United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9611260325

POWER REACTOR                                         EVENT NUMBER: 31371

FACILITY: MILLSTONE           REGION: 1      NOTIFICATION DATE: 11/22/96
UNIT:     [ ] [ ] [3]         STATE: CT      NOTIFICATION TIME: 14:05[ET]
RX TYPE: [1] GE-3, [2] CE, [3] W-4-LP        EVENT DATE:        09/25/96
                                             EVENT TIME:      00:00 [EST]
                                             LAST UPDATE DATE:  11/22/96
NRC NOTIFIED BY: JAMES PESCHEL
HQ OPS OFFICER:  STEVE SANDIN
                                                  NOTIFICATION
EMERGENCY CLASS: NOT APPLICABLE
10 CFR SECTION:
CCCC 21.21          UNSPECIFIED PARAGRAPH

UNIT  SCRAM CODE  RX CRIT  INIT PWR  INIT RX MODE  CURR PWR  CURR RX
MODE
 3        N         N         0     COLD SHUTDOWN      0    COLD SHUTDOWN

                               EVENT TEXT

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)

                        (Continued on next page)

FACILITY: MILLSTONE                       PAGE # 2 OF EVENT NUMBER: 31371

BUSSMAN

FRN12, 200KA IR
FRN-R25, 200KA IR
FRN-R30, 200KA IR
FRN-R35, 200KA IR
FRN-R60, 200KA IR"

"CONCLUSION:

THE CRACKS COULD RESULTS 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."

Northeast                               TELECOPIER COVER LETTER
Utilities System                                  (FAX)

[Illegible]

DATE           TIME      TOTAL NUMBER OF PAGES BEING SENT:
                              (Including this page)

               COMPANY
TO:

               DEPARTMENT/ DIVISION

               ATTENTION                     TELEPHONE NUMBER

               TELECOPIER TELEPHONE NUMBER  (INCLUDE AREA CODE)

               NAME                ROOM NO.       TELEPHONE NUMBER*_/
FROM:
               DEPARTMENT/DIVISION

               TELECOPIER NUMBER   (INCLUDE AREA CODE)

_________________________
*_/ IF YOU DID NOT RECEIVE ALL OF THE PAGES PLEASE CALL THIS NUMBER
_________________________

COMMENTS/DIRECTIONS

Northeast Nuclear Energy Company
SUBSTANTIAL SAFETY HAZARD REPORT
November 22, 1996

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.

o    Fifteen different fuse types from three different manufactures
     (Gould-Shawmut, Bussmann, and CEFCO) were found to have axial
     cracks.  The cracks occurred as a result of the brass ferrule
     relieving internal stress.

o    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.

o    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                 Bussmann

          A6Y2 Type II, 10KA IR         FRN 12, 200KA IR
          A6Y5, 200KA IR                FRN-R25, 200KA IR
          TRM25, 10KA IR                FRN-R30, 200KA IR
          A4J10, 200KA IR (2)           FRN-R35, 200KA IR
                                        FRS-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.

If you have any questions regarding this information, please contact Mr.
James K Peschel at (860) 437-5840.  In accordance with 10CFR
21.21(d)(3)(ii), a written report will be provided within 30 days,

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