ML20085G835
| ML20085G835 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/01/1974 |
| From: | Eric Thomas TENNESSEE VALLEY AUTHORITY |
| To: | Case E US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8308290420 | |
| Download: ML20085G835 (2) | |
Text
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AK?ORMAL OCCURPR!CE REPOR" Report Iio.: EFAO-50-260/7h23W Report Date: I?ovember 7,1974 Occurrence Date: !!ovecber 1, 1974 Facility: Browns Ferry I!uclcar Plant unit 2 Identification of Occurrence FCV 1-27 main steanline "B" outboard isolation valve failed to close within
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3 to 5 seconds as recuired by the technical specifications.
Conditions Prior to Occu rence The reactor was being shut down and was less than 10-percent power.
Description of Cecurrence While conducting a surveillance test, FCV 1-27 closed in 5.4 seconds.
Designation of Arcarent Cause of Occurrence The exact cause of failure is unknown.
The ncin steam isolation valve dashpots are fitted with a 3/h" auto-ponent flow control valve with nicroneter adjustnent for centrolling the speed of valve closure.
Analysis of Occu rence The inboard isolation valve FCV 1-26 was operable and would have closed within the required W % d a containment icolation cignal occurred.
There were no adverse effects on the health and cafety of the public as a result of this occurrence.
Corrective Action The affected stec=li.e was 4 ediately isolated, and nor al shutdown operationc continued. Following chutdown, the dachpot oil was checked and found to be filled to proper level. A single adjustment of the auto-ponent flow control valve restored the valve clocure tining to acceptable limits.
Failure Data i
t See Abnornal Occurrence Reports: BFAO-50-259/7454W BFAO-50-260/7412W
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BFAO-7438W, unit 1 BFAO-7412W, unit 1 BFAO-742U, unit 1 Valve Data f'
26" main steen isolation valve
. Manufacturer: Atwood and I?orrill Cc=pany l
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Acting Director of Licensing Office of Regulation U.S. Atomic Energy Cormiccion Washington, DC 20545
Dear Mr. Cace:
TECTESSEE VAT.TRI AUTHORITl - BROMIS FERRY IIUCLEAR PIAliT UNIT 2 -
DOC ET I:0. 50-260 - FACILITI OPER/iTII?G LICE:ISE DPR ABUORMAL OCCURPz CE REPORT EFAO-50-260/7423U The encloced report is to provide details concerning FCV 1-27 main sten =line "B" outboard isolation valve which failed to cloco within 3 to 5 ceconds as recuired by the technical specificctions and is nubnitted in accordance uith Appendix A to Regulatory Guide 1.16, Revision 1, October 1973. This event occurred on Browns Ferry I!uclear Plant unit 2 on liovenber 1,1974.
Vcry truly yours, T2EESSEE VALLEY isUTHORITI
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V 8-E. F. Thenas 8
Director of Power Production Enclosure CC (Enclosure):
Mr. Hor an C. Fosc1cy, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, NW., Suite 818 f
Atlanta, Georgia 30303 11 v '- U g
h' 6,h.
p copy sF;NT REGION
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