Modelling of Radioactive Pollutants: Application of the Detract Code System at the Hanford Scenario

INTRODUCTION The “Hanford Scenario” refers to an acute accidental release of radioactive I from the stack of the Hanford (USA) Purex Chemical Separations Plant that occurred between 2 and 5 of September 1963 (BIOMASS, 1999). From the environmental impact point of view it is a very interesting case study for the evaluation of computational systems that simulate the atmospheric dispersion, deposition and passage to food chain of radioactive pollutants. It is a very challenging case too, because of the surrounding topography is complex, while the release is variable in time and lasts for three and a half consecutive days with changing wind direction and atmospheric stability: frequently temperature inversions occur at night and break during the day, resulting in unstable and turbulent conditions.