ML17291A784

LER 95-007-00:on 950222,emergency Diesel Start Occurred Due to Voltage Transient on BPA Grid.Confirmation Was Received at 17:51 H That Disturbance Had Originated in BPA Grid

ML17291A784
Person / Time
Site:	Columbia
Issue date:	05/05/1995
From:	Foley C WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17291A783	List: ML17291A782 ML17291A784
References
LER-95-007, LER-95-7, NUDOCS 9505100258
Download: ML17291A784 (4)

Text

LICENSEE EVEIcPORT (LER)

I AGILITY NAME (1) DOCKET NUMBER ( ) PAGE (3)

Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 I DF 3 I.TLE (4)

EMERGENCY DIESEL START DUE 'IO VOLTAGE TRANSIENT ON BPA GRID

6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

EVENT DATE (5) LER NUMBER E VIS ION MONTH DAY YEAR FACILITY NAHES 00 CKET NUHBERS(S)

MONTH DAY YEAR YEAR SEQUENTIAL (I NUMBER UMBER 0 5 0 0 0 0 2 2 2 9 5 9 5 0 0 7 0 0 0 5 0 5 9 5 050 0 0 PERATING HIS REPORT 15 SUBMITTED PURSUANT TO THE REQUIREHENTS OF 10 CFR 5: (Ch ec I( one or mo re of the following) (11)

ODE (9)

ONER LEVEL 20.402(b) 20.405(C) 50.73(a)(2)(iv) 73.71(b)

(10) 20.405(a)(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.73(c) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) THER (Specify in Abstract 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) below and in Text, NRC 0.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) orm 366A) 20.405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER ( 12)

TELEPHONE NUMBER AME I REA CODE C.J. Foley, Licensing Engineer -

5 0 9 7 7 4 3 2 5 COMPLETE ONE LINE FOR EACH COHPONENT FAILURE DESCRIBED IH THIS REPORT (13)

'MANUFACTURER EPORTABLE Izjj>;)j CAUSE SYSTEH COHPONENT MANUFACTURER REPORTABLE CAUSE SYSTEH COMPONENT TO NPRDS @%i'::

0 NPRDS C

jI.I'c? ':

(14) EXPECTED SUBMISSION MONTH DAY YEAR SUPPLEMENTAL REPORT EXPECTED ATE (15)

YES (If yes, complete EXPECTED SUBHISSION DATE) X NO TRACT Ilail On February 22, 1995, the WNP-2 reactor was in power ascension following restart from an earlier reactor shutdown. Electrical power was being supplied to the plant from the Bonneville Power Administration (BPA) grid because reactor power levels were below that required to permit synchronizing the WNP-2 generator to the grid. BPA maintenance activities caused a voltage transient on the grid which resulted in a transient reduction of voltage on the WNP-2 safety-related buses. The Emergency Diesel Generators (EDGs) started automatically but the transient was of such short duration that load transfer did not occur and the buses remained energized from the BPA grid. After BPA confirmed that the transient had originated on the grid, reactor power ascension activities were resumed, and the EDGs were secured. The event had no safety significance and is not reportable. A voluntary LER is submitted per NUREG-1022.

9505i00258 'F50505 PDR ADOCK 05000397 S PDR

LICENSEE EVENT REPORT TEXT CONTINUATION AC1L1TY NAME {1) DOCKET NUMBER {2) LER NUMBER {8) AGE {3)

Year umber ev. No.

~

Mashington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 5 007 0 2 OF 3 ITLE {4)

EHERGENCY DIESEL START DUE TO VOLTAGE TRANSIENT ON BPA GRID Ev ntD cri i n On February 22, 1995, the WNP-2 reactor was operating in Mode 2 at approximately 10% power during power ascension following an earlier reactor shutdown. Electrical power was being delivered to WNP-2 from the Bonneville Power Administration (BPA) distribution grid because reactor power levels were below that required to permit synchronization of the WNP-2 generator to the grid. A power transformer at the Priest Rapids hydroelectric power station failed. Due to on-going maintenance activity at the BPA Midway substation, the failure resulted in a voltage transient in the line between the substation and WNP-2, lasting approximately 15 cycles. This transient caused the voltage on the safety-related buses [ES] at WNP-2 to dip below the under-voltage trip relay [RLY] setpoint level for approximately 2 cycles, resulting in automatic start of the Division 1, and Division 2 Emergency Diesel Generator (EDG) units [EK], as was noted in the Control Room at 17;47 hours5.439815e-4 days <br />0.0131 hours <br />7.771164e-5 weeks <br />1.78835e-5 months <br />. The transient was of such a short duration that load transfer did not occur, and the safety-related buses remained energized from the BPA grid.

Immediate orrective Ac ion Confirmation was received at 17:51 hours that the disturbance had originated in the BPA grid, Reactor power ascension activities were resumed, and at 18:19 hours the reactor mode was changed to Mode 1.

The two EDGs were shut down pursuant to normal procedures.

ggoOt',~au e The root cause of this event was an offsite grid voltage transient.

urther E 1 i n and rrective Ac i There were no structures, systems, or components that were inoperable that contributed to the event. All equipment performed normally, and the event was managed effectively by the Control Room Operators.

No corrective actions are required.

ILffiifi The event had no safety significance. All equipment performed per design. The EDGs are not engineered safety features (ESF) at WNP-2, and therefore, the event is not reportable under 10 CFR 50.72{b)(2){ii) or 50.73(a)(2)(iv). A voluntary report is submitted per NUREG-1022.

i LICENSEE EVENT REPORT (

TEXT CONTINUATION AGILITY NAHE (I) OOCKET NUHBER (2) LER NUHBER (B) PAGE (3)

Year umber ev. No.

Washington Nuclear Plant - Unit 2 IS OIOI7 Olo 3 OF 3 ITLE (4)

EMERGENCY DIESEL START DUE TO VOLTAGE TRANSIENT ON BPA GRID imil r Even LER 85-063, "Auto Start of Standby Diesel Generators During RRC Pump Testing Due to BPA Grid Voltage Fluctuations," reports a similar automatic startup of the diesel generator units due to a BPA grid disturbance during operation at low reactor power.

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