ML20078N512

LER83-043/03L-0:on 830914,following Reactor Trip,Flow Control Valve (FCV) Failed to Close Upon Receipt of Feedwater Isolation Signal.Caused by Malfunctioning Solenoid Valve & FCV-1488 Restricted by Antirotation Device

ML20078N512
Person / Time
Site:	Surry
Issue date:	10/14/1983
From:	Joshua Wilson VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
83-070, 83-70, LER-83-043-03L-02, LER-83-43-3L-2, NUDOCS 8310250609
Download: ML20078N512 (4)

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CAUSE OCSCRIPTION AND CORRECTIVE ACTIONS l3 ; o ; ] FCV-1478 failed due to a malfunctioning SOV and FCV-1488 was restricted by an I gi ,,g l anti-rotation device. The cassociated block valves, MOV-FW-154A & B were closed. '

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• ATTACHMENT 1 ,

• - $UARY POWER STATION, UNIT NO. 1 DOCKET NO: 50-280 REPORT No: 83-043/03L-n EVENT DATE: 09-14-83 TITLE OF THE EVENT: FEEDWATER REGULATION VALVES MALFUNCTION

1. Description of the Event On September 14, following a reactor trip from 100% power, it.was observed that Main Feedwater Regulation Valves (FCV-1478 and FCV-1488)did not close when they received a feedwater isolation signal from the Reactor Protection system. Therefore, FCV 1478 may not and FCV 1488 would not have

. fully closed if they had received a safety injection signal. This is a

. non-conservatism with respect to Technical Specification 3.7.A', Table 3.7-3 and is being reported in accordance with Tech. Spec. 6.6.2.b.(2).

2. Probable Consequences and Status of Redundant Equipment The feedwater lines are isolated upon actuation of the Safety Injection System in order to prevent excessive cooldown of the reactor coolant system.

This mitigates the effects of an accident such as steam break which in itself causes excessive cooldown. Feedwater line isolation also reduces the consequences of a steam line break inside the containment, by stopping the entry of feedwater.

If'a Safety Injection had occured, the Main Feedwater pumps would have tripped, and their associated discharge valves woula have closed. Since this provides redundant feedline isolation, the health and safety of the public' would not have been affected.

3. 'Cause The electro-pneumatic transducer for FCV-1478 had malfunctioned and was giving a high demand air pressure to the valve positioner. This caused the positioner to allow high pressure instrument air to the valve diaphragm.

However, this valve is tripped closed by the de-energization of a 3-way solenoid valve downstream of the positioner. When the SOV is de-energized, it should vent the valve diaphragm and close the air supply path, which would allow the valve to close by spring force. Since the valve did close when instrument air was isolated, it appears that the SOV failed to perform its function.

Feedwater regul'ation valve FCV-1488 did not fully close due to mechanical interference caused by a stem anti-rotation device.

4. - Immediate Corrective Action ,

The immediate corrective action was to close the "A" and "B" feedline block valve, MOV's FW-154A and 154B, respectively.

5. Subsequent Corrective Action The E/P transducer for FCV-1478 was replaced and the valve was stroked to verify proper operation. The anti-rotation device FCV-1488 was removed and the valve stroke was re-set. These valves were then tested with trip signals and returned to operable status.

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6. Action Taken to Prevent Recurrence The SOV's will be replaced at the next outage of sufficient duration.

! 7. Generic Implications

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W viro..vtA ELECTRIC AND POWER COMPANY Surry Power Station P. O. Box 315 gQClN gg*}$ Surry, Virginia 23883 00T 1 ' Serial No: 83-070

- Docket No: 50-280 License No: DPR-32 Mr. James P. O'Reilly Regional Pdninistrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30303 Dear Mr. O'Reilly .

Pursuant to Surry Power Statio$1 '1bchnical Specifications, the Virginia Electric and Power Cmpany hereby subnits the follcwing Licensee Event Report for Surry Unit 1.

Reoort Numler Acolicable 'Ibchnical Soecification 83-043/03L-0 T. S. 6.6.2.b(2)

'Ihis report has been reviewed by the Station Nuclear Safety and Operating Carmittee and will be reviewed by Safety Evaluation and Control.

Very truly yours,

.5 rv%

J. L. Wilson

. Station Yanager Enclosure cc: Document Control Desk, UStHC 016 Phillips. Bldg.

Washington, D. C. 20555 DESIGNATED ORIGINAL Certified B7 -

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