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Updated Requirements for Control Room Annunciation - An Operations Perspective.
Abstract:
In large, complex process systems such as nuclear power plants, annunciation is used to alert operations staff to important changes in plant conditions that may impact on operational goals. Annunciation, along with the routine monitoring of control room displays, enables operations staff to keep up-to-date with the current plant conditions and predict future plant states.
During major plant upsets, process and equipment state changes can result in the generation of hundreds of annunciation messages. In some instances, this large number of messages may overload the presentation capacity of annunciation media and the ability of operations staff to assimilate them.
This paper summarizes the results of applying task analysis to characterize the use of annunciation by control room operators during major plant transients. The analysis confirms the long-held industry belief that operators are alerted to too many extraneous annunciation messages for immediate management of the upset. The analysis also demonstrates that operators rely on annunciation to alert them to both unexpected and expected changes in plant conditions to successfully manage upsets. In past plant designs, the operational need for annunciation of important expected changes in plant conditions has not been explicitly recognized as a design objective.
This paper reviews the background to the project, describes how upsets were characterized for the analysis, outlines how the analysis was performed and documented, and discusses the analysis findings. The paper concludes by providing suggestions for measuring annunciation effectiveness and by identifying areas for annunciation improvement to better support operator needs.
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