ML20202F686

Engine Sys,Inc Part 21 (10CFR21-0078) Rept Re Degradation of Synchrostat Model ESSB-4AT Speed Switches Resulting in Heat Related Damage to Power Supply Card Components.Caused by Incorrect Sized Resistor.Notification Sent to Customers

ML20202F686
Person / Time
Site:	Hope Creek
Issue date:	01/26/1999
From:	Galeazzi D, Mason J External (Affiliation Not Assigned)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-99 NUDOCS 9902040139
Download: ML20202F686 (8)

Text

_.

1 ENGINE SYSTEMS,INC.

[_

- . 301, South Church St., Suite 100 / P.O. Box 1928 / Rocky Mount, NC 27802-1928 / Telephone: (919) 977-2720 / Fax (919) 446-3830 January 26,1999 U.S. Nuclear Regulator Commission Document Control Desk Mail Stop 0-11 A1 Washington, DC 20555

Subject:

10CFR21 Reporting of Defects and Non-Compliance -

Engine Systems, Inc. Report No.10CFR21-0078 Synchrostart model ESSB-4AT speed switch (p/n SA-2110)

I

Dear Sir:

The enclosed report addresses a reportable defect and the corrective action to be taken by users of the subject speed switch. This notification is being sent to all of our nuclear customers.

Should you have any questions, please feel free to call.

Please sign below, acknowledging receipt of this report, and return a copy to the attention of Engineering Document Control at the address below (or, fax to number 919/446-1134) within l 10 working days after receipt.

Yours very truly, I ENGINE SYSTEMS, INC.

O Q.d& '

Jo-Ann Mason Engineering Document Control Please let us know if ANY of your mailing information changes - name of recipient,

]6I7 name of company / facility, address, etc. Mark the changes on this acknowf.edgment form and send to us by mail or FAX to the number above.

RECEIVED:

(91)

DATE:

9902040139 990126' 9~

PDR S ADOCK0500035k( PDR Quality Performance With Pride

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LE I i ENGINE SYSTEMS,INC.  ! d;;d )

301 South Church St., Suite 100 / P.o. Box 1928 / Rocky Mount, NC 27802-1928 / Telephone: (919) 977-2720 / Fax (919) 446-3830 )

l Report No.10CFR21-0078 l Rev. 0: January 25,1999 l l

l i

10CFR21 REPORTING OF DEFECTS AND NON-COMPLIANCE COMPONENT: Synchrostart ESSB-4AT speed switch SYSTEM: Staridby EMD diesel generator control systems CONCLUSION: Defect is reportable in accordance with 10CFR21.

i PREPARED BY:

• DATE: 'NMW Donald D. Galeazzi Engineering Manager REVIEWED BY: Ndah hh DATE: x\w\e Michael Nubing Quality Assurance Manager Quality Performance With Pride

REPORT NO.10CFR21-0078 REVISION 0: 1/25/99 PAGE: 1OF3

SUMMARY

Engine Systems Inc. has received notification that Hope Creek generating station experienced the degradation of three Synchrostat model ESSB-4AT speed switches. As reported in Operating Expenence document OE9504 (see Exhibit 1), all three degradations occurred because an incorrect i resistor was installed on the speed switch's power supply card. This resulted in heat related damage to l the power supply card components. The cited speed switches were supplied by Coltec.  !

The Synchrostart ESSB-4AT speed switch is a standard component in Engine Systems' safety related l EMD diesel generator control systems. As applied by Engine Systems, the speed switch provides a safety related function. Failure of the speed switch could disable generator field flashing, resulting in failure of the diesel generator to build output voltage. Because of the safety related application of the ESSB-4AT speed switch, Engine Systems is sending this notification to all nuclear customers.

COMPONENT:

Synchrostart ESSB-4AT speed switch (p/n SA-2110). l i

CUSTOMERS AFFECTED:

i All nuclear users of EMD diesel generators.

DEFECT:

The speed switch power supply card contained an correctly sized resistor. An 82 ohm resistor was installed in place of the correctly sized 1200 ohm reastor.

CORRECTIVE ACTION:

According to the information contact identified in OE9504, severe heat damage to the power supply card components became visibly evident within the first 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of engine operation. A DC system ground or erratic speed indication occurred after approximately 40 to 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> of operation. The circuitry at Hope Creek only applies power to the speed switch during engine operation. Engine Systems' circuit design applies power to the speed switch continuously (operating as well as standby modes); therefore, speed switch degradation would occur within 3 days following completion of installation. As a result, speed switches with incorrect resistors would have been identified during periodic testing of the diesel generator; therefore, installed speed switches are not suspect.

1. All users with ESSB-4AT speed switches should check their spare ESSB-4AT speed switches to ensure that the correct resistor is installed.

A. Remove the four cover mounting screws.

B. Lift the cover (with attached circuit cards) out of the switch housing.

I.  ;

l: . ,

REPORT NO.'10CFR21-0078  !

l REVISION 0: 1/25/99 l PAGE: 2OF3 l l

• C. Identify the power supply card. ,

i The power supply card is located at the bottom of the cover and is unique because it has  ;

. "fingers"which restin a slotin the switch housing. l ll D. Identify the suspect resistor.

, i i The suspect resistoris the only component mountedin a spnng clip. This resistorshould be 1200 ohms. ' If the resistor markings are not readable, connect an ohmmeter across the resistor (use exposed leads) to venfy resistance (1200 ohms +/- 2%). ,

E. Reinstall cover in housing, making sure that the " fingers" of the power supply card rest in the slot at the bottom of the housing. Install four cover mounting screws and tighten hand (snug) tight.

i i

2. Switches with incorrect resistors should be retumed to Engine Systems, Inc., contact our Customer

' Service department.-

- 3. Switches with correct resistors can be retumed to inventory.

+

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p

I REPORT NO.10CFR21-0078 i REVISION 0: 1/25/99 PAGE: 3 OF 3  !

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EXHIBIT 1 i

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OPERATING EXPERIENCE REPORT OE9504 (2 pages)  !

. SYNCHROSTART ESSB CATALOG CUT (1 page) 1 l

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OPEX oG%04

. i

> > Unit Name: ..................... Hope Creek )

> > Year Commercial: .............. 1986 l

> > NSSS/,A-E: ...... ............. .GE/Bechtel l

> > Rating: ....................... 1117.5

> > Turbine Mfg: ...................GE l

> > Event Date: ................. . 9/23/98

> > Docket No: ........... ........ 50-354

> > EIIS System Code: EK

> > NSSS Applicability: BWR and PWR

> > Maintenance Rule: Yes

> > ABSTRACT:

> > Hope Creek Generating Station has experienced the degradatien of three

> > Synchro-Start speed switches. All three degradations occurred because

> > the switch's internal power supply card contained a wrong sized

> > current limiting resistor. A spare speed switch from inventory was

> >.diso found to contain a wrong resistor. The affected speed switches

> > have different batch numbers, but all contain the same wrong sized

> > current limiting resistor. The cited speed switches were manufactured

> > by Synchro-Start (M/N ESSB-4AT) and purchased through Coltec (P/N

> > 01709876-162).

> > DESCRIPTION:

> > During a planned run of the 'A' emergency diesel generator in

> > September 1998, it was observed that the engine auxiliaries that

> > normally turn on as the engine coasts down cycled on then off 5 to 6

> > times. Corrective maintenance identified several overheated components

> > on the power supply card internal to the speed switch, (Synchro-start,

> > M/N ESSB-4AT). The switch was replaced with a new unit and the

> > degraded switch sent to the original vendor for a root cause

> > determination. A review of the corrective maintenance history

> > indicated that this switch was replaced in March 1998, due to a ground

> > on the 125 VDC control system. Photos of the degraded March 1998

> > switch appear to be identical to that of the degraded September 1998

> > switch.

> > Prior to completion of the vendor evaluation / a planned maintenance

> > outage of the 'D' emergency , diesel generator in October 1998,

> > identified similar evidence of component overheating on the power

> > supply card internal to the switch. The switch calibrated

> > satisfactorily, however based upon the apparent heat related damage,

> > the switch was replaced with a new unit. Following four maintenance

> > test runs and the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> surveillance run, during the hot restart

> > test the analog speed indicators read high. An internal inspection of

> > the switch in the 'D' diesel revealed significant overheating of the

> > power supply components similar to what was observed on the 'A'

> > diesel.

> > The control circuit of each emergency diesel contains an ' electronic

>> speed switch', which controls the sequence / operation of various engine

> > support / auxiliary systems. The diesel speed switch circuitry consists

> > of an engine mounted sensor, a speed switch with four output contacts

> > and two local analog tachometers. Output contacts enable / disable

> > select alarms and control key engine auxiliary components essential

> > for engine and generator operation. (Relays activate functions at 40,

> > 95, 125, and 365 rpm. The analog output is calibrated from 'O' to

> > '750' rpm and normal engine running speed at 514 rpm.)

~_ . - -. ...- - _ . - - - . - _ . - - - _ - . - . - . - - . - . . . . _ - . _ . _ _ , . __

> ' > On-sita b:nch tssting by utility psrsonnsi concludsd that tha cause of

> .> the power supply.degrcdation was an incorrset current limiting

> > resistor installed by the vendor. A portion of the supply consists of

> 2 a 5 VDC circuit which supplies power to the card logic circuits and '

> -> .th'e anal og output control circuit. A current limiting resistor, by

> > design, is suppose to have a value of 1200 ohms. The as found resistor  !

> > in the 9/98 and 10/98 degraded speed switches had an 82 ohm resistor. i

>-> A spare switch from the storeroom was also found to have an incorrect

- > v resistor installed.

'> > The cited speed switches have a serial number listed on the name

> > plate; however, this serial number represents a single ' batch' number

> > which is usigned when a group of switches are fabricated. The ' batch'

> > numbers of the degraded switches are 79116 and 81297.

> > CAUSE:

> . > Wrong current limitiag resistor installed on the power supply card

> > internal to the speed switch 'during the manufacturing process. The

- > ' > original manufacture.r, Synchro-Start, has concurred that the 82 ohm

> -> ' resistor is incorrect and causes the power supply to overheat. (Note:

> > the correct current' limiting resistor should be 1200 ohms.)

> > SAFETY SIGNIFICANCE:

> Engineering has' determined that the cited speed switch degradation

> : > does not impact the ability of the diesel generator to perform its

--> > safety function. A reasonable assurance that the emergency diesel

> > will perform its intended design function is based upon the following:

~

> >+ actual degradations to-date have not impacted satisfactory

>. >- monthly testing 1

> >+ an operability determination which analyzed all possible

> > switch functions against potentia:. malfunctions

> . >+ compensatory action taken at the conclusion of each diemel

> > run

- > > HISTORY:

"> > There have been several Operating Experience documents (OE 5008, OE

- > > 5433.ts CE 5919) involving defective speed switches manufactured by

. >- > Synchro-start, which have symptoms similar to those seen here, but

> .> none of the documents indicate that the degra'dation was due to the use

>. > of a wrong sized resistor.

> > CORRECTIVE ACTIONS:

--> > 1). All speed switches will be replaced with units verified to

- > >z have the correct current limiting resistor.

> >:2). Inventory has been checked to insure that replacement

>>- switches have the correct current limiting resistor. t

> > 3) Notification of-the Nuclear Industry has been made via

( > > this OE.

I >

Subject:

OE9504 - Defective EDG Speed Switches l > >

> > INFORMATION. CONTACT: . George S. Daves (609) 339-3071, gdaves@PSEG.COM i

1 l-I

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