Automatic Generation of Dynamic Event Trees: A Tool for Integrated Safety Assessment (ISA)

The concept of Integrated Safety Assessment (ISA) is described in mathematical terms as the basis of a tool for its practical application to high risk installations with aggressive protections. It incorporates the dynamics of the facility as well as the operating environment, both subject to transitions between different time evolutions due to failures and/or system/operator interventions, with emphasis in deterministic transitions. The methodology can be considered an extension of PSA and accident analysis techniques that replaces the static event tree with a generalized dynamic event tree concept based on the theory of probabilistic dynamics. It is particularly suited to assess software (logic) aspects of protection systems, and can be of particular interest to regulatory agencies.