United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 71-02: Rochester Gas & Electric Company



                                                            IEB 71-02

                                 UNITED STATES
                           ATOMIC ENERGY COMMISSION
                            DIVISION OF COMPLIANCE
                                   REGION I
                               970 BROAD STREET
                           NEWARK, NEW JERSEY 07102

                                      December 8, 1971


Rochester Gas & Electric Company                         Docket No. 50-244
ATTN:  Mr. Keith W. Amish, Sr. Vice President
       Electric & Steam
89 East Avenue
Rochester, New York 14604

Gentlemen:

We recently received information relating to the performance of reactor scram
circuit breakers from two licensees operating pressurized water reactors.  The
reactor scram circuit breakers are Westinghouse, type DB-50.  The information
is as follows:

Plant A

Three failures to operate occurred at this facility.  Each failure involved
the undervoltage trip attachment.  No common mode of failure could be
identified.  One failure was attributed to a broken latch pin, the second to
mechanical binding of the trip lever, and the cause of the third was not
specifically identified.

Plant B

Two of the two reactor scram circuit breakers failed to trip on undervoltage
during surveillance testing.  The failure to trip was attributed to dirt
accumulation on exposed linkages.  This failure occurred after completion of
inspection of the scram breakers to determine the applicability of the
problems observed at Plant A.

It is requested that you inform this office within ten days, in writing,
whether reactor scram circuit breakers of the described make and model are
installed in you facility.  If the answer to this question is in the
affirmative, provide the date when each of your reactor scram circuit breakers
will be inspected and tested.  In addition, it is requested that you inform
this office within ten days, in writing, following completion of your
inspection and test, of your specific findings, including a description of
corrective action taken or planned and the scheduled 
.

-                                      2 -

completion date of planned actions.

Should you have any questions concerning this matter, we will be pleased to
discuss them with you.

                                   Very truly yours,



                                   James P. O'Reilly
                                   Director

cc:  Mr. C. E. Platt, Plant Superintendent

bcc:  A. Giambusso, CO
      L. Kornblith, CO
      R. Engelken, CO
      J. G. Keppler, CO (5)
      DR Central Files

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