Report on the proposed engineering risk assessment methodology for stress tests of non-nuclear CIs

Abstract

An engineering risk-based multi-level stress test, named ST@STREST, is proposed herein aimed at enhancing procedures for evaluation of the risk exposure of critical non-nuclear infrastructures against natural hazards. In order to account for diversity of types of critical infrastructures (CIs), the potential consequence of failure of the CIs, the types of hazards and the available human/financial resources for conducting the stress test, each Stress Test (ST) level is characterized by a different scope (component or system), and by a different complexity of the risk analysis. The ST@STREST workflow is composed of four main phases and nine steps to be conducted sequentially. First the goals, the method, the time frame, and the total costs of the stress test are defined. Then, the stress test is performed at component and system levels; then, the outcomes are checked and compared to the acceptance criteria. A stress test grade is assigned and the global outcome is determined by employing a grading system proposed herein. According to the outcome the parameters of the following evaluation of stress test are adjusted. Finally, the results are reported and communicated to stakeholders and authorities.