ML19317F944
| ML19317F944 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/20/1976 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19317F945 | List: |
| References | |
| NUDOCS 8002210654 | |
| Download: ML19317F944 (2) | |
Text
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SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 1708 59th Street, Box 15830, Sacramento, Cahfornia 95813;(916) 452 3211 December 20, 1976 g$
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Mr. R. H. Engelken U
Director of Regulatory Operations Oc NRC Operations Office, Region V d O
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Walnut Creek Plaza, Suite 202
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Walnut Creek, California 94596
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Re: Operating License DPR-54 k Docket No. 50-312 Reportable Occurrence 76-17
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Dear Mr. Engelken:
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In accordance with Technical Specifications for Rancho Seco Nuclear Generating Station, Section 6.9.1, and Regulatory Guide 1.16,
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Revision 4, Section C.2.b.2, the Sacramento Municipal Utility District is hereby reporting the following Reportable Occurrence as RO 76-17.
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On November 23, 1976, an attempt was made to perform a quarterly surveillance which involved starting the Reactor Building Spray Pump P-291B from the Control Room safety features panel pushbutton. The operator discovered that the pump would not start on signal and his subsequent investigation quickly led him to the pump breaker. The U
breaker, an I-T-E, 480 volt, K-600 model, had not been completely racked in when the pump had been returned to operational status. To rack in this type of breaker, it must be cranked in far enough for a 1
locking hasp to drop in, permitting the springs to be charged.
In this instance the breaker had not been inserted the full distance, the hasp had not dropped, so the springs were not charged. Upon discovering this situation, the operator immediately cranked the breaker in the final short distance and the breaker properly charged.
Operators are given training in the proper method of racking 1._.
in and out breakers of this type, including the ways to verify that the breaker is in fact operational (checking hasp, hearing springs Zl charge). Apparently these methods were not followed in this case, resulting in a safety features pump being rendered inoperable. The Assistant Superintendent, Nuclear Plant Operations, will insure that proper methods of operation of these breakers are reviewed with plant operators and assure that this problem is highlighted during the operator training program.
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December 20, 1976 Removal of.one loop of the Reactor Building Spray System still leaves greater than 100% capability to cope with Reactor Building pressure transients and to provide iodine removal in case cf an accident. The Reactor Building
- Emergency Cooling System (which was available) provides 100% of this capability, y
while the redundant spray loop still provides 50% capability. The Reactor Building Spray System initiates after a five minute delay for plant protection.
This is acceptable because the spray system is not needed during the early stages of an accident. The B loop would not have actuated automatically after
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the five minute delay, but sufficient time would have existed to locate the breaker problem and correct it, returning the loop to service before it was needed.
There was no transient associated with this occurrence.
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'9 Res ctfully submi a0
- t. m Duane C. Browning, Acting General Manager -
/p/ General Manager Wm. C. Walbridge 1
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Y cs: Director, MIPC (3)
Director, IE (30)
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