Thermal Properties of Consolidated Granular Salt as a Backfill Material
Thermal Properties of Consolidated Granular Salt as a Backfill Material
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固结颗粒盐作为回填材料的热性能
DOI：
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发表时间：
2018
影响因子：
6.2
通讯作者：
J. Stormont
中科院分区：
文献类型：
--
作者：
L. P. Paneru;S. Bauer;J. Stormont
粒状盐已被提议作为核废料处置设施的巷道和竖井中的回填材料，在那里它将用于将热量从废料传导到主岩石。岩盐中开挖的蠕变闭合将加固（减少孔隙度）粒状盐。这项研究涉及测量的导热系数和比热的粒状盐作为孔隙度和温度的函数，以帮助了解如何在粒状盐固结过程中的热性能将发生变化，在压力和温度下完成一致的核废料处理设施。采用瞬态平面源法，在50 ~ 250 °C温度范围内，对实验室固结颗粒盐和现场固结颗粒盐样品的热性质进行了测量。对岩盐的单晶和膨胀的多晶岩盐进行了额外的测量。颗粒盐的导热系数随温度和孔隙度的增加而减小。在较低温度下，粒状盐的比热随孔隙度的增加而减小。在较高的温度下，孔隙度的依赖性是不明显的。的热导率和比热数据拟合经验模型，并与文献中提出的结果进行比较。在可比的密度，在这项研究中的流体静力学巩固的粒状盐样品的热导率大于那些先前测量的准静态压制形成的样品。固结盐的岩相学研究表明，固结方法影响的孔隙度的性质，这些意见被用来解释两种固结方法之间测得的热导率的变化。膨胀多晶盐的热导率低于固结盐在可比的孔隙率。与流体静力固结的盐相比，在膨胀盐中沿着沿着晶界的遍布的裂纹网络阻碍了热流动并导致较低的热导率。
Granular salt has been proposed as backfill material in drifts and shafts of a nuclear waste disposal facility where it will serve to conduct heat away from the waste to the host rock. Creep closure of excavations in rock salt will consolidate (reduce the porosity of) the granular salt. This study involved measuring the thermal conductivity and specific heat of granular salt as a function of porosity and temperature to aid in understanding how thermal properties will change during granular salt consolidation accomplished at pressures and temperatures consistent with a nuclear waste disposal facility. Thermal properties of samples from laboratory-consolidated granular salt and in situ consolidated granular salt were measured using a transient plane source method at temperatures ranging from 50 to 250 °C. Additional measurements were taken on a single crystal of halite and dilated polycrystalline rock salt. Thermal conductivity of granular salt decreased with increases in temperature and porosity. Specific heat of granular salt at lower temperatures decreased with increasing porosity. At higher temperatures, porosity dependence was not apparent. The thermal conductivity and specific heat data were fit to empirical models and compared with results presented in the literature. At comparable densities, the thermal conductivities of granular salt samples consolidated hydrostatically in this study were greater than those measured previously on samples formed by quasi-static pressing. Petrographic studies of the consolidated salt indicate that the consolidation method influenced the nature of the porosity; these observations are used to explain the variation of measured thermal conductivities between the two consolidation methods. Thermal conductivity of dilated polycrystalline salt was lower than consolidated salt at comparable porosities. The pervasive crack network along grain boundaries in dilated salt impedes heat flow and results in a lower thermal conductivity compared to hydrostatically consolidated salt.