Protection of the natural environment - philosophy and criteria

Nuclear operations give rise to small releases of radionuclides to the environment either under controlled conditions (immediate releases) or uncontrolled from waste repositories in the near or far future (delayed releases). The radiation doses to man from the discharges can be estimated using radioecological and dispersion modelling methods. The system for limiting exposure of individual members of the public is currently based on the recommendation by the ICRP. Their risk philosophy, which stems from the fact that the probability of cancer resulting from radiation will be linear with dose, has hitherto gained broad acceptances for setting authorised dose-limits for man. A discussion has recently emerged on the protection of the natural environment from harmful radiation effects. In this case there is concern for the viability of the population rather than the individuals. As our understanding of important mechanisms regarding the protection of the environment is limited it seems appropriate to adopt a precautionary approach. In matters where little is known about the risks the precautionary principle has a major role to play. Concomitantly, the best available technology (BAT), as stated in the precautionary principle, could be employed to minimise discharges of radionuclides. The development of a regulatory frame-work requires that an objective is set and that standards and indicators are derived in a multi-tiered approach. By applying the precautionary principle for environmental radiation protection the safety margins have to increase. However improving knowledge may in due time lead to more rational decision-making