Bor katkılı kum-bentonit karışımlarının termal karakterizasyonu

Due to increasing energy demand in the world, an increase in the diversity of energy structures is observed. In recent years, there has been a focus on energy structures such as energy piles, geothermal energy plants and nuclear power stations. These thermo-active structures cause temperature increases in soil. Because of these temperature differences, changes in soil parameters occur and as a result of these changes, the mechanical, hydraulic and thermal properties of the soil do not meet the expected performance limits and causing damage to energy structures. Soil thermal conductivity coefficient, heat diffusion coefficient and heat storage capacities are the parameters controlling the heat transfer mechanism in soils. Therefore, in this thesis, thermal conductivity coefficients of boron added sand-bentonite mixtures and usability of these mixtures as a buffer material in the disposal repositories of high grade radioactive wastes (HLW) were investigated. In addition, the effects of thermal conductivity coefficient, volumetric heat capacity and heat diffusion coefficient values on heat conduction, which have a role in heat transfer mechanism, have been investigated. Instead of bentonite material used as a buffer around canister where waste is stored in nuclear waste reposorities, boron added sand-bentonite mixtures were used in this thesis, single and double layer structures were designed separately and analyzed with the help of two different computer program using finite element method. According to the results obtained from this study; the lowest and highest thermal conductivity values were obtained in mixtures containing five percent and fifteen percent tincal, respectively. The maximum temperature in the buffer layer was calculated seventeen degrees lower than that of bentonite alone.