Mental causal models of incidents communicated in licensee event reports in a process industry

In English The present investigation describes some mental causal models used in incident reports. Some of the models (e.g., single-cause models) are simpler than others (e.g., causal-tree models). The models are also associated with different ways of explaining an incident or accident and with different recommendations for increasing the safety of a system.
In study 1, incident reports from Swedish nuclear power plants known to use human or organisational factors were analysed. The analysis showed that the most frequent model was a simple single-cause model and that the remainder were usually two-step models leading to a reported event. Multiple cause and more complex models were less frequent.
Study 2 analysed all licensee event reports (including those reports not related to human organisational factors) from four reactors assessed by regulators during the year. The results showed that single-cause and two-step accident models were more frequent than more complex models. The analyses also revealed that different detection modes were related to different models.