Systems usability framework for evaluating tools in safety-critical work

This paper presents a methodology with which evaluation of control rooms in safety–critical industry has been carried out. The results of two cases of evaluation in nuclear power plants (NPP) are presented to elaborate the method thoroughly. The evaluation methodology draws from conventions of human factors and usability evaluation methods but adds an activity theoretical viewpoint by considering different control room functions in a purposeful activity system. A control room has three functions in an activity: instrument, psychological tool, and a communicative tool. The introduced evaluation approach allows understanding of quality of the control room on the level of outcomes it produces, work practices that it consolidates, and the user experience it creates. The evaluation approach is demonstrated by presenting baseline evaluations of two hybrid NPP control rooms that were carried out before major upgrade projects were implemented. Hybrid control room refers to a state in which modern and original hardwired technological solutions are in use simultaneously.