ML20084D660

Ao:On 701204,MSIVs 1D,2A,2B & 2C Failed to Close During Biweekly Surveillance Testing.Caused by Out of Step Recorder Indexing Mechanism.Recorder Repaired.Thin Film Found on Pilot Valves.Valves Cleaned

ML20084D660
Person / Time
Site:	Dresden
Issue date:	12/11/1970
From:	Hoyt H COMMONWEALTH EDISON CO.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084D663	List: ML20084D660 ML20084D683
References
04863, 4863, NUDOCS 8304120167
Download: ML20084D660 (2)

Text

(

y

- ~%,N~

e So- as7 i

Y .e 4

~

!y .) / - -

N l

\ b '

/

L,ommonwealth E,dison C,om pany i x Ky '  ;

72 WEST ADAMS STREET

• CHICAGO. ILLINOIS '

1 Address toply to: l POST OFFICE GOX 747

• C H IC A G O. ILLINOIS 40490 l l

Dresdeu !!uclear Power Station R. R. 41 Morris, IlLincis 00450 December 11, 1070

')r. % e: er A. ' 'o : -i s , 91rm tor Di . i.s io : of Pont tor I ice m l '

N.S. Atomic E cr;. Co :niss iou

' la s ' t i: g t o 1, ,.C.

2D545 SUP ' EC "- T. ICE"SE DDR '1, DP ':S et. ' "CI EA'1 O .E:t STATTO'? UNIT 2, SECTIO" -

' , . 'l O 7 THr N 'T.I1 AL S')EC T C "'ATTO'N D ar Dr  ?:orrir:

Ta ic is te res:w

• oi aitot :a! oc c a ranc e i n v':ich fou r main e t orca ' i. m i eol a t io : ca ' ' s '9, 2A, 2b aM 2C alled to n'oro during L l ** '.' i t 'P ei' I ' M. ; c e [ ' ' a , cTCing as r(* rpt ire I a sectioil b.e.D.l.C C[

L.e T, hai.cc' herificatio's an! t h- r. W emcr.Lar ~. ?-<.iocare testing co;aituent i :it ia- as a "esn't o f ea r ~ ie; '!SIV p roal cais ,

r ol . er r , 1. ' / rc g tloa ni ' correerice y tr -

The z it. e ek ! .:rv e il l a:'c e test o.: L-e na ta s t r.an; 11 :e isolatica calves was pe > o rne.' oa lece.6er 4, 1. '

, not ee:' 1 a.n. aud ? a.m. l Suring the t e.c t , maia stean, isolation va:,ee ID, 2A, 2B and 2C ialled to clore using t:e manua: operatit.g switeb al tnough t..e partial closure ope ra t ioa usind LLe test push b;ttoa var tornal cn a'l ';alves.

I'he conditica o the ma it, stecn isolatica valves as found woul1 r

ave i'reveat ed a a to.aa t ic c ! osure of t he a'so'zo noi e.1 valves al though automat ic

< ! ase:v woul d have oc,.' red o! oae ca've la eaa line if an icolatica g[l '

eigi.a l 'tw! b"eu i n i t ia t ed . T' e pres ioar fe ! clorure ter,t uas conducted  ;

satirfactoti; o r. ?iove' t e r 2", 1970. I 2(( Valve 2A operated nornali; af ter exercising with the operating switch. Valves ID, 2d aad 2C could not be closed properly until af ter g severa! oper ations with the operating evitch during subsequent s;. sten oo;dowa. The unit was operating at 299 Mie (962 MWt) at the time of the test.

Add it ioa a l timing tests were co:vlueted on the operable valves which shove.1 that the vatve closure Lines oa va!ves !A and 20 were 5.7 to 5.3 sceoads which e: cceds t he 5.0 second ma -iinua c losure tiine of see-tion 't . 7. D . I of the Technica! Specificatioas.

• 8304120167 701211_ 1 1g gD0486*7-PDR ADOCK 05000237 S PDR i v v. 8 xal REGION

/'[ [ g >

is

. . . *=

, Dr. Peter A. Morris Page 2 Decenher i!, l ') /0 l The high temp 2ratures of the inboard pilot valves of 150 to l 200"? observed at the time of the MSIV failures to close were found to l be erroacous and due to the recorder .lodeving mechanism bein,; out-of-

! sten. Previous data showed the inboard temperatures to be less than i 150 F. The recorder has been repaired.

! j l As required i,y the Technical Specifications section 1.7.D.3, i

an orderly shutdowa vas f aitiated at 2:04 a.m. on December 4, 1 " 70. '

The reactor was suberitical at 7:44 a.m. and in "c ol d s h ut do'ia" a t  !

1 2:05 p.m.

l 1

The subsequent irvestigation revealed a thin film ou de pilot valves whieb is coasidered to have cause<! tSe failure. Ati the pilot

valves were t horoughl;> cleane l and the air supal; lines ni accumulators j . sere blown dova to remove aay particulate r

aterial in Lne .vsteu. Hov-

) evet, ao sip ificaat particulate r aterial was found. Aa inves t iga t ion is j in progress te consider the installation of additioaal filters which veuld serve t o r m...ove ~ a c , particul ate contamination f rom the air suppl to

{ the svo_em.

I I Foll owing the repair work, the main sream isolat ica val ves were j ejcled aad timed in t he cold c ond it ion . ?uactional checks were performed la the cobl conJiLion and following startup at 300 psig operatiag pressure, and at approxima tel y 400 M'.ie. In additica to the normal blueekl' sur-veillance checks a proce !ure has been establinhed to c"cl e the pilot a'ves ou the "A" and "B" main steam lines ar add it iona ! aunber of cines it, crder to evaluate ar eect o '- increasel pil ot valve e crcis ing.

l l A review o' t!.c s itaatica has beca i, ale rfthe xation Uc.iew j 30ard. The S:!d co.:c urred that t'io Technica? Spee l f ic a t io. . r e qu ir e'aca t s vere not aad that the cor rective ac t ica 4as appropriate.

l 1

\. J. -

i.

p * -v /h/ ( g.,

!!. K. ilof t Superin t e:.d e it a

! hGbL3B:dme l

1 i

l l

\

\

l l

I i

.I I *-

A

'