Some illustrative examples from parametric studies for a reference HLW repository using ACGEO

Spent fuels are to be directly disposed of and the only type of HLW in Korea. According to the basic repository design, which is similar to Swedish KBS-3 repository concept, spent fuel is encapsulated in corrosion resistant canisters, and then emplaced into the deposition holes surrounded by high density bentonite clay in tunnels at a depth of ∼500 m in a plutonic rock (Fig. 1). The objective of this paper is to show how we could show reliability of radiological safety assessment through probabilistic calculation with parameters having uncertainties associated with safety of HLW system. To demonstrate a typical way, possibly among many others, some probabilistic calculation results for nuclide release and transport in the near- and farfield of the repository when such selected key parameters as buffer thickness, nuclide travel length in the fractured rock medium, and initial number of defective canisters are varying are presented. ACGEO, a case file developed by utilizing AMBER, a compartment modeling software package was used for calculation