Part 21 Report - 1998-240

LICENSEE: ILLINOIS POWER CO. SITE: CLINTON 1 EN NUMBER:33800 DOCKET: 05000461 EVENT DATE: 02-26-98 RX TYPE: BWR EVENT TIME: 16:18 VENDORS: GE-6 NOTIFY DATE: 02-26-98 EMERGENCY CLASS: N/A REGION: 3 STATE: IL TIME: 16:18 OPS OFFICER: JOHN MacKINNON 10 CFR SECTION: CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE CODE CRIT PWR PWR 1 N N 0 COLD SHUTDOWN 0 COLD SHUTDOWN 10CFR PART 21 REPORT - DIVISION 2 NUCLEAR SYSTEMS PROTECTION SYSTEM INVERTER NOT IN ACCORDANCE WITH THE PLANT'S DESIGN BASIS DUE TO VARIOUS DEFICIENCIES. WITH THE PLANT IN COLD SHUTDOWN, PLANT TECHNICIANS IDENTIFIED VARIOUS DEFICIENCIES IN THE INSTALLED SILICON CONTROLLED RECTIFIERS (SCR) AND POWER DIODES OF THE DIVISION 2 NUCLEAR SYSTEMS PROTECTION SYSTEM (NSPS) INVERTER. THE COMPRESSIVE FORCE APPLIED TO THE HEAT SINK CLAMP HARDWARE FOR SCRs AND POWER DIODES HAD BEEN APPLIED AND VERIFIED INCORRECTLY, CAUSING LOOSE CONNECTIONS. THEREFORE, THE INVERTER LIKELY WOULD NOT HAVE BEEN CAPABLE OF PERFORMING ITS SAFETY FUNCTION DURING A SEISMIC EVENT. MISCALIBRATION OF THE INVERTER LOCK-UP DETECTOR ASSEMBLY RESULTED IN A LOSS OF THE SIMULATED INVERTER LOADS DURING TESTING UNDER INVERTER FULL LOAD CONDITIONS, WHEREBY LOSS OF THE SIMULATED BYPASS POWER TEST SOURCE RESULTED IN A REVERSE TRANSFER OF THE INVERTER TO THE MISSING BYPASS POWER TEST SOURCE, AND A LOSS OF POWER TO THE SIMULATED INVERTER LOAD BANK. THESE CONDITIONS ARE NOT IN ACCORDANCE WITH THE PLANT'S DESIGN BASIS. A CAUSE EVALUATION FOR THIS EVENT HAS NOT BEEN COMPLETED AND CORRECTIVE ACTIONS HAVE NOT BEEN IDENTIFIED. HOWEVER, THE DIVISION 2 NSPS INVERTER SCR AND POWER DIODE INSTALLATION HAVE BEEN CORRECTED AND OTHER INVERTERS WILL BE INSPECTED FOR SIMILAR DEFICIENCIES AND CORRECTED.

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