膨润土-砂混合物缓冲层径向热传导性

膨润土-砂混合物作为高放废物处置库缓冲材料,在核废料衰变热影响作用下,其稳定性及物理力学性能产生显著变化,这对缓冲回填材料的包封阻隔作用及处置库的安全运行产生重要影响。本研究采用自行设计的装置对按比例缩小后的不同干密度、含水率、掺砂率试样进行热传导模拟试验,并对试验过程进行热-力耦合数值模拟分析,得到了缓冲层温度、应力和应变的变化及分布情况。结果表明,增大试样干密度、含水率和掺砂率均可提高导热性,应力和应变也随之增大,且不同含水率试样产生的结果变化显著；缓冲层靠近热源的位置温度、应力和应变最大,且沿径向方向减小,初始时刻各值变化显著。

Radial thermal conductivity test of bentonite-sand mixed buffer layer and numerical simulation

Bentonite-sand mixture as a buffer material for high radioactive waste disposal repository, under the influence of heat released from the decay of nuclear waste, its stability and physical and mechanical properties have significant changes, this has an important impact on the sealing blocking of the buffer backfill material and the safe operation of the disposal repository. In this study, a self-designed device was used to conduct a heat conduction simulation test for samples with different dry densities, water content and sand content after scaling reduction, and a thermo-force coupling numerical simulation analysis was conducted on the test process, the variation and distribution of temperature, stress and strain of the buffer layer are obtained. The results show that increasing the dry density, water content and sand content can improve the thermal conductivity and increase the stress and strain, the results of samples with different water content varied significantly; at the position of the buffer layer near the heat source, the temperature, stress and strain are the largest, and decrease along the radial direction, the values change significantly at the beginning.