United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9712100072



                                        Illinois Power Company

                                        Clinton Power Station

                                        P. O. Box 678

                                        Clinton, IL 61727

ILLINOIS                                Tel 217 935-5623

POWER                                   Fax 217 935-4632

An Illinova Company

                                        John G. Cook

                                        Senior Vice President



                                        U-602876

                                        4F.140



                                        December 3, 1997



Docket No. 50-461                       10CFR21.21



Document Control Desk

Nuclear Regulatory Commission

Washington, D.  C.  20555



Subject:  10CFR21 Interim Report 21-97-044/047/048:

          Deviations in Safety Related Battery Chargers



Dear Madam or Sir:



     On September 29, 1997, the Division 2 safety-related battery charger

failed to operate as expected.  Operators received an alarm in the Main

Control Room indicating low Division 2 DC bus voltage.  Indications also

included 0 amps output from the Division 2 battery charger, and DC bus

voltage stabilized at about 128 VDC which is the expected voltage for a

loss of the battery charger.  An electrician was dispatched to the

Division 2 battery charger to investigate the problem and noted that the

charger appeared to be stopping and starting itself "electronically"; the

DC voltage and output current decreased to 0 and then returned to normal.

The self starting and stopping of the charger occurred 4 times over

approximately a 30 minute period before the charger was secured for

troubleshooting.



     On October 4, 1997, as a result of troubleshooting Illinois Power

(IP) identified inadequate soldered wire connections throughout the

battery charger.  Specific examples include solder connections on the

Silicon Controlled Rectifier (SCR) firing circuit boards and on wiring

connections for the SCR firing circuit.  This issue was determined to be

potentially reportable under 10CFR21; Condition Reports (CR) 1-97-10-090,

1-97-10-123, and 1-97-10-201 were initiated to track investigations and

resolutions of these issues.



     On October 15, 1997, during further troubleshooting, IP noted 2

anomalies with the High Voltage Alarm (Shutdown) (DSHV) circuit card.

The time delay for the circuit card was approximately 6 seconds rather

than 30 seconds per the purchase specification, and the reset voltage

setpoint of the DSHV was too low to allow the DSHV circuit card to reset

during a momentary voltage transient while the battery charger was in the

equalize mode.  This issue was determined to be potentially reportable

under 10CFR21; CR 1-9710-241 was initiated to track an investigation and

resolution of this issue.



                                                       U-602876

                                                       Page 2



     In addition, during bench testing on October 15, 1997, a new DSHV

circuit card from stores failed to provide an output.  The circuit card

was being tested prior to installation to determine its output response

time.  During the testing, the trip setpoint voltage was reached and the

LED indication illuminated; however, the card failed to provide the

required output for the alarm and trip functions.  This issue was

determined to be potentially reportable under 10CFR21; CR 1-97-10-249 was

initiated to track an investigation and resolution of this issue.



     These conditions may also be applicable to the Divisions 1 and 4

safety-related battery chargers.  The Divisions 1, 2, and 4 safety-

related battery chargers are Model 3SC-130-300, supplied by Power

Conversion Products, Inc.  The DSHV reset voltage setpoint was provided

by Sargent & Lundy.



     IP's evaluation of these conditions under 10CFR21 has not yet been

completed.  IP does not have a firm date for resolving this issue but

will provide, as a minimum, an update on the resolution progress by

January 29, 1998.



     Additional information about this issue may be obtained by

contacting M.  D.  Wagner, Plant Engineering, at (217) 935-8881,

extension 4071.



                                        Sincerely yours,



                                        J.  G.  Cook

                                        Senior Vice President

RSF/krk



cc:  NRC Clinton Licensing Project Manager

     NRC Resident Office, V-690

     Regional Administrator, Region III, USNRC

     Illinois Department of Nuclear Safety

     INPO Records Center

     Power Conversion Products, Inc.

     Sargent & Lundy



*** END OF DOCUMENT ***


Page Last Reviewed/Updated Thursday, March 29, 2012