Preliminary analysis of gaseous radiocarbon behavior in a geological repository hosted in salt rock
R. Levizzari, B. Ferrucci, A. Luce
Articolo Rivista internazionale con referaggio
A preliminary evaluation of gaseous radiocarbon ( ¹⁴ C) behavior under geological repository conditions for Italian radioactive high level waste-long-lived and intermediate level waste disposal has been performed. Although in Italy there is still no defined project for a geological disposal facility, current work may support future safety assessment studies for a hypothetical future repository in deep salt rock. In the Italian context of radioactive waste, the percentage of ¹⁴ C bearing waste to be disposed in a possible geological repository is low; irradiated graphite is the most important radiological source. Data about the radiological inventory has been collected to simulate production and migration of gaseous ¹⁴ C in a hypothetical geological repository. Three different conceptual models have been developed and simulated. The first model has considered a preliminary evaluation of the radiological impact referred to the whole inventory; the second and third model have evaluated the impact only due to the irradiated graphite. A preliminary sensitivity analysis has been carried out, highlighting the importance of geometry and of distribution coefficients (K d ) in materials used to seal the disposal underground facility. Results show the possibility to correlate the K d values, the volume and the location of the sealing materials to the amount of ¹⁴ C migrating toward the surface.