Assessment of environmental radioactive surface contamination from a hypothetical nuclear research reactor accident

Abstract

The environmental surface contamination by radioactive elements following a nuclear research reactor hypothetical accident is evaluated employing the hotspot code, IAEA safety guide, and NRC guidelines. Gaussian plume depositions of radioactive contaminants are calculated under very conservative assumptions for a worst-case accident scenario, and site most probable wind speed and metrological conditions. Results reveal that the contamination strongly decreases with distance, dropping seven orders of magnitude from 2.2E+09 kBq/m2 at the reactor site to 9.5E+2 kBq/m2 60 km from the reactor at the plume centerline. In rainy weather, the wet deposition is depleted to 6.0E+2 kBq/m2 after 50 km, limiting the spread of contaminants to a much smaller area. Although the results of this work tend to overestimate the surface deposition of radionuclides, they present a clear insight into the radiological consequences of nuclear accident worst-case scenario. Thus, it assists with the development of a comprehensive emergency preparedness program by identifying all areas with potential risk to contamination.