Part 21 Report - 1998-010

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 Friday, January 31, 2020