05000296/LER-1981-004-03, Diesel Generator 3A & Breaker 1836 Tripped from Generator Overspeed During Testing.Caused by Vs Relay on Speed Sensing Panel Energizing at Less than 870 Rpm,Closing Breaker 1836

Diesel Generator 3A & Breaker 1836 Tripped from Generator Overspeed During Testing.Caused by Vs Relay on Speed Sensing Panel Energizing at Less than 870 Rpm,Closing Breaker 1836

ML19343D373
Person / Time
Site:	Browns Ferry
Issue date:	04/27/1981
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19343D366	List: 05000296/LER-1981-004, Forwards Updated LER 81-004/03X-1 05000296/LER-1981-004-03, Diesel Generator 3A & Breaker 1836 Tripped from Generator Overspeed During Testing.Caused by Vs Relay on Speed Sensing Panel Energizing at Less than 870 Rpm,Closing Breaker 1836
References
LER-81-004-03X, LER-81-4-3X, NUDOCS 8105040353
Download: ML19343D373 (2)

LER-1981-004, Diesel Generator 3A & Breaker 1836 Tripped from Generator Overspeed During Testing.Caused by Vs Relay on Speed Sensing Panel Energizing at Less than 870 Rpm,Closing Breaker 1836

Event date:
Report date:
2961981004R03 - NRC Website

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Nic FORM 366, UPDATE REPORT - PREVIOUS REPORT DATE 2/3/81 LICENSEE EVETIT REPORT gNTROL BLOCK: l l l

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EVENT DEscalPTION AND PROBABLE CONSEQUENCES h l During refueling operations, diesel generator 3A and bkr 1836 tripped from diesel l

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l generator overspeed~during diesel generator emergency load acceptance test.

gg,3, There was no danger to the health or safet-l g,,,,) l vere no significant resulting events.

I0isJ lof the public. No previous events. Reference T.S. 3.9.C l.

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33 34 36 36 37 40 el 42 43 44 47 cAuSE CESCRIPT ON AND CCRRECTIVE ACTIONS g,, o g lThe VS relay calibration per EMI 72.1 for D/G's A,B,C,D,3B,3C and 3D was completed l

li j i j l3/20/81 and will be calibrated every six months. Relays for D/G's 3C and 3D did not [

m l initially pick up belov 905 rpm. Settings above 910 rpm could possibly prevent the l

g l D/G load bkr from closing. DCR 2242 replaces the existing speed sensing panels.rith j

,,j lmore reliable solid state panels.

L,i4i e0 STA 4 POWER OTHER STATUS DISCO RY DISCOVFRY DESCRIPTION Surveillance test l

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NAVE OF PREPARER 8105 0A 0 353

. Tennessee Valley Authority Fona BF-17 Browns Ferry Nuclear Plant BF 15.2 3/24/81 r--

LER SUPPLEMENTAL INFORMATION BFRO-50 296 / 81004R1 Technical Specification Involved 3.9.C.1 Reported Under Technical Specification 6.7.2.b(2)

Date of Occurrence 1/10/51 Time of Occurrence 1410 Unit 3

Identification and Description of Occurrence:

~

Diesel generator 3A and diesel breaker 1836 tripped from diesel generator over-speed during diesel generator emergency load acceptance test.

Conditions Prior to Occurrence:

Unit 1 at 99%

Unit 2 at 1002 Unit 3 at 02 refueling out. age.

Action specified in the Technical Specification Surveillance Requirements met due to inoperable equipment. Describe.

Technical specification requirements were met.

f Apparent Cause of Occurrence:

VS relay on speed sensing panel SSP 2 energized at less than 870 rpe cle' sing breaker 1836 while frequency was approximately 55Hz and voltage at. 2500V. RHR I

pump 3A breaker closed and the diesel tried to respond and tripped on mechanical overspeed.

Analysis of Occurrenec:

There was no danger to the health or safety of the public, no release of activity.

no damage to the plant or equipment, and no resulting significant chain of events.

Corrective Action

The VS relay calibration per EMI 72.1 for D/G's A, B, C, D, 3B, 3C, 3D was I

completed. The relays will be calibrated every six months per EMI 72.1.

DCR 2242 has been initiated to replace the existing speed sensing panels with more reliable solid state panels. No periodic calibration was required or perforzJd prior to r-the event.

Fanure Data:

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• Retention: Period - Lifetime; Responsibility - Document Control Supervisor

• Revision:

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