ML19317F849
| ML19317F849 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/04/1976 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19317F850 | List: |
| References | |
| NUDOCS 8002210591 | |
| Download: ML19317F849 (2) | |
Text
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O SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 1708 59th Street. Box 15830. Sacramento, California 95813!(916)452 3211 March 4,1976 Mr. R. II. Engelken Director of Regulatory Operations NRC Operations Office, Region V r.!
1990 N. California Boulevard Walnut Creek Plaza, Suite 202 Walnut. Creek, California 94596 Re: Operating License DPR-54 Docket No. 50-312 Reportable Occurrence 76-2
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Dear Mr. Engelken:
As defined by Technical Specifications for Rancho Seco NucJear
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Generating Station, Section 6.9.1, and Regulatory Guide 1.16 Revision 4,.
Section C.2.b.2, the Sacramento Municipal Utility District is hereby reporting the following Reportable Occurrence as R0-76-2.
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While performing Procedure SP 203.06B, the Quarterly Surveillance
[mi of the Decay lleat System SFAS Valves, the "B" Emergency Semp Valve IIV-(/
26106 failed to open on signal from the Control Room. The valve was then manually opened for a, portion of the stroke, which apparently alleviated the problem. The valve was then fully opened on Control Room signal and was cycled three times without any binding, stoppage or hesitation noted.
The surveillance was performed February 7, 1976.
f' This emergency sump valve is part of the low pressure injection
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function of the Emergency Core Cooling System. As the Borated Water Storage Tank reaches its low level limit approximately 30 minutes following a loss-of-coolant accidene, an alarm directs the operator to open the emergency sump valves to allow recirculation of coolant collected in the sump back to the reactor vessel.
For HV-26106 the recirculation is routed through the "B" Decay lleat Removal Pump. A redundant sump valve, IIV-26105, provides the identical recirculation capability through the "A" Decay lleat Removal Pump, which assured that no loss of low pressure injection resulted from this occurrence.
It was assumed that the valve.either stuck to its seat or stuck because of overtightened packing. As previously reported in Abnormal Occurrence Report A0-74-2, this valve would not open during a surveillance test performed September 9, 1974. The valve stuck tightly in its seat and had to be jacked open.
It was inspected, returned to service and then was subjected to a testing program lasting several months before resuming the normal quarterly surveillance. All further surveillance tests on this 1
,o
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8 0 02 210 N/
AN ELECTRIC $YSTEM SERVING MORE THAN 600.000 IN THE HEART OF CAttFORNIA
O Mr. R. H. Engelken March 4, 1976 valve were successfully completed prior to February 7, 1976. As a means of assuring that the valve will not experience another failure in the future, HV-26106 will be stroked once monthly for the remainder of Core 1, Cycle 1.
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'1 This will provide valve operation more frequent than quarterly over an extended period of time, after which a determination will be made as to whether surveillance will revert to its quarterly schedule.
The valve is manufactured by Darling Corporation and is a Class I, 18-inch stainless steel valve rated for 300 psig and 3000F.
It is an A461 type 630 valve for an H1150 condition. The packing is 10 rings of asbestos f'
1871 manufactured by J. Crane Company. The valve operator is a Limitorque-type SMD-0-40.
There was no plant transient associated with this occurrenpe.
' Respectfully submitted,
?
m J. J. Mattimoe Assistant General Manager and Chief Engineer i
t' cs: Director, MIPC (3)
Director, IE (30) e s..
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