PNO-IV-88-051, failure of Westinghouse DS-416 Electrical Breakers.Failures Could Be Generic Problem.Westinghouse Representatives on Site Observing Testing,Insp & Installation of Subj Breakers

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PNO-IV-88-051:failure of Westinghouse DS-416 Electrical Breakers.Failures Could Be Generic Problem.Westinghouse Representatives on Site Observing Testing,Insp & Installation of Subj Breakers
ML20195D464
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 06/16/1988
From: Hunnicutt D
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
References
PNO-IV-88-051, PNO-IV-88-51, NUDOCS 8806230128
Download: ML20195D464 (2)


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. , * 'h June 16, 1988 PRELIMIN/.,R,v r "ATION OF EVENT OR UNUSUAL OCCURRENCE -- PN0-IV-88-51 This prelih. 'ication constitutes EARLY notice of events of POSSIBLE safety er pu . rest significance. The information is as initially received without ver1. .

i or evaluation, and is basically all that is known by the Region IV stc.. c.i this date.

FACILITY: South Texas Project Licensee Emergency Classification:

Houston Lighting & Power Notification of Unusual Event Alert Site Area Emergency Earieral Emergency X Not Applicable

SUBJECT:

FAILURE OF WESTIhGH0VSE 416 ELECTRICAL BREAKERS The licensee has inspected and tested 28 safety-related Westinghouse electrical I breakers, type DS-416, in Unit 1 and found that 2 failed due to burned out I

closing coils and 7 others had mechanical binding problems. The licensee inspected and tested 18 breakers in Unit 2 and found 3 with mechanical binding problems. The problems identified affect the shutting action of the breakers only. All the breakers tested are required to shut after a loss of offsite power. Westinghouse representatives are on site at STP observing the testing, inspection, and installation of the DS 416 breakers. These failures of DS 416 electrical breakers could be a generic problem.

In a related matter, the licensee was testing the breaker associated with the Train "B" of the Essential Cooling Water (ECW) pump. The breaker failed to close. Train "C" of the ECW was out of service due to a pump seal failure.

The licensee replaced the failed breaker in Train "B" with the operable breaker in Train "C". The plant is now in a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action statement.

Region IV and NRR, are following the licensee's actions and plant status.

Neither the licensee nor the NRC plans to issue a press release.

CONTACT: DoyleHunnicutt(FTS 728-8137) l l

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DISTRIBUTION:

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