United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: COOPER ENERGY SERVICES             

SITE: COOPER ENERGY SERVICES                EN NUMBER:32416

DOCKET:                                  EVENT DATE: 05-30-97

RX TYPE:                                 EVENT TIME: 00:00

VENDORS:                                NOTIFY DATE: 05-30-97

EMERGENCY CLASS: N/A  REGION: 1 STATE: PA      TIME: 14:53

OPS OFFICER: CHAUNCEY GOULD           

10 CFR SECTION: CCCC  21.21               UNSPECIFIED PARAGRAPH

                NINF                      INFORMATION ONLY     



- PART 21 - POTENTIAL MANUFACTURING DEFECT IN COOPER-BESSEMER KSV

EDGs -                                                           

                                                                 

COOPER ENERGY SERVICES MADE A 10 CFR PART 21 NOTIFICATION FOR    

THEIR COOPER-BESSEMER KSV EMERGENCY DIESEL GENERATORS DUE TO A   

POTENTIAL MANUFACTURING DEFECT. THE POTENTIAL DEFECT CONCERNS THE

THICKNESS OF THE PISTON CROWN IN THE VALVE CUTOUT AREA THAT      

PROVIDES CLEARANCE FOR THE INTAKE AND EXHAUST VALVES.  THE       

NOMINAL DESIGN THICKNESS OF THIS AREA IS 0.438, BUT A FAILED     

PISTON HAD AN AREA THAT TAPERED DOWN TO A MINIMUM THICKNESS OF   

0.040.                                                           

                                                                 

FINITE ELEMENT ANALYSIS PERFORMED SUBSEQUENT TO THE FAILURE HAS  

INDICATED AN ACCEPTABLE MINIMUM THICKNESS IN THE VALVE CUTOUT    

AREA OF 0.100.  THE ANALYSIS ALSO INDICATED THAT A 0.040 THICK   

PISTON SHOULD NOT FAIL IN NORMAL OPERATION, BUT THE FACTOR OF    

SAFETY IS BELOW NORMALLY ACCEPTED VALUES. EXAMINATION OF PISTONS 

IN COOPER ENERGY SERVICES STORES NOTED MANY IN THE 0.25 TO 0.31  

RANGE AND ONE AS LOW AS 0.070.  THE ROOT CAUSE OF THE DEFICIENT  

CONDITION WAS AN INCORRECT FOUNDRY PATTERN.                      

                                                                 

THE FOLLOWING PLANTS ARE AFFECTED:  PALO VERDE, BRAIDWOOD, BYRON,

ZION, WATERFORD, SOUTH TEXAS, COOPER, NINE MILE POINT UNIT 2, AND

SUSQUEHANNA.                                                     



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