ML19317F890
| ML19317F890 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/21/1974 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19317F891 | List: |
| References | |
| 12045, NUDOCS 8002210618 | |
| Download: ML19317F890 (1) | |
Text
T M) S?.Ub SACRAMENTO MUNICIPAL UTILITY DISTRICT C g'G 6201 S Street Box 15830, Sacramento. California 95813; (916) 452-3211
!!ovember 21, 1974
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Director
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Directorate of Licensing
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Washington, D. C.
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U. S. Atomic Energy Co.:nission i (..;,j Q,*
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Dear Sir:
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Re: Operating License DPR-54
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.-I' Docket flo. 50-312 N1 J
I Abnormal Occurrence A0-50-312-74-9 N
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l As defined by technical specifications for the Rancho Seco iluclear Power Station, Section 6.12.28, we are reporting the following abnormal I
occurrence as A0-74-9.
-l At approximately 1530 on ilovember 1,1974, plant personnel who were performing routine surveillance testing of the nuclear service cool-ing water "B" system discovered the flow to be 5500 g.p.m. instead of the technical specification minimum flow of 6000 g.p.m. ~as stated in Section 4.5.1.2D-3.
in the nuclear service cooling water "A" system were operable.The p 1.
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The immediate course of action was to inspect the valve positions v
of the components cooled by the ilSCU system.
Valve NSH-088, the !!SCW flow to reactor building emergency cooling unit B, nas found in a core closed cosition than when it was initially thrcttled during the initial flow balance test.
A careful iv nection reueled Unt the uorm cm e on th? no,ition.adjustrent aandle had ucen due to ficw induced vibration.
A new uorm gear was installed on the operator and an inspection of the other throttle valve showed them to be satisfactory with no apparent wear.
The Plant Review Committee review concluded that corrective action taken up to that time was appropriate.
The committee also recommended installing positive locking pins through the valve body to p
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valve sten from rotating and possibly cause a re-occurrence.revent the The locking devices were installed on all the throttle valves for the emergency cooling units. ~The system shall be tested monthly through January 1975.
If the flow remains as reouired in the technical specifications during these additional tests, then nernal quarterly testing will resume.
Due to the condition of the plant there was no transient associated with this occurrence.
Very truly yours, 8002 210.h[
(o)
. J. Mattimce V
Assistant General Manager and Chief. Engineer y
Enclosure 12045 R. H. Engelken, Region V cc:
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