Adapting the notion of natural (geological) barrier for final disposal of low- and intermediate-level radioactive wastes in Romania

According to the Minimum Disturbances Design (MDD) notion by Carl-Olof Morfeldt of Mineconsult, Sweden, any site selection, design and construction of low- and intermediate-level radioactive waste repository should be based on a thorough knowledge of the geological environmental so that the implantation of the disposal facility induce no significant harmful consequences. This work presents the way in which the Romanian program of radioactive waste management was implemented for disposal of low- and intermediate-level radioactive wastes from Cernavoda NPP. Based on geological criteria of selection of lithologic, petrographic, tectonic, seismologic, hydrologic and geo-technic nature, 37 sites were analyzed from which 2 were retained and finally one, Saligny site, was chosen, as the most close to Cernavoda NPP. Also, public acceptance and transport connections were taken into consideration. SUTRA, SWMS-2D and CHAIN-2D codes were applied to analyze the safety and the geological barrier effects. The barrier consists in red clay, a smectitic mineralogic compound. The computation showed that in Saligny vault the maximal tritium extension is kept inside due to the red clay barrier. Geo-technical engineering works were conducted to improve the properties of the loess upper layer which resulted in lowering its sensitivity to moistening and erosion