ASTRAL : a code for assessing situations after a nuclear accident.

C. Mourlon, Ph. Calmon 12th annual meeting of SETAC Europe, cahllenges in environmental risk assessment and modelling: linking basic and applied research , Vienne (Autriche), 12-16 mai 2002.

Whether for studying impacts of a hypothetical nuclear accident or for handling a crisis situation, experts and decision-makers, after a large scla atmospheric radioactive release, want to assess the contamination of the environment and food products, derive from it the potential exposure of populations to ionized radiation, predict the evolution of the situation and propose different scenarios for the management of contaminated zones. Starting from estimations or measurements of a radionuclide deposit on the ground, the ASTRAL computer code meets these demands. It calculates the evolution of pollutants' concentrations in the food chain components by the modelling of the transfers between differnet compartments of the environment. It also calculates doses received by man, which represent the impact on health; the pathways taken into account are the external exposition to radiation and the internal intake of radionuclides due to inhalation of resuspended material and ingestion of contaminated foodstuff. Furthermore, various counter-measures can be simulated and therefore the efficiency of different managements of contaminated zones and products can be evaluated. A second version of ASTRAL, developped under quality assurance, has been released at the end of 2001 ans is installed in the IRSN crisis technical center and in EDF. For this version, the choice of an internet architecture was made: it enables quick viewing of results, intuitive ergonomics - thus requiring a minimized training - and facilitates the spreading of the software, since only a web browser is necessary for the customer.