Investigating the appropriateness of a decision chart to characterize the level of task descriptions in nuclear power plants

Traditionally, the use of operating procedures is very popular or even mandatory in large process control systems including nuclear power plants (NPPs), commercial airplanes and railway systems. This is because good procedures are very effective in enhancing the performance of human operators who have a responsibility for operating these systems. However, the improvement of an operational safety by providing procedures is meaningful only if human operators are able to properly access necessary information from them. In this regard, it is well known that one of the most significant factors affecting the proper use of procedures is the level of task descriptions, which is directly related to the provision of necessary information what human operators want to know. For this reason, in this study, the appropriateness of a decision chart that allows us to characterize the level of task descriptions is investigated using subjective difficulty scores collected from 98 human operators working in domestic NPPs. As a result, it was observed that there is a significant relation between the level of task descriptions and the subjective difficulty score of human operators. Therefore, it is reasonable to say that the decision chart can be regarded as a starting point to scrutinize the contribution of task description levels to the preparation of good procedure.