This study aims to identify the functional and engineering limitations of underground shelters in Seoul amid the escalating threat of North Korea’s nuclear and weapons of mass destruction (WMD) capabilities, and to propose practical improvement meas...
This study aims to identify the functional and engineering limitations of underground shelters in Seoul amid the escalating threat of North Korea’s nuclear and weapons of mass destruction (WMD) capabilities, and to propose practical improvement measures based on empirical analysis. Seoul, as the nation’s core urban hub concentrating administrative, economic, and cultural functions, faces a high probability of simultaneous mass casualties and paralysis of urban functions in the event of a nuclear or WMD attack. However, most existing civil defense shelters were designed and operated to resist conventional weapons, possessing limited structural resistance against the complex effects of overpressure, thermal radiation, electromagnetic pulse (EMP), and radioactive fallout induced by nuclear detonations.
Accordingly, this study conducted an engineering assessment of Seoul’s underground shelter system and performed quantitative evaluations of its structural and functional performance under a hypothetical nuclear attack scenario, thereby deriving scientifically grounded policy directions. The methodology combined literature review, statistical analysis, international case comparison, and simulation using the NUKEMAP platform. Assuming a detonation near Seoul Station based on North Korea’s 2006–2017 nuclear test yields, the simulation estimated the range of casualties, overpressure zones, and thermal radiation effects. Results showed that a 20-kt explosion could cause direct damage within a 2.3-km radius, resulting in approximately 300,000 fatalities and 700,000 injuries. While shallow underground facilities (less than 10 m depth) were highly vulnerable to blast and heat effects, rock-embedded deep facilities at 30–50 m depth exhibited over 90 % attenuation in shockwave pressure, significantly improving survival probability.
The engineering validation revealed that the average effective area per person (0.825 m²) in Seoul’s shelters is far below the international standards (1.5–3.5 m²), and 14.2 % of the facilities have been in service for more than 30 years. Detailed evaluations of structural durability, airtightness, ventilation, and power/communication protection systems indicated that most shelters do not meet WMD-level protective performance. Accordingly, the study proposed engineering enhancement measures such as reinforcement of blast-resistant structures, EMP shielding above 80 dB, installation of HEPA and activated-carbon filters, establishment of positive-pressure zones, and surge-protection systems for power networks.
Comparative analysis of overseas cases focused on Sweden’s Pionen Center, Finland’s Helsinki underground complex shelters, Switzerland’s Zurich University Hospital and public underground parking shelters, and the United States’ Iron Mountain data-protection bunker. These facilities demonstrate the “dual-use” concept, enabling peacetime utilization and rapid wartime conversion through the integration of protective engineering, urban planning, and information-infrastructure systems. Based on these findings, a phased shelter-development framework for Seoul was proposed: (1) structural reinforcement of existing shallow civil defense shelters, (2) retrofitting of subways, underground roads, and public parking facilities into protective shelters, (3) construction of deep-rock protective complexes at 30–50 m depth in core districts, (4) establishment of a smart evacuation information management system, and (5) introduction of a public-private cooperative maintenance model.
In conclusion, this study empirically verified the structural and functional protective performance of Seoul’s underground shelters and presented comprehensive policy improvement measures grounded in engineering criteria. By linking nuclear-explosion simulations with structural analysis, it provides a scientific foundation for transitioning from space-allocation-based shelter policies to performance-oriented protective strategies. The results contribute to the integration of protective engineering and urban planning, offering practical guidance for future national policies on nuclear and WMD-resilient underground infrastructure.