ML20102B143

Special Rept:On 920610,DG 2A Output Breaker Closed, Resulting in Parallel Operation of DG 2A to Sys Grid & Causing DG Trip.Caused by Reverse Power Condition Due to Operator Error.Surveillance Successfully Completed

ML20102B143
Person / Time
Site:	Braidwood
Issue date:	07/14/1992
From:	Simpkin T COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 9207280205
Download: ML20102B143 (2)

Text

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, / \ Cornminw:alth Edis:n f ) 1400 Opus PI:ce FM0elTY EOUTIG l

y Q J Downers Grove,lilincts 60515 ^

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July 14,1992 g g=

m FILE # t Mr. A. Bert Davis i ' f_.~.)

fiogional Administrator \

O.S. Nuclear Regulatory Commission i Region lli 799 Roosevelt Road Gien Ellyn, Illinois 60137

Subject:

Braidwood Station Unit 2 Diesel Generator 2DG01KA Failuro a

- NRQ_Qo_chet.No. 50-457

Reference:

(a) NUREG-1276, Technical Specification (b) May 28,1992, T.W. Simpkin letter to A.B. Davis t> ear Mr. Davis:

Section 4.8.1.1.3 of reference (a) requires that all diesel generator failures, valid or non-valid, be reported to the NRC pursuant to Specification 6.9.2. The

! ene!osure provides the report that addresses one invalid failu s for the 2DG01KA diesel t generator. The criteria used to determine \ aiid tests and failures is taken from section

,i C.2.e of Regulatory Guide 1.108.

Reference (b) is the most recent report addressing diesel generator failures, submitted per Section 4.8.1.1.3. _

Please direct any questions concerning this submittal to this office.

Very truly yours, E

pmE. ANJ T.W. Simpkin Nuclear Licensing Administrator T%: R. Pulsifer - NRR B. Clayton - Rlli Resident inspector - Braidwood

. NRC Document Control Desk K i 672/6 gg72F'M5 9;oy 4 DOL 151932 8 g - A%JCR 05000457 PDR

.t .. . --

I Braldwood Unit 2. Train A Diesel Generator Valid Failure l June 10.1992 l

On Wednesday, June 10,1992 at 0855 hours0.0099 days <br />0.238 hours <br />0.00141 weeks <br />3.253275e-4 months <br /> the Braidwood Unit 2, Train A (2A) I Diesel Generator (DG) was started I ac;ordance with Braidwood Unit 2 Operating i Surveillance Procedure (2BwOS) 8.1.1.2.a-1, Unit Two 2A Diesel Generator Operability l Monthly (Staggered) and Semi-Annual (Staggered) Surveillance, for a semi-arqual i operability run. At CM hours the 2A DG output breaker was closed resulting in the l parallel operation of the 2A DG to the system grid. When the 2A DG output breaker '

was closed the operator noticed that output VARs were high. The operator began reducing output VARs without first placing a load on the 2A DG, Su!asec uently, the 2A DG trip aed due to a reverse power condition caused by operator error. The Shift Superv sor conducted remedial training with the operator involved regarding the purpose of the reverse power trip and the importance of maintaining a load on the DG when the DG output breaker is closed. At 1123 hours0.013 days <br />0.312 hours <br />0.00186 weeks <br />4.273015e-4 months <br />, the same operator restarted the 2A DG in accordance with 2BwOS 8.1.1.2.a-1. The surveillance was successfully completed withcut incident.

This failure of the 2A DG has been determined to be an invalid failure in accordance with Regulatory Guide 1.103 Section C.2.0. This invalid failure does not put the 2A DG on an increased test frequency schedule. The 2A DG is currently on a monthly test frequency.

As of June 18,1992 the 2A DG has bad four valid failures and the Braidwood Unit -

2, Train B (28) DG hac had no valid failures in the last one hundred Braidwood Unit 2 valid DG demands.

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