Investigation of the importance of site-specific fauna in environmental risk assessment for routine atmospheric radionuclidesreleases

International audienc

UDINEE: Evaluation of multiple models with data from the JU2003 puff releases in Oklahoma City. Part I: Comparison of observed and predicted concentrations

In a complex environment, such as an urban area, accurate predictions of the atmospheric dispersion of airborne harmful materials, like radioactive substances, are necessary for establishing response actions and assessing risk or damage. Given the variety of urban atmospheric dispersion models (ADMs) available, evaluation and inter-comparison exercises are vital to assess quantitatively and qualitatively their capabilities and differences. To that end, the European Commission/Directorate General Joint Research Centre (EC/DG JRC) in support to EC/DG-Migration and Home Affairs (HOME), and with the contribution of the U.S. Defense Threat Reduction Agency (U.S DTRA), launched the Urban Dispersion INternational Evaluation Exercise (UDINEE) project. Within UDINEE, nine ADMs have been evaluated and inter-compared. Sulphur hexafluoride (SF6) concentrations from puff released near the ground during the Joint Urban 2003 (JU2003) field experiment are used in UDINEE to evaluate ADMs. JU2003 was chosen because UDINEE aims at better understanding of modelling capabilities for Radiological Dispersal Device (RDD) in urban areas, and the neutrally buoyant puff releases performed in JU2003 are the closest scenario to this purpose. The simulation of the dispersion of puffs is particularly challenging. The results of UDINEE could therefore constitute a benchmark against which future model developments could be compared. The present study evaluates the models’ capability to simulate the presence and concentration levels of the tracer at sampling locations. The simulation of the time-integrated concentrations for each puff and sampler is also evaluated, as it is representative of a dose estimate, which is among the most important impact parameters for population protection.JRC.G.10-Knowledge for Nuclear Security and Safet