ML20085A467
| ML20085A467 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| 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) | |
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-Babcock &Wilcox
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March 20,1978 I
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f RD4-I-3 e6 3064-II-126 Mr. L. L. Lawyer Manager, Generatier. Cperations i
Metropolitan Liiso: company
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Post Office Box Sh2 *
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Reading, PA 19603 r
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Mr. 'G.
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Station Superintende=t F
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Hetropolitan Ediscs cn=pany
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"Middletown, PA 1TC57 E
Superintendent, Unit I Mr. J. P.. O'Hanlom i '. "
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Post Office Box 480 i:
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Middletown, PA 17067.
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Subject:
CRDM St tor o Ring Replacement
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Operating experience at so=e 3&W plants has shown th..c the ' control ~ rod. * ".,- * ",
5 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.
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E failure.
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
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replaced vith silie==e o-rings during your next refueling outage.. This 4-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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- 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
... items x
'A.
Megger stators for insulation resistance
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- 1.. If y 200'negehns,' stator is considered dry'
- 2..Ift 203 negehns, use Attach =ent II drying procedure' f
K corroded or vet co=nector can cause a wet stator indication... A stator
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with a low resista:ce reading should have the connector electrically isolated fro =.the ytver conduct and the = egger test re-run on the stator
,4 to veri.ty t.he low resistance readin. g.
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When. tators are reroved from the CR::M for.o-ring changeout, the stator-s 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 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
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J. D. Phinney J. C' Herbein T. T. Scott, J. T. Janis R. M. Klingsman L. R. Pletke W. H. Spangler bec:
D. Culberson (SIP 5/176' y.
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