United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: EATON CUTLER-HAMMER
SITE: EATON CUTLER-HAMMER EN NUMBER: 36428
DOCKET: EVENT DATE: 11-12-99
RX TYPE: EVENT TIME:
VENDORS: NOTIFY DATE: 11-12-99
EMERGENCY CLASS: N/A REGION:0 STATE: TIME: 09:58
OPS OFFICER: DICK JOLLIFFE
10 CFR SECTION: CDEG DEFECTS/NONCOMPLIANCE

10 CFR PART 21 REPORT -

Eaton Cutler-Hammer personnel identified a potential safety concern involving the potential for the malfunction of the Eaton Cutler-Hammer DS and DSL Class 1E circuit breakers due to the improper application of zinc chromate plating to hardened parts during breaker reconditioning.

The failure of hardened parts to maintain their design integrity due to cracking and the potential for the total separation of pieces during a seismic event or normal operation and their subsequent infiltration of the breaker operating assembly could cause the failure of the breaker to perform its design function.

In addition, mechanical interlocks may not perform as expected or the breaker may not be able to be charged depending on the actual failure which could occur.

The installed base of the DS style circuit breakers is spread throughout the nuclear industry. However, it is unknown to Eaton Cutler-Hammer specifically which utilities may have had reconditioning performed on their breakers that included plating of parts.

Eaton Cutler-Hammer recommends that a thorough inspection be conducted on all breakers which may have undergone previous reconditioning activities which included plating or replating of component parts. Specific attention should be directed toward spiral pins, which are constructed of hardened spring steel.

See the Eaton Cutler-Hammer Part 21 report for additional details

Page Last Reviewed/Updated Thursday, March 29, 2012