SAFEST: A Probabilistic Risk Assessment Toolchain

SAFEST helps modeling and analysing static/dynamic fault trees (DFTs) and reward event trees (RETs). DFTs extend static fault trees and can model spare management, functional dependencies, and order-dependent failures. RETs extend traditional event trees with state rewards and decision-making at states, thus providing upper and lower bounds on the analysis results. 

With BDD-based and probabilistic model-checking techniques, it analyzes DFTs models of complex systems for a wide range of complex measures e.g. "mean-time from degraded state to complete system failure".

Moreover, it allows embedding DFTs within RETs thus allowing integrated analysis of RETs and DFTs. It provides a graphical user interface for creating, generating, simulating, simplifying, and visualising fault trees/event trees.

A variety of case studies, including vehicle guidance systems, train operations in railway station areas, and energy systems such as (nuclear) power plants have been done.