Closeout of IE Bulletin 83-01: Failure of reactor trip breakers (Westinghouse DB-50) to open on automatic trip signal

Technical Report · Fri May 01 04:00:00 EDT 1987

OSTI ID:6797247

Foley, W J; Dean, R S; Hennick, A

During startup of Salem Unit 1 on February 25, 1983, the undervoltage trip attachments (UVTAs) of both Westinghouse DB-50 circuit breakers failed to open automatically upon receipt of a valid trip signal from the Reactor Protection System (RPS) on low-low steam generator level. The reactor was tripped manually about 30 seconds later. The manual trip used shunt relays installed in the DB-50 breakers. Similar failures of only one of a pair of DB-50 breakers in series had been reported to the NRC/IE and Westinghouse (W). Because of concern about the event at Salem Unit 1 and previous single failures, the NRC/IE issued Bulletin 83-01 on February 25, 1983. Licensees of operating pressurized water reactors with W Type DB breakers having UVTAs were required to take specific actions. The bulletin was issued for information to all other nuclear power facilities. Evaluation of utility responses and NRC/IE inspection reports shows that the bulletin can be closed out per specific criteria for all of the 50 facilities to which it was issued for action. Malfunctions of the UVTAs were reported for only two sites other than Salem. There are no remaining areas of concern for this bulletin.

• Research Organization: Parameter, Inc., Elm Grove, WI (USA); Nuclear Regulatory Commission, Washington, DC (USA). Div. of Emergency Preparedness and Engineering Response
• OSTI ID: 6797247
• Report Number(s): NUREG/CR-4663; ON: TI87900685
• Country of Publication: United States
• Language: English

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