ML17252A188
| ML17252A188 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/03/1975 |
| From: | Stephenson B Commonwealth Edison Co |
| To: | James Keppler NRC/RGN-III |
| References | |
| BBS Ltr. #-577-75 50-249/75-39 | |
| Download: ML17252A188 (2) | |
Text
Com ealth Edison
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- -o::,One F*orial Plata, Chi_cago, Illinois
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- ,.,.,h Address Reply to: Post Office Box 767
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.. rr Chicago, Illinois 60690
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BBS Ltr. #-577-75 Mr. James G. Keppler, Regional Director Directorate of Regulatory OperatiOn-Region III
- u. s. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 6o137 *
{RegliJat~.ry '
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SUBJEx;Ts REPORT OF ABNORMAL OCCURRmCE PER SI!m'ION 6,6;A OF 'fHE TEX:HNICAL SP~IFICATIONS MAIN STEAM LINE DRAIN VALVE MO 3-220-1 OVERLOAD RELAY FAILURE
References:
- 1) Regulatory Guide 3.16 Rev 1 ApPendix A
- 2) Notification of -Region III of U, s. Nuclear Reg\\iJ.atory Conmi.ssion Telephone: R. Kndp, 1710 hours0.0198 days <br />0.475 hours <br />0.00283 weeks <br />6.50655e-4 months <br /> on August.26, 1975 Telegrams J *. Keppler, n;3'7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> on August 27, 1975
- 3) Drawing Number M-345 and.. 12E-3505A Report Number: S0-249/75-39 Report Date: Sept8mber 3, 1975 OccurrenO'e Date: August 26, 1975 Facility:_ Dresden Nuclear Power S~tion, Morris, Illinois IDENTIFICATION OF OOCURRENCE The overload relay ~ripped twice on motor-operated isolation valve 3-220-1, located. inboard on the main steam drain line. This represen~s an abnormal occurrence because the malfunction of this valve could affect primary containment integrity, CONDITIONS PRIOR'.1'1'0 OCCURRENCE Unit-3 was iii the shutdown mode for a refueling outage.
DF.SCRIPl'ION OF OCCURRENCE At approximately 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> on August 14, 1975, valve 220-1 was being functionally tested to evaluate changes which had been made to the torque switch settings.
During the testing the valve tripped. twice,
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.... *-". September 3, 1975 DF.S°f~~ OF APPAREm' CAUSE OF OCCURRENCE (Component Failur~)
_Oxi.lAugust.26 an investigation revealed that the valve motor bad tripped because
- of a defective overload relay* The reJ.ay appeared to be thermally damaged, but the cause of the damage is unknown.
The motor current was measured and found to be within reasonable limi ta*.
- The overload relay was apparently opening in response to normal current loads. The_ relay should not open unless the motor current becomes excessive *
. ANALYSIS OF OCCURRmCE The malf\\mction of valv.e 220-1 bad little safety_ significance. Had the valve tripped during~Teactor. operat~on, the leakage past the ov.:t:t>oax;d valve 220-2 would have.beeri.well*within*Technical Specification limits even in the event of a loss-of-coolant a~!Jid~t. iPlant ~rsoiiriel ahd-~he:wblic were not endangered I
by this occ\\irrence. *. --**'
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- CORREX:TIVE ACTION " * ~ * * / * *,
The overload relay was replaced, and the valve was cycled satisfactorily several tiii:ies.
FAILURE* DATA
- The overload relay is a G.~eral Electric model§CR 124-K028.
'!'his is the first
~t time an overload ~elay has failed on this valve *.
. BBS:EI.S:smp File/NRC ephenson-
. Superintendent