05000327/LER-1980-150-03, /03L-0:on 800927 During Surveillance in Mode 3, Check Valve Leak Rate Exceeded Tech Spec Limit.Caused by Valve 63-635 Stuck in Open Position Due to Interference Between Disc Nut Lockwire Tack Weld & Valve Body

/03L-0:on 800927 During Surveillance in Mode 3, Check Valve Leak Rate Exceeded Tech Spec Limit.Caused by Valve 63-635 Stuck in Open Position Due to Interference Between Disc Nut Lockwire Tack Weld & Valve Body

ML19339A641
Person / Time
Site:	Sequoyah
Issue date:	10/28/1980
From:	Cottle W, Kirk G TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19339A634	List: 05000327/LER-1980-150, Forwards LER 80-150/03L-0 05000327/LER-1980-150-03, /03L-0:on 800927 During Surveillance in Mode 3, Check Valve Leak Rate Exceeded Tech Spec Limit.Caused by Valve 63-635 Stuck in Open Position Due to Interference Between Disc Nut Lockwire Tack Weld & Valve Body
References
LER-80-150-03L, LER-80-150-3L, NUDOCS 8011040453
Download: ML19339A641 (2)

LER-1980-150, /03L-0:on 800927 During Surveillance in Mode 3, Check Valve Leak Rate Exceeded Tech Spec Limit.Caused by Valve 63-635 Stuck in Open Position Due to Interference Between Disc Nut Lockwire Tack Weld & Valve Body

Event date:
Report date:
3271980150R03 - NRC Website

text

.

CONTROL BLOCK: l

- l l

l l

l Ih (PLEASE PRINT OR TYPE ALL REQUIRED lt4 FORMATION) to.lg IT I N l s IN Ip'l il@l O IO I 1010101010 l-1010 l@l4 I i l 11 111 l@l l' l@

i4 it UCENSENUMgER 25 26 LICENSE tvet J0 6 7 ;e. 8 b6 8

8 9 LICENSEE CODE e

sUa$ d\\ Ol 5l O! 01 O l 3 l 2 l 7 @l 0 l9 l2 l7 l8 l0 l@l 110 l 2 l8 18 l0 l@

CON'T to 68 Docut ET Nuv6EM 65 69 EVENT DATE 74 IS FIEPCMT C AT E 80 I,

d EVENT DESCRIPTION AND PROSA8LE CONSEQUENCES h I o i 2 ! I While in Mode 3. durine performance of Surveillance Instruction SI-166.10, check I o I s i i valve 63-635 leakage rate exceeded the 1 GPM limit of Technical Specification 3.4.6.2.f.;

the' #4 cold leg accumulator level fell below the limit of Technical j

Io I4 l lDurine the test l0 Isl l Specification 3.5.1.1.b.

There 'was no effect upon public health or safety. Previous

~

I L, occurrences - none.

o 6 I

10171 1 I

10181 1 so CAust C 3 M P.

vatvt sysitu CAust

• suSCOI:E COM*ONE NT CODE sV8 CODE St; scoot CODE CODE C l E l@ y@ y@ [V l A { L lV lE l Xlg l C lg g

10191 i

3 3

9 10 ii

'2 i3 is 33 20 stoutNTiAL CCCUnaENCE' REPORT Revision LE nf eo EvtNTvEAR R E PORT NO.

.CCDE TYPE N O.

@gg l218 l0 l l_l l1l5l0l y

l0 l 3 l lLl g

y-22 23 24 26 27 28 29 33 35 32 MfTM Houms 22 5 8 iT 0 F

8.

suPP E '

UAN ACTuatm T 8C r A T Cr o PL ANT

$ j @ l Z l h l5C lg l36zl@ l0l0l0l l

lY lg lN \\@

lV l0l8l5l JJ J8 3

37 40 en 42 43 44 47 CAUSE CESCRIPTION AND CORPECTIVE ACTIONS h I i i o i I check valve 63-635 stuck in the ocen oosition due to interference' between the disc i

i i I i i l nut lockwire taek weld and the valve bodv. The interference was corrected and the I i l 21 1 valve was satisf actorily retested. The #4 cold leg accumulator level was restored r

Ii131 l within one hour.

it.*I(

30 s

t i oTHEnsTAtus h bisENE h

s r'AN.'

srowEm

^

ciscovEny cts:miptiCN NA l

l B lgl Failed leak rate test j

liISI W @ l0l0l0l@l 82 M

d5 as 3D A0 rive ry Co'OrtNT mELE ASED 08 n!LE AM AMOUNT of ACTivtTv Lo:ATION CF RELEASE 1

I NA l

i li f o i L.Lj @ Lz_J@l NA

,Ense...,'El t,os " Es otscairTroN h Nuve t n TvrE l

[

l i l il I o l o l o l@l z l@l NA

,taso,,,E L iN,u'n',Es otsCniefioN@

NivcEn l

1oIolOl@l NA i e l

i.

2 LOis or oa DauaCE To FACILify TV'E DEscalPTION l

l li l9 i I z i@l NA D"

3 l

oEscaiPTroN h issut NA

- WG c

3 l

ll ll ll1]llill IIITl hl 6s es 8

s e to Name of Preparer W. T. Cot.tle[ C. B. Kirk Phone 615-842=8261

,2,[ "#

8 011040g

e Tcnn3:cee vc11sy Autnoricy Sequoyah Nuclear Plant LER SUPPLDENTAL INFORMATION SQRO-50-327/80150 Technical Specifications Involved 3.4.6.2 and 3.5.1.1 Reportable Under Technical Specification 6.9.1.13.b Date of Occurrence: 9/27/80 Identification and Description of Occurrence During performance of SI-166.10, safety injection system check valve 63-635 leakage rate exceeded the 1 GPM limit of Technical Specification 3.4.6.2.f.

During the test the #4 accumulator level fell below Technical Specification 3.5.1.1.b limits.

Conditions Prior to Occurrence Unit in Mode 3.

Apparent Cause of Occurrence The excessive leakage of the check valve was due to the valve being stuck open, apparently caused by interference between the disc nut lockwire tack weld and the valve body. The cold leg accumulator is used as a pressure source for leak testing 63-635. The excessive leakage through the valve resulted in decreasing the accumulator level to less than the Technical Specification limit.

I i

Analysis of Occurrence There was no immediate adverse effect since check valve 63-635 14 isolated from reactor coolant loop #4 by check valve 63-563. Check valuc 63-563 had previously been tested satisfactorily.

~

Corrective Action

The check valve was isolated and the #4 accumulator level was restored to within the Technical Specification limits. The unit was cooled to Mode 4 and check valve 63-635 was isolated for maintenance. The valve disc was found to be stuck in the open position due to incerference between the disc nut lockwire tack weld and the valve body. The interference was corrected by relocating the lockwire tack weld. The valve was subsequently retested satisfactorily.

The valve vendo'r is assisting in the evaluation of the apparent interference which caused the valve to stick open.

Failure Data None