05000346/LER-1979-030-03, /03L-0 on 790220:auxiliary Feedwater Valve Could Not Be Closed,Rendering Auxiliary Feedwater Sys 1-1 Inoperable.Caused by Faulty Torque Switch.Heavier Duty Unit Installed & Sys Declared Operable

/03L-0 on 790220:auxiliary Feedwater Valve Could Not Be Closed,Rendering Auxiliary Feedwater Sys 1-1 Inoperable.Caused by Faulty Torque Switch.Heavier Duty Unit Installed & Sys Declared Operable

ML19274E472
Person / Time
Site:	Davis Besse
Issue date:	03/19/1979
From:	Naylor R TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19274E468	List: 05000346/LER-1979-030, Forwards LER 79-030/03L-0 05000346/LER-1979-030-03, /03L-0 on 790220:auxiliary Feedwater Valve Could Not Be Closed,Rendering Auxiliary Feedwater Sys 1-1 Inoperable.Caused by Faulty Torque Switch.Heavier Duty Unit Installed & Sys Declared Operable ML19274E472
References
LER-79-030-03L, LER-79-30-3L, NP-33-79-33, NUDOCS 7903260227
Download: ML19274E472 (2)

LER-1979-030, /03L-0 on 790220:auxiliary Feedwater Valve Could Not Be Closed,Rendering Auxiliary Feedwater Sys 1-1 Inoperable.Caused by Faulty Torque Switch.Heavier Duty Unit Installed & Sys Declared Operable

Event date:
Report date:
3461979030R03 - NRC Website

text

U.S. NUCLE AR REGULATORY COMMISSION NRC FORM 366 (7 77)

LICENSEE EVENT REPORT CONTROL BLOCK:

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00 61 COCKET NL*.'5 ER Ed 63 EVENT DATE 14 75 REPORT DATE 80 EVENT DESCRIPTION AND PROB ABLE CONSECUENCES h l o l 2 l l On 2/20/79 at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> while perf orming surveillance testing, Auxiliary Feedwater i

This rendered AFW Sys-l I (AFW) Valve AF3869 could not be closed by the notor operator.

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l ten 1-1 inoperable and placed the unit in the Action Statement of T.S. 3.7.1.2.

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]72 hours or be in Hot Shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. There was no danger to the I

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(NP-33-79-33)

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33 35 36 31 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTICNS h IThe cause of the occurrence was due to a f aulty torque switch in the notor operator fori i

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TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-79-33 DATE OF EVENT: February 20, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Auxiliary Feedwater (AFW) Systen valve torque switch failed Conditions Prior to Occurrence: The unit was in Mode 1, with Power (!C(I) = 2422, and Load (Gross MWE) = 818.

Description of Occurrence: On February 20, 1979 at 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> while performing Surveillance rest ST 5071.01, " Auxiliary Feedwater System Monthly Test", AFW System Valve AF3869 could not be closed by the motor operator, but could be opened by the motor operator. This rendered AFW System 1-1 inoperable and placed the unit in the Action Statement of Technical Specification 3.7.1.2, which requires two independent steam generator auxiliary feedwater pumps and flowpaths be operable. The Action Statement requires the inoperable system be returned to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in Hot Shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

Designation of Apparent Cause of Occurrence: The apparent cause of the occurrence was due to a f aulty torque switch in the mocar operator for AFW Valve AF3869. The closing torque switch would actuate and prevent the valve from closing with the motor operator.

The valve could be operated manually.

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel.

In the event of an occurrence which required the AFW System, AFW System 1-2 would have fed the af fected steam generator.

Corrective Action

A new torque switch was installed under Maintenance Work Order 79-1558. This torque switch supplied on the vendor's same part number, is of a heavier duty design.

At 1915 hours0.0222 days <br />0.532 hours <br />0.00317 weeks <br />7.286575e-4 months <br /> on February 20, 1979, Surveillance Test ST 5071.01 was performed and AFW System 1-1 was declared operable, removing the unit from the Action Statement of Technical Specification 3.7.1.2.

Failure Data: One previously reported failure of AFW System motor operator torque switches had been reported under Licensee Event Report NP-33-77-83.

LER #79-030