Qualification Of Modern Electrical Products To Original Plant Specifications

DISCUSSION Since the construction of most nuclear power generating stations, engineering thermoplastics have replaced many original materials of construction, manufacturer designs have changed significantly and product specifications have evolved to reflect modem product requirements. Whereas many material changes provide improved thermal stability, most manufacturing changes add difficulty to the qualification process. An additional set of hurdles is established by the changes in applicable industry standards such as UL and NEMA. The following discussion focuses on the influence of design and standard changes on the qualification of replacement and retrofit items. Although the paper presents motor control center (MCC) and circuit breakers as examples of the necessary qualification analysis and test programs, most other Class 1E equipment have experienced similar changes.