United States Nuclear Regulatory Commission - Protecting People and the Environment

ABSTRACT:

Pilgrim Licensee Event Report 50-293/2001-01 Abstract

Two incorrectly configured relays were installed during the 1999 refueling outage (RFO 12) in the B6 480 VAC bus transfer scheme as part of the Pilgrim Station seismic upgrade program. These relays would have prevented swing bus B6 from transferring to the alternate supply under certain design basis conditions. The inability of B6 to transfer would have prevented the low pressure coolant injection isolation valves from opening to perform their safety function.

The cause for installation of the nonconforming relays was failure to detect the mismatch between the relay label and contact configuration by the manufacturer and by a commercial dedication organization during the qualification process. Corrective actions restored the design basis requirements for the B6 transfer scheme.

This report meets the reporting requirements of 10 CFR 21 for nonconforming materials installed in safety-related applications.

This event occurred at 100 percent reactor power with the reactor mode selector switch in the RUN position. The reactor vessel pressure was about 1035 psig with the water temperature at the saturation temperature for that pressure. This event posed no threat to public health and safety.

END OF ABSTRACT

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