TXX-3633, Interim Deficiency Rept Re Position Indication of EMD Gate Valves Supplied by Westinghouse.Initially Reported on 830125.Affected Valves Modified Per Manufacturer Recommendations.Corrective Actions to Be Complete by 830408
| ML20071C753 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/25/1983 |
| From: | Gary R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, TXX-3633, TXX-36BB, NUDOCS 8303080063 | |
| Download: ML20071C753 (2) | |
Text
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February 25,1983 FB 281983 Txx-3633 e
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yy Mr. G. L. Madsen, Chief Reactor Project Branch 1 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement 611 Ryan Plaza Drive, Suite 1000 Docket Nos.:
50-445 Arlington, Texas 76012 50-446 COMANCHE PEAK STEAM ELECTRIC STATION EMD VALVE POSITION INDICATION QA FILE: CP-83-02, SDAR-102 FILE N0.:
10110
Dear Mr. Madsen:
In accordance with 10 CFR 50.55(e), we are submitting the enclosed report of actions taken to correct a design deficiency regarding the position indication of EMD gate valves supplied by Westinghouse. We previously made a verbal report to your Mr. R. G. Taylor on January 25, 1983.
Supporting documentation is available at the CPSES site for your Inspector's review.
We anticipate completion of the corrective action by April 8,1983.
Very truly yours, 4
RJG:aq l
l Enclosure cc: NRC Region IV - (0 + 1 copy)
Director, Inspection & Enforcement (15 copies)
U. S. Nuclear Regulatory Commission Washington, DC 20555 8303080063 830225 PDR ADOCK 05000445 S
PDR I
7-TXX-3633 February 25, 1983 EMD VALVE POSITION INDICATION DESCRIPTION OF THE DEFICIENCY The manufacturer (W) has advised certain gate valves indicate " closed" prior to the valve disc fully isolating flow.
In these valves, a geared limit switch rotor is set to provide an electrical bypass of the OPEN torque switch at the beginning of the opening stroke.
On the closing stroke, the switch changes state before the flow path is completely blocked. As a result, valve closure is indi-Cdt9d before the flow path is completely stopped.
If the valve were to stop between this setpoint and the full shut position, a flow path through the valve could exist even though a CLOSE indication had been achieved.
SAFETY ANALYSIS Should the valve stall or bind following the premature' indication, the operator would have an inaccurate indication of true valve position. This condition could possibly result in reduced flow during the hot leg (high and low pressure),
alternate cold leg (high pressure), and cold leg (low head) injection.
CORRECTIVE ACTION Affected valves in safety-related applications will be modified in accordance with the manufacturer's recommendations.
DATE OF IMPLEMENTATION All corrective actions should be completed by April 8, 1983.
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