• decision-dynamic event tree
• probability
• risk
• combined cycle.
• consequence
• reliability

A dynamic probabilistic risk assessment approach is proposed in this dissertation.
IDDA is a tool based on a decision-dynamic event tree, it allows us to explore all
possible alternative scenarios, on the basis of which we have to make process or
production choices. Each scenario is developed through a logical cause-consequence approach.
Each piece of logical information is used to reduce the theoretical number of
constituents, in order to avoid binary explosion.
After a short introduction to the classical approach to Probabilistic Risk Assessment and to the modern methodologies of Dynamic Reliability, a brief description of the IDDA method is given, providing some explanatory examples.
Furthermore, a reliability analysis for the vapour cycle system within a combined thermal power plant is done. The effect of main components and of human interventions has been evaluated. On the basis of this analysis most critical factors have been revealed and,
moreover, appropriate improvements are proposed.