Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
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
.
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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