Comparison of Mutual Awareness in Analog vs. Digital Control Rooms
Control rooms in nuclear power plants are complex, collaborative working environments rife with potential for human error. As control rooms evolve from analog to digital interface environments, crew communication strategies must change as well. Operators in the analog control room operate the plant and communicate with each other with the help of control boards with large control panels, meters, and switches. Reactor operators could choose a particular set of controls on the particular control board which corresponds to the part of the system of interest. Visual display units (VDU), which became a fixture in the control rooms with the shift to digital human-machine interfaces (HMI), bring benefits for safety and flexibility combining information from various sources. With the increase in automation and the use of digital HMIs operators received their personal sitting workstations where they are able to navigate and operate the plant. The amount of information increased as well as the complexity of monitoring and analyzing the system states. Also computerized systems cause operators to get absorbed by their personal screens and reduce interaction between the crew members. Therefore, the collaboration and coordination of task demands requires vigilance and mutual awareness. The level of automation has an influence on the level of mutual awareness experienced by operators in the control rooms. Teams function to carry out highly interdependent tasks, requiring synthesis and sharing of information to achieve common goals. Improving the performance of the team necessitates the operators to focus on the system, the surrounding environment, and situational awareness about the system states. Collaboration of team members is critical when employing the digital operating systems as the acute awareness of the overall progress of the group and individual activities of the operators drives the team to the desired end-states of the plant operations. Out-of-the loop (OOTL) performance problems can be referred to as the lack of supervisory control, system monitoring, and information processing in the digital HMIs. Under some circumstances Senior Reactor Operators (SRO) struggle to follow the actions of other Reactor Operators (RO) because with the new digital interfaces SROs lose track of how the procedures are carried out by ROs, which results in the loss of three way communication. Mutual awareness plays a significant role in keeping the SROs in the loop of plant operations. This paper will investigate, through literature review and expert interviews, the impact and human errors attributed to the increasing complexity of new digital main control rooms. Comparison of the new digital interfaces with the analog interfaces in nuclear power plants has the potential to shed light on increasing mutual awareness and three way communications between the SROs and ROs. Further, identification of the human errors and human actions can provide beneficial information, suggesting significant and critical improvements that can be implemented in the main control rooms to increase safety and reliability of new technology. Additionally, insights on mutual awareness for analog vs. digital control rooms can serve to improve human reliability.