Evaluation of the Impact and Inter-Generation Risk Transfers Related to the Release and Disposal of Radioactive Waste from the Nuclear Fuel Cycle: A Methodological Exercise

Reflections about the consequences of decisions involving the long term raise various theoretical and complex issues related to the validity of the quantitative assessment of what could be future risks, but also to the ethical position we are adopting towards future generations. In this perspective, decision-making in the field of radioactive waste management, with a view to maintaining present and future radiation exposures as low as reasonably achievable, implies being able to discriminate among alternative options, i.e., being in a position to evaluate the differences in terms of radiological impacts between the options. Because of the complex and multidimensional nature of the distant future consequences of waste management options, their comparison involves expressing these impacts using various aggregated or disaggregated indicators, taking into account the time during which radionuclides remain in the environment and their local, regional, or world-wide dispersion. This paper is an attempt to contribute to the development of such a framework. It is mainly focused on the risk transfer dimension inherent to waste disposal management. Any decision to protect people now against the potential impacts of radioactive releases into the environment leads inevitably to the exposure of current generations and potentially of future generations. In this perspective, one of the key questions related to waste management is to decide on the best compromise between present dilution-dispersion into the environment or concentration in surface or underground disposal sites. The objective of this paper is to illustrate, the relative impact of different waste management options, focusing especially on inter-generational risk transfers. For the sake of the exercise, calculations have been performed for six particular radionuclides and for the current waste management options combining underground disposal and releases as well as for extreme alternative waste management options, which have never been implemented or envisaged as such in reality: i.e. underground disposal of C-14, Kr-85 and I-129 or, total release, either in the sea or in the atmosphere, of Cs-137, Pu-239 and Np-237. As the alternative waste management options analysed are of a one-off nature, it leads to some extremely high exposures such as for the integral release of Cs-137. But between total disposal and total release, many options are available, which have to be evaluated in an ALARA perspective. Based on these evaluations, the indicators characterising the radiological impacts are discussed taking into account the time and space dimensions. Individual and collective doses associated with the present and future generations are presented for the different options and their usefulness for evaluating these options is considered. In this perspective, this kind of time and space presentation provides useful information for helping decisionmaking processes and facilitating the communication with non-specialists.