Quantitative risk assessment and safety barrier identification for an innovative large-scale liquid hydrogen storage tank concept

Large-scale liquid hydrogen storage is a key enabling technology for the deployment of hydrogen as an energy carrier in low carbon and net-zero energy systems. Improving the safety of such installations reduces accident risk and enhances system reliability, ultimately lowering operational costs across the LH2 value chain. This thesis presents a preliminary quantitative risk assessment of a large scale LH2 storage tank incorporating a novel insulation concept developed within the NICOLHy project framework. The results show that ancillary components are the dominant contributors to overall risk, with jet fires and vapor cloud explosions arising from partial and full bore ruptures representing the most critical scenarios. A complementary qualitative comparison between a state of the art insulation configuration and the proposed novel concept indicates that, despite increased system complexity, the new design provides improved fault tolerance against insulation degradation and air ingress, including the associated risks of boil-off increase, air freezing and formation of explosive mixtures. Finally, appropriate preventive and mitigative safety barriers were identified through a combined review of LH2 storage standards and the ARAMIS project framework. The performance of selected mitigative barriers was evaluated, demonstrating partial risk reduction, with the response time of the leak detection and shutdown system emerging as a key parameter for effectiveness. Overall, this work aims to support the development of robust safety strategies for future large-scale liquid hydrogen storage systems and to contribute to the safe deployment of low-emission energy infrastructures. Given the current scarcity of data and operational experience, the study provides a baseline assessment that can serve as a preliminary reference framework and a foundation for future research, model refinement, and technological development in large-scale LH2 storage safety.