Part 21 Report - 1996-840

LICENSEE: ILLINOIS POWER CO. SITE: CLINTON 1 EN NUMBER:31477 DOCKET: 05000461 EVENT DATE: 12-17-96 RX TYPE: BWR EVENT TIME: 14:30 VENDORS: GE-6 NOTIFY DATE: 12-18-96 EMERGENCY CLASS: N/A REGION: 3 STATE: IL TIME: 15:15 OPS OFFICER: DICK JOLLIFFE 10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE CODE CRIT PWR PWR 1 N N 0 REFUELING 0 REFUELING -CRD SYSTEM INOP DUE TO INCORRECT TORQUE VALUE OF CRD HCU HOLD DOWN BOLTS- ON 11/19/96, WITH THE PLANT IN A REFUELING OUTAGE, THE LICENSEE IDENTIFIED THAT THE TORQUE VALUES SPECIFIED BY GENERAL ELECTRIC FOR THE 3/8-INCH HOLD DOWN BOLTS FOR THE CONTROL ROD DRIVE (CRD) HYDRAULIC CONTROL UNITS (HCUs) EXCEEDED THE MINIMUM YIELD STRENGTH OF THE BOLT MATERIAL. THIS CAUSED THE CRD HCUs TO BE INOPERABLE BECAUSE THE TORQUE VALUE DID NOT MEET SEISMIC QUALIFICATION REQUIREMENTS FOR RESTRAINING THE CRD HCUs DURING A DESIGN BASIS EARTHQUAKE. THE CRD HCU OPERATION WOULD ONLY BE AFFECTED IF A SEISMIC EVENT WERE TO OCCUR DURING PLANT OPERATION. THERE ARE SEVEN 3/8-INCH BOLTS IN EACH OF THE 145 CRD HCUs FOR A TOTAL OF 1015 BOLTS. THESE BOLTS ATTACH THE GENERAL ELECTRIC SUPPLIED CRD HCUs TO STRUCTURAL STEEL SUPPORTS IN THE CONTAINMENT BUILDING WHICH WERE DESIGNED BY SARGENT AND LUNDY ENGINEERING, THE ARCHITECT ENGINEER FOR THE CONSTRUCTION OF THE POWER STATION. THIS CONDITION HAS EXISTED SINCE INITIAL LICENSING OF THE PLANT IN 1987. ALL OF THE 3/8-INCH CRD HCU HOLD DOWN BOLTS HAVE BEEN REPLACED WITH NEW BOLTS AND RETORQUED TO THE PROPER VALUE. A SAMPLE OF THE 3/8-INCH BOLTS THAT WERE REMOVED FROM THE CRD HCUs WILL BE TESTED TO DETERMINE WHETHER OR NOT THEY WOULD HAVE BEEN ABLE TO WITHSTAND A DESIGN BASIS EARTHQUAKE WHILE INSTALLED ON THE CRD HCUs. THIS 10 CFR PART 21 REPORT ONLY APPLIES TO THE CLINTON POWER STATION. IN ADDITION, THE LICENSEE HAS SUBMITTED LER #96-018 AND HAS INFORMED THE NRC RESIDENT INSPECTOR.

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