The Effectiveness of the disposal system barriers based on comparison with natural radionuclide fluxes to the accessible environment

Miyahara, Kaname  ; Kato, Tomoko 

Complementary safety indicators, such as flux, can avoid uncertainties in the biosphere modeling used to estimate conventional dose or risk. These uncertainties inevitably arise from the assumptions made regarding future human behavior. Natural radionuclide fluxes due to geological processes can potentially be used for this purpose. Radionuclide fluxes from hypothetical repositories are estimated on the basis of models. For the present purpose, the H12 generic conceptual model is selected. At the discharge point from the MWCF to the aquifer, these fluxes are compared with the fluxes of natural radionuclides in such groundwater. The advantage of this particular yardstick is that it does not include any of the complex and highly site-specific processes in the surface environment. This paper discusses the relevance of this yardstick for illustrating the effectiveness of the natural and engineered barriers currently assessed by this model.