THE EVALUATION OF THE LONG-TERM CONSEQUENCES OF A NUCLEAR ACCIDENT INTHE CODE NACOS

To evaluate the long-term consequences of a nuclear accident and to si mulate the effects of countermeasures on the doses received by the pop ulation a terrestrial food chain model was applied in the code NACOS. The linear compartmental model of the migration processes of radionucl ides has been solved analytically applying step-like functions of the parameters. The data base built into the code makes possible the simul ation of seasonal changes and the effects of the countermeasures whene ver introduced. The estimation of the ingested dose for different inte gration periods following the intake is based on an age-dependent dosi metric model. The effect of the seasonality and of the countermeasures on the expected activity concentration in foodstuff and on the ingest ed doses following a unit deposition of I-131 and Cs-137 is demonstrat ed.