05000254/LER-1979-042-03, /03L-0:on 791214,while Performing MSIV Closure Timing Surveillance,Ao 1-203-1C Found to Close in 5.2-s. Caused by Varied Speed Control Valve Adjustment on Hydraulic Control Cylinder.Valve Adjusted

/03L-0:on 791214,while Performing MSIV Closure Timing Surveillance,Ao 1-203-1C Found to Close in 5.2-s. Caused by Varied Speed Control Valve Adjustment on Hydraulic Control Cylinder.Valve Adjusted

ML19257B273
Person / Time
Site:	Quad Cities
Issue date:	01/04/1980
From:	Hafera T COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19257B270	List: 05000254/LER-1979-042, Forwards LER 79-042/03L-0 05000254/LER-1979-042-03, /03L-0:on 791214,while Performing MSIV Closure Timing Surveillance,Ao 1-203-1C Found to Close in 5.2-s. Caused by Varied Speed Control Valve Adjustment on Hydraulic Control Cylinder.Valve Adjusted
References
LER-79-042-03L-02, LER-79-42-3L-2, NUDOCS 8001150456
Download: ML19257B273 (2)

LER-1979-042, /03L-0:on 791214,while Performing MSIV Closure Timing Surveillance,Ao 1-203-1C Found to Close in 5.2-s. Caused by Varied Speed Control Valve Adjustment on Hydraulic Control Cylinder.Valve Adjusted

Event date:
Report date:
2541979042R03 - NRC Website

text

NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION (77741 LICENSEE EVENT REPORT CONTROL BLOCK: l l

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lh (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6

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60 61 DOCKET NUMBER 68 69 EVENT OATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l While performing the quarterly MSIV Closure Timing surveillance, procedure QOS 250-4 o

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Main Steam isolation Valve A0 1-203-lC was found to close in 5.2 seconds.

This o

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time exceeded the maximum closure time of 5 seconds for any one MSIV (T.S. 3.7.D.1 l

Table 3.7-1).

The seven remaining r4SIV's were tested satifactorily with the l

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l redundant "C" line valve A0 1-203-2C closing in 4.5 seconds.

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40 el 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i

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The speed control valve adjustment on the hydraulic control cylinder had varied, i i l

thus slowing down the valve travel time. The speed control valve was adjusted to l

shorten the valve closure time. The valve was exercised three times and closed in

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l 4.6 seconds.

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N A*.gE OF PREPARER PHONE:

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LER NUMBER:

LER/R0 79-42/03L-0 li.

LICENSEE NAME: Commonwealth Edison Company Quad-Cities Nuclear Power Station Ill.

FACILITY NAME: Unit One IV.

DOCKET NUMBER: 050-254 V.

EVENT DESCRIPTION

On December 14, 1979, while performing routine test procedure QOS 250-4, MSIV Closure Timing, it was discovered that valve A0-1-203-lC had a closing time of 5.2 seconds.

This time exceeded the maximum closure time of 5 seconds for any MSIV as stated in Technical Specification Table 3.7-1.

The seven remaining MSIV's were tested satisfactorily.

There have been three similar occurrences in which a MSIV failed to close in less than 5 seconds; the most recent of which is reported in LER/R0 79-20/03L-0.

VI.

PROBABLE CONSEQUENCES OF THE OCCURRENCE:

The main steam isolation valves are required to close in less than five seconds to prevent fuel rod rupture in the event of a steam line break outside the containment.

A0 1-203-1C valve is the inboard primary containment isolation valve in the "C" steam line. Because the A0 1-203-2C outboard valve closed in the required time, it would have performed as designed, and isolated the steam line in less than five seconds.

Since this redundant valve was operating properly, safe reactor operation was not af fected as resul t of this occurrence.

Vll.

CAUSE

The cause of this occurrence is designated as equipment failure.

The speed control valve adjustment on the hydraulic control cylinder had varied, thus slowing down the valve travel time.

The control valve is a needle valve that regulates the speed of the hydraulic oil flowing from the bottom to the top of the piston. The piston is attached to the stem of the MSIV to regulate the travel speed of the valve stem.

The speed control unit is manufactured by Flick-Reedy Corp.

Vlli.

CORRECTIVE ACTION

The speed control valve was adjusted to shorten the valve closure time. The valve was retested and closure time was found to be 4.6 seconds.

1747 063