Measurement of thermal conductivity of buffer materials and evaluation of existing correlations predicting it Original Research Article

The paper concerns the measurement of thermal conductivity of buffer materials and the evaluation of existing correlations predicting their thermal conductivities. A thermistor probe method developed by the authors was used to measure the thermal conductivity of bentonite and mixtures of bentonite and silica-sand with different densities, water contents, and sand volume. The present and existing thermal conductivity data were compared with various existing correlations. As a result, it is found that the correlation proposed by Sakashita and Kumada provides the most accurate predictions for the thermal conductivity of bentonite. For the bentonite silica-sand mixtures, the correlation of Bruggeman predicts the thermal conductivity with sufficient accuracy. The correlation of Fricke is also a good correlation to predict the thermal conductivity of mixtures of bentonite and silica-sand, provided the real shape of sand particles is simulated as a spheroid.