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U.S. Department of Energy
Office of Scientific and Technical Information

Closeout of IE Bulletin 79-09: failures of GE Type AK-2 circuit breakers in safety-related systems. Final report. [PWR; BWR]

Technical Report ·
OSTI ID:6112437
Twelve failures of General Electric Type AK-2 safety-related circuit breakers reported in 1975, 1978 and 1979 are described in IE Bulletin 79-09. Because of these failures, the bulletin was issued April 17, 1979 to require responses and specific actions by all licensees and holders of construction permits. The failures were attributed to either binding within the linkage mechanism of the undervoltage trip device and trip shaft assembly or faulty adjustment of that linkage mechanism. It was concluded that the twelve failures resulted from inadequate preventive maintenance. Because many occurrences of the same kind happened after 1979, a significant number of later NRC documents which are included in Appendix A were issued. The bulletin has been closed out for 101 of the 129 current facilities which reported either that they had no Type AK-2 breakers in safety-related systems or none with undervoltage trip devices. Proposed followup items for the remaining 28 current facilities are presented in Appendix C. Because followup is based on the requirements of later Bulletins 83-04 and 83-08, Bulletin 70-09 is considered closed.
Research Organization:
Parameter, Inc., Elm Grove, WI (USA)
OSTI ID:
6112437
Report Number(s):
NUREG/CR-3791; ON: TI85900923
Country of Publication:
United States
Language:
English