On March 3, 2019, during overhaul activities of the medium voltage power (Magne-blast) circuit breakers, three General Electric Hitachi (
GEH) Stationary Primary Contact Fingers Q0114C5382P002 were identified as having contact surfaces with a finish that was rough and unlike the typically smooth finish provided on electrical contact surfaces. These Stationary Primary Contact Fingers are the primary current carrying device for the circuit breaker.
On October 1, 2019, Arizona Public Service Company (APS) completed an evaluation of a deviation, and concluded the condition represented a defect under 10 CFR 21.
On October 4, 2019, the Palo Verde Nuclear Generating Station Vice President, Nuclear Engineering, was notified of a defect of GEH Stationary Primary Contact Fingers which met the reporting criteria of 10 CFR 21.21.
There are no medium voltage power (Magne-blast) circuit breakers with stationary primary contact fingers impacted by this condition installed in the plant. APS concluded this condition, if installed, could result in the breaker failing to perform its safety function and thus could create a substantial safety hazard.
The NRC resident inspector has been informed.
