One of the permanent concerns in the international scenario is the study of the consequences of nuclear and radiological accidents and other events that lead to the contamination of the environment and the exposure of members of the public as a consequence of this contamination. Decision-making in such situations need to be based in solid technical criteria but must also take into account the actual prevailing circumstance in order to reach optimized measures to protect people and the environment. The Multi-criteria Analysis Method is already being used for similar applications in some European countries but it is necessary that the criteria are established taking in account economic, social and climatic aspects that can affect the selection of protective measures applicable to specific regions, and the selection of the different weights to be associated to the different criteria that are to be applied to different social-politic environments. The present work describes the developments to support the decision making process for the implementation of protective measures to protect the public in situations of radiological accidents in Brazil, the steps already developed and the current status of the system under development, discusses the difficulties found and stresses the needs for future developments.

Since the 90’s the relevance of considering environmental aspects in development industrial activities has been steadily growing. The anthropocentric philosophy of radiological protection has been questioned and research and development on ecological risk assessment has now an import role in overall risk assessment procedures. However, most development up to now has focused temperate climate country biota and cannot be directly applied to tropical climate countries, due to the very different environmental characteristics and biodiversity. A preliminary survey focusing the area surrounding the Brazilian nuclear power plant site has shown that very few of the ICRP’s reference animals and plants can be used to characterize environmental protection in tropical climate areas. The development of such lists and all the research needed on parameter values to fulfill a risk assessment procedure would be extremely expensive, and more pragmatic approaches are needed to turn the process reliable in a more global way.

The new technologies of operative monitoring of spent nuclear fuel (SNF) condition at the bottom seas and search for the lost objects with SNF at the bottom using Kr-85, are developed. The development of the ship low-level background complex (Kr-85, tritium etc.) for radionuclide anomalies searching in the sea is launched also. The purpose of a carried out stage of researches is the development new paradigm of sea radioecology based on a preliminary experimental research of kinetics of release fission products (85Kr and 137Cs) from SNF, with the subsequent realization expedition (including preliminary radionuclide measurements on a vessel!) and modeling researches of 85Kr transport in near-bottom layer for minimization of points of sampling (stations and working horizons) on the hydrological data of expedition area (with use of a fractal formalism). Final result of the project is the conservative estimation of risks to the population and environment at its pollution in case of release of a radioactivity from dumped ship reactor and NPS with the not unloaded SNF.