366 U.S NUCLEAR REGULATORY IXNHISSION APPROVED BY MB NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH LXCENSEE EVENT REPORT THIS INFORMATION COLLECTION'EQUEST: 50.0 HRS ~

(LER) FORWARD COMMENTS REGARDING BURDEN EST IHATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COMHISSION, (See reverse for required nunber of digits/characters for each block) WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3140-0104), OFFICE OF MANAGEMENT AND BUDGET WASHINGTON DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) PAGE (3)

Browns Ferry Nuclear Plant (BFN) Unit 3 05000296 1 OF 8 TITLE (4) Unexpected Auto-Start of Unit 3 Diesel Generators During the Performance of a SI due to Personnel Error EVENT DATE 5 LER NINBER 6 REPORT DATE 7 OTHER FACILITIES INVOLVED 8 SEQUENTIAL REVISION FACILITY NAHE .NA DOCKET NUMBER MONTH DAY YEAR YEAR HONTH DAY YEAR NUMBER NUMBER FACILITY NAME NA DOCKET NUMBER 10 18 94 94 001 00 11 17 94 OPERATING N

THIS REPORT IS SUBHITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR  : Check one or mor e 11 M(SE (9) 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73 71(b)

~

POWER 20.405(a)(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c) 000 LEVEL (10) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) OTHER 20.405(a)(1)(iii) 50.73(a)(2)(i)(B) 50.73(a)(2)(viii)(A) (Specify in 20.405(a)(1)(iv) 50.73(a)(2)(il) 50.73(a)(2)(viii)(B) Abstract below and in Text, 20.405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x) NRC Form 366A LICENSEE CONTACT FOR THIS LER 12 NAME TELEPHONE NUHBER (Include Area Code)

Clare S. Hsieh, Compliance Licensing Engineer (205)729-2635 COMPLETE ONE LINE FOR EACH C(slPONENT FAILURE DESCRIBED IN THIS REPORT 13 REPORTABLE REPORTABLE CAUSE SYSTEH COMPONEHT MANUFACTURER CAUSE SYSTEH COHPONENT HANUFACTURER TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED 14 EXPECTED HONTH DAY YEAR YES SUBMISSION (If yes, complete EXPECTED SUBHISSION DATE).

X NO DATE (15)

ABSTRACT (Limit to 'l400 spaces, i.e., approximately 15"single-spaced typewritten lines) (16)

On October 18, 1994, at 1657 hours0.0192 days <br />0.46 hours <br />0.00274 weeks <br />6.304885e-4 months <br /> CDT, during the performance of the surveillance instruction (SI) for the Core Spray (CS) System Logic Functional Test Loop II, an unplanned Engineered Safeguard Feature (ESF) actuation occurred when Unit 3 Emergency Diesel Generators 3A, 3C, and 3D automatically fast started from a fast start signal and accelerated to full speed and rated voltage. The fast start signal resulted from an inadvertent actuation of the CS Pre-Accident Signal C logic relay. TVA initiated an incident investigation (II) and reported this event in accordance with 10 CFR 50.73(a) (2) (iv), as an event or condition that resulted in manual or automatic actuation of an ESF. The II has initially determined that the apparent root cause was personnel error due to inadequate self-checking. A human performance evaluation determined that contributing causes -were cramped conditions associated with the tested component and inadequate assessment of the risk associ.ated with a procedure change. TVA will complete awareness training for appropriate electrical personnel and emphasize the Stop, Think, Act, Review program and the "good practice" on circuit conti.nuity measurement. TVA will also evaluate safety system SIs and the 4kV shutdown board compartments to minimize the potential of future ESF actuations.

Cl 0 IQ

NRC FORH 366A U.S. NUCLEAR REGULATORY CQHISSION APPROVED BY (NGI NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATION COLLECTION REQUEST: 50 ~ 0 HRS. FORWARD COHHENTS REGARDING BURDEN EST IHATE TO THE INFORMATION AND 'RECORDS HANAGEHENT LICENSEE EVENT REPORT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, TEXT CONTINUATION DC 20555-0001, AND TO THE PAPERWORK REDUCTION 'ASHINGTON, PROJECT (3150-0104), OFFICE OF MANAGEHENT AND BUDGET, WASHINGTON, DC 20503 FACILITY NAKE DOCKET NIPIBER (2) LER NWER (6) PAGE (3)

YEAR SEQUENTIAL , REVISION (1)'rowne NUMBER NUHBER Ferry Unit 3 05000296 94 001 00 2 of 8 TEXT If more s ace is r uired use additional co ies of NRC Form 366A (17)

PLANT CONDITIONS Unit 2 was defueled for the Unit 2 cycle 7 refueling outage with the fuel pool gates installed following the core offload. Units 1 and 3 were shutdown and defueled. Unit 1'as in lay-up status, and recovery activities were in progress on Unit 3.

ZIo DESCRIPTION OF EVENT A. Event:

On October 18, 1994, at 1657 hours0.0192 days <br />0.46 hours <br />0.00274 weeks <br />6.304885e-4 months <br /> .CDT, TVA was performing Surveillance Instruction (SI) for the Core Spray (CS) [BG] System Logic Functional Test Loop ZZ. While performing this SZ, an unplanned Engineered Safeguard Feature (ESF) [JE] actuation occurred when Unit 3 Emergency Diesel Generators (EDGs) [EJ] 3A, 3C, and 3D automatically fast started from a fast start signal and accelerated to full speed and rated voltage. (EDG 3B did not start because its logic breaker was opened for the monthly operability. surveillance.) The fast start signal resulted from an inadvertent actuation of the CS're-Accident Signal C (PASC) logic relay.

The EDGs did not tie onto their respective 4kV shutdown (SD) boards [EB] because no undervoltage signal existed. The EDGs were allowed to run while a preliminary investigation was initiated to determine the exact cause that actuated the PASC relay.

TVA determined that the relay actuated from a shorted circuit that occurred during a circuit continuity measurement on the CS PAS logic. The most likely cause of the short was .a result of TVA electricians placing one of the test leads, from the continuity measuring instrument on a wrong terminal.

At 1707 hours0.0198 days <br />0.474 hours <br />0.00282 weeks <br />6.495135e-4 months <br />, following verification that there were no other equipment malfunction or activities that could have caused the EDGs to fast start, the EDGs were shutdown and returned to standby readiness.

At 1925 hours0.0223 days <br />0.535 hours <br />0.00318 weeks <br />7.324625e-4 months <br />, TVA made a four-hour notification to the NRC pursuant to 10 CFR 50.72(b)(2)(ii). This event is reportable in accordance with 10 CFR 50.73(a)(2)(iv), as an event or condition that resulted in manual or automatic actuation, of an ESF, including the reactor protection system.

'4 KRC FORM 366A U.S. NUCLEAR REGULATORY CQBIISSIOK APPROVED BY (N(B KO. 3150-0104 (5-92) EXP I RES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY KITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORllARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT LICENSEE EVENT REPORT BRANCH (MNBB 7714), U.ST NUCLEAR REGULATORY COMMISSION, TEXT CONTINUATION KASHINGTON, DC 20555-0001, AND TO TNE PAPERNORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, KASHINGTON DC 20503 FACILITY KAHE (1) DOCKET 'KIÃBER (2) LER NIIIBER (6) 'PAGE (3)

YEAR SEQUENTIAL REVISION NUHBER NUHBER Browns Ferry Unit 3 05000296 94 001 '00 3 of 8 TEXT If more s ce is r uired use additional co ies of NRC Form 366A (17)

On October 19, 1994, TVA convened an incident investigation (II) team to evaluate this event and to determine the root cause and corrective actions. This II is still in progress.

B. Ino erable Structures Com onents or S stems that Contributed to the Event:

None.

C. Dates and A roximate Times of Ma or Occurrences:

October 18, 1994 at 1657 CST EDGs 3A, 3C, and 3D fast started during the CS system logic functional test loop II.

A preliminary investigation was initiated.

October 18, 1994 at 1707 CST EDGs 3A, 3C, and 3D were shutdown and returned to standby readiness.

October 18, 1994 at 1925 CST TVA made a four-hour nonemergency notification to NRC in accordance with 10 CFR 50.72(b)(2)(ii).

October 19, 1994 at 0003 CST TVA completed its preli.minary investigation and resumed the CS system logic functional test.

October 19, 1994 at 0510 CST TVA completed the CS system logic functional test without further incident. An II team was then assembled to perform a more detailed investigation into this event.

D. Other S stems or Seconda Functions Affected:

None.

ED Method of Discove The fast start of the EDGs was identified by the Unit 3 main control room operator (utility, licensed) when alarms indicating the start were received. The start was also verified by the Assistant Unit Operator (utility, unlicensed) at the Unit 3 EDGs buildi go

Cl I HRC FORM 366A U.S. NUCLEAR REGULATORY CQIIISSIOH APPROVED BY NGI NO 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS ~ FORWARD COMMENTS REGARD IHG BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT LICENSEE EVENT REPORT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, TEXT CONTINUATION WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK, REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503 FACILITY NAME (1) DOCKET NUMBER (2) LER HIIHIER (6) PAGE (3)

YEAR SEQUENTIAL REVISION NUMBER NUMBER Browns Ferry Unit 3 05000296 94 '001 00 4 of 8 TEXT If more s ce is r ired use additional co ies of NRC Form 366A (17)

F 0 erator Actions:

None.

G~ Safet S stem Res onses:

None.

III'AUSE OF THE EVENT A Immediate Cause:

The immediate cause of this event was an inadvertent actuation of logic relay PASC which resulted in the automatic start of EDGs 3A, 3C, and 3D. TVA determined that the relay actuated when a short occurred during the continuity measurement on the CS PAS logic circuitry.

B. Root Cause:

The II for this event has initially determined that the apparent root cause was personnel error due to inadequate self-checking.

Self-checking was not applied by the TVA electricians during circuit continuity measurement to ensure that the correct component was tested and that the intended action was correct.

The Digital Volt-Ohm Meter (DVOM) used for the continuity measurement on the CS PAS logic circuitry was incorrectly connected. TVA believes that the electricians placed one of the DVOM test leads on a wrong terminal resulting in a short which caused the PASC relay to actuate. The actuated relay started the EDGs.

Additionally, the DVOM was also incorrectly used. The electricians had set the DVOM in the ohms position (0-200 ohm scale) and left the DVOM in that position to check the circuit continuity. Since the Keithly DVOM that was used for the continuity measurement is capable of providing a short circuit path if left in the ohms scale, the DVOM essentially acted as a jumper between the points connected.

C. Contributin Factors:

As part of the II of this event, a human performance enhancement system evaluation was performed. This evaluation determined that contributing causes to this event were cramped conditions associated with the tested component and inadequate assessment of the risk associated with a procedure change.

0 0 NRC FORH 366A U.S. NUCLEAR REGULATORY CQNISSION APPROVED BY OHB NO 3150-0104 (5-92) I EXP RES 5/31/95 ESTIHATED BURDEN PER RESPONSE TO COHPLY WITH THIS INFORHATIOH COLLECTION REQUEST: 50.0 HRS ~ FORWARD COHHENl'S REGARDING BURDEN ESTIHATE TO THE INFORHATION AND RECORDS HANAGEHEHT LICENSEE EVENT REPORT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COHHISSION, TEXT CONTINUATION lJASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150 0104), OFFICE OF HANAGEHENT AND BUDGET, WASHINGTON DC 20503 FACILITY NAHE (1) DOCKET HLMSER (2) LER RIBBER (6) PAGE (3)

YEAR SEQUENl'IAL REVISION NUHBER NUHBER Browns Ferry Unit 3 05000296 94 001 00 5 of 8 TEXT If more s ce is r uired use additional co ies of NRC Form 366A (17)

In order to perform the SI, the electricians have to open the door to a compartment (4kV SD board 3EC) to access the tested components. The compartment has numerous components that are energized and, actuation.

if improperly contacted, could cause an ESF Additionally, in this event, the SI required the DVOM test leads to be landed on components (PASO test switch and terminal strip 7W) that are not in close proximity to each other.

The PASC test switch is located on the lower door of the compartment. Terminal strip ZW is mounted on the inside surface at the top of the compartment (i.e., ZW was approximately 7 feet above the floor) which hampered its access. The layout of terminal strip ZW, due to the close proximity of the terminalsg may have contributed to the electricians mistakenly placing a DVOM test lead on a wrong terminal when connecting to the terminal strip.

Additionally, the risk and consequence associated with a procedure change were not adequately reviewed or assessed. The SI was recently revised to lift the appropriate leads to prevent the actuation of the PAS initiating relay during the test of the CS logic. While this change lessened the impact on the Unit 3 EDGs operability, it resulted in an additional risk of adding a step (i.e., circuit continuity check) to the SZ which could cause an ESF actuation.

IV. ANALYSIS OF THE EVENT The initiation of the Unit 3 EDGs from the PAS logic is a mode. All circuits performed as would have been required to respond fail safe during a valid accident condition, and there were no operational problems encountered during the EDGs start, run or shutdown.

The EDGs ensure no single credible event can disable the core standby cooling functions or their supporting activities. During this event, Unit 3 was defueled and secondary containment was not required. All safety-related components operated as expected, and there are no nuclear safety implications from the event. Therefore, the safety of the plant, its personnel, and the public was not compromised.

~1 gl I

NRC FORM 366A U.S. NUCLEAR REGULATORY, CQIIISSION APPROVED BY (Nm NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTIOH REOUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT LICENSEE EVENT REPORT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION f TEXT CONTZNUATZON WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AHD BUDGET, WASHINGTON, DC 20503 FACILITY NINE (1) DOCKET HISSER (2) LER NNIBER (6) PAGE (3)

YEAR SEQUENTIAL 'REVISION NUMBER NUMBER

'Browns Ferry Unit 3 05000296 94 001 00 6 of 8 TEXT If more s ace is r uired use additional co ies of NRC Form 366A (17)

V. CORRECTIVE ACTIONS A. Inunediate Corrective Actions:

The CS system logic functional test was stopped. The EDGs were allowed to run while a preliminary investigation of the event was initiated. After verifying that no other activities or ecpxipment malfunctions could have caused the EDGs to start, a work order was issued to attempt to duplicate the relay actuation.

TVA tested various configurations on the connection of the CS PASC logi.c ci.rcuitry and verified that the continuity check steps in the functional test were correct. TVA determined that correct terminal had been connected by the electricians, the PASC if the relay would not have actuated. However, connected at either terminal strip ZW or the PASC test switch, the if a wrong terminal was PASC relay would actuate.

An ZZ of this event was initiated. Electrical maintenance personnel have been initially briefed on this event.

B. Corrective Actions to Prevent Recurrence:

Upon completion of the ZZ, this event, along with the root cause and corrective actions, will be further reviewed with the appropriate electrical personnel. Emphasis will be placed on using the Stop, Think, Act, Review (STAR) program. Additionally, the "good practice" of having the instrument set on the voltage scale first when performing continuity measurements will be specifically addressed during this awareness training.

TVA will evaluate the 4kV SD board 3EC compartment and other simi.lar compartments to determine to minimize the potential for future ESF actuations.

if test connections are needed Additionally, the SZ for the CS system logic functional test and other related safety system SZs will also be evaluated and changed, if needed, to reduce the risk of ESF actuations.

C. Other Actions:

The ZZ of this event i.s still on-going. Zf the results of the ZZ significantly alter the root cause or corrective actions of this event, a supplemental report will be submitted.

NRC FORM 366A U.S. NUCLEAR REGULATORY CQIIISSION APPROVED BY CNS NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT LICENSEE EVENT REPORT BRANCH (HNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, TEXT CONTINUATION IJASHIHGTOH, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET,

'WASHINGTON DC 20503 FACILITY NAME (1) DOCKET HIH(BER (2) LER NIHlBER (6), PAGE (3)

YEAR SEQUENTIAL REVISI OH NUMBER NUMBER Browns Ferry Unit 3 05000296 94 001 00 7 of 8 TEXT If more s ce is r uired use additionat co ies of NRC Form 366A (17)

ADDITIONAL INFORMATION A. Failed Com onents:

None.

B. Previous LERs on Similar Events:

There have been several previous LERs due to inadvertent EDGs starts and inadvertent equipment actuations resulting from electrical shorts. The following LERs were caused by personnel errors:

~ LER 296/87004 discussed an inadvertent EDG start due to an electrical short when the individual connecting the test leads allowed them to contact one another.

~ LER 260/87009 discussed an inadvertent isolation of the Reactor Water Cleanup System when one of the test equipment leads was allowed to slip out and contact the sensing line.

~ LER 259/89014 Rl discussed EDGs starts during surveillance testing when a worker mistakenly landed a wire to a energized CASA-2 terminal.

~ LER 260/93009 discussed a completion of Reactor Core Isolation Cooling logic due to an operator mistakenly reporting a tripped relay.

~ LER 259/94001 discussed auto-starting of Emergency Equipment Cooling Water pump A3 when maintenance personnel placed a jumper in the wrong relay.

TVA recognizes that the corrective actions for the above LERs may have been too narrow in scope. The corrective actions for this LER are intended to evaluate the human performance aspects which may have contributed to inadvertent ESF actuations.

VIZ+ Commitment

1. TVA will complete awareness training for electrical personnel on this event and emphasize the STAR program and the "good practice" on continuity measurement by December 30, 1994.

II 4> P" NRC FORM 366A U S. NUCLEAR REGULATORY CCHIISSION APPROVED BY (Ã8 NO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT LICENSEE EVENT REPORT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COHMISSION, TEXT CONTINUATION WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503 FACILITY NAME (1) DOCKET HINBER (2) LER NINBER (6) PAGE (3)

YEAR SEQUENTIAL REVISION NUHBER NUMBER Browns Ferry Unit 3 05000296 94 001 00 8 of 8 TEXT If more s ce is r uired .use.additional co ies of NRC Form 366A (17)

2. will evaluate the 4kV board 3EC compartment and other similar compartments to determine if test connections are needed TVA SD to minimize the potential for future ESF actuations. This action will be completed by May 31, 1995.
3. The SI for the CS system logic functional test and other related safety system SIs will also be evaluated by June 20, 1995 and changed, if needed, to reduce the risk of ESF actuations.

Energy Industry Identification System (EIIS) system and component codes are identified in the text with brackets (e.g., (XX]).

4l tr.

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