ML20071G101

LER#78-037/03L-0 on 781116:during Refueling,All Limitorque Valves Were Inspec for Proper Staking of the Lock Nut on the Motor operator.30 of 65 Valves Exhibited Unstaked Lock Nuts.Lock Nuts Were Staked IAW Manufacturer'S Instructions

ML20071G101
Person / Time
Site:	Fort Calhoun
Issue date:	12/05/1978
From:	Andrews R, David Jones OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20071G079	List: ML20071G074 ML20071G101
References
LER-78-037-03L, LER-78-37-3L, NUDOCS 7812200272
Download: ML20071G101 (9)

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EVENT CESCRIPTICN AND PRC8ABLE CONSEOUENCES h j o i : ! l Ouring the 1978 refueling all Li=iterque valves were inspected for preper staking er the!

lo a t I ock l nut on this design no cr operator. The inspection of the notor operaters revealed (

, o 3 ,, , lthat 30 operators vere not staked in accordance with the =anufacturers recc==endatiens.__J

,o33, i Inspection.vas conducted as a result of ecc:=unication with Cenbustion Engineering who j

,g,,, gi nfo::ed 0FFD that. Arkansas (ANO-2) had found several operators unstaked. In an unstaked ;

Iot7i i condition the lock nut could backout due to vibration and cause the ste= nut to =ove i

ar4M'v and disengage the splines resulting in the loss of drive to the valve ste=. [

7 8 9 'J SYSTEM CAUSE CAUSE COMP. VALVE CCOE CODE SUSC00E COMPCNENT CODE SUSCOCE susC0ct l0ist~ lZ IZ l@

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,,, SECUENTIAL OCCURRENCE REPORT R EV'53CN LEn EVENTvtAR REPORT NC. COCE TYPE No.

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,_21 22 23 24 26 27 28 ;3 30 31 32 ACTION . PUTU R E, EP8ECT $wutcowN ATTACHwENT Nesto 4 PRIME COMe, OOupcNgNT TAKEN ACTION ON PLANT METHCO hours a $USMITTED PORMbu8. SUPPU ER MANUPACTURER I22 31@l24 Zl@ lasZ l@ IZl@ 10 10 10 10 I I Yl@ lNI@ IAl@ l L l 210 l0 i(

s si ao 4i 42 42 da 47 CAUSE DESCRIPTION AND CORRECTIVE ACTICNS h i I a ! JThe valve operators supelled by Li=itercue were never staked to trevent the backine cu* I

,, ei; tef the lock nut. The corrective acticn taken was to examine eve-t Limitercue eterster, I

,, ,;. l tighten and stake the lock nut in accordance .rith the nanufacturers instructions. Thir yt

! p, g lcf a total of 65 valves inspected avw4bited this proble= (listed in Attac k

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, ,,, ; valve failures attributable to this proble= have occur ed at Fe

t Calhoun Station.

? I 3 30 y uETwCO CP sACTU's ITATu  % PCwER CTHER STATUS OtSCCVERY CISCOVERY CESCRIPTTON =*.

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@ l0l010l@l13 12 11 NA 44 l l45 Dl @46lInsueetion after notification fre nsss30l ACTiv!TY CONTENT 4ELEASED CP MEL2ASE AMCUNT CP AC*1VITY LOCATicN CP RELEASE NA l l NA i li 8 41 7 4 9 I Z l @ LEJ@l to it 44 46 dC PER$CNNEL EXPCSURES NUMSER Wof OESCRIPTICN *

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1: IofINl@oEsCRiPTtoN\.E l NA /f, b i !Iff II'II I f f I*

, , , . p a .. u, D. Jcnes/3. Andrevs h02d2 M 011 NAME O' k AE* ARER PkCNE: {

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LIR 78-037 O=aha Public Power Distrie:

Port Calhoun Statien Unit No. 1 Docket No. 05000265 A::ach=ent No. 1 Valves Feferenced in Section 27

1. ECV-311 EPSI Loop Isolation Valve

2. ECV-312 EPSI Loop Isolation Valve 3 ECV-31h EPSI Loop Isolation Valve

k. ECV-315 EPSI Loop Isolation valve 5 ECV-317 HPSI Loop Isolation Valve

6. ECV-318 EPSI Loop Isolation Valve 7 ECV-320 EPSI Loop Isolation Valve S. ECV-321 EPSI Loop Isolation Valve 9 ECV-327 LPSI Loop Isolation Valve g 10. ECV-329 LPSI Loop Isolation Valve

11. ECV-331 LPSI Locp Isolation Valve

12. ECV-333 LPSI Loop Isolation valve

13. ECV-3kT SI Shutdown Cooling Valve 1h. ECV-3h8 SI snutdown Cooling valve

15. ECV-291h SI Tank Isolation valve

16. ECV-2934 SI Tank Isolatica Valve 17 ECV-2954 SI Tank Isolation Valve

18. ECV-297h SI Tank Isolation Valve 19 ECV-150 PORY Isolation Valve

20. ECV-151 PORY Isolation Valve

21. LCV-218-2 CVCS VCT

22. LCV-218-3 CVCS SIR W

23. ECV-258 herg 6ncy 3cratirn Valve 2h. ECV-265 E=ergency Boration valve 25 ECV-268 Energency Scration Valve

26. ECV-308 Charging to Safety Injection 27 ECV-138k Aux. Feedvater Valve

28. ECV-10h2C Main Stea= Control Valve 3ypass 29 MOV-S1 Motor operated Drain valve on Main Stea=

30. 307-973 ?rb. hth Stage Ert.

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IJ.R 78-037 O=aha Public Power District Fort Calhoun Station Unit No. 1 Docket No. 05000285 Attach =ent No. 2 Safety Analysis The problem of non-staked or i= properly staked Li=itorque valve operators was identified to the Fort Calhoun Stction by the NSSS Vendor Combustion Engineering. Combustion Engineering informed OPPD that if an operator had an i= properly staked lock nut, the operator stem nut could back out and loss of valve operation could occur. During the scheduled refueling outage all Limitorque valve operators were inspected and 30 operators were found not to be staked. The immediate corrective action was to insure the lock nut was tight and the nut was staked in accordance with the manufacturers recommenda-tions for staking.

The conditions found at the Fort Calhoun Station vere that the lock nuts on several valves were slightly icose, but in no instances was the ste= nut tacked out which would have jeopardiced the operation of the valve. Should an operator as identified on Attachment 1 have failed, the safety of the plant vould not have been affected since redundant systems are available and each failure would have to be an isolated event.

Periodic surveillance testing and/or operation of these valves has proven the valves to be operable. Reference Ccmbustion Engineering letter attached for further detailed information.

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. . _ . . . . - . . , . .es. c m oo:p wa:

Comoustion Engineenng. Inc. , Tcsex: 99297 1000 Prosoect Hill Acac Winescr. Connecocus o6c9s N POWER

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July 28, 1978 CE-18074-436 Mr. T.E. Show: Omaha Public Power District Omaha Public Power District Unit #1 .: Fort Calhoun Station Jon;s Street Station Engineering Services Agreement 4th. & Jones Street C-E Contract 2177 Omaha, Nebraska 68102

Subject:

Improperly Staked Motor Valve Operators

Enclosures:

(1) Section Sketch of Valve Drive Elements (Limitorque Operations)

(2) C-E Supplied Motor Operated Valves

. car Mr. Short: ~

This is to infor1n you of a problem with imoroperly staked or non-staked Limitorque operators on motor operated valves. This problem could cause tha operator stem nut to back out, resulting in a loss of valve operator -

action. It occurred at one plant and subsequently was brought to the attention of ANO-2 (Arkansas) where the Limitort.e operators were inspected and several were found to lack staking.

During normal operation, the Limitorque operator opens or closes valves by rotation of the valve stem within the operator stem nut (see Enclosure 1).

Tha internal portion of the stem nut is made to match the valve stem. The extcrnal portion has axial splines and matches the Li'r.itorque drive sleeve.

To ktep the " stem nut" captured, a locking nut. is screwed into the drive sleeve.

This locking nut requires staking or crimping to keep it from backing off.

the lacking nut has been imorecerly staked, it can back out, which in turn would allow :ne stem nut to move axially and to become disengaged from the splines. A loss of drive to the valve stem results. No torque is applied to tha locking nut during operation; however, it appears that vibration could loostn an unstaked locking nut., -

l It is recommended that you inspect the Limitorque motor ocerated valves at l Fort Calhoun as defined in Enclosure (2). The operators shou'd be inspected for unstaked locking nuts and the nuts staked as necessary.

Very truly yours, ,

AGS:SB:jm < - N Encl. w/l cy. A.G. Schoencrunn

, c:: R. Andrews, OPPO, (1); w/l cy. Manager Engineering. Services X. Morris, OPPO, (1); w/l cy. For: Calhoun-1 R. Chatfield, OPPD, (1); w/l cy.

W.C. Novick, CEXO R. Erlacher, CEXC L. Kesselman, CE-Windsor l S.A. Dunn, CE-135 A. Stathoplos , CE-Windsor l

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- C-E Supplied Motor Operated Valves .

Fort Calhoun -

Valve Tao No. Descriction Vender

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HCV-348 12" - 1500# Gate Velan HCV-347 10" '- 1500f Gate Velan HCV-2914, 2934, 2954, 2974 12" - 300# Gate Darling HCV-327, 329, 331, 333 ,,

6" - 200f Globe Calmer HCV-311, 312, 314, 315, 317~,

318, 320, 321 2" - 1500f Globe Velan o HCV-268 .3" - 1504 Gate Velan o LCV-218-2 4" - 150# Gate Velan E

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C E Power Systems

.' Ocmousuon Engineenng. inc.

Tcl 2C31688-1911 Teler. 99297 ,

1000 Prosoec: MdlAcac Winosor Connecucut 06095 r":s POWER ~

M SYSTEMS July 21,1978 NFS-OPPD-78-40

• Mr. T. I. Shor.

Omaha Public Power District Jones Street Station -

4th & Jones Street Omaha, Nebraska 68102 ,

Subject:

Improperly Stakad Motor Valve Operators Inclosure: (:.A) C-E Letter CZ-18074-436, dated July 23, 1978 Subject - Improperly Stakad Motor Valve Operators (1) Section Skatch of 7alve Drive Elements (t4d e nqua Operators)

(2) C-E Supplied Motor Operated valves

Dear Mr. Short:

Enclosure IA through 2 are provided for your information conear4 g improperly staked or non-staked 1%4 tuque operators on motor oper-ated valves.

Should you have any questions please do not hesitata a contact me.

Very t=uly yours, STION ENG P NG, DC.

A. A L

L. F. Kasselman -

Nuclear Service Site Manager L7K:fd ,

j Enc.

l ec: 1. Andrews, CPPD e W #

I. Morris, 0??D

2. Chatfield, 0??D

• J. C. :u' rrick, CIIC R. Irlacher, 3 S. A. Dunn, CZ-135 I A. Stathopics, CI Tindsor A. Schoenbru=n, CI 'Jindso

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STEM NUT REPLACEMENT & LOCO.NC- INSTRJCTIONS .

1.-5007 CML STAR.ES FR:CR TO LCCKNUT .tMCVAL.

2. REMOVE LCCKNUT(J) TRCf.1 CRIVZ SLZ!v!(1) AT CPEN:NG CF HCUSING CCVCR t. SFECIAL WRENCH SUCH tS SHC'.".'N EELOW -

vn.L FAC:LITt.TE REMCve.L EUT IS NOT REC (SED FCd SA?tE, REMOVE Ct.O STC A NUT (2).

1-CRCP NEW STD.I NUT (2)INTO CRivE SLEEVE U)THRU SFL!NES.

TAP NUT SUGHTLY TO MA:tE SURE IT is SCTTC;.:ED IN THE CRivE SLEIVE.

4.-SCREW IN LCCKNUTC)UNTit TWE TC9 IS FLUSH (Ac2ACx.) WITH TCP OF CRIVE SLEEVCf11AND TICHTEN WITH WRENCd.

1-THEN 5 AKE LCCkNUT IN PLACE AT TWO PCINTS,If.C* APART.

USJNG STAKING TCCL AS SHOWN.

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