ML19317F466

RO 270/76-14:on 761013,reactor Bldg Electrical Penetration WMV-1 Failed.Caused by Cracked Bushing.Bushing Replaced

ML19317F466
Person / Time
Site:	Oconee
Issue date:	11/12/1976
From:	DUKE POWER CO.
To:
Shared Package
ML19317F462	List: ML19317F461 ML19317F466
References
RO-270-76-14, NUDOCS 8001140699
Download: ML19317F466 (1)

Text

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Report No.: R0-270/76-14 Report Date: November .12,1976 .

p d Occurrence Date_: October 13, 1976 Facility:_ Oconce Unit 2, Seneca, South Carolina Failure of Reactor Building electrical Identification of Occurrence: penetration WMV-1 c Unit at 60 percent full power Conditions Prior to O__currence:

Description of Occurrence:

On October 13, 1976, while performing monthly SF6 gas pressure tests to it was I verify the integrity of Reactor Building electrical penetrations, determined that penetration WMV-1, a Type A electrical penetration for the 2B1 reactor coolant pump motor, indicated zero pressure. SF6 is used as a quenching agent and is normally maintained at a pump Reactor coolant pressure 2B1 dwas50 secured psig or greater for this type penetration.and the repairs to the penetration were initiate Pursuant to Oconee Technical Specificacion Specification 4.4.1.2.4.a.4.4.1.2.4.b and station procedures, reactor shutdown wa percent per hour forty eight hours after discovery of the defective penetra-tion.

Conformance to the criteria of Oconce Technical Sp cification 4.4.1.2.3 was demonstrated within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of initiation or' shutdown by a

'icak rate test on WMV-2 and reactor shutdown was termir.ated.

Designation of Apparent Cause of Occurrence:

The apparent cause of this occurrence was a cracked bushing in the electrical

,!- penetration on the Reactor Building side allowing SF6 gas to escape.

Analysis of Event _:

Visual inspection indicated that the penetration was leaking only on the Reactor Building side. Additionally, leak tests verified that the outer ceramic bushings were intact and would have provided containment integrity if required. .Therefore, it is concluded that the health and safety of the public were not affected by this occurrence.

Corrective Action _:

The cracked bushing was replaced with the penetration in place and subse-The welding procedure used to repair penetra-quently tested for leakage.

r tions of this type has been revised to replace the purge gas, argon, with

' helium due to helium's superior purging qualities. This will result in a

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shorter repair time. No further corrective action is considered necessary at this time.

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