ML20084R806

Ro:On 741127,during Valve Operability Check,Core Spray Valve MO-3-1402-24A Failed to Open.Caused by Cracked Contact Base Plates Allowing Contacts to Become Misaligned & Preventing Proper Valve Operation.Valve Manually Opened

ML20084R806
Person / Time
Site:	Dresden
Issue date:	12/17/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
900-74, NUDOCS 8306150590
Download: ML20084R806 (2)

Text

..

~ 2

[

3..,s C:mrp, wealth Edicon

1. [

One FirA._,jn,henal Plata. Chicago. litmois j

. i < U/g Address Reply to Po;t Off:ce Box 767

~

Yg/ Chicago likno;s 60090 i '

4 BBS I,tr #900-74 Dresden Nuclear Power Station R. R. #1

- "rC' %

Morris, Illinois 60450 3

S.k December 17, 1974

/

N '\\

,,?

b

%.b D

k g('$D8 h

Mr. James G. Keppler, Regional Directoa p

Directorate of Regulatory of Operatiens-Region III

\\

%!"~,,.t.

"'g-j;,

1. f U. S. Atomic Energy Co=11ssion

\\

L.

799 Roccovelt Road

\\kg[/

Glen Ellyn, Illinois 60137

SUBJECT:

REP 03T 0? K'J3Uf1 EVF2*P PER SECTIO:7 6.6.C OF THE TECIDIIC/1 SPECJFICATICIS DESD:3 U'!1T % AEC DOCEET 50-249

References:

1) Regulatory Guide 1.16 Rev. 1 Appendix A

2) Droeden Station Drawing M-358

3) Dreedon Elcetrical Print 12E3431 Report Date: December 17, 1974 I

Occurrence Date: November 27, 1974 Facility: Dresden Nuclear Power Station, Unit 3,1'. orris, Illinois i

IDEI7PIPICATIO'I 0F CCCURRD:CE Core Spray valve I'0-}-1402-24A failed to open during valve operability chcck.

CONDITIONS PRIOR TO OCCURREtCE Prior to the failure of core spray valvo MO-3-1402-24A to open the unit was in the start-up mode and recovering from a scram which occurred earlier that day. At the time of the failure, start-up checks were in progress.

DESCRIPTIO.I OF OCCU?3Z:CE Cn November 27, 1974 at about 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> a valve operability check was being perfomed prior to unit start-up. Mcma31y open valve EO-3-1402-24A wan' cycle'l to the closed position. Upon closing, valvo position indicaticns were lost. Attempts to re-open the valve c1cetrically were unsuccccafttl.

4 7

e3gi h0 N h

j o

8 12 %

COPY SDrr RFX; TON

r Mr. Jancs G. Ecppler Deccaber 17, 1974 IESIC?1TIO:: OP tr?/Jiz. 3 C"5SE OF CCCU3RE':CE Upon invectir ation it no detemined that the cere:a on !!ovember 27, 1974 nac due to a uater Lez.ner in the core cpray cycte:a which inadvertantly actuated the ?hin Steam Line Flow critchec.

Durinr; the water ht=cr the limit critches for the ~-1h02-24A valvec voro dr.a.;cd.

On inspection of j

the limit cwitches it was found that the contact tacc plates ucro cracked which allowed to contacts to becomo micaligncd, and preventinl; proper valve operation.

/d!ALYSIS CP OCCU'IE:CE t

During the failure of the Core Spray valve >1402-24A the cafety of the plant and public uas not in jeopardy. The F1402-2hA valvc was manually opcned to maintain core spray cyctcm operability until repairc were completed.

In addition, all other cafety systcmc ucre operational at the time of tho failure.

CORRECTIVE I.CTIO'!

The in:nediate correctivo action taken was to r.anually open the 3-1402-24A valvo until repe.irc ucre completed. A modification has been initiated to relocate the Main Steaa Line Flow cwitches to an arca were they would not be affected by core cpray operation.

In addition, all the limit switches associated with core spray actur operated valvec ucro incpoeted and no additional enemaliec ucre noted.

(

FAILURI: DATA The lact reported failure of a core spray 24 valvo occurred on February 5, 1971 in accociation with the 2-1402-243 en Unit tuo.

Sinccrely,

$q7f'7,.:

~

a 9,.4..<,

3 v.

'B. B. Stephencen Superintendent DILS:TEL: cup Pile //tEC O

O

.