ML20085E972
| ML20085E972 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/30/1975 |
| From: | Gilleland J TENNESSEE VALLEY AUTHORITY |
| To: | Knuth D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML20085E971 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8308180168 | |
| Download: ML20085E972 (6) | |
Text
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W 831 Powar Buil g
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q TENNESSEE VALLEY AUTHORITY e
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CHATTANOOGA. TENNESSEE 374o1 4
478 39@
June 30, 1975 Mr. Donald F. Knuth, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Knuth:
BROWNS FERRY NUCLEAR PLANT UNIT 3 - REPORTABLE DEFICIENCY -
CORE SPRAY INBOARD INJECTION VALVE - IMPROPERLY WIRED MOTOR BRAKE Initial report of the subject reportable deficiency was made to G. R. Klingler, NRC-IE, Region II, on May 29, 1975.
In compliance with paragraph 50.55(e) of 10 CFR Part 50, we submit the enclosed final report of the deficiency.
1 Very truly yours, (b
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J. E. Gilleland Assistant Manager of Power f
Enclosure i
CC (Enclosure):
Mr. Norman C. Moseley, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II - Suite 818 230 Peachtree Street, NW.
Atlanta, Georgia 30303 i
8308180168 750717 PDR ADOCK 05000296 S
PDR 4
An Equal Opportunity Employer
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r O-O ENCLOSURE BRONUS FERRY UUCLEAR PIlMr UNIT 3 IMPROPERLY WIPID MOTOR BPAIG CORE SPRAY IHBOARD IUJECTION VALVE FCV-3-75-53 DDN 214 FINAL REPORT On May 29, 1975, an initial report was made by telephone to NRC Region II Inspector G. R. Klinger by T. W. Barkalow, R. D. Bradley, and L. W. Elevins.
The initial report was made in compliance with 10CFR50 55(c).
This is the final report for.this occurrence.
Description of Occurrence While performing preoperational test G-12,. core spray inboard injection valve FCV-3-75-53 locked in midstroke and would not move open or closed.
It was then discovered that the valve brake solenoid was smoking heavily.
An inspection later that day revealed that the valve solenoid-operated brake wires had been irmroperly connected to the motor.
The remaining core spray injection line valves (including these on Units 1 and 2) verc cxemined.
No deficiencies were found in the valves on Units 1 and 2.
Houever, the other three valves on Unit 3 (FCV-3-75-23, -25, and -51) were also found to have solenoid wires inproperly connected to the inotor.
cause of Deficiency The valves were improperly connected by the manufacturer.
Attached to this report are Figures 1 and 2.
Figure 1 shows how valve FCV-3-75-53 was wired.
It ecn be seen that the motor was vired for 480 volts, 3 phase, but the brake was connected with two "Y" connections in paranel (a 240-volt, 3-phase arrangement).
Thus the brake was receiving 480 volts, 3 phase, on a 240-volt scheme.,
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Figure 2 shows hew valve FCV-3-75-23, -25, and -51 were connected between the motor windings.
This arrancement allowed too much current through the motor windings.
Safety Implications The core spray system is one of the core standby cooling systems, thus making l
it a safety.related system. All of the brake solenoid circuits on the four l
core spray injection line valves of Unit 3 were found to be improperly connected.
It is ponnible that au four could have suffered a cormon-mode failure duri ig plant lifetime, if they had not been rewired.
The core spray system has two loops with valves FCV-3 75-51 and -53 on one loop and valves FCV-3-75-23 and -25 on the other. Va3tes FCV-3-75-23 and -51 are normally open and valves FCV-3-75-25 and -53 are nonnany closed.
If in the hig.ly w
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O unlikely event there was a co=on-mode failure and one valve in each loop faiacd in a closed position, the core cpray system would be unavailable for emerp,ency core cooling. IlowcVer, the remaining equip =cnt in the ECCS (RCIC and llTCI) would be available for this function.
Description of Corrective Action The valves were rewired as shown in attached Figure 3 The solenoid on valve FCV-3-75-53 was checked carefully for damace and was found to be in satisfactory condition. All four valves were then tested and proven to Perform as specified.
Means Taken to Prevent a Recurrence The valves were supplied in 1970 by Walworth under a contract with General Electric.
The valve operators were supplied to Ualworth by Limitorque; a division of Philadelphia Gear Company. General Electric has been notified of the deficiencies and will contact Walworth's current owners on. the r.atter.
No other ' valves of this type will be installed in Unit 3 since its construction is nearly finished.
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SUDJECT___. bbl
!4 PHoJCCT_b b i OMPUTED BY DATC CHLCMCO h4 DATE
'j i a To 4 80 Volts gg 1
3 Phase T2 N'
TT5 JT 8 ko T
To To
,I T7#
- I Td T4/
T6 W
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/N
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.BA PU R2 BS 70 Go
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. Figure 1 Wiring C;agram Showing FCV-3-75-53 Before Rewiring.
TO Through T9 Mark Motor Con'aiettions.
RO Throuah 89 Mark B rake Connections i
suu;ccr __DDfL 214 eno;ccr _B.EtiP
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CO M f'UT r o esv L TE CHCCntD Dv DAtt A ^
Tc '.00 Vcits l
A B !Cl 3 Phase
(... _
T2 e
3-FT5
-T8 To 4
To To T4g T6 Y
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B7 g4 P5 R2 BB Bo Bo
~We+ws B6 Bo j,os
,y9 a
Figure 2 Wiring Diagram Showing F CV-3-75-23,-25, &-51 Befo re Rewiring.
TO Through T9,Ma rk Motor Connections.
BO Through B9_ _ Mark Bralye Connections,
s v4..w Dc,...m
.~... - ~--.,---.,~..~.....
evo;ccT._ C C)L 214 eno;tcT _BEbP COMPUTED nY DATE CHECnCD DV DATE
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To 4 80 Vol ts A BTC 3 Phase
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T2 5-TT5 yT8
$::To To/
To a
T7#
%T9 T4,-./
T6
- '5 T3 T1
- B2 B5 BB BO
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B0 go B7 B9 I
B4 86 BI B3 Figure 3 Wiring Diacram Chcwing FC\\'-3-75-23,-25,-51, a-53 Af ter Rewiring.
TO Throu.;h T9 tprk Mc for Ccnn-ctien.<.
Rn Thrntidh TP Ma rk P rak e. CR>a n ct00fm.(