ML20042G912

LER 87-012-01:on 870408,component Cooling Pump 1A Tripped When Surge Tank Level Dropped to Low Level Pump Trip Setpoint.Caused by Breakdown in Communication.Mod to Component Cooling Sys completed.W/900507 Ltr

ML20042G912
Person / Time
Site:	Byron
Issue date:	05/08/1990
From:	Pleniewicz R, Schrock J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BYRON-90-0420, BYRON-90-420, LER-87-012-02, LER-87-12-2, NUDOCS 9005160274
Download: ML20042G912 (5)

Text

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. , ,e^x Commonwealth Edison  !

s Byron Nucirit St; tion -

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l 4450 North G:rman Church Rold ,

s Byron, Illinois C1010 i

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May 7,-1990-LTRt BYRON 90-0420  ;

Dear Sirs f

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The enclosed Licensee Event Report from Byron Generating Station is being .,

transmitted to you as a Supplemental Report to 87-12; Docket No. 50-454. -'

Since ely, s

l R.' Plenlewicz j! t l Stat.lon Manager ,<

l- Byron Nuclear Power Station ,

I RP/jr i

Enclosure Licensee Event Report No. 87-12 ,

i cci A. Bert Davis, NRC Region III Administrator .

W. Kropp, NRC Senior Resident Inspector INPO-Record Center CECO Distribution List ,

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~k 9005160274 900509 ,

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LICEN$tE EVENT REPORT (LER)

Facility Name (1) Docket Number (2) Pace (3)

Bvron. Unit 1 01 51 01 01 01 41 51 4 01 l of! 0!4  ;

T5tle (4) - gggFgTY RELATED COMPONENT COOLING INOPERABLE DUE TO L0$$ OF WATER INVENTORY CAU$ED Event Date ($1 LER Number (6) Resort Date (7) Other Facilities involved (8)

Honth Day Year Year // $equential Revision Month Day Year Facility Names l Oceket Number (s) 77 ,/j/,/

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// Number /// Number NONE 01 hi 01 01 of l l___

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.,j l 4 018 817 817 01 1 l 2 011 015 018 910 01$l010101 l l  !

THl$ REPORT !$ $UBMITTED pVR$UANT TO THE REQUIPEMENTS OF 10CFR OPERATING d one y more M W _ M oW nd ( W, MODE (9) 6 20.402(b) 20.405(c) _ $0.73(a)(2)(iv) __ 73.71(b)

POWER _., 20.405(a)(1)(1) __ 50.36(ci(1) __ $0.73(a)(2)(v) .__ 73.7)(c)

LEVEL 20.40$(c)(1)(ii) 50.36(c)(2) .2_ 50.73(a)(2)(vil) Other ($pecify (101 0l0 g10 I_

20.405(a)(1)(iii)

_. 50.73(a)(2)(t) __ 50.73(a)(2)(viii)(A) in Abstract

/ / /,/,,/ / / / /,/,/,/,/,/ / //,/,/,/ /,/,/ /,/ / ,_ 20.405(a)(1)(iv) ,,._ 50.73(a)(2)(ii) _ 50.73(a)(2)(viii)(D)* below and in

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//}/}/}////j/}/}/}/}////}/}/}/j/j/}/// _ 20.405(a)(1)(v) _ _ 50.73(a)(2)(ill) .__ 50.73(a)(2)(x) Text)

LICENSEE CONTACT FOR TH15 LER (12)

N;me TELEPHONE NUteER AREA CODE

.1. Schreck. Operatino Enoineer Ext. 2216 8l115 213141-l514141 l; E0MPLETE ONE LINE FOR EAEH COMPON N FAILURE DEStRIBED IN THIS REPCBT (13)

CAU$E $YSTEM COMPONENT MANUFAC- REPORTABLE CAU$C SYSTEM COMPONENT MANUFAC- REPORMBLE TURER TO NPRDS TURER TO NPRDS 1 I I I l l I I i l l l l 1 1 I I I I I i l i l l l l l SUPPLEMENTAL REPORT EXPECTED (14) Expected tlanth l Du l Year Submission

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lyes (If v & iQmplete EXPECKD SUBMIS$10N DATE) X l NO l !l l AB$iRACT (Limit to 1400 spaces, i.e approximately fif teen single-space typewritten lines) (16)

On April 8,1987, at approximately 1725. a contracted maintenance crew began work on the Limitorque motor operator of the "1A" Residual Heat Removal (RH) Heat Exchanger Component Cooling Water Outlet Isolation Valve, ICC9412A. This valve was a point of isolation for work on the RH Heat Exchanger, which required it to be drained of Component Cooling Water (CC). shift Operating personnel granted permission, with the understanding that if it became necessary for the crew to stroke the valve, they would obtain authorization. The maintenance crew stroked the valve in order to release torque on the motor gear set.

it is unclear whether they actually received authorization or not. This allowed Component Cooling Water to back flow through ICC9412A to the Heat Exchanger and out the drain. This caused the (CC) surge tank to reach the low level CC Pump Trip. The "1A" CC Pump tripped at 1726 on April 8, 1987. The surge tank is common to both trains, consequently, both trains of Component Cooling were inoperable. The leak was discovered and isolated. The system was then re-filled, and the "1A" CC Pump re-started. The total time both trains were inoperable was 17 minutes. The cause of the event was a communication breakdown between the maintenance crew and Shift Operating personnel. Contracted maintenance personnel now work under the same procedures as station personnel which requires proper authorization prior to stroking any valves, in addition, a modification has been completed to provide automatic makeup water to the Component Cooling system in the event of a leak. The safety significance was minimal. RCS Temperature never exceeded 85'F.

There was one similar previous occurrence reported in LER 455/86-01.

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(0574R/0065R)

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,. _ _ LI([t(K[_ EVENT REPORT (LER) TEXT CONTINUATION FAttfITY NAME (1)' DOCKET NUPSER (2) LER NupeER (6) Pane (3) i d

Year //j // Revision j ff ' Sequential f

/

/// Number /j/j

// Number avren. Unit 1 0 1 5 1 0 1 0 1 0 l 41 51 4 817 - 01 1 12 - 011 012 0F 014 ll TEXT Energy Industry identification System (E!!$) codes are identified in the text as (xx)

A. PLANT CODEITIONS PRIOR TO EVENTt Byron Unit 1 Event Date/ Time. 04/08/87 / 1725

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MODE 6 - Refueling Rx power 0%... RC$ (AB) Temperature / Pressure 85'r /de-eressurhRd

8. Q[1CRipT10N OF EVENT:

The "1A" Residual Heat Removal (RH)[SP) Heat Exchanger was Out of Service (00$) for gasket repleenment. -

The shell side, consisting of Component Cooling water (CC)[CC) was isolated and drained. . One of the points t of isolation of the 005 for CC was the RH Heat Exchanger CC Outlet Isolation Valve, ICC9412A.

The grease in Limitorque valve motor operators was scheduled to be changed out during the refueling outage. This activity was being handled by contracted maintenance personnel, supervised by utility management. Since this involved numerous Limitorques, the Work $vpervisor developed a plan with Operating j Management that each valve would be only taken Out of Service electrically for personnel protection. If it became necessary to mechanically stroke the valve the maintenance crew foreman would ask the $hift Engineer for specific autherlaation. This plan was consistent with $tation's work practices and programs.

At approximately 0842, on April 6,1987, the Work Supervisor (utility non-licensed) for the RH Heat Exchanger gasket replacement requested a temporary lif t of the mechanical portion of the Out of Service on ICC9412A in order to perform the grease change and gear box flush on the motor operator of ICC9412A. The Operating Shift Foreman (Itcensed) granted permission with the explicit' agreement that work was only to be performed on the motor and that the valve was not to be stroked open for any.reasor..

At approximately 1725, on April 8,1987, the contracted maintenance crew (non-licensed) began work on the valve. During the course of their work it bocas.e necessary to release the torque on the motor gear set which required stroking ICC9412A approximately half open. They stroked the valve. This allowed Component Cooling water to back flow to the RH Heat Exchanger, fill the empty Heat Exchanget, and pass through the open drain valve. The CC surge tank level dropped to the low level CC Pump Trip setpoint. The "1A" CC Pump, which was' running to support plant operations, tripped at 1726. The CC Surge Tank is common to both CC Trains, consequently both trains were inoperable at this time.

Shif t Operations, in response to the "1A" CC Pump Trip and Low Surge Tank level, dispatched an operator to

, investigate. He quickly determined that CC was draining into and out of the RH Heat Exchanger. He then closed "1A" RH Heat Exchanger Component Cooling Outlet throttle valve, ICC9507A, to isolate the leak, i

Water was.then restored to the surge tank and the "1A CC" Pump re-started. The total time both trains of CC were inoperable was 17 minutes. There were no safety system actuations.

l A Generating Station Emergency Plan Alert was declared and appropriate notifications made.

1 This report is required pursuant to 10CFR(a)(2)(vii). I I

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. . LIEENSEE EVENT REPORT (LER) TEXT EONTINLIATION

, FACILITY NAME (1) DOCKET NUPSER (2) LER NLNSER f 6) Pane (3)  ;

Year /

fj/p/ $equential /p/p/ Revision [

/// Number p//

/ Number _

Byron. Unit 1 0 l B l 0 l 0 1 0 1 41 51 4 817 01 1 12 - 011 013 0F 014 l; TEXT Energy Industry Identification System (EIIS) codes are identified in the text as (xx)

C. (AUSE OF EVENT: l The root cause of this event was a communication breakdown between the contracted maintenance crew performing the work and Operating Shift personnel. l The contract maintenance personnel had been instructed to always receive permission from the $hif t Engineet-prior to manipulating the valve they are working on. The maintenance crew was interviewed and insist they did receive verbal permission to stroke ICC9412A. However, they do not remember who they talked to. shift operating personnel maintain that they never gave such permission. There was no requirement to document this permission in writing, Neither version could be corroborated.

i D. SAFETY ANALYSIS: '

Plant and Public safety were not affected. Loss of a heat sink for the Reactor Coolant System (RC$), ,

without loss of circulation, has a negligible effect for the short period of time the Ir/s occurred.

Reactor coolant temperature was maintained at approximately 85 degrees Fahrenheit through-out the event and RC$ forced re-circulation was maintained, via the operating RH train. The water level in the reactor cavity was greater than 23 feet, providing sufficient heat sink during the loss of Component Cooling. It would have provided suf ficient heat sink and cooling for an extended period of time if RH flow had been lost.

E. CQRRLCIIVE AET10NS:

Communications and proper work coordination between station maintenance personnel and Operating Shift personnel has been effective and does not warrant concern, consequently, corrective actions are focused on ,

contracted maintenance personnel.

As interim corrective action, contracted maintenance personnel have been re-informed of the requirement to obtain Shif t Engineer authorization prior to stroking any valve they are working on during the Limitorque motor operator grease enangeout.

The practice of requiring contracted maintenance personnel to get written authorization from the Shift Engineer was effective during startup operations. Contracted maintenance personnel now work under existing <

station procedures which require proper authorization prior to stroking any valves. The Out cf Service l program has been revised to give specific controls for work on a Limitorque valve. For contractor maintenance, an 00$ care will be placed on the valve so that specific authorization to operate the valve will be controlled by the Temporary Lif t Program or a second isolation point will be used so that the position of the valve being worked on does not affect the operation of the associated system.

A modification to the Component Cooling System has been completed to provide automatic makeup water to ,

maintain surge tank level. This would attempt to maintain water inventory in the event of a leak. I 1

This report &as placed in the Licensed Operator required reading program. In addition, this report was distributed to $tation Departments to be disseminated to respective department personnel.

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i0574R/0065R)

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r-LICENSEE EVENT REPORT (LER) TEXT CDWTIMUATION FACILITY NAME (1) DOCKET NUMBER (2) LEn MunnEn (6) Pane (3)

' Year- /// Sequential /// Revision j fff fff

/// Number /// Number l svren. u' nit i o I s I o I o I o I al si 4 sir - of 1 12 - oli 014 .Or 014 ll TEXT Energy Industry Identification System (E!!$) codes are identified in the text as [xx] l 1'

F. PREVIOU$ OCCURRENCES:

i LER NUMBER TITLE i

455-86-001 Both Trains of Component Cooling Inoperable Due to Personnel Error in a Relief Valve Setting.

G. COMPONENT FAILURE DATA: .

l a) $NUFACTURER NDPENCLATURE MDDEL Nut 91R MFG PART NUPBER ,

Not Applicable b) ELSULTS or NPRDS SEARCH!

Not Applicable i

-I i (0574R/0065R).

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