This work explores the foundations of radioecological modelization with environmental assessment purposes. In particular its relation with the theory of dynamic systems, and the basic hypothesis underlying the modelization practices. Some very theoretical considerations are followed by some guidelines for the application of the concepts to specific problems of radiological modelization in assessment of consequences. In particular, the report studies the mechanisms most frequently involved in the radionuclide transfer through the environment, the steps to generate a predictive model, the obtaining of generic parameters and finally the uncertainty analysis of the model. (Author) 41 refs.