United States Nuclear Regulatory Commission - Protecting People and the Environment


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.                             

                                                                 



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