An evaluation of climate change scenario for safety assessment of a HLW repository

It might be expected that climate change in the future somehow affects the surface and geological environment around the repository system. Past geological and archaeological evidence shows that, over the past million years, the Korean peninsula have experienced several cycles of climate change (four ice age cycles during the Quaternary, started since about 1.7 million years ago), varying from full glacial conditions to interglacial conditions warmer than or similar to the present condition. The similar pattern of climate change is likely to persist into the future over the timescales relevant to performance assessments since changes similar to those in the past are also expected to occur in the future. Therefore, it could be assumed that the present temperate climate is not the only climate condition in view of long term assessment of the repository system on the contrary of Reference Biosphere concept developed through BIOMASS. A preliminary reference geologic repository concept considering such established criteria and requirements as spent fuel and generic site characteristics in Korea was roughly envisaged in 2003 through the works done at Korea Atomic Energy Research Institute since early 1997, from which a conceptual Korea Reference Repository System for direct disposal of nuclear spent fuel is to be introduced by the end of 2007. According to above basic repository concept, which is much similar to that of Swedish KBS-3 repository, nuclide release from the near-field system has been investigated through the previous study by calculating some possible nuclide fluxes through several possible conduits