Part 21 Report - 1997-870

LICENSEE: COOPER ENERGY SERVICES SITE: COOPER ENERGY SERVICES EN NUMBER:33398 DOCKET: EVENT DATE: 12-12-97 RX TYPE: EVENT TIME: 15:30 VENDORS: NOTIFY DATE: 12-12-97 EMERGENCY CLASS: N/A REGION: 1 STATE: PA TIME: 15:30 OPS OFFICER: JOHN MacKINNON 10 CFR SECTION: CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE 10 CFR 21 NOTIFICATION, ENTERPRISE DSR-4 AND DSRV-4 EMERGENCY DIESEL GENERATOR ADJUSTING SCREW FAILURE. ON SEPTEMBER 26, 1997, ENTERGY OPERATIONS RIVER BEND STATION REPORTED THE FAILURE OF AN ADJUSTING SCREW, COOPER ENERGY SERVICES PART NUMBER 1A-7840. THE ADJUSTING SCREW IS A BALL AND SWIVEL ASSEMBLY UTILIZED TO ALLOW FOR ANGULAR MOVEMENT BETWEEN THE ROCKER ARM AND INTAKE AND EXHAUST VALVE STEM OF THE POWER CYLINDER HEAD. THE ADJUSTING SCREW IS ASSEMBLED BY SWAGING A "SWIVEL PAD" ON TO A "BALL". SUBSEQUENT INVESTIGATION DETERMINED THAT THE SWAGING PROCESS AND TOOLING WAS OF A DESIGN THAT ALLOWED FOR "OVERSWAGING" OF THE PAD, REDUCING THE AMOUNT OF FREE ANGULAR MOVEMENT IN THE ASSEMBLY. THIS CONDITION POTENTIALLY CAUSED THE MATERIAL OF THE UPPER EDGE OF THE SWIVEL PAD TO BE OVER STRESSED, AND/OR LIMIT THE ABILITY OF THE ASSEMBLY TO ACCOMMODATE THE REQUIRED ANGULAR MOVEMENT WITH UNDUE STRESS. THE FAILURE OF THE ASSEMBLY WAS THE CRACKING OF THE SWIVEL PAD MATERIAL AT THE UPPER EDGE. THIS FAILURE HAS THE POTENTIAL TO CAUSE AN OPERABILITY CONCERN DUE TO THE ASSEMBLY SEPARATING AND EXCESS CLEARANCE (VALVE LASH) BEING ESTABLISHED WHICH COULD LEAD TO CATASTROPHIC FAILURE OF THE VALVE STEM OR REMAINING BALL PORTION OF THE ASSEMBLY. MULTIPLE FAILURES OF THE ASSEMBLY WITHOUT CATASTROPHIC FAILURE COULD ALSO REDUCE ENGINE OUTPUT DUE TO DECREASED VALVE LIFT. IN ADDITION, LOOSE PIECES OF THE ASSEMBLY COULD CAUSE SECONDARY DAMAGE IN THE ENGINE. COOPER ENERGY SERVICES HAS SUPPLIED THE 1A-7840 ADJUSTING SCREW TO THE FOLLOWING SITES: RIVER BEND, CATAWBA, AND KORI 3 & 4 (KOREA ELECTRIC). CORRECTIVE ACTION: THE SUBJECT ASSEMBLIES AT RIVER BEND STATION HAVE BEEN REPLACED WITH ACCEPTABLE ASSEMBLIES. THE SWAGING TOOLING HAS BEEN CORRECTED TO LIMIT THE AMOUNT OF "SWAGE". ACCEPTANCE CRITERIA ASSURING THE NECESSARY FREEDOM OF THE ASSEMBLY HAS BEEN DEFINED AND WILL BE VERIFIED DURING MANUFACTURE. USER RECOMMENDATIONS: UTILITIES CURRENTLY IN POSSESSION OF 1A-7840 ASSEMBLIES ARE INSTRUCTED TO VERIFY THAT A MINIMUM OF 18 DEGREES OF ANGULAR MOVEMENT FROM CENTERLINE IS AVAILABLE IN ALL DIRECTIONS, WITH NO INDICATION OF ROUGHNESS WHEN MOVING.

Page Last Reviewed/Updated Wednesday, March 24, 2021