HomeMy WebLinkAbout851190.tiff SSINS No. 6835
IN 85-93
UNITED STATES
NUCLEAR REGULATORY COMMISSION D)
OFFICE OF INSPECTION AND ENFORCEMENT Cr
WASHINGTON, D.C. 20555 Dec 1 3085
December 6, 1985
IE INFORMATION NOTICE NO. 85-93: WESTINGHOUSE TYPE DS CIRCUIT BREAKERS,
POTENTIAL FAILURE OF ELECTRIC CLOSING FEATURE
BECAUSE OF BROKEN SPRING RELEASE LATCH LEVER
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or a
construction permit (CP).
Purpose:
This information notice is to alert licensees that the electric circuit breaker
closing function of Westinghouse Type DS circuit breakers could possibly malfunction
because of a broken spring release latch lever. It is expected that licensees will
review the information for applicability to their facilities and if the defect
exists, consider actions to determine safety significance and corrective action.
However, suggestions contained in this information notice do not constitute NRC
requirements; therefore, no specific action or written response is required.
Description of Circumstances:
On April 14, 1985, the Westinghouse Nuclear Services Integration Division (NSID)
issued Technical Bulletin No. NSID-TB-85-17 advising their customers of a
potential malfunction in Westinghouse Type DS Class 1E circuit breakers because
of broken spring release latch levers. These electrically operated type DS
breakers will not close electrically when the spring release latch lever has
been broken off. Twenty-five broken levers have been reported and evaluated.
This evaluation shows concentrations of incidents traceable to manufacturing in
the following periods of time: early 1975, April 1976, and early 1978.
This circuit breaker failure, as discussed, adversely affects the safety function
(closing on demand) when the circuit breaker is used in the Engineered Safety
Features Systems. However, this failure mode will not affect the safety trip
function when it is used in the reactor protection system.
Discussion:
The April 14, 1985 Technical Bulletin recommends the following corrective actions
for DS Class 1E circuit breakers: (1) advise the responsible personnel that the
breaker may be closed manually using the operator on the front panel of the
breaker cubicle, if electrical closing does not occur on demand; (2) for
applications other than Westinghouse-designed reactor trip (RT) function, the
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IN 85-93
December 5, 1985
Page 2 of 2
user should evaluate the situation to determine if this condition could affect
safety; and (3) inspect the latch lever during normal scheduled maintenance/
inspection of the DS circuit breaker.
The DS Class 1E circuit breakers also are used in plants not designed by
Westinghouse. Some of these facilities may not have received Technical Bulletin
No. NSID-TB-85-17, therefore, it is suggested that these facilities contact
Westinghouse NSID to obtain additional information on performing the inspections
and corrective action.
No specific action or written response is required by this notice. If you have
any questions regarding this notice, please contact the Regional Administrator
of the appropriate NRC regional office or this office.
iEdwar d L. ordan, Director
Division Emergency Preparedness
and En neering Response
Office of Inspection and Enforcement
Technical Contact: L. B. Parker, IE
(301) 492-7190
Attachment: List of Recently Issued IE Information Notices
Attachment 1
IN 85-93
December 5, 1985
LIST OF RECENTLY ISSUED
IE INFORMATION NOTICES
Information Date of
Notice No. Subject Issue Issued to
85-92 Surveys Of Wastes Before 12/2/85 All production and
Disposal From Nuclear Reactor utilization facilities,
Facilities power reactors,
research and test
reactors holding an
OL or CP
85-91 Load Sequencers For Emergency 11/27/85 All power reactor
Diesel Generators facilities holding
OL or CP
85-58 Failue Of A General Electric 11/19/85 All power reactor
Sup. 1 Type AK-2-25 Reactor Trip facilities designed
Breaker by B&W and CE holding
an OL or CP
85-90 Use Of Sealing Compounds In 11/19/85 All power reactor
An Operating System facilities holding
an OL or CP
85-89 Potential Loss Of Solid-State 11/19/85 All power reactor
Instrumentation Following facilities holding
Failure Of Control Room an OL or CP
Cooling
85-88 Licensee Control Of 11/18/85 All power reactor
Contracted Services Providing facilities holding
Training an OL or CP
85-87 Hazards Of Inerting 11/18/85 All power reactor
Atmospheres facilities holding
an OL or CP; and
fuel facilities
85-86 Lightning Strikes At Nuclear 11/5/85 All power reactor
Power Generating Stations facilities holding
an OL or CP
OL = Operating License
CP = Construction Permit
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