ML20084T760

Ro:On 720909,during Turbine Weekly Check,Turbine Generator Load Mismatch Relay 590-121D Scram on Channel B Did Not Deenergize When Control Valve 4 Closed.Caused by Loose Mounting Bolts on Limit Switch.Bolts Adjusted & Tightened

ML20084T760
Person / Time
Site:	Dresden
Issue date:	09/20/1972
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084T764	List: ML20084T760 ML20084T780
References
NUDOCS 8306240093
Download: ML20084T760 (2)

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i-19 . /s . Glar u n. so itput y Direc oc for teactor Project a D ir e c t ora t " of Lic-nairc' ,

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Thic O to r:ncrt a cradi+ica relatiny to the operatica of t he station in phien a react or protect ion spta (hfS) lir; t t r., It ch on t h e i4 turbir,e cont roi valve un found tu S 2 inoperale, contrary to the require-r ats of Section 3.1 of the Techni.ca l Specif:.ca tiens.

I P!:0HL"" M?D Ji'WSTTrATID'1 The,. reactor uc, in the "run" rodo and operatinr,at 560 IMc on Scpte

• r 9, 1972 '. t 0:00, dit t ha Turbine Paekly Checks,Y vas noted that the turbine p,euerator load uia ".t ch relay (590-121D) scran ca Channel "II" did not deenergine unen the 24 control valve vas closed. When the control valv' inst c i c <.; u r e seloncid operates, it actuates a switch which opens contacts de-energinit ,its El' m relay; this caucca a Channel "B" trip when above 40% power. 1'ending cor rection of the problem, fuee No. 590-72511

, 'h wa s t enoved to act uate c Chanael 'T," acran to natisfy the requirements of Section 3.1 ef the Technical snecificaticus.

ya I nve s t i m t ion of th > swit ch showd tbv the mount ire mb.ol.t.s had. .

1 uniked loe;c .illowinn the witca te hift far encugh so that it could not- he il Tiiun ed b: t he fm,t closure aoleaaie.

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'n  : . ;i t cwtt:b 'a . r i i ' ,+od. ' m. : 2 cc, nnd t ect ed sa tisf actorily .

Tho 1: .si r us .o on the ot her thteo ecm.riu va l.ves u re similarly inspected .

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8306240093 720920 gDRADDCK0500 COPY SENT REGION __

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,5 1:r. A. Gianbus so September 20, 1972 4e ti hoc)N A siullar occm rence un s experfonced on f July 7, 1972 as e::plained in the let.ter to 1;r. Eloc, f rn:a Mr. 'Toz len dat ed July 17, 1972. The correct ive action at that tr..e was to rever::e t i .:_ rc.unt inr, belt , f'ecause of plant co: iLtions at tt ;t u2 e. . i . one of t i. ' _ limit s.titcies had the neunt roversed. During the cu:r<mt a nmca ly , ti:e bolt s uct e adjusted and tightened. Darin;; tt.e n :t ra u.t ennoce car n'e, the limit

> itch r:cuntin; belt s will be icversei a r '. deable nut.- installec. This corrective a tica 1.as already been completed ca Unit 2.

l Sincerely,

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U. P. Worden Superintendent UF1:do

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