Disruptive effects on a HLW repository due to uplift-erosion in the distant future

Miyahara, Kaname  ; Inagaki, Manabu; Kawamura, Makoto; Ebina, Takanori*; McKinley, I. G.*

Uplift and erosion cannot be generally precluded in Japan, therefore needs to be treated. In particular, uplift and erosion will cause major disruption of the engineered and natural barriers when the repository is exposed at the ground surface, although erosion of the repository should be excluded for very long times by careful siting and design. In Japan, uplift/erosion scenarios must be analysed, even if they occur far in the future as no assessment cut-off times have yet been defined. For this purpose, an argumentation method is being developed to allow sensible scenarios to be constructed. This paper discusses procedures to derive relevant conceptual models and resultant analyses in a credible manner which illustrates the effectiveness and robustness of the HLW disposal system, using relevant yardsticks based on natural radionuclide fluxes.