ML20084H527
| ML20084H527 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/14/1974 |
| From: | Eric Thomas TENNESSEE VALLEY AUTHORITY |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084H530 | List: |
| References | |
| AO-BFAO-7438W, NUDOCS 8305040581 | |
| Download: ML20084H527 (3) | |
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Mr. John _F. O' Leary, Director TN Directorate of Licensin6 l
Office of Regulation 50-259 U.S. Atomic Energy Ccamission Washington,_DC 20545
Dear I/r. O' Leary:
tem 1ESSEE VALLEY AUTHCRITY - EROWNS FERRY HUCLEAR PIAIIT UNIT 1 -
DOCKET I 0. 50-259 - FACILITY OPERATING LICENSE DPR ABHORI?AL OCCURREI:CE REPORT EFAO-743c74 The enclosed report is to provide details concerning a main steamline isolation valve malfunction and is submitted in accordance
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with Appendix A to Regulatory Guide 1.16, Revision 1, Octcber 1973 This event occurred on Ercuns Ferry I!uclear Plant unit 1 on June 6, h
197 Very truly yours, TEMESSEE VALLEY AUTHCPlTY
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E. F. Thomas Director of Power Prcduction Enclosure CC(Enclosure):
Mr. Norman C. Moceley, Director Region II Regulatcry Operations Office, USAEC 230 Peachtree Street,174., Suite 818 Atlanta, Georgia 3C303 V
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Report No.:
BFAO-7438W Report Date: June 14, 1974 Occurrence Date:
June 6, 1974
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Facility: Browns Ferry nuclear Plant unit 1 Identification of Occurrence
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d On June 6,1974, main steonline "B" outboard isolation valve FCV l-27 closed
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in 1.7. seconds. The required closing time for this volve is not less than 3 1
cr more than 5 seconds.
y Conditions Prior to Occurrence The reactor was at approximately 70-percent power.
3IV startup test No. 25 x
was in pro 6ress.
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Designation of Arnarent Cause of Occurrence An inspection of the ISIV revealed hydraulic fluid leaking past the lower seals on the velve dashpot cylinder. This resulted in a low fluid level in the dashpot cylinder permitting the valve to close too fast. The cause of the lecking fluid was determined to be a denaged seal.
Analysis of Occu*rence All of the !3IV's vere tested at this time and found to close within the 3-to second range except for the "3" outboerd isolation valve FCV l-27.
A review of the transient trace nunber 137 showed the powcr increese experienced with the
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slightAy faster closure of FCV 1-27 was appro::ime.te17.3,0 percent.
This was the h
same increase experienced by the closure of the other'ESIV's. Therefore, there i
was no unsafe operating condition.
L Hn Corrective Action l}
-Immediate corrective action was to shut the in* board isolation velve in the "B" steamline.
At about 1,800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on-June 6, a steen tunnel entry was made and the dashpot on f
131V FCV l-27 was filled with E. F. Ecu~.hton Co. SJ.FE :')620 oil ed the velv
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reset to close in L.7 seconds. This interin corrective e.ction rs to permh several hours of testing to be accon:plished before scheduled roretor trip after which percanent corrective action would be taken. At 2,301 hours0.00348 days <br />0.0836 hours <br />4.976852e-4 weeks <br />1.145305e-4 months <br /> on June 6, the reactor tripped as a result of a startup test.
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i On June 7,new seals were instc11cd in the dachpot cylinder. The cylinder was j
refilled and the valve adjusted to closc s 4.8~ seconds.
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'v' fd Failure Data
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See the following previous abnor.al occurrence reports:
l 1.
Report No. u?AO-742U--Two main steam isolation valves (FCV 1-26 and j
FCV l-51) failed to meet the 3-to-5-second closing time on January 8, 1974, on unit 1.
2.
Report No. 3FAO-7hl2W--:hin steam isolation velve FCV l-27 failed to meet the 3-to-5-second closing time on !.hrch 8, 1974, on unit 1.
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Valve Data:
a 1.
3/4" auto-panent flou control valve, knob-type; auto-ponent drawing Ho. FK-750.
2.
26" main steam isolation valve:
s Manufa:turer: Atrood and :7.orrill Concary Salen, Massachusetts l
Valve Drawing Ho.:
20351-E, Sheets 1 and 2.
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