ML19319B761

RO NP-33-77-40:on 770802,containment Isolation Valve Rc 240A Would Not Stroke When Cycled.Caused by Design Problem Causing Strain on Motor Operator.Hanger Readjusted

ML19319B761
Person / Time
Site:	Davis Besse
Issue date:	08/26/1977
From:	Lingenfelter J, Vallade S TOLEDO EDISON CO.
To:
Shared Package
ML19319B654	List: ML19319B653 ML19319B761
References
NUDOCS 8001270225
Download: ML19319B761 (2)

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• g gat 0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br /> on August 2, 1977, an operator attempted to cycle Pressuri g i ss , ou g lzer Sample Valve RC 240A. for the purpose of obtaining a water sample for [

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NAMt Jacque Lingenfelter/ Susan Vallade PHONE (419J 259-5000, ht. 151 l O 01 27021

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TOLEDO EDISON COMPANY g, DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-40 DATE OF EVENT: August 2, 1977 FACILITY: Davis-Besse Unit 1 IDEYrIFICATION OF OCCURRENCE: Containment Isolation Valve RC 240A was inoperable.

i I Conditions Prior to Occurrence: The unit was in Mode 3, with Power (MRT) = 0, and Load (MWE) = 0.

Description of Occurrence: At 0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br /> on August 2, 1977, an operator attempted to cycle Pressure Sample Valve RC 240A for the purpose of obtaining a water sample for the station Chemistry Laboratory, but it would not stroke. The valve was in-

! operable, placing the unit in Action Statement (b) of Technical Specification 3.6.3.1. In compliance with this Action Statement, RC 240A was closed and power removed at 1245 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.737225e-4 months <br /> on August 2, 1977.

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On August 6,1977 at 1018 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.87349e-4 months <br />, RC 240A was opened to enable station personnel to repair the valve. The second isolation valve for that penetration, RC 240B, 3 was then closed and its power removed until work on RC 240A was completed, also

, s.. / in compliance with Action Statement (b) of Technical Sp-acification 3.6.3.1. .

Designation of Aoparent Cause of Occurrence: There was a design problem with a j

spring hanger installed for thermal expansion which caused the failure of the

motor operator. It was designed with the support on the motor rather than on the piping. This caused a strain on the motor operator which caused the torque switch of the valve operator to prevent operation.

Analysis of Occurrence: There was no danger to the health and safety of the public or to station personnel. From 0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br /> to 1245 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.737225e-4 months <br /> on August 2, 1977, the Safety Features Actuation System would have been able to close RC 240B and thus assure Containment integrity if it was needed. At 1245 hours0.0144 days <br />0.346 hours <br />0.00206 weeks <br />4.737225e-4 months <br />, RC 240A was closed and power removed for further assurance of Containment integrity.

r Corrective Action: The hanger was readjusted, valve otroked successfully, and RC 240A was returecd to service o- August 8, 1977, removing the unit from Action Stat ement (b) of Technical Specification 3.6.3.1. To prevent recurrence, a i change in the spring hanger is being investigated by the architect / engineer,

! Bechtel Power Cornoration.

Failure Data: A different Containment Isolation Valve. CV 5074, was inoperable on July 27, 1977 (NP-33-77-38) due to personnel error.

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