ML20085A467

Recommends That All ethylene-propylene O-rings Be Replaced W/Silcone O-rings During Next Refueling Outage as Preventive Action for Insulation Deterioration.Steps for Stator Changeout,Maint Checks & Followup Discussed

ML20085A467
Person / Time
Site:	Three Mile Island
Issue date:	03/20/1978
From:	Rogers L BABCOCK & WILCOX CO.
To:	Lawyer L, Geoffrey Miller, Ohanlon J METROPOLITAN EDISON CO.
References
TASK-*, TASK-03, TASK-3, TASK-GB GPU-0392, GPU-392, REM-I-346, SOM-II-126, NUDOCS 8307060512
Download: ML20085A467 (2)

Text

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-Babcock &Wilcox  % ce m o [..

P.O. Bos 1260.Lynchtnas.Va. 24505 TelesAone:(804)334-5111 j ..

March 20,1978 I

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• 3064-II-126 - -

Mr. L. L. Lawyer -

i Manager, Generatier. Cperations .

Metropolitan Liiso: company -

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Post Office Box Sh2 * '

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Reading, PA 19603 -

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r Mr. 'G. P. Miller '. .' ':

F Station Superintende=t - -

Hetropolitan Ediscs cn=pany * *

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"Middletown, PA 1TC57 .

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Mr. J. P.. O'Hanlom , ' ". ' ' ' . . E

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Superintendent, Unit I ,

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Post Office Box 480 . <.? ,

Middletown, PA 17067. .

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Subject:

CRDM St tor o Ring Replacement

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.c5 Operating experience at so=e 3&W plants has shown th..c the ' control ~ rod . * ".,- * " , , ,

drive stator ethyle.e-propylene e-rings =ay take a persanent set and  ;-

p crack after so=e pe.riod of ti=e ':his condition could violate the sealing . r.

capability and allov =misture to enter the stator ' cavity. , This moisture*-- @

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. could lead to a deterioration of the insulation and eventual stator.

E failure.

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Investi6ation by Babcock & Vilcox/Dia=ond has determined ~ thaf. a silic'onc. - . .

o-ring vill have a Insger service life. Although our investigation is.

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continuing, ve aie reco:=ending that all ethylene-propylene o-ringste -

4-replaced vith silie==e o-rings during your next refueling outage. . This .

is a precautionary =casure since a non-se=. ling.o-ring by itself does cot .

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. cause a stator failure, however, the cochination of a systen. leak or spill' , ,

I and a faulty o-ring can lead to a stator failure. - . . , . -

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C- 00 8307060512 780320 .-

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PDR ADOCK 05000289 -

' Deft: Eth. Forin 1O q - <.

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. Chirles Shapiro CQ 00'yle ReportingInc.

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• L. L. Lawyer -

G. P. Hiller .

3/20/78 J. P. O'Hanloc' . ,

Attachments I, II, and III give the general procedures for Pre-installation

' Preparation, Vacu=s Drying of Stators, and Pre-installation Precautions.

. The steps to be followed during stator changeout and/or ring replace =ent are as follows:

A. Use silicone'o-rings

3. Use Attach:ent I drying piecedure , ,

C. Tollow Attach =ent II precautions D. Hegger stators for insulation resistance

'1. Ifh200 megeh=s, install stator

2. Ift 200 megohns, contact BW. .

The following.chec%s should be made as a nc.=al r fueling outage maintenance

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'A. Megger stators for insulation resistance ,

' 1. . If y 200'negehns,' stator is considered dry' .

2. .Ift 203 negehns, use Attach =ent II drying procedure'

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K corroded or vet co=nector can cause a wet stator indication... A stator ~

with a low resista:ce reading should have the connector electrically .

isolated fro = .the ytver conduct and the = egger test re-run on ,4 the stator -

, to veri.ty t.he low resistance readin. g. - y .. .

When. s tators are reroved from the CR::M for.o-ring changeout, the stator- .

filler bushings sh:. tis be inspected for evide=ce of corrosion. If any corrosion is found, the filler bushings and end turns. should be lightly

' coated with "Belco Silicose Grease" using a suitable brush'or list-free ' .

. cloth, -

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Th facilitate the' vacuun drying operatica, the stator vent plus can be

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repisced with a ve=t edapter. ,, Diamond Power has these adapters available .

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If.you have'.any"far- her. questions, please do, not hesitate' to contact =e.

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':.' L. C. Bogers Site Operations Manager / Manager, Site Services i . -

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cc: J. D. Phinney J. C' Herbein T. T. Scott,

• R. M. Klingsman J. T. Janis '

L. R. Pletke .

W. H. Spangler .

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bec: D. Culberson (SIP 5/176' ,

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