Nuclide release from an HLW repository: Development of a compartment model

A compartment model, ACGEO, has been developed for the Korean reference Repository System (KRS) for an HLW disposal by utilizing AMBER, a general compartment modeling tool. ACGEO is a flexible and adaptable tool, by which a transient calculation of both a nuclide release and transport in the near- and the far-field of a repository system with various and complex shapes can be carried out. It is expected to be used for the treatment of nuclide transport of a decay chain for safety assessment, as well as for design feedback on the KRS both on a deterministic and a probabilistic bases. Some illustrative cases are also investigated in which the influence of varying the near-field system features on the release of selected nuclides for an HLW repository are examined, in order to demonstrate the usability of ACGEO for feedback to a refined repository concept and for establishing an appropriate safety margin for an HLW repository.