Bentonite, a material mainly used in buffer and backfill of the engineering barrier system (EBS) that makes up the deep geological repository, is a porous material, thus porewater could be contained in it. The porewater components will be changed through ‘water exchange’ with groundwater as time passes after emplacement of subsystems containing bentonite in the repository. ‘Water exchange’ is a phenomenon in which porewater and groundwater components are exchanged in the process of groundwater inflow into bentonite, which affects swelling property and radionuclide sorption of bentonite. Therefore, it is necessary to assess conformity with the performance target and safety function for bentonite. Accordingly, we reviewed how to handle the ‘water exchange’ phenomenon in the performance assessment conducted as part of the operating license application for the deep geological repository in Finland, and suggested studies and/or data required for the performance assessment of the domestic disposal facility on the basis of the results. In the previous assessment in Finland, after dividing the disposal site into a number of areas, reference and bounding groundwaters were defined considering various parameters by depth and climate change (i.e. phase). Subsequently, after defining reference and bounding porewaters in consideration of water exchange with porewater for each groundwater type, the swelling and radionuclides sorption of bentonite were assessed through analyzing components of the reference porewater. From the Finnish case, it is confirmed that the following are important from the perspective of water exchange: (a) definition of reference porewater, and (b) variations in cation concentration and cation exchange capacity (CEC) in porewater. For applying items above to the domestic disposal facility, the site-specific parameters should be reflected for the following: structure of the bedrock, groundwater composition, and initial components of bentonite selected. In addition, studies on the following should be required for identifying properties of the domestic disposal site: (1) variations in groundwater composition by subsurface depth, (2) variations in groundwater properties by time frame, and (3) investigation on the bedrock structure, and (4) survey on initial composition of porewater in selected bentonite The results of this study are presumed to be directly applied to the design and performance assessment for buffer and backfill materials, which are important components that make up the domestic disposal facility, given the site-specific data.

Sorghum (Sorghum bicolor (L.) Moench) has been cultivated for cereal grain which has been traditionally used for steaming with rice in Korea. Various Korean sorghum varieties have been developed and distributed for farmers and consumers to meet their needs. Korean sorghum grains have been mostly sold at higher price in the market than sorghum grains imported from abroad. However, no varietal identification method was established to support fair trade in the cereal market. The objective of this study is to develop the identification method of Korean sorghum varieties using a multiplexed fingerprinting platform of SSR markers. One marker for the waxy allele and nine SSR markers were carefully selected based on their product sizes for the multiplexing. A robust multiplexed combination was revealed from serially designed experiments for the optimization of multiplex PCR. Five varieties and two elite breeding lines could be separated with their unique fingerprinting pattern from other sorghum individuals collected over the world. The platform separated most of individuals tested in this study, remaining three genotypes contained two or three identical individuals. The technique may be applied to detect closely-related individuals including full sibling progeny