Impact of urban shielding on radiological risk after a hypothetical nuclear event

Abstract

Nuclear events have always represented a threat to societies, and nowadays, the concept of tactical nuclear weapons occupies a prominent place in the field of concern. The actual use of such a weapon has not yet been recorded. However, studies involving computationally simulated hypothetical scenarios are periodically published. This study considers a hypothetical event involving the activation of a tactical nuclear device in an urban area. The central objective was to evaluate the protective capacity of urban structures (buildings) for reducing the radiation dose to which the population may be subjected. Analytical computational simulation was applied to create the event. The threshold dose for deterministic effects is the interest isodose for the scenario that considers a 10 kT power device. The concept of Margin of Safety (MoS) was applied to the results in order to turn them into useful information for decision-makers. Applying MoS allowed to organize the urban structures according to their dose reduction capacity (reduction factors). It can be foreseen that in the case of a real application, the proposed methodology will facilitate the classification of structures distributed throughout the urban area, supporting the decision, especially regarding the prioritization of urban zones, and the type of structure. The results showed that it is useful to discriminate urban structures according to criteria conditioned on radiation doses related to deterministic effects. The discrimination introduces scientific basis to advice and support for decision-making, which may increase confidence levels for decision-makers. Therefore a possible positive impact on the optimization of resources and improved conditions for crisis management can be expected.