Dynamic modeling of the cesium, strontium and ruthenium transfer to grass and vegetables.

From 1988 to 1993, the Nuclear Safety and Protection Institute (Institut de Protection et de Sûreté Nucléaire--IPSN) conducted experimental programs focused on transfers to vegetation following accidental localized deposits of radioactive aerosols. In relation to vegetable crops (fruit, leaves, and root vegetables) and meadow grass these experiments have enabled a determination of the factors involved in the transfer of cesium, strontium, and ruthenium at successive harvests, or cuttings, in respect of various time lags after contamination. The dynamic modeling given by these results allows an evaluation of changes in the mass activity of vegetables and grass during the months following deposit. It constitutes part of the ASTRAL post-accident radioecology model.

Comparative study of the PARK and ASTRAL post-accidental decision support software.

The French radioecological assessment model ASTRAL and the German model PARK have been developed to evaluate the radiological situation in the case of an accidental release of radionuclides and a widespread contamination of the environment. For decision makers it is of importance that the results on foodstuff contamination and on dose to humans are in fairly good agreement, when areas of the common border are affected. Therefore a comparative study has been done for two scenarios, assuming accidental releases on 1 June and 1 October. The study indicates that the models' structures and the transfer parameters are in good agreement. Only model principles for root vegetables are different in both models. Significant differences in results on the contamination of foodstuff and on dose to humans by ingestion are caused by different assumptions on dates of harvest and feeding methods of animals. A corresponding harmonization is essential with respect to decision making.