Use of casual tree method for investigation of incidents and accidents involving radioactive materials

There are many methodologies used for investigation of accidents to facilitate the search of the factors that cause these events in different areas of industry. These can be called proactive methods, if they are used before the occurrence of the events, or reactive methods that are applied after the occurrence of the incident or accident, and are used as a basis of information to prevent further events. One of these methods is the Causal Tree Method (CTM). The basic idea of this technique is that incidents and accidents result from variations in usual processes. These variations can be related to the individual, the task, the material or the environment. The tree starts with the end event (incident or accident) and works backwards. The facts relating to the end event are used in the construction of the causal tree. The end event is the starting point and only the facts that contributed to the incident or accident should be selected. The analyst has to identify and list the variations and then display them in the analytic tree, showing causal relations. The objective of this paper is to test the application of the CTM method in investigation of incidents and accidents involving radioactive materials, in order to evaluate its efficiency on finding the typical factors causing these events. (author)