United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: NORTHEAST UTILITIES                
SITE: MILLSTONE 3                           EN NUMBER:31371
DOCKET:  05000423                        EVENT DATE: 09-25-96
RX TYPE:  PWR                            EVENT TIME: 00:00
VENDORS:  W-4-LP                        NOTIFY DATE: 11-22-96
EMERGENCY CLASS: N/A  REGION: 1 STATE: CT      TIME: 14:05
OPS OFFICER: STEVE SANDIN             
10 CFR SECTION: CCCC  21.21               UNSPECIFIED PARAGRAPH
UNIT  SCRAM   RX   INIT  INITIAL MODE     CURR   CURRENT MODE
      CODE   CRIT  PWR                    PWR
 3    N       N      0   COLD SHUTDOWN      0   COLD SHUTDOWN  

THE LICENSEE IS MAKING A PART 21 NOTIFICATION.                   
                                                                 
"IN ACCORDANCE WITH 10 CFR 21.21(d)(3)(i), NORTHEAST NUCLEAR     
ENERGY COMPANY (NNECO) IS PROVIDING NOTIFICATION TO THE NRC VIA  
THIS FACSIMILE AND CONCURRENT TELEPHONE CONVERSATION, REGARDING A
POTENTIAL SIGNIFICANT SAFETY HAZARD (SSH) IDENTIFIED AT MILLSTONE
STATION.                                                         
                                                                 
"FIFTEEN DIFFERENT FUSE TYPES FROM THREE DIFFERENT MANUFACTURERS 
(GOULD-SHAWMUT, BUSSMAN, AND CEFCO) WERE FOUND TO HAVE AXIAL     
CRACKS.  THE CRACKS OCCURRED AS A RESULT OF THE BRASS FERRULE    
RELIEVING INTERNAL STRESS.                                       
                                                                 
"DURING COMMUNICATIONS WITH MANUFACTURERS, IT WAS DETERMINED
THAT
THESE DEFECTS HAVE BEEN PRESENT WITHIN THE FUSE INDUSTRY FOR MANY
YEARS AND THAT FUSES MANUFACTURED WITH BRASS ARE SUSCEPTIBLE TO  
THIS DEFECT.                                                     
                                                                 
"NNECO DETERMINED THAT FUNCTIONAL TESTING SHOULD BE PERFORMED ON 
A SAMPLE OF THE FUSES.  THE RESULTS FROM THE TESTING INDICATED   
THAT THE FUSES MET THEIR INTENDED FUNCTION OF INTERRUPTING THE   
CURRENT, HOWEVER TEN OUT OF FORTY SIX FUSES HAD FERRULES         
PHYSICALLY BLOW OFF THE END.  THE FOLLOWING IS A LIST OF THOSE   
FUSES THAT THE FERRULE(S) CAME OFF THE END:                      
                                                                 
GOULD-SHAWMUT                                                    
                                                                 
A6Y2 TYPE II, 10KA IR                                            
A6Y5, 200KA IR                                                   
TRM25, 10KA IR                                                   
A4J10, 200KA IR (2)                                              
                                                                 
BUSSMAN                                                          
                                                                 
FRN12, 200KA IR                                                  
FRN-R25, 200KA IR                                                
FRN-R30, 200KA IR                                                
FRN-R35, 200KA IR                                                
FRN-R60, 200KA IR"                                               
                                                                 
"CONCLUSION:                                                     
                                                                 
THE CRACKS COULD RESULT IN A LOSS OF SAFETY-RELATED EQUIPMENT DUE
TO THE FERRULE COMING OFF OF THE FUSE, WHICH COULD THEN SHORT OUT
OR DAMAGE OTHER SAFETY-RELATED ELECTRICAL DISTRIBUTION.  THIS    
COULD BE A SSH CONCERN THAT SHOULD BE REPORTED THROUGH 10CFR21,  
WITH NOTIFICATION TO OTHER UTILITIES DUE TO THE GENERIC NATURE OF
THE BASIC COMPONENT.                                             
                                                                 
"IN ACCORDANCE WITH 10CFR 21.21(d)(3)(ii), A WRITTEN REPORT WILL 
BE PROVIDED WITHIN 30 DAYS."                                     

Page Last Reviewed/Updated Thursday, March 29, 2012