ML20137B466
| ML20137B466 | |
| Person / Time | |
|---|---|
| Site: | Washington Public Power Supply System |
| Issue date: | 12/19/1985 |
| From: | Olson P WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| GO1-85-0029, GO1-85-29, NUDOCS 8601150360 | |
| Download: ML20137B466 (3) | |
Text
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Washington Public Power Supply System 3000 George Washington Way P.O. Box 968 Richland, Washington 99352-0968 (509)372-5000 Ei December 19, 1985 Responds to:
G01-85-0029 Response required by:
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E Mr. J. B. Martin Regional Administrator
'd Nuclear Regulatory Commission Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596
Subject:
NUCLEAR PROJECTS NOS. 1 AND 4 DOCKET NOS. 50-460 & 50-513 POTENTIALLY REPORTABLE CONDITION 10CFR50.55(e)
DRESSER FIGURE 3050 DIAPHRAGM VALVES
Reference:
Telecon, C.R. Edwards, Supply System to R. T. Dodds, NRC, same subject, dated November 19, 1985 In the noted reference, the Supply System informed your office of a potentially reportable deficiency in accordance with the requirements of 10CFR50.55(e).
Attachment A provides a statement of the identified condition and a brief description of our planned actions to correct the identified deficiency.
Based on the construction status at WNP-V4, the Supply System will not be able to issue a final report at this time. An update will be provided at construction restart.
If you have any questions or desire further information, please advise.
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Acting, WNP-1 Program Director (821)
PD0:LCO:llw Attachments cc:
A.D. Edmondson, UE&C (898)
E.C. Haren, UE&C (895)
NRC Document Control Desk, DC g"iBas Bi%ift
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ATTACHMENT A Docket Nos. 50-460 & 50-513 Potentially Reportable Condition per 10CFR50.55(e)
Dresser Figure 3050 Diaphragm Valves DESCRIPTION OF DEFICIENCY The Supply System purchased 546 Figure 3050 diaphragm valves per unit from Dresser Industries. These 1/2 inch to 2 inch valves are primarily used as root valves and vent / drain valves in safety related applications.
Dresser Industries recently notified the Supply System of a possible malfunction in the Figure 3050 Y-pattern diaphragm valves.
Apparently, the disc cap is capable of cocking in the disc guide and wedging.
If this happens the disc could lock in any position from full closed to full open without external indication of the actual valve position.
It has also been reported that these conditions are enhanced with higher operating pressures.
ANALYSIS OF SAFETY IMPLICATION A valve stuck in a closed or partially closed position would interfere with the operation of safety related instrumentation which could affect the safe shutdown of the plant.
CAUSE OF DEFICIENCY As reported by Dresser Industries, unanticipated operating conditions of unequal forces may cause the disc cap to stick in any position, thereby not allowing the disc to move.
CORRECTIVE ACTION Dresser Industries has provided a recommendation for modifying the disc guides to prevent this mode of failure (see attached drawing).
Similar modifications have been made by Cleveland Electric and they have reported no further problems with valves 3/4 inch and larger.
However, after the disc modification had been performed on 1/2 inch valves, these valves were reported to infrequently remain closed with the upper stem raised.
Dresser is currently investigating other options.
The Supply System is currently trying to determine the status of each valve (installed or in warehouse).
The method and type of valve modifications are still under consideration at this time. The corrective actions will be submitted in a subsequent report at construction restart.
ACTION TO PREVENT RECURRENCE Implementation of corrective actions to modify the 546 valves will assure that each valve operates as required.
No further actions are deemed warranted at this time.
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