Detailed Study of Emergency Diesel Generator Performance Using EPIX/RADS Database

A recent report was published by the U.S. Nuclear Regulatory Commission – Industry-Average Performance for Components and Initiating Events at U.S. Commercial Nuclear Power Plants, NUREG/CR-6928. That report characterized industry performance (generally covering 1998 – 2002) for 51 component types found in commercial nuclear power plants. For example, for emergency diesel generators, three failure modes were identified: fail to start and reach rated speed and voltage, fail to load and run for one hour, and fail to run beyond one hour. Data from the U.S. industry contained in the Equipment Performance and Information Exchange (EPIX) database maintained by The Institute for Nuclear Power Operations were used to evaluate the failure probabilities and rates for these failure modes, covering 1998 – 2002. The software package Reliability and Availability Database System (RADS) was used to search and process the EPIX data. In addition, train test and maintenance unavailability was characterized for 34 train types. As a follow-on effort to this report, several components will be analyzed in more detail each year. These detailed studies include more recent data and analyze various subcategories such as manufacturer, system, size and type (as applicable). In addition, engineering insights such as piece part contribution to each failure mode and failure cause will be determined. This paper summarizes the preliminary results for emergency diesel generators. EPIX data coverage was expanded to include 1998 – 2007 and reliability results were compared with unplanned demand performance (bus under voltage events requiring the emergency diesel generator to start, load and run) over the same period. In addition, performance by manufacturer was evaluated. Finally, piece part contributions and failure causes were determined for each failure mode