Part 21 Report - 1996-800

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."

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