A radiological dispersion device is a weapon that combines radioactive material with conventional explosives for spreading radioactive material across an inhabited area. This study is focused on evaluating key parameters in an radiological dispersion device scenario. The calculations were performed to include two different situations: by using explosives and by simple mechanical release. Simulations were conducted with the use of the HotSpot Health Physics Codes. The results suggest the existence of significant correlations between stability classes in scenarios where they evolve with time, producing alternations between them. As long as the stability class remains constant, this latter finding offers the possibility of creating a suitable response, based on temporal evolutions. Therefore, the purpose of this study is to: estimate the size of the potentially affected population, estimate absorbed doses, and estimate the cost-effectiveness in order to help initial responses by providing time-sensitive information about the event. A methodology capable of providing useful information allows prompt decisions and initial assessments of future risks to be made efficiently. This approach can also provide a training environment for the personnel responsible for the decision-making at an early stage of the response.