05000287/LER-1978-004-03, /03L-0:on 780203,valve BS-3 Failed to Open During Operability Test.Caused by Torque Switch Electrical Failure. Switch Replaced & Valve Operability Verified

/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: 05000287/LER-1978-004, Forwards LER 78-004/03L-0 05000287/LER-1978-004-03, /03L-0:on 780203,valve BS-3 Failed to Open During Operability Test.Caused by Torque Switch Electrical Failure. Switch Replaced & Valve Operability Verified
References
LER-78-004-03L, LER-78-4-3L, NUDOCS 8001090537
Download: ML19308B539 (2)

LER-1978-004, /03L-0:on 780203,valve BS-3 Failed to Open During Operability Test.Caused by Torque Switch Electrical Failure. Switch Replaced & Valve Operability Verified

Event date:
Report date:
2871978004R03 - NRC Website

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It failed to open. The failure caused one of the two reactor toisii buildina sprav trains to be inoperable.

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'A DUKE POWER COMPANY 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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