Estimating changes in radiation exposure and the risk zones size during an urban release event

This study proposes a simple geometrical approach to identify areas of increased vulnerability and high-risk zones during the early stages of a radioactive urban event triggered by a radiological dispersal device (RDD). Rapid estimation of potentially affected areas, their location, and possible size and direction variations due to local atmospheric stability conditions, represented by the Pasquill-Gifford classification, is crucial. We conservatively estimate these zones and the radiological contamination using the trusted HotSpot Health Physics code version 3.1.2. The proposed methodology aims to estimate overlapping contamination areas due to changes in local atmospheric conditions. This provides valuable data for decision-making and strategy development, using computational simulations to reduce risks and minimize environmental impacts in the initial phase of such events. This research impacts urban planning, emergency response, and public safety measures, offering practical solutions to mitigate the effects of radiological dispersal events.