Response Times of Nuclear Power Plant Operations: Comparison of Field and Simulator Data

This report presents preliminary comparisons of field and simulator performance data for nuclear power plant operators. The performance measure used was the time for operators to initiate the first correct manual action in response to an abnormal or emergency event. Response times (RTs) for experienced operators in the simulator were generally shorter and less variable than in the field data. Two classes of events were distinguished, step events which occur suddenly and ramp events which develop more slowly. For all events, the range of RTs was very large, with the 95th percentile RT averaging 5 times the 50th percentile RT. Both the 50th percentile RT and the range were much larger for ramp than for step events in the field, but not in the simulator. To date, simulator events have not modeled the wide variety of circumstances in which field events are embedded, and which are thought to be responsible for the extreme variability of RTs for field events.