State-of-the-art and lessons learned from safety studies and stress-tests for critical infrastructures

Critical infrastructures are the backbone of modern society and provide many essential goods and services. Recent events have highlighted the vulnerability of these infrastructures to natural hazards and the risk for cascade effects with potentially major and extended socio-economic impacts. The STREST project aims at developing a stress test framework to determine the vulnerability and resilience of non-nuclear critical infrastructures. This report summarizes the state-of-the-art and the lessons learned from post- Fukushima stress tests and safety assessment studies for nuclear power plants, from guidelines for hazard and risk assessment of critical infrastructures, and finally from recent catastrophic events. The turn from 'absolute safety', which is unreachable, to the more realistic concept of 'risk awareness' has been made and several methods for risk assessment are implemented. Further efforts are required towards the harmonisation of methods for the identification of natural hazards for critical infrastructures and for the safety assessment in case of beyond-design (cliff-edge) events, considering common cause failures for multiple unit sites and multiple sites as well as cascade effects in interdependent systems. Where necessary, for instance in the case of floods, hazard assessment should include climate-change projections. Enriched knowledge on the vulnerability of key critical infrastructures and their components together with improved preparedness are key to avoiding future disasters.