ML20085M227
| ML20085M227 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/17/1974 |
| From: | Eric Thomas TENNESSEE VALLEY AUTHORITY |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085M231 | List: |
| References | |
| AO-BFAO-742W, NUDOCS 8311080132 | |
| Download: ML20085M227 (2) | |
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TENNESSEE VALLEY AUTHOAITY MM CHATTANOOGA, TENNESSEE
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ATW M Mr. John F. O' Leary, Director g % [S :088 Directorate of Licensing
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Office of Regulation 34 u l
U.S. Atomic Energy Co= mission Washington, DC 20545 i
Dear Mr. O' Leary:
l TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT UNIT 1 -
DOCKET NO. 50-259 - FACILITY OPERATING LICENSE DPR ABNOR:RL l
OCCURRENCE REPORT BFAO-742W l
The enclosed report is to provide details concerning FCV 1-26 and FCV l-51 main steam inboard isolation valves which failed to close i
within 3-5 seconds as required by technical specifications which occurred on Browns Ferry Nuclear Plant unit 1 on January 8, 1974, and is submitted in accerdance with Appendix A to Regulatory i
Guide 1.16, Revision 1, October 1973.
f Very truly yours, TENNESSEE VALLEY AUTHORITY 7
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E. F. Tho=as Director of Power Production Enclosure i
CC (Enclosure):
I Mr. Norman C. !!oseley, Director Region II Regulatory Operations Office, USAEC 230 Peachtree Street, NW.
Atlanta, Georgia 30303
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l c1 COPY SENT REGIO I
l 8311080132 740117 i
i QDRADOCK 05000259 i
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ABNORMAL OCCURRDICE REPORT y
Report No.--BFAO-Th2W Beport Date--January 17,197h Occurrence Date--January 8, 1974 Facility--Browns Ferry Nuclear Plant unit 1 Identification of Occurrence J
FCV l-26 and FCV l-51 main steam inboard isolation valves failed to close within 3-5 seconds as required by technical specifications.
Conditions Prior to Occurrence The reactor was operating at a thermal power of1,709 m.
I Description of Occurrence While conducting a required surveillance test FCV l-26 and FCV 1-51 closed in 5 3 seconds and 6.2 seconds, respectively.
t Designation of Accarent Cause of Occurrence The exact cause of failure is unknown. The main steam isolation valve dashpots are fitted with a 3/4" Auto-Ponent Flow Control Valve with micrometer adjustment for controlling the speed of valve closure.
e Analysis of Occurrence The outboard isolation valve FCV was operable and would have closed within the required time had a containment isolation signal occurred.
Corrective Action, A single adjustment of the Auto-Ponent Flow Control Volves restored the valve closure timing to acceptable limits. Surveillance Instruction SI k.7.D.l.b(1) was cetisfactorily performed.
Failure Ihta This type of control valve (Auto-Ponent Flow Control) has no record of previous failure.
Valve Data:
3%" Auto-Ponent Flow Control' Valve, Knob-Type - Auto-Ponent Dreving No. FK-750
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