ML20084Q644

Comments on Util 700403 Submittal Re Disposition of safe- Ends

ML20084Q644
Person / Time
Site:	Nine Mile Point
Issue date:	04/07/1970
From:	Staehle R OHIO STATE UNIV., COLUMBUS, OH
To:	Collins W US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084P985	List: ML20084Q227 ML20084Q318 ML20084Q633 ML20084Q644 ML20084Q655 ML20084Q663 ML20084Q676 ML20084Q686 ML20084Q738 ML20084Q901 ML20084Q905
References
NUDOCS 8306130518
Download: ML20084Q644 (2)

Text

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• * * ' O S TAT E U N IVE R S Ih III F A . (ENT OF METALLUR CIC AL 6 NOINEI11NG 816 W E B Y 19T18 A VEN U E cot.uunus, ouro 0 21o

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E 7 April,1970 ..

Mr. W. J. Collins Technical Stpport Branch Divisica of Ccaplicnce U. S. Atcraic Encrgy Cca.r.insica .

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7920 Norfold Aven.wa .

Ecthesda, foryland -

Dear Joe,

You rogmated my infonal review of the 3 April,1970 doct=cnt submi.tted to Dr. Pctor Ferris fran M.11. Pratt of Niagara Mudc Power Ccupany ccacerning the despecitica of sensiti::cd safe ends.

I have tha follcaing specific ccamr.ts:

1. The statcirent en page 1 that ". . . cracks . . . arc related to ..

high stress . . . accelerated by . . . possibility of fluorido" seems to re not to 1;c stating tnc cbvicus ccnclusica. Tac crading I

stiu.LLy hua the insica surrace of tac NES safe end secta to bc -

clearly a case of stress corrcsica cracking. There is no evidence of substantial and purely "mcchanical" failure cither of the creep rupture or fatigua type.

Stress corrosion cracking dccs not necessarily require any specific " contaminant" --even c:e/gca. Nor docs sec need to bc specifically transgranular. -

2.

On page 4 under item 3.1.2 (socccd paragraph) there is the point:

". . . transgri:nular cracking which is cbviously chemically induced, rather than ncchanically induced." I find that this is a ccafusing ..

statencnt sinco this is sinply a different type of stress corresica cracking. Both the intergranular anc transgranular cracks are T

.jenanically induced in ccncert with'sc re environment.

The interrelaticaship cccng stress, heavy sensitizatica, and "

cnvironnent is discussed in af :rport of 7 April,1970. In the case -

of the insido intergranular cracks it seem that the primary causative .

olcarnts are cqually: heavy sensitizaticn, stress, and om/ gen concentration.

If g one of those is =cro then cracking will not occur. It is therefore not clear whero to place the bla:m.

I 8306130518 700520 m PDR ADOCK 05000220 k p PDR ..

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Tno suggesticn that fluorido ray be can';ativo (pago 1) ray b3 questiawble in vie.1 of the fact that race;cra :'ch::ak water chc.T.intry dcen not chcx/ fluoride in their nonral cnalynin (this i rray bo conjectcd but r.T/ ingrenaica in that tne :N , tater cc.mistry chcwcd r.o detecLible fluorido ca a routine basis) . I:cuevcr, in thin non-floaing regica it is not pcanible to be cpccific in this area cnd any ccaclusica nuy be ccajectural.

I hopo the abova will bc unoful.

Lost ro.jarus, Since "ly, i

- R. W. Stachle Associate Professor KG:jgk l

l cc: R. Lofy

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