ABSTRACT
Communication is defined as the exchange of information while preparing for, or performing work, during NPP control (Barnes et al., 2001). Purposes of communication include maintaining a common understanding between team members and thereby increasing operator reliability. Numerous researches have considered communication and its influence on the effectiveness of teamwork. Studies by Jentsch et al, (1995) and Johannesen et al, (1994) found that teams, who were more effective in their performance, used more standard communication and vocalized more situation awareness observation relative to changing important process parameters and alarms. Communication can result in a unified and accurate team situation model, that, in turn, aids collaborative action planning and is then needed to adjust strategies or to develop new ones to deal with the situation (Ma et al., 2006). Schraagen and Rasker (2001) studied the role of communication in the devel-
opment of the shared mental models of the process situation. Their results showed that communication is not so beneficial in routine situations, when team members know exactly what is going on. In novel situations, however, communication is necessary for operators to respond to environmental cues, to explain to each other why previous strategies will not work in the current, novel situation and then it
permits co-operative determination of new strategies and the prediction of future states. Increasing the level of automation can influence and improve communication between team members (Johannesen et al., 1994). However, new control room designs also can impose challenges on team working. Norros and Savioja (2004), noted, that transition to ‘soft control’ can diminish the horizon of observation and hinder information exchange. One of the methods for measuring team communication is to categorize
communication types and then quantify communication in accordance with the categorization. Schraagen and Rasker (2001), for instance, considered and estimated different communication categories such as information exchange, determining strategies and performance monitoring. Barnes et al (2001) studied the communication errors and showed that a verifi-
cation feedback serves an important error-checking function in the communication process. Through feedback the similarity of the meanings given to the message by the sender and understood by the receiver can be verified. An example of feedback in verbal communication is when the receiver ‘repeats back’ the message and the sender either agrees with the receiver’s repeat back or corrects it. Today, communication more and more plays an additional role in that it is used
as a means for increasing the reliability of human operations and particularly, to avoid operator errors. After the series of accidents at NPPs during the 1970s and 80s the emergency management procedures tend to be more strictly formalized and structured. In order to implement the next step in a procedural sequence, the unit shift supervisor has to read the required step’s wording out loud. Then, the appropriate operator (reactor operator or turbine operator) executes this step and reports back about any obtained results. Such a protocol, contributes to increasing the reliability of operator actions. However, this kind of communication is superimposed on the regular exchange of information between MCR operators, field operators, plant specialists and power grid dispatchers. This requirement thus increases the frequency and intensity of communication traffic which can overload the information transmission between operators. As a rule, the emergency procedures are used under stress conditions and under time pressure. In such situations, the communication in itself may be subject to errors and the operators are forced to find ways for optimizating the message exchange. This paper is devoted to the analysis of the communication which takes place
betweenNPPMCRoperatorswhenmanaging abnormal events.The paper considers the categorization and the structural models of various types of communication acts, the estimation of relative proportions of the various communication types, the analysis of factors preventing communication, and a description of methods used by operators in order to facilitate communication.
