Intermediate Results from a System-Theoretic Framework for Mitigating Complex Risks in International Transport of Spent Nuclear Fuel

The challenges surrounding the safety, security and safeguards (3S) of international transportation of spent nuclear fuel (SNF) in today’s dynamic environment demonstrate growing risk complexity surrounding the nuclear fuel cycle (NFC). Interdependencies between 3S risks and dynamic (and emergent) effects on risk make the use of traditional risk analysis methods challenging. In response, this research evaluated the ability of system-theoretic frameworks to better assess, manage, mitigate, and reduce the complex risks associated with international SNF transportation. Invoking two analysis techniques, the gaps, interdependencies, conflicts, and leverage points resulting from an integrated 3S SNF transportation analysis are evaluated to determine any potential benefit over traditional methods that rely on analyzing each ‘S’ in isolation. The first analysis technique, dynamic probabilistic risk assessment (DPRA), uses dynamic event trees to systematically evaluate scenarios arising from various sources of uncertainty to characterize the risk complexity of international SNF transportation. The second technique, system theoretic process analysis (STPA), incorporates system and control theory to evaluate complex systems as hierarchical control structures in order to characterize international SNF transportation risk complexity in terms of emergent system properties. These novel analysis techniques provide the basis for a robust and technically rigorous evaluation of integrated 3S approaches to understand and mitigate complex risk.