United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: INDIANA & MICHIGAN ELECTRIC CO.    

SITE: COOK 1 2                              EN NUMBER:31922

DOCKET: 05000315 05000316                EVENT DATE: 03-10-97

RX TYPE: PWR PWR                         EVENT TIME: 00:00

VENDORS: W-4-LP W-4-LP                  NOTIFY DATE: 03-10-97

EMERGENCY CLASS: N/A  REGION: 3 STATE: MI      TIME: 11:25

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   REFUELING          0   REFUELING      

 2    N       Y    100   POWER OPERATION  100   POWER OPERATION



DC COOK DETERMINED THAT THE STANDARD SMB-00 LIMITORQUE TORQUE    

SWITCH ASSEMBLIES REMAINING IN STOCK WERE ALL MISSING A SPACER.  

                                                                 

                                                                 

ON JANUARY 8, 1997, WHILE INSTALLING A NEW TORQUE SWITCH ASSEMBLY

FOR MOTOR OPERATED VALVE 2-MMO-421, IT WAS NOTED THAT A SPACER   

APPEARED TO BE MISSING FROM THE TORQUE SWITCH. AN INSPECTION OF  

ALL THE STANDARD SMB-00 TORQUE SWITCH ASSEMBLIES REMAINING IN    

STOCK DETERMINED THAT THEY WERE ALL MISSING A SPACER. THESE      

TORQUE SWITCH ASSEMBLIES WERE PART OF A GROUP OF 7 RECEIVED FROM 

LIMITORQUE FOR GENERAL USE AT DC COOK UNDER ASP 18787. A         

CONDITION REPORT WAS WRITTEN TO INVESTIGATE IF THIS WAS A NEW    

DESIGN.                                                          

                                                                 

THE DEFECTIVE LOT OF 7 RECEIVED FROM LIMITORQUE APPARENTLY       

RESULTED FROM A MANUFACTURING ASSEMBLY ERROR AT THE LIMITORQUE   

FACILITY.                                                        

                                                                 

THE DOUBLE POLE TORQUE SWITCH IS A STANDARD CONFIGURATION FOR    

AMERICAN ELECTRIC POWER AND IS USED EXTENSIVELY AT THE DC COOK   

PLANT IN SMB-00 ACTUATORS. THE 7 ASSEMBLIES SUPPLIED UNDER ASP   

18787 WERE PLACED IN OPEN STOCK FOR USE IN THE NEXT VALVE        

REQUIRING ONE. THEREFORE, THE 3 TORQUE SWITCH ASSEMBLIES IN OPEN 

STOCK COULD HAVE BEEN USED IN ANY NUMBER OF SAFETY RELATED       

APPLICATIONS WITH UNKNOWN RESULTS. THE FAILURES IN THE 4 VALVES  

IN WHICH THEY WERE INSTALLED DID NOT RESULT IN ANY SAFETY IMPACT,

HOWEVER, THIS COULD NOT BE GUARANTEED FOR ALL OTHER SMB-00 VALVE 

ACTUATORS IN THE PLANT DUE TO THE LARGE VARIETY OF APPLICATIONS  

FOR THE ASSEMBLY. SINCE IT IS NOT POSSIBLE TO DEFINITIVELY       

EVALUATE ALL POSSIBLE APPLICATIONS FOR SIGNIFICANT SAFETY HAZARD,

IT WAS CONSERVATIVELY DECIDED TO SUBMIT THIS EVENT AS A PART 21. 

                                                                 

ALL 4 OF THE DEFECTIVE ASSEMBLIES WHICH WERE INSTALLED HAVE BEEN 

EITHER REPLACED, OR REPAIRED BY ADDITION OF A SPACER. ALL 7      

ASSEMBLIES WERE RETURNED TO LIMITORQUE FOR EVALUATION ON MARCH   

10, 1997. LIMITORQUE HAS NOT BEEN ABLE TO PREDICT WHEN THEIR     

EVALUATION MIGHT BE COMPLETE.                                    

                                                                 

COPY OF PART 21 SENT TO VERN HODGE.                              



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