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)

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L,ommonwealth E,dison C,om pany i

x 72 WEST ADAMS STREET

• CHICAGO.

ILLINOIS 1

Address toply to:

POST OFFICE GOX 747

• C H IC A G O.

ILLINOIS 40490 l

l Dresdeu !!uclear Power Station R.

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41 Morris, IlLincis 00450 December 11, 1070

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T. ICE"SE DDR

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O.E:t STATTO'? UNIT 2, SECTIO"

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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 sectioil b.e.D.l.C C[

a 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

' correerice y tr -

ni 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 g[l

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

8304120167 701211_

Specificatioas.

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g PDR ADOCK 05000237 S

PDR i

v v. 8 xal REGION

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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.

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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.

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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-

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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

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the svo_em.

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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.

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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.

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