Conversion of simulated radioactive pollutant gas concentrations for a complex building array into radiation dose

Area of Science:

• Environmental Science
• Radiological Health
• Atmospheric Dispersion Modeling

Background:

• Urban environments with facilities releasing positron emitting gases pose unique challenges for radiation dose assessment.
• Existing models may not fully capture complex building aerodynamics and their impact on pollutant dispersion.

Purpose of the Study:

• To develop and validate methods for converting atmospheric concentration data into effective radiation dose.
• To model pollutant dispersion around complex building arrays, including rooftop recirculation zones.
• To assess radiation dose from inhalation, cloud immersion, and gamma-ray plume contributions.

Main Methods:

• Utilized wind tunnel and ADMS (Atmospheric Dispersion Modelling System) data for complex building arrays.
• Analyzed five years of meteorological data to establish wind direction and speed probability distributions.
• Developed a hemispherical plume cloud model (static and moving) incorporating air build-up factors.
• Extended standard building wake models to include rooftop recirculation zones.

Main Results:

• Developed analytic functions for gamma-ray dose within a hemispherical geometry.
• Created a novel model for pollutant concentration in building wake and rooftop recirculation zones.
• Integrated inhalation, cloud immersion, and gamma-ray plume contributions to determine effective dose.

Conclusions:

• The developed models provide a comprehensive approach to effective radiation dose assessment in complex urban settings.
• The methodology successfully integrates dispersion modeling with dose calculation for positron emitting gases.
• Further application of these models is demonstrated for specific site dose determination.