ML19308B539

LER 78-004/03L-0:on 780203,valve BS-3 Failed to Open During Operability Test.Caused by Torque Switch Electrical Failure. Switch Replaced & Valve Operability Verified

ML19308B539
Person / Time
Site:	Oconee
Issue date:	03/03/1978
From:	Ken Wilson DUKE POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19308B528	List: ML19308B527 ML19308B539
References
LER-78-004-03L, LER-78-4-3L, NUDOCS 8001090537
Download: ML19308B539 (2)

Text

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svtNT cascaierien Ano race Asta causacVENCEs h 17TTI I On February 3.1978, durina a valve operability test. BS-3 was to be closed ;

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m ; accident. It failed to open. The failure caused one of the two reactor toisii buildina sprav trains to be inoperable. However, the other train was  ;

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j lo lil i Soec allowances in T.S. 3.5.3. Therefore, public health and safety were  ;

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. OCONEE UNIT 3 Report No.: R0-287/78-4 Report Date: March 3, 1978 -

Occurrenc e Date: February 3, 1978 Facility: Oconee Unit 3, Seneca, South Carolina Description of Occurrence: 3BS-3, Building Spray Pump Suction Valve Inoperable Conditions Prior to Occurrence: 1007. Full Power

• Description of Occurrence:

On February 3,1978, at 1005, during the performance of PT/3/A/150/15A (valve operational test) 3BS-3 failed to open. The valve was closed in order to-test its ability to assume its post-LOCA position (open) and failed to do so. The valve's torque switch was' replaced and the valve was operable by 1515.

Apparent Cause of Occurrence:

The valve's torque switch evidently failed thereby preventing the valve from properly operating.

Analysis of Occurrence:

The reactor building spray system consists of two separate trains with independent spray headers. The 3BS-3 failure rendered the "A" t ain inoperable, but the other train was available to mitigate the consequences of accidents considered in the FSAR, and the train was returned to service within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> allowed for repair in Technical Specification 3.3.5.

Therefore, the health and safety of the public were not endangered by this incident .'

Corrective Action:

The valve's torque switch was replaced and the valve was verified operable.

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