Preliminary Study of Microreactor Emergency Planning Zone

This study examines the dispersion patterns of a generic nuclear microreactor accident. The investigation involved a comprehensive analysis of χ/Q values across various receptor distances and directional orientations over time intervals ranging from immediate post-accident periods to 30 days. The computer code ARCON 2.0 was used to perform all simulations for the current study, with a meteorological data of approximately 1 year. Key findings indicate a consistent trend of elevated χ/Q values at a receptor distance of 15 meters, emphasizing the significance of proximity to the accident epicenter in assessing potential environmental impacts. Moreover, a discernible decrease in χ/Q values was observed within the near-field dispersion zone (15 to 50 meters), followed by stabilization in dispersion patterns beyond this range. Comparative analysis revealed notable differences in χ/Q values across different post-accident time intervals, suggesting a convergence towards equilibrium in dispersion trends over time. Future efforts intend to integrate these findings with accident source term data from TRIGA reactors to evaluate Emergency Planning Zone (EPZ) size determination.