ML20085C924

Ro:On 741011,control Rod Drive N-11 Jammed Fully Inserted Past Position 00 & Would Not Withdraw After Increasing Drive Pressure.Caused by Broken Seals on Stop Piston.Drive N-11 Replaced

ML20085C924
Person / Time
Site:	Quad Cities
Issue date:	11/15/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 8307130218
Download: ML20085C924 (3)

Text

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1. 1. C:an..Jnw:: lth Edis:n

/ ' C '3 OJad-Cit'03 Concrat;ng Stat:Cn

--'3 Post Off ce Box 216 i * .9 Cordova. l'hnois 61242 M' Telephone 309/654-2241 ea#  %

NJK-74-382 ,

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November 15, 1974 \'.' ~\ , ..

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. i. . ' . . :,8 Mr. Jchn F. O' Leary, Director Directorate of Licensing Regulation U. S. ATCPIC L' ERGY CCT.::ISS10N Nashington, D. C. 20545

REFERENCE:

QUAD-CITIES NUCLEAR PO'.G.R STATICH Docket No. 50-254, DPR-29 Appendix A, Section 6.6.B.2.b.

Dcar Mr. O' Leary:

Enclosed please find the following Unusual Event Report for Quad-Cities Nuclear Power Statien.

This report is submittcd to you in accordance with the rcquirements of Technical Specification 6.6.B.2.

Verf truly yours, CCMP.0'; WEALTH LDISCN CCF.PANY QUAD-CITIES EUCLEAR POWR STATICU

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!!. J. Kalivianakis /

Station Superint<ndent NJK:GS/dp cc: Region III, Directorate of Regulatory Operations J. S. Abel 8307130218 741115 g4ono

.t I,v 0 v PDR ADOCK 05000254 PDR s

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COPY SENT P2GION - ,

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g,P0lif Pl.TE: 11-11-74 DEV3 AT10N M'PR: 10-11--76 IDNiTT FT"ATIC:: OP tt:?)y T 1.VF '.T:

Control red drive 11-11 jarmed fully incerted past position 00. The rod did not. withdraw cycn with an increascd drive preccurc of 400 paig.

C_OFDITTO:!S PRTOR TO U': USUAL FVE:,T:

On Octobcr 11,1974, Unit 1 was returning frcm an cutat;e follouing an ex-plo0 ion in the off gas syst,en. At 1920 hrs. the reactor operator began pulling rods to critical nnd at 2051 hra. the rcactor was critical. The probl<a uith rcd I;-ll was diacovcred before the reactor was critic 9.1 );h51c the operator was pulling reda in group 3, array 3, sequcnce B-1.

DF.SCRTPTTON 0:' U'"JSHAL F7EMT:

,In sequence B-1, group 3 calls for uithdrawal of nrray 3 from 00 t'o 06 as part of the black cnd white red pattcrn. The fourth red in array 3 is red 11-11.

At the time the operater tricd to withdrre red I:-ll to pocitien 06, the red was not latchtd at 03 but driven Tast the 00 positicn na 3rdicated by the crecn background licht en the digital pocit.icn ir.dicatoro. The operator was urable to withdrew the rod with norml drive prccoure and una ctill unable to withdraw the red after increacing the drive prcscure to approxi-ratoly 40J poig. An cquipment operator wac then scnt to the control rod drive r:cdule end by having hin vcnt the drive to cpply full drive preccurc to the red, the centrol rcc a operater van able to latch the rod at pociticn

00. Upen cubacqucnt uithdrm.nl of the red, it pas discovercd that with abcut 250 pig drive pr(caurc the red moved cxceedingly fast,. It travehd on the order of tuo not chca (24 notchca pcr red) (ach accend. A work rc-quest was writtcn to chcch the centrol red drive.

DFSIC::' TICE 07 APPL.?"'!T_ Cf.USS 07 l':USMjJL EVFq:

IRc. oval and inspect, ion of the control red drive shoucd the drive to have broken seals on t,he etcp picten. 1:othing else was found to be abnornal with the drive.

A!!ALYSIS OF _UNUSitiL kVM.T:

At no time was there any danger to the cafcty of the plant, plant personnel or public. Continued ucar of the stcp picton seal would eventually have resulted in the inability to withdraw red li-ll, failure in a safe conditicn.

The capability of the red to adc.quatcly perform its scra:a function was not impaired.

CORRECTIVE ACTIO:1:

Control roll drive !!-11 was recoved and replaccd on 10-16-74. 'Ihc ncw cen-trol red drive una tir.cd and tcat.cd satisfactorily. The defcetive drive was taken apart, and ir.apc et.(d and fcund to have brchen stop piston scals.

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FA]LUPE DATA: .

I This ia the first, time a prcblcct like this h to occurrcd on red f!-ll.

Florn stop piston se..10 have be cn expericnccd beforc, but neycr with the problw. of a rod being stuck in Fact 00. llorn stop p3ston scals are usually associatcd with drifti.v reds follwing a scram (ref. D-4-1-74-69 and D-12-2 '/4-42) .

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