ML20084N882

AO 50-249/75-34:on 750807,isolation Condenser High Flow Switches 1349A & B Exhibited Instrument Setpoint Drift.Cause Unknown.Switches Reset

ML20084N882
Person / Time
Site:	Dresden
Issue date:	08/15/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084N886	List: ML20084N882 ML20084N890
References
506-75, NUDOCS 8306090102
Download: ML20084N882 (2)

Text

' - ,

W ^

Q y'Q I m N Common th Ediron /

- - One First National Plaza. Chicago. !!hnois

\/ / Address Reply to: Post Office Box 767

.~ -

.,- Chicago, Illinois 60690 PES Ltr.2 06-75 Dresden Nuclear Powcr Station ~

R. R. El Morris, Illinoic 60450 Aucust 15, 1975 g'.

% Q' i  ?.,

~

I'r. Dr.es G. I~eppler, Recicnal Director _

c.c Directorate of Rc.,,21n tory 0;cretion-Rccien III ..

U.S. Uu?lc9r Recalatory Ccn..ission y ', .

g 799 Rooncvelt EcM ' <. J ' -

Glen Ellyn, Illinoic 60 07

.c.u.n a ~t. .r~., , .p;. . .n~,

n r.o. .e .n -

nr ~n,r. r.37 (.; . b . 3. en w

-.- .rne.

m. ~ rr-um a rac .- - .'"70~Na

er-wTr- --

,.,L.,,c.,c,..,._.,,

2, .m. .. , .

. .. -, . r,.'Ix . ., -e .;

. n. ..3 .,.. n.r.

-_2 0T',.m. -vm. . . .

Rolcrenecc: 1) Rec.tictory Guisle 3.16 Rev.1 Aprendi:: A

2) Ectificatien of Recien III cf U. S. Nuclce Reculatory Co~r:iscien Telephone: 73. F. Johnson, U30 hrs. on Lucust 8, 1975 Telc;-=:  ?:r. J.1:erylcr, U37 h c. on Aucast 8, 1975. '

?) Drawing Euder ::-?59 12E2505 Retort Utraber:

E':-2M-o/~6.,-.1 C 2eport Ontc: 1.u;20t U,1975

,. -(

Cccurrence D".to: 1.ucant 7,1975 acility: Dresden Uuclear Pcuer Stition, I.:orric, Illinois 60h50 ,

r , ,.ny

.. m. m. .r.e.n m. <'a. m. r. ., .

An inrtru ent setmint ri-if t of icolttion cendenner hich flov suitebec 1349A a E occi~ rcd on Urit-3. - .

m . . _ v. m 7. . - . n, om, er, n,, r., ,.r_....

-Unit-3 *: e in. the cold chutdown mode for a refuelinc~ outace.

D7."",3TFTION CP OCCU'F:*302 At n,mproximately 1500 heurn en Aucant 7,1975, during routino steveillence of dif-ferentini r'dtchna U49A !.: P, both m itches ucro found with retroints above the Technical Crocific, tion li;ait of $ 32" H 0. Switch 149A var found at .36" H p-O, and 2

evi t6 1?':9~,at'z3.5"Hho.

D:l'rMAT7CN CP APDFCl? CAUC2 0F 0"CD.'CICE I

No definitive cauce een be cotabliched at thic time. Surveillanecc have not been g

perfot cd on the ncitchen during the outage. 1.'aview of prior surveillancen hno indicJted that tbo cetrointn of thene catches are cubject to' a clow drift.

8306090102 750815 -

PDR ADOCK 05000249 S PDR L h 'd 1 E.

Of

e

,, ./~ %

i,v em P S Y G a -

ca m- ml'[,T s e n,,7 CLv.r. Lrw~ t' m S:: itches 13hoA e E were found uith acceptable setpointa during the routine 11, 1975, cene 36 days before Unit-3 wascct-surveillance co". ducted on D rehIt 4.c considered unlikely thst the evitches' clut do ci for refueli c. ,

points exceeded 'Neh.7 0 cc. li-ite ' tile Analysis the unit of the vanpast operatinc, perfo-nance given of thethe 150-dar cr'n 'cotucon curveillrnees.th?.t cetroint &ift occurs very cradually. The phenoncnon critebec indicate of dercearin7 inctr r ent co woint values after extended cutacec was noted on Enrkrdale pre cice cuitd ec (recert no. 50-2~7/75-17 dated Orch 27,1975).

Enced en the de:~oa-:"ared relia':ility of c *itchen 1349A & B uben cheaked '

rou*inely dri-:- ^reration ,

it 4.0 concluded that this occurrence in no way M 4e.

Cr.'.h. .. 'l, C ."' 4 M

-p""-.', ".c ". awr,,".w. y_1 o". C'.

u n. a n.c."-.O

-a.t.

g C ym. .. ' ,m7 . - . '" T.mr . '

I

""a".d" c'4 A 2v.G, 1 " u. .g O . t t, o .,i n. 2,....n p, . 3 , ,-. .4.> c. 1 _A .

m .n. .e.,a . . .,,r.- . . - , ,.c....

, , .: a ,. .

,.c. . e c t.

-,r,wl e. a w, i. dy..s.u v- p.; t.-u a.

4.

. , 417 .. c t v. ., C.,1 v, . . , q

. .~ m,,m,e ,. 4. .c4wC &v

~

. ...,, 4 .; n.~,,. Aw, -.,..m..,.5.

y_ .

,L. .,. ., .C.- .,r - . . ,

?. .?.T i.im .' " m i.

4 4 , , r a. .~.pn.4. , H ,, U .

. .s u , e,1 1 As,7 . . n, . c. .e.> CA -..v.. .. -.-

,.:.A,_,,.,, 3 c am,.A,,.,,.....,+ .v f.u..v -

c. - w4 o r

%nar, wo- n.,t ,

. _ . . j y

., . . c. -- _r.,,,,..,c, ,. 4 wg

. ,,. m. a 4. . + .4

4. ., 3. . , . ...

.-3a r e. ,]. .n n. e.,

.( , , ,,- u. , - . . , - . . . g . , a .,s ., . ~... . , .

.w.. .

n. y. g.wp. .;... r . . n ,., w,,, ,.4 n m.A g;

~.~.n..

-. a - 1. ,d n.a. ,

e .,  ; 4 n. w

. n. ,- k. m ,

u. . ...-.e....a . . . ~ .. -. -

f.,..~, a La. .; cm. ,u ,c_

p j

4. , nn, . .. .- n. 31,C r. ., t. C,,. . .

. +

..i. ., s ,~. : , + 2 ,, v. n , s. . . . , . ..

. n,.,,.,.-r...,n.

. .. . . . . ~ . .- ,

- ^ ' # ^*w*., " . , " . ' . . " . ~ ~ . ' r' . 1.0,""F. 0.

c. C ". C '.'.#.

. *-1... -'..".""'.'_"n, ..'#^'.'. - :. v a .. . m

~

Y l

\

g j .Superintenuent

'. .,tephcncon

~~

m_ .v- . .. . . i. ' . ,4. , C .r, I

I I

l l

J