Surface storage centre intrusion scenarios

After a given period, surface disposal has to be free from surveillance or special restrictions on use of the land. These conditions are obtained by limiting the activity of stored waste, thus limiting the potential doses to the public during normal evolution of the disposal site and during intrusion. Examination of these intrusion scenarios, corresponding to uncertain events, shows a need to modify dose acceptance criteria, taking account of occurrence probabilities. Three recent studies on French surface disposal sites are examined: -scenario of a road construction at an actual site; - the sinking of a well near a disposal site; - the feasibility of storing radioactive sources (in a surface disposal centre). These studies show the necessity for and difficulties of the probabilistic approach. (author)