A potential safety concern was reported regarding failure of the Eaton
Cutler-Hammer Freedom Series Heater Pack due to a possible defect in the
weld which joins the screw terminal to the heater coil. The following conditions could potentially occur:
- Open circuit resulting in loss of current to a pole in the overload relay. If the load was not running at the time of failure, it would draw excessive current during its next attempted start, and either trip the overload or damage the load. If the load was running at the time of failure, it would slow to a stop while drawing excessive current, which would either trip the overload or damage the load.
- If two heaters failed in the same load, a shock hazard could develop due to voltage to ground on the remaining phase.
The affected Heater Packs are H2009B-3 through H2011B-3, and H2012B-3 through H2017B-3. The following NRC Licensees are affected: DC Cook, Vogtle, and Beaver Valley, Framatome-ANP Inc. in Lynchburg, VA.
Corrective actions by the supplier include daily inspection/replacement of weld electrodes, and destructive sample testing. Corrective actions by Framatome include dedication activities that address weld integrity acceptance.
Framatome recommends licensees replace all affected Heater Packs.